安徽蒙城西贾庄金铅锌多金属矿床成矿物质来源探讨  

On the sources of the ore-forming materials of the Xijiazhuang gold-leadzinc polymetallic deposit in Mengcheng,Anhui

作　　者：李斌[1] 黄寄洲 李仁和[2] 陈广涛[2] 张赞赞[1] LI Bin;HUANG Jizhou;LI Renhe;CHEN Guangtao;ZHANG Zanzan(Geological Survey of Anhui Province(Institute of Geological Sciences of Anhui Province),Hefei,Anhui 230001,China;Institute of Geophysical and Geochemical Survey Technology of Anhui Province,Hefei,Anhui 23001,China)

机构地区：[1]安徽省地质调查院(安徽省地质科学研究所),安徽合肥230001 [2]安徽省地球物理地球化学勘查技术院,安徽合肥230001

出　　处：《安徽地质》2024年第4期289-295,共7页Geology of Anhui

基　　金：安徽省公益性地质调查项目“1∶5万楚店集、高炉集、江集和望町集覆盖区综合地质调查”(编号:2016-g-3-32)资助。

摘　　要：西贾庄金铅锌多金属矿床位于华北克拉通东南缘,中国东部郯庐断裂带西侧,是近年来在皖西北地区新发现的多金属矿床,也是在皖西北深覆盖区找矿的突破。本文在其矿床地质特征和碳、氧、硫、铅同位素地球化学研究结果的基础上,探讨了该矿床成矿流体和成矿物质来源。研究结果:主要脉石矿物热液方解石δ^(13)CV-PDB值为-3.8‰~-5.5‰,平均值为-4.7‰;δ^(18)OV-SMOW值为11.9‰~14.2‰,平均值为13.0‰,表明成矿流体主要来自深部岩浆热液,广泛发育的水岩反应导致有海相碳酸盐岩的碳、氧加入;矿石矿物黄铁矿、方铅矿、闪锌矿硫同位素组成表现为δ^(34)S黄铁矿>δ^(34)S闪锌矿>δ^(34)S方铅矿,表明硫同位素分馏基本达到平衡;δ^(34)S值为3.7‰~6.0‰,平均值为5.2‰,指示成矿物质来自岩浆,并有部分地层物质加入;矿石矿物黄铁矿、方铅矿的^(206)Pb/^(204)Pb值为16.742~16.787,^(207)Pb/^(204)Pb值为15.333~15.399,^(208)Pb/^(204)Pb值为37.298~37.482,所有数据落在下地壳和造山带之间或下地壳区域,认为矿石铅主要来源于下地壳和地幔,具有壳幔混合源特征。The Xijiazhuang gold-lead-zinc polymetallic deposit is located in the southeastern margin of the North China Craton,in the western part of the Tan-Lu Fault Zone in eastern China.It is a newly discovered polymetallic deposit as a breakthrough in mineral exploration in the thick overburden area in northwestern Anhui.Based on the geological characteristics of the deposit and the geochemical survey results of carbon,oxygen,sulfur and lead isotopes,this paper discusses the sources of ore-forming fluids and materials,indicating that the δ^(13)CV-PDB value of hydrothermal calcite,the predominant gangue mineral,spans from -3.8‰ to -5.5‰,averaging -4.7‰,while the δ^(18)OV-SMOW value ranges between 11.9‰ and 14.2‰,averaging 13.0‰,which suggest that the ore-forming fluid originates mainly from deep magmatic hydrothermal solution,with significant water-rock interactions contributing to the incorporation of carbon and oxygen from marine carbonate rocks.The sulfur isotopic composition of ore minerals pyrite,galena,and sphalerite shows δ^(34)Spyrite>δ^(34)Ssphalerite>δ^(34) Sgalena,indicating that sulfur isotopic fractionation has basically reached equilibrium;the δ^(34)S value ranges from 3.7‰ to 6.0‰,with an average of 5.2‰,indicating that the mineralizing material comes from magma and partially from strata.The ore minerals of pyrite and galena have values of ^(206)Pb/^(204)Pb ranging from 16.742 to 16.787,^(207)Pb/^(204)Pb from 15.333 to 15.399,and ^(208)Pb/^(204)Pb from 37.298 to 37.482,all of which lie in the domain between the lower crust and orogenic belt,or in that of lower crust,indicating that lead in the ore comes mostly from the lower crust and mantle,with the characteristics of the two combined.

关 键 词：金铅锌 碳、氧同位素 硫同位素 铅同位素 成矿物质来源 西贾庄 蚌埠隆起 

分 类 号：P611[天文地球—矿床学]