地学前缘 ›› 2022, Vol. 29 ›› Issue (6): 291-304.DOI: 10.13745/j.esf.sf.2022.8.9

• 原型盆地复原理论与方法 • 上一篇    下一篇

扬子板块北缘新元古代盆地结构与马槽园群归属研究

李路顺1(), 汪泽成2, 肖安成1,*(), 胡安平3, 陈友智4, 王芊芊5   

  1. 1.浙江大学 地球科学学院 浙江省地学大数据与地球深部资源重点实验室, 浙江 杭州 310027
    2.中国石油勘探开发研究院, 北京 100083
    3.中国石油杭州地质研究院, 浙江 杭州 310023
    4.中国石油集团 东方地球物理勘探有限责任公司 西南物探研究院, 四川 成都610213
    5.浙江大学医学院, 浙江 杭州 310027
  • 收稿日期:2022-07-07 修回日期:2022-08-03 出版日期:2022-11-25 发布日期:2022-10-20
  • 通讯作者: 肖安成
  • 作者简介:李路顺(1998—),男,硕士研究生,构造地质学专业。E-mail: 21938014@zju.edu.cn
  • 基金资助:
    中国石油天然气股份有限公司勘探开发研究院项目(RIPED-2019-JS-698);国家“十三五”重大专项项目“含油气盆地深层构造及其控制作用(2017ZX05008-001);深层古老含油气系统成藏规律与目标评价项目(2017ZX05008-005)

Tectonics of the Neoproterozoic basin and age of the Macaoyuan Group on the northern margin of the Yangtze Block

LI Lushun1(), WANG Zecheng2, XIAO Ancheng1,*(), HU Anping3, CHEN Youzhi4, Wang Qianqian5   

  1. 1. Zhejiang Key Laboratory of Geoscience Big Data and Deep Earth Resources, School of Earth Sciences, Zhejiang University, Hangzhou 310027, China
    2. Research Institute of Petroleum Exploration & Development, PetroChina, Beijing 100083, China
    3. Hangzhou Research Institute of Geology, PetroChina, Hangzhou 310023, China
    4. Southwest Geophysical Research Institute, BGP, CNPC, Chengdu 610213, China
    5. Zhejiang University School of Medicine, Hangzhou 310027, China
  • Received:2022-07-07 Revised:2022-08-03 Online:2022-11-25 Published:2022-10-20
  • Contact: XIAO Ancheng

摘要:

扬子北缘的鄂西和渝东地区分布有2个关键的元古宇出露的大地构造单元,即西侧的神农架隆起与东侧的黄陵隆起。扬子板块北缘经历长期的沉积与变形改造,形成了现今的大巴山和川东冲断体系。本文利用沉积学与地球物理综合方法对该区元古宙深层盆地格架进行研究,通过对裂谷断裂边界与内部盆地结构的识别揭示出西侧的南充—竹山、东侧的忠县—宜昌裂谷带的展布形态,认为它们是新元古代罗迪尼亚超大陆裂解过程中发育的裂谷体系,神农架隆起和黄陵隆起则为分隔2个古裂谷带的同期侧翼差异隆升地块。同时通过激光原位U-Pb同位素定年技术对位于神农架南侧的年代长期有争议的马槽园群砾岩开展年代学与沉积学研究,利用其中的同沉积白云岩夹层和上覆层白云质角砾岩进行碳酸盐岩测年,获得(759.2±17.6) Ma和(566.8±13.8) Ma的年龄,证实了马槽园群为南华纪裂谷填充沉积,形成于忠县—宜昌裂谷西侧的斜坡沉积环境。由此建立了马槽园群沉积序列,结合裂谷带及隆起处的多条沉积剖面重建了扬子板块北部新元古代裂谷盆地沉积填充格架。

关键词: 扬子北缘, 马槽园群, 新元古代, 裂谷格局

Abstract:

There are two key tectonic units—the Shennongjia uplift in the west and the Huangling uplift in the east—exposed in the Proterozoic in western Hubei and eastern Chongqing on the northern margin of the Yangtze Block, where prolonged sedimentation and extended deformation form the current Dabashan and East Sichuan thrust systems. In this paper, the regional Proterozoic deep basin framework is studied using comprehensive sedimentological and geophysical methods. Through the identification of rift fault boundary and internal basin tectonics, the topography of the Zhushan mountain of Nanchong in the west and the Yichang rift zone of Zhongxian in the east is revealed—they are considered to be the rift systems developed during the breakup of the Neoproterozoic Rodinia supercontinent, and separated by a rift block consisting of the Fenghuangshan anticline, Shennongjia uplift and Huangling uplift. Meanwhile, the chronology and sedimentology of the long-disputed Macaoyuan conglomerate on the south side of Shennongjia are studied by in-situ U-Pb isotope dating method. Dating of carbonate rocks yields ages of 759.2±17.6 Ma and 566.8±13.8 Ma, which confirms the Macaoyuan Group was filled in the Nanhua rift and formed on a depositional slope on the west side of the Zhongxian-Yichang rift. Subsequently, the sedimentary sequence of the Macaoyuan Group is established, and then the sedimentary filling framework of the Neoproterozoic rift basin in the northern Yangtze Plate is reconstructed by combining several sedimentary profiles across the rift belt and uplift.

Key words: northern margin of the Yangtze Block, Macaoyuan Group, Neoproterozoic, rift tectonics

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