天山南北缘前陆冲断构造对比研究及其油气藏形成的构造控制因素分析  

Comparative study of the foreland thrust belts of South and North Tianshan and implications for hydrocarbon accumulation

作　　者：郭召杰[1,2] 邓松涛[1,2] 魏国齐[3] 李本亮[3] 

机构地区：[1]北京大学造山带与地壳演化教育部重点实验室 [2]北京大学地球与空间科学学院,北京100871 [3]中国石油勘探开发研究院廊坊分院

出　　处：《地学前缘》2007年第4期123-131,共9页Earth Science Frontiers

基　　金：国土资源大调查项目(1212010611806);中国石油天然气集团公司"中国前陆盆地构造地质特征"课题

摘　　要：天山南北缘分别发育了库车前陆冲断带和乌鲁木齐前陆冲断带，南缘前陆冲断带发育4排褶皱冲断构造，北缘前陆冲断带发育3排褶皱冲断构造。天山南北缘前陆冲断构造形成时间的对比研究表明，南缘第一排构造带起始时间为23．3Ma，构造形变从山前由北向南依次展开；北缘第一排构造带的形成时限为10～8Ma，构造形变从山前开始由南向北依次展开。平衡剖面研究表明，天山南北缘地壳缩短率也存在明显差异，南缘前陆冲断带地壳缩短率为31％～59％，北缘前陆冲断带地壳缩短率为15．13％～23．74％，南缘构造缩短量要大于北缘，这种差异正是印度板块和欧亚板块碰撞的远距离构造效应从南向北传播造成的，也真实反映了天山的陆内造山过程。目前天山南缘前陆变形构造中已经发现几个规模较大的油气田，北缘虽有多处油气显示和油气田的发现，但数量和规模均较南缘少和小。天山南北缘生储盖等石油地质条件基本相似，大型油气藏形成的差异可能主要是由天山南北缘前陆冲断带启动时间的不同造成的。The Kuqa foreland developed in southern margin and UEruemqi foreland on the northern margin of the Tianshan orogen. There are four zones of fold-and-thrust belts on the southern margin and three on the northern margin. Comparative studies about the timing between the southern and northern foreland thrust belts indicate that the first structural belt in the southern margin of Tianshan began about 23.3 Ma ago and that the deformation propagated from north to south; whereas the first structural belt in the northern Tianshan began 10-8 Ma, and the deformation propagated northwards. Based on balanced section analysis, the shortening ratio in the southern Tianshan thrusts was 31%-0.59%, whereas in the northern margin 15.13%-23. 74%. Such differences may have originated from the far-field effects of the Indo-Tibetan collision, and are reflected in the intracontinental orogenic processes of Tianshan during the Cenozoic. A few large-scale oil and gas fields have been discovered in south Tianshan foreland thrust belts, but in the north, only small-scale oil and gas fields have been found. The source rocks, reservoir, cap rocks and traps between the northern and southern margins of Tianshan are quite similar, so these differences of large and small scale oil and gas fields may be mainly attributed to the different deformation time between the foreland thrust belts of the south and the north margins of Tianshan.

关 键 词：天山 前陆冲断带 南北缘对比 陆内造山 油气藏 

分 类 号：TE122.31[石油与天然气工程—油气勘探]