Gold exploration in the Gabal Abu Karahish area, Central Eastern Desert, Egypt, using remote sensing and analytical techniques

Gold exploration in the Gabal Abu Karahish area, Central Eastern Desert, Egypt, using remote sensing and analytical techniques | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Gold exploration in the Gabal Abu Karahish area, Central Eastern Desert, Egypt, using remote sensing and analytical techniques Mahmoud Abd El-Rahman Hegab, Salem Mohamed Salem, Nehal Mohamed Soliman, and 5 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-5148766/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract This study focuses on exploring the presence and distribution of gold deposits in the Gabal Abu Karahish area, where volcanic and plutonic rocks and structural settings form valid geological environments for mineral exploration due to mineral-bearing hydrothermal activity in tectonized areas. Various tools have been integrated to determine gold potential and availability in this are In addition, for ASTER image processing band ratios 7/6_4/6 and 7/8, radiometric data, field geology, and spectral measurements of the specific rocks were combined to differentiate the alteration zones as promised localities for gold exploration. Several alteration zones of argellic, phyllic, and propylitic alteration types have been developed and localized. They are mainly associated with altered minerals such as chlorite, calcite, kaolinite, sericite, carbonates, and iron oxides. Scanning electron microscopy (SEM) images of ten representative samples from the alteration zones and quartz veins in the meavolcanics and ultramafics revealed that gold is present in all samples at average contents between 0.23 and 0.83 (from a bulk of 50 g of rock powder). These results indicate and suggest promising alteration zones for gold exploration. The study area consists of calc-alkaline metavolcanic rocks and younger Dokhan volcanic rocks. The metavolcanics are overthrusted by slices of serpentinites and talc carbonates, where some listwanite ridges (iron carbonate silica) developed along such contacts. Hornblende gabbros are present in small outcrops to the northeast of Gabal Abu Qarahish. Tonalite and granodiorite rocks are found in several localities, with most outcropsrecorded at Gabal Semna, where younger granite plutons intruded into the metavolcanics and surrounding rocks. The Dokhan volcanic sequence, composed mostly of quartz-feldspar porphyrite and andesite porphyry, is interlayered with siltstone, mudstone, and polymictic conglomerates typical of molasse-type Hammamat sediments. Geology Remote sensing ASTER Alteration zones Abu Karahish area Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 Figure 10 Figure 11 Figure 12 Figure 13 Figure 14 Figure 15 1. Introduction In the study area, hydrothermal fluids, driven by either metamorphism or the cooling of early Cambrian subduction-related calc-alkaline magmatism, have the potential to generate a range of mineral deposits (Pohl, 1988; Johnson et al., 2011; Hegab et al., 2022 ). Mineral-bearing hydrothermal solutions monitor rock lineaments and fractures as channel ways for fluid flow through country rocks, leaving marked alteration zones and altered minerals that may charge with valuable minerals. The study area comprises a geological environment of lineaments and fractured rocks suitable for hydrothermal activity, which may lead to gold precipitation in such an environment. Hence, this study suggests that the alteration zones should be pinpointed for exploring gold therein. The occurrence, distribution, and alteration of minerals are controlled mainly by rock tectonics and structures based on the original composition and intensity of hydrothermal fluids (Hegab et al., 2023 ). Chemical reactions and metasomatism with surrounding rocks led to the development and precipitation of altered and valued minerals along and around structural lineaments. In this way, ASTER remote sensing data are highly effective at distinguishing various altered minerals and are used for automated lineament mapping, which helps in identifying hydrothermal alteration zones. ASTER possesses six SWIR bands through which most minerals are easily distinguishable from each other. This technique has gained worldwide acceptance for alteration zone differentiation and mineral mapping by linking these alterations to their availability and suitability for mineral exploration. Many authors have used ASTER data to illustrate alteration zones from host rocks (Van Ruitenbeek, et al., 2006 ; Moore et al. 2008; Tangestani et al., 2011 ; Salem et al., 2013 ; Tripathi et al., 2020 ; Hegab, 2021 ; Mahmoud et al., 2023 ). This study aimed to discover gold in different geological environments in the Gabal Abu Karahish-Gabal Semna area, in alteration zones, in association with copper country rocks and in quartz veins. 2. Geologic setting The study area is situated in the Central Eastern Desert, south of the Safaga–Qena road and Abu Marawat mine, directly east of Wadi Saqia (Fig. 1). On the geologic map (Fig. 2) of EGSMA ( 1992 ), a sequence of banded iron formations (BIFs) occurs and is hosted in the metavolcanics in the northern Gabal Abu Karahish area, where the metavolcanics and metavolcanic rocks are over-rusted by serpentinite masses and talc carbonates. The Dokhan volcanics primarily consist of massive and laminated porphyritic rhyolite and rhyodacite, with andesite being less common. Few hornblende gabbros and small tonalite granodiorite rocks intrude the metavolcanics and ultramafics. Moreover, younger granites from Gabal Abu Qarahish, Gabal Wae’ra, and Gabal Kab Amiri intruded into the metavolcanics, which may be associated with mineral-bearing hydrothermal solutions and developing alteration zones. The study area is primarily composed of older metavolcanics. Zoheir and Akawy ( 2010 ) noted that the subaerial Dokhan volcanic rocks, which include quartz-feldspar porphyrite and andesite porphyry, are interlayered with siltstone, mudstone, and polymictic conglomerates typical of molasse-type Hammamat sediments. 3. Materials and methods The methodological framework of this study was constructed by integrating remote sensing (Landsat-8 (OLI) and ASTER) data taken from the ( https://earthexplorer.usgs.gov ) website. The results of the image processing were proven by fieldwork, where geological explanations and GPS validation points were gathered to check the lithology and alteration zones provided by remote sensing. Several rock and altered samples were composed of various rock units for scanning electron microscopy (SEM) and field spectral measurements. These tools were integrated and helped in lithological discrimination and mapping of alteration zones as target areas for gold exploration. The Landsat-8 and ASTER satellite data were preprocessed to retrieve surface reflectance values for each pixel and to correct errors caused by atmospheric interactions. Spatial resolution merging and area of interest steps were used. Then, numerous image processing approaches were applied to the Landsat-8 satellite data to identify the various lithological units to display the spatial distribution of the alteration zones. 4. Results 4.1. Lithological mapping using Landsat-8 data 4.1.1. False color composite (FCC) The optimal band triplets for false color composite images were selected using two methods: correlation coefficients (CCs) and the optimum index factor (OIF). The correlation coefficient method is a statistical approach used to assess the strength of the linear relationship between variables. A smaller correlation coefficient signifies a higher level of variance in the data. By using ENVI image processing software, the correlation coefficient between every two bands was obtained for the seven VNIR-SWIR reflective bands and the correlation matrix (Table 1 ). The correlation coefficient results revealed a positive correlation between all seven VNIR-SWIR bands. The correlation coefficients for the ten band triplets are presented and ranked in Table 2 . Table 1 Correlation coefficients of Landsat 8 images Bands Band1 Band2 Band3 Band4 Band5 Band6 Band7 Band1 1 Band2 0.998121 1 Band3 0.989656 0.992927 1 Band4 0.968145 0.973071 0.989795 1 Band5 0.939839 0.945918 0.96826 0.992534 1 Band6 0.906028 0.911217 0.936791 0.956796 0.964928 1 Band7 0.896672 0.900558 0.923468 0.937092 0.940756 0.980317 1 Table 2 Ranking of the top ten band triplets for Landsat 8 data in the study area was performed using the correlation coefficient method. Band Triplet Correlation coefficients Rank 157 2.777267 1 167 2.783017 2 257 2.787232 3 267 2.792092 4 127 2.795351 5 147 2.801909 6 137 2.809796 7 247 2.810721 8 156 2.810795 9 126 2.815366 10 The optimum index factor method was developed by Chavez et al. ( 1982 & 1984 ). The OIF is a statistical calculation used to evaluate all possible three-band combinations, such as RGB. The OIF values are computed to identify the most favorable band combinations, as described by Cengiz et al. ( 2006 ), and the band triplets are ranked based on the information contained in each combination (Beaudemin and Fung, 2001 ). The potential for RGB visualization is determined by the total variance and correlation between different bands (Jensen, 1996). Triplets with higher OIF values were selected for better lithological discrimination, as they include bands with maximum variance and minimal redundancy (Qaid and Basavarajappa, 2008). The top ten band triplet combinations are listed in Table 3 . Table 3 Ranking of Landsat 8 Data Obtained Using OIF for the Study Area Band Triplet OIF Rank 567 0.068248 1 467 0.065993 2 456 0.063795 3 367 0.062326 4 457 0.062199 5 356 0.060376 6 267 0.058863 7 357 0.05857 8 167 0.057951 9 567 0.068248 10 Through visual inspection of the selected best band triplet possibilities obtained from both the CC and OIF methods, RGB images 7, 5, 1, 7, 6, 2, 7, 2, 1 and 7, 4, 1 in RGB were selected for better lithological discrimination of the exposed rocks in the area (Fig. 3, a,b,c,d) 4.1.2. Principal component analysis (PCA) The advantage of PCA (Mohy, 2013 ; Hegab and Salem, 2021 ) is that in multispectral data, the majority of the variance is usually concentrated in the first three or four principal component images. Noise tends to accumulate in the less correlated principal components. The first principal component (PC) image captures the most variance and has the lowest correlation, while the last PC image contains the least variance and highest correlation, making the lower-order principal components less useful (e.g., the last principal component image) appear noisy and one cannot identify the features in it clearly. Table 4 Eigenvector matrix and loading of principal component analysis on Landsat 8 images PC 1 PC 2 PC 3 PC 4 PC 5 PC 6 PC 7 Band 1 -0.94170 -0.32103 0.09485 -0.01849 -0.02782 -0.00108 -0.00476 Band 2 0.24145 -0.84451 -0.45793 -0.10892 0.08302 0.00647 0.00090 Band 3 0.20250 -0.34696 0.84898 -0.26582 0.21518 0.00409 0.02947 Band 4 -0.05334 0.17872 -0.16485 -0.95084 -0.18250 -0.01088 -0.02274 Band 5 -0.10342 0.17392 -0.17947 -0.11301 0.91483 0.18942 0.20321 Band 6 0.01662 -0.03269 0.02497 0.01515 -0.27058 0.49285 0.82564 Band 7 -0.00873 0.00984 -0.02296 -0.00632 0.05106 -0.84914 0.52499 Eigenvalues 0.01824 0.00046 0.00015 0.00006 0.00001 0.00000 0.00000 0.96401 0.02442 0.00766 0.00328 0.00048 0.00011 0.00005 % 96.40 2.44 0.77 0.33 0.05 0.01 0.01 The principal components were computed from the VNIR and SWIR data bands in the present study. According to the analysis of the eigenvector matrix (Table 4), PC1, 2, 3, and 4 contained almost 99.9% of the information in the data, while the other PC bands contained less than 0.1%. Hence PC3, PC2, and PC1; PC4 and PC2 and PC1 were used, so they contained the most informative data with the highest variance. These data clearly show the relationships between the different rock units and illustrate the general structural features flanking these rocks (Figure 4a, b, c). 4.1.3. Color Ratio Composites (CRC) This method effectively distinguishes between rock types by highlighting the primary differences in the visible, near-infrared, and shortwave-infrared spectral regions, which are evident along the slopes of the reflectivity curves. The rationing process mitigates first-order brightness effects induced by topographic slopes and accentuates subtle color variations between materials (Abrams et al., 1983 ). Ratio images are generated by dividing the digital number, radiance, or reflectance values of one band by those of another band for each pixel. The resulting ratios are subsequently normalized and visualized as a new ratio image (Sabins, 1997). In the present study, the composite ratios (6/7, 5/6 and 4/2) in RGB were verified to be the optimum mixtures for lithological discrimination and differentiation of the alteration zones from their host rocks (Fig. 5). Moreover, various ratios (6/7, 5/2 and 4/5*6/5) were also used for alteration mapping, which mainly revealed yellow to yellowish green colors (Fig. 6). 4.2. Automatic Lineament Extraction Extracting lineaments from satellite remotely sensed data for mapping line weakness zones of lineaments faults, joints, cracks, fissures or other linear features is becoming a common automatic process. The importance of mapping linear features is that they represent channels and paths for mineral-bearing hydrothermal solutions. Hydrothermal chemical activity within the surrounding country rocks led to the development of haloes in alteration zones within and around the lineament zones. The types and extensions of these alterations depend on the composition and intensity of such solutions. According to Gupta ( 2003 ), the lineaments represent areas of deformation and higher secondary porosity and are significant channels for fluid migration. Hung et al. ( 2005 ) described lineaments as linear features. Madani and Bishta ( 2002 ) selected the optimal Landsat ETM + bands for automatic lineament extraction and evaluated the relationship between the extracted lineament trends and the presence of uranium in granitic rocks. Mostafa and Bishta ( 2004 ) extracted lineaments from the digital Landsat ETM + for the Gabal Gharib-Dara area using Geo-analyst PCI software. Abo Qudaira ( 2007 ) used SPOT imagery Geomatica PCI Package to extract lineaments Petra-Wadi Al Lahyana area, Jordan. Ghoneim et al. ( 2022 ) derived lineaments from multiple hill shade images with multiple illumination azimuths (0, 45, 90, 135, 180, 225, 270, and 315) that were generated from PAlSAR DEM data via ArcMap v.10.5 software. In the present research lineament and lineament density maps were extracted from shaded relief images (Figs. 7 and 8) and subsequently correlated and integrated with the obtained alteration information to map the areas with the most potential for mineral exploration. Lineaments are analyzed using density maps (Zakir et al., 1999 ). There are two main methods for calculating lineament density: counting the number of lineaments per unit area (number/km²) or summing the lengths of lineaments per unit area (km/km²). In this study, we used ArcGIS v.10.5 software to calculate lineament density based on the number of lineaments per unit area (number/km²). The lineament density map (Fig. 8) illustrates the frequency and concentration of lineaments across the study area. Lineaments are analyzed using density maps (Zakir et al., 1999 ). There are two main methods for calculating lineament density: counting the number of lineaments per unit area (number/km²) or summing the lengths of lineaments per unit area (km/km²). In this study, we used ArcGIS v.10.5 software to calculate lineament density based on the number of lineaments per unit area (number/km²). The lineament density map (Fig. 8) illustrates the frequency and concentration of lineaments across the study area. 4.3. Alteration mapping using ASTER data 4.3.1. Spectral ratio indices (SRIs) Several mineralogical spectral ratio indices have been proposed by Hewson et al. ( 2001 ) and Ninomiya ( 2003 ) to map alteration zones and associated altered minerals, where altered minerals are present. In this study, the OHI, KLI, and CLI indices, in addition to the iron oxide indices of b2/b1, were applied for alteration mapping. The interpretations of such applications reveal that the distributions of OH-bearing, kaolinite, and iron oxide minerals are associated mainly with acidic rocks (Fig. 9). Where OHI is the index of the OH-bearing minerals, KLI is the index of kaolinite minerals, and CLI is the index of calcite minerals. 4.3.2. Constrained Energy Minimization (CEM) The CEM method focuses on the spectral response of specific features while suppressing the responses of other features, treating them as unknown backgrounds. In this study, the CEM method of ASTER VNIR-SWIR surface reflectance data enabled the identification and mapping of the distributions of the most dominant altered minerals montmorillonite, sericite, illite, alunite, and kaolinite (Fig. 10). The altered clay minerals were found to be associated with acidic metavolcanics and Dokhan volcanics. Iron oxides and carbonates are mainly present in the western part, where the intermediate metavolcanics and ultramafic rocks are exposed. Sericite and kaolinite are recorded in a belt trending NE‒SW directly to the north of Gabal Abu Qarahish. In the metavolcanics and the older granites northward of Gabal Semna, there are altered minerals, including kaolinite, montmorillonite, and sericite, associated with the alteration zones. 