准噶尔盆地哈拉阿拉特山冲断带构造及找油意义

准噶尔盆地西北缘前陆冲断带是自石炭纪晚期发育起来的大型叠瓦冲断系统,哈拉阿拉特山冲断带为其冲断前锋构造带的东段。它由谢米斯台山单斜带、和什托洛盖盆地、哈拉阿拉特山叠瓦构造带和玛湖凹陷西斜坡4部分组成。该冲断带以古生界内部的滑脱面为界,分为上、下两套构造变形层：上构造变形层发育3-4排叠瓦状冲断构造,各冲断层交汇于古生界内部的滑脱面中;下构造变形层可能为10多个古生界断块叠加而成的双重构造。该冲断带宽约61km,构造缩短了53km,构造缩短率约46％．冲断前锋带的构造变形主要发生于三叠纪末,白垩纪时构造活动近于停止。前锋断裂带下盘的准原地系统中发育一系列断层转折褶皱、双重构造等,它们是准噶尔盆地西北缘下盘掩伏带的主要勘探目标,是在克拉玛依油田之下寻找“克拉玛依”的主要领域？

Thrust Belt Structure and Significance for Petroleum Exploration in Hala'alat Mountain in Northwestern Margin of Junggar Basin

The foreland thrust belt in northwestern margin of Junggar basin is a large-scale imbricated thrust system developed since Late Carboniferous.The Hala'alat mountain,the eastern segment of the leading thrust belt,is composed of four elements such as Xiemisitai monocline,the Heshituologai basin,the Hala'alat imbricated zone and the western slope of Mahu sag.The Hala'alat thrust system can be subdivided into the upper and lower units of distinct deformation styles bounded by slippage surface of Paleozoic strata.There exist three or four imbricated thrust zones in the upper unit,each of which pinches out the slippage surface.In the lower one,there could be ten more superimposed structures consisted of Paleozoic fault blocks.The Hala'alat thrust belt is about 61 km wide and shortened by 53 km with scalage of 46%.t.The structural deformation originated at the Late Triassic and ceased at the Early Cretaceous.In the para-autochthon of the lower block in the leading thrust occurred a series of fault-bend folds and superimposed structures,which are the most potential targets for oil-gas exploration in the near future in the northwestern margin of Junggar basin.It is concluded that the targets should be the major domains for discovering another "Karamay field" beneath existing Karamay oilfield.