中蒙边境阿尔山地区铁多金属矿成因类型、成矿地质条件及找矿方向

阿尔山地区位于中蒙边境南蒙古—东乌旗—阿尔山铁多金属成矿带上，具有巨大的找矿潜力。但由于该区为大兴安岭森林覆盖区且地质勘查程度低，长期以来找矿一直未取得较大进展。结合1∶5万矿调工作成果，将区内铁多金属矿按成因类型划分为3类，对经济价值巨大的矽卡岩型、沉积变质型铁多金属矿进行了重点分析，并与蒙古国南蒙古、我国内蒙古东乌旗地区的典型矿床进行了对比研究。结果表明：南蒙古—东乌旗—阿尔山铁多金属成矿带矽卡岩型铁多金属矿床主要受NE向大断裂及其派生的次一级断裂控制，矽卡岩都为与酸性岩浆岩有关的钙矽卡岩，容矿围岩都含有利于矽卡岩矿床成矿的碳酸盐岩石，围岩蚀变主要为矽卡岩化、硅化、碳酸盐化、绿帘石化等；该铁多金属成矿带沉积变质型铁多金属矿床主要受NE向褶皱控制，都为与大规模燕山早期酸性侵入岩有关的BIF型铁矿，都具有原始海相沉积后期变质叠加改造成矿的特点，都为低品位矿石，主要容矿围岩都为板岩、片岩、千枚岩等中低级变质岩。在此基础上，初步总结了阿尔山地区铁多金属矿的成矿地质条件与找矿方向，并划分出不同成因矿床的成矿远景区。随着地质勘探工作的进一步加强，该区有望发现大型矽卡岩型铁多金属矿、大中型沉积变质型铁多金属矿及中小型热液脉型铁多金属矿。

Genetic Types,Metallogenic Geological Conditions and Prospecting Directions of Fe-polymetallic Deposits in Aershan Area of China-Mongolia Border

Aershan area is located on Fe-polymetallic mineralization belt of southern Mongolia-Dong Ujimqin Banner-Aershanon China-Mongolia border，which prospecting potential is huge.However，due to the low level of geological exploration and the forested area of Great Khingan， the prospecting has not made great progress for a long time.Combined with the 1∶50 000 ore survey working results of the area，the polymetallic iron deposits in the area is divided into three types according to their genetic types. The skarn type and sedimentary metamorphic type iron polymetallic deposits with great economic value are emphatically analyzed，besides that，the comparative study with the typical ore deposits in Southern Mongolia and Dongwuqi Area of Inner Mongolia， China is done.The results show that:The skarn type iron polymetallic deposits in the Southern Mongolia-East Wuqi-Aershan iron polymetallic metallogenic belt are mainly controlled by the NE-trending faults and their derived sub-faults，skarn is calcium skarn related to acid magmatic rocks，the ore-bearing surrounding rock contains carbonate rock which is conducive to the mineralization of skarn deposit，the surrounding rock alteration mainly includes skarn， silication， carbonation and epidotization.The sedimentary metamorphic iron polymetallic deposits in the iron polymetallic metallogenic belt are mainly controlled by NE-trending folds，all of them are BIF type iron ores related to large scale early Yanshanian acid intrusive rocks，all of them have the characteristics of metamorphic superimposed transformation of mineralization in the later stage of primitive Marine deposition，all of them are low grade ores， and the main host rocks are middle and low grade metamorphic rocks such as SLATE， schist and phyllite.On this basis， the metallogenic geological conditions and prospecting direction of iron polymetallic deposits in the Arshan area are preliminarily summarized， and the metallogenic prospective areas of different genetic deposits are divided.With the further strengthening of geological exploration，it is expected to find large skarn type iron polymetallic ore， large and medium-sized sedimentary metamorphic iron polymetallic ore and small and medium-sized hydrothermal vein type iron polymetallic ore in the area.