| dc.description.abstract | The continental slope is located between the continental shelf and the deep-sea basin, and is the pathway to transport terrestrial sediments to the deep sea. However, the water depth of the upper continental slope ranges from tens of meters to hundreds of meters, and the sediments are susceptible to periodic changes affecting by sea level change during the sediment transportation process. The southeast Gaoping slope, southwestern offshore Taiwan is adjacent to the Gaoping Canyon, the upper area is connected to the Gaoping shelf, and the bottom is headed to the Manila Trench. Previous studies have shown that there is a strong bottom current up to 1 m/s current speed northeast Xiaoliuchiu islet, causing seabed erosion on the eastern slope of the canyon. The dynamic behavior of the sediments transported by this erosion, the sliding process of the gravity driven sediments in the Gaoping continental slope area, the relationship between the sea level changes, and the influence of the surrounding ocean currents have not been discussed. In this study, we applied high resolution marine sparker seismic method to acquire nine seismic profiles across southeast Gaoping slope, constructing seismic sequence stratigraphy framework since 150 ka.
The results show that the study area can be identified seismic sequence systems over the past 150 ka, including the 135 ka MIS 6 glacial erosion event, the last glacial maximum (LGM, Last Glacial Maximum) erosion event, and seismic sequences Lowstand System Tract (LST), Transgressive System Tract (TST), and Highstand System Tract (HST) sequence since LGM period. The mud diapir uplift adjacent to Xiaoliuchiu islet developed serious resent submarine slope failures, and Xiaoliuchiu channel erosion can be extended east toward middle southeast Gaoping shlef. In addition, the sediment movement of the southeast Gaoping slope can be divided into two categories. First is gravity driven sediment wave along the slope. The sediment wave can be observed since -100 meters, and it can be extended to the middle slope. Second is mud diapir and mud volcano activities in the lower slope caused large scale submarine landslide which failure sediments accumulate at the bottom of the slope. It is worth noting that the sediment wave in the study area sliding along a interface between LST sequence and HST sequence indicating high pore fluid pressure of terrestrial sediments within LST may play a key role to surface sediment gliding. | en_US |