西藏下司马铁矿与华北典型铁矿的对比分析  

Comparative study of Xiasima iron deposit in Tibet and typical North China iron deposits

作　　者：高新宇 王登红[2] 黄凡[2] 王成辉[2] 李玉彬 李阳[4] GAO Xinyu;WANG Denghong;HUANG Fan;WANG Chenghui;LI Yubin;LI Yang(School of the Earth Sciences and Resources,China University of Geosciences(Beijing),Beijing 100083,China;Key Laboratory of Mineralization and Resource Evalutation Ministry of Natural Resources,Institute of Mineral Resources,Chinese Academy of Geological Sciences,Beijing 100037,China;College of Engineering,Tibet University,Tibet Lhasa 850000,China;Chengdu University of Technology,Sichuan Chengdu 610059,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]中国地质科学院矿产资源研究所自然资源部成矿作用与资源评价重点实验室,北京100037 [3]西藏大学工学院,西藏拉萨850000 [4]成都理工大学,地球科学学院,四川成都610059

出　　处：《中国地质调查》2023年第4期29-36,共8页Geological Survey of China

基　　金：中国地质调查局“中国矿产地质志(编号:DD20221695、DD20190379、DD20160346)”项目资助。

摘　　要：近年来华北沉积变质型铁矿的勘查工作取得了丰硕成果,但西藏此类矿床的勘查和研究程度较低。通过整理下司马铁矿的勘查资料,与5个华北典型铁矿的地质和地球化学特征进行对比研究,认为下司马铁矿属粒状铁建造(granular iron formation,GIF),成矿时代为中元古代(1.80~1.25 Ga),矿床成因可能是陆源风化和海底热液带来的Fe^(2+)在浅海大陆架氧化沉淀成矿,矿石整体较富集可能是原始沉积、岩浆热液的淋滤作用、区域变质作用等因素引起。下一步找矿工作应以高喜马拉雅成矿亚带的聂拉木岩群和亚东岩群为目标层位;重磁异常可作为重要的找矿标志,但应注意对局部低缓异常的解读;断裂和褶皱作用会影响矿体的最终定位,需注意辨别其性质。下司马铁矿和华北典型铁矿的对比研究可以为西藏地区沉积变质型铁矿的找矿提供参考。In recent years,great achievements have been made in the exploration of sedimentary metamorphic iron deposits in North China block.However,the exploration and research degree of such iron deposits in Tibet are relatively low.By sorting out the exploration data of Xiasima deposit and comparing it with five typical deposits in North China,the authors in this paper concluded that Xiasimaivon deposit belongs to granular iron formation(GIF),and the metallogenic age is Mesoproterozoic(1.80~1.25 Ga).The genesis of this deposit may be due to the oxidation and precipitation mineralization of ferrous iron in the shallow continental shelf caused by terri-genous weathering and submarine hydrothermal solution.The overall ore enrichment may be caused by the original sedimentation,leaching of magmatic hydrothermal solution,regional metamorphism and other factors.The next prospecting work should be focused on Nielamu Group and Yadong Group of the high Himalayan metallogenic sub belt,which are particularly important.Gravity and magnetic anomalies can be used as important prospecting indicators,but attentions should be paid to the interpretation of local low and slow anomalies.Fracture and folding will affect the final positioning of the ore body,and the identification of its properties should be appreciated.The comparative study of iron deposits in these two regions could also provide some references for the exploration of sedimentary metamorphic iron deposits in Tibet.

关 键 词：沉积变质型铁矿 矿床成因 找矿标志 西藏地区 华北陆块 

分 类 号：P624[天文地球—地质矿产勘探] P611[天文地球—地质学]