Abstract: Lower Miocene Sequence Stratigraphy of Taishi Basin, Offshore Western Taiwan

Jhy-Shing Ting, Tung-Yi Lee

By applying sequence stratigraphic concepts to the lower Miocene sedimentary sections in Taishi Basin, offshore western Taiwan, it is possible to identify four third-order sequences from subsurface information. The overall depositional environment of these sequences is in a deltaic setting. Following the early Aquitanian flood (24.8 Ma), the basin experienced a long period of sea level highstand, which generated more than 400 m of highstand prograding units. In late Aquitanian time, a thick retrogradational package (~250 m) was developed in response to rising sea level. Sandy units are now the dominant sediment type in the Taishi Basin. Until the early middle Miocene (15-16 Ma), the basin was flooded and deposited with thick marine shale.

This analysis shows that the lower Miocene sedimentary sequences in the Taishi Basin have a good correlation with the Haq et al. (1987) chart, which would imply a passive margin setting for the Taishi Basin in the early Miocene. The predictive nature of the sequence stratigraphic technique can help in redefining the hydrocarbon play concepts in this area.

AAPG Search and Discovery Article #90982©1994 AAPG International Conference and Exhibition, Kuala Lumpur, Malaysia, August 21-24, 1994