河南省嵩山区元古代嵩山群底部的主滑脱带  

A Master Décollement Horizon below the Proterozoic Songshan Group in Songshan Area, Henan Province

作　　者：索书田[1,2] 游振东[2] 闻立峰[2] 韩郁菁[2] Suo Shutian;You Zhendong;Wen Lifeng;Han Yujing(School of Earth Sciences and Resources,China University of Geosciences,Beijing 100083,China;School of Earth Sciences,China University of Geosciences,Wuhan 430074,China)

机构地区：[1]中国地质大学地球科学与资源学院,北京100083 [2]中国地质大学地球科学学院,湖北武汉430074

出　　处：《地球科学》2019年第5期1537-1543,共7页Earth Science

基　　金：国家自然科学基金项目(No.49972067);长江水利委员会综合勘测局项目

摘　　要：河南省嵩山区位于中朝地台南部,区内发育被2个角度不整合面分隔开的3个前寒武纪岩群,一个主滑脱带沿着嵩山群与登封群间不整合面发育.滑脱带之上的早元古代嵩山群形成近南北向的褶皱带,因此,嵩山群岩石在主滑脱带之上形成无根的独立构造.与滑脱带下伏的太古宙登封群很少有关系.主滑脱带厚4～30m,沿着主滑脱带,登封群角闪岩相岩石强烈退变质到绿片岩相矿物组合,主滑脱带发育在脆韧性过渡域.多尺度的观察指出,主滑脱带的形成受地壳成分分层导致的流变学分层性所制约,而且地层柱底部软弱面或地质界面是近水平的滑脱带发育的优选位置.显然,对滑脱带的发育还必须考虑水解弱化作用.The Songshan area of Henan Province is tectonically located in the southern part of the Sino-Korean craton. It is marked by the three groups of Precambrian separated by two unconformities. A master décollement horizon developed along the unconformity between the Dengfeng Group below and the Songshan Group above. The lower Songshan Group above the décollement horizon formed a nearly N-S trending folded belt. Therefore, Songshan Group structures have little relation with the Archaean Dengfeng Group below the décollement. The thickness of the master décollement horizon ranges from 4 to 30 m.Along this décollement horizon, the Denfeng Group amphibolite facies rock assemblage was strongly retrograded to that with superimposed greenschist facies mineral paragensis. The development of the décollment occurs near the brittle/ductle transition field. Our observations in various scales show that the formation of the décollement horizon is controlled by the rheological stratification which was induced by compositional layering of the crust. It is suggested that the weak interval or interface at the base of a stratigraphic sequence may be preferred structural level for the localization of sub-horizontal décollement zones. It is also clear that consideration of hydrolytic weakening is necessary to unravel the development of the décollement horizon.

关 键 词：嵩山区 流变学 变形分解作用 流变学分层性 滑脱带 角度不整合 水解弱化作用 构造地质 

分 类 号：P54[天文地球—构造地质学]