渤海海域前新生代基底时代归属与构造演化特征分析  

Chronostratigraphy of the pre-Cenozoic base and tectonic evolution characteristics in Bohai sea

作　　者：高坤顺 吴庆勋 彭靖淞 郭颖 马正武 GAO Kunshun;WU Qingxun;PENG Jingsong;GUO Ying;MA Zhengwu(CNOOC China Limited,Tianjin Branch,Tianjin 300459,China)

机构地区：[1]中海石油(中国)有限公司天津分公司

出　　处：《中国海上油气》2019年第4期19-26,共8页China Offshore Oil and Gas

基　　金：“十三五”国家科技重大专项“渤海海域勘探新领域及关键技术研究(编号:2016ZX05024-003)”部分研究成果

摘　　要：钻探揭示渤海海域前新生代基底地层结构在东西方向存在着明显的差异,前寒武纪地势西高东低、中生代末地势西低东高,构造演化具有明显的“跷跷板”现象。综合运用钻井、锆石U-Pb年代学、微古生物化石、三维地震等资料,明确了渤海海域前新生代基底时代归属,刻画了中生界、古生界残余地层分布特征。渤海西部前寒武系为变质岩基底,其年龄大致可以分为2 500 Ma左右和3 000 Ma左右两组,属于前中元古界;郯庐断裂东侧前寒武系古生物分析首次在渤海海域探井中发现新元古代疑源类化石,明确该区前寒武系碳酸盐岩为新元古界。郯庐断裂以西普遍残存古生界和局部残存侏罗系,郯庐断裂以东古生界几乎剥蚀殆尽,无侏罗系。南华纪Rodinia超大陆的裂解以及印支期华南、华北两板块剪刀式碰撞是造成研究区前新生代构造演化“跷跷板”现象的主要原因。Drilling data reveals that the pre-Cenozoic basement stratigraphic structure in the Bohai sea shows obvious differences between the East and the West. The pre-Cambrian terrain is high in the west and low in the east, and the late Mesozoic terrain is low in the west and high in the east. The tectonic evolution presents an obvious “seesaw” phenomenon. Based on the data of drilling, zircon U-Pb chronology, micropaleontological fossils and three-dimensional seismic data, the chronostratigraphy of the pre-Cenozoic basement in the Bohai sea is identified, and the distribution characteristics of the Mesozoic and Paleozoic residual strata are described. The pre-Cambrian in the western Bohai sea has a metamorphic rock basement, and their ages can be roughly divided into two groups of about 2 500 Ma and about 3 000 Ma, belonging to the pre-Mesoproterozoic;Neoproterozoic suspicious fossils were first discovered in exploration wells in the Bohai sea area by paleontological analysis of the Pre-Cambrian on the eastern side of the Tanlu fault, which verifies that the pre-Cambrian carbonate rocks in this area were in the Neoproterozoic. The widely remained Paleozoic and partially remained Jurassic are observed in the west of the Tanlu fault;the Paleozoic in the east of the Tanlu fault is almost completely eroded, and there is no Jurassic observed. Rodinia supercontinent breakup during Nanhua period and the scissor collision of the South China and North China plates during Indosinian period are the main reasons for the “seesaw” phenomenon of the pre-Cenozoic tectonic evolution in the study area.

关 键 词：渤海 前新生代 基底时代 构造演化 郯庐断裂 “跷跷板”现象 南华纪 锆石U-PB定年 疑源类化石 

分 类 号：TE121.2[石油与天然气工程—油气勘探]