西昆仑塔什库尔干地区磁铁矿矿床特征及其成因  

Geological Characteristics and Genesis of the Iron Deposits in the Taxkorgan Area, West Kunlun

作　　者：陈登辉[1] 伍跃中[1] 李文明[1] 王兴安[1] 乔耿彪[1] 赵晓健[1] 

机构地区：[1]中国地质调查局西安地质调查中心,陕西西安710054

出　　处：《大地构造与成矿学》2013年第4期671-684,共14页Geotectonica et Metallogenia

基　　金：中国地质调查局大调查项目(编号:12120113046200、1212011120541);“十二五国家科技支撑计划项目(编号:2011BAB06B00-02)”资助

摘　　要：塔什库尔干地区磁铁矿床位于西昆仑地区西部,目前发现了多个大中型磁铁矿床,截止2013年初控制资源量达10亿吨左右,是西昆仑地区近年来重大找矿突破之一,其发现具有重要的理论意义和勘探价值。塔什库尔干地区含矿地层主要为古元古界布伦阔勒岩群黑云母石英片岩和黑云斜长片麻岩。磁铁矿体呈层状或似层状,在区域上稳定产出。矿床中的金属矿物主要为磁铁矿和黄铁矿,非金属矿物主要为(硬)石膏、黑云母、绿泥石、石英。矿石以磁铁矿-石膏-黄铁矿组合为特征。矿石结构构造主要为浸染状构造、块状构造,保存有少量的条带状构造,自形-半自形粒状结构、它形粒状结构、交代假象结构等。塔什库尔干地区磁铁矿经历了原始沉积期、区域变质期、热液改造期和表生氧化期等四个成矿期;初步研究表明,大量的磁铁矿和(硬)石膏系原生沉积成因,大量的黄铁矿可能是后期热液与(硬)石膏作用的产物;研究区磁铁矿主要是与海底火山热液有关的沉积变质型铁矿,磁铁矿在原始沉积阶段有大量的陆源碎屑参与,与典型的BIF型铁矿有较大差异。The Taxkorgan area located in west of Kunlun and Arkin metallogenic belt, it hosts a few iron deposits with Fe reserves up to large scale, such as the Zankan, Mokaer, Laobing and Ylike iron deposits. The discovery of these deposits is one of the major breakthroughs in ore exploration in the area and of great academic significance. The main strata in the Taxkorgan district are biotite quartz schist and biotite plagioclase gneiss of Paleoproterozoic Bulunkuole Group. Magnetite ore bodies are layered or layer-like. The metallic minerals are magnetite and pyrite and the main gangue minerals are anhydrite （gypsum）, biotite, chlorite and quartz. The ores are characterized by magnetite- anhydrite-pyrite assemblage. The ore textures include euhedral-subhedral granular texture, anhedral granular texture, metasomatic pseudomorphic texture. The formation of the Taxkorgan iron deposits can be divided into four stages： initial sedimentary stage, regional metamorphic stage, hydrothermal transformation stage and supergene oxidation stage. The preliminary study showed that most of the magnetite and anhydrite （gypsum） formed in the initial sedimentary stage. Most of the pyrite may be the result ofpost-hydrothermal reaction with anhydrite （gypsum）. It can be concluded that the magnetite deposits in the Taxkorgan area were closely related to submarine volcanic hydrothermal sedimentary- metamorphic processes, however, there were a lot of terrigenous clastic participated in the forming processes, which is clearly different to the typical BIF type.

关 键 词：磁铁矿成因 矿床特征 布伦阔勒岩群 古元古界 塔什库尔干地区 

分 类 号：P611[天文地球—矿床学]