幕阜山岩体北缘鄂南地区构造特征与构造控矿作用  

Structural characteristics and tectonic controls on mineralization in the northern margin of the Mufushan pluton,southern Hubei region

作　　者：林子晗 夏元 张航川 徐先兵[1] LIN Zihan;XIA Yuan;ZHANG Hangchuan;XU Xianbing(School of Earth Sciences,China University of Geosciences(Wuhan),Wuhan 430074,China;Fourth Geological Brigade,Hubei Provincial Geological Bureau,Xianning Hubei 437100,China)

机构地区：[1]中国地质大学(武汉)地球科学学院,武汉430074 [2]湖北省地质局第四地质大队,湖北咸宁437100

出　　处：《地质科技通报》2025年第2期257-269,共13页Bulletin of Geological Science and Technology

基　　金：湖北省自然科学基金联合基金项目(2023AFD229)。

摘　　要：江南造山带中段幕阜山地区发育规模巨大的早白垩世Li-Be-Cs-Nb-Ta等稀有金属和Pb-Zn-Cu-Au-Sb等有色金属岩浆-热液成矿系统。幕阜山岩体南、北缘的湘东北和鄂南地区具有相同的成矿物质基础,但现有矿产勘探成果差距明显,可能是构造变形差异所致。本研究通过构造解析、古应力场反演以及矿床分布规律,探讨了鄂南地区的构造控矿作用。构造解析表明E-W走向江南断裂形成于新元古代,保存了三叠纪由S向N的逆冲作用、晚白垩世断层上盘向SE的正断作用和古近纪E-W走向左行剪切作用;而NE-SW走向长坪断裂形成于中侏罗世燕山运动,记录了早白垩世晚期左行走滑、晚白垩世正断作用和古近纪晚期右行走滑。基于断层滑移矢量反演的古应力场揭示鄂南地区经历了早白垩世晚期走滑(近N-S向最大主应力)、晚白垩世NW-SE走向伸展、古近纪早期走滑(NE-SW向最大主应力)和古近纪中-晚期NE-SW走向伸展的应力场演化历史。结合研究区的金属矿床分布特征,认为鄂南地区NE-SW走向主干断裂的次级近平行断裂或与其相交的NW-SE走向和近E-W走向断裂具有较好的金属矿产勘探潜力。[Objective]An intensive Early Cretaceous magmatic-hydrothermal metallogenic system developed in the Mufushan area of the central Jingnan Orogen.This orogenic belt in the South China Block formed through the accretion and subsequent collision of the Yangtze and Cathaysia blocks during the early Neoproterozoic,resulting in the formation of rare metal deposits(Li-Be-Cs-Nb-Ta)and nonferrous metal deposits(Pb-Zn-Cu-Au-Sb).[Methods]This study investigates the structural control of polymetallic deposits in southern Hubei Province utilizing structural analysis,paleostress inversions of fault-slip data,and the spatial distribution of polymetallic ore deposits.[Results]Structural analysis revealed that the Jiangnan fault,striking E-W and originating in the Neoproterozoic,exhibits Triassic top-to-the-north thrusting,Late Cretaceous oblique normal faulting,and Paleogene left-lateral strike-slip motion.The NE-striking Changping fault,formed during the Middle Jurassic Yanshanian orogeny,shows evidence of late Early Cretaceous left-lateral strike-slip motion,late Cretaceous normal faulting,and late Paleogene right-lateral strike-slip motion.Paleostress inversions indicate that southern Hubei Province experienced a series of paleostress fields,including a strike-slip stress field(with maximum principal stress oriented N-S and minimum principal stress oriented N-S)during the late Early Cretaceous,an NW-SE extensional stress field during the late Cretaceous,another strike-slip stress field(with maximum principal stress oriented NE-SW and minimum principal stress oriented N-S)during the early Paleogene,and a NE-SW extensional stress field during the late Paleogene.[Conclusion]Based on the polymetallic deposits in the study area,we conclude that secondary faults subparallel to the primary NE-SW trending fault,along with NW-SE and E-W trending faults intersecting with the primary NE-SW fault,present substantial potential for polymetallic mineral exploration.

关 键 词：幕阜山岩体 构造变形 古应力场 构造控矿作用 江南造山带 鄂南地区 

分 类 号：P612[天文地球—矿床学] P542[天文地球—地质学]