新疆岩石圈三明治结构与油气资源

重力勘探是普查油气盆地常用的方法。利用重力研究岩石圈构造时，卫星重力具有独特的作用。它不但与自由空气重力异常相似。能直接反应岩石圈物质的积聚或亏损。可以获得较深处物质产生的重力场，还可以利用对重力场的分解处理，突出分层深度的异常特征，用以分析研究不同深度物质对重力场的贡献。根据对卫星重力异常的解释，可以将新疆地区岩石圈分成3层。最上层是中新生代陆相断陷盆地巨层。它的特点主要是四盆（伊宁盆地、准噶尔盆地、吐哈盆地和塔里木盆地）三山（阿尔泰山、天山和阿尔金山）的特殊景观。中间层是海相古生代盆山构造巨层。它是在印支-燕山期．强烈的挤压褶皱使地壳发生规律的平行线状排列盆山构造。最下层是低密度块体基底层。新疆地区岩石圈三明治构造的形成是因为在喜马拉雅期．印度板块自西南向东北的俯冲作用下．对古生代末已拼合成大陆的新疆地区进行改造，西天山的婆罗科努山、察布查尔山、阿拉沟山、额尔宾山、霍拉山等山系横向隆升。它们和南天山山脉一起。将新疆地区分割而成。从这项研究中得到启示，西部寻找油气资源不应局限于新生代盆地，而要考虑深部构造对地表出露盆山构造的控制。

Sandwich lithospheric structure of Xinjiang and its relation to petroleum resources

Gravity survey is a method commonly used in petroleum basin reconnaissance. Satellite gravity is favorable for studying lithospheric structure because from it we can not only get more deep information of inhomogeneity in the lithosphere but also resolve the gravity field into different layers to show the inhomogeneity at different depths. According to the satellite gravitational data, the lithosphere of the Xinjiang region may be divided into three megalayers. The top is a megalayer consisting of Meso-Cenozoic continental downfaulted basins, including the Yining basin, Junggar basin, Tarim basin, Tuha basin and Tarim basin, surrounded by the Altay, Tianshan and Altyn Tagh mountains. The middle megalayer consists of a series of Paleozoic marine parallel ranges and basins formed by strong compressional folding during the Indosinian-Yanshanian. The lowest megalayer is the low-density block basement. The sandwich lithospheric structure formed by reworking of the Xinjiang lithosphere beneath the continent assembled at the end of the Paleozoic due to Cenozoic northeastward subduction of the Indian plate. The Borohoro, Qapqal, Alagou, Erbeng and Horo mountains of the West Tianshan mountain system were uplifted transversely and they together with the South Tianshan mountain system divided the Xinjiang block into a series of new mountains and basins. This study leads to a conclusion that petroleum exploration in western China should not be restricted in Cenozoic basins but that we should consider the controls of deep structure on the basin-and-range structure exposed at the surface.