塞拉利昂北方省Gpafaya铁矿地质特征及成因浅析

塞拉利昂北方省Gpafaya铁矿位于西非塞拉利昂中东部的克拉通内,产出于太古宙绿岩带内,处于苏拉山—坎格瑞丘陵弧形构造带北北西向转折部位。该区成矿条件优越,以盛产金、铁而闻名。矿体主要赋存在磁铁云母石英片岩中;矿石呈细粒、微细粒变晶结构,条带状构造;矿物组分简单,主要原生矿石矿物为磁铁矿。研究表明,Gpafaya铁矿为阿尔戈马BIF型铁矿,缺乏强烈的构造变形和大规模的流体活动可能是该区难以形成富铁矿的主要原因,局部的富矿体可能形成于原始沉积。磁铁石英片岩、高磁异常及正地形可作为Gpafaya铁矿主要的找矿标志。

Geological characteristics and genesis of Gpafaya iron deposit in the north province, Sierra Leone

The Gpafaya iron deposit is located in the eastern craton of western Sierra Leone. The deposit occurs in the Archean greenstone belt and turning part of NNW-trending Sula mountains-Kangari Hills arc structure belt. The metallogenic condition of the area is superior, and the area is well known for its gold and iron resources. Orebodies are mainly distributed in magnetite mica quartz schist. Ore has fine grained texture and banded structure. Ore mineral is simple, mainly primary ore mineral is magnetite. The Gpafaya iron deposit is Algoma type BIF. Lacking of intensive structural deformation and fluid activities maybe are the main reason for high grade iron deposit could not been formed, local high grade orebody may be formed in the primary sedimentary stage.The magnetite quartz schists, high magnetic anomalies, and positive landforms are prospecting indicators of the Gpafaya iron deposit.