摘要
近年来,增生楔斜坡盆地作为一种罕见的含油气盆地逐渐受到重视。这类盆地构造特征复杂,目前勘探及研究程度相对较低,复杂断裂体系的成因一直存在争议。缅甸切杜巴增生楔斜坡盆地地震、地质资料相对较多,为这类盆地构造特征及断裂成因的研究提供了基础。为此,结合区域地质背景,以"纵向分(构造)层,横向分(段)块"思路为指导,明确了断裂分期发育类型;重点探讨了与增生楔构造带走向近平行的张性断裂成因,解决了以往断裂发育类型与应力形成机制相矛盾的问题;在此基础上,提出了引张应力的正断裂发育新模式。研究认为:切杜巴增生楔斜坡盆地发育南—北向压性断裂、北东-南西向扭张性和北西—南东向张性断裂三种断裂。受印度板块洋壳向西缅微地块的斜向俯冲作用控制,垂直于海沟轴向的挤压应力形成了南—北向压性断裂,发育大规模逆冲活动;平行于海沟轴向的剪切应力具右行走滑作用,形成具有调节作用的北东—南西向张性或扭张性断裂;增生楔斜坡盆地前缘与后缘的挤压逆冲断裂活动时,水平运动分量的差异性诱发拉张应力,是形成北西—南东向张性断裂的原因。该成果可为其他增生楔斜坡盆地研究提供参考。
In recent years,as a kind of rare oil/gas-bearing basin,accretionary wedge-slope basins have been paid more and more attention to.At present,exploration and research on this kind of basin is relatively less,so its complex structural features,especially the genesis of the complex fault system,have been debating.There are a lot of seismic and geological data about the Cheduba accretionary wedge-slope basin,which provide a basis for studying the tectonic characteristics and fault genesis of the basin.Based on the regional geology and under the guidance of the idea of"vertical(tectonic)layers and lateral(segments)blocks",firstly the fault type is defined in different stages;then the genetic mechanism of the extensional faults that are nearly parallel to the orientation of the accretionary wedge structural belt is discussed.This solves the contradiction between geological understanding and stress.On this basis,a new induced extension model of normal fault development is proposed,and three group of faults with different properties are identified in the Cheduba accretionary wedge-slope basin:S-N compressional faults,NE-SW extensional-transregional faults and NW-SE extensional faults.Controlled by oblique subduction of the oceanic crust of the Indian plate to the West Myanmar microplate,the compressive stress field perpendicular to the trench formed S-N compressional faults,and resulted in large-scale thrust activities,the shear stress parallel to the trench formed regulatory NE-SW extensional or transregional faults under the regional right-lateral strike-slip effect and the extensional stress field induced by different horizontal motion components during the activities of the accretionary wedge compression thrust fault zone in the front and back edge of the slope basin resulted in NW-SE extensional faults.The findings of this study are references to other accretionary wedge-slope basins.
作者
杨松岭
谢结来
YANG Songling;XIE Jielai(Research Institute of Exploration&Development Technology,CNOOC International Ltd,Beijing 100028,China;SPG Secretariat of CPS,BGP,CNPC,Zhuozhou,Hebei 072751,China)
出处
《石油地球物理勘探》
EI
CSCD
北大核心
2020年第5期1121-1130,936-937,共12页
Oil Geophysical Prospecting
基金
国家科技重大专项“海外重点盆地地球物理勘探关键技术攻关与应用”(2017ZX05032-003)资助
关键词
缅甸
切杜巴
增生楔
斜坡盆地
构造特征
张性断裂
引张作用
accretionary wedge
slope basin
structure style
extension fault
induced extensional effect
作者简介
杨松岭,北京市朝阳区太阳宫南街6号院中海油大厦A座808-2室中国海洋石油国际有限公司勘探开发技术研究院,100028。Email:yangsl@cnooc.com.cn;杨松岭,高级工程师,1971年生,1994年获中国地质大学(北京)地质与地球物理复合专业学士学位,现就职于中国海洋石油国际有限公司勘探开发技术研究院,主要从事海外油气勘探的地质综合研究。
