| Summary: | 碩士 === 國立中央大學 === 應用地質研究所 === 94 === The continuous coring of the TCDP-A (Taiwan Chelungpu-Fault Drilling Project-A, 2003 m in drill depth) borehole recovered a Pliocene-Pleistocene Taiwan foreland sequence in central Taiwan. The drilled interval records the shallow marine sedimentation of an evolving foreland basin from its inception (i.e., the Kueichulin Formation, 1300m-1710m) through the under-filled stage (i.e., the Chinshui Shale, 1013m-1300m) into the mature/over-filled stage (i.e., the Cholan Formation, 0m-1013m, 1710m-2003m).
The continuous cores provide us a unique opportunity to decipher the sedimentology and lithology of an evolving marine foreland basin through an integrated study of core lithofacies and geophysical wireline logs. Fifteen lithofacies and 12 trace-fossil assemblages were recognized from the TCDP-A cores on the basis of the lithology, grain size, sedimentary structure, degree of bioturbation, trace fossils, and fossils content. Genetically related lithofacies were then combined into 8 facies associations. These facies associations are deposits accumulated in environments of outer offshore, inner offshore, lower shoreface, upper shoreface, barrier complex, tidal flat, lagoon, and swamp, respectively. The vertical change of paleo-environments documents the Taiwan foreland basin evolving from an early overall transgressive phase(i.e., the Kueichulin Formation and Chinshui Shale) into a late regressive phase(i.e., the Cholan Formation).
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