金山店铁矿地质地球化学特征

Geological and geochemical characteristics of Jinshandian iron deposit

金山店铁矿是鄂东南地区典型的矽卡岩型矿之一,除具有明显的热液交代特征外,还具有矿浆贯入特征。因此,本文对金山店铁矿稠密浸染状矿石、具有冷凝边的块状矿石、石英闪长岩、灰岩进行了研究。ICP-MS分析结果表明,虽然两类矿石亲铁、亲硫元素差异并不明显,但在稀土元素的配分模式和微量元素分布上表现出了明显的差异。稠密浸染状矿石具有与灰岩类似的分布特征,而具冷凝边的块状矿石具有与石英闪长岩相似的特征。这表明两类矿石虽然具有共同的成矿物质来源,但具有不同的成因。通过与本区矿浆型铁矿矿石对比,得知金山店具有冷凝边的块状矿石并非矿浆成因,但与石英闪长岩具有密切的成因联系,推测其成矿流体可能是一种矿浆-热液过渡型流体,为具有一定温度、粘度、含有一定挥发分的富铁流体。

Jinshandian iron deposit is one o{ the typical skarn-type deposits in the southeastern area of Hubei Province,with ore-pulp filling characteristics, besides with the hydrothermal metasomatic features. Therefore, this article has studied of dense disseminated ores,massive ore with the condensing boundary,quartz diorite and limestone in Jinshandian Fe deposit. ICP-MS analysis result shows that there is not an obvious difference between the siderophile elements and sulfophilie elements of two type ores, but there is an obvious difference in REE distribution patterns and trace element distribution between them. Dense disseminated ores and limestone have the similar distribution characteristics, and the ore with condensing boundary has the similar feature of quartz diorite. It is suggested that the two types of ore are derived from the common sources of ore-forming materials, but with different genesis. Compared with ore-pulp-type iron ore in this ar ca,it is indicated that the ore with condensing boundary is not of ore-pulp genesis, but it has a close genesis relationship with the quartz diorite. It is proposed that the metallogenic fluid might be a kind of transitional fluid between ore pulp and hydrothermal fluid, for the iron-rich fluid of a certain temperature, viscosity containing some volatile composition.