秦岭板块金矿床类型与金成色

秦岭板块内已发现五十多个金矿床(点),它们基本上赋存于志留、泥盆纪等沉积盆地中的容矿地层,受制于主造山期形成的成矿构造模型,可划分出细碎屑岩改造型、细碎屑岩-碳酸盐岩改造型、热水沉积改造型、火山-沉积改造型4种类型.矿床具层控特征,呈带状分布,形成于印支-燕山期.通过对区内典型金矿床金成色的对比研究,在空间上自北向南,除北部地区为中等金成色外,其余大部分地区为高成色;自东向西则呈波浪式变化.在时间上表现为随地层(层位)由老到新,总体呈逐步降低的趋势.在成矿深度及物质来源方面,则提供了该区中深度成矿、中深部物质来源的佐证.

Fineness of native gold and ore deposit type of gold deposits in Qinling tectonic plate

In Qinling tectonic plate, more than 50 gold deposits (points) have been found, and they are mainly hosted in the Silurian and Devonian stratum in the sedimentary basins, which controlled by metallotectonic belt formed in main orogenic period. These gold deposits types can be subdivided into four ones: microclastic rock type, microclastic-carbonate rock type, hydrothermal sedimentation type and volcanic sedimentation type. All deposits, formed in Indosinian-Yanshanian epoch, are stratabound and zonal distribution. By comparing study, the finenesses of gold in typical gold deposits from north to south are mainly high, except north area which is in middle. And, from west to east, fineness varies undulatingly. Generally, fineness of gold in the deposits in the more old strata tends to be more high, and vice versa. This study may also evidence that these deposits are mesogenic.