[H-CG23] 堆積・侵食・地形発達プロセスから読み取る地球表層環境変動

[HCG23-P01] A foreland basin with two distinct modern sediment dispersal systems: An example from Taiwan

*Cheng-Shing Chiang¹、KanHsi Hsiung³、Ho-Shing Yu² (1.National Museum of Natural Science、2.National Taiwan University 、3.Japan Agency for Marine-Earth Science and Technology)

キーワード：orogenic sediment, sediment conduit, sediment transport, marginal sea basin

The western Taiwan Foreland basin(WTFB) is a classical peripheral foreland basin longitudinally bounded by the East China Sea to the north and the South China Sea to the south and laterally over-spills orogenic sediments to the nearby marginal sea basins. Due to oblique diachronous collision the WTFB has evolved into two subbasins: a mature basin in central-north Taiwan and an immature one in southern Taiwan, accompanied by two distinct sediment routing systems. In the north, the Choushui River drainage, narrow seaway of the Taiwan Strait shelf, Huapingshu Channel, Mienhua Canyon and the southern Okinawa Trough are integrated into a united sediment dispersal system, allowing sediments sourced by the mature basin to be laterally over-spilled to the East China Sea and finally deposited at SOT. In southern Taiwan, the Kaoping River drainage, Kaoping submarine canyon, deep-sea Penghu Channel and northern Manila Trench(NMT) are inter-connected to form a linear sediment conduit, allowing sediments mainly derived from the immature basin longitudinally transported to the South China Sea basin and over-spilled into NMT.