辽宁本溪大台沟铁矿地质特征及找矿标志

GEOLOGICAL CHARACTERISTICS AND PROSPECTING INDICATORS FOR DATAIGOU IRON DEPOSIT IN BENXI, LIAONING PROVINCE

辽宁本溪大台沟铁矿为鞍山-本溪铁矿成矿带内发现的首个位于标高-1000 m以下的特大型“鞍山式”铁矿床,含矿岩系为近直立展布的鞍山群樱桃园岩组,包含其内的铁矿体为隐伏的厚板状陡倾斜矿体,矿体埋深1100～1200 m,控制矿体延长2000 m.矿体自上向下可划分3种自然矿石类型,分别为赤铁矿石、赤铁磁铁复合矿石及磁铁矿石.大台沟铁矿床属典型“鞍山式”铁矿床,矿物成分较简单,含铁矿物以磁铁矿和赤铁矿（镜铁矿）为主;矿石结构类型有镶嵌粒状变晶结构、鳞片粒状变晶结构、柱状粒状变晶结构等;矿石构造类型以条带状为主.铁矿石TFe品位平均为29.34％;mFe品位平均为14.63％;矿石中其他元素含量除SiO2较高外,均甚微,SiO2平均含量46.08％.笔者在阐述大台沟铁矿地质特征基础上,总结出大台沟铁矿找矿标志,对于区域内潜在的“大台沟式”（埋藏较深、存在高大磁异常）铁矿床的找寻具有一定借鉴意义.

The Dataigou iron deposit in Benxi,Liaoning Province is the first oversize Anshan-type iron deposit explored below elevation of-1000 m in Anshan-Benxi iron ore metallogenic belt.The ore-bearing rock series are Yingtaoyuan Formation of Anshan Group,with concealed steeply dipping tabular iron orebody inside,buried in 1100-1200 m deep with extension of 2000 m long.The orebody falls into three natural ore types from top to bottom,i.e.hematite,hematite-magnetite complex and magnetite ores.The Dataigou iron deposit is of typical Anshan-type with simple mineral compositions,including iron-bearing minerals dominated by magnetite and hematite （specularite）.The iron ores are in mosaic,lepido and columnar granoblastic textures,with mainly banded structure.The average grade of TFe is 29.34％,with mFe of 14.63％,SiO2 of 46.08％ and little other elements.Based on the geological characteristics,the prospecting indicators of Dataigou iron deposit are summarized,which would provide reference for prospecting potential iron deposits with deep burial and significant magnetic anomaly in the region.