金的自然富集作用

• 作 者: W.S.Fyfe R.Kerrich 黄德华 蒋永年
• 出 处: 国外前寒武纪地质
• 发表日期: 1985年04期
• 关键词: 非均质 石英脉 碳酸盐沉积 安山岩 孔隙流体 富集作用 围岩蚀变 地热梯度 流体控制 丰度值

引言构成地壳的原生岩是火成的,并以玄武岩,安山岩-流纹岩套及其相当的深成岩石为主。人们逐渐认为,玄武岩来自上升对流块体所在地的非均质地幔,而安山岩-花岗岩套包含在具有程度不同的地壳混染作用的下降块体中。对玄武岩、安山岩及超镁铁质岩来说,金的正常背景浓度在2ppb 范围内(表1)。

INTRODUCTION The primary rocks that make up the crust are igneous and are dominated by basalt, andesite-rhyolite sets and their equivalent deep-formed rocks. It has come to be assumed that basalt comes from a heterogeneous mantle where the uplifting blocks are located, while andesite-granite casings are contained in downdrafts with varying levels of crustal contamination. For basalt, andesite, and ultramafite, the normal background gold concentration is in the 2 ppb range (Table 1).