Problems of Neogene biostratigraphic correlation in Thailand and surrounding areas

  • Benjavun Ratanasthien Department of Geological Sciences, Faculty of Science, Chiang Mai University, Chiang Mai, Thailand.
Keywords: Neogene, biostratigraphy, vertebrate fossils, palynology, paleoclimate.


Neogene stratigraphic correlation in Thailand was based on lithology until exploration for fossil fuel deposits in 1918 led to the discovery of vertebrate fossils at Mae Moh coalfield. This area became the key to biostratigraphic correlation in Thailand. The main tools in Neogene correlation are vertebrate fossils (including those of small mammals) and palynology. Lithological correlation is now used only as a tool in comparing tectonic events, especially during Neogene, where repeated rifting has occurred throughout Southeast Asia.

Though biostratigraphy has become the preferred tool in stratigraphic correlation, there are still areas of disagreement on correlations for many parts of Thailand. In the north, vertebrate fossils, mammals, and palynological floras seem to agree very well (or differ within a close range). In the south, recent work on small mammal fossils does not correlate well and contradicts results from palynology and microinvertebrate fossils. The disagreements stem from the use of different methods, although there are also problems arising from trying to correlate sparse paleoclimatic evidence. For advances to occur in the 21st Century, a well-funded, cooperative correlation program acquiring data from multidisciplinary studies is required.