Mid Tertiary palynostratigraphy of Thailand

Abstract

Mid Tertiary palynological assemblages from fourteen stratigraphic sequences in nine basins in Thailand have been investigated. Special emphasis has been given to the spore-pollen record and its stratigraphic distribution. The basis for defining the zonations is the first or last appearance of key species including: Inaperturopollenites dubius, Alnipollenites verus and Echiperiporites cf. E. estelae. For the first time, correlation between terrestrial and dated marine sequences is achieved. Two palynological zones (SIAM-1 and SIAM-2) have been constructed. SIAM-I Zone is characterized by, inter alia, assemblages comprising high frequencies of gymnospermous pollen, and is provisionally correlated with the planktonic foraminiferal N3–N4 zones of the Trang-1 Borehole, Andaman Sea, indicating an Upper Oligocene to early Lower Miocene age. SIAM-2 Zone is characterized by influxes of tropical taxa and decreasing proportions of the temperate taxa and is provisionally correlated with planktonic foraminiferal N5–N8 zones of the Mergui-1 Borehole, Andaman Sea, indicating a middle to later Lower Miocene age. The results show that the Nong Ya Plong Basin coal seam (pre SIAM-1) is older than the Li Basin coal seams (SIAM-1), Fang Basin oil-bearing intervals (SIAM-2) and Mae Moh Basin coal seams (post SIAM-2). © 1990, Pergamon Press plc. All rights reserved.