A multidisciplinary approach to the geology of Carboniferous depositional environments in the Khorat Plateau, Thailand

This study investigates the Carboniferous sedimentary rocks of the western Khorat Plateau, a key region within the Indochina terrane characterized by complex tectonic evolution. Despite its geological importance, detailed analyses of depositional environments and chronology remain limited. To address this gap, lithological, geochemical, petrographic, and palaeontological methods were applied to data from eight boreholes and a quarry outcrop. The findings reveal northwest-dipping limestone interbedded with black shale and siltstone, with carbonate petrographic analyses indicating textures ranging from mudstone to grainstone, formed in both low-energy (lagoon or below wave-base) and high-energy (platform margin) environments. Clastic rocks, including shale, Fe-shale, wacke, and litharenite, are interpreted as volcanic arc-related, based on geochemical signatures. The presence of the Carboniferous (Mississippian) foraminifera Endothyra provides robust age constraints. These results offer significant insights into the tectonic history of Southeast Asia, particularly regarding paleoenvironments and biodiversity during the Paleozoic Era.