Exploring the Distribution and Occurrence of Cenozoic Volcanic Geoheritages in the Khorat Plateau, Thailand

The Cenozoic basalts of the Khorat Plateau are prevalent in Thailand’s lower northeastern region. Despite their abundance, detailed studies on the composition and morphology of these basalts are scarce. This research examines the relationship between volcanic morphology and geochemistry in northeastern Thailand, focussing on basalts from Buriram, Surin and Sisaket Provinces. Using polarised microscopes and X-ray fluorescence (XRF) analysis, this study investigates the petrography and geochemistry of these basalts. Field observations reveal eruptions from both shield volcanoes and fissures, with notable shield volcanoes including Khao Phanom Sawai, Khao Phra Angkhan, Khao Phanom Rung, Khao Kradong, Khao Plai Bat and Phu Fai. Petrographic analysis identifies these basalts as olivine basalt with porphyritic textures and occasional trachytic textures. Geochemical classification includes trachybasalt, basalt, basaltic andesite, basaltic trachyandesite and andesite, with SiO₂ contents ranging from 51.07% to 61.46%. Trace element analysis categorises them as alkaline basalt. Although shield volcanoes show higher SiO₂ concentrations compared to lava flows, morphological differences do not consistently align with SiO₂ trends, suggesting that magma viscosity and eruption patterns are influenced by additional geochemical factors. This study also highlights the importance of engaging local communities to enhance understanding of volcanism’s historical and cultural impacts.