摘要
随着紫金山金铜矿露天采矿规模的不断扩大,许多与矿床成因密切相关的地质现象被剥露出来,露采场成为进行矿床地质研究的最佳场所。本文对紫金山金铜矿露采场的构造、矿化及蚀变分带特征进行了详细研究,研究表明:在自北向南靠近火山机构的过程中,蚀变带依次为绢云母+地开石化带、地开石+明矾石化带、地开石+褐铁矿化带和强硅化带,各个蚀变带内的主要金属矿物组合变化依次为黄铁矿+斑铜矿±硫砷铜矿±蓝辉铜矿,黄铁矿+蓝辉铜矿+铜蓝+硫砷铜矿±斑铜矿,褐铁矿+针铁矿+自然金+次生铜蓝+孔雀石,黄铁矿+斑铜矿+硫砷铜矿+蓝辉铜矿。在空间分布上,主要的矿石矿物在水平方向上从斑铜矿渐变为蓝辉铜矿,垂直方向上从上部的自然金+褐铁矿向下变为蓝辉铜矿+斑铜矿,深部变为铜蓝±蓝辉铜矿。蚀变分带与金属矿物组合的空间分布都体现出在靠近火山机构及深度增加的过程中成矿热液的硫逸度和氧逸度越来越高。矿石中还出现了具有指示意义的含锡矿物。这些特征都表明紫金山金铜矿是含矿热液多期次叠加的结果。金的富集成矿和金铜的矿化分带受北西向与北东向密集节理交汇带的控制。
With the expansion of the open-pit of Zijinshan Au-Cu deposit, many geological features closely related to the genesis of deposit have been exposed. The fault structures, mineralization and alteration zones of the Zijinshan Mine have been investigated. It suggests that adjacent to a volcanic pipe and from north to south and, alteration zones vary from a sericite+dickite alteration zone to a dickite+alunite alteration zone, then to a dickite+limonite zone and a silicified zone. The major mineral assemblages within each alteration zones are respectively: pyrite, bornite, enargite and digenite; pyrite, digenite, covellite, bornite and enargite; limonite, goethite and native gold; and, pyrite, bornite, enargite and digenite. The spatial distribution of mineral assemblages in the horizontal direction contain major copper minerals varying from bornite-dominated to digenite-dominated ore. Vertically, the mineral assemblages change from the native gold and limonite in the upper levels changing to bornite and digenite and to covellite at lower levels. Accordingly, these characteristics of mineral distribution are controlled by fault fractures and the volcanic pipe. Both the alteration zoning and spatial distribution of mineral assemblages indicate, adjacent to the volcanic pipe, the sulfur fugacity and oxygen fugacity are increasing with hydrothermal mineralisation. Small amounts of tin-bearing minerals with indicating significance also occur in the ore. Above all, the geological features suggest that Zijinshan Au-Cu deposit is the result of a multi-stage hydrothermal superimposition. The enrichment of gold and the boundary between gold and copper deposits is controlled by the intersection of the north-east fracture zones and north-west fracture zones.
出处
《矿物学报》
CAS
CSCD
北大核心
2015年第2期167-177,共11页
Acta Mineralogica Sinica
基金
福建省自然科学基金(2012J01170
2011J01270)
国家自然科学基金(批准号:41002016)
关键词
紫金山金铜矿
蚀变分带
断裂构造
矿物组合
硫逸度
Zijinshan Au-Cu deposit
alteration zone
fault structure
mineral assemblage
sulphur fugacity