4.3.3. Crosta principal component analysis (CPCA) The studies of Crosta and Moore (1989) have harnessed the power of PCA to unravel the intricate spectral signatures of alteration minerals. Drawing from the extensive resources of the US Geological Survey (USGS) spectral library, these endeavors meticulously identified optimal bands that encapsulate the maximum reflectance and absorption features specific to each alteration mineral. For instance, the spectral behavior of kaolinite is discerned by its pronounced reflectance patterns in bands 4 and 7, juxtaposed with lower reflectance in bands 6 and 9 within the VNIR-SWIR spectral range (Table 5 ). Such meticulous observations, facilitated by the PCA process using four input bands, culminate in its vivid representation. Similarly, illite, alunite, montmorillonite, and hematite exhibit unique spectral characteristics, all of which are meticulously discerned through the intricate PCA technique. Table 5: Eigenvector statistics of selected ASTER bands 4, 6, 7 and 9 for kaolinite Eigenvector B4↑ B6↓ B7↑ B9↓ Stdev Eigenvalue Eigen% PC 1 0.9624 -0.18021 0.189971 -0.07225 0.080356 0.006967 97.8 PC 2 -0.18756 -0.14708 0.924177 0.298472 0.016923 0.000079 1.1 PC 3 -0.10212 -0.92265 -0.25499 0.270689 0.017982 0.000067 0.9 PC 4 -0.16787 -0.30758 0.211639 -0.91237 0.007529 0.00001 0.2 Table 6: Eigenvector statistics of selected ASTER bands 4, 6, 7 and 8 for illite Eigenvector B4↑ B6↓ B7↑ B8↓ Stdev Eigenvalue Eigen% PC 1 0.982195 0.090829 -0.15934 -0.04065 0.084914 0.007471 97.6 PC 2 0.11263 -0.96656 0.179984 -0.14381 0.012498 0.000098 1.3 PC 3 0.13479 0.206267 0.966556 -0.07109 0.016143 0.000072 0.9 PC 4 -0.06663 0.122327 -0.08935 -0.98621 0.005215 0.000013 0.2 Table 7: Eigenvector statistics of selected ASTER bands 3, 5, 7 and 9 for alunite Eigenvector B3↑ B5↓ B7↑ B9↓ Stdev Eigenvalue Eigen% PC 1 0.972396 0.126403 -0.10135 0.167918 0.076147 0.006129 94.7 PC 2 0.098645 -0.98439 -0.06548 0.130245 0.019146 0.000277 4.3 PC 3 0.051042 -0.01934 0.953996 0.294808 0.010675 0.000054 0.8 PC 4 0.205209 -0.12096 0.274464 -0.93163 0.013904 0.000013 0.2 Table 8: Eigenvector statistics of selected ASTER bands 3, 6, 7 and 9 for montmorillonite Eigenvector B3↑ B6↓ B7↑ B9↓ Stdev Eigenvalue Eigen% PC 1 0.972406 0.141543 -0.06403 0.174045 0.075245 0.005983 94.6 PC 2 0.114281 -0.98187 -0.03487 0.147178 0.019331 0.000263 4.2 PC 3 0.028821 -0.00139 0.979289 0.200399 0.009408 0.000066 1 PC 4 -0.20133 0.1261 -0.18888 0.952831 0.014152 0.000012 0.2 Table 9: Eigenvector statistics of selected ASTER bands 2, 3, 4 and 9 for iron oxides Eigenvector B2↑ B3↓ B4↑ B9↓ Stdev Eigenvalue Eigen% PC 1 0.963953 0.090142 -0.24649 0.043718 0.083281 0.007461 95.2 PC 2 0.013996 0.918021 0.395329 0.027491 0.018285 0.000318 4.1 PC 3 -0.25766 0.38613 -0.88159 -0.08547 0.023085 0.000038 0.5 PC 4 -0.06487 0.003844 -0.07582 0.995001 0.005696 0.000018 0.2 Kaolinite exhibits significant reflectance characteristics in bands 4 and 7, with notably lower reflectances in bands 6 and 9 within the VNIR-SWIR spectral region. These spectral bands were subjected to principal component analysis (PCA), which yielded four principal components (PCs), as detailed in Table 5 . PC2 demonstrated the highest positive loadings from band 7 (0.924177) and band 9 (0.298472), resulting in the representation of kaolinite as blue in the resultant image. Similarly, illite displays pronounced reflectance in bands 4 and 7, alongside reduced reflectance in bands 6 and 8. The PCA conducted with these bands, as summarized in Table 6 , revealed that PC3 exhibited the highest loadings from band 7 (0.966556) and band 6 (0.206267), depicting illite as yellow in the resultant imagery. Alunite is characterized by high reflectance in bands 3 and 7 coupled with low reflectance in bands 5 and 9. The PCA results presented in Table indicate that PC3 displayed significant positive loadings from band 7 (0.953996) and band 9 (0.294808), indicating that the alunite was a large sky (red). Montmorillonite similarly shows high reflectance in bands 3 and 7, with low reflectance in bands 6 and 9. PCA outlined in Table 8 , revealed that PC3 exhibited high positive loadings from band 7 (0.979289) and band 9 (0.200399), resulting in the representation of montmorillonite as green. Hematite has high reflectance in bands 2 and 4 and low reflectance in bands 3 and 9. The PCA of these bands, detailed in Table 9 , indicated that PC2 had high positive loadings from band 3 (0.918021) and band 4 (0.395329), resulting in hematite being depicted as brown in the final image. The application of the CPCA method to ASTER data for mapping altered minerals revealed significant spatial coincidence among these minerals. This analysis effectively delineated alteration zones (Fig. 11) that could be used for gold exploration at Gabal Semna and Gabal Abu Karahish, providing critical insights for targeted geological assessments. 4.4. Spatial relation between the lineaments and alterations The obtained lineament density map was correlated with the provided altered mineral abundance map, which revealed an intimate spatial relation where dense lineaments are confined by the location and distribution of alteration zones. The results of such integration revealed several alteration zones regarded as potentially high-elevation areas for mineral exploration. The known Semna and Abu Qarahish mine areas are delineated areas (Fig. 12). 4.5. Field verification Some field visits have been assumed to verify the results from remote sensing and to locate structurally controlled alteration zones and associated altered minerals. Moreover selective samples were collected from the quartz veins and alteration zones of various rocks for SEM analysis and gold detection (Fig. 13). In the Gabal Abu Karahish area, the metavolcanics are partly overthrusted by serpentinite and talc carbonate masses, where several alterations in iron carbonate and silica (listwanite ridges) developed along contacts with the metavolcanics, forming a valid geological environment for gold exploration. The metavolcanics intrude younger granite plutons and several felsite sheets and plugs in the Gabal Abu Qarahish, Gabal Wae’ra and Gabal Kab Amiri areas (Fig. 14). Moreover, the gabbroic and older granitic plutons intrude the acidic metavolcanics and ultramafics in the northern Gabal Semna area. Near the intrusions in the metavolcanics, there are several quartz veins, veinlets, plugs and offshoots of milky and smoky type crosscutting the country rocks of different sizes with varied trends; they are enriched in sulfides and iron oxides, which may enclose gold. Ten samples from the altered zones, quartz veins, and country rocks were exposed via electron microscopy (SEM) to detect and assess the gold content and related elements in the study area. All the rock samples contained less than 1% Au in a total bulk of 50 grams for each crushed sample. The analyzed samples have gold contents ranging from 0.08–0.83% and silver contents ranging from 0.01–0.10% (Fig. 15). Sample 2 from the altered metavolcanics contains the highest gold value of 0.83% Au ppm, while Sample 5 from the altered metavolcanics also has a lower Au content of 0.08 Au ppm. The gold is mainly hosted in pyrie and arsenpyrite crystals and is associated with the following elements at different percentages and randomly related to gold. However, a reverse relationship between gold and Si% is shown in most samples due to the alteration and increase in clay minerals at the expense of silica. The copper (Cu) content ranged from 0.02–2.07%, the aluminum (Al) content ranged from 0.44–11.19%, the oxygen (O) content ranged from 30.74–53.79%, the carbon (C) content ranged from 10.97–41.42%, the calcium (Ca) content ranged from 1.07–6.19%, the silicon (Si) content ranged from 6.19–40.02%, the iron (Fe) content ranged from 1.10–35.21%, and the hafnium (Hf) content ranged from 0.03–0.28%. In the alteration zones, a relatively greater percentage of gold is found in the alteration zones than in the country rocks, and more or less than in the quartz veins. In the studied altered zones, silver and copper are frequently connected to gold. Ilmenite, rutile, cobaltite, and barite are occasionally found along with sulfides and iron oxides (the host minerals of gold). The contents of Au, Ag, and their related elements are comparatively high in the altered and quartz vein samples. 5. Discussion Exploring new gold fields in the alteration zones of the areas surrounding the Gabal Abu Karahish and Semna mines is the goal of this study. For this purpose, enhanced mapping of lithological units was necessary for mapping alteration zones as target areas for gold exploration. In this way, several remote sensing techniques were useful for obtaining Landsat-8 satellite and ASTER data for accurate geological and alteration mapping. Moreover, geological field verification and SEM analysis were performed to support the existence and localization of the alteration zones and their gold potentiality in the study area. The granitic and gabbroic intrusions in the country rocks are mainly associated with mineral-bearing hydrothermal fluids and residual silica that percolate and ascend through rock lineaments and fractures. The chemical activity and metasomatism of the solutions to the surrounding rocks leave marks of alteration hallows with altered and valued mineral precipitation along the hydrothermal flowing zones. Moreover, sulfide-bearing quartz veins and associated hydrothermal breccia bodies exhibit a variety of textures, including sheared, badinage, and recrystallized quartz, as well as open-space filling and micro breccia within the alteration zones. These textures indicate a complex crack-seal mechanism that highlights the interaction between mineral deposition and a significant N–S-trending shear zone. This relationship is a result of a late brittle–ductile deformation event that impacted the area approximately 550 million years ago. These alteration zones, characterized by variable textures, are promising targets for gold exploration. The automatic extraction of the lineaments was also implemented in the localization of the alteration zones, where the rock lineaments represent zones of deformation that imply secondary porosity as channels for the migration of hydrothermal solutions that help in forming and developing alteration zones along their paths. Moreover, the alteration and lineament data were integrated to delineate the most potential localities for gold exploration, where the special distribution and density of the extracted lineaments are mainly coincident and correlated with the presence of alteration zones and altered minerals in the study area. Zoheir et al. (2008) reported that at a temperature of approximately 250°C and pressure of 2.3 kbars, shear zones, and associated alteration zones, combined with the upward migration of hydrothermal fluids, led to a pressure drop. This pressure drop caused the separation of an aqueous phase and a carbonic phase. The resulting alteration assemblage includes quartz, chlorite, pyrite, calcite, and possibly epidote, with pervasive silicification, pyritization, sericitization, and carbonatization processes contributing to hydrothermal alteration. Additionally, sets of quartz veins and altered shears are significant indicators of hydrothermal alteration. Azizi (2010) and Salem et al. ( 2016 ) used SWIR ASTER data to identify alteration zones in the Barramiya district of Egypt and the eastern Zanjan district in northern Iran, respectively. In the El Sid gold mine area, following the emplacement of granite, hydrothermal fluids interacted with sheared serpentinite. These interactions led to metal leaching and re-deposition in adjacent wall rocks and faults through cyclic processes (Helmi and Zoheir, 2014; Ghoneim, 2019, 2020). Alteration zones in the study area were mapped using various remote sensing approaches, including spectral ratio indices (SRIs), constrained energy minimization (CEM), and Crosta principal component analysis (CPCA). The results from fieldwork and SEM analysis corroborated these remote sensing findings. Specifically, the alteration zones identified using ASTER data were verified through field observations, confirming their locations and association with gold mineralization. Conclusion The VNIR and SWIR bands of ASTER provide highly accurate data for detecting even limited and restricted alteration zones, making ASTER data extremely effective for mapping alteration zones and altered minerals. Band math formulas such as (b7 + b9)/b8 (b7 + b9)/b8 (b7 + b9)/b8 are useful for identifying carbonate, chlorite, and epidote minerals, while (b5 + b7)/b6 (b5 + b7) b6(b5 + b7)/b6 help illustrate confined sericite and clay minerals, which are indicative of gold occurrences. A band ratio of 4/54/54/5 is particularly effective for detailed mapping of alteration zones. Remote sensing techniques such as the SAM, SFF, CEM, and MTMF are the most effective for mapping the spatial distribution of endmembers using ASTER satellite data. This study identifies gold occurrences in two main altered geological environments: 1) altered listennites, 2) altered pyritized metavolcanics, and 3) crosscutting quartz veins in the country rocks. These alterations, including sericitization, chloritization, silicification, and carbonization, are linked to fracture fillings and are readily identifiable on the surface. Large areas of intense alteration in the ultramafic and metavolcanic rocks of the Gabal Abu Karahish and Gabal Semna areas suggest potential sites for gold mineralization. SEM analysis, which showed that all the analyzed samples contained approximately 1% gold by bulk (approximately 50 grams per sample), supported this potential. The methodologies used, particularly the SRI and CEM, demonstrated a high degree of confidence and are recommended for alteration mapping in similar areas. Further detailed exploration is advised to maximize the use of the identified mineral resources, as the delineated potentially mineralized sites have been validated in the field and present promising targets for gold exploration. Declarations Conflict of interest: The authors have no financial or personal interests that could have influenced the results or interpretation of this research. Funding: We did not receive any funding for this study. Authors Contributions: Each author played a key role in the study, from designing and conducting the research to analyzing the data and writing the manuscript. Data availability: If you are interested in the data from this study, please contact the corresponding author. The data will be shared upon reasonable request. 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area.\u003c/p\u003e","description":"","filename":"1.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-5148766/v1/d463ddb0d66462ec5f9a7090.jpeg"},{"id":65703731,"identity":"df3a226d-85d7-4e0d-9023-cd5cb4d7ee6e","added_by":"auto","created_at":"2024-10-01 12:43:30","extension":"jpeg","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":553834,"visible":true,"origin":"","legend":"\u003cp\u003eGeologic map of the study area (EGSMA, 1992).\u003c/p\u003e","description":"","filename":"2.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-5148766/v1/6f9db0766e5cc8cf644ae6f1.jpeg"},{"id":65705501,"identity":"f1b99120-4eaf-43b7-ad6b-51485d4a0406","added_by":"auto","created_at":"2024-10-01 12:59:31","extension":"jpeg","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":7824632,"visible":true,"origin":"","legend":"\u003cp\u003eLandsat 8 FCC images (a) 7, 5, 1 (b) 7, 6, 1 (c) 7, 6, 5, and (d) 6, 5, 4 in RGB, respectively.\u003c/p\u003e","description":"","filename":"3.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-5148766/v1/100435188e3952943ae295d0.jpeg"},{"id":65706100,"identity":"0803c21f-090d-4a01-83d4-3a77383da2b4","added_by":"auto","created_at":"2024-10-01 13:15:31","extension":"jpeg","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":16875054,"visible":true,"origin":"","legend":"\u003cp\u003eLandsat 8 false color composite (a) PC3, PC2, PC1 (b) PC4, PC2, PC1 and (c) PC4, PC3, PC1 in (RGB) respectively.\u003c/p\u003e","description":"","filename":"4.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-5148766/v1/30e57b81b8531c069d2cac33.jpeg"},{"id":65704083,"identity":"1e05781a-5398-4037-9598-71ade85c7e49","added_by":"auto","created_at":"2024-10-01 12:51:31","extension":"jpeg","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":247277,"visible":true,"origin":"","legend":"\u003cp\u003eLandsat-8 band ratio (6/7, 5/6, 4/2) RGB (modified after Abrams et al, 1983).\u003c/p\u003e","description":"","filename":"5.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-5148766/v1/ca0a4292155d34b8088b82e4.jpeg"},{"id":65704079,"identity":"9be92300-c4e9-49d2-8442-df27fc981af5","added_by":"auto","created_at":"2024-10-01 12:51:30","extension":"jpeg","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":228038,"visible":true,"origin":"","legend":"\u003cp\u003eLandsat-8 band ratio (6/7, 5/2, 4/5* 6/5) (modified after Sultan et al, 1986).\u003c/p\u003e","description":"","filename":"6.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-5148766/v1/5cfabe35f2e9051b696399f3.jpeg"},{"id":65703733,"identity":"429f6219-0ad9-4e16-a426-aa939ff0516d","added_by":"auto","created_at":"2024-10-01 12:43:30","extension":"jpeg","order_by":7,"title":"Figure 7","display":"","copyAsset":false,"role":"figure","size":133596,"visible":true,"origin":"","legend":"\u003cp\u003eAutomatically extracted lineaments map of the study area.\u003c/p\u003e","description":"","filename":"7.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-5148766/v1/907567076e33b110498a7659.jpeg"},{"id":65705498,"identity":"acc6f04b-9111-476b-a038-07963f898061","added_by":"auto","created_at":"2024-10-01 12:59:30","extension":"jpeg","order_by":8,"title":"Figure 8","display":"","copyAsset":false,"role":"figure","size":661825,"visible":true,"origin":"","legend":"\u003cp\u003eLineaments density map of the study area.