中西非叠合裂谷盆地形成与演化  

Formation and evolution of West and Central African superimposed rift basins

作　　者：张光亚[1] 黄彤飞 刘计国[1] 李曰俊[2] 杜业波[1] 余朝华 张新顺 喻志骅 ZHANG GuangYa;HUANG TongFei;LIU JiGuo;LI YueJun;DU YeBo;YU ZhaoHua;ZHANG XinShun;YU ZhiHua(PetroChina Research Institute of Petroleum Exploration and Development,Beijing 100083,China;Institute of Geology and Geophysics,Chinese Academy of Sciences,Beijing 100029,China;China National Oil and Gas Exploration and Development Company Ltd.,Beijing 100034,China)

机构地区：[1]中国石油天然气股份有限公司勘探开发研究院,北京100083 [2]中国科学院地质与地球物理研究所,北京100029 [3]中国石油国际勘探开发有限公司,北京100034

出　　处：《岩石学报》2022年第9期2539-2553,共15页Acta Petrologica Sinica

基　　金：中国石油天然气股份有限公司科学研究与技术开发项目(2021DJ3103);重大科技专项(2015D-0909)联合资助.

摘　　要：中西非叠合裂谷盆地是发育在前寒武系结晶基底之上的中-新生代多旋回陆内裂谷盆地,以往的研究主要针对跨不同世代、不同性质原型盆地叠合构成的盆地,但对于由多期裂谷活动形成的叠合裂谷盆地,其叠合改造模式及其动力学机制研究尚不深入。本文基于近年来在中西非裂谷系油气勘探开发中获得的有关地质、地球物理和地球化学资料,结合前人研究成果,重点研究了中西非裂谷系盆地演化阶段、不同阶段原型盆地发育特征、多期叠合、改造类型、模式及其动力学背景。研究表明,自冈瓦纳大陆裂解以来,受非洲大陆周缘板块构造事件及西北非陆块、东北非陆块和中南非陆块间相对运动的影响,中西非裂谷系盆地大致经历了早白垩世、晚白垩世、古近纪-新近纪三个构造演化阶段。早白垩世阶段断裂活动最为强烈,是裂谷盆地主干断裂形成时期,在不同构造部位发育了裂谷盆地、走滑-拉分盆地和坳拉谷盆地三类原型盆地,盆地基底沉降速率最大,地层沉积充填厚度大,沉积体系均为陆相碎屑沉积,奠定了裂谷盆地形成演化的基础;晚白垩世阶段,早白垩世原型盆地继承发展,但盆地间裂谷发育程度差异性凸显,沉积充填特征差异变大,由早白垩世统一陆相沉积体系演变为海、陆相并存的沉积体系;古近纪-新近纪阶段,该裂谷系盆地发育变得更为复杂,差异性进一步加剧,裂谷作用、走滑作用和挤压反转作用在不同盆地同步发生,期间可持续发育裂谷盆地或发生挤压反转和构造变形。根据三个阶段原型盆地在盆地性质、沉积充填、垂向叠加、构造变形等方面的差异,将中西非叠合裂谷盆地划分为“继承叠合型”和“反转改造型”两类,进一步划分为“早断型”、“继承型”、“叠加型”、“晚断Ⅰ型”、“晚断Ⅱ型”以及“裂谷盆地反转型”、“走滑-拉分盆�West and Central African superimposed rift basins are Meso-Cenozoic multicycle intra-continental rift basins developed on the Precambrian crystalline basement.Previous studies mainly focused on the formation and superimposition process of several prototype basins developed in a single superimposed basin,but it is rarely documented that research on the different contemporaneous complex superimposed rift basins in the same tectonic region as well as those superimposed rift basins with different prototypes basins in vertical through time has been carried out.Based on the geological,geophysical,and geochemical data obtained during the oil and gas exploration activities in the West and Central African superimposed rift basins recently,combined with the previous research results,this paper focuses on the basin evolution,formation and superimposition process of prototype basins through time of the West and Central African superimposed rift basins.Results show that since the breakup of Gondwana,affected by the relative movements among the Northwest African block,the Northeast African block,and the Central and South African block of the African continent and the tectonic events of the surrounding plates,the West and Central African superimposed rift basins have roughly experienced three phases of tectonic evolution,namely,Early Cretaceous,Late Cretaceous and Paleogene-Neogene.Early Cretaceous evolution phase is the key period of the formation and evolution of the rift basins,during which the boundary faults of these rift basins develop and act intensively.Three types of prototype basins are developed,including rift basin,strike-slip pull-apart basin and aulagu basin.Basement subsidence of these rift basins is the largest with the fastest subsidence rate among the total subsidence.Lower Cretaceous sedimentary filling has the largest percent in the total filling,and sedimentary systems in whole rifts system are non-marine clastic deposition.During Late Cretaceous evolution phase,these early prototype basins were inherited.H

关 键 词：中西非 构造演化 叠合盆地 裂谷盆地 走滑-拉分盆地 反转构造 

分 类 号：P542[天文地球—构造地质学] P618.13[天文地球—地质学]