几种不同类型金矿的高精度磁测异常特征

High-precision magnetical anomaly characteristics of different gold deposit types

许多金矿的赋矿(或伴生)岩石与其周围岩石之间存在着磁性差异,如与中基性脉岩有关的金矿成因模式矿床、破碎蚀变火山岩型金矿等,在其上能观测到磁异常。即使是河床底部缝隙中与砂金相伴沉淀的重砂,由于铁磁性矿物含量较高,与其附近砂石之间存在磁性差异,利用高精度质子磁力仪,也能观测到比较明显的磁异常。在西藏自治区及四川省一些金矿床(点)上的研究取得了良好的进展,对砂金矿、锑金伴生型金矿,中基性脉岩型金矿上的高精度磁测异常特征有了新的认识,为利用高精度磁测方法间接寻找金矿积累了经验。

Magnetism difference exists between the gold-bearing rock and its wall rocks in many gold (deposits). For example, magnetic anomalies have been measured on the gold deposits yielded in meso-basic dyke rocks and crash altered volcanic rocks. Because the magnetism of the heavy sands nearby the gold placer is stronger than that of the other sands, the magnetic anomalies also can be measured by using high-precision proton magnetometer. Great progress has been made in the research on some gold deposits in Sichuan Province and Tibet. New ideas about the characteristics of high-precision magnetical anomalies of gold placer and gold deposits yielded in meso-basic dyke rocks must be useful to explore indirectly the gold deposits with high-precision magnetic survey.