\u003c/p\u003e","description":"","filename":"8.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-5148766/v1/2f951e05964702e35912426d.jpeg"},{"id":65703734,"identity":"15957123-00bd-4cb1-a27a-007732e7d44b","added_by":"auto","created_at":"2024-10-01 12:43:30","extension":"jpg","order_by":9,"title":"Figure 9","display":"","copyAsset":false,"role":"figure","size":294285,"visible":true,"origin":"","legend":"\u003cp\u003eAltered minerals distribution over the study area using the spectral ratio indices\u003c/p\u003e","description":"","filename":"9.jpg","url":"https://assets-eu.researchsquare.com/files/rs-5148766/v1/9cb9c008b1c994863369b2cf.jpg"},{"id":65705499,"identity":"64852fff-8217-4d1f-8ba6-aef341f3985f","added_by":"auto","created_at":"2024-10-01 12:59:31","extension":"jpg","order_by":10,"title":"Figure 10","display":"","copyAsset":false,"role":"figure","size":395310,"visible":true,"origin":"","legend":"\u003cp\u003eAltered minerals distribution over the study area using the CEM overlying ASTER band 3.\u003c/p\u003e","description":"","filename":"10.jpg","url":"https://assets-eu.researchsquare.com/files/rs-5148766/v1/a88ce8072f33e13bbce8c590.jpg"},{"id":65703738,"identity":"96d94243-03b2-4531-891e-03b52c526b89","added_by":"auto","created_at":"2024-10-01 12:43:30","extension":"jpg","order_by":11,"title":"Figure 11","display":"","copyAsset":false,"role":"figure","size":384716,"visible":true,"origin":"","legend":"\u003cp\u003eAltered minerals distribution over the study area using the CPCA overlying ASTER band 3.\u003c/p\u003e","description":"","filename":"11.jpg","url":"https://assets-eu.researchsquare.com/files/rs-5148766/v1/17b825b53341544280560338.jpg"},{"id":65704080,"identity":"539300c2-6ddc-48f1-9d7b-6722920b435b","added_by":"auto","created_at":"2024-10-01 12:51:30","extension":"jpg","order_by":12,"title":"Figure 12","display":"","copyAsset":false,"role":"figure","size":384716,"visible":true,"origin":"","legend":"\u003cp\u003eFinal integrated alteration-lineaments map illustrates several alteration zones and altered minerals; High lineaments contours are marked by red lines, moderate densities are in yellow and low lineaments densities are in green color.\u003c/p\u003e","description":"","filename":"12.jpg","url":"https://assets-eu.researchsquare.com/files/rs-5148766/v1/7fa9778f6d0ca14819789a39.jpg"},{"id":65703740,"identity":"c5c3c433-9aac-4bd2-b9a3-96df9652149d","added_by":"auto","created_at":"2024-10-01 12:43:31","extension":"jpg","order_by":13,"title":"Figure 13","display":"","copyAsset":false,"role":"figure","size":384716,"visible":true,"origin":"","legend":"\u003cp\u003eField station from which samples were collected and observations were recorded.\u003c/p\u003e","description":"","filename":"13.jpg","url":"https://assets-eu.researchsquare.com/files/rs-5148766/v1/f5f4cdd8e6b6af6a64dce6e6.jpg"},{"id":65705666,"identity":"229670fd-d617-4b9f-b0ee-066835fe9c2b","added_by":"auto","created_at":"2024-10-01 13:07:31","extension":"jpeg","order_by":14,"title":"Figure 14","display":"","copyAsset":false,"role":"figure","size":684617,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003e(A)\u003c/strong\u003e Milky and smoky Quartz plug enriched in sulphide and iron oxides near the granitic intrusion of the metavolcanics in the north Gabal Semna area, looking east. \u003cstrong\u003e(B)\u003c/strong\u003e metavolcanics intruded by metagabbro, in the north Gabal Semna area. \u003cstrong\u003e(C)\u003c/strong\u003e Alteration zones of metavolcanics in the north Gabal Semna area. \u003cstrong\u003e(D)\u003c/strong\u003e Younger granites intruding the metavolcanics, in the north Gabal Semna area. \u003cstrong\u003e(E)\u003c/strong\u003e \u003cstrong\u003e\u0026amp; (F)\u003c/strong\u003e Alteration zones of iron carbonate silica (listwaenite ridges), G. Semna area. \u003cstrong\u003e(G)\u003c/strong\u003e Thrust sheets of serpentinite and talc carbonates over the metavolcanics at G. Abu Karahish area. \u003cstrong\u003e(H)\u003c/strong\u003e \u003cstrong\u003e\u0026amp; (I)\u003c/strong\u003eAlteration zones of (listwaenite ridges), at G. Abu Karahish area.\u003c/p\u003e","description":"","filename":"14.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-5148766/v1/6d43259ab47b86a25b0dc236.jpeg"},{"id":65703746,"identity":"9e27c811-6d48-4821-b96b-1aaab65a7677","added_by":"auto","created_at":"2024-10-01 12:43:31","extension":"png","order_by":15,"title":"Figure 15","display":"","copyAsset":false,"role":"figure","size":3544824,"visible":true,"origin":"","legend":"\u003cp\u003eSEM image, sum spectrum and SEM analyses data of collected rock samples.\u003c/p\u003e","description":"","filename":"15.png","url":"https://assets-eu.researchsquare.com/files/rs-5148766/v1/c2180d7e9125d22a1bea28c0.png"},{"id":66638401,"identity":"36ef7621-8c42-45a3-91e3-1192903f3a2e","added_by":"auto","created_at":"2024-10-15 05:56:15","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":33263143,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-5148766/v1/2a9d45b4-4cc3-4472-98ad-fae0a3a9ebca.pdf"}],"financialInterests":"The authors declare no competing interests.","formattedTitle":"\u003cp\u003e\u003cstrong\u003eGold exploration in the Gabal Abu Karahish area, Central Eastern Desert, Egypt, using remote sensing and analytical techniques\u003c/strong\u003e\u003c/p\u003e","fulltext":[{"header":"1. Introduction","content":"\u003cp\u003eIn the study area, hydrothermal fluids, driven by either metamorphism or the cooling of early Cambrian subduction-related calc-alkaline magmatism, have the potential to generate a range of mineral deposits (Pohl, 1988; Johnson et al., 2011; Hegab et al., \u003cspan citationid=\"CR56\" class=\"CitationRef\"\u003e2022\u003c/span\u003e). Mineral-bearing hydrothermal solutions monitor rock lineaments and fractures as channel ways for fluid flow through country rocks, leaving marked alteration zones and altered minerals that may charge with valuable minerals. The study area comprises a geological environment of lineaments and fractured rocks suitable for hydrothermal activity, which may lead to gold precipitation in such an environment. Hence, this study suggests that the alteration zones should be pinpointed for exploring gold therein. The occurrence, distribution, and alteration of minerals are controlled mainly by rock tectonics and structures based on the original composition and intensity of hydrothermal fluids (Hegab et al., \u003cspan citationid=\"CR58\" class=\"CitationRef\"\u003e2023\u003c/span\u003e). Chemical reactions and metasomatism with surrounding rocks led to the development and precipitation of altered and valued minerals along and around structural lineaments. In this way, ASTER remote sensing data are highly effective at distinguishing various altered minerals and are used for automated lineament mapping, which helps in identifying hydrothermal alteration zones. ASTER possesses six SWIR bands through which most minerals are easily distinguishable from each other. This technique has gained worldwide acceptance for alteration zone differentiation and mineral mapping by linking these alterations to their availability and suitability for mineral exploration. Many authors have used ASTER data to illustrate alteration zones from host rocks (Van Ruitenbeek, et al., \u003cspan citationid=\"CR101\" class=\"CitationRef\"\u003e2006\u003c/span\u003e; Moore et al. 2008; Tangestani et al., \u003cspan citationid=\"CR97\" class=\"CitationRef\"\u003e2011\u003c/span\u003e; Salem et al., \u003cspan citationid=\"CR85\" class=\"CitationRef\"\u003e2013\u003c/span\u003e; Tripathi et al., \u003cspan citationid=\"CR98\" class=\"CitationRef\"\u003e2020\u003c/span\u003e; Hegab, \u003cspan citationid=\"CR57\" class=\"CitationRef\"\u003e2021\u003c/span\u003e; Mahmoud et al., \u003cspan citationid=\"CR73\" class=\"CitationRef\"\u003e2023\u003c/span\u003e). This study aimed to discover gold in different geological environments in the Gabal Abu Karahish-Gabal Semna area, in alteration zones, in association with copper country rocks and in quartz veins.\u003c/p\u003e"},{"header":"2. Geologic setting","content":"\u003cp\u003eThe study area is situated in the Central Eastern Desert, south of the Safaga\u0026ndash;Qena road and Abu Marawat mine, directly east of Wadi Saqia (Fig.\u0026nbsp;1). On the geologic map (Fig.\u0026nbsp;2) of EGSMA (\u003cspan class=\"CitationRef\"\u003e1992\u003c/span\u003e), a sequence of banded iron formations (BIFs) occurs and is hosted in the metavolcanics in the northern Gabal Abu Karahish area, where the metavolcanics and metavolcanic rocks are over-rusted by serpentinite masses and talc carbonates. The Dokhan volcanics primarily consist of massive and laminated porphyritic rhyolite and rhyodacite, with andesite being less common. Few hornblende gabbros and small tonalite granodiorite rocks intrude the metavolcanics and ultramafics. Moreover, younger granites from Gabal Abu Qarahish, Gabal Wae\u0026rsquo;ra, and Gabal Kab Amiri intruded into the metavolcanics, which may be associated with mineral-bearing hydrothermal solutions and developing alteration zones. The study area is primarily composed of older metavolcanics. Zoheir and Akawy (\u003cspan class=\"CitationRef\"\u003e2010\u003c/span\u003e) noted that the subaerial Dokhan volcanic rocks, which include quartz-feldspar porphyrite and andesite porphyry, are interlayered with siltstone, mudstone, and polymictic conglomerates typical of molasse-type Hammamat sediments.\u003c/p\u003e"},{"header":"3. Materials and methods","content":"\u003cp\u003eThe methodological framework of this study was constructed by integrating remote sensing (Landsat-8 (OLI) and ASTER) data taken from the (\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://earthexplorer.usgs.gov\u003c/span\u003e\u003cspan address=\"https://earthexplorer.usgs.gov\" targettype=\"URL\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e) website. The results of the image processing were proven by fieldwork, where geological explanations and GPS validation points were gathered to check the lithology and alteration zones provided by remote sensing. Several rock and altered samples were composed of various rock units for scanning electron microscopy (SEM) and field spectral measurements. These tools were integrated and helped in lithological discrimination and mapping of alteration zones as target areas for gold exploration. The Landsat-8 and ASTER satellite data were preprocessed to retrieve surface reflectance values for each pixel and to correct errors caused by atmospheric interactions. Spatial resolution merging and area of interest steps were used. Then, numerous image processing approaches were applied to the Landsat-8 satellite data to identify the various lithological units to display the spatial distribution of the alteration zones.\u003c/p\u003e"},{"header":"4. Results","content":"\u003cdiv id=\"Sec5\" class=\"Section2\"\u003e\n \u003ch2\u003e4.1. Lithological mapping using Landsat-8 data\u003c/h2\u003e\n \u003cdiv id=\"Sec6\" class=\"Section3\"\u003e\n \u003ch2\u003e4.1.1. False color composite (FCC)\u003c/h2\u003e\n \u003cp\u003eThe optimal band triplets for false color composite images were selected using two methods: correlation coefficients (CCs) and the optimum index factor (OIF).\u003c/p\u003e\n \u003cp\u003eThe correlation coefficient method is a statistical approach used to assess the strength of the linear relationship between variables. A smaller correlation coefficient signifies a higher level of variance in the data. By using ENVI image processing software, the correlation coefficient between every two bands was obtained for the seven VNIR-SWIR reflective bands and the correlation matrix (Table \u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003e). The correlation coefficient results revealed a positive correlation between all seven VNIR-SWIR bands. The correlation coefficients for the ten band triplets are presented and ranked in Table \u003cspan class=\"InternalRef\"\u003e2\u003c/span\u003e.\u003c/p\u003e\n \u003cdiv class=\"gridtable\"\u003e\n \u003cdiv class=\"colspec\" align=\"left\"\u003e\u0026nbsp;\u003c/div\u003e\n \u003cdiv class=\"colspec\" align=\"char\"\u003e\u0026nbsp;\u003c/div\u003e\n \u003ctable id=\"Tab1\" border=\"1\"\u003e\n \u003ccaption\u003e\n \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e\n \u003cdiv class=\"CaptionContent\"\u003e\n \u003cp\u003eCorrelation coefficients of Landsat 8 images\u003c/p\u003e\n \u003c/div\u003e\n \u003c/caption\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eBands\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eBand1\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eBand2\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eBand3\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eBand4\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eBand5\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eBand6\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eBand7\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003eBand1\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003eBand2\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.998121\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003eBand3\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.989656\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.992927\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003eBand4\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.968145\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.973071\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.989795\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003eBand5\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.939839\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.945918\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.96826\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.992534\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003eBand6\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.906028\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.911217\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.936791\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.956796\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.964928\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003eBand7\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.896672\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.900558\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.923468\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.937092\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.940756\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.980317\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003c/table\u003e\n \u003c/div\u003e\n \u003cdiv class=\"gridtable\"\u003e\n \u003cdiv class=\"colspec\" align=\"left\"\u003e\u0026nbsp;\u003c/div\u003e\n \u003cdiv class=\"colspec\" align=\"char\"\u003e\u0026nbsp;\u003c/div\u003e\n \u003cdiv class=\"colspec\" align=\"char\"\u003e\u0026nbsp;\u003c/div\u003e\n \u003ctable id=\"Tab2\" border=\"1\"\u003e\n \u003ccaption\u003e\n \u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e\n \u003cdiv class=\"CaptionContent\"\u003e\n \u003cp\u003eRanking of the top ten band triplets for Landsat 8 data in the study area was performed using the correlation coefficient method.\u003c/p\u003e\n \u003c/div\u003e\n \u003c/caption\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eBand Triplet\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eCorrelation coefficients\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eRank\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003e157\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e2.777267\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003e167\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e2.783017\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003e257\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e2.787232\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e3\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003e267\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e2.792092\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e4\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003e127\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e2.795351\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e5\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003e147\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e2.801909\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e6\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003e137\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e2.809796\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e7\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003e247\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e2.810721\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e8\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003e156\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e2.810795\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e9\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003e126\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e2.815366\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e10\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003c/table\u003e\n \u003c/div\u003e\n \u003cp\u003eThe optimum index factor method was developed by Chavez et al. (\u003cspan class=\"CitationRef\"\u003e1982\u003c/span\u003e \u0026amp; \u003cspan class=\"CitationRef\"\u003e1984\u003c/span\u003e). The OIF is a statistical calculation used to evaluate all possible three-band combinations, such as RGB. The OIF values are computed to identify the most favorable band combinations, as described by Cengiz et al. (\u003cspan class=\"CitationRef\"\u003e2006\u003c/span\u003e), and the band triplets are ranked based on the information contained in each combination (Beaudemin and Fung, \u003cspan class=\"CitationRef\"\u003e2001\u003c/span\u003e). The potential for RGB visualization is determined by the total variance and correlation between different bands (Jensen, 1996). Triplets with higher OIF values were selected for better lithological discrimination, as they include bands with maximum variance and minimal redundancy (Qaid and Basavarajappa, 2008). The top ten band triplet combinations are listed in Table \u003cspan class=\"InternalRef\"\u003e3\u003c/span\u003e.