摘要
综合分析了地质、地球物理、地球化学、古生物学等多方面资料,将南海海域控制新生代主要沉积盆地的基底划分为6个区:北部湾古生界断堑基底区、莺歌海古生界走滑拉分基底区、琼东古生界断陷基底区、西沙北古生界裂谷基底区、西沙南古生界走滑伸展基底区和南沙古-中生界伸展基底区。通过区域地质分析,初步重建了该海域的大地构造演化历史。该海域新生代沉积基底在前新生代时期与其北面陆上云开地区同处于特提斯构造域中,形成于古特提斯构造域背景之中,为东特提斯多岛洋体系的重要组成部分。古特提斯的东延段在研究区有3个分支,即云开北、琼北、琼南3个海盆,分别表现为现存的云开北、琼北、琼南等缝合断裂带,使该区新生代沉积基底表现出明显的分区性。自晚古生代以来,伴随古、中特提斯的成生、消亡,该区新生代沉积基底经历了5个阶段的演化,其动力机制是一个复杂的研究课题,拆沉-去根-释压熔融是其主要动力机制,造成了特提斯构造演化上的序列性和叠置性。
Based on the synthetical analyses of geology, geophysics, geochemistry, paleontology and paleomagnetism, the basements which controlled the major Cenozoic sedimentary basins in the South China Sea have been divided into six districts: Beibu Gulf Paleozoic faulted basement, Yinggehai Paleozoic strike-slip pull-apart basement, Qiongdong Paleozoic rift-faulted basement, northern Xisha Paleozoic rifted basement, southern Xisha Paleozoic extension basement, and Nansha Paleozoic-Mesozoic extension basement. The evolution history of the basements is divided into five stages: ①D-D-P_(1),the stage of development of eastern Tethyan archipelago ocean; ②P_(2),the stage in which Meso-Tethys (Paleo-South China Sea) began to open and the Paleo-Tethys to subduct; ③T-K_(1),the stage in which the eastern Paleo-Tethyan blocks sutured; ④K_(2)-N_1~1,the stage of the formation of modern South China Sea and the consumption of the Paleo-Tethys; ⑤ since N_1~2,the South China Sea stopped spreading and the Australian plate subducted and compressed. The tectonic evolution of the Tethys in the area shows the characteristics of a series of evolution of Paleo-Tethys-Meso-Tethys-Ceno-Tethys and regenerative inherit superimposition in time and space, just similar to Yunnan-Malay Paleo-Tethys regenerated on the basement of Deqin Proto-Tethys and Indian River-Yarlung Zangbo River Ceno-Tethys regenerated on the basement of South Paleo-Tethys(represented by India River-Yarlung Zangbo suture). The delamination- de-rooting- decompression- melting is the main formation dynamic mechanism of Tethys.
出处
《海洋地质与第四纪地质》
CAS
CSCD
北大核心
2004年第1期15-28,共14页
Marine Geology & Quaternary Geology
基金
中国科学院知识创新项目(KZCX2 SW 117
KZCX2 10 2和KZCX2 2 0 9)
国家重点基础研究发展规划 (G2 0 0 0 0 46 70 2 )
国家"十五"社会公益研究计划 (2 0 0 1DIA50 0 41 0 1 )
中国科学院王宽诚博士后工作奖励基金
边缘海地质与古环境开放实验室基金(BYH0 2AA0 1 )联合资助
关键词
特提斯
演化动力机制
沉积基底
新生代
南海
evolution dynamic mechanics of Tethys
Cenozoic sedimentary basements
the South China Sea
