Geochemical analysis of chert for interpretation of depositional environment in the Saraburi region, Thailand

摘要

The Saraburi Group in the Saraburi-Pak Chong area can be sub-divided into 8 lithofacies representing shelf or platform, basin margin and deep basin environments.Lithofacies of shallow marine environments include thin-to-thick bedded limestone and dolomite, boundstone and dolomite, and sandstone, shale and limestone.Basin margin and deep basin environments are represented by crinoidal limestone, micritic limestone, limestone conglomerate, allodapic limestone, shale and cherts (Chonglakmani, 2001, 2005).We used major, trace and rare earth elements data to investigate the depositional environment of a chert sequence in the Muak Lek district, Saraburi Province, Thailand The studied section belongs to the Saraburi Group and comprises shale, thin-bedded cherts and limestone of deep marine facies.The cherts are brown to dark grey and yield moderate and poorly preserved radiolarians.The radiolarian fauna shows that the cherts accumulated in the Middle Permian to early Late Permian.