\u003c/p\u003e\n \u003cdiv class=\"gridtable\"\u003e\n \u003ctable id=\"Tab3\" border=\"1\"\u003e\n \u003ccaption\u003e\n \u003cdiv class=\"CaptionNumber\"\u003eTable 3\u003c/div\u003e\n \u003cdiv class=\"CaptionContent\"\u003e\n \u003cp\u003eRanking of Landsat 8 Data Obtained Using OIF for the Study Area \u0026nbsp;\u003c/p\u003e\n \u003c/div\u003e\n \u003c/caption\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd width=\"127\"\u003e\n \u003cp\u003e\u003cstrong\u003eBand Triplet\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"156\"\u003e\n \u003cp\u003e\u003cstrong\u003eOIF\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"90\"\u003e\n \u003cp\u003e\u003cstrong\u003eRank\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"127\"\u003e\n \u003cp\u003e\u003cstrong\u003e567\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"156\"\u003e\n \u003cp\u003e0.068248\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"90\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"127\"\u003e\n \u003cp\u003e\u003cstrong\u003e467\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"156\"\u003e\n \u003cp\u003e0.065993\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"90\"\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"127\"\u003e\n \u003cp\u003e\u003cstrong\u003e456\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"156\"\u003e\n \u003cp\u003e0.063795\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"90\"\u003e\n \u003cp\u003e3\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"127\"\u003e\n \u003cp\u003e\u003cstrong\u003e367\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"156\"\u003e\n \u003cp\u003e0.062326\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"90\"\u003e\n \u003cp\u003e4\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"127\"\u003e\n \u003cp\u003e\u003cstrong\u003e457\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"156\"\u003e\n \u003cp\u003e0.062199\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"90\"\u003e\n \u003cp\u003e5\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"127\"\u003e\n \u003cp\u003e\u003cstrong\u003e356\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"156\"\u003e\n \u003cp\u003e0.060376\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"90\"\u003e\n \u003cp\u003e6\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"127\"\u003e\n \u003cp\u003e\u003cstrong\u003e267\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"156\"\u003e\n \u003cp\u003e0.058863\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"90\"\u003e\n \u003cp\u003e7\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"127\"\u003e\n \u003cp\u003e\u003cstrong\u003e357\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"156\"\u003e\n \u003cp\u003e0.05857\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"90\"\u003e\n \u003cp\u003e8\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"127\"\u003e\n \u003cp\u003e\u003cstrong\u003e167\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"156\"\u003e\n \u003cp\u003e0.057951\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"90\"\u003e\n \u003cp\u003e9\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"127\"\u003e\n \u003cp\u003e\u003cstrong\u003e567\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"156\"\u003e\n \u003cp\u003e0.068248\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"90\"\u003e\n \u003cp\u003e10\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003c/table\u003e\n \u003cp\u003eThrough visual inspection of the selected best band triplet possibilities obtained from both the CC and OIF methods, RGB images 7, 5, 1, 7, 6, 2, 7, 2, 1 and 7, 4, 1 in RGB were selected for better lithological discrimination of the exposed rocks in the area (Fig. 3, a,b,c,d)\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/div\u003e\n \u003cdiv class=\"gridtable\"\u003e\u0026nbsp;\u003c/div\u003e\n \u003c/div\u003e\n \u003cdiv id=\"Sec7\" class=\"Section3\"\u003e\n \u003ch2\u003e4.1.2. Principal component analysis (PCA)\u003c/h2\u003e\n \u003cp\u003eThe advantage of PCA (Mohy, \u003cspan class=\"CitationRef\"\u003e2013\u003c/span\u003e; Hegab and Salem, \u003cspan class=\"CitationRef\"\u003e2021\u003c/span\u003e) is that in multispectral data, the majority of the variance is usually concentrated in the first three or four principal component images. Noise tends to accumulate in the less correlated principal components. The first principal component (PC) image captures the most variance and has the lowest correlation, while the last PC image contains the least variance and highest correlation, making the lower-order principal components less useful (e.g., the last principal component image) appear noisy and one cannot identify the features in it clearly.\u003c/p\u003e\n \u003cdiv class=\"gridtable\"\u003e\n \u003ctable id=\"Tab4\" border=\"1\"\u003e\n \u003ccaption\u003e\n \u003cdiv class=\"CaptionNumber\"\u003eTable 4\u003c/div\u003e\n \u003cdiv class=\"CaptionContent\"\u003e\n \u003cp\u003eEigenvector matrix and loading of principal component analysis on Landsat 8 images \u0026nbsp;\u003c/p\u003e\n \u003c/div\u003e\n \u003c/caption\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd width=\"96\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd width=\"72\"\u003e\n \u003cp\u003e\u003cstrong\u003ePC 1\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"72\"\u003e\n \u003cp\u003e\u003cstrong\u003ePC 2\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"72\"\u003e\n \u003cp\u003e\u003cstrong\u003ePC 3\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"72\"\u003e\n \u003cp\u003e\u003cstrong\u003ePC 4\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"72\"\u003e\n \u003cp\u003e\u003cstrong\u003ePC 5\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"72\"\u003e\n \u003cp\u003e\u003cstrong\u003ePC 6\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"111\"\u003e\n \u003cp\u003e\u003cstrong\u003ePC 7\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"96\"\u003e\n \u003cp\u003e\u003cstrong\u003eBand 1\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"72\"\u003e\n \u003cp\u003e-0.94170\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"72\"\u003e\n \u003cp\u003e-0.32103\u003c/p\u003e\n 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\u003cp\u003e0.08302\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"72\"\u003e\n \u003cp\u003e0.00647\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"111\"\u003e\n \u003cp\u003e0.00090\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"96\"\u003e\n \u003cp\u003e\u003cstrong\u003eBand 3\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"72\"\u003e\n \u003cp\u003e0.20250\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"72\"\u003e\n \u003cp\u003e-0.34696\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"72\"\u003e\n \u003cp\u003e0.84898\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"72\"\u003e\n \u003cp\u003e-0.26582\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"72\"\u003e\n \u003cp\u003e0.21518\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"72\"\u003e\n \u003cp\u003e0.00409\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"111\"\u003e\n \u003cp\u003e0.02947\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"96\"\u003e\n \u003cp\u003e\u003cstrong\u003eBand 4\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"72\"\u003e\n \u003cp\u003e-0.05334\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"72\"\u003e\n \u003cp\u003e0.17872\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"72\"\u003e\n \u003cp\u003e-0.16485\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"72\"\u003e\n \u003cp\u003e-0.95084\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"72\"\u003e\n \u003cp\u003e-0.18250\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"72\"\u003e\n \u003cp\u003e-0.01088\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"111\"\u003e\n \u003cp\u003e-0.02274\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"96\"\u003e\n \u003cp\u003e\u003cstrong\u003eBand 5\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"72\"\u003e\n \u003cp\u003e-0.10342\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"72\"\u003e\n \u003cp\u003e0.17392\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"72\"\u003e\n \u003cp\u003e-0.17947\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"72\"\u003e\n \u003cp\u003e-0.11301\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"72\"\u003e\n \u003cp\u003e0.91483\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"72\"\u003e\n \u003cp\u003e0.18942\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"111\"\u003e\n \u003cp\u003e0.20321\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"96\"\u003e\n \u003cp\u003e\u003cstrong\u003eBand 6\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"72\"\u003e\n \u003cp\u003e0.01662\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"72\"\u003e\n \u003cp\u003e-0.03269\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"72\"\u003e\n \u003cp\u003e0.02497\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"72\"\u003e\n \u003cp\u003e0.01515\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"72\"\u003e\n \u003cp\u003e-0.27058\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"72\"\u003e\n \u003cp\u003e0.49285\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"111\"\u003e\n \u003cp\u003e0.82564\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"96\"\u003e\n \u003cp\u003e\u003cstrong\u003eBand 7\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"72\"\u003e\n \u003cp\u003e-0.00873\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"72\"\u003e\n \u003cp\u003e0.00984\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"72\"\u003e\n \u003cp\u003e-0.02296\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"72\"\u003e\n \u003cp\u003e-0.00632\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"72\"\u003e\n \u003cp\u003e0.05106\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"72\"\u003e\n \u003cp\u003e-0.84914\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"111\"\u003e\n \u003cp\u003e0.52499\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"96\"\u003e\n \u003cp\u003e\u003cstrong\u003eEigenvalues\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"72\"\u003e\n \u003cp\u003e\u003cstrong\u003e0.01824\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"72\"\u003e\n \u003cp\u003e\u003cstrong\u003e0.00046\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"72\"\u003e\n \u003cp\u003e\u003cstrong\u003e0.00015\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"72\"\u003e\n \u003cp\u003e\u003cstrong\u003e0.00006\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"72\"\u003e\n \u003cp\u003e\u003cstrong\u003e0.00001\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"72\"\u003e\n \u003cp\u003e\u003cstrong\u003e0.00000\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"111\"\u003e\n \u003cp\u003e\u003cstrong\u003e0.00000\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"96\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd width=\"72\"\u003e\n \u003cp\u003e\u003cstrong\u003e0.96401\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"72\"\u003e\n \u003cp\u003e\u003cstrong\u003e0.02442\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"72\"\u003e\n \u003cp\u003e\u003cstrong\u003e0.00766\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"72\"\u003e\n \u003cp\u003e\u003cstrong\u003e0.00328\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"72\"\u003e\n \u003cp\u003e\u003cstrong\u003e0.00048\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"72\"\u003e\n \u003cp\u003e\u003cstrong\u003e0.00011\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"111\"\u003e\n \u003cp\u003e\u003cstrong\u003e0.00005\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"96\"\u003e\n \u003cp\u003e\u003cstrong\u003e%\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"72\"\u003e\n \u003cp\u003e\u003cstrong\u003e96.40\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"72\"\u003e\n \u003cp\u003e\u003cstrong\u003e2.44\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"72\"\u003e\n \u003cp\u003e\u003cstrong\u003e0.77\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"72\"\u003e\n \u003cp\u003e\u003cstrong\u003e0.33\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"72\"\u003e\n \u003cp\u003e\u003cstrong\u003e0.05\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"72\"\u003e\n \u003cp\u003e\u003cstrong\u003e0.01\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"111\"\u003e\n \u003cp\u003e\u003cstrong\u003e0.01\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003c/table\u003e\n \u003cp\u003eThe principal components were computed from the VNIR and SWIR data bands in the present study. According to the analysis of the eigenvector matrix (Table 4), PC1, 2, 3, and 4 contained almost 99.9% of the information in the data, while the other PC bands contained less than 0.1%. Hence PC3, PC2, and PC1; PC4 and PC2 and PC1 were used, so they contained the most informative data with the highest variance. These data clearly show the relationships between the different rock units and illustrate the general structural features flanking these rocks (Figure 4a, b, c).\u003c/p\u003e\n \u003c/div\u003e\n \u003cdiv class=\"gridtable\"\u003e\u0026nbsp;\u003c/div\u003e\n \u003c/div\u003e\n \u003cdiv id=\"Sec8\" class=\"Section3\"\u003e\n \u003ch2\u003e4.1.3. Color Ratio Composites (CRC)\u003c/h2\u003e\n \u003cp\u003eThis method effectively distinguishes between rock types by highlighting the primary differences in the visible, near-infrared, and shortwave-infrared spectral regions, which are evident along the slopes of the reflectivity curves. The rationing process mitigates first-order brightness effects induced by topographic slopes and accentuates subtle color variations between materials (Abrams et al., \u003cspan class=\"CitationRef\"\u003e1983\u003c/span\u003e).\u003c/p\u003e\n \u003cp\u003eRatio images are generated by dividing the digital number, radiance, or reflectance values of one band by those of another band for each pixel. The resulting ratios are subsequently normalized and visualized as a new ratio image (Sabins, 1997). In the present study, the composite ratios (6/7, 5/6 and 4/2) in RGB were verified to be the optimum mixtures for lithological discrimination and differentiation of the alteration zones from their host rocks (Fig.\u0026nbsp;5). Moreover, various ratios (6/7, 5/2 and 4/5*6/5) were also used for alteration mapping, which mainly revealed yellow to yellowish green colors (Fig.\u0026nbsp;6).\u003c/p\u003e\n \u003cdiv class=\"gridtable\"\u003e\n \u003cdiv class=\"colspec\" align=\"left\"\u003e\u0026nbsp;\u003c/div\u003e\n \u003c/div\u003e\n \u003c/div\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec9\" class=\"Section2\"\u003e\n \u003ch2\u003e4.2. Automatic Lineament Extraction\u003c/h2\u003e\n \u003cp\u003eExtracting lineaments from satellite remotely sensed data for mapping line weakness zones of lineaments faults, joints, cracks, fissures or other linear features is becoming a common automatic process. The importance of mapping linear features is that they represent channels and paths for mineral-bearing hydrothermal solutions. Hydrothermal chemical activity within the surrounding country rocks led to the development of haloes in alteration zones within and around the lineament zones. The types and extensions of these alterations depend on the composition and intensity of such solutions. According to Gupta (\u003cspan class=\"CitationRef\"\u003e2003\u003c/span\u003e), the lineaments represent areas of deformation and higher secondary porosity and are significant channels for fluid migration. Hung et al. (\u003cspan class=\"CitationRef\"\u003e2005\u003c/span\u003e) described lineaments as linear features. Madani and Bishta (\u003cspan class=\"CitationRef\"\u003e2002\u003c/span\u003e) selected the optimal Landsat ETM\u0026thinsp;+\u0026thinsp;bands for automatic lineament extraction and evaluated the relationship between the extracted lineament trends and the presence of uranium in granitic rocks. Mostafa and Bishta (\u003cspan class=\"CitationRef\"\u003e2004\u003c/span\u003e) extracted lineaments from the digital Landsat ETM\u0026thinsp;+\u0026thinsp;for the Gabal Gharib-Dara area using Geo-analyst PCI software. Abo Qudaira (\u003cspan class=\"CitationRef\"\u003e2007\u003c/span\u003e) used SPOT imagery Geomatica PCI Package to extract lineaments Petra-Wadi Al Lahyana area, Jordan. Ghoneim et al. (\u003cspan class=\"CitationRef\"\u003e2022\u003c/span\u003e) derived lineaments from multiple hill shade images with multiple illumination azimuths (0, 45, 90, 135, 180, 225, 270, and 315) that were generated from PAlSAR DEM data via ArcMap v.10.5 software.