Geology and Structure of Uru-Ugworji Diorite Lokpanukwu, Southeastern Nigeria

Geological, Geophysical and Core analyses were carried out in Uru Quarry site, Lokpaukwu located between latitudes 5056.149’N and 5056.193’N and between 7028.312’E and 7028.356’E. Geologic formations that underlie the study area are the Asu River Group and Eze-Aku Formation. Five rock units are found in the area; siltstone found in the eastern portion of the study area and occurs as a “CAP” on the shale. The middle portion of the study area is underlain by shale, and it occupies one-half of the study area. Calcareous sandstone occupies the Western portion of the area. The Eastern portion is Dolerite which is the basic rock matter that cuts across siltstone and shale. Iron is found with the basic rock matter in the area. Geological studies on the study area indicate the five rock units and their outcrops; 2 geological sections were interpreted. Geophysical methods using the Electrical Resistivity Sounding of Schlumberger indicates the West, Northwestern and Central portions of the area have thick sedimentary sequence and the Eastern portion of the study area is made up of igneous body which is the main part of this project; the basic rock having a high resistivity value, followed by sandstone, siltstone and shale with moderate to low resistivity. Core analysis carried on eleven core samples obtained at the Eastern portion of the study area shows that the core samples consist of the rock unit found in the area. In the Obichioke area were nine core samples consisting of rock units too. Core data analysis of the study area indicates the location and kind of rocks found in the study area; mineral present and the strength of the rock units found in Lokpaukwu area. Geologic mapping shows that a major fault occur in the area separating the viable Uru end from the non-viable Obichioke lot. The fault trace shows primarily recrystallization (alcitic matter). Thus, it is suggested that similar studies be made before the establishment of quarries whenever igneous (basic) units occur.