中国低温热液矿床集中分布区的一些地质特点

通过对我国西南地区低温热液矿床集中分布区的区域地质背景（包括基底、盖层、构造与地球物理特征）和一些低温热液矿床的地质特征的研究,重点对低温热液矿床集中分布在中国西南地区的条件进行了初步探讨。提出：（１）巨厚的地壳使温度高的地幔对容矿地层的面型影响不强烈,只是在一些切壳的深大断裂附近形成一些较高的地温场、小岩体和岩脉;（２）区内元古代基底区域变质作用不强,经受的温度、压力都不是很高,致使元古界岩石中的成矿元素没有大量被结晶（变质）分异作用排出,因而其成矿元素丰度较高;（３）新元古代—古生代巨厚的沉积盖层显示出该区长时间、大面积稳定下沉,岩浆活动（特别是侵入活动）不强烈;（４）盖层中大量含碳质细碎屑岩与碳酸盐岩石相间出现的岩性组合反映了海进海退、氧化还原的沉积环境变化,有利于成矿元素沉淀富集;（５）很多低温热液矿床成矿物质都来自深部,因此巨厚的盖层有利于成矿过程中缓慢降温而形成大量的低温热液矿床     

福建紫金山矿田火成岩系列与浅成低温热液—斑岩铜金银成矿系统

紫金山矿田内, 自地表往深部, 发育早白垩世中酸性火山岩、次火山英安斑岩、浅成相花岗闪长斑岩、中深成相花岗闪长岩, 构成中酸性火山-侵入岩系列。围绕着紫金山火山机构发育强烈的蚀变矿化, 形成高硫型浅成低温热液铜金矿、低硫型浅成低温热液银金矿和斑岩型铜(钼)矿床。矿田内各类铜金银矿床存在着密切的时空及物源联系, 它们在时间、空间上连续演化, 都是同源含矿中酸性岩浆在同一成矿背景之下于不同演化阶段的产物。含矿热液的物化性质及时空迁移决定了它们在不同地质部位产出不同的矿床类型, 构成与中酸性次火山-斑岩有关的浅成低温-斑岩铜金银矿成矿系统。      

胶莱盆地地质解译及金矿床地质--地球物理-地球化学背景

从出露基底找金走向隐伏基底找金的新思路出发，对胶莱盆地内的地层、构造、岩浆岩运用物—化探信息和深钻资料给予深刻明晰的解译，发现其与胶北隆起区有着相似的地、物、化背景条件。指出胶莱盆地是座落在太古—元古宙基底之上的中新生代盆地，具有基底与盖层的双层结构，它们分别形成金矿的矿源层和衍生矿源层，展示了胶莱盆地的找矿前景。结合矿化信息以及典型矿床实例的地、物、化特点的解剖，指出矿化规律和控矿因素，建立了矿床地质一地球物理一地球化学找矿模型，并圈定了1：20万预测靶区以及靶区中可能出现的主要矿床类型，为进一步勘查工作指出了方向。     

西藏自治区谢通门县斯弄多铅锌矿区地球物理特征及找矿方向

浅成低温热液型矿床是一类主要产于陆相火山岩或与陆相火山岩有关的低温热液矿床,矿床埋藏深度浅是其最大的特点,这也使地球物理勘探方法在这类矿床的勘查中具有先天优势。本文通过对西藏斯弄多Pb-Zn-Ag多金属浅成低温热液型矿床的地球物理参数特征研究,采用激发极化法等综合物探技术在矿体外围探获具有巨大前景的Pb-Zn-Au-Ag浅成低温热液型矿体。目前单工程控制有3段矿体:顶部Au-Ag矿体,中部Au矿体,底部Pb-Zn-Ag矿体。矿体最高Au品位可达5.3g/t,Ag最高品位410g/t,Pb+Zn综合平均品位5.9%。研究结果表明,斯弄多地区林子宗群火山岩物性参数稳定,对矿体异常干扰较小,产于该套火山岩中极强硅化体中的浅成低温热液型Au矿多具有中高极化率和中低阻特征。     

