内蒙古白乃庙铜金矿区侵入岩锆石和磷灰石裂变径迹年代学及其地质意义  

Zircon and apatite fission track chronology of intrusive rocks in the Bainaimiao Cu-Au deposit,Inner Mongolia

作　　者：吕钊 许展[2] 庞建章[3] 王继春[2] 王建平[1] 袁硕浦 LU Zhao;XU Zhan;PANG Jianzhang;WANG Jichun;WANG Jianping;YUAN Shuopu(School of Earth Sciences and Resources,China University of Geosciences(Beijing),Beijing 100083,China;Geological Survey Institute of Inner Mongolia,Hohhot 010020,China;Institute of Geology,China Earthquake Administration,Beijing 100029,China)

机构地区：[1]中国地质大学(北京)地球科学与资源学院,北京100083 [2]内蒙古自治区地质调查院,内蒙古呼和浩特010020 [3]中国地震局地质研究所,北京100029

出　　处：《地学前缘》2023年第3期386-398,共13页Earth Science Frontiers

基　　金：内蒙古自治区地质勘查基金管理中心综合研究项目“中部满都拉白乃庙一带铜金多金属矿成矿规律与找矿预测(2018-01-YS01)”。

摘　　要：斑岩铜矿形成后常常遭受后期抬升剥蚀和破坏改造,内蒙古白乃庙铜金矿床是中国北方造山带中少有的几个早古生代斑岩铜矿床之一,其变化保存过程研究具有理论和找矿双重意义。锆石裂变径迹和磷灰石裂变径迹热年代学研究表明,自150 Ma以来白乃庙铜金矿区总体剥蚀量为3.11~3.25 km。矿区内岩体隆升冷却呈快速—缓慢—快速阶梯状3个阶段:150~<90 Ma快速剥露阶段,构造应力以挤压作用为主,平均剥蚀速率0.0457 mm/a;90~<20 Ma稳定剥蚀阶段,矿区构造应力由挤压转变为伸展,平均剥蚀速率0.0033 mm/a;20 Ma至今快速剥露阶段,矿区构造应力为挤压作用,平均剥蚀速率0.0388 mm/a。加里东期到燕山期,矿区受古亚洲洋俯冲、碰撞以及陆内造山活动的影响,白乃庙铜金矿成矿后处于挤压和伸展交替的环境,为白乃庙铜金矿的变化保存提供了有利的地质条件。Porphyry copper deposits often experience late-stage uplifting,denudation,destruction and transformation after deposition.The Bainaimiao Cu-Au deposit in Inner Mongolia is one of the few Early-Paleozoic porphyry copper deposits in the orogenic belt of northern China,therefore,it is of both theoretical and practical(in mineral prospecting)significance to study the mineral alteration/preservation processes.According to thermochronological analysis of zircon fission tracks and apatite fission tracks,the total denudation of the Cu-Au mining area since 150 Ma is between 3.113.25 km,and the late-stage uplifting and cooling of intrusive rocks in the study area can be characterized by a three-stage process.During the rapid exhumation stage between 15090 Ma,the tectonic stress is mainly compressional,and the average denudation rate is 0.0457 mm/a;in the stable denudation stage from 90 to 20 Ma,extensional stress dominates,and the average denudation rate is 0.0033 mm/a;and during the rapid exhumation stage from 20 Ma to present,compressional stress again dominates,and the average denudation rate is 0.0388 mm/a.Thus,from the Caledonian to Yanshanian,affected by subduction and collision of the ancient Asian Ocean and intracontinental orogenic activities,the mining area is under tectonic stresses alternating between compressional and extensional,which provides favorable geological conditions for mineral alteration/preservation in the Bainaimiao Cu-Au deposit.

关 键 词：白乃庙铜金矿 构造热历史 裂变径迹年龄 矿床变化保存 

分 类 号：P618.41[天文地球—矿床学]