地学前缘 ›› 2022, Vol. 29 ›› Issue (6): 277-290.DOI: 10.13745/j.esf.sf.2022.8.5

• 原型盆地复原理论与方法 • 上一篇    下一篇

华南晚中生代陆弧迁移与海域盆地演化

朱伟林1(), 徐旭辉2, 王斌3, 曹倩3, 陈春峰4, 高顺莉4, 冯凯龙1, 付晓伟1,*()   

  1. 1.同济大学 海洋地质国家重点实验室, 上海 200092
    2.中国石化石油物探技术研究院, 江苏 南京 211103
    3.中国石油化工股份有限公司 石油勘探开发研究院无锡石油地质研究所, 江苏 无锡 214131
    4.中海石油(中国)有限公司上海分公司, 上海 200030
  • 收稿日期:2022-07-07 修回日期:2022-08-01 出版日期:2022-11-25 发布日期:2022-10-20
  • 通讯作者: 付晓伟
  • 作者简介:朱伟林(1956—),男,教授,博士生导师,主要从事海域构造地质及石油地质研究。E-mail: zhuwl@tongji.edu.cn
  • 基金资助:
    国家自然科学基金项目(41702228);中国石油化工股份有限公司资助项目(P20027)

Late Mesozoic continental arc migration in southern China and its effects on the evolution of offshore forearc basins

ZHU Weilin1(), XU Xuhui2, WANG Bin3, CAO Qian3, CHEN Chunfeng4, GAO Shunli4, FENG Kailong1, FU Xiaowei1,*()   

  1. 1. State Key Laboratory of Marine Geology, Tongji University, Shanghai 200092, China
    2. Sinopec Geophysical Research institute, Nanjing 211103, China
    3. Wuxi Research Institute of Petroleum Geology, Sinopec, Wuxi 214131, China
    4. CNOOC China Limited (Shanghai), Shanghai 200030, China
  • Received:2022-07-07 Revised:2022-08-01 Online:2022-11-25 Published:2022-10-20
  • Contact: FU Xiaowei

摘要:

陆弧和弧前盆地是俯冲体系中具有密切联系的构造单元。中生代以来,华南受多期板块俯冲的控制,发育大规模岩浆岩带及海域广泛分布的弧前盆地。但陆域弧岩浆岩较少,海域又缺乏足够钻井,各时期陆弧的位置存在较大争议,同时,南海北部至东海一带弧前盆地也缺乏系统认识,因此,亟须新的研究思路深化对华南晚中生代俯冲体系和俯冲过程的认识。本文以前人研究为基础,对海域钻遇中生界的典型钻井进行了详细分析,系统开展了海域盆地区域构造和沉积对比,将弧前盆地发育与岛弧变迁相结合综合分析。结果表明早侏罗世—早白垩世陆弧位于南海北部—东海靠近陆域一侧,经历了早侏罗世局限陆弧、中晚侏罗世沿海陆弧带、早白垩世向海沟方向的迁移。在此过程中,华南海域弧前盆地群于中侏罗世正式形成,早白垩世发育盆缘角度不整合,粗碎屑相带向海沟方向迁移,晚白垩南海北部与东海各自进入新的构造体制,结束弧前盆地的发育。华南沿海海域中生代盆地的发育可为陆弧的展布提供重要约束,弧岩浆岩带的迁移控制了弧前盆地的演化。

关键词: 华南, 中生代, 弧前盆地, 陆弧, 俯冲体系

Abstract:

Forearc basins are closely linked to continental arcs in a subduction system. In southern China, widespread onshore magmatic belt and offshore forearc basins developed under multi-stage subduction since the Mesozoic. However, the arc migration pattern has been under hot debate, and the related forearc basins are little known because of limited offshore drilling and lack of access to onshore magmatic arc rock. Thus, new research designs are needed to observe the Late-Mesozoic subduction system/processes of southern China based on available data. In this paper, typical offshore wells containing Mesozoic layers are analyzed in detail; tectonics and sedimentation characteristics of offshore basins are systematically compared; and the development of forearc basins is analyzed in combination with the arc migration. Results show that the arc system extends roughly along the present-day coast of southern China from the Early Jurassic to Early Cretaceous: It mainly distributes in the southern East China Sea and extends to the northeastern South China Sea region in the Early Jurassic, then spreads widely southwards to the South China Sea in the Middle-Late Jurassic; since the Early Cretaceous it migrates eastward due to rollback of the subducted Paleo-Pacific slab. During this arc migration process, forearc basins are finally formed in the Middle Jurassic. And in response to the trenchward arc migration, angular unconformities in all forearc basins are formed and coarse clastic facies migrate trenchward in the Early Cretaceous. In the Late Cretaceous, the northern China Sea region is no longer in the subduction system and the forearc basin is replaced by regional unconformity; meanwhile, the East China Sea Basin becomes a backarc basin. Forearc basin evolution is primarily controlled by the migrating arc system, thus Mesozoic basins in the offshore South China Sea can provide important constraint on the regional arc migration pattern.

Key words: South China block, Mesozoic, forearc basin, continental arc, subduction system

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