SOURCE ROCK QUALITY, OIL COMPOSITION AND THERMAL MATURITY OF CENOZOIC RIFT-LAKE BASINS, ONSHORE THAILAND

摘要

Central and northern Thailand contains numerous Cenozoic rift basins (e.g. Polachan et al., 1991). The Phitsanulok Basin is the largest (～ 6000 km2), and the basin has a half-graben configuration with a sediment-fill reaching a thickness of about 8 km. In northern Thailand the basins range in size from ～ 30-1400 km2, and generally the basin fill in both the central and northern basins is only from 1-4 km thick. Syn-rift deposition of lacustrine oil shales and coals occurred during Oligocene to Early Miocene extension tectonism, and in several of the basins the oil shales and coals were later exhumed (e.g. Gibling, 1985; Curiale and Gibling, 1994; Petersen et al., in press). Despite the generally shallow burial depth of the oil shales and coals, the oil shales act as source rocks in the Suphan Buri, Phitsanulok and Fang basins in which waxy oils are produced (Fig. 1).