\u003c/p\u003e\n \u003cp\u003eIn the present research lineament and lineament density maps were extracted from shaded relief images (Figs. 7 and 8) and subsequently correlated and integrated with the obtained alteration information to map the areas with the most potential for mineral exploration. Lineaments are analyzed using density maps (Zakir et al., \u003cspan class=\"CitationRef\"\u003e1999\u003c/span\u003e). There are two main methods for calculating lineament density: counting the number of lineaments per unit area (number/km\u0026sup2;) or summing the lengths of lineaments per unit area (km/km\u0026sup2;). In this study, we used ArcGIS v.10.5 software to calculate lineament density based on the number of lineaments per unit area (number/km\u0026sup2;). The lineament density map (Fig. 8) illustrates the frequency and concentration of lineaments across the study area. Lineaments are analyzed using density maps (Zakir et al., \u003cspan class=\"CitationRef\"\u003e1999\u003c/span\u003e). There are two main methods for calculating lineament density: counting the number of lineaments per unit area (number/km\u0026sup2;) or summing the lengths of lineaments per unit area (km/km\u0026sup2;). In this study, we used ArcGIS v.10.5 software to calculate lineament density based on the number of lineaments per unit area (number/km\u0026sup2;). The lineament density map (Fig.\u0026nbsp;8) illustrates the frequency and concentration of lineaments across the study area.\u003c/p\u003e\n \u003cdiv class=\"gridtable\"\u003e\n \u003cdiv class=\"colspec\" align=\"left\"\u003e\u0026nbsp;\u003c/div\u003e\n \u003c/div\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec10\" class=\"Section2\"\u003e\n \u003ch2\u003e4.3. Alteration mapping using ASTER data\u003c/h2\u003e\n \u003cdiv id=\"Sec11\" class=\"Section3\"\u003e\n \u003ch2\u003e4.3.1. Spectral ratio indices (SRIs)\u003c/h2\u003e\n \u003cp\u003eSeveral mineralogical spectral ratio indices have been proposed by Hewson et al. (\u003cspan class=\"CitationRef\"\u003e2001\u003c/span\u003e) and Ninomiya (\u003cspan class=\"CitationRef\"\u003e2003\u003c/span\u003e) to map alteration zones and associated altered minerals, where altered minerals are present. In this study, the OHI, KLI, and CLI indices, in addition to the iron oxide indices of b2/b1, were applied for alteration mapping. The interpretations of such applications reveal that the distributions of OH-bearing, kaolinite, and iron oxide minerals are associated mainly with acidic rocks (Fig.\u0026nbsp;9). Where OHI is the index of the OH-bearing minerals, KLI is the index of kaolinite minerals, and CLI is the index of calcite minerals.\u003c/p\u003e\n \u003cdiv class=\"gridtable\"\u003e\n \u003cdiv class=\"colspec\" align=\"left\"\u003e\u0026nbsp;\u003c/div\u003e\n \u003c/div\u003e\n \u003c/div\u003e\n \u003cdiv id=\"Sec12\" class=\"Section3\"\u003e\n \u003ch2\u003e4.3.2. Constrained Energy Minimization (CEM)\u003c/h2\u003e\n \u003cp\u003eThe CEM method focuses on the spectral response of specific features while suppressing the responses of other features, treating them as unknown backgrounds. In this study, the CEM method of ASTER VNIR-SWIR surface reflectance data enabled the identification and mapping of the distributions of the most dominant altered minerals montmorillonite, sericite, illite, alunite, and kaolinite (Fig.\u0026nbsp;10). The altered clay minerals were found to be associated with acidic metavolcanics and Dokhan volcanics. Iron oxides and carbonates are mainly present in the western part, where the intermediate metavolcanics and ultramafic rocks are exposed. Sericite and kaolinite are recorded in a belt trending NE‒SW directly to the north of Gabal Abu Qarahish. In the metavolcanics and the older granites northward of Gabal Semna, there are altered minerals, including kaolinite, montmorillonite, and sericite, associated with the alteration zones.\u003c/p\u003e\n \u003cdiv class=\"gridtable\"\u003e\n \u003cdiv class=\"colspec\" align=\"left\"\u003e\u0026nbsp;\u003c/div\u003e\n \u003c/div\u003e\n \u003c/div\u003e\n \u003cdiv id=\"Sec13\" class=\"Section3\"\u003e\n \u003ch2\u003e4.3.3. Crosta principal component analysis (CPCA)\u003c/h2\u003e\n \u003cp\u003eThe studies of Crosta and Moore (1989) have harnessed the power of PCA to unravel the intricate spectral signatures of alteration minerals. Drawing from the extensive resources of the US Geological Survey (USGS) spectral library, these endeavors meticulously identified optimal bands that encapsulate the maximum reflectance and absorption features specific to each alteration mineral. For instance, the spectral behavior of kaolinite is discerned by its pronounced reflectance patterns in bands 4 and 7, juxtaposed with lower reflectance in bands 6 and 9 within the VNIR-SWIR spectral range (Table \u003cspan class=\"InternalRef\"\u003e5\u003c/span\u003e). Such meticulous observations, facilitated by the PCA process using four input bands, culminate in its vivid representation. Similarly, illite, alunite, montmorillonite, and hematite exhibit unique spectral characteristics, all of which are meticulously discerned through the intricate PCA technique.\u003c/p\u003e\n \u003cdiv class=\"gridtable\"\u003e\n \u003cp style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;margin-bottom:12.0pt;text-align:justify;line-height:150%;background:white;'\u003e\u003cstrong\u003e\u003cspan style=\"color:black;\"\u003eTable 5:\u003c/span\u003e\u003c/strong\u003e\u003cspan style=\"color:black;\"\u003e\u0026nbsp;Eigenvector statistics of selected ASTER bands 4, 6, 7 and 9 for kaolinite\u003c/span\u003e\u003c/p\u003e\n \u003ctable style=\"width:466.05pt;margin-left:4.65pt;border-collapse:collapse;border:none;\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 68.35pt;border: 1pt solid windowtext;padding: 0in 5.4pt;height: 15pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003eEigenvector\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 54.95pt;border-top: 1pt solid windowtext;border-right: 1pt solid windowtext;border-bottom: 1pt solid windowtext;border-image: initial;border-left: none;background: yellow;padding: 0in 5.4pt;height: 15pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003eB4\u0026uarr;\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 58.6pt;border-top: 1pt solid windowtext;border-right: 1pt solid windowtext;border-bottom: 1pt solid windowtext;border-image: initial;border-left: none;background: rgb(0, 176, 80);padding: 0in 5.4pt;height: 15pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003eB6\u0026darr;\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 57.15pt;border-top: 1pt solid windowtext;border-right: 1pt solid windowtext;border-bottom: 1pt solid windowtext;border-image: initial;border-left: none;background: yellow;padding: 0in 5.4pt;height: 15pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003eB7\u0026uarr;\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 57.15pt;border-top: 1pt solid windowtext;border-right: 1pt solid windowtext;border-bottom: 1pt solid windowtext;border-image: initial;border-left: none;background: rgb(0, 176, 80);padding: 0in 5.4pt;height: 15pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003eB9\u0026darr;\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 57.15pt;border-top: 1pt solid windowtext;border-right: 1pt solid windowtext;border-bottom: 1pt solid windowtext;border-image: initial;border-left: none;padding: 0in 5.4pt;height: 15pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003eStdev\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 64.2pt;border-top: 1pt solid windowtext;border-right: 1pt solid windowtext;border-bottom: 1pt solid windowtext;border-image: initial;border-left: none;padding: 0in 5.4pt;height: 15pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003eEigenvalue\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 48.5pt;border-top: 1pt solid windowtext;border-right: 1pt solid windowtext;border-bottom: 1pt solid windowtext;border-image: initial;border-left: none;padding: 0in 5.4pt;height: 15pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003eEigen%\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 68.35pt;border-right: 1pt solid windowtext;border-bottom: 1pt solid windowtext;border-left: 1pt solid 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style='font-family:\"Calibri\",sans-serif;color:black;'\u003e0.000067\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 48.5pt;border-top: none;border-left: none;border-bottom: 1pt solid windowtext;border-right: 1pt solid windowtext;padding: 0in 5.4pt;height: 15pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003e0.9\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 68.35pt;border-right: 1pt solid windowtext;border-bottom: 1pt solid windowtext;border-left: 1pt solid windowtext;border-image: initial;border-top: none;padding: 0in 5.4pt;height: 15pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003ePC 4\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 54.95pt;border-top: none;border-left: none;border-bottom: 1pt solid windowtext;border-right: 1pt solid windowtext;background: yellow;padding: 0in 5.4pt;height: 15pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003e-0.16787\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 58.6pt;border-top: none;border-left: none;border-bottom: 1pt solid windowtext;border-right: 1pt solid windowtext;background: rgb(0, 176, 80);padding: 0in 5.4pt;height: 15pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003e-0.30758\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 57.15pt;border-top: none;border-left: none;border-bottom: 1pt solid windowtext;border-right: 1pt solid windowtext;background: yellow;padding: 0in 5.4pt;height: 15pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003e0.211639\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 57.15pt;border-top: none;border-left: none;border-bottom: 1pt solid windowtext;border-right: 1pt solid windowtext;background: rgb(0, 176, 80);padding: 0in 5.4pt;height: 15pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003e-0.91237\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 57.15pt;border-top: none;border-left: none;border-bottom: 1pt solid windowtext;border-right: 1pt solid windowtext;padding: 0in 5.4pt;height: 15pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003e0.007529\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 64.2pt;border-top: none;border-left: none;border-bottom: 1pt solid windowtext;border-right: 1pt solid windowtext;padding: 0in 5.4pt;height: 15pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003e0.00001\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 48.5pt;border-top: none;border-left: none;border-bottom: 1pt solid windowtext;border-right: 1pt solid windowtext;padding: 0in 5.4pt;height: 15pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003e0.2\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003c/table\u003e\n \u003cp style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;margin-top:12.0pt;text-align:justify;line-height:150%;background:white;'\u003e\u003cstrong\u003e\u003cspan style=\"color:black;\"\u003eTable 6:\u003c/span\u003e\u003c/strong\u003e\u003cspan style=\"color:black;\"\u003e\u0026nbsp;Eigenvector statistics of selected ASTER bands 4, 6, 7 and 8 for illite\u003c/span\u003e\u003c/p\u003e\n \u003ctable style=\"width:461.6pt;margin-left:4.65pt;border-collapse:collapse;border:none;\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 68.35pt;border: 1pt solid windowtext;padding: 0in 5.4pt;height: 15pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003eEigenvector\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 56.45pt;border-top: 1pt solid windowtext;border-right: 1pt solid windowtext;border-bottom: 1pt solid windowtext;border-image: initial;border-left: none;background: yellow;padding: 0in 5.4pt;height: 15pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003eB4\u0026uarr;\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 56.45pt;border-top: 1pt solid windowtext;border-right: 1pt solid windowtext;border-bottom: 1pt solid windowtext;border-image: initial;border-left: none;background: rgb(0, 176, 80);padding: 0in 5.4pt;height: 15pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003eB6\u0026darr;\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 56.45pt;border-top: 1pt solid windowtext;border-right: 1pt solid windowtext;border-bottom: 1pt solid windowtext;border-image: initial;border-left: none;background: yellow;padding: 0in 5.4pt;height: 15pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003eB7\u0026uarr;\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 55.9pt;border-top: 1pt solid windowtext;border-right: 1pt solid windowtext;border-bottom: 1pt solid windowtext;border-image: initial;border-left: none;background: rgb(0, 176, 80);padding: 0in 5.4pt;height: 15pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003eB8\u0026darr;\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 56.45pt;border-top: 1pt solid windowtext;border-right: 1pt solid windowtext;border-bottom: 1pt solid windowtext;border-image: initial;border-left: none;padding: 0in 5.4pt;height: 15pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003eStdev\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 63.55pt;border-top: 1pt solid windowtext;border-right: 1pt solid windowtext;border-bottom: 1pt solid windowtext;border-image: initial;border-left: none;padding: 0in 5.4pt;height: 15pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003eEigenvalue\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 48pt;border-top: 1pt solid windowtext;border-right: 1pt solid windowtext;border-bottom: 1pt solid windowtext;border-image: initial;border-left: none;padding: 0in 5.4pt;height: 15pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003eEigen%\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 68.35pt;border-right: 1pt solid windowtext;border-bottom: 1pt solid windowtext;border-left: 1pt solid windowtext;border-image: initial;border-top: none;padding: 0in 5.4pt;height: 15pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003ePC 1\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 56.45pt;border-top: none;border-left: none;border-bottom: 1pt solid windowtext;border-right: 1pt solid windowtext;background: yellow;padding: 0in 5.4pt;height: 15pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003e0.982195\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 56.45pt;border-top: none;border-left: none;border-bottom: 1pt solid windowtext;border-right: 1pt solid windowtext;background: rgb(0, 176, 80);padding: 0in 5.4pt;height: 15pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003e0.090829\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 56.45pt;border-top: none;border-left: none;border-bottom: 1pt solid windowtext;border-right: 1pt solid windowtext;background: yellow;padding: 0in 5.4pt;height: 15pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003e-0.15934\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 55.9pt;border-top: none;border-left: none;border-bottom: 1pt solid windowtext;border-right: 1pt solid windowtext;background: rgb(0, 176, 80);padding: 0in 5.4pt;height: 15pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003e-0.04065\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 56.45pt;border-top: none;border-left: none;border-bottom: 1pt solid windowtext;border-right: 1pt solid windowtext;padding: 0in 5.4pt;height: 15pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003e0.084914\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 63.55pt;border-top: none;border-left: none;border-bottom: 1pt solid windowtext;border-right: 1pt solid windowtext;padding: 0in 5.4pt;height: 15pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003e0.007471\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 48pt;border-top: none;border-left: none;border-bottom: 1pt solid windowtext;border-right: 1pt solid windowtext;padding: 0in 5.4pt;height: 15pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003e97.6\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 68.35pt;border-right: 1pt solid windowtext;border-bottom: 1pt solid windowtext;border-left: 1pt solid windowtext;border-image: initial;border-top: none;padding: 0in 5.4pt;height: 15pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003ePC 2\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 56.45pt;border-top: none;border-left: none;border-bottom: 1pt solid windowtext;border-right: 1pt solid windowtext;background: yellow;padding: 0in 5.4pt;height: 15pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003e0.11263\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 56.45pt;border-top: none;border-left: none;border-bottom: 1pt solid windowtext;border-right: 1pt solid windowtext;background: rgb(0, 176, 80);padding: 0in 5.4pt;height: 15pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003e-0.96656\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 56.45pt;border-top: none;border-left: none;border-bottom: 1pt solid windowtext;border-right: 1pt solid windowtext;background: yellow;padding: 0in 5.4pt;height: 15pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003e0.179984\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 55.9pt;border-top: none;border-left: none;border-bottom: 1pt solid windowtext;border-right: 1pt solid windowtext;background: rgb(0, 176, 80);padding: 0in 5.4pt;height: 15pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003e-0.14381\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 56.45pt;border-top: none;border-left: none;border-bottom: 1pt solid windowtext;border-right: 1pt solid windowtext;padding: 0in 5.4pt;height: 15pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003e0.012498\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 