黑龙江省老柞山金矿床地质、碳-氢-氧和硫-铅多元同位素特征及矿床成因探讨  

Discussion about geology,C-H-O and S-Pb multi-isotope characteristics,and genesis of Laozuoshan Gold Deposit in Heilongjiang Province

作　　者：耿瑞 李怡欣 张姗 孙景贵[3] 柏城璘 Geng Rui;Li Yixin;Zhang Shan;Sun Jinggui;Bai Chenglin(Mining Management Division,Shandong Gold Mining Co.,Ltd.;Shandong Gold Mining Co.,Ltd.;College of Earth Sciences,Jilin University)

机构地区：[1]山东黄金矿业股份有限公司矿业管理分公司 [2]山东黄金矿业股份有限公司 [3]吉林大学地球科学学院

出　　处：《黄金》2024年第10期25-31,共7页Gold

基　　金：国家自然科学基金项目(42072085)。

摘　　要：老柞山金矿床是中国东北地区的一座大型金矿床,产于兴蒙造山带东段佳木斯地块中部,是一个经历古亚洲洋、蒙古—鄂霍茨克洋、古太平洋俯冲叠加与转换的复合构造区。为了揭示成矿流体性质与组成,以及成矿物质来源,系统开展了成矿体系矿物流体包裹体的碳-氢-氧和矿石矿物硫-铅同位素研究。结果显示:δ^(13)C_(PDB)=3.932‰~5.390‰,δ^(18)O H_(2)O=2.17‰~5.60‰,δD=-90.569‰~-90.482‰,指示成矿流体主要来源于深部岩浆,成矿晚阶段伴随大气降水的混入,并与麻山群碳质岩系发生了一定程度的交换反应;矿体硫化物的δ^(34)S为3.3‰~5.1‰,矿化蚀变带硫化物的δ^(34)S为3.9‰~5.3‰,混合岩与花岗岩中硫化物的δ^(34)S为3.5‰~5.2‰,指示成矿流体性质为相对弱还原性;矿石矿物的^(206)Pb/^(204)Pb=18.165~18.571、^(207)Pb/^(204)Pb=15.452~15.613和^(208)Pb/^(204)Pb=37.764~38.396,岩浆岩的^(206)Pb/^(204)Pb=18.151~18.655、^(207)Pb/^(204)Pb=15.526~15.634、^(208)Pb/^(204)Pb=37.855~38.050。指示矿体和岩体具有同源性或成矿物质来自岩浆岩。根据与矿化密切相关的花岗闪长岩是下地壳部分熔融产物,可进一步推断成矿物质为壳源。结合矿床地质特征,认为老柞山金矿床为弱还原矽卡岩型金矿床。Laozuoshan Gold Deposit is a large-scale gold deposit located in Northeast China,within the central part of the Jiamusi Block in the eastern section of the Khingan-Mongolia orogenic belt.This area represents a complex tectonic zone,influenced by the subduction and transitions of the Paleo-Asian Ocean,the Mongolia-Okhotsk Ocean,and the Paleo-Pacific Ocean.To explore the nature and composition of the ore-forming fluids and the sources of metallogenic materials,systematic studies on C-H-O isotopes from ore-forming fluid inclusions and S-Pb isotopes from ore minerals were conducted.Results show thatδ^(13)C_(PDB)values range from 3.932‰to 5.390‰,δ^(18)O H_(2)O from^(2).17‰to 5.60‰,andδD from-90.482‰to-90.569‰,indicating that the ore-forming fluids are primarily derived from deep magmatic sources,with meteoric water mixing during the late mineralization stage and partial interaction with the carbonaceous rock units of the Mashan Group.Sulfides from the ore bodies haveδ^(34)S values ranging from 3.3‰to 5.1‰,sulfides from the mineralized alteration zones haveδ^(34)S values between 3.9‰and 5.3‰,and sulfides from the mixed rocks and granites range from 3.5‰to 5.2‰,suggesting that the ore-forming fluids were relatively weakly reducing.The Pb isotopic ratios of ore minerals are^(206)Pb/^(204)Pb=18.165-18.571,^(207)Pb/^(204)Pb=15.452-15.613,and^(208)Pb/^(204)Pb=37.764-38.396,while magmatic rocks have^(206)Pb/^(204)Pb=18.151-18.655,^(207)Pb/^(204)Pb=15.526-15.634,and^(208)Pb/^(204)Pb=37.855-38.050,indicating that the ore bodies and the magmatic rocks share a common origin,with ore-forming materials sourced from magmatic rocks.Given that the granodiorite closely associated with mineralization is the product of partial melting of the lower crust,it is further inferred that the ore-forming materials are crust-derived.Based on the geological characteristics of the deposit,it is concluded that Laozuoshan Gold Deposit is a weakly reducing skarn-type gold deposit.

关 键 词：老柞山 金矿床 矿床地质 碳-氢-氧和硫-铅同位素 矿床成因 佳木斯地块 矽卡岩型 

分 类 号：TD11[矿业工程—矿山地质测量] P618.51[天文地球—矿床学]