东秦岭-大别及两侧的大地构造旋回与油气勘探领域

TECTONIC CYCLES AND PETROLEUM EXPLORATION POTENTIAL IN THE EAST QINLING AND DABIE OROGENIC BELT

中元古代以来,东秦岭—大别造山带及两侧的盆地群经历了5大构造旋回。中条(吕梁)运动以后,华北地区形成了冀辽、豫陕、徐淮坳拉槽。晋宁运动后,随着Rodinia古大陆解体,隶属于原特提斯洋系的秦岭—大别洋逐渐形成,扬子和华北克拉通边缘经历了从大陆裂谷到被动大陆边缘的演化过程,加里东中期运动(中奥陶世中期)后从伸展体制转为聚敛体制,俯冲—碰撞山系与聚敛型盆地相间的格局形成。加里东晚期或海西早期,早期分离的陆块重新拼合,泥盆纪总体为堑—垒相间的构造格局。晚二叠世,南部部分地区形成了小规模裂谷群,中、晚三叠世印支运动后转为挤压体制,它们经历了拼贴—碰撞—压榨的过程,并于侏罗纪末燕山主幕达到极致。白垩纪以来,形成了陆内伸展—走滑—弱挤压为主的盆地群,盆地再次被以伸展、走滑方式肢解。5大盆地旋回形成了丰富多彩的盆地原型及组合,形成了条件迥异的油气成藏的物质基础,纵向上构成了8套成藏组合。受构造演化和热体制控制的有效烃灶和有效保存是研究区成藏富集的主控因素。南北两侧盆地形成了众多勘探领域,除已建成油气工业生产基地的南襄、江汉新生代盆地外,北侧地区包括洛—伊晚古—早中生代残留盆地、太康残留盆地、周口叠加复合盆地、信阳复合盆地等,造山带内部的有南襄盆地深层的古生界,南侧地区包括江汉平原区前第三纪复合盆地、宜昌—当阳古生代的改造型残留盆地、鄂东南冲断带下的影子盆地、大洪山冲断带下的影子盆地等领域。

The basin groups in both sides of the East different tectonic cycles since the Mesoproterozoic. Qinling and Dabie Orogenic Belt have experienced 5 After Zhongtiao （Luliang） Movement, the Jiliao, Yushaan and Xuhuai Aulacogens were formed in North China. With brokenness of the Rodinia ancient continent after the Jinning Movement, the Qinling--Dabie ocean, which was a part of the Tethyan ocean for a time, was gradually developed and the margin of the Yangtze Craton and North China Craton had gone through the evolution from continental rift to passive continental margin. The alternative pattern of subduction--collision mountain system and convergent basins was developed due to transferring of extend system to convergent system after the middle Caledonian movement （the Middle Ordovician）. In the late Caledonian or early Hercynian, the early detached continental blocks were combined together again. And the alternative graben-horst pattern was presented in the Devonian. Some small scales of rift groups were developed in the southern side of the orogenic belt in the Late Permian and it was changed to convergent system after the Middle and Late Triassic Indosinian Movement. They went through the collection, collision and compression process, which was maximized in the Yanshanian period of the end of the Jurassic. Since the Cretaceous, basin groups with domination of intracontinental extension--strike slip-- weak compression were developed and then the basins were destroyed by extension or strip slip again. The multiple combination of basin prototypes was formed by 5 basinal tectonic cycles, which formed basic conditions for hydrocarbon accumulation. There were 8 sets of combination of source, reservoir and seal in vertical section. The effective hydrocarbon kitchen and preservation, which was controlled by tectonic evolution and thermal system, was the critical factors for hydrocarbon accumulation. There are favorable potential for petroleum exploration of basins in both sides of the orogenic belt. Besides the Cenozoic Nanxiang and Jianghan oil producing basins, the potential regions include the Late Paleozoic to Early Mesozoic Louyu residual basin, the Taikang residual basin, the Zhoukou superimposed composite basin and Xinyang composite basin in the northern side, the deep seated Paleozoic in the Nanxiang basin of internal orogenic belt, and the pre-Tertiary Jianghan composite basin, the Paleozoic Yichang-Dangyang reformed residual basin, the shadow basins under the southeastern Hubei thrust belt and the Dahongshan thrust belt respectively, in the southern side of the orogenic belt.