安徽省马鞍山市象塘铁矿地质特征及成因

Geological Characteristics and Genesis of Xiangtang Iron Deposit in Maanshan City,Anhui Province

马鞍山市象塘铁矿地处宁芜中生代火山岩盆地南段的南山铁矿东南边部,位于马鞍山市120°方向16km,距马鞍山市向山镇约8 km。结合矿区地质工作成果,详细分析了矿床地质特征、成因。研究表明:①象塘铁矿为典型的玢岩高-中温气液交代型铁矿床,属玢岩铁矿系列中的"陶村式"铁矿床,区内共发现铁矿体17条,主要赋存于辉石闪长玢岩体中;②矿石矿物主要为磁铁矿,次为假象赤铁矿、赤铁矿、褐铁矿等,少量镜铁矿、菱铁矿,矿石自然类型多为闪长玢岩浸染状磁铁矿石。在上述分析的基础上,进一步研究认为:①大王山旋回的辉石闪长(玢)岩为寻找玢岩铁矿的岩石标志;②断裂构造交叉部位、角砾构造体以及层带状冷缩裂隙带为寻找类"陶村式"铁矿的重要构造标志;③玢岩铁矿具有非常强烈的围岩蚀变及明显的蚀变分带,也为有利的找矿标志;④特征性的矿物脉体或团块是寻找深部及旁侧玢岩铁矿的重要线索;⑤磁异常、重力异常为寻找区内铁矿床的有利间接标志。

Xiangtang Iron Deposit in Maanshan City is located at the southeast margin of Nanshan Iron Deposit,which is distributed at the south section of Ningwu Mesozoic volcanic basin.Xiangtang Iron Deposit is located at 16 km to the 120°direction of Maanshan City,it is about 8 km away from Xiangshan Town in Maanshan City.Based on the related geological working results of the mining area,the deposit geological characteristics and genesis are studied.The study results show that:①Xiangtang Iron Deposit is a typical high-medium temperature gas-liquid metasomatism type porphyrite deposit,it belongs to"Taocun type"iron deposit in porphyrite series,a total of 17 iron orebodies are found in the mining area,they are mainly occurring in pyroxene diorite porphyrite rock mass;②the ore minerals are mainly for magnetite,followed by pseudomorphic hematite,hematite and lignite,and a small amount of specularite and siderite,most of the natural ores are diorite porphyrite disseminated magnetite ores.Based on the above discussion results,the further discussion results indicated that:①pyroxene diorite(porphyrite)rock mass of Dawagnshan cycle is the prospecting rock indicator for porphyrite iron deposit;②the intersecting position of fault structures,breccia structure and zonal shrinkage fracture zone are the important structural prospecting indicators for"Taocun type"iron deposit;③the surrounding rock alteration is strongly developed and the alteration zoning characteristics is obvious,which are the favorable prospecting indicators in the mining area;④the characteristic vein body or mass is an important clue to search for deep and lateral porphyrite iron deposit;⑤magnetic anomaly and gravity anomaly are the favorable indirect indicators for the exploration of iron deposits in the mining area.