【作者】 陈国俊； 李超； 张功成； 吕成福； 郑胜； 马明；

【Author】 CHEN Guojun;LI Chao;ZHANG Gongcheng;LV Chengfu;ZHENG Sheng;MA Ming;Gansu Province/ Key Laboratory of Petroleum Resources Research,Institute of Geology and Geophysics,Chinese Academy of Sciences;Research Institute of China National Offshore Oil Corporation;University of Chinese Academy of Sciences;

【机构】 甘肃省油气资源研究重点实验室/中国科学院油气资源研究重点实验室； 中海油研究总院； 中国科学院大学；

【摘要】 伴随全球深水油气勘探的进展,深水沉积体系尤其是深水扇和深水水道已成为科学界研究的热点和前沿。中央峡谷是发育于南海西北陆架边缘的一条低曲率"S"形深水水道,本文应用新采集的二维地震数据,分析了中央峡谷所搬运沉积物的物源及最终沉积位置和方式。认为中央峡谷可划分为5期次级水道,而其形成过程可划分为三个时间段:(1)距今10.5 Ma左右,形成中央峡谷的雏形,对应第1期次级水道;(2)距今5.5 Ma左右,第2期次级水道开始发育;(3)距今5.5-4.2 Ma间,第3-5期次级水道依次发育。中央峡谷的物源主要来自乐东深水扇,作为莺歌海盆内沉积物二次搬运进入中央峡谷的中转站,乐东深水扇是中央峡谷的直接物源供给体,其二者是同时发育的同一沉积体系,而非前人认为的同一物源在不同时期形成的两个不同沉积体。另外,在中央峡谷的东(末)端发现一大型深水扇,并依据其发育位置命名为"双峰深水扇",双峰深水扇共发育4期:第1-3期分布在双峰盆地中南部,受盆地古地形向东南方向倾斜的影响,前3期双峰扇自西沙海槽—双峰盆地过渡带持续向东南方向的南海中央海盆推进,发育规模逐渐增大;第4期以朵叶体的形式发育在盆地北部,以中央海山与前3期相隔。双峰深水扇的物源由中央峡谷提供,本文提出乐东深水扇—中央峡谷—双峰深水扇为同一沉积体系的新认识,将其称为"莺琼双峰多阶深水扇体系"。该体系的形成与演化主要受控于南海西北的古海底地形、物源和相对海平面变化。更多还原

【Abstract】 The Central Submarine Canyon is a large unusual deepwater channel-levee system in thenorthwestern shelf-margin of the South China Sea.It is oriented parallel to the continental slope with low curvature of ’S’ shape.The paper has applied new collected 2D seismic data to analyze the provenance,depositional position and pattern of the sediments that transported by Central Submarine Canyon.This paper has shown that the initial Central Submarine Canyon formed at 10.5 Ma,it’s sourced by Red River Fan,and there are the same depositional systems,but not two depositional elements at different time.A large-scale submarine fan system has been discovered at the end of the Central Submarine Canyon,and named it as "Shuangfeng Submarine Fan".Four phase of submarine fan developed and consists of the Shuangfeng Fan.The first phase characterized by small-scale and limited distribution at the transition zone of Xisha Trough-Shuangfeng basin.The second and third phase are characterized by large-scale,there were developed at central and southern part of the basin.The fourth phase developed in the form of lobe and,distributed at the northern part of the basin.The Source of the Shuangfeng Submarine Fan was supplied by Central Submarine Canyon,which are of the same sedimentary system with Red River Fan,the paper name it as "Pan-Central Submarine Canyon System".The evolutionary process of the Ying-Qiong-Shuangfeng multi-rank deepwater fan System is mainly controlled and affected by pale-seafloor topography,source and the relative sea-level.更多还原