Creating a Critical Zone: Feedbacks Between Bedrock Geology, Hydrology, and Vegetation on an Exposed Bedrock Surface, Panola Mountain, Georgia, USA

Creating a Critical Zone: Feedbacks Between Bedrock Geology, Hydrology, and Vegetation on an Exposed Bedrock Surface, Panola Mountain, Georgia, USA | Authorea try { document.documentElement.classList.add('js'); } catch (e) { } var _gaq = _gaq || []; _gaq.push(['_setAccount', 'G-8VDV14Y67G']); _gaq.push(['_trackPageview']); (function() { var ga = document.createElement('script'); ga.type = 'text/javascript'; ga.async = true; ga.src = ('https:' == document.location.protocol ? 'https://ssl' : 'http://www') + '.google-analytics.com/ga.js'; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(ga, s); })(); Skip to main content Preprints Collections Wiley Open Research IET Open Research Ecological Society of Japan All Collections About About Authorea FAQs Contact Us Quick Search anywhere Search for preprint articles, keywords, etc. Search Search ADVANCED SEARCH SCROLL This is a preprint and has not been peer reviewed. Data may be preliminary. 26 February 2026 V2 Latest version Share on Creating a Critical Zone: Feedbacks Between Bedrock Geology, Hydrology, and Vegetation on an Exposed Bedrock Surface, Panola Mountain, Georgia, USA Authors : Sean P. Bemis 0000-0001-7854-6394 [email protected] , W. Steven Holbrook 0000-0003-0065-8841 , Brady A Flinchum 0000-0003-0395-0450 , Jorden L Hayes 0000-0001-5967-3953 , Russell P Callahan 0000-0002-0091-3446 , Ciaran J Harman 0000-0002-3185-002X , Bradley J. Carr 0000-0002-1378-4911 , and Clifford S. Riebe 0000-0002-8744-8208 Authors Info & Affiliations https://doi.org/10.22541/au.174405192.22137346/v2 371 views 301 downloads Contents Abstract Supplementary Material Information & Authors Metrics & Citations View Options References Figures Tables Media Share Abstract This preprint is the original submitted manuscript. The final published version is available open-access in the Journal of Geophysical Research: Earth Surface at: doi.org/10.1029/2025JF008424 Most of Earth's present-day terrestrial surface is covered by regolith --- the layers of soil, saprolite, and weathered bedrock that together comprise the critical zone. Recent research has focused on understanding fluxes of minerals, water, and energy through the critical zone under steady state assumptions. However, in eroding landscapes, regolith and soil are produced from the bedrock as it is exhumed. Therefore, at some point in time, every location on the Earth's surface currently mantled by regolith experienced an onset of weathering processes. This initial creation of a critical zone from rock is poorly understood. Here we study initial critical zone formation from exposed bedrock by combining surface and subsurface geophysical observations at a site where regolith appears to be forming from bedrock on a granodiorite outcrop in Panola Mountain State Park, Georgia, USA. Vegetation gains an initial foothold on the outcrop by colonizing microtopographic depressions created by differential weathering of contrasting bedrock compositions. We observe a range of colonization stages, from moss to grasses to small bushes and eventually to large trees. Subsurface signatures of the vegetation include enhanced radar reflectance and reduced seismic velocities, with larger vegetation associated with stronger subsurface signals. Using a space-for-time substitution approach, we propose an evolutionary sequence for critical zone development. While disentangling the chicken-and-egg questions that pervade this topic remains challenging, our results suggest that geological heterogeneity can provide the initial catalyst for colonization, but ultimately vegetation itself plays a strong role in producing subsurface structures we associate with the critical zone. Supplementary Material File (1026694_0_merged_1742131800.pdf) Download 2.42 MB File (panola cz development 2025-03-16.docx) Download 33.32 MB File (panola cz supplement 2025-03-16.docx) Download 8.09 MB Information & Authors Information Version history V1 Version 1 07 April 2025 V2 Version 2 26 February 2026 Copyright This work is licensed under a Creative Commons Attribution 4.0 International License Keywords bedrock critical zone initiation near surface geophysics succession weathering Authors Affiliations Sean P. Bemis 0000-0001-7854-6394 [email protected] Virginia Tech View all articles by this author W. Steven Holbrook 0000-0003-0065-8841 Virginia Tech View all articles by this author Brady A Flinchum 0000-0003-0395-0450 Clemson University View all articles by this author Jorden L Hayes 0000-0001-5967-3953 Dickinson College View all articles by this author Russell P Callahan 0000-0002-0091-3446 University of Connecticut View all articles by this author Ciaran J Harman 0000-0002-3185-002X Johns Hopkins University View all articles by this author Bradley J. Carr 0000-0002-1378-4911 University of Wyoming View all articles by this author Clifford S. Riebe 0000-0002-8744-8208 University of Wyoming View all articles by this author Funding Information National Science Foundation 2012353 W. Steven Holbrook Metrics & Citations Metrics Article Usage 371 views 301 downloads .FvxKWukQNSOunydq8rnd { width: 100px; } Citations Download citation Sean P. Bemis, W. Steven Holbrook, Brady A Flinchum, et al. Creating a Critical Zone: Feedbacks Between Bedrock Geology, Hydrology, and Vegetation on an Exposed Bedrock Surface, Panola Mountain, Georgia, USA. Authorea . 26 February 2026. DOI: https://doi.org/10.22541/au.174405192.22137346/v2 If you have the appropriate software installed, you can download article citation data to the citation manager of your choice. Simply select your manager software from the list below and click Download. For more information or tips please see 'Downloading to a citation manager' in the Help menu . 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