【作者】 曹养同；

【导师】 刘成林； 焦鹏程；

【作者基本信息】 中国地质科学院 ， 矿物学、岩石学、矿床学， 2010， 博士

【摘要】 中国铜矿资源丰富,但仍然不能满足国内经济增长的需求,近几年国内铜原料62%依靠进口,所以铜矿仍然是国内比较短缺的矿种之一。统计资料表明：砂页岩型铜矿无论从数量、储量上,是仅次于斑岩型铜矿的第二大铜矿床类型。新疆库车盆地新近系碎屑岩地层中发育众多的砂岩型铜矿化,而拜城小型滴水铜矿自清朝末年就已开采,这种砂岩型铜矿化与盆地大量分布的蒸发岩有着密切的联系。所以寻找以铜为主的金属矿产,从蒸发岩体系与金属成矿的角度出发,研究库车盆地蒸发岩体系与砂岩型铜等金属成矿作用的关系,从而为我国铜矿勘探与开发开辟新的途径。新疆库车盆地古近系-新近系吉迪克时期发育一套巨厚的蒸发岩沉积,盐、膏层厚度变化从几十米至两千多米。其上覆新近系吉迪克组、康村组砂岩中发育一系列铜矿化。野外调查及室内分析表明：砂岩型铜矿化基本位于盐丘附近,沿近东西向断裂带分布；盆地铜矿物主要为与干旱气候条件及卤水有关的氯铜矿(Cu2(0H)3C1)；地表灰岩断裂破碎带上氯铜矿和残余结晶盐岩共存：近垂直砂岩层面的节理面上充填石膏,氯铜矿浸染于石膏表面或石膏之中；新近系后生石膏团块中含有氯铜矿或自然铜,或砂岩裂隙中渗出卤水,在裂隙处发育氯铜矿；电子探针分析显示氯铜矿为自生化学沉积,呈脉状、树枝状充填于砂岩的裂隙中；盆地近东西向断裂带上发现硫化氢气体溢出,附近自然硫、碳酸钙矿物沉淀,在自然硫样品中发现CuS(铜蓝),说明地层深部硫酸盐还原反应存在,其产物沿断裂构造运移并能为Cu富集提供还原环境。扫描电镜分析,首次在库车盆地蒸发岩样品(地表盐丘采集的盐岩样品,石油钻井4412米深的膏岩样品,及地表结晶的盐壳样品)中发现金属矿物,包括氯铜矿,铜、锌、银等金属的硫化物,自然金等。上述现象说明砂岩型铜等金属矿化、蒸发岩、断裂构造密切相关。要解释上述地质现象,回答砂岩型铜等金属矿化、蒸发岩、断裂构造之间的关系,需要对库车盆地蒸发岩的发育规律、砂岩型铜矿化特征、矿化机理,特别是蒸发岩体系(蒸发岩体、围岩、围岩中的断裂构造)与砂岩型铜矿化的关系有一个深入的研究,最关键的是解决蒸发岩体系在砂岩型铜成矿过程中所起的作用,从而解决蒸发岩体系能否成金属矿的问题。根据以上目的,采取以下研究方法。1、野外调查库车盆地盐丘及铜矿化分布特征,铜矿化与蒸发岩的关系,矿化在新近系碎屑岩的分布特征,采集泉水、卤水、盐霜、铜矿化样品、蒸发岩和碎屑岩样品,对出露盐丘剖面、盆地碎屑岩剖面测量、取样。2、室内利用扫描电镜、薄片分析、X衍射、电子探针、同位素分析、固样水样化学分析、蒸发淋滤实验等手段,查明固体样品中矿物成分、组成、结构构造等,分析水样、固样中各元素含量变化关系,卤水来源,矿源层和含矿层,盐、膏中铜矿化成因,铜的淋滤条件、富集沉淀环境。同时依据蒸发岩沉积旋回划分及空间模型建立研究蒸发岩在时空上的变化关系。研究结果表明,蒸发岩赋存的层位主要为古近系库姆格列木群、苏维依组、新近系吉迪克组。蒸发岩类型主要为石盐岩和膏岩,少量白云岩和灰岩,含有钙芒硝、硬石膏、钾石盐、光卤石、杂卤石、钾石膏及氯化钙等矿物。通过对盆地古近系—新近系蒸发岩沉积旋回研究,共识别出5期沉积旋回,其中I1、I2沉积旋回位于库姆格列木群(E1-2k,I3旋回位于苏维依组(E2-3s),I4、I5旋回位于吉迪克组(N1j)。库姆格列木时期,盆地西部的I2旋回在I,旋回基础上向南北方向扩展；苏维依时期,盆地西北部基底抬升,卤水迁移导致沉积区一分为二,分别向盆地南部、东部迁移,发育I3旋回；吉迪克时期,盆地南部、东部的两个沉积区继续发育巨厚的蒸发岩沉积(I4旋回)。盐、膏矿体空间展布模型显示：矿体起伏趋势与秋里塔格构造带、克拉苏构造带相一致,同时反映出库姆格列木时期,库车盆地西部蒸发岩沉积曾经有两个中心,分别位于西部盆地的拜城附近和拜城南部附近,新近系的吉迪克时期,库车盆地东部出现两个蒸发岩沉积中心,位于轮台北部附近和库车东部附近。盆地这种东西部次级沉积中心发育的地方,应为库车盆地次级的蒸发岩沉积盆地,而钾盐的富集一般产于大的盆地内这种次级的构造单元。野外调查和室内研究表明：库车盆地共有2个小型铜矿,8处铜矿化点,其中新发现铜矿化点2处(克孜尔铜矿化点和阿格铜矿化点)；铜矿化的分布与盐丘紧密相邻,位于南北两大构造带上,沿断裂构造带呈近东西向展布。主要发育3种成因类型：灰岩型、砂岩型、泥岩型。铜矿物主要有氯铜矿、蓝铜矿、自然铜等。矿化层位主要位于中、上新统的康村组,部分位于中新统的吉迪克组,位于背斜的轴部或偏向两翼的部位。矿源层为蒸发岩、沉积岩(主要为褐红色粉砂岩、褐红色泥岩)。基本的含矿层为灰绿色粉砂岩、细砂岩、灰白色中粗砂岩。卤水来自盆地中原生沉积卤水及大气降水溶解蒸发岩形成后生溶滤卤水,南天山含铜老地层提供了铜的初期物质来源,褐红色碎屑岩、蒸发岩提供了铜的后期物质来源。含铜卤水运移的动力主要有晶间脱水作用、盐体负荷卸载作用、构造挤压作用。吉迪克晚期的断裂构造形成含矿卤水有利的运移通道。盆地古近系一新近系地层中硫酸盐热化学还原作用存在说明当地层深部含铜卤水遇到富含还原硫的卤水时,能形成铜的硫化物,这一点已经被滴水铜矿钻探证实。砂岩型铜成矿作用除了主要与卤水有关外,还与砂岩的原生沉积作用有关。铜成矿时代从晚中新世到上新世中晚期,不晚于早更新世早期。本文研究表明：砂岩型铜及其金属成矿作用离不开蒸发岩体系(蒸发岩体、围岩、围岩中的断裂构造),蒸发岩体系能够成矿。更多还原

【Abstract】 There are abundant copper resources, but it is not given a approving requirement to increase of economy in China, and about 62% material of copper is imported now, so the copper ore is still one of much lack ore sorts. The datum of Stat. makes shown that sandstone-type mineralization is the second largest in copper ore sorts than Porphyry copper deposit either amount or reserves. Many sandstone-type coppers had been developed in fragmentary rock in Neogene in Kuqa Basin, especially Baicheng Dishui small copper, has been exploited from Qing dynasty, and these are closely contacted with much evaporates in the Basin. So searching for metal mineral or copper, and researching the connection between evaporates systems and sandstone-type copper et al. metallization, it is given a new research domain which has been cut on copper prospecting.Evaporates sediment with gigantic thickness had been developed in Kuqa Basin from Paleogene to Neogene period and the thickness of salt or gypsum changes from tens of meters to two thousands meters. A series of