中国浅成低温热液金矿床

浅成低温热液金矿床在中国传统上称为陆相火山岩型金矿床,主要发现在中国东部,后来在北疆地区也有新的发现.根据产出的大地构造背景,它们集中分布在3个带,并分属于3个成矿时期.它们包括:(1)新生代台湾东部岛弧带;(2)晚古生代北疆岛弧带;(3)中生代沿中朝克拉通北界的大陆边缘带;(4)中生代中国东南沿海地区的大陆边缘带.绝大多数矿床是低硫化型的,只有3个是高硫化型的,另有1个是与碱性岩系有关的Au-Te型矿床.除了中国最大的金矿床金瓜石矿床外,迄今为止中国大陆上的浅成低温热液金矿床总的来说只有较小的经济重要性.在中国东部发现的浅成低温热液金矿床的总储量,与区内广泛分布的中生代陆相火山岩十分巨大的体积极不相称.较古老的成矿年龄,中国东部的中生代和北疆的晚古生代,是中国大陆浅成低温热液金矿床的一个鲜明的特点.根据中国的成矿条件和保存条件的分析,以及与美国西部和俄国东部的对比,提出了中国浅成低温热液金矿床成矿潜力的一个初步评估.北疆可能有较大的寻找浅成低温热液金矿床的潜在重要性.     

Epithermal deposits in North Xinjiang, NW China

The North Xinjiang region (NW China) is an important part of the Central Asia Orogenic Belt, situated at the junction of Siberia, Tarim and Kazakhstan plates. It is an area characterized by multiple stages of Phanerozoic continental growth, during which several porphyry and epithermal systems were formed. The relationship of these mineral systems to the geodynamic evolution of the region has not yet been well understood. In this paper, we list the main geological characteristics of 21 significant epithermal precious and base metal deposits in North Xinjiang, and classify them into high-sulfidation and low-sulfidation styles, with the latter being predominant. We have selected seven epithermal deposits representing different styles formed under different tectonic regimes and discuss their geology and geochemistry in some detail. The deposit-scale geology and geochemistry of epithermal systems in North Xinjiang are essentially similar to those in other parts of the world. All epithermal deposits in North Xinjiang are hosted in volcanic rocks with ages ranging from Devonian to Triassic, with the Early Carboniferous volcanic sequences being the most important, followed by the Permian and Triassic. The Devonian–Early Carboniferous host rocks belong to the calc-alkaline series that developed in pre-collisional arc-back-arc basin systems; whereas the Permian–Triassic host volcanic rocks of shoshonite series formed in post-subduction regimes. Available isotopic ages of these epithermal systems cluster in two periods: Early Carboniferous (>320?Ma) and Late Carboniferous–Triassic (320–220?Ma), reflecting two metallogenic episodes that occurred during subduction-related accretion and post-subduction collision regimes, respectively. Accordingly, three groups of epithermal deposits in North Xinjiang can be recognized as (1) pre-collisional deposits without or with negligible collisional-related modification, (2) deposits formed in collision regime and (3) ore systems strongly overprinted by fluid flow in post-subduction collision regime.     

浅成低温热液型金矿特点、分布和找矿前景

浅成低温热液矿床的概念,最初由Lindgren首先提出.20世纪80年代以来环太平洋活动带上一系列大型、超大型金矿床的发现,在世界范围内掀起了一股空前的"浅成低温金矿"热.浅成低温金矿具有低温、低压、低盐度、成矿深度浅的特点.矿化作用发生在火山活动晚期,最终定位于火山地热系统波及范围内.全球浅成低温金矿明显呈集中成带分布的特点,绝大多数分布在著名的环太平洋带、古特提斯带和中亚-蒙古(古亚洲)带.此类金矿成矿在时间上的分布特点大体是①第三纪(最重要)、②第四纪更新世(次重要)、③中生代(重要)、④石炭-二叠纪(次要).成矿环境主要为岛弧带、板内走滑断裂带和上叠火山盆地、陆内裂谷.我国地处三大浅成低温成矿带分布区,已经发现诸如阿希、团结沟、紫金山等金(铜)矿床,找寻同类矿产前景广阔.     

