|Title:||SUBMARINE PHYSIOGRAPHIC FEATURES IN TAIWAN REGION AND THEIR GEOLOGICAL SIGNIFICANCE||Authors:||GWO-SHYH SONG||Keywords:||Physiography; Sedimentation; Submarine; Taiwan; Tectonics||Issue Date:||2000||Journal Volume:||43||Journal Issue:||2||Start page/Pages:||267-286||Source:||Journal of the Geological Society of China||Abstract:||
The sea floor topography around Taiwan is characterized by its asymmetry of having relatively shallow and flat shelves to the west and markedly deep basins and trenches and high-relief troughs and ridges to the south and east. Tectonics and sedimentation are important factors in forming the submarine topography around Taiwan. Three Pliocene-Quarternary shelves are distributed north and west of Taiwan: East China Sea Shelf (passive margin shelf), the Taiwan Strait Shelf (foreland shelf) and Kaoping Shelf (island shelf) from north to south along the strike of Taiwan orogen. East-west trending ridges of the Yaeyama accretionary wedge and submarine Ryukyu Arc, four offset forearc basins, deep Hualian Canyon-Ryukyu Trench and active backarc basin of southern Okinawa Trough are the major submarine morphologic features in the area off northeastern Taiwan. Off eastern Taiwan, the deep Huatung Basin between the submarine northern Luzon Arc and Gagua Ridge is characterized by relatively flat floor, although several large submarine canyons eroding the basin floor across the basin. Turbidites derived from Taiwan orogen via the submarine canyons are deposited on the basin floor. Off southwestern Taiwan, the broad Kaoping Slope is the major submarine topographic feature. The boundary separating this slope from the South China Sea Slope is the Penghu Canyon. The lower reach of the Penghu Canyon merges gradually into the Manila Trench south of 21°30'N. Off southeastern Taiwan, the forearc region of the Luzon Arc has been deformed into N-S trending ridges and troughs during initial arc-continent collision. The Hengchun Ridge is the most prominent physiographic feature and is the seaward continuation of the Hengchun peninsula. Marine geology in Taiwan region generally reflects a transition from a passive margin to an active margin during the last five million years. Before the collision with the Luzon Arc, the Chinese continental margin in Taiwan has been in a bathymetric setting with shelf, slope, basin and trench with increasing depth in a NE-SW regional trend. After collision with the Luzon Arc and rising of the mountain belt of Taiwan, the continental margin became an active one characterized by a paired thrust-belt and foreland basin, bounded by two remnant marginal ocean basins and transitional subduction-collision systems.
|Appears in Collections:||海洋研究所|
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