63.55pt;border-top: none;border-left: none;border-bottom: 1pt solid windowtext;border-right: 1pt solid windowtext;padding: 0in 5.4pt;height: 15pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003e0.000098\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 48pt;border-top: none;border-left: none;border-bottom: 1pt solid windowtext;border-right: 1pt solid windowtext;padding: 0in 5.4pt;height: 15pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003e1.3\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 68.35pt;border-right: 1pt solid windowtext;border-bottom: 1pt solid windowtext;border-left: 1pt solid windowtext;border-image: initial;border-top: none;padding: 0in 5.4pt;height: 15pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003ePC 3\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 56.45pt;border-top: none;border-left: none;border-bottom: 1pt solid windowtext;border-right: 1pt solid windowtext;background: yellow;padding: 0in 5.4pt;height: 15pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003e0.13479\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 56.45pt;border-top: none;border-left: none;border-bottom: 1pt solid windowtext;border-right: 1pt solid windowtext;background: rgb(227, 108, 10);padding: 0in 5.4pt;height: 15pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003e0.206267\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 56.45pt;border-top: none;border-left: none;border-bottom: 1pt solid windowtext;border-right: 1pt solid windowtext;background: rgb(227, 108, 10);padding: 0in 5.4pt;height: 15pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003e0.966556\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 55.9pt;border-top: none;border-left: none;border-bottom: 1pt solid windowtext;border-right: 1pt solid windowtext;background: rgb(0, 176, 80);padding: 0in 5.4pt;height: 15pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003e-0.07109\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 56.45pt;border-top: none;border-left: none;border-bottom: 1pt solid windowtext;border-right: 1pt solid windowtext;padding: 0in 5.4pt;height: 15pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003e0.016143\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 63.55pt;border-top: none;border-left: none;border-bottom: 1pt solid windowtext;border-right: 1pt solid windowtext;padding: 0in 5.4pt;height: 15pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003e0.000072\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 48pt;border-top: none;border-left: none;border-bottom: 1pt solid windowtext;border-right: 1pt solid windowtext;padding: 0in 5.4pt;height: 15pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003e0.9\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 68.35pt;border-right: 1pt solid windowtext;border-bottom: 1pt solid windowtext;border-left: 1pt solid windowtext;border-image: initial;border-top: none;padding: 0in 5.4pt;height: 15pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003ePC 4\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 56.45pt;border-top: none;border-left: none;border-bottom: 1pt solid windowtext;border-right: 1pt solid windowtext;background: yellow;padding: 0in 5.4pt;height: 15pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003e-0.06663\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 56.45pt;border-top: none;border-left: none;border-bottom: 1pt solid windowtext;border-right: 1pt solid windowtext;background: rgb(0, 176, 80);padding: 0in 5.4pt;height: 15pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003e0.122327\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 56.45pt;border-top: none;border-left: none;border-bottom: 1pt solid windowtext;border-right: 1pt solid windowtext;background: yellow;padding: 0in 5.4pt;height: 15pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003e-0.08935\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 55.9pt;border-top: none;border-left: none;border-bottom: 1pt solid windowtext;border-right: 1pt solid windowtext;background: rgb(0, 176, 80);padding: 0in 5.4pt;height: 15pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003e-0.98621\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 56.45pt;border-top: none;border-left: none;border-bottom: 1pt solid windowtext;border-right: 1pt solid windowtext;padding: 0in 5.4pt;height: 15pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003e0.005215\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 63.55pt;border-top: none;border-left: none;border-bottom: 1pt solid windowtext;border-right: 1pt solid windowtext;padding: 0in 5.4pt;height: 15pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003e0.000013\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 48pt;border-top: none;border-left: none;border-bottom: 1pt solid windowtext;border-right: 1pt solid windowtext;padding: 0in 5.4pt;height: 15pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003e0.2\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003c/table\u003e\n \u003cp style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;margin-top:12.0pt;text-align:justify;line-height:150%;background:white;'\u003e\u003cstrong\u003e\u003cspan style=\"color:black;\"\u003eTable 7:\u003c/span\u003e\u003c/strong\u003e\u003cspan style=\"color:black;\"\u003e\u0026nbsp;Eigenvector statistics of selected ASTER bands 3, 5, 7 and 9 for alunite\u003c/span\u003e\u003c/p\u003e\n \u003ctable style=\"width:470.65pt;margin-left:4.65pt;border-collapse:collapse;border:none;\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 68.35pt;border: 1pt solid windowtext;padding: 0in 5.4pt;height: 15pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003eEigenvector\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 64.45pt;border-top: 1pt solid windowtext;border-right: 1pt solid windowtext;border-bottom: 1pt solid windowtext;border-image: initial;border-left: none;background: yellow;padding: 0in 5.4pt;height: 15pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003eB3\u0026uarr;\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 56.45pt;border-top: 1pt solid windowtext;border-right: 1pt solid windowtext;border-bottom: 1pt solid windowtext;border-image: initial;border-left: none;background: rgb(0, 176, 80);padding: 0in 5.4pt;height: 15pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003eB5\u0026darr;\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 56.45pt;border-top: 1pt solid windowtext;border-right: 1pt solid windowtext;border-bottom: 1pt solid windowtext;border-image: initial;border-left: none;background: yellow;padding: 0in 5.4pt;height: 15pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003eB7\u0026uarr;\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 56.45pt;border-top: 1pt solid windowtext;border-right: 1pt solid windowtext;border-bottom: 1pt solid windowtext;border-image: initial;border-left: none;background: rgb(0, 176, 80);padding: 0in 5.4pt;height: 15pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003eB9\u0026darr;\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 56.45pt;border-top: 1pt solid windowtext;border-right: 1pt solid windowtext;border-bottom: 1pt solid windowtext;border-image: initial;border-left: none;padding: 0in 5.4pt;height: 15pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003eStdev\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 63.55pt;border-top: 1pt solid windowtext;border-right: 1pt solid windowtext;border-bottom: 1pt solid windowtext;border-image: initial;border-left: none;padding: 0in 5.4pt;height: 15pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003eEigenvalue\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 48.5pt;border-top: 1pt solid windowtext;border-right: 1pt solid windowtext;border-bottom: 1pt solid windowtext;border-image: initial;border-left: none;padding: 0in 5.4pt;height: 15pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003eEigen%\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 68.35pt;border-right: 1pt solid windowtext;border-bottom: 1pt solid windowtext;border-left: 1pt solid windowtext;border-image: initial;border-top: none;padding: 0in 5.4pt;height: 15pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003ePC 1\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 64.45pt;border-top: none;border-left: none;border-bottom: 1pt solid windowtext;border-right: 1pt solid windowtext;background: yellow;padding: 0in 5.4pt;height: 15pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003e0.972396\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 56.45pt;border-top: none;border-left: none;border-bottom: 1pt solid windowtext;border-right: 1pt solid windowtext;background: rgb(0, 176, 80);padding: 0in 5.4pt;height: 15pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003e0.126403\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 56.45pt;border-top: none;border-left: none;border-bottom: 1pt solid windowtext;border-right: 1pt solid windowtext;background: yellow;padding: 0in 5.4pt;height: 15pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003e-0.10135\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 56.45pt;border-top: none;border-left: none;border-bottom: 1pt solid windowtext;border-right: 1pt solid windowtext;background: rgb(0, 176, 80);padding: 0in 5.4pt;height: 15pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003e0.167918\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 56.45pt;border-top: none;border-left: none;border-bottom: 1pt solid windowtext;border-right: 1pt solid windowtext;padding: 0in 5.4pt;height: 15pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003e0.076147\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 63.55pt;border-top: none;border-left: none;border-bottom: 1pt solid windowtext;border-right: 1pt solid windowtext;padding: 0in 5.4pt;height: 15pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003e0.006129\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 48.5pt;border-top: none;border-left: none;border-bottom: 1pt solid windowtext;border-right: 1pt solid windowtext;padding: 0in 5.4pt;height: 15pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003e94.7\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 68.35pt;border-right: 1pt solid windowtext;border-bottom: 1pt solid windowtext;border-left: 1pt solid windowtext;border-image: initial;border-top: none;padding: 0in 5.4pt;height: 15pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003ePC 2\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 64.45pt;border-top: none;border-left: none;border-bottom: 1pt solid windowtext;border-right: 1pt solid windowtext;background: yellow;padding: 0in 5.4pt;height: 15pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003e0.098645\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 56.45pt;border-top: none;border-left: none;border-bottom: 1pt solid windowtext;border-right: 1pt solid windowtext;background: rgb(0, 176, 80);padding: 0in 5.4pt;height: 15pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003e-0.98439\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 56.45pt;border-top: none;border-left: none;border-bottom: 1pt solid windowtext;border-right: 1pt solid windowtext;background: yellow;padding: 0in 5.4pt;height: 15pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003e-0.06548\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 56.45pt;border-top: none;border-left: none;border-bottom: 1pt solid windowtext;border-right: 1pt solid windowtext;background: rgb(0, 176, 80);padding: 0in 5.4pt;height: 15pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003e0.130245\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 56.45pt;border-top: none;border-left: none;border-bottom: 1pt solid windowtext;border-right: 1pt solid windowtext;padding: 0in 5.4pt;height: 15pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003e0.019146\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 63.55pt;border-top: none;border-left: none;border-bottom: 1pt solid windowtext;border-right: 1pt solid windowtext;padding: 0in 5.4pt;height: 15pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003e0.000277\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 48.5pt;border-top: none;border-left: none;border-bottom: 1pt solid windowtext;border-right: 1pt solid windowtext;padding: 0in 5.4pt;height: 15pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003e4.3\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 68.35pt;border-right: 1pt solid windowtext;border-bottom: 1pt solid windowtext;border-left: 1pt solid windowtext;border-image: initial;border-top: none;padding: 0in 5.4pt;height: 15pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003ePC 3\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 64.45pt;border-top: none;border-left: none;border-bottom: 1pt solid windowtext;border-right: 1pt solid windowtext;background: yellow;padding: 0in 5.4pt;height: 15pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003e0.051042\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 56.45pt;border-top: none;border-left: none;border-bottom: 1pt solid windowtext;border-right: 1pt solid windowtext;background: rgb(0, 176, 80);padding: 0in 5.4pt;height: 15pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003e-0.01934\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 56.45pt;border-top: none;border-left: none;border-bottom: 1pt solid windowtext;border-right: 1pt solid windowtext;background: rgb(227, 108, 10);padding: 0in 5.4pt;height: 15pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003e0.953996\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 56.45pt;border-top: none;border-left: none;border-bottom: 1pt solid windowtext;border-right: 1pt solid windowtext;background: rgb(227, 108, 10);padding: 0in 5.4pt;height: 15pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003e0.294808\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 56.45pt;border-top: none;border-left: none;border-bottom: 1pt solid windowtext;border-right: 1pt solid windowtext;padding: 0in 5.4pt;height: 15pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003e0.010675\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 63.55pt;border-top: none;border-left: none;border-bottom: 1pt solid windowtext;border-right: 1pt solid windowtext;padding: 0in 5.4pt;height: 15pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003e0.000054\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 48.5pt;border-top: none;border-left: none;border-bottom: 1pt solid windowtext;border-right: 1pt solid windowtext;padding: 0in 5.4pt;height: 15pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003e0.8\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 68.35pt;border-right: 1pt solid windowtext;border-bottom: 1pt solid windowtext;border-left: 1pt solid windowtext;border-image: initial;border-top: none;padding: 0in 5.4pt;height: 15pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003ePC 4\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 64.45pt;border-top: none;border-left: none;border-bottom: 1pt solid windowtext;border-right: 1pt solid windowtext;background: yellow;padding: 0in 5.4pt;height: 15pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003e0.205209\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 56.45pt;border-top: none;border-left: none;border-bottom: 1pt solid windowtext;border-right: 1pt solid windowtext;background: rgb(0, 176, 80);padding: 0in 5.4pt;height: 15pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003e-0.12096\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 56.45pt;border-top: none;border-left: none;border-bottom: 1pt solid windowtext;border-right: 1pt solid windowtext;background: yellow;padding: 0in 5.4pt;height: 15pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003e0.274464\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 56.45pt;border-top: none;border-left: none;border-bottom: 1pt solid windowtext;border-right: 1pt solid windowtext;background: rgb(0, 176, 80);padding: 0in 5.4pt;height: 15pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003e-0.93163\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 56.45pt;border-top: none;border-left: none;border-bottom: 1pt solid windowtext;border-right: 1pt solid windowtext;padding: 0in 5.4pt;height: 15pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003e0.013904\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 63.55pt;border-top: none;border-left: none;border-bottom: 1pt solid windowtext;border-right: 1pt solid windowtext;padding: 0in 5.4pt;height: 15pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003e0.000013\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 48.5pt;border-top: none;border-left: none;border-bottom: 1pt solid windowtext;border-right: 1pt solid windowtext;padding: 0in 5.4pt;height: 15pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003e0.2\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003c/table\u003e\n \u003cp style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;margin-top:12.0pt;text-align:justify;line-height:150%;background:white;'\u003e\u003cstrong\u003e\u003cspan style=\"color:black;\"\u003eTable 8:\u003c/span\u003e\u003c/strong\u003e\u003cspan style=\"color:black;\"\u003e\u0026nbsp;Eigenvector statistics of selected ASTER bands 3, 6, 7 and 9 for montmorillonite\u003c/span\u003e\u003c/p\u003e\n \u003ctable style=\"width:472.65pt;border-collapse:collapse;border:none;\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 68.35pt;border: 1pt solid windowtext;padding: 0in 5.4pt;height: 15.75pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003eEigenvector\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 58.1pt;border-top: 1pt solid windowtext;border-right: 1pt solid windowtext;border-bottom: 1pt solid windowtext;border-image: