| Summary: | 碩士 === 國立成功大學 === 地球科學系 === 103 === This study attempts to interpret the sedimentary environments of the Kueichulin Formation to Chinshui Shale of the Yunghoshan, Chinshui, Fengfu and Paishatun areas in Miaoli, NW Taiwan. Sequence stratigraphy of the studied strata was analyzed based on the model of stacking pattern of parasequence units and system tracts. Third-order sea level curves were reconstructed according to variation in thickness of the defined parasequence units and were compared with the global sea level curve.
Sedimentary environments of the strata were interpreted based on well-logs and cuttings data. Eight depositional facies were identified and grouped into two depositional systems, including open shallow marine systems and barrier and lagoon systems. The Kuantaoshan and Yutengping sandtones can be divided into 16 and 14 parasequence units, respectively. The reconstructed third-order sea level changes for deposition of the formations are both characterized by two cycles of “fall and rise”, which are consistent with vertical variation in interpreted sedimentary environments of the formation deposition. Comparing with the global sea level curves, the age of Kueichulin Formation deposition can be determined as during 6.5-3.4 Ma. Vertical variation in sedimentary environments of the lower Chinshui Shale is incompatible to the coeval global sea level change, indicating that continental margin has evolved to foreland basin since this period.
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