黑龙江省三合屯金矿床深部电性结构与成矿模式  

Deep Electrical Structure and Metallogenic Model in Sanhetun Mining Area,Heilongjiang Province

作　　者：高科宁 邓居智 刘文玉[1,2] 余辉 陈辉 周聪[1,2] 王彦国 刘宝山[3] Gao Kening;Deng Juzhi;Liu Wenyu;Yu Hui;Chen Hui;Zhou Cong;Wang Yanguo;Liu Baoshan(School of Geophysics and Measurement-Control Technology,East China University of Technology,Nanchang 330013,China;State Key Laboratory of Nuclear Resources and Environment(East China University of Technology),Nanchang 330013,China;Shenyang Geological Survey Center,China Geological Survey,Shenyang 110034,China)

机构地区：[1]东华理工大学地球物理与测控技术学院,南昌330013 [2]核资源与环境国家重点实验室(东华理工大学),南昌330013 [3]中国地质调查局沈阳地质调查中心,沈阳110034

出　　处：《吉林大学学报（地球科学版）》2022年第3期684-700,共17页Journal of Jilin University：Earth Science Edition

基　　金：国家自然科学基金项目(41864004,41674077);中国地质调查局项目(DD201901564);江西省主要学科学术带头人(青年)培养计划(20204BCJL23058);东华理工大学研究生创新基金(DHYC 202014)。

摘　　要：黑龙江省三合屯金矿床位于嫩江—黑河构造混杂岩带西南端,地表第四系覆盖层较厚且深部地球物理工作程度不足,制约了该地区深部找矿的突破和对成矿模式的认识.本文采用非线性共轭梯度法对横跨该矿床的音频大地电磁长剖面(约8.5km)数据进行二维反演,获得了研究区二维精细电性结构.结果表明:三合屯金矿床地区100m以浅呈现低阻异常特征,反映了该地区浅层为白垩系砂泥岩和第四系风化物;剖面西北侧连续分布的低阻层与下伏高阻异常区分别指示了白垩纪火山岩和石炭纪侵入岩;剖面下方的高低阻转换带揭示了韧性剪切带和断裂等导矿和储矿构造的深部展布特征.结合区域地质资料,本文建立了三合屯金矿床成矿模式:在早—中侏罗世伸展构造背景下,成矿流体沿着断裂、韧性剪切带向上运移,并将晚石炭世侵入岩中的金元素淋滤浸出,促成了研究区第一期成矿;早白垩世研究区再次处于伸展拉分背景下,深部岩浆喷发所携带的金元素随岩浆热液沿着新形成以及重新活化的韧性剪切带和盆缘断裂向三合屯火山盆地边缘运移,后期随着温度的下降逐渐沉淀富集,并叠加在早期形成的矿化之上.The Sanhetun gold deposit in Heilongjiang Province is located at the southwest end of the Nenjiang-Heihe tectonic melangite gold metallogenic belt.Due to the thick Quaternary overburden and insufficient deep geophysical work,the breakthrough of the deep prospecting and the research of metallogenic model are restricted.In this study,the two-dimensional electrical structure of the study area was obtained by the two-dimensional data inversion of the audio geomagnetic long profile(about 8.5 km)across the deposit using the nonlinear conjugate gradient method.The results show that the 100 m shallow layer of the Sanhetun gold deposit has the characteristics of low resistivity.It reflects the shallow Cretaceous sand-mudstone and Quaternary weathering in this area.The continuous distribution of low resistance layers and the underlying high resistance anomalies in the northwest side of the section indicates the Cretaceous volcanic rocks and Carboniferous intrusive rocks.The high and low resistance transition zones under the section reveal the deep distribution characteristics of ductile shear zones and faults.These are important ore guiding and storage structures.In this paper,the metallogenic model of the Sanhetun gold deposit is established based on the regional geological data.In the Early-Middle Jurassic tectonic extensional period,the ore-forming fluid migrated upward along the fault and ductile shear zone,and then leached the gold elements from the Late Carboniferous intrusive rocks,which contributed to the first phase of mineralization in the study area.In the Early Cretaceous,the study area was again in an extensional and pull-apart setting,and the gold elements carried by the deep magmatic eruptions were transported along the newly formed and reactivated ductile shear zones and basin margin fractures toward the edge of the Sanhetun volcanic basin with the magmatic hydrothermal fluids,and gradually precipitated and superimposed on the top of the earlier mineralization phase with the temperature decrease in the late

关 键 词：三合屯金矿床 音频大地电磁测深 电性结构 成矿模式 火山热液型金矿床 

分 类 号：P618.51[天文地球—矿床学] P631[天文地球—地质学]