initial;border-left: none;background: yellow;padding: 0in 5.4pt;height: 15.75pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003eB3\u0026uarr;\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 58.1pt;border-top: 1pt solid windowtext;border-right: 1pt solid windowtext;border-bottom: 1pt solid windowtext;border-image: initial;border-left: none;background: rgb(0, 176, 80);padding: 0in 5.4pt;height: 15.75pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003eB6\u0026darr;\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 58.1pt;border-top: 1pt solid windowtext;border-right: 1pt solid windowtext;border-bottom: 1pt solid windowtext;border-image: initial;border-left: none;background: yellow;padding: 0in 5.4pt;height: 15.75pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003eB7\u0026uarr;\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 58.1pt;border-top: 1pt solid windowtext;border-right: 1pt solid windowtext;border-bottom: 1pt solid windowtext;border-image: initial;border-left: none;background: rgb(0, 176, 80);padding: 0in 5.4pt;height: 15.75pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003eB9\u0026darr;\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 56.45pt;border-top: 1pt solid windowtext;border-right: 1pt solid windowtext;border-bottom: 1pt solid windowtext;border-image: initial;border-left: none;padding: 0in 5.4pt;height: 15.75pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003eStdev\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 63.55pt;border-top: 1pt solid windowtext;border-right: 1pt solid windowtext;border-bottom: 1pt solid windowtext;border-image: initial;border-left: none;padding: 0in 5.4pt;height: 15.75pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003eEigenvalue\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 51.9pt;border-top: 1pt solid windowtext;border-right: 1pt solid windowtext;border-bottom: 1pt solid windowtext;border-image: initial;border-left: none;padding: 0in 5.4pt;height: 15.75pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003eEigen%\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 68.35pt;border-right: 1pt solid windowtext;border-bottom: 1pt solid windowtext;border-left: 1pt solid windowtext;border-image: initial;border-top: none;padding: 0in 5.4pt;height: 15pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003ePC 1\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 58.1pt;border-top: none;border-left: none;border-bottom: 1pt solid windowtext;border-right: 1pt solid windowtext;background: yellow;padding: 0in 5.4pt;height: 15pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003e0.972406\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 58.1pt;border-top: none;border-left: none;border-bottom: 1pt solid windowtext;border-right: 1pt solid windowtext;background: rgb(0, 176, 80);padding: 0in 5.4pt;height: 15pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003e0.141543\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 58.1pt;border-top: none;border-left: none;border-bottom: 1pt solid windowtext;border-right: 1pt solid windowtext;background: yellow;padding: 0in 5.4pt;height: 15pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003e-0.06403\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 58.1pt;border-top: none;border-left: none;border-bottom: 1pt solid windowtext;border-right: 1pt solid windowtext;background: rgb(0, 176, 80);padding: 0in 5.4pt;height: 15pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003e0.174045\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 56.45pt;border-top: none;border-left: none;border-bottom: 1pt solid windowtext;border-right: 1pt solid windowtext;padding: 0in 5.4pt;height: 15pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003e0.075245\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 63.55pt;border-top: none;border-left: none;border-bottom: 1pt solid windowtext;border-right: 1pt solid windowtext;padding: 0in 5.4pt;height: 15pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003e0.005983\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 51.9pt;border-top: none;border-left: none;border-bottom: 1pt solid windowtext;border-right: 1pt solid windowtext;padding: 0in 5.4pt;height: 15pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003e94.6\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 68.35pt;border-right: 1pt solid windowtext;border-bottom: 1pt solid windowtext;border-left: 1pt solid windowtext;border-image: initial;border-top: none;padding: 0in 5.4pt;height: 15pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003ePC 2\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 58.1pt;border-top: none;border-left: none;border-bottom: 1pt solid windowtext;border-right: 1pt solid windowtext;background: yellow;padding: 0in 5.4pt;height: 15pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003e0.114281\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 58.1pt;border-top: none;border-left: none;border-bottom: 1pt solid windowtext;border-right: 1pt solid windowtext;background: rgb(0, 176, 80);padding: 0in 5.4pt;height: 15pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003e-0.98187\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 58.1pt;border-top: none;border-left: none;border-bottom: 1pt solid windowtext;border-right: 1pt solid windowtext;background: yellow;padding: 0in 5.4pt;height: 15pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003e-0.03487\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 58.1pt;border-top: none;border-left: none;border-bottom: 1pt solid windowtext;border-right: 1pt solid windowtext;background: rgb(0, 176, 80);padding: 0in 5.4pt;height: 15pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003e0.147178\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 56.45pt;border-top: none;border-left: none;border-bottom: 1pt solid windowtext;border-right: 1pt solid windowtext;padding: 0in 5.4pt;height: 15pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003e0.019331\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 63.55pt;border-top: none;border-left: none;border-bottom: 1pt solid windowtext;border-right: 1pt solid windowtext;padding: 0in 5.4pt;height: 15pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003e0.000263\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 51.9pt;border-top: none;border-left: none;border-bottom: 1pt solid windowtext;border-right: 1pt solid windowtext;padding: 0in 5.4pt;height: 15pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003e4.2\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 68.35pt;border-right: 1pt solid windowtext;border-bottom: 1pt solid windowtext;border-left: 1pt solid windowtext;border-image: initial;border-top: none;padding: 0in 5.4pt;height: 15pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003ePC 3\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 58.1pt;border-top: none;border-left: none;border-bottom: 1pt solid windowtext;border-right: 1pt solid windowtext;background: yellow;padding: 0in 5.4pt;height: 15pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003e0.028821\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 58.1pt;border-top: none;border-left: none;border-bottom: 1pt solid windowtext;border-right: 1pt solid windowtext;background: rgb(0, 176, 80);padding: 0in 5.4pt;height: 15pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003e-0.00139\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 58.1pt;border-top: none;border-left: none;border-bottom: 1pt solid windowtext;border-right: 1pt solid windowtext;background: rgb(227, 108, 10);padding: 0in 5.4pt;height: 15pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003e0.979289\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 58.1pt;border-top: none;border-left: none;border-bottom: 1pt solid windowtext;border-right: 1pt solid windowtext;background: rgb(227, 108, 10);padding: 0in 5.4pt;height: 15pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003e0.200399\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 56.45pt;border-top: none;border-left: none;border-bottom: 1pt solid windowtext;border-right: 1pt solid windowtext;padding: 0in 5.4pt;height: 15pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003e0.009408\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 63.55pt;border-top: none;border-left: none;border-bottom: 1pt solid windowtext;border-right: 1pt solid windowtext;padding: 0in 5.4pt;height: 15pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003e0.000066\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 51.9pt;border-top: none;border-left: none;border-bottom: 1pt solid windowtext;border-right: 1pt solid windowtext;padding: 0in 5.4pt;height: 15pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003e1\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 68.35pt;border-right: 1pt solid windowtext;border-bottom: 1pt solid windowtext;border-left: 1pt solid windowtext;border-image: initial;border-top: none;padding: 0in 5.4pt;height: 15pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003ePC 4\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 58.1pt;border-top: none;border-left: none;border-bottom: 1pt solid windowtext;border-right: 1pt solid windowtext;background: yellow;padding: 0in 5.4pt;height: 15pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003e-0.20133\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 58.1pt;border-top: none;border-left: none;border-bottom: 1pt solid windowtext;border-right: 1pt solid windowtext;background: rgb(0, 176, 80);padding: 0in 5.4pt;height: 15pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003e0.1261\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 58.1pt;border-top: none;border-left: none;border-bottom: 1pt solid windowtext;border-right: 1pt solid windowtext;background: yellow;padding: 0in 5.4pt;height: 15pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003e-0.18888\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 58.1pt;border-top: none;border-left: none;border-bottom: 1pt solid windowtext;border-right: 1pt solid windowtext;background: rgb(0, 176, 80);padding: 0in 5.4pt;height: 15pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003e0.952831\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 56.45pt;border-top: none;border-left: none;border-bottom: 1pt solid windowtext;border-right: 1pt solid windowtext;padding: 0in 5.4pt;height: 15pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003e0.014152\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 63.55pt;border-top: none;border-left: none;border-bottom: 1pt solid windowtext;border-right: 1pt solid windowtext;padding: 0in 5.4pt;height: 15pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003e0.000012\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 51.9pt;border-top: none;border-left: none;border-bottom: 1pt solid windowtext;border-right: 1pt solid windowtext;padding: 0in 5.4pt;height: 15pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003e0.2\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003c/table\u003e\n \u003c/div\u003e\n \u003cp style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;margin-top:12.0pt;text-align:justify;line-height:150%;background:white;'\u003e\u003cstrong\u003e\u003cspan style=\"color:black;\"\u003eTable 9:\u003c/span\u003e\u003c/strong\u003e\u003cspan style=\"color:black;\"\u003e\u0026nbsp;Eigenvector statistics of selected ASTER bands 2, 3, 4 and 9 for iron oxides\u003c/span\u003e\u003c/p\u003e\n \u003ctable style=\"width:462.15pt;margin-left:4.65pt;border-collapse:collapse;border:none;\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 68.35pt;border: 1pt solid windowtext;padding: 0in 5.4pt;height: 15pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003eEigenvector\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 56.45pt;border-top: 1pt solid windowtext;border-right: 1pt solid windowtext;border-bottom: 1pt solid windowtext;border-image: initial;border-left: none;background: yellow;padding: 0in 5.4pt;height: 15pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003eB2\u0026uarr;\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 56.45pt;border-top: 1pt solid windowtext;border-right: 1pt solid windowtext;border-bottom: 1pt solid windowtext;border-image: initial;border-left: none;background: rgb(0, 176, 80);padding: 0in 5.4pt;height: 15pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003eB3\u0026darr;\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 56.45pt;border-top: 1pt solid windowtext;border-right: 1pt solid windowtext;border-bottom: 1pt solid windowtext;border-image: initial;border-left: none;background: yellow;padding: 0in 5.4pt;height: 15pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003eB4\u0026uarr;\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 56.45pt;border-top: 1pt solid windowtext;border-right: 1pt solid windowtext;border-bottom: 1pt solid windowtext;border-image: initial;border-left: none;background: rgb(0, 176, 80);padding: 0in 5.4pt;height: 15pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003eB9\u0026darr;\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 56.45pt;border-top: 1pt solid windowtext;border-right: 1pt solid windowtext;border-bottom: 1pt solid windowtext;border-image: initial;border-left: none;padding: 0in 5.4pt;height: 15pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003eStdev\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 63.55pt;border-top: 1pt solid windowtext;border-right: 1pt solid windowtext;border-bottom: 1pt solid windowtext;border-image: initial;border-left: none;padding: 0in 5.4pt;height: 15pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003eEigenvalue\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 48pt;border-top: 1pt solid windowtext;border-right: 1pt solid windowtext;border-bottom: 1pt solid windowtext;border-image: initial;border-left: none;padding: 0in 5.4pt;height: 15pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003eEigen%\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 68.35pt;border-right: 1pt solid windowtext;border-bottom: 1pt solid windowtext;border-left: 1pt solid windowtext;border-image: initial;border-top: none;padding: 0in 5.4pt;height: 15pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003ePC 1\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 56.45pt;border-top: none;border-left: none;border-bottom: 1pt solid windowtext;border-right: 1pt solid windowtext;background: yellow;padding: 0in 5.4pt;height: 15pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003e0.963953\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 56.45pt;border-top: none;border-left: none;border-bottom: 1pt solid windowtext;border-right: 1pt solid windowtext;background: rgb(0, 176, 80);padding: 0in 5.4pt;height: 15pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003e0.090142\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 56.45pt;border-top: none;border-left: none;border-bottom: 1pt solid windowtext;border-right: 1pt solid windowtext;background: yellow;padding: 0in 5.4pt;height: 15pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003e-0.24649\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 56.45pt;border-top: none;border-left: none;border-bottom: 1pt solid windowtext;border-right: 1pt solid windowtext;background: rgb(0, 176, 80);padding: 0in 5.4pt;height: 15pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003e0.043718\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 56.45pt;border-top: none;border-left: none;border-bottom: 1pt solid windowtext;border-right: 1pt solid windowtext;padding: 0in 5.4pt;height: 15pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003e0.083281\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 63.55pt;border-top: none;border-left: none;border-bottom: 1pt solid windowtext;border-right: 1pt solid windowtext;padding: 0in 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Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003ePC 4\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 56.45pt;border-top: none;border-left: none;border-bottom: 1pt solid windowtext;border-right: 1pt solid windowtext;background: yellow;padding: 0in 5.4pt;height: 15pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003e-0.06487\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 56.45pt;border-top: none;border-left: none;border-bottom: 1pt solid windowtext;border-right: 1pt solid windowtext;background: rgb(0, 176, 80);padding: 0in 5.4pt;height: 15pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003e0.003844\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 56.45pt;border-top: none;border-left: none;border-bottom: 1pt solid windowtext;border-right: 1pt solid windowtext;background: yellow;padding: 0in 5.4pt;height: 15pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003e-0.07582\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 56.45pt;border-top: none;border-left: none;border-bottom: 1pt solid windowtext;border-right: 1pt solid windowtext;background: rgb(0, 176, 80);padding: 0in 5.4pt;height: 15pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003e0.995001\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 56.45pt;border-top: none;border-left: none;border-bottom: 1pt solid windowtext;border-right: 1pt solid windowtext;padding: 0in 5.4pt;height: 15pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003e0.005696\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 63.55pt;border-top: none;border-left: none;border-bottom: 1pt solid windowtext;border-right: 1pt solid windowtext;padding: 0in 5.4pt;height: 15pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003e0.000018\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 48pt;border-top: none;border-left: none;border-bottom: 1pt solid