A study on late Quaternary turbidites in the northeastern South China Sea

• Main Authors: Shun-Wen Yu, 俞舜文
• Other Authors: 蔡龍珆
• Format: Others
• Language: zh-TW
• Published: 2019
• Online Access: http://ndltd.ncl.edu.tw/handle/gw5h7p

博士 === 國立中央大學 === 應用地質研究所 === 107 === Turbidity currents are the major agents for transporting sediments from the continents into the deep sea. Thickly-bedded turbidites commonly serve as good hydrocarbon reservoirs and are the major target for deep water hydrocarbon exploration. The South China Sea is the largest sink in the world for fluvial sediments (around 1,600 million metric tons) among marginal seas, and the northeastern South China Sea is where the passive continental margin meets Taiwan orogenic wedge and the Manila subduction zone. Therefore, the northeastern South China Sea is an ideal place to compare and contrast the turbidite development in the neighboring rifted continental margin and orogenic wedge. We used 3 giant piston cores (MD3291, MD3266, and MD3264) recovered onboardR/V Marion Dufresne in 2010 along the rifted continental margin and Taiwan orogenic wedge to reconstruct the depositional history late Quaternary turbidites by sedimentologic study and AMS 14C dating. Our results reveal frequent turbidity currents occurred during ~21 kyr to 15 kyr BP and ~10 kyr BP to the present day in the study area. The correlation among turbidite occurrence and changes in eustasy, climate, and rainfall intensity in southern Taiwan reveal that the frequency of turbidity currents is most likely related to sea level and climatic changes, even for the cases that canyon heads and river mouths are separated by a wide shelf.