南海西北与西南次海盆沉积通量及其控制因素

作为西太平洋陆源沉积"源-汇"过程的重要场所,南海海盆半封闭的构造环境使得其与开放大洋的物质交换十分有限,沉积物保存基本完整,可以建立起南海沉积过程与区域重大构造事件、气候变化、海平面变化等之间的系统联系.选取南海西南与西北两个次海盆为对比研究区,基于穿越海盆的高分辨率多道地震测线和国际大洋发现计划(Internati...

Sedimentary Budget and Controlling Factors of the Northwest and Southwest Sub-Basins,the South China Sea

South China Sea (SCS) is not only the crucial pathway for transporting terrigenous materials from Eurasia to the western Pacific Ocean since the Early Oligocene, but also the dominant accumulation and preservation place as a result of limited material exchange between the semi-closed oceanic basin and the open ocean since the Middle Miocene. Calculation of the sedimentary budget in different geological times is an important part in quantifying the sedimentary process in the SCS, which will not only construct the relationship between the sedimentary process of the SCS and the regional tectonic events, climate change, eustatic sea level change, etc, but also to improve our understanding on the "source-to-link" process of the West Pacific region. Based on multichannel seismic profiles across the northwest sub-basin (NWSB) and the southwest sub-basin (SWSB), combined with drilling results from IODP Expeditions, the sedimentary budget of the NWSB and SWSB has been calculated, and the controlling factors in different geological times have been discussed to reconstruct the Cenozoic sedimentary history. Efforts have been also made on the sedimentary provenance analysis. The sedimentary budget of the NWSB and the SWSB showed distinct characteristics in different geological times. Sedimentation is generally dominated by regional tectonic events (such as the uplift of the Tibet Plateau), monsoon, continental fluvial systems and sea-level changes, but will be complicated by local tectonic events and geographic position. The main sediment source of the NWSB was the terrestrial sediment transported from the South China, and a small amount from Red River, the Hainan Island, and Dongsha local uplifts. The sediment provenance of the SWSB was mainly from the Indo-China Peninsula, the Nansha area, and the Palawan before the Late Miocene. After that, sediments were mainly transported from the modern Mekong River.