Seismic Structures and Stratigraphy Analysis in Offshore Area between Taichung and Changhwa

Reporter: Yang-Chen Chen

Abstract

West Taiwan basins have evolved from a Palaeogene rift setting through a post-breakup setting into a latest Miocene-Recent foreland basin. Seismic-stratigraphic studies indicate Cenozoic strata to be divided into four major seismic sequences. The four stage tectonic cycle of pre-rift, syn-rift, post-breakup and foreland basin has controlled the sedimentation of the Cenozoic sediments. This study integrated reflection seismic and well-log data to reveal the underground structure and stratigraphy in offshore area between Taichung and Changhwa since the Eocene. Seismic data show that all the stratigraphic units deepen toward the east and the north due to orogenic loading. In E-W profiles exist a distinct unconformity (or strong reflection surface) and an N-S fracture in the eastern part of the study area. Below this unconformity (or strong reflection surface), there are normal faults dip in high angles and form grabens and horsts. This N-S fracture seems to break irregularly and it could be a fault.

References

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