准噶尔盆地侏罗系西山窑组沉降中心的分布及其构造控制  

DISTRIBUTION OF THE QUICK SUBSIDENCE CENTERS AND TECTONIC CONTROL ON THE JURASSIC XISHANYAO FORMATION IN JUNGGAR BASIN

作　　者：佟殿君[1] 任建业[1] 李亚哲[1] 

机构地区：[1]中国地质大学资源学院,湖北武汉430074

出　　处：《大地构造与成矿学》2006年第2期180-188,共9页Geotectonica et Metallogenia

基　　金：国家自然科学基金项目(40372067);中石化西部新区勘探指挥部联合攻关研究项目"准噶尔盆地中新生界层序地层;沉积体系;古地貌;高效储层研究及隐蔽油气藏预测"资助.

摘　　要：以准噶尔盆地21条典型的地震剖面上的329个取数据点资料为基础，应用EBM盆地模拟系统，对侏罗系西山窑组地层进行了沉降史回剥分析。从回剥的结果来看，盆地的沉降速率在不同时期显示出显著的不均一变化，其中在西山窑二段地层沉积时期的沉降速率在盆地南缘平均为70～90m／Ma，北缘及腹部地区只有30m／Ma左右；在西山窑一段地层沉积时期，盆地南缘的沉降速率则达到了120m／Ma，北缘及腹部相比前一阶段则没有太大变化。由此可以确定玛湖凹陷、乌伦古坳陷和昌吉凹陷是盆地在西山窑组地层沉积时期的沉降中心，盆地南缘的昌吉凹陷则是最主要和最大的的沉降中心。进一步分析，这些沉降中心的形成明显受到了周缘山系逆冲推覆作用的构造负载和盆地基底构造的制约，使盆地形成了隆坳相间的古地貌格局。由于沉降中心是低位三角洲砂体发育的重要部位，从而为隐蔽油气藏的勘探提供了方向。Based on the 329 data points that were acquired from 21 regional seismic profiles in Junggar Basin, the subsidence history of the Jurassic Xishanyao Formation strata was analyzed with the EBM basin modeling system. The backstripping results indicate that the subsidence rate of the basin displays remarkable inhomogeneous changes in different times and different areas. The subsidence rate for this basin is 70 -90 m/Ma in the southern part dur- ing the sedimentary stage of the second member of the Xishanyao Formation, but is only 30 m/Ma in the northern and central regions of the same basin. The subsidence rate for the southern part in this basin reaches 120 m/Ma during the sedimentary stage of the first member of Xishanyao Formation, and the subsidence rates for the northern and central regions remain stable when compared to that for the second member of the same formation. Based on these results, the three quick subsidence centers, i. e. , Mahu, Wulun and Changji depressions, during the sedi- mentary periods for the Xishanyao Formation in Junggar basin, can be identified, and the Changji depression in the southern part of the basin proves to show the maximum subsidence rate. The formation of these quick subsidence centers were obviously controlled by the tectonic load derived from the adjacent orogenic thrusting and preexisting tectonic blocks in the basin basement. The quick subsidence centers are the important areas for the lowstand delta sand body development, and can provide information for exploration of the subtle trap reservoirs.

关 键 词：准噶尔盆地 西山窑组 盆地模拟 沉降中心 隐蔽油气藏 

分 类 号：P618.130.2[天文地球—矿床学] P534.52[天文地球—地质学]