THE CENOZOIC LEAF FOSSIL AND PALEOCLIMATE AT DOI TON, MAE SOT DISTRICT, TAK PROVINCE, THAILAND

Abstract

Abundant leaf fossils are preserved as imprinted in sandstone layers at Doi Ton temple, Mae Sot Basin, Tak Province. They were found alongside with branches, tree barks, fossil bivalves, and gastropods. The leaf fossils preservation is rare in the Cenozoic deposit in Thailand; thus, the study site provides a great opportunity for research to solve the paleo-depositional environment and paleoclimate of the region. From primary investigations of leaf morphology, sedimentology, and stratigraphy, Doi Ton deposits were classified into three parts. The lower part is composed of the whitish gray fine-grained sandstone, the middle part is reddish brown to yellowish brown conglomerate and fine-grained sandstone and the upper part is the reddish siltstone. The leaf fossils are abundant in fine-grained sandstone and some plant fragments are also present at the base of the conglomerate. The middle and upper Doi Ton successions show a sign of channel deposits. Bottom sedimentary structures indicated paleocurrent to the northwest direction. The leaf fossils can be classified into 23 morphotypes of dicot leaves with an unlobed and untoothed margin and two of gymnosperm leaves. These dicotyledonous leaves suggest warm and humid paleoclimate.