珠江口盆地−琼东南盆地深水区新生代构造沉积演化对比分析  

Comparative study on the Cenozoic tectonic and sedimentary evolution in the deep water areas of the Zhujiang River Estuary Basin and the Qiongdongnan Basin

作　　者：谢辉 周蒂[2] 石红才[1] 李元平[3] 孔德明 Xie Hui;Zhou Di;Shi Hongcai;Li Yuanping;Kong Deming(Guangdong Key Laboratory of Coastal Ocean Variation and Disaster Prediction,Guangdong Ocean University,Zhanjiang 524088,China;Key Laboratory of Ocean and Marginal Sea Geology,Chinese Academy of Sicences,Guangzhou 510301,China;CNOOC China Limited,Shenzhen Branch,Shenzhen 518054,China)

机构地区：[1]广东海洋大学广东省近海海洋环境变化与灾害预警重点实验室,广东湛江524088 [2]中国科学院边缘海与大洋地质重点实验室,广东广州510301 [3]中海石油(中国)有限公司深圳分公司,广东深圳518054

出　　处：《海洋学报》2021年第3期48-61,共14页

基　　金：国家自然科学基金(41606065,41704085);广东省自然科学基金(2016A030310331);中国科学院边缘海地质重点实验室开放基金(MSGL15-02);广东海洋大学博士启动基金项目;广东海洋大学海洋科学科研团队项目(002026002004)。

摘　　要：南海北部陆缘记录了南海形成演化的历史,但是其新生代构造沉积演化特征在东段和西段的差异及其原因目前还不太清楚。本文分别在珠江口盆地和琼东南盆地的深水区选择了数口构造地理位置相似的井通过精细地层回剥分析,重建了两沉积盆地的沉积速率和沉降速率并结合前人研究成果进行了对比分析。研究结果发现,两沉积盆地在裂陷期的沉积和沉降特征基本相似,但是两者在裂后期的构造沉积演化特征差异明显。珠江口盆地深水区沉积和沉降速率都表现为幕式变化特征,其中沉积速率表现为“两快三慢”的特征而沉降速率表现为“两快一慢”的特征。琼东南盆地深水区的沉积速率表现为“地堑式”变化特征,但是沉降速率表现为“台阶式”上升的变化特征。琼东南盆地“台阶式”上升的沉降速率推测主要是受到海南地幔柱伴随红河断裂的右旋走滑而向西北漂移的影响,这也与南海西北部的岩浆活动以及周围盆地的沉降特征吻合。红河断裂在2.1 Ma BP的右旋走滑控制了琼东南盆地1.8 Ma BP以来的快速沉积和加速沉降分布。The formation and evolution of the South China Sea is well recorded in the northern continental margin.But the discrepancies of the tectonic and sedimentary evolution between the west and east of the northern margin are still enigmatic.Several drilling and simulation wells with analogous geological setting are chosen from the deep water areas of the Zhujiang River Estuary Basin and the Qiongdongnan Basin.Based on backstripping and previous studies,high resolution sedimentation rates and subsidence rates are constructed.Results show that both two basins are characterized by analogous sedimentation rates and subsidence rates in the syn-rift stage,but significant discrepancies are revealed in the post-rift stage.Episodic sedimentary and tectonic evolution characteristics are revealed in the Zhujiang River Estuary Basin,sedimentation rates are characterized by“two rapid sedimentation periods and three slow sedimentation periods”and subsidence rates are characterized by“two rapid subsidence periods and one slow subsidence period”.But the sedimentation rates are characterized by“graben”style evolution,and the subsidence rates are characterized by“step-up”style evolution in the Qiongdongnan Basin.The“step-up”subsidence rates in the Qiongdongnan Basin might be controlled by activities of the Hainan mantle plume which moved northwestward derived from the dextral strike-slip of the Red River Fault.And it coincided with the magmatism and the subsidence rate in the northwest margin of the South China Sea.The distribution of the rapid deposition and accelerated subsidence in the Qiongdongnan Basin after 1.8 Ma BP could be mainly controlled by the meanwhile dextral strike-slip of the Red River Fault.

关 键 词：珠江口盆地 琼东南盆地 深水区 构造演化 沉积演化 对比分析 

分 类 号：P736[天文地球—海洋地质]