伊朗浅成低温热液矿床时空分布规律与矿床类型

特提斯成矿域是地球上三大成矿域之一,矿产资源丰富.文章综述了特提斯域内伊朗高原浅成低温热液矿床的地质特征,讨论了成矿事件的时空分布规律以及主要矿床类型.研究表明,伊朗浅成低温热液矿床大部分位于乌兹密尔-杜克塔尔岩浆弧和阿尔博兹岩浆弧.其中,前者主要产出高硫型Cu-Au±Ag矿床和低硫型Au±Ag±Cu矿床,分布较为稀疏,成矿与始新世和中新世热液活动有关,部分高硫型矿化可能与临近的斑岩型铜矿化构成一套斑岩铜成矿系统;后者主要发育高硫型Cu-Au±Ag矿床、低硫型Au±Ag±Cu矿床、中硫型Pb-Zn±Cu±Au±Ag矿床,它们集中分布在西部的Tarom-Hashtjin带和东部Torud-Chah Shirin带,成矿主要发生在始新世,矿体均赋存在火山岩中且明显受断裂控制,但在矿石矿物和脉石矿物的种类、组构特征以及蚀变类型等方面存在差异,金属沉淀均与降温、沸腾和流体混合等密切相关.     

新疆鄯善县石英滩金矿床地质特征及控矿因素

通过对石英滩金矿床区域地质背景、矿体产出形态、矿石特征、成矿控制因素的研究，认为矿床成因类型应属浅成低温火山热液型金矿床。     

西藏多龙矿集区发现浅成低温热液型铜(金银)矿床

根据2013年最新勘查成果、详细的地质编录,对西藏多龙铜金矿集区铁格龙南(荣那)铜(金银)矿床地质特征、矿床类型进行了初步研究,认为该矿床是斑岩-浅成低温热液成矿系统的产物,是典型的高硫型浅成低温热液矿床。矿床规模巨大,矿石中发育条带状、层纹状、皮壳状、致密块状明矾石、地开石,深部发育黄铁绢英岩化,黄铁矿的含量为3%~35%,矿石矿物由铜蓝、蓝辉铜矿、硫砷铜矿、斯硫铜矿、雅硫铜矿、久辉铜矿、斜方蓝辉铜矿、斑铜矿、黝铜矿、黄铜矿等组成。综合研究表明,推断浅部或外围发育独立的高硫型浅成低温热液型金矿,深部存在斑岩型铜(金银)矿体。该矿体的发现结束了西藏至今没有发现典型浅成低温热液矿床的历史,对区域找矿具有极其重要的指导意义。     

兰坪金顶超大型铅锌矿床含矿岩石沉积特征

云南兰坪金顶超大型铅锌矿含矿岩石的成因一直存在正常沉积和非正常沉积两种对立的观点。为了查明其成因,从矿区开采露头和岩芯观察描述出发,以矿区填图为基础,通过对含矿岩石的岩石学特征、粒度和沉积构造等相标志分析,确定了金顶超大型铅锌矿含矿岩石属于湖底扇深水重力流沉积,并识别出非沟道体系的液化流和沟道体系的砂质碎屑流、浊流等类型,进一步划分出内扇、中扇和外扇三个亚相。该湖底扇平面展布为自矿区东部至西部粒度明显由粗变细,岩性由厚层—块状灰岩岩块构成的角砾岩相逐渐过渡到交错层理发育的中细粒砂岩相,其中砂质碎屑流沉积体具有良好的储集层物性特征,亦是重要的含矿岩石,具有广阔的勘探前景。     

云南澜沧江中南段多金属成矿谱系分析

基于GIS空间分析技术,对云南澜沧江中南段多金属矿床的赋矿地层时间谱系、容矿构造空间谱系和矿床成因谱系进行了较系统的分析.研究表明,下-中元古界、三叠系、泥盆系、二叠系是本区最重要的赋矿层位,有两个聚矿期和多个时代地层含矿的特点,不同时代地层的含矿性具有多样性和专属型特征,元古宙火山沉积为主的建造是铁-铜、钨-锡矿为主的赋矿层位,晚古生代-中生代早期是沉积、裂谷火山活动强烈时期,金、铜、铅、锌、银、汞、锑、钨、锡多金属矿床高度聚集.自东向西为中生代坳陷区金、铜、镍成矿带,思茅-龙洞河晚古生代-三叠纪沉积盆地铜、铅、锌、银成矿带,岩浆弧地块钨、锡、铅-锌、铁成矿带,浅变质岩基底铅-锌-银、铁成矿带,被动边缘活动带金、铅-锌-银、锡成矿区和保山-镇康微地块铅-锌、铜、铁、汞成矿带,构成了容矿构造空间谱系.全区多金属矿床有沉积、沉积改造、岩浆-变质热液、火山沉积-火山热液四大成矿谱系,14种成矿类型,铜多金属、铅-锌-银、锡-钨矿床是研究区最具找矿前景的优势矿种.     

