地质科技情报2018，Vol.37Issue(4)：51-60,10.DOI:10.19509/j.cnki.dzkq.2018.0406
洋陆转换带类型特征和形成机理及其在南海北部的表现特征
Forming Mechanism and Types Characteristics of Ocean-Continent Transition and Its Performance in Northern South China Sea
摘要
Abstract
Since the 1990 s, ocean-continent transitions (OCTs) , located between passive continent margins and ocean basins, have become international academic research spots for overlying deep-ultra deep water basins which are potential for industrial oil and gas accumulation and OCTs themselves contain abundant information of lithospheric stretching and fracturing.OCTs, formed under the background of passive continent margin stretching and ocean basin expanding, have special characteristics of strongly thinning continent crust, existence of serpentinite and serpentinited peridoite, lack of mafic magma, obvious variance of seismic velocity structure and higher ground surface-heat flow value with the width ranging from 30 km to170 km.According to frequent magmatic activities and double structure of " Moho surface", OCTs can be classified into two types with four phases, namely, A, B1, B2 and B3.Based on the tectonic evolution of OCTs, the crustal stretching process of lithosphere at passive continental margins can be divided into three stages, pure shear stage (dispersion-type evenly extending) , simple shear stage (centralized crust thinning;mantle being exposed) , and pure shear (volcanic influence-lithosphere utmost breaking) .During the formation of OCTs, varying tectonic deformations had important impact on overlying deep-ultra deep water basins.A systematic investigation of the historical and current research of OCTs indicates that the present studies of OCTs in northern South China Sea mainly focus on the various geophysical chracteristics and theres is still inadequate indentification of the geological attribute and boundeary.This study first introduces the analysis of Heshan Sag and Shuangfeng Basin and finds detachment faults grow with weak volcanism in the northern South China Sea.There, OCTs, a non-typical non-magmatic B3 type, stands between 60 km and 170 km in width, declining from the east to the west, including 53.91 km OCTs of Heshan-Shuangfeng tectonic evolution of Heshan Sag is deeply controlled by the OCTs mechanism.The analysis of the forming and characteristics of OCTs by tectono-sequence stratigraphy methods is useful for understanding tectonic evolution and the mechanism of deep-ultra deep water basins in northern South China Sea passive continental margins.关键词
洋陆转换带/构造演化/构造特征/被动大陆边缘/南海北部Key words
ocean-continent transition/tectonic evolution/tectonic characteristics/passive continental margin/northern South China Sea分类
天文与地球科学引用本文复制引用
赵宏超,朱筱敏,葛家旺,张维,施瑞生..洋陆转换带类型特征和形成机理及其在南海北部的表现特征[J].地质科技情报,2018,37(4):51-60,10.基金项目
国家科技重大专项(2017ZX05001-002-002) （2017ZX05001-002-002）
