Abstract
Despite recent intense investigations, the stratigraphy of Late Quaternary Taipei Basin deposits remains fraught with uncertainties and controversies. To improve our understanding of Taipei Basin stratigraphy, a sequence stratigraphic analysis was carried out in 4 deep boreholes recently recovered from the western part of the Basin. For each borehole, the facies successions were established according to an alluvial-lacustrine-estuarine depositional model, and the resultant facies stacking patterns used to delineate the key stratigraphic surfaces, including sequence boundaries, transgressive surfaces, and flooding surfaces. These key surfaces can be correlated among boreholes and used to divide Taipei Basin deposits into 3 sequences and a series of systems tracts. In spite of minor contradictions that remain to be investigated, the proposed sequence stratigraphy is generally consistent with the extant palynostratigraphy and lithostratigraphy. Nevertheless the 14 key surfaces of sequence stratigraphy significantly improve the stratigraphic resolution offered by the 7 zonal boundaries and 4 formational boundaries of palynostratigraphy and lithostratigraphy. In addition, the age of each key surface can be inferred by correlating with the Late Quaternary oxygen isotopic curve and used to constrain the depositional history of each borehole. The agreement between the facies variations and the glaciation-modulated sea level change also demonstrates that Taipei Basin sedimentation was manipulated mainly by eustacy.