【作者】 杨建民； 毛景文； 王志良； 张作衡； 张招崇；

【Author】 Yang Jianmin Mao Jingwen Wang Zhiliang Zhang Zuoheng(Institute of Mineral Deposits, CAGS, Beijing)Zhang Zhaochong (Institute of Geology, CAGS, Beijing)

【机构】 中国地质科学院矿床地质研究所； 中国地质科学院地质研究所；

【摘要】 产于北祁连造山带中上元古界镜铁山群中的“镜铁山式”铁矿床因其规模巨大、成固独特而倍受关注,桦树沟铁矿床为其典型代表.镜铁山群为以陆源碎屑为主夹有白云质大理岩及铁矿层的浅海相沉积岩系,其中未发现肉眼可辨的火山岩或火山碎屑岩.铁矿体呈层状赋存于海相陆源碎屑沉积岩中,矿体的纹理和层理与容矿沉积岩的层理一致.铁矿石中矿物成分简单,金属矿物以镜铁矿、菱铁矿为主,脉石矿物以铁碧玉、白云石、方解石、重晶石为主.通过区域地质构造演化、岩石学、地球化学研究,表明“镜铁山式”铁矿床是产于大陆边缘坳陷槽(或“冒地槽”)内的以沉积岩为容岩的典型的Sedex型铁矿床,是一种新的铁矿类型.桦树沟铁矿成矿时代为中晚元古代更多还原

【Abstract】 The "Jingtieshan type" iron deposits, distributed in Middle and Upper Proterozoic Jingtieshan Group in the western part of North Qilianshan erogenic belt,have been paid close attention to their giant mineralization scale and unique genesis.The Huashugou iron deposit is a typical representative deposit.The Jingtieshan Group is mainly composed of shallow-sea sedimentary rock characterized by terrigenous clast which include dolomite-marble, but there can not be found the macroscopic volcanic rock or pyroclastic rock in them.The iron ore bodies occur as stratified in marine terrigenous clastic sedimentary rock.The lamination and stratification of orebodies is parellel with that of the host rocks.The component of iron ore is simple.The metallic minerals consist mainly of spacularite and siderite and the gangue minerals are mainly composed of iron-bearing jasperite and barite.According to the regional tectonics evolution, petrology and geochemistry,we conclude that the "Jingtie shan type"iron deposits is the typical"Sedex type" iron deposit--a new type of iron deposit which is occurred in depression flute ofcontinental margin(or miogeosyncline)and hosted in sedimentary rock.The Huashugou iron deposit is formed during Meso-and Neo-Proterozoic.更多还原