copper mineralization has been developed in sandstones in Jidike Group and Kangcun Group in Neogene. It is well known that by field investigation and indoor analysis, the mineralization lies near by salt domes and distributes on structure belt from west to east, and the main copper mineral is Atacama (Cu2 (OH)3 Cl) which is also connected with brain and drought climates, not only has the Atacama been born with crystal remains of brain in structure belt of limestone, but also dip-dyed in gypsum which had been full of joint planes of sandstone, the Atacama and native copper are lied in epigenetic gypsum gobbet or the former lies in cranny of sandstone which the brain exuded, it is primary chemical sediment for Atacama and filling of cranny of sandstone with nervation or arborization by analyzing with Electron probe, sulfureted hydrogen is overflowing from structure belt, native sulfur and calcium carbonate are depositing, covellite (CuS) is found in native sulfur, all this give a conclusion that thermochemical sulfate reduction has been in existence, the outcome move by breakage and so reducing environment come into being, Some metals including Atacama, copper, zinc, silver, uranium and native gold are discovered in samples of evaporates including salt samples of salt domes, gypsum samples in petroleum drill holes with depth 4412 meters, and salt shell samples forming in the earth’s surface in the first in Kuqa Basin. These tell us that metals or sandstone-type copper mineralization are close connection with evaporates and breakage.For the seek of explaining these geological phenomena and giving a approving answer for the relations on metals or sandstone-type copper mineralization, evaporates, and faults, we need to research the development rules of evaporates, characteristics and mechanism of sandstone-type copper mineralization, especially the relations on evaporates systems (evaporate body, wall rock, and faults of wall rock) and sandstone-type copper mineralization, and the key is the action of evaporates systems in the courses of sandstone-type copper mineralization, and so resolve the issue weather the evaporates systems can make metal ore or not.For the purpose some techniques are used. First distribution characteristics of salt domes, relations on evaporates and copper mineralization, distribution characteristics of fragmentary rock in Neogene by field investigation, and collecting some samples such as spring, barine, salt frost, copper mineralization or evaporates samples, and measuring sections, collecting some samples of salt domes or fragmentary rock. Second, indoor analyzing the samples by SEM, slice analysis, X diffraction, Electron probe, isotopes analysis, chemistry analysis of solid and water samples, and experiment on evaporation and leaching, and so we can find out mineral component, compose, configuration, conformation, et al. of solid, variety relations on elements of water samples, origin of brain, ore sources and ore-hosting, cause of formation of copper mineralization in salt and gypsum, conditions and environment of copper leached and enriched. In the same time, we can research diversification of evaporates in space time by division of evaporates sedimentary cycle and establishment of dimensional models.As a result for the research, the stratum of evaporates lie in mainly Kumugeliemu group, Suweiyi group in Paleogene, and Jidike group in Neogene. The-types of evaporates are main halite, gypsum, and a few dolomite and limestone, comprised of some minerals such as brongniartine, anhedritite, carnallite, halo-sylvite, kaluszite, and hydrophilite. By studying for sedimentary cycles of evaporates from Paleogene to Neogene in the basin, five cycles are identified, andⅠ1 andⅠ2 cycles lying in Kumugeliemu group,Ⅰ3 cycle in Sweiyi group,Ⅰ4 andⅠ5 cycles in Jidiek group.