陕西省铧厂沟金矿围岩蚀变和元素迁移特征  

Wall-rock alteration and element migration of the Huachanggou Gold Deposit,Shaanxi Province

作　　者：林振文[1,2] 秦艳[1] 岳素伟[3] 周振菊[4] 王立新 余康伟 

机构地区：[1]中国科学院广州地球化学研究所矿物学与成矿学重点实验室,广东广州510640 [2]中国科学院大学,北京100049 [3]华南理工大学广州学院,广东广州510800 [4]北京大学造山带与地壳演化教育部重点实验室,北京100871 [5]陕西省略阳县铧厂沟金矿,陕西略阳724312

出　　处：《地球化学》2014年第6期602-618,共17页Geochimica

基　　金：国家自然科学基金(40730421,40425006);全国危机矿山接替资源找矿项目(20089934)

摘　　要：陕西省铧厂沟金矿床位于勉略缝合带以南,矿体受控于近东西向逆冲断层和韧脆性剪切带。本文以细碧岩矿带为例,系统研究了围岩蚀变分带及蚀变矿物组合,总结了矿床的蚀变分带模式。围岩蚀变以穿切细碧岩透镜体的剪切带为中心向外依次可划分为黄铁绢英岩化带、绢云碳酸盐化带和绿泥赤铁矿化带。蚀变矿物组合分别为黄铁矿+铁白云石+铬云母+绢云母+钠长石+石英+方解石、铁白云石+绢云母+钠长石+石英±黄铁矿、(铁)绿泥石+钠长石+铁白云石+赤铁矿+钛铁氧化物+石英±绿帘石。蚀变岩石组分迁移分析表明,在围岩蚀变过程中,Si O2、Na2O、Fe2O3T、Mg O与Y等组分发生不同程度的迁出,K2O、Ca O、Ba、Rb、Sr、Cr、Cu、Pb和挥发组分等迁入,并以黄铁绢英岩化带最为显著。金在成矿流体中以Au(HS)–2络合物迁移,成矿流体与富铁细碧岩之间的反应是金沉淀重要机制。The Huachanggou gold deposit in Shaanxi province is located to the south of Mianlue suture zone. The ore bodies are mainly controlled by EW trending reverse faults and ductile-brittle shear zones. Based on detailed study of alteration mineral association in the main ore zone that hosted in the spilite tectonic lens, an alteration zoning model has been established. The wall rock alteration can be divided into three alteration zones outward from the shear center： pyrite - phyllic alteration zone, sericite - carbonate alteration zone, chlorite - hematite alteration zone. The alteration mineral associations are pyrite ＋ ankerite ＋ fuchsite ＋ sericite ＋ albite ＋ quartz ＋calcite, ankerite＋sericite＋albite＋quartz ± pyrite, and chlorite＋albite＋ankerite＋hematite＋ilmenite oxide＋quartz ± epidote, respectively. The elements migration analysis showed that SiO2, Na2O, Fe2O3T, MgO and Y occur to move out in varying degrees, while K2O, CaO, Ba, Rb, Sr, Cr, Cu, Pb and volatile components move in during alteration. The most intensive migration occurred in the pyrite phyllic alteration zone. Gold is mainly transported as Au（HS）–2 complex in the hydrothermal fluids. It seems that fluid-rock interaction between ore-forming fluid and Fe-rich spilite plays an important role in gold precipitation.

关 键 词：造山型金矿 蚀变分带 元素迁移 铧厂沟金矿 陕西省 

分 类 号：P595[天文地球—地球化学] P618.51[天文地球—地质学]