摘要
陕西略阳东沟坝矿床地处“摩天岭地块”东部硖口驿-黑木林中—新元古代基底拼合带北侧,是与晋宁期碧口岛弧海相火山岩相关的金-银-铅-锌多金属中型矿床。笔者较系统地梳理了矿床地质特征,综合矿床最新勘查成果和前人科研资料,在深入坑道考察和开展硫同位素测试分析的基础上,进行了矿床的成矿期次划分、成矿物质来源、矿床成因分析等方面的成矿规律研究。结果表明:①矿床产于新元古代碧口岩群岛弧火山岩中,具多期矿化叠加特征;成矿期次主要包括3个阶段:石英-黄铁矿-闪锌矿初始预富集成矿阶段;金-银-重晶石主要成矿阶段;重晶石-碳酸盐晚期成矿阶段。②矿(岩)石硫同位素具有δ^(34)S重晶石>δ^(34)S黄铁矿>δ^(34)S闪锌矿>δ^(34)S方铅矿特征,证明矿床形成时硫同位素分馏已基本达到平衡;硫同位素δ^(34)S V-CDT值普遍具花岗质岩浆硫特征,仅有少量处于幔源硫区间,表明东沟坝矿床硫可能主要来源于下地壳岩浆源,仅有少量的地幔物质混入;而其成矿物质可能主要来自于晋宁期岛弧火山岩浆作用。③东沟坝矿床为晋宁期海相含矿中酸性火山岩浆热液在多次构造作用叠加形成的矿床,属于典型的火山块状硫化物型(VMS)金银铅锌多金属矿床。④矿床形成于晋宁期活动陆缘背景下,隶属中元古代—新元古代古陆块裂解-汇聚成矿地质事件;推测矿床的成岩、成矿过程可能与晋宁期古扬子东、西部微板块俯冲汇聚、后续构造叠加延续有关。
The Donggouba depost is located at north margin of Xiakouyi-Heimulin Meso-Neoproterozoic basement structure zone,east of the Motianling block.It is a special Au-Ag-Pb-Zn polymetallic medium deposit related to the Marine volcanic rocks of Bikou island arc in the Jinning Period.By integrating the latest progress on the exploration and previous scientific research data,we systematically summarized the geological characteristics of deposit,investigated the pits,analyzed the sulfur isotope of the ores and,finally,studied the metallogenic regularity of the deposit in terms of the classification of metallogenic periods,tracing the metallogenic materials and the genetic analysis of the deposits.The main results are as follows:①the deposit is located within the Neoproterozoic volcanic arc rocks of Bikou Group,and is characterized by multi-stage mineralization superimposition.The mineralization process mainly include three stages:quartz-pyrite-sphalerite initial pre-enrichment mineralization stage;gold-silver-barite main mineralization stage;barite-carbonate late mineralization stage.②the sulfur isotope(δ^(34)S)of minerals show an order of barite>pyrite>sphalerite>galena,which suggests that the sulfur isotope fractionation had basically reached equilibrium when the deposit was formed.Theδ^(34)S V-CDT values of the Donggouba deposit generally display the characteristics of granitic sulfur with a small quantity of mantle-derived sulfur,indicating that the sulfur in Donggouba deposit may be dominantly derived from the lower crust magma source with minor mantle material.The sources of the ores may come from the volcanic magmatism of the Jinning island arc.③Donggouba deposit is formed by the polyphase tectonic superimposition of ore-bearing hydrothermal fluids derived from Marine intermediate-acid volcanic rocks in the Jinning period.It is a typical volcanic massive sulfide(VMS)type gold,silver,lead and zinc polymetallic deposit.④the deposit formed on the active continental margin in Jinning Period,and belongs to the
作者
王长春
袁攀
吴新斌
王东
陈剑祥
崔建军
WANG Changchun;YUAN Pan;WU Xinbin;WANG Dong;CHEN Jianxiang;CUI Jianjun(Shaanxi Geological and Hanzhong Geological Brigade Co.,Ltd.,Hanzhong 723000,Shaanxi,China;Chinese Academy of Geological Sciences,Beijing 100081,China)
出处
《西北地质》
CAS
CSCD
北大核心
2022年第4期300-315,共16页
Northwestern Geology
基金
陕西地矿汉中地质大队地质科研专项资金项目(HZKY202101)资助。
关键词
东沟坝多金属矿床
地质特征
成矿规律
硫同位素
陕西略阳
Donggouba polymetallic deposit
geologic feature
genesis of deposit
sulfur isotope
Lueyang,Shaanxi province
