河南罗山金城金矿床成矿物质来源探讨  

Discussion on Material Sources of Jincheng Gold Deposit, Luoshan County,Henan Province

作　　者：刘洪[1,2] 吕新彪[2,3] 尚世超[2] 王玉奇[2,4] 李春诚[2] 刘阁[2,5] 杨永胜[3] 胡二红[2,4] 黄基汉[2,5] 

机构地区：[1]中国地质调查局成都地质矿产研究所,四川成都610081 [2]中国地质大学资源学院,湖北武汉430074 [3]中国地质大学地质调查研究院,湖北武汉430074 [4]内蒙古地质矿产勘查开发局第八地质矿产勘查开发院,内蒙古乌海016000 [5]新疆维吾尔自治区地质矿产勘查开发局,新疆乌鲁木齐830011

出　　处：《现代地质》2013年第4期869-878,共10页Geoscience

基　　金：中国有色金属工业协会鑫达金银开发中心项目"河南罗山鑫恒金矿找矿综合研究与成矿预测"

摘　　要：河南省金城金矿床位于桐柏—商城韧性剪切带南部、大别山西北侧。矿床赋存于中元古界苏家河群浒湾岩组变质岩中。在详细分析金城金矿床地质特征的基础上,研究共生花岗斑岩脉的微量元素、稀土元素地球化学特征,共生石英的氧同位素、共生石英流体包裹体中CO2的碳同位素及共生黄铁矿的硫、铅同位素组成特征,并与老湾金矿和燕山晚期灵山花岗岩体对比。研究发现,本区花岗斑岩脉的稀土配分曲线和微量元素蛛网图与灵山花岗岩体几乎完全重叠,稀土元素和微量元素特征参数较为一致,结合区域资料推断本区与矿体共生的花岗斑岩脉来源于燕山晚期岩浆活动。黄铁矿δ34S值变化范围为-6.9‰～5.5‰,均值为2.3‰,与区域上地层和岩浆岩硫同位素对比,认为金城矿床载金黄铁矿的硫主要来源于浒湾岩组围岩。载金黄铁矿铅同位素和浒湾岩组地层铅同位素范围相当,均有下地壳铅源的特征,结合硫同位素分析,认为金城金矿床载金黄铁矿的铅主要来源于浒湾岩组围岩。δ18OSMOW变化范围为5.5‰～11.4‰,极差为5.9‰,均值为8.4‰,具有岩浆热液石英的特征;δ18CPDB变化范围为-6.3‰～-2.8‰,极差为3.5‰,均值为-4.4‰,具有岩浆源或深部源碳(-7‰)和沉积碳酸盐岩来源碳(0)混合的特征;综合研究表明,本矿床成矿物质主要来源于浒湾岩组含金岩石建造,部分来源于燕山晚期岩浆热液活动。The Jincheng gold deposit,in the Luoshan County,Henan Province,lies in south of TongbaiShangcheng ductile shear zone. The ore deposit,which occurs in the east side of Lingshan granitic mass,is hosted in the lower stratum of Huwan formation complex in the upper Proterozoic. Based on the geologic feature, we conducted the comparative study on REE and trace element characteristics of granite-porphyry dyke and Lingshan granitic mass,moreover we further investigated the oxygen isotope compositions of the paragenous quartz and the carbon isotope compositions of fluid inclusions within paragenous quartz,as well as the sulfur and lead isotope compositions of the paragenous pyrite. We found that the REE and trace element characteristics of granite-porphyry dyke is similar to those of the Lingshan granitic mass,and that the granite-porphyry dyke originated in the magmatic hydrothermal activities in the late Yanshanian stage. The δ34 S value of pyrite in the main orebody ranges from 6. 9‰ to ＋ 5. 5‰ with a mean of ＋ 2. 3‰. The lead isotope composition show the typical characteristics of the lower crust lead isotope,similar to those of Huwan formation complex. The δ18 O values in the ore range from ＋ 5. 5‰ to ＋ 11. 4‰ with a mean of ＋ 2. 3‰; the δ13 CCO 2PDB values of fluid inclusions within paragenous quartz range from ＋ 6. 3‰ to ＋ 2. 8‰ with a mean of ＋ 4. 4‰. The δ18 O-δ13 C results suggest that ore fluids mainly came from magmatic hydrothermal fluids with participation of small amounts of atmospheric water. According to our research,we consider that the ore-forming materials are mainly derived from the Huwan formation complex,and secondly derived from the magmatic hydrothermal activities in the late Yanshanian stage.

关 键 词：桐柏—大别 金城金矿 稀土元素 微量元素 同位素 河南罗山 

分 类 号：P618.5[天文地球—矿床学]