【作者】 李浩；

【导师】 杨永强；

【作者基本信息】 中国地质大学(北京) ， 矿产普查与勘探， 2016， 硕士

【摘要】 莲花山铜银矿床是位于大兴安岭中南段东坡的热液脉型铜银矿床。本文在详尽分析前人研究成果的基础之上,通过野外地质调查研究,深入分析了矿床地质特征、S、Pb同位素、黄铁矿单矿物的微量稀土元素、围岩的主量、微量元素特征,探讨了莲花山铜银矿床的岩石地球化学特征、成矿物质来源、成矿流体性质、岩体的形成年代,并建立了成矿模型,为下一步成矿预测与找矿方向提供理论依据,取得了以下成果和结论:（1）莲花山铜银矿成矿地质体为斜长二长花岗斑岩和中酸性火山—次火山岩,其中,斜长二长花岗斑岩是源于亏损地幔,并且在侵位过程中受到了地壳或岩石圈地幔混染作用的钙碱性I型花岗岩,形成于华北板块和西伯利亚板块碰撞后（即古亚洲洋闭合后）的岩石圈伸展环境。（2）莲花山铜银矿赋矿围岩为偏基性的闪长玢岩,其源于俯冲洋/陆壳析出流体交代地幔楔或亏损地幔的减压部分熔融作用,而中酸性岩则是其结晶分异作用的产物,其形成于古亚洲洋闭合过程中的洋陆俯冲造山或造山后阶段,与岩石圈伸展减薄和软流圈上涌作用相关。（3）莲花山铜银矿床金属硫化物硫同位素组成变化范围较小,δ³⁴S_V-CDT的值主要介于0.0‰³.5‰之间,其塔式分布特点明显,指示该矿床成矿流体中硫的来源主要为深部岩浆;铅同位素的研究结果表明:成矿物质主要来源于发生壳幔物质混合的岩浆,并受到造山作用的影响。（4）莲花山铜银矿床黄铁矿单矿物的稀土元素和微量元素特征表明:成矿流体具有富集LREE、亏损HFSE,Hf/Sm、Nb/La和Th/La比值小于1的特征,推断莲花山铜银矿床的成矿流体为富Cl流体而非富F流体;其与矿区内中酸性火山—次火山岩的相似性显示,莲花山铜银矿床的成矿物质主要来源于中酸性火山—次火山岩,并在一定程度上萃取了围岩的成分。（5）黄铁矿的Zr-Hf、Nb-Ta、Y-Ho比值显示,莲花山铜银矿床的成矿热液受到了后期火山热液活动的干扰,而黄铁矿的Co/Ni比值表明,莲花山铜银矿床为火山热液成因矿床。更多还原

【Abstract】 The Lianhuashan Ag-Cu deposit is a hydrothermal vien-type deposit located at the east along middle-south segment of Da Hinggan Mountains.Based on a detailed analysis of predecessor research results and field geological survey,this paper has deep analysis of the deposits geological feature,S-Pb isotope,trace elements of pyrite and the main trace elements of surrounding rock,we explored the geochemical characteristics of rock,source of ore-forming materials,ore-forming fluid characteristics and the rock mass formation age about the Lianhuashan Ag-Cu deposit,established the mineralization model,provided theoretical basis for the future metallogenic prediction and prospecting direction,the main results and conclusions obtained were as follows:1)The ore-forming geological body of Lianhuashan Ag-Cu deposit are plagioclase granite porphyry and intermediate-acid volcanic subvolcanic rocks.The plagioclase granite porphyry are Ca-alkaline I-typed granite,originating from the depleted mantle,and in the process of emplacement affected by the earth’s crust or lithosphere mantle contamination;Its formed from lithosphere extension environment after the closure of north China plate and Siberia plate.2)The diorite porphyrite of Lianhuashan Ag-Cu deposit origination from a metasomatized mantle wedge or depleted mantle,which had been modified during the previous subcontinental/oceanic subduction.The intermediate-acid rocks were derived from the differentiated crystallization of basaltic magmas.They are formed in ocean-land subduction orogenic or post-tectonic stage during the closure of Old Asian Ocean,relating to the extension of lithosphere resulting from the up-welling of asthenosphere.3)Theδ³⁴S_VCDT of metal sulfides from the Lianhuashan Ag-Cu deposit vary from 0.0‰to3.0‰,varying in a narrow range and have obvious characteristics of tower-type distribution,which implies that the sulfur was mainly derived from the deep-seated magma.The results of lead isotopes suggesting that the lead of the ore is mainly derived from mixture of crust-mantle materials and affected by the orogeny.4)REE composition and trace element characteristics of pyrite in the Lianhuashan Ag-Cu deposit show that:ore forming fluid strong enrichment in LREE,depleted high field strength element（HFSE）and its Hf/Sm,Th/La,Nb/La ratios are almostly less than 1,infeing that the ore forming fluid of Lianhuashan Ag-Cu deposit is mainly originated from the Cl rich mineralization hydrothermal.They are similarity to the intermediate-acid volcanic subvolcanic rocks in the mining area show that ore-forming materials mainly comes from intermediate-acid volcanic subvolcanic rocks,and extracting the composition from surrounding rock in a certain extent.5)The Zr-Hf,Nb-Ta,Y-Ho ratios indicated that ore-forming hydrothermal in the Lianhuashan Ag-Cu deposit has affected by the late volcanic hydrothermal activity.The Co/Ni elemental ratios suggested that the Lianhuashan Ag-Cu deposit is volcanic hydrothermal origin.更多还原