A Low‐Sulfidation Epithermal Mineralization in the River Reef Zone,the Poboya Prospect,Central Sulawesi,Indonesia: Vein Textures,Ore Mineralogy,and Fluid Inclusions

The Poboya Prospect lies along the North Northwest ‐ South Southeast Palu‐Koro Fault Zone in the central part of the West Sulawesi Arc. The geology of the area consists of the Palu Metamorphic Complex overlain by the Paleogene‐Neogene Tinombo Formation of volcanosedimentary rocks, the Celebes Molasse sediment, and Late Cenozoic granitic rocks. Petrography, scanning electron microscope with energy‐dispersive spectrometry (SEM‐EDS), electron probe microanalyzer (EPMA), and fluid inclusion microthermometry were carried out to examine vein textures, ore mineralogy, and characteristics of the ore‐forming fluid responsible for mineralization in the River Reef Zone, the Poboya Prospect. Textures of quartz‐carbonate veins in the River Reef Zone include massive micro‐comb, moss, colloform, crustiform, mosaic, feathery, flamboyant, lattice bladed, ghost bladed, parallel bladed, and saccharoidal textures representing primary growth, recrystallization, and replacement. The homogenization temperature and fluid salinity are 240–250°C and 0.3–0.7 wt% NaCl eq., respectively. Ore minerals precipitated in the early stage consist of electrum, naumannite‐aguilarite, chalcopyrite, pyrite, marcasite, sphalerite, and pyrrhotite. Apart from pyrrhotite, these ore minerals were also precipitated in the late stage along with selenopolybasite, freibergite, argyrodite, pyrargyrite, and galena. Selenium more preferably occurs as the crystallographic replacement of sulfur in naumannite‐aguilarite, argyrodite, pyrargyrite, selenopolybasite, and freibergite instead of as independent selenide minerals. The low‐sulfidation epithermal deposit in the River Reef Zone, the Poboya Prospect, illustrates the potential of the West Sulawesi Arc, particularly along the Palu‐Koro Fault Zone, to host epithermal gold mineralization.     

中国东部中生代浅成热液金矿的类型、特征及其地球动力学背景

中国东部中生代浅成热液金矿可以划分为与花岗岩和与碱性岩有关的两种类型；也可以分为高硫型和低硫型两大类，而且以后一种为主。这些金矿的形成和分布受区域构造制约，具体地说是受破火山口、火山角砾岩筒以及与火山机构有关的断裂控制。成矿围岩为火山岩类及同源花岗质岩石和周围地层。主要的蚀变组合为冰长石一玉髓一绢云母或明矾石一高岭石一石英(玉髓)。成矿年龄分布在180～188Ma，135～144Ma，127～115Ma和94～105Ma四个区间，前三组年龄分别响应于中生代华北板块与扬子克拉通的造山碰撞后陆内造山的伸展过程、构造体制大转折以及岩石圈大减薄，后一组为华南地区岩石圈再一次强烈伸展期间的产物。虽然这些矿床的形成时间有差异，但都是发育于大陆伸展环境中。     

滇东南底圩金矿地质特征及找矿预测

底圩金矿是滇东南地区目前发现的少有的中大型金矿,矿石元素组合为砷金型,成因上属浅成（中）低温热液（超）微细浸染型金矿。从矿床地质特征出发,结合邻区资料探讨了矿床的控制因素：(1)底圩金矿与沿向北突出的文山-富宁弧形逆冲推覆构造带圈层状产出的多个金矿带应是统一的有机体,逆冲推覆构造是控制矿床成带产出的主要因素,较为完整的短轴破背斜是矿床定位的极好场所,破背斜轴部不同方向断裂交汇区、背斜转折端、倾伏端以及古喀斯特溶洞发育之处是极好的容矿空间; (2)节理、裂隙、孔隙发育的峨眉山玄武岩是最主要的赋矿岩石,主成矿期应为燕山晚期;(3)低温相对封闭、稳定的环境是形成（中）低温元素组合微细浸染金矿所必须的物理环境。矿区深边部及外围找矿预测应紧紧围绕底圩破背斜轴部不同方向断裂交汇区、背斜转折端、倾伏端以及古喀斯特溶洞发育地段开展工作,除考虑玄武岩赋金外,还应考虑P₂β与P₁m的下伏不整合面和上覆三叠系地层。并探讨了矿区深边部及外围找矿预测应注意的地质物化探标志问题。     

