西昆仑铁克里克构造带康开铁矿床地质特征及成因

Ore Geological Characteristics and Genesis of Kangkai Iron Deposit in Tiekelik Tectonic Belt of West Kunlun,China

康开铁矿床位于西昆仑铁克里克构造带中段北缘,赋矿地层为元古代喀拉喀什岩群和埃连卡特岩群变质岩,发育镜铁矿和磁铁矿两种铁矿化类型。镜铁矿体受断层构造控制,呈脉状、似层状、团块状和细脉状产出。磁铁矿化体包括磁铁石英岩型和基性岩型,其中磁铁石英岩型矿石具有沉积变质型特征,基性岩型矿石表现为基性岩内发育浸染状磁铁矿和少量黄铜矿。依据两种铁矿化类型的矿物组合、结构构造、围岩蚀变和不同类型矿化体的时空关系等特征,将其成矿作用过程划分为沉积期、变质期、岩浆期和构造热液期4个成矿期,即该矿床是多期复合成矿作用的产物。沉积期和变质期形成的磁铁石英岩中的磁铁矿和岩浆期形成的基性岩中的磁铁矿为后期构造热液期发育的镜铁矿体提供了成矿元素来源,因此,出露于地表(浅部)的镜铁矿体可作为寻找周围和深部与磁铁石英岩和基性岩有关的磁铁矿的找矿标志,这一标志在铁克里克构造带中可能具有普遍性意义。

Kangkai iron deposit is located in the northern margin of the middle section of Tiekelik tectonic belt, West Kunlun,China.There are two types of iron mineralization including specularite and magnetite,which develop within the metamorphic rocks of Proterozoic Kalakashi Group and Ailiankate Group.The specularite mineralized body is controlled by fault structures,occurring as vein,stratoid,massive and veinlet.The magnetite mineralized body occurs both in the itabirite and the basic rock,the former is resulted from sedimentary-metamorphic process,and the latter is shown as disseminated magnetite and minor chalcopyrite developed within the basic rock.In terms of the characteristics of mineral assemblage and paragenetic association,ore texture and structure,wall rock alteration,and crosscutting relationship of different types of mineralized body,the mineralization of Kangkai iron deposit is divided into sedimentary,metamorphic,magmatic,and tectonic hydrothermal periods,namely this deposit is the product of multi-period superposed mineralization.The specularite formed during tectonic hydrothermal period is derived from the magnetite formed during sedimentary-metamorphic and magmatic periods,consequently the specularite occurred in shallow ground can be used as a kind of prospecting criteria for the exploration of magnetite related to the itabirite and basic rock at depth and surrounding area,and this prospecting criteria could be applicable to the whole Tiekelike tectonic belt.