The initial development of the central Taiwan foreland basin constrained from stratigraphic records

Shao-Ping Chiang

Abstract

The Kueichulin formation deposited during the late Miocene and early Pliocene, it is the oldest part of the Taiwan foreland sequence and subdivided into 3 members, Kuantaoshan sandstone, Shiliufeng shale and Yutenping sandstone, which provide the stratigraphic records of the transition from passive margin into foreland basin in central Taiwan.

By analyzing 3 outcrops and 24 wells loggings, we bring up a depositional system model and the evolution of the basin. Genetically related lithofacies were then combined in to 19 facies associations according to the field works, these facies associations are deposits accumulated in environments of 4 major depositional systems, tide-dominated estuary depositional system, wave and storm influenced shallow marine depositional system, barrier island complex and lagoon depositional system and tide-dominated depositional system.

The isopach, derived from 24 wells loggings and 3 outcrops in central Taiwan, shows a obviously change of the depocenter of the three members of the Kueichulin formation. During late Miocene, the depocenter when the Kuantaoshan Ss. deposited was the same with the stage of the passive margin. In the early Pliocene, the depocenter of the Yutenping Ss further migrate southward, where the Peikang-High started receive sediments and subsided rapidly.

We try to make sure the relationship between the paleoenvironment changes and the global sea level changes , however, we can’t find a good connection between them, and we think the mismatch of the two happenings were due to the effect of the tectonic subsidence of the foreland basement resulted from the overriding of the Luzon arc onto the passive margin.

Reference

江紹平（2007）早期中部台灣前陸盆地桂竹林層的地層紀錄。國立中央大學地球物理研究所碩士論文。

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