桐柏-大别杂岩的塑性流变机制探讨——基于几何结构、运动性质与动力学的启示  

The Plastic Rheological Mechanism of Tongbai-Dabie Complex:Enlightenment Based on the Geometric Structure,Motion Properties,Tectonic Attributes and Dynamics

作　　者：李海龙 向必伟 王微 李加好[4] 宋传中[4] 刘程 林少泽 陈磊 赵文俊 吴敏行 张夏添 LI Hailong;XIANG Biwei;WANG Wei;LI Jiahao;SONG Chuanzhong;LIU Cheng;LIN Shaoze;CHEN Lei;ZHAO Wenjun;WU Minxing;ZHANG Xiatian(School of Earth Sciences,East China University of Technology,Nanchang 330013,Jiangxi,China;National Key Laboratory of Prospecting,Mining and Remote Sense Detecting on Uranium Resources,East China University of Technology,Nanchang 330013,Jiangxi,China;State Key Laboratory of Nuclear Resources and Environment,East China University of Technology,Nanchang 330013,Jiangxi,China;School of Resources and Environmental Engineering,Hefei University of Technology,Hefei 230009,Anhui,China)

机构地区：[1]东华理工大学地球科学学院,江西南昌330013 [2]东华理工大学,铀资源探采与核遥感全国重点实验室,江西南昌330013 [3]东华理工大学,核资源与环境国家重点实验室,江西南昌330013 [4]合肥工业大学资源与环境工程学院,安徽合肥230009

出　　处：《大地构造与成矿学》2024年第6期1188-1210,共23页Geotectonica et Metallogenia

基　　金：国家自然科学基金项目(41472194、42162019、42102269、42362028);江西省教育厅科学技术研究项目(GJJ2200756)联合资助。

摘　　要：桐柏-大别造山带形成于印支期华北板块和扬子板块俯冲碰撞构造背景下,主要受近SN向挤压作用。在几何形态上,该造山带表现为巨型的背形构造,且在垂向上具有分层结构,层与层之间通过一种特殊的滑脱面连接,根据滑脱面上的拉伸线理和热擦痕可知,层与层之间发生了错动。殷店-马垅剪切带和晓天-磨子潭剪切带是背形构造中的一个构造层,由于后期的风化剥蚀,造山带背形构造的顶部部分被剥蚀,使得桐柏杂岩和大别杂岩出露,故而只在背形构造的两侧保留剪切带。桐柏-大别造山带的管状流变开始于210 Ma左右,此时为深部的塑性流变,在180 Ma左右随着板块挤压碰撞作用的终结,造山带总体处于“静默”状态。由于差异流变界限的存在形成了背形强变形带(相比管道外),界限以内发生塑性流变,界限以外则是相对之下的固体运动。随着南北剪切带的形成,管状流变虽然在继续,但是随着深部桐柏-大别杂岩由西向东的流变在东部积累形成大别山,使管状流变强度不断减弱,150 Ma左右,中国东部开始了广泛的燕山期岩浆活动,一直到130 Ma左右,剪切活动和管状流变才慢慢衰减停止。剪切活动和管状流变结束以后,岩浆活动强烈,直到110 Ma以后,岩浆活动逐渐减弱,区域开始发生以垂向抬升为主的强烈伸展活动,奠定了桐柏-大别造山带穹隆状的几何特征。在后期新生代的风化剥蚀作用下以及小规模的构造活动改造,使得桐柏-大别造山带形成了当今的构造格局。The Tongbai-Dabie orogenic belt is formed under the background of the collision and compression between the North China block and the Yangtze block after the Indosinian period,and it is mainly subjected to the nearly north-south trending compressional stress.The geometry of the Tongbai-Dabie orogenic belt is a large antiform structure.Moreover,the antiform structure has a layered structure in the vertical direction,and there is a special detachment surface in-between the layers.According to the mineral stretching lineation and heat scratches on the detachment surface,it can be inferred that a slide occurs between the layers.The Yindian-Malong and Xiaotian-Mozitan shear zones belong to the same tectonic layer of the antiform structure,which formed the antiform structure in the Tongbai-Dabie orogenic belt during the collision between the North China Block and the Yangtze Craton.Because of the later weathering and denudation,the top part of the antiform structure was eroded,leading to the exposure of the Tongbai-Dabie Complexes;therefore,only the two shear zones on the side of the antiform structure were preserved.The plastic rheology events of the Tongbai-Dabie orogenic belt started at approximately 210 Ma,which was the deep plastic rheology at that time.At approximately 180 Ma,with the end of plate compression and collision,the orogenic belt was generally in a“silent”state.Due to the existence of differential rheological boundaries,a back shaped strong deformation zone(compared to the outside of the pipeline)is formed,where plastic rheology occurs within the boundary,while solid motion occurs relatively beyond the boundary.With the formation of the north-south shear zone,although the tubular rheology continues,as the deep Tongbai-Dabie Complex flows from west to east and accumulates into the Dabie Mountains in the east,the strength of the tubular rheology is weakened.By around 150 Ma,the extensive Yanshanian magmatic activity began in Eastern China,and by around 130 Ma,the shear activity and tubular rheology g

关 键 词：桐柏-大别造山带 背形构造 塑性流变 构造演化 

分 类 号：P541[天文地球—构造地质学]