Sedimentary characteristics and paleoenvironmental evolution of the northwest coast of the Taiwan Shoal since Late Pleistocene

ZK2, a shallow drilling core taken from the northwest Taiwan Shoal off the coast of the Dongshan Island, Fujian Province, is studied for establishing the stratigraphic sequence and paleoenvironmental evolution of the shoal. According to the data of AMS¹⁴C dating, grain size, micro-paleontology and detrital and clay minerals, two marine strata and two terrestrial strata are recognized. The top marine stratum is a mixture of modern sediments and the late Pleistocene relict deposits formed by tidal current since the Holocene high sea level, and the bottom terrestrial layer is a fluvial deposit formed during the MIS4 when the sea level was low. The fine-grained strata in the middle can be further divided into two layers. The lower layer is formed in MIS3 in a frequently changing environment from lagoon, to tidal flat or salt marsh, while the upper layer is the filling deposits in incised valleys formed during the period from MIS3 to the peak of LGM. The southern Taiwan Strait had experienced obvious tectonic subsidence during MIS3, but emerged above the sea level in LGM and left a hiatus or discontinuity behind. This paper provides some new evidence for further research of sedimentology, stratigraphy and paleoenvironmental evolution of the region from the northwestern margin of the Taiwan Shoal to the southeast coastal area of the Fujian Province.