【作者】 杨利亚；

【导师】 杨立强；

【作者基本信息】 中国地质大学（北京） ， 矿物学、岩石学、矿床学， 2014， 博士

【摘要】 阳山金矿带位于西秦岭勉略缝合带的文县弧形构造带内，是研究复合造山带中金矿成因的理想选区，巨量金的来源及聚集机理是亟需深入研究的关键科学问题。论文通过系统的矿床地质和多元同位素示踪研究，获得如下主要成果。（1）通过矿相学研究将阳山金矿带的时间演化划分为3期5个阶段，分别为：沉积-成岩期、成矿期早阶段、成矿期主阶段、成矿期晚阶段和成矿后。（2）C-H-O同位素研究表明，阳山金矿带成矿流体主要为变质水，混有部分岩浆水和少量的大气降水。在成矿期早阶段流体以岩浆水为主，形成演化的岩浆水；成矿主阶段则主要为变质水运移过程中不断与泥盆纪地层发生水岩作用，形成演化的变质水；晚阶段成矿流体主要为变质水和岩浆水形成的混合流体，并有大气降水的加入；成矿后，流体中大量大气降水的加入，使其氢、氧同位素组成明显向大气降水线漂移。（3）S-Pb同位素研究表明，阳山金矿带成矿物质与碧口群关系不明显，主要来源于泥盆纪地层，少量来源于中酸性岩脉。沉积-成岩期黄铁矿具有典型沉积硫特征，变化范围比较宽；成矿期早阶段黄铁矿硫为2.84~3.24，岩浆源特征；成矿期主阶段硫同位素组成为7.63~10.93与泥盆系地层硫同位素组成（10.1‰和10.9‰）相一致，成矿期晚阶段硫同位素组成为5.81~7.91，具有与成矿主阶段类似的硫同位素组成特征，表征阳山金矿带硫主要来源于泥盆系地层。不同赋矿围岩及不同成矿阶段硫化物Pb同位素组成进一步证实了成矿物质主要来源于泥盆纪地层。（4）通过统计分析前人锆石U-Pb测年、独居石U-Th-Pb电子探测年和K-Ar测年得出，阳山成矿带主要成岩与成矿年龄相近，约为185Ma。（5）通过查明阳山金矿带成矿流体和成矿物质来源、成矿时代，结合其基础地质研究，分别与卡林-类卡林金矿、造山型金矿进行综合对比，得出阳山金矿带为造山型金矿。更多还原

【Abstract】 The Yangshan gold deposit belt is located in Wenxian arc structural belt, whichbelongs to the Mian-Lue suture of the West Qinling orogeny tectonically. Therefore,this gold deposit belt is believed to be an ideal region for exploring the genesis of golddeposits developed in composite orogenenic belts. The key scientific problemsinclude the source of vast quantity of gold and the mechanism for its accumulation.We conducted detailed field work on this gold ore belt, and collected samplessystematically for multi-isotope determination and further tracing the sources ofore-forming fluid and materials. Below are the main conclusions we have in thisstudy:(1) Based on ore microscopic observations, we divide the evolution of this golddeposit belt into3phases and5stages, including depositional-diagenetic phase, earlystage in ore-forming phase, main stage in ore-forming phase, late stage in ore-forming,and post ore-forming phase.(2) Analysis for C-H-O isotopic data indicates that the ore-forming fluid of thisdeposit belt mainly consists of metamorphic water mixing with minor magmatic andmeteoric water. In the early stage of the ore-forming phase, the fluid is dominated byevolved magmatic water; in the main stage, the ore-forming fluid is evolvedmetamorphic water formed via water-rock reaction between metamorphic water andthe surrounding Devonian strata during fluid migration; the ore-forming fluid for thelate stage is a mixture of metamorphic and magmatic water with some addition ofmeteoric water, while abundant meteoric water was added into the fluid in postore-forming phase, as evidenced by the migration of H-O isotopic composition towardmeteoric water line in the plot.(3) S-Pb isotopic data for pyrites show the ore-forming materials of this golddeposit belt are mainly derived from those Devonian strata and with minor frommedium-acidic dikes, but appear to have no obvious relationship with the Bikougroup. For the depositional-diagenetic phase, those pyrites yield typically sedimentarysulfur with a broad range of values. The sulfur data for the early stage of the ore-forming phase varies at2.84-3.24‰, which is indicative of magmatic source. Thesulfur isotopic values for the main stage are from7.63‰to10.93‰, which isconsistent with those of the Devonian strata (10.1‰and10.9‰). Also, the sulfurisotopic data in the late stage are similar to those of the main stage, varying at5.81~7.91‰. These two together imply those Devonian strata provide the ore-formingmaterials, which is further confirmed by Pb isotopic data from various kinds ofwall-rock and sulfide minerals at different stages of the ore-forming phase.(4) Based on integrated zircon U-Pb dating, monazite U-Th-Pb dating, and K-Ardating, it is revealed that the main metallogenetic timing is close to the maindiagenetic timing, both around185Ma.(5) The Yangshan gold deposit belt iscompared with Carlin-type and orogenicgold deposits in terms of geological conditions and sources of the ore-forming fluidand materials constrained by multiple isotope analysis, and is ascribed to be orogenicgold deposits.更多还原