华南加里东期“非典型”造山特征及关键科学问题  

Characteristics and key scientific issues of the“atypical”Caledonian orogeny in South China

作　　者：侯明才[1,2] 齐靓 李夔洲 黎乐 任强 赵子霖 胡生平 胡佳驹 王铸炜 HOU Mingcai;QI Liang;LI Kuizhou;LI Le;REN Qiang;ZHAO Zilin;HU Shengping;HU Jiaju;WANG Zhuwei(State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation&Institute of Sedimentary Geology,Chengdu University of Technology,Chengdu,Sichuan 610059,China;Key Laboratory of Deep-time Geography and Environment Reconstruction and Applications of Ministry of Natural Resources,Chengdu University of Technology,Chengdu,Sichuan 610059,China;College of Earth and Planetary Sciences,Chengdu University of Technology,Chengdu,Sichuan 610059,China)

机构地区：[1]油气藏地质及开发工程国家重点实验室,成都理工大学沉积地质研究院,四川成都610059 [2]自然资源部深时地理环境重建与应用重点实验室,成都理工大学,四川成都610059 [3]成都理工大学地球与行星科学学院,四川成都610059

出　　处：《地质学报》2024年第12期3503-3529,共27页Acta Geologica Sinica

基　　金：国家自然科学基金项目(编号42330513)资助的成果。

摘　　要：典型加里东运动指的是晚志留纪时期亚匹特斯洋关闭导致现今大西洋两侧出现的一系列区域不整合、强烈变质-变形和花岗岩侵位事件的大陆碰撞和远程推覆作用。华南在该时期也发生了明显的造山作用,但却与经典的加里东运动相去甚远。本文在系统总结了华南加里东期造山表现的基础上,通过对比典型加里东造山带,明确提出了华南加里东期“非典型”造山的概念及特征:空间上自东向西逐渐变新大规模面状花岗岩、非线状花岗岩且缺乏典型火山岛弧属性基性岩及大洋残余物,区域性角闪岩相—绿片岩相变质,缺乏典型的高温麻粒岩及线状高压—超高压变质岩带,存在多期次多阶段的空间分异但同一期次华南板块内部沉积建造连续过渡—不存在截然的空间分界线。另一方面,从探讨“非典型”造山形成的地球动力方向、来源与动力学机制的角度,提出了需要进一步解决的关键科学问题:以雪峰山—九岭山一线为界,泥盆系与前泥盆系接触关系自东向西表现为高角度不整合、低/微角度不整合向平行不整合的过渡,前泥盆系变形主要表现为从南到北由轴迹近E-W向为主转变为轴迹近NE-SW向为主的不同形态的褶皱,但仍需有效手段排除印支期或燕山期构造运动对加里东期褶皱变形的影响,对动力学机制的进一步探讨也需在此基础上进行;华南板块在早古生代“非典型”造山过程中与其他板块之间的位置关系是如何,华南板块尺度的沉积响应如何与全球尺度的构造古地理格局耦合;这一种“非典型”造山的动力学过程究竟是华南内部俯冲-碰撞/斜向碰撞-走滑造山模式,华南板块内部的板内造山,华南板块与东冈瓦纳板块俯冲-碰撞造山模式,还是东、西华夏地块之间的洋-陆碰撞造山。通过回答上述问题,可为探讨华南早古生代造山的地质过程提供重要依据,同时为�The representative Caledonian Orogeny is defined as the late Silurian continent-continent collision and remote-thrusting associated with the closure of the Iapetus Ocean,resulting in a series of regional unconformities,intense metamorphism,deformation and granitic intrusions on the borders of the present Atlantic Ocean.The South China block is also considered to have experienced significant early Paleozoic movements the but bears little resemblance to the classical Caledonian Orogeny.In this paper,we propose the concept and characteristics of the“atypical”Caledonian orogenesis in South China through a comparison with representative Caledonian Orogen:①Large-scale gradually younger westward planar and non-linear granites but lacks of typical arc-affiliated basic rocks and oceanic relics.②Regional amphibolite-greenschist facies metamorphism with an absence of typical high-temperature granulites and linear high-ultrahigh-pressure metamorphic rock belts.③Spatial differentiation of multi-stages sedimentary formations,yet there were no clear boundaries and continuous transition of sediments within the block at the same stage.We also propose some crucial scientific issues that need further resolution from the perspective of the geodynamic mechanisms:①The contact relationship between Devonian and pre-Devonian strata transitions from high-angle and low/minor angle unconformity to parallel unconformity through east to west devided by Xuefeng Mountains-Jiuling,and the deformation of pre-Devonian formations manifested in different forms of folds with axial traces from nearly E-W-oriented in the south to NE-SW in the north,however,effective means are still needed to eliminate the influence of subsequent Indosinian or Yanshanian movements,which is the basis of further discussion on geodynamic mechanisms.②The positional relationship between South China and other plates during the early Paleozoic,and coupling relation between sedimentary records at the plate scale and the global tectonic.③Whether the dynamic proce

关 键 词：华南 早古生代 加里东 “非典型”造山 

分 类 号：P542.2[天文地球—构造地质学]