山东省齐河—禹城地区矽卡岩型铁矿成矿预测

山东省德州市齐河—禹城深覆盖区发育有明显的航磁异常和重力异常;近年来地勘单位对该区地球物理异常进行综合研究认为该区具有良好的矽卡岩型铁矿成矿地质条件。通过系统的异常查证工作,在研究区深部揭露了多处矽卡岩型铁矿床,从而找矿工作取得了重大突破,同时科研工作也取得了较大进展。本文旨在通过综合分析区内勘查研究成果进行成矿预测,以期指导区内今后矽卡岩型铁矿勘查工作。勘查工作表明研究区内铁矿体总体表现为“地层、侵入岩和构造”三者联合控矿的特征,即铁矿体赋存于奥陶纪(及石炭纪—二叠纪)地层中、燕山晚期闪长岩体中、奥陶纪(及石炭纪—二叠纪)地层和侵入岩体接触带处附近;通过分析该区赋矿地层、成矿地质体及控矿构造等主要控矿因素,并在对比区内重磁异常和铁矿体相关性的基础上,建立了研究区矽卡岩型铁矿综合找矿预测模型。在对该区地质矿产特征、重力场特征、磁场特征等方面综合分析的基础上进行了成矿预测工作,圈定了李屯、潘店、大张3个Ⅰ级铁矿找矿靶区和薛官屯Ⅲ级铁矿找矿靶区。同时,进一步圈定了李楼西、石庄、郭店村、丁寺东南、大张村、朱庄南共6个最小预测区,本次成矿预测研究工作为今后区内矽卡岩型铁矿找矿工作指明了方向。     

Role of basement in epithermal deposits: The Kushikino and Hishikari gold deposits, southwestern Japan

The magma–ore deposit relationship of most low-sulfidation epithermal ore deposits is still unclear, partly because many stable isotopic studies of such deposits have indicated the predominance of meteoric waters within hydrothermal fluids. However, it is certainly true that hydrothermal systems are ultimately driven by magmatic intrusions, and epithermal gold deposits might therefore be produced by magmatic activity even in deposits having has no obvious links to a magma. We re-examine the genesis of two typical low-sulfidation epithermal gold deposits, the Kushikino and Hishikari deposits, using structural simulations and isotope data.Many epithermal gold deposits including the Kushikino and Hishikari deposits have been discovered in Kyushu, southwestern Japan. The Kushikino deposit comprises fissure-filling veins within Neogene andesitic volcanics that overlie unconformably Cretaceous sedimentary basement. The veins consist of gold- and silver-bearing quartz and calcite with minor amounts of adularia, sericite and sulfides. Although carbon and oxygen isotopic data for the veins indicate a meteoric origin of the ore fluid, finite element simulations suggest that the vein system might have formed in direct response to magma intrusion. In particular, geophysical data suggest that intruding magma has uplifted the basement rocks, thereby producing fractures and veins and a positive Bouguer anomaly, and providing the heat necessary to drive an ore-forming hydrothermal system.The second component of this study has been to investigate the nature and evolution of the Kushikino and Hishikari epithermal systems. Isotope data document the geochemical evolution of the hydrothermal fluids. We conclude that the existence of sedimentary basement rocks at depth might have affected the strontium and carbon isotopic ratios of the Kushikino and Hishikari ore fluids. The ⁸⁷Sr/⁸⁶Sr ratios and δ¹³C–δ¹⁸O trend reveal that major ore veins in the Hishikari deposit can be distinguished from shallow barren veins. It was suggested isotopically that fluids responsible for the barren veins in nearby shallow and barren circulation systems were only controlled by the shallow host rocks. Such multi-isotope systematics provide a powerful tool with which to determine the center of hydrothermal activity and thereby document the evolution of hydrothermal fluids.     

