高精度磁测在IOCG型铁矿勘查中的应用--以智利英格瓦塞铁矿为例

The application of high-precision magnetic survey to exploration of IOCG type iron deposits: Exemplified by the Incaguasi iron deposit in Chile

IOCG型(铁氧化物铜金型)矿床富含铁氧化物,且常缺失硫化物,高精度磁测是寻找IOCG矿床重要的有效手段之一。英格瓦塞铁矿位于智利中北部IOCG型矿床成矿带,前期地质工作程度较低。在智利英格瓦塞铁矿矿区地质特征调查基础上,重点针对中部矿区的7个磁异常区,利用RGIS对其高精度磁测数据进行面积上延、面积下延、剖面下延及2.5D反演拟合处理,结果表明,本区引起磁异常的磁性地质体整体呈NE向延伸、倾向NW、倾角较陡。除Ⅰ号和Ⅴ号磁异常规模较小外,其他几个磁异常中心找矿前景较大,有规模的磁异常区大多埋深在50~120 m之间,为下一步地质找矿钻探验证提供了有效的基础。同时,该勘查方法可为中国IOCG型铁矿找矿工作提供参考依据。

The IOCG type deposits are rich in iron oxides and often lacks sulfide, the high precision magnetic survey seems to bethe important and effective meansin search for this type of deposits.The Incaguasi iron deposit is located in the IOCG metallogenic belt of north-central Chile and its geological work remains at relatively low level.Based on geological characteristics of this deposit, this paper focuses on upward continuation, downward continuation and 2.5D inversion fitting for the high precision magnetic data of the central mining area by RGIS.The results show that the magnetic geological body in this area is generally NE-striking and NW-dipping with steep dip angle.Expect for No.1 and No.5 anomaly, several magnetic anomaly centers for ore prospecting are relatively large and the burial depths are generally between 50 m and 120 m.These results provide an effective basis for the further geological prospecting.At the same time, this exploration method can provide reference for the prospecting work of IOCG type iron ore deposits in China.