论江南—雪峰基底拆离式构造——南方构造问题之一

BASEMENT DECOUPLING STRUCTURE IN JIANGNAN-XUEFENG——SERIES 1 OF THE SOUTHERN STRUCTURE STUDIES

丁道桂 郭彤楼 胡明霞 刘运黎

Ding Daogui Guo Tonglou Hu Mingxia Liu Yunli

中国石油化工股份有限公司, 石油勘探开发研究院, 无锡石油地质研究所, 江苏, 无锡, 21415 2. 中国石油化工股份有限公司, 南方勘探开发分公司, 昆明, 650200 3. 成都理工大学, 成都, 610059

Wuxi Research Institute of Petroleum Geology, Research Institute of Petroleum Exploration and Production, SINOPEC, Wuxi, Jiangsu 214151, China 2. Southern Exploration and Production Company, SINOPEC, Kunming, Yunnan 650200, China 3. Chengdu University of Technology, Chengdu, Sichuan 610059, China

基底拆离式构造是大陆板块边缘受到俯冲、消减、挤压和缩短作用时,在大陆板块内部的反应,即地壳内部受到水平挤压作用时,沿壳内"低速带"、"高导层"等软弱带产生多层次的拆离。这些发育在变质基底内的大型韧性剪切带把岩石圈板块的地壳拆离成若干"薄岩席",并沿拆离面发生大规模的滑移和推覆,使得板内古生界盆地的沉积盖层产生侏罗山式的褶皱与叠复,层间出现剪切与滑脱等由强及弱的递进变形改造和缩短,以达到中、上地壳剖面的平衡。文中讨论了江南—雪峰山"隆起带"的性质,认为它既不是造山带的"厚皮构造",也不属于沉积盖层褶皱的"薄皮构造"范畴,而是属于"过渡型的基底拆离式"的构造属性。它是在印支—早燕山运动期间由南东向北西(同时派生由南向北,由东向西)进行基底拆离和推覆的,成为控制整个扬子海相中古生界盆地改造变形的动力学来源和主导因素,同时也控制了海相油气的形成与聚集。

The basement decoupling structure is the reaction in continent plate when the margin of continent plate is subducted,subdued,extruded and shortened.Extruded under horizontal effect,the earth crust is decoupled along such flabby zones as "low velocity zone" and "high conductivity formation".These huge flexile shear zones in metamorphic basement divide the lithosphere plate into several "thin sheets".Along the decoupling surface,great scale slide and nappe take place,resulting in the Jura-type fold and superimposition of sedimentary cover of the Paleozoic basin within plate.Interbed shear slide and distorted rebuilding and shortening from strong to weak take place so as to balance the middle and upper crusts.It is discussed in this paper the attribute of Jiangnan-Xuefeng uplift which is neither "thick-skinned structure" of orogenic belt nor "thin-skinned structure" of sedimentary cover fold but "intergradational basement decoupling structure".From Indosinian to early Yanshanian,decoupling and nappe take place from SE to NW(S to N,E to W at the meanwhile).It is the dynamic source and domination controlling deformation of Yangtze marine facies Meso-Paleozoic basins and at the same time it controls the generation and accumulation of marine facies petroleum.

国家"七五"重点科技攻关54—02项目01—01—03专题;中国石油化工股份有限公司油田部南方海相油气勘探项目经理部项目(H—2000—025)

https://doi.org/10.11781/sysydz200702120