windowtext;border-right: 1pt solid windowtext;padding: 0in 5.4pt;height: 15pt;vertical-align: bottom;\"\u003e\n \u003cp dir=\"RTL\" style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cspan dir=\"LTR\" style='font-family:\"Calibri\",sans-serif;color:black;'\u003e0.2\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003c/table\u003e\n \u003c/div\u003e\n \u003cdiv class=\"gridtable\"\u003e\u003cbr\u003e\u003c/div\u003e\n \u003cp\u003eKaolinite exhibits significant reflectance characteristics in bands 4 and 7, with notably lower reflectances in bands 6 and 9 within the VNIR-SWIR spectral region. These spectral bands were subjected to principal component analysis (PCA), which yielded four principal components (PCs), as detailed in Table \u003cspan class=\"InternalRef\"\u003e5\u003c/span\u003e. PC2 demonstrated the highest positive loadings from band 7 (0.924177) and band 9 (0.298472), resulting in the representation of kaolinite as blue in the resultant image. Similarly, illite displays pronounced reflectance in bands 4 and 7, alongside reduced reflectance in bands 6 and 8. The PCA conducted with these bands, as summarized in Table \u003cspan class=\"InternalRef\"\u003e6\u003c/span\u003e, revealed that PC3 exhibited the highest loadings from band 7 (0.966556) and band 6 (0.206267), depicting illite as yellow in the resultant imagery. Alunite is characterized by high reflectance in bands 3 and 7 coupled with low reflectance in bands 5 and 9. The PCA results presented in Table indicate that PC3 displayed significant positive loadings from band 7 (0.953996) and band 9 (0.294808), indicating that the alunite was a large sky (red). Montmorillonite similarly shows high reflectance in bands 3 and 7, with low reflectance in bands 6 and 9. PCA outlined in Table \u003cspan class=\"InternalRef\"\u003e8\u003c/span\u003e, revealed that PC3 exhibited high positive loadings from band 7 (0.979289) and band 9 (0.200399), resulting in the representation of montmorillonite as green. Hematite has high reflectance in bands 2 and 4 and low reflectance in bands 3 and 9. The PCA of these bands, detailed in Table \u003cspan class=\"InternalRef\"\u003e9\u003c/span\u003e, indicated that PC2 had high positive loadings from band 3 (0.918021) and band 4 (0.395329), resulting in hematite being depicted as brown in the final image. The application of the CPCA method to ASTER data for mapping altered minerals revealed significant spatial coincidence among these minerals. This analysis effectively delineated alteration zones (Fig. 11) that could be used for gold exploration at Gabal Semna and Gabal Abu Karahish, providing critical insights for targeted geological assessments.\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec14\" class=\"Section2\"\u003e\n \u003ch2\u003e4.4. Spatial relation between the lineaments and alterations\u003c/h2\u003e\n \u003cp\u003eThe obtained lineament density map was correlated with the provided altered mineral abundance map, which revealed an intimate spatial relation where dense lineaments are confined by the location and distribution of alteration zones. The results of such integration revealed several alteration zones regarded as potentially high-elevation areas for mineral exploration. The known Semna and Abu Qarahish mine areas are delineated areas (Fig.\u0026nbsp;12).\u003c/p\u003e\n \u003cdiv class=\"gridtable\"\u003e\n \u003cdiv class=\"colspec\" align=\"left\"\u003e\u0026nbsp;\u003c/div\u003e\n \u003c/div\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec15\" class=\"Section2\"\u003e\n \u003ch2\u003e4.5. Field verification\u003c/h2\u003e\n \u003cp\u003eSome field visits have been assumed to verify the results from remote sensing and to locate structurally controlled alteration zones and associated altered minerals. Moreover selective samples were collected from the quartz veins and alteration zones of various rocks for SEM analysis and gold detection (Fig. 13).\u003c/p\u003e\n \u003cp\u003eIn the Gabal Abu Karahish area, the metavolcanics are partly overthrusted by serpentinite and talc carbonate masses, where several alterations in iron carbonate and silica (listwanite ridges) developed along contacts with the metavolcanics, forming a valid geological environment for gold exploration. The metavolcanics intrude younger granite plutons and several felsite sheets and plugs in the Gabal Abu Qarahish, Gabal Wae\u0026rsquo;ra and Gabal Kab Amiri areas (Fig. 14). Moreover, the gabbroic and older granitic plutons intrude the acidic metavolcanics and ultramafics in the northern Gabal Semna area. Near the intrusions in the metavolcanics, there are several quartz veins, veinlets, plugs and offshoots of milky and smoky type crosscutting the country rocks of different sizes with varied trends; they are enriched in sulfides and iron oxides, which may enclose gold.\u003c/p\u003e\n \u003cp\u003eTen samples from the altered zones, quartz veins, and country rocks were exposed via electron microscopy (SEM) to detect and assess the gold content and related elements in the study area. All the rock samples contained less than 1% Au in a total bulk of 50 grams for each crushed sample. The analyzed samples have gold contents ranging from 0.08\u0026ndash;0.83% and silver contents ranging from 0.01\u0026ndash;0.10% (Fig. 15). Sample 2 from the altered metavolcanics contains the highest gold value of 0.83% Au ppm, while Sample 5 from the altered metavolcanics also has a lower Au content of 0.08 Au ppm. The gold is mainly hosted in pyrie and arsenpyrite crystals and is associated with the following elements at different percentages and randomly related to gold. However, a reverse relationship between gold and Si% is shown in most samples due to the alteration and increase in clay minerals at the expense of silica. The copper (Cu) content ranged from 0.02\u0026ndash;2.07%, the aluminum (Al) content ranged from 0.44\u0026ndash;11.19%, the oxygen (O) content ranged from 30.74\u0026ndash;53.79%, the carbon (C) content ranged from 10.97\u0026ndash;41.42%, the calcium (Ca) content ranged from 1.07\u0026ndash;6.19%, the silicon (Si) content ranged from 6.19\u0026ndash;40.02%, the iron (Fe) content ranged from 1.10\u0026ndash;35.21%, and the hafnium (Hf) content ranged from 0.03\u0026ndash;0.28%.\u003c/p\u003e\n \u003cdiv class=\"gridtable\"\u003e\n \u003cdiv class=\"colspec\" align=\"left\"\u003e\u0026nbsp;\u003c/div\u003e\n \u003cdiv class=\"colspec\" align=\"left\"\u003eIn the alteration zones, a relatively greater percentage of gold is found in the alteration zones than in the country rocks, and more or less than in the quartz veins. In the studied altered zones, silver and copper are frequently connected to gold. Ilmenite, rutile, cobaltite, and barite are occasionally found along with sulfides and iron oxides (the host minerals of gold). The contents of Au, Ag, and their related elements are comparatively high in the altered and quartz vein samples.\u003c/div\u003e\n \u003c/div\u003e\n\u003c/div\u003e"},{"header":"5. Discussion","content":"\u003cp\u003eExploring new gold fields in the alteration zones of the areas surrounding the Gabal Abu Karahish and Semna mines is the goal of this study. For this purpose, enhanced mapping of lithological units was necessary for mapping alteration zones as target areas for gold exploration. In this way, several remote sensing techniques were useful for obtaining Landsat-8 satellite and ASTER data for accurate geological and alteration mapping. Moreover, geological field verification and SEM analysis were performed to support the existence and localization of the alteration zones and their gold potentiality in the study area. The granitic and gabbroic intrusions in the country rocks are mainly associated with mineral-bearing hydrothermal fluids and residual silica that percolate and ascend through rock lineaments and fractures. The chemical activity and metasomatism of the solutions to the surrounding rocks leave marks of alteration hallows with altered and valued mineral precipitation along the hydrothermal flowing zones. Moreover, sulfide-bearing quartz veins and associated hydrothermal breccia bodies exhibit a variety of textures, including sheared, badinage, and recrystallized quartz, as well as open-space filling and micro breccia within the alteration zones. These textures indicate a complex crack-seal mechanism that highlights the interaction between mineral deposition and a significant N–S-trending shear zone. This relationship is a result of a late brittle–ductile deformation event that impacted the area approximately 550\u0026nbsp;million years ago. These alteration zones, characterized by variable textures, are promising targets for gold exploration. The automatic extraction of the lineaments was also implemented in the localization of the alteration zones, where the rock lineaments represent zones of deformation that imply secondary porosity as channels for the migration of hydrothermal solutions that help in forming and developing alteration zones along their paths. Moreover, the alteration and lineament data were integrated to delineate the most potential localities for gold exploration, where the special distribution and density of the extracted lineaments are mainly coincident and correlated with the presence of alteration zones and altered minerals in the study area.\u003c/p\u003e \u003cp\u003eZoheir et al. (2008) reported that at a temperature of approximately 250°C and pressure of 2.3 kbars, shear zones, and associated alteration zones, combined with the upward migration of hydrothermal fluids, led to a pressure drop. This pressure drop caused the separation of an aqueous phase and a carbonic phase. The resulting alteration assemblage includes quartz, chlorite, pyrite, calcite, and possibly epidote, with pervasive silicification, pyritization, sericitization, and carbonatization processes contributing to hydrothermal alteration. Additionally, sets of quartz veins and altered shears are significant indicators of hydrothermal alteration. Azizi (2010) and Salem et al. (\u003cspan citationid=\"CR87\" class=\"CitationRef\"\u003e2016\u003c/span\u003e) used SWIR ASTER data to identify alteration zones in the Barramiya district of Egypt and the eastern Zanjan district in northern Iran, respectively. In the El Sid gold mine area, following the emplacement of granite, hydrothermal fluids interacted with sheared serpentinite. These interactions led to metal leaching and re-deposition in adjacent wall rocks and faults through cyclic processes (Helmi and Zoheir, 2014; Ghoneim, 2019, 2020).\u003c/p\u003e \u003cp\u003eAlteration zones in the study area were mapped using various remote sensing approaches, including spectral ratio indices (SRIs), constrained energy minimization (CEM), and Crosta principal component analysis (CPCA). The results from fieldwork and SEM analysis corroborated these remote sensing findings. Specifically, the alteration zones identified using ASTER data were verified through field observations, confirming their locations and association with gold mineralization.\u003c/p\u003e "},{"header":"Conclusion","content":"\u003cp\u003eThe VNIR and SWIR bands of ASTER provide highly accurate data for detecting even limited and restricted alteration zones, making ASTER data extremely effective for mapping alteration zones and altered minerals. Band math formulas such as (b7 + b9)/b8 (b7 + b9)/b8 (b7 + b9)/b8 are useful for identifying carbonate, chlorite, and epidote minerals, while (b5 + b7)/b6 (b5 + b7) b6(b5 + b7)/b6 help illustrate confined sericite and clay minerals, which are indicative of gold occurrences. A band ratio of 4/54/54/5 is particularly effective for detailed mapping of alteration zones.\u003c/p\u003e\u003cp\u003eRemote sensing techniques such as the SAM, SFF, CEM, and MTMF are the most effective for mapping the spatial distribution of endmembers using ASTER satellite data. This study identifies gold occurrences in two main altered geological environments: 1) altered listennites, 2) altered pyritized metavolcanics, and 3) crosscutting quartz veins in the country rocks. These alterations, including sericitization, chloritization, silicification, and carbonization, are linked to fracture fillings and are readily identifiable on the surface.\u003c/p\u003e\u003cp\u003eLarge areas of intense alteration in the ultramafic and metavolcanic rocks of the Gabal Abu Karahish and Gabal Semna areas suggest potential sites for gold mineralization. SEM analysis, which showed that all the analyzed samples contained approximately 1% gold by bulk (approximately 50 grams per sample), supported this potential. The methodologies used, particularly the SRI and CEM, demonstrated a high degree of confidence and are recommended for alteration mapping in similar areas.\u003c/p\u003e\u003cp\u003eFurther detailed exploration is advised to maximize the use of the identified mineral resources, as the delineated potentially mineralized sites have been validated in the field and present promising targets for gold exploration.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e \u003cstrong\u003eConflict of interest:\u003c/strong\u003e \u003cp\u003eThe authors have no financial or personal interests that could have influenced the results or interpretation of this research.\u003c/p\u003e \u003c/p\u003e\u003ch2\u003eFunding:\u003c/h2\u003e \u003cp\u003eWe did not receive any funding for this study.\u003c/p\u003e\u003ch2\u003eAuthors Contributions:\u003c/h2\u003e \u003cp\u003eEach author played a key role in the study, from designing and conducting the research to analyzing the data and writing the manuscript.\u003c/p\u003e\u003ch2\u003eData availability:\u003c/h2\u003e \u003cp\u003eIf you are interested in the data from this study, please contact the corresponding author. The data will be shared upon reasonable request.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eAbo Qudaira MA (2007) Utilization of remote sensing and GIS techniques in geological mapping, lineaments extraction, and minerals exploration along the eastern part of centeral Wadi Araba, Southwest Jordan. M.Sc. thesis, Cairo University, Egypt, p. 230\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eAbou El-Magd I, Mohy H, Basta F (2015) Application of remote sensing for gold exploration in the Fawakhir area, Central Eastern Desert of Egypt. 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Egypt J Afr Earth Sci 66(67):22\u0026ndash;34\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":true,"hideJournal":true,"highlight":"","institution":"National Authority for Remote Sensing and Space Sciences","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"Remote sensing, ASTER, Alteration zones, Abu Karahish area","lastPublishedDoi":"10.21203/rs.3.rs-5148766/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-5148766/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eThis study focuses on exploring the presence and distribution of gold deposits in the Gabal Abu Karahish area, where volcanic and plutonic rocks and structural settings form valid geological environments for mineral exploration due to mineral-bearing hydrothermal activity in tectonized areas. Various tools have been integrated to determine gold potential and availability in this are In addition, for ASTER image processing band ratios 7/6_4/6 and 7/8, radiometric data, field geology, and spectral measurements of the specific rocks were combined to differentiate the alteration zones as promised localities for gold exploration. Several alteration zones of argellic, phyllic, and propylitic alteration types have been developed and localized. They are mainly associated with altered minerals such as chlorite, calcite, kaolinite, sericite, carbonates, and iron oxides. Scanning electron microscopy (SEM) images of ten representative samples from the alteration zones and quartz veins in the meavolcanics and ultramafics revealed that gold is present in all samples at average contents between 0.23 and 0.83 (from a bulk of 50 g of rock powder). These results indicate and suggest promising alteration zones for gold exploration. The study area consists of calc-alkaline metavolcanic rocks and younger Dokhan volcanic rocks. The metavolcanics are overthrusted by slices of serpentinites and talc carbonates, where some listwanite ridges (iron carbonate silica) developed along such contacts. Hornblende gabbros are present in small outcrops to the northeast of Gabal Abu Qarahish. Tonalite and granodiorite rocks are found in several localities, with most outcropsrecorded at Gabal Semna, where younger granite plutons intruded into the metavolcanics and surrounding rocks. The Dokhan volcanic sequence, composed mostly of quartz-feldspar porphyrite and andesite porphyry, is interlayered with siltstone, mudstone, and polymictic conglomerates typical of molasse-type Hammamat sediments.\u003c/p\u003e","manuscriptTitle":"Gold exploration in the Gabal Abu Karahish area, Central Eastern Desert, Egypt, using remote sensing and analytical techniques","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2024-10-01 12:43:25","doi":"10.21203/rs.3.rs-5148766/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"606987b8-1b79-45fd-b8ba-f11f4d7ea8dd","owner":[],"postedDate":"October 1st, 2024","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[{"id":38164596,"name":"Geology"}],"tags":[],"updatedAt":"2024-10-01T12:43:26+00:00","versionOfRecord":[],"versionCreatedAt":"2024-10-01 12:43:25","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-5148766","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-5148766","identity":"rs-5148766","version":["v1"]},"buildId":"qtupq5eGEP_6zYnWcrvyt","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}