从板缘碰撞到陆内造山:华南东南缘早古生代造山作用演化  

From Periphery Collision to Intraplate Orogeny:Early Paleozoic Orogenesis in Southeastern Part of South China

作　　者：徐亚军[1,2,3] 杜远生[1,2,3] Xu Yajun1,2,3 ,Du Yuansheng1,2,3(1.State Key Laboratory of Geological Processes and Mineral Resources ,China University of Geosclences ,Wuhan 430074,China 2.State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences ,Wuhan 430074, China 3.School of Earth Sciences ,China University of Geosciences ,Wuhan 430074,Chin)

机构地区：[1]中国地质大学地质过程与矿产资源国家重点实验室,湖北武汉430074 [2]中国地质大学生物地质与环境地质国家重点实验室,湖北武汉430074 [3]中国地质大学地球科学学院,湖北武汉430074

出　　处：《地球科学》2018年第2期333-353,共21页Earth Science

基　　金：国家自然科学基金项目(Nos.41472086;41772106);中央高校基本科研业务费专项资金(No.CUG2015039096)

摘　　要：华南的广西运动被认为是发生在早古生代的陆内造山作用,然而触发陆内变形的地球动力学机制仍然不清.广西运动形成了泥盆系与下伏岩石之间广泛的不整合面以及分布在局部地区的下古生界内部的多个不整合面.广西运动期间的构造热事件和古生物响应时间在460~380Ma,时间上对应于奥陶系和泥盆系之间的多个不整合,而分布在华南南缘的寒武系和奥陶系之间的不整合面(郁南运动)仅与少量的530~480Ma之间的变质事件相当,但是却同步于广泛分布在东冈瓦纳北缘的造山事件.华南南部寒武系-奥陶系不整合面上下的碎屑锆石年代学研究表明,早古生代华南与印度北缘相连,而三亚地块在寒武纪是澳大利亚西缘的一部分,直到奥陶纪才与华南拼合,同步于冈瓦纳最终的聚合.郁南运动之后,华夏板块处于冈瓦纳内部,来自冈瓦纳东缘造山作用的应力向大陆内部传播,在具有弱流变学性质的南华盆地聚集,导致盆地构造反转,触发了广西运动.早古生代的华南经历了从板缘碰撞(郁南运动)到陆内造山(广西运动)的演化过程.The Early Paleozoic Kwangsian Orogeny in South China is considered to have resulted from the intraplate deformation.However the geodynamic mechanism for the intraplate deformation remains unclear.The Early Paleozoic orogenesis is marked by a regional unconformity between pre-Devonian and Devonian strata and multiple stratigraphic unconformities developed within the Early Paleozoic sequence in the local areas of southeast South China.The Kwangsian magmatism,metamorphism and palaeontological variation are dated from 460 to 380 Ma.These events are in age linked to the multiple unconformities between the Ordovician and Devonian sequences.The unconformity between the Late Cambrian and Early Ordovician,named as the Yu＇nan Event in the southern margin of South China,is lack of contemporaneous petrological records,except for minor metamorphic rocks dated at 530-480 Ma.The range of this unconformity corresponds with timing of orogenic activity extending along the northern margin of East Gondwana.Derivation of detrital zircons from the Cambrian and Ordovician strata in thesouthern part of South China suggests that in the Cambrian South China constituted part of the north India and the Sanya Block presented currently in Hainan Island had not been part of South China but rather part of western Australia until the juxtaposition of South China and west Australia in the Early Ordovician.The event removed the Cathaysia Block from any spatial association with an active plate boundary and permitted the stresses sourced from the accretionary orogen in East Gondwana to propagate inboard across the supercontinent.These stresses localized along the site of the weak rheological Nanhua basin and consequently resulted in basin inversion and development of the intraplate Kwangsian Orogeny.The Early Paleozoic orogenesis in the southeastern part of South China evolved from periphery collision in the Yu＇nan Event to intraplate orogeny in the Kwangsian Orogeny.

关 键 词：广西运动 郁南运动 加里东运动 陆内造山作用 华南 构造地质 

分 类 号：P542[天文地球—构造地质学]