湖南省印支运动应力场特征及其动力机制  

Characteristics and Dynamic Mechanisms of the Stress Field of the Indosinian Movement in Hunan Province

作　　者：柏道远 李彬 曾广乾 杨俊 BAI Dao-Yuan;LI Bin;ZENG Guang-Qian;YANG Jun(Hunan Institute of Geology Survey,Changsha 410016,Hunan,China)

机构地区：[1]湖南省地质调查所,湖南长沙410016

出　　处：《华南地质》2024年第2期252-269,共18页South China Geology

基　　金：湖南省地质院科研项目(201917、HNGSTP202302、HNGSTP202306、HNGSTP202323);湖南省自然资源厅重大项目(2023-02)。

摘　　要：长期以来,华南中部湖南印支运动的构造表现暨上古生界盖层褶皱的形成时代备受研究者关注,但至今仍存在显著的认识分歧。鉴此,本文在作者多年研究成果基础上,对湖南省印支运动早、晚两幕褶皱相关的区域应力场特征及厘定依据进行了系统总结和阐释,并探讨了应力场形成的动力机制以及印支运动的其他相关问题,取得以下主要认识:(1)印支运动早幕发生于中三叠世后期,区域最大主应力方向变化很大,省境中带,自湘西北往南东至湘中、湘东南东部,总体由NNW向—近SN向→NW向→NWW向弧形偏转;南西带,由湘西南的NW向→湘中南的EW向→湘东南西部的EW向变化;北东带,由湘东北的SN向转为湘东地区的NW向、NWW向。印支运动晚幕发生于晚三叠世,区域最大主应力为SN向,湘中局部地区为NNE向。(2)印支运动早幕区域挤压应力场主要与华北地块向南、思茅-印支地块向北以及古太平洋板块向北西的挤压有关,呈NE向—NNE向展布的各次级块体之间的继发性陆内汇聚、NW向基底隐伏断裂左行走滑以及加里东期越城岭和苗儿山花岗质岩体的阻挡等也具有重要的控制作用。印支运动晚幕SN向区域挤压应力场与华北地块向南的挤压、思茅-印支地块向北的挤压有关,局部NNE向最大主应力与NW向常德-安仁、郴州-邵阳基底隐伏断裂右行走滑有关。(3)古太平洋板块的NW向挤压或许是华南印支期NE向褶皱最好的动力学解释;湘中地区NE向褶皱发育程度远高于EW向褶皱,是前者早于后者的重要证据;湘中高挂山—四明山NE向构造隆起带是印支运动晚幕SN向挤压下,先期NE向构造软弱带横向压扁和垂向拉伸而形成。For a long time,the manifestation of the Indosinian Movement and the formation age of the folds in the Upper Paleozoic cap in Hunan Province in central South China have attracted the attention of researchers,but there are still significant differences in understanding of this.Given this,based on the author's years of research achievements,this paper has systematically summarized and explained the regional stress field characteristics and determination basis of the Early and Late Indosinian Movement in Hunan Province,and explores the dynamic mechanisms of stress field formation and other related issues of the Indochinese Movement,achieving the following main understandings.(1) The Early Indosinian Movement occurred in the late Middle Triassic,with significant changes in the direction of regional maximum principal stress.In the middle belt of Hunan Province,from northwestern to central Hunan and to the east part of southeastern Hunan,the direction of regional maximum principal stress generally deviated in an arc from NNW-near SN to NW and finally to NWW;in the southwest belt,the direction changed from NW in southwestern Hunan to EW in central-southern Hunan,and then to EW in western part of southeastern Hunan;in the northeast belt,it changed from SN in northeastern Hunan to NW and NWW in eastern Hunan.The Late Indosinian Movement occurred in the Late Triassic,with the regional maximum principal stress direction of SN,and locally NNE in some areas of central Hunan.(2) The compressive stress field in the Early Indosinian Movement was mainly related to the southward compression of the North China Block,the northward compression of the Simao-Indochina Block,and the northwestward compression of the Paleo-Pacific Plate.The secondary intracontinental convergence between various secondary blocks distributed in a NE-NNE direction,the sinistral strike-slipping of NW-trending basement hidden faults,and the obstruction of the Caledonian Yuechengling and Miao'ershan granitoids also played an important controlling role.The regio

关 键 词：印支运动早幕 印支运动晚幕 区域挤压应力场 动力机制 华南地块 湖南 

分 类 号：P541[天文地球—构造地质学]