摘要
大水金矿围岩蚀变强烈,且具有多阶段性,蚀变类型主要有硅化、赤铁矿化、碳酸盐化等。本文通过对大水金矿床中碳酸盐矿物地球化学特征、稳定同位素特征及磁铁矿与赤铁矿间转化关系研究,结合等浓度图法等方法,对矿床的围岩蚀变与金的成矿关系进行了探讨。结果表明:矿床中各阶段方解石的碳质均来自中三叠统马热松多组(T_(2)m)碳酸盐地层的去碳酸盐化作用;赤铁矿化是在非氧化还原模式下,由于磁铁矿中Fe^(2+)被淋滤带出而形成的。结论认为:大水金矿床并非形成于氧化环境,去碳酸盐化—硅化+金矿化—方解石化是连续—完整的蚀变矿化过程,去碳酸盐化及赤铁矿化增加了围岩的孔隙度和渗透率,加速了成矿流体的运移与水岩反应速率;金矿化与硅化、赤铁矿化关系密切。
The wall rock alteration of Dashui gold deposit is intense and multi-stage.The main alteration types are silicification,hematite mineralization,and carbonation.Based on the geochemical characteristics of carbonate minerals in the Dashui gold deposit,the transformation relationship between magnetite and hematite,and the isoconcentration mapping method are used to discuss the relationship between wall rock alteration and mineralization of the deposit.It turned out that:the C of calcite in each stage of the deposit comes from the carbonatite of Middle Triassic Marresongduo Formation(T_(2)m);the hematite is a kind of altered product,which is formed in the non-redox mode by the leaching of Fe^(2+)from magnetite.The results suggested that:the Dashui gold deposit is not formed in an oxidizing environment,and the decarbonization-silicification+Au mineralization-calcite is a continuous and complete alteration-mineralization process.Porosity and permeability of the surrounding rock increased by decarbonization and hematitization,as a result,the migration of ore-forming fluids and the rate of water-rock reaction also improved;gold mineralization is closely related to magmatic activity.
作者
南银仓
王滔
毛艳丽
李林积
黄从俊
NAN Yin-cang;WANG Tao;MAO Yan-li;LI Lin-ji;HUANG Cong-jun(The Third Institute of Geology and Mineral Exploration,Gansu Provincial Bureau of Geology and Mineral Exploration and Development,Lanzhou 730050,China;Chengdu Center of China Geological Survey,Chengdu 610081,China;Technology Innovation Center for Gold Exploration and Utilization of Gansu Province,Lanzhou 730050,China)
出处
《甘肃地质》
2024年第1期17-25,共9页
Gansu Geology
基金
甘肃省玛曲县大水金矿接替资源勘查(项目编号:1212011220727)。
