凤县八卦庙特大型金矿热水沉积岩的地质地球化学特征

八卦庙特大型金矿的成因引人注目 ,作者提出含矿地层中存在的一套条带状岩石属于热水沉积成因。此套岩石顺层产出 ,主要由富石英纹层、富钠长石 -石英纹层和富铁碳酸盐纹层互层 ,构成纹层条带构造 ,具有沉积韵律和沉积旋回 ;地层走向上 ,条带状岩石渐变过渡为千枚岩或板岩 ,显示局部凹陷的热水沉积盆地特点 ;条带岩的化学成分、微量元素特征与秦岭泥盆系铅锌矿床中的硅质 -钠质 -铁碳酸质热水沉积岩非常相似 ,具有热水沉积特点。热水沉积岩与金矿化空间关系密切 ,说明八卦庙金矿属于热水沉积 (改造 )型金矿床。矿床成因类型的正确认识有利于指导区域找矿工作。

Geological and Geochemical Characteristics of the Hydrothermal Sediments in the Baguamiao Gold Deposit

The genesis of the Baguamiao gold deposit is noticeable. The author suggests that the banded rocks in the ore beds are of hydrothermal origin. This series of rocks occur along the strata, consisting mainly of interbeds of quartz-rich laminae, albite-quartz laminae and iron-rich carbonate laminae, which form a banded structure with sedimentary rhythms and sedimentary cycles. The banded rocks have gradually changed into phyllite or slate, which show characteristics of a hydrothermal sediment basin locally depressed. The chemical composition and microelement characteristics of the banded rocks are similar to those of siliceous, sodic and iron-carbonaceous hydrothermal sedimentary rocks in the Devonian lead-zinc deposits in the Qinling region. The hydrothermal sedimentary rocks are closely related to gold mineralization in space, which indicates that the Baguamiao gold deposit belongs to the hot water sedimentation (transformation) type. A correct understanding of the genetic type of the deposit is most helpful for ore prospecting in the region.