塞拉利昂北方省MALUMPO铁矿NHC-4矿段地质特征及找矿标志

Geological Characteristics and Prospecting Criteria of NHC-4 Section of Malumpo Iron Deposit in the North Provine of Sierra Leone

MALUMPO铁矿位于塞拉利昂中东部的苏拉山-坎格瑞丘陵(Sula Mountain-Kangari Hill)弧形构造带转折部位,产于太古宇绿岩带内,为沉积变质铁矿床(BIF型)。NHC-4矿段主矿体规模大,呈层状、似层状,具有分支复合、膨大收缩现象,与围岩整合接触,采用平行断面法进行资源量估算,探获(332+333)铁矿石资源量上亿吨。文章通过分析成矿地质条件,认为该类矿床的磁异常具有一定的规律性,精度磁测所获得的正负异常交替处是寻找磁铁矿的有利部位,太古宇坎布伊岩群为主要找矿目标层。

The MALUMPO iron deposit is located in the curved tectonic belt of Sula Mountain-Kangari Hill in the Middle East of Sierra leone.It is located in the Archean greenbelt and is a sedimentary metamorphic iron deposit(BIF type).The main orebody in NHC-4 section is a large,layered and stratified oreboday which appeared as the compound of branches and shrinkage from expansion and contacting with the surrounding rocks.The parallel section method is adopted to estimate the resources and resulted in over 100 million ton iron ore(332+333)in the deposit.This paper,through analysis of metallogenic geological conditions,concludes that there is a certain regularity on the magnetic anomalies of this type of deposits and the alteration of the positive and negative anomalies obtaind from precision magnetic survey is the favorable position to find the magnetite deposit.Therefore,the Kanbuyiyan formation in the study area is the main prospecting targets.