Ⅰ2 cycle was expanded from north to south based onⅠ1 cycle in Kumugeliemu period, accompanying with the floor has been raised in the northwest of the basin, brine began to move so that two sedimentary areas came into being, accordingly, the areas began to move by oneself from northwest to south and east, in Jidike period the evaporites sediment with gigantic thickness had kept on development in the areas. The space model of salt and gypsum are showed that the undulate trend of orebody is consistent with Qiulitage and Kelasu tectonic zone, and two sedimentary centre which lie in Baich and in south of it are reflected in the west of the basin in Kumugeliemu period, so is it in the east of the basin in Jidike period, but its sedimentary centre lie in Luntai and in north of it.Two mini-type copper ores and eight copper mineralization spots are discovered in the Basin by field investigation and indoor analysis, that the Kezier copper mineralization spot and Age copper mineralization spot are the first discovered, and the distribution of mineralization is near by salt domes which lie in two big tectonic zone from north to south and spread out from west to east. Four sorts of mineralization had been developed including limestone type, sandstone type, mudstone type, and sulfide type comprised quartz reef. the main copper minerals are Atacamite, azurite, and native copper. Kangcun group of Pliocene is main ore bed, and the other is Jidike group of Miocene, which lie in alar part near by axis part of anticline. The evaporates, maroon siltstone, and maroon mudstone are source bed and the essential ore beds are celadon siltstone, fine stone, and grey grit stone.The brine roots in primary bittern and evaporates dissolved by atmospheric water, the first origin of copper come from old copperish stratum of the south Tianshan tectonic belt, and the evaporates, maroon fragmentary rock offer the second origin of copper. Intergranular dehydration, unload of salt body, and tectonic extrusion are main momentum on movement of coppery brine. The good channels for ore brine are rift, fracture zone of late Jidike period. It is a hint that Coppery sulfid would come into being when brine enriched copper ions had happened to brine enriched sulfidion in deep stratum by discovering existence of thermochemical sulfate reduction(TSR) in Kuqa Basin from Paleogene to Neogene, and these are already approved by drilling for copper ore in Dishui.The sandstone-type copper metallization, not only connected closely on brine, but also related with prime deposition of sandstones. The metallization epoch is from later Miocene to middle or later Pliocene, and not later than forepart of Pleistocene. In this article the metals especially sandstone-type copper metallization in sandstones are not detached from evaporates systems (evaporates body, wall rock, and fracture structure), and it is possible that metallization can happen in the systems.更多还原