中国与火山岩—斑岩有关的金银多金属矿成矿地质特征

与火山岩—斑岩有关的金银矿矿集区和大型矿床的形成是多种因素综合作用的结果,特别是火山盆地类型及结构、大地构造背景、基底断裂、火山岩岩相和岩类、基底矿源层、火山机构内部构造、流体系统等对于矿床的形成起着决定性的作用。上叠式火山盆地能否成矿,关键是基底是否具备初始矿源层,岩浆是否起源于上地幔并同熔了老基底中的矿源层。继承性火山盆地能否形成金银矿,关键在于上下两套建造中火山岩的发育程度和火山—沉积建造的连续性,一般底部构造层中发育玄武岩、科马提岩、枕状熔岩等中基性、碱性火山岩,顶部构造层以中—酸性火山岩为主时,对成矿有利。大地构造位置上为两个构造单元的接合部位,与金银矿成矿有关的火山盆地或其基底都经历过裂陷拉张环境,不管是盖层还是基底,必有其一为裂谷或岛弧环境岩石建造。许多中大型矿床和矿集区都分布在多次开合的裂谷环境中。斑岩体岩石类型、成分、形态、产状控制矿体的定位和展布,潜火山岩、斑岩体与金银矿存在空间上的不可分割性、时间上的同一性和成因上的内在联系。单一的火山熔岩很少形成矿床,形成金银矿床的火山岩常为凝灰岩、凝灰质集块岩、凝灰质火山熔岩,岩相上常为从火山岩向沉积岩过渡的地方,岩石组合为火山碎屑岩+凝灰岩+杂砂岩、粉砂岩+熔岩+泥质岩+碳酸岩。“三重结构”构造控矿,即深层次基底断裂,中深部位的盖层断裂,超浅、近地表—地表构造。以火山机构为中心从下向上形成多位容矿裂隙：侵入体(斑岩)顶部裂隙系统,隐爆角砾岩筒裂隙系统,破火山口裂隙系统。潜火山岩发生多期隐爆形成具一定延深的角砾岩筒,往往存在多个热流体系统,补给系统和排放系统完全时对成矿有利。     

茶尖岭矿区后水矿化点铜银多金属成矿条件分析及远景初探

茶尖岭矿区后水矿化点铜银多金属矿属于浅成热液脉型成因,通过矿床形成的热源、水源、矿源的信息标志分析了后水矿化点铜银多金属成矿条件。认为该矿化点铜银多金属成矿的热源、水源、矿源条件均较充足,指出找矿有利地段。     

Regional Metallogenesis of the Chang’an Gold Ore Deposit in Western Yunnan: Evidences from Fluid Inclusions and Stable Isotopes

<正>The Chang'an gold ore deposit in western Yunnan is located at the southern segment of the Ailaoshan metallogenic belt.The ore bodies are preserved in fractured Ordovician sedimentary clastic rocks.The gold-bearing minerals occur dominantly in sulfide-quartz veins.Fluid inclusion analysis shows that the Chang'an gold ore deposit is characterized by epithermal gold mineralization at temperatures between 200℃and 280℃at a shallow crustal level.The mineralizing fluids have intermediate to low salinity(6%-18%) and low densities(0.72-1.27 g/cm~3).The ore minerals haveδ~(34)S in a range from -13‰to 3.57‰,concentrated from -2.06‰to 3.57‰with an average of 1.55‰.The ~(206)Pb/~(204)Pb,~(207)Pb/~(204)Pb and ~(208)Pb/~(204)Pb values are 18.9977-19.5748,15.7093-15.784,39.3814-40.2004 respectively.These isotope data suggest that the ore-forming elements were mainly derived from mixed crustal and mantle sources.The Chang'an gold ore deposit and Tongchang Cu-Mo deposit are closely related to each other in their spatial distribution and age of formation.They have similar sources of mineralizing elements and identical ore-forming metal elements,and show a close relationship in physical and chemical conditions of mineralization.The two deposits constitute an epithermal-porphyry -skarn type Cu-Mo-Au mineralization system in the Tongchang-Chang'an area,which is related to the Cenozoic high-K alkaline magmatism.