--> Abstract: Seismic Stratigraphic Sequences and Deformation Events in the Southern East China Sea Basin, by F. Kong, L. A. Lawyer, and T-Y. Lee; #90937 (1998).
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Abstract: Seismic Stratigraphic Sequences and Deformation Events in the Southern East China Sea Basin

KONG, FANCHEN, University of Texas at Austin, LAWRENCE A. Previous HitLAWYERNext Hit, University of Texas at Austin, TUNG-YI Previous HitLEETop, National Taiwan Normal University

Summary

Basin evolutionary processes based on depositional and stratigraphic characteristics of the southern East China Sea Basin, offshore northern Taiwan, are presented here as preliminary results. Unlike previous studies which focused primarily on stratigraphy or structures, our basin evolution model is an integration of deposition, deformation events, and their relations with interactions of major plates along the eastern Asian margin. Data for our model are taken from multi-channel seismic reflection sections, free-air gravity anomalies, and other geological and geophysical data. Standard methods are used in our interpretation of seismic sections, but seismic sequences and structures are addressed simultaneously in this work. In order to obtain a complete profile of basin evolution history and to extract stratigraphic deformation events, not only synrift sequences, which are the major targets of previous studies, but also postrift sequences as well as a sequence from the upper part of the basement are studied in detail. Seismic sequence boundaries are defined by correlating and extrapolating unconformities with well controls and are taken as regional unconformities. Seismic sequences. In our study area, seven regional unconformities and a few local ones, divide basin stratigraphy into ten to eleven sequences with at least three progradation-retrogradation cycles, Several new sequences and some large canyon cuttings are also recognized. Stratigraphic deformation analysis indicates that basin stratigraphy has been strongly deformed with multiple stages of extension and contraction with different mechanisms and origins. Our deformation analysis focuses on a late Cretaceous-Early Paleocene large-magnitude continental extension, a Middle Oligocene basin inversion, the offset nature of the southern Taiwan-Sinzi Belt, and the timing and mechanism of the opening of the southern Okinawa Trough. Contrary to previous suggestions that the East China Sea Basin developed from an extension caused solely by eastward extrusion of the Asian blocks due to the Indian-Eurasian collision or as a continental rift, it is concluded that the evolution of the East China Sea Basin has been fundamentally controlled by interactions of major plates along the western Pacific margin since Jurassic-Cretaceous.

AAPG Search and Discovery Article #90937©1998 AAPG Annual Convention and Exhibition, Salt Lake City, Utah