【作者】 李杰；

【导师】 申俊峰； 李金春；

【作者基本信息】 中国地质大学(北京) ， 地质工程， 2016， 硕士

【摘要】 甘肃省合作市岗岔-克莫金矿区位于秦岭造山带逆冲推覆构造北侧,北为岗岔金矿区,南为克莫28号金异常区。岗岔金矿床为甘肃甘南地区近几年新发现的受近南北断裂构造控制的中型浅成中低温热液矿床。本文以成因矿物学与找矿矿物学的理论和方法为基础,通过对矿床年代学、矿床地球化学特征、石英红外光谱、石英热释光、黄铁矿成因矿物学等几方面的研究,进一步为矿区深部矿化提供科学依据,指导深部找矿勘查。主要有以下几点认识:1.岗岔金矿区主要赋矿围岩安山岩为富Mg的钙碱性-偏铝质岩石,闪长岩为富Mg的钙碱性岩石-低钾岩石,闪长质“侵出相”岩石为富Mg的钙碱性-偏铝质岩石。这三类岩石均富集高场强元素(HFSE),亏损大离子亲石元素(LILE),轻稀土富集,重稀土亏损,铕呈弱负异常。2.岗岔金矿床主要赋矿围岩火山岩及侵入岩形成时代为242Ma-246Ma,成矿年龄为225Ma,前者的形成为后期成矿作用提供良好的成矿条件及成矿环境,侵入体为该矿区重要的找矿标志,对西秦岭北缘找矿具有重要意义。3.硫、铅同位素组成共同指示成矿物质来源与深部岩浆(壳幔混合来源)上侵有关,这类岩浆可能为下地壳拆沉形成的。氢、氧同位素指示成矿热液流体主要为岩浆水,并混少量大气降水,反映岗岔金矿床与岩浆活动关系较为密切。4.红外光谱测试结果表明,H2O的相对光密度值E1<2有利于成矿,CO2的相对光密值E2 0.3-0.5有利于成矿;D2/D1比值>0.2有利于成矿。该矿区大多数石英样品热释光呈现钝峰及无峰状态,表明该区受到了强烈的构造成矿作用。5.岗岔金矿床以亏硫型、低温元素(As+Sb)组合P型黄铁矿为主,矿床剥蚀度为25.5~38.5%,平均31.1%;黄铁矿形成温度范围为84.4~386.6℃,主要集中在200~280℃;黄铁矿中的ω(Fe)/ω(S+As)值集中分布在0.84-0.89之间,为浅成中低温矿床,推测Au3号矿脉第18-26勘探线、第2-5勘探线标高3000m以下,以及第5-23勘探线标高2800m以下可能具有良好的找矿前景。6.根据野外地质基础调查及室内实验分析推测,岗岔金矿区深部可能存在斑岩型矿床,深部找矿潜力较大。更多还原

【Abstract】 Gangcha-Kemo gold field of Hezuo in Gansu province is located in Qinling overthrust structure on the north side, north is Gangcha gold field, south is Kemo 28 sign gold abnormal place. Gangcha gold deposit is newly discovered medium shallow near the north and south by faults controlled epithermal deposits Gansu Gannan region in recent years.The essay is based on theories and methods of genesis minerageny and prospecting mineralogy, further provide scientific foundation of the mineralization of Gangcha gold deposit, and provide scientific basis for deep mine mineralization to guide deep prospecting by studying of deposit geochronology, geochemical and quartz infrared spectroscopy, quartz thermoluminescence light, pyrite genesis mineralogy.The main research results are as follows:1.The andesite of main host rock of Gangcha gold field is rock of alc-alkalinemetaluminous Mg-rich, diorite is rock of Mg-rich calc-alkaline-potassium, diorite "extrusive phase" rock is Mg-rich calc-alkaline-metaluminous. These three types rocks are enriched in high field strength elements, have a deficit LILE,enrich LREE, have weakly defict HREE, Eu negative anomaly feeble.2.The volcanic of main host rocks of Gangcha gold deposit and intrusive rocks take shape from 242Ma-246 Ma, age of mineralization is 225 Ma, the former post-mineralization provide good metallogenic conditions and metallogenic environment for after mineralize, intrusion is important symbol for prospecting and prospecting significance to western Qinglin.3.The composition of Sulfur and plumbum isotopic indicates a common source of magma minerals(crust-mantle mixed source) and related with the deep intrusion, this type magma may form the upper crust delamination. Isotope of Hydrogen and oxygen indicates mineralization of magmatic hydrothermal fluids mainly water and mixed with a small amount of precipitation, reflecting Gangcha gold deposit has closer relationship with magmatic activity.4.Test Results of infrared spectra indicate that, the relative optical density value E1 of H2 O <2 is favor of mineralization, the relative optical density values of E2 of CO2 range from 0.3-0.5 is favor of mineralization; D2/D1 proportionality >0.2 is favor of mineralization. Most quartz sample of mining area exhibits thermoluminescence peak and non-peak blunt state, indicate that the area has been strong tectonic mineralization.5.Gangcha gold deposit is based on sulfur deficiency type, low temperature elements combination of(As+Sb) P-type pyrite, deposit erosion of from 25.5 to 38.5%, an average of 31.1%; Pyrite formation temperature is range from 84.4 ~ 386.6℃, mainly concentrated in the 200 ~ 280℃; The ω(Fe)/ω(S+As) values of Pyrite concentrated in 0.84-0.89, as a hypabyssal epithermal deposit; presume below 3000 m of 18-26 and 2-5 exploration line and below 2800 m of 5-23 exploration line of No. Au3 veins might have good prospecting potential.6.Based on field analysis of Geological Survey and indoor experiments presume: There may be porphyry deposit in deep of Gangcha gold field, and deep prospecting potential for greater.更多还原