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1.
阿舍勒是新疆十分重要的铜多金属矿集区,矿化均赋存于下–中泥盆统阿舍勒组火山岩系中。矿化类型多,成矿元素组合复杂(Cu、Cu-Zn、Cu-Zn-Au、Cu-Pb-Zn-Au、Cu-Pb-Zn-Ag)。阿舍勒组火山活动时间是402~375 Ma,矿化时间为394~379 Ma,持续了15 Ma。本文通过对阿舍勒铜锌矿和萨尔朔克金多金属矿的系统研究,提出阿舍勒矿集区矿床模型,认为尽管矿集区铜多金属矿化类型多,成矿元素组合复杂,但成矿均与火山作用有关,属同一VMS成矿系统,只是不同部位存在矿化差异。在火山斜坡和洼地喷流沉积形成层状铜锌矿体和重晶石矿体,补给通道中形成脉状铜(锌)矿体和铜铅锌银矿体,潜流纹岩中形成脉状金铜铅锌矿体,潜英安岩中形成铜矿体,潜火山岩接触带形成铜矿体,在断裂或裂隙中形成铜矿体。  相似文献   

2.
The Ashele Cu-Zn deposit is a typical VMS deposit in Chinese Altay located in the southern margin of the Altaid orogen. The deposit occurred in the polyphase fold system, and the main orebody is located at the hinge of the syncline. All orebodies show lenticular form, and are stratabound by a suite of early to middle Devonian bimodal volcanic rocks. The hosting basalt is low K tholeiite and characterized with high Mg, Fe, Ca and low K, Ti. These basalts show flat REE pattern with Ce negative anomaly (Ce/Ce* 0.73–0.76). Niobium, Ta, Zr, Hf are depleted and Rb, Ba, Th, U, Sr, Pb are enriched with respect to the N-MORB. Both the Sr and Nd isotopes show depleted properties, while the (87Sr/86Sr)i and the εNd(t) range from 0.70469 to 0.70488 and 4.6 to 5.3, respectively. All geochemical and isotopic data from the hosting basalt show that it originates from an island arc source. We also report the S isotope data from the massive orebody, and δ34S‰ change from 1.8‰ to 5.6‰. The S isotope data provide evidence that the sulfur originates from a mixing source between magma and seawater sulfate. We propose that the mafic magma provides the ore-forming metal and some percentage of sulfur, while it also acts as a heat engine which makes the fluids leach the metal from the underlying volcanic rocks. Combining the geological characteristics of the Ashele and geochemical data, and comparing with other Cu-Zn VMS deposits in the world, we propose that Ashele formed in a rifted arc setting.  相似文献   

3.
阿舍勒铜锌块状硫化物矿床地质特征和成因   总被引:20,自引:3,他引:20  
阿舍勒矿床与早-中泥盆世双峰式火山活动有着成因联系,产于火山洼地中,它在喷气-沉积阶段形成,后又细历了变质改造和岩浆热液叠加。矿床具有双层结构,很好的矿化分带和刨变分带。成矿流体的温度,压力和酸碱度等物理化学条件变化引起了围岩蚀变和矿石堆积,在海底界面上下形成了具有成因联系的两套矿化。  相似文献   

4.
海相火山-沉积建造铁铜矿床类型及地质特征   总被引:4,自引:1,他引:4  
于浦生  邬介人 《地球学报》1996,17(Z1):50-56
铁-铜型矿床产出的时代从元古宙到新生代均有,与其有关的火山岩大多数为中基性与中酸性或偏碱性岩石。作者以镜的山桦树沟、陇山陈家庙和陕西铜厂不同时代的铁-铜矿床为例,概述了该类型矿床的地质特征、成矿环境并着重探了铁-铜矿床的成因机制,认为该类型矿床是与火山作用有关的喷气-沉积型矿床,同时指出柳沟峡地区及其以西(东缰地区)铁-铜型铜矿化带的发现,是进一步寻找铁-铜-金矿床的有利地段。  相似文献   

5.
王登红  陈毓川 《矿床地质》2001,20(2):112-118
文章初步厘定了与海相火作用有关的铁、铜、铅、锌矿床成矿系列类型的概念,并对其进行了分类,讨论了其成因,认为内生外成(沉)是其主要特征,即成矿物质主要由火山作用从深部提供,而矿石又是通过沉积作用在海底形成的。在一定程度上,可从成矿类型的角度将块状硫化物矿床与BIF型或磁铁石英岩型矿床联系起来考虑。该类矿床成矿系列类型的演化特点在一定程度上可以反映地球演化的历史轨迹。  相似文献   

6.
新疆阿舍勒铜矿区双峰式火山岩与成矿背景的初步研究   总被引:13,自引:1,他引:13  
王登红 《地质论评》1996,42(1):45-53
新疆阿舍勒铜矿是我国近十多年来找到的一个大型海相火山岩型块状硫化物多金属矿床,在经济上和矿床学上都有重要意义。阿舍勒铜矿的容矿岩是早-中泥盆世阿舍勒组海相火山岩,具特征的双峰式组合,缺少含SiO254%-61%的中性岩,在地表和钻孔都经常见到基性与酸性火山岩紧密互层现象。稀土和微量元素地球化学表明基性、酸性火山岩来自两个不同的源区。矿石铅同位素组成与细碧岩一致,硫同位素呈典型塔式分布,表明成矿物质  相似文献   

7.
8.
Abstract. The Takara volcanogenic massive sulfide (VMS) deposit occurs in Miocene formation of the Misaka Mountain, the South Fossa Magna region, central Japan. The tectonic setting of the Misaka Mountain is reconstructed to be a part of the paleo Izu-Ogasawara arc which collided with the Honshu arc and to form accreted body in the present position. The Takara deposit, therefore, is considered to have formed in the paleo Izu-Ogasawara arc.
The ores from the Takara deposit are classified into pyrite-type ore, chalcopyrite-type ore, and sphalerite-type ore on the basis of chemical composition and their mineral assemblages. Some pyrite-type ores are characterized by their high Au content. The Au content is hardly recognized in the chalcopyrite-type and sphalerite-type ores.
The ores from the Takara deposit have intermediate bulk chemical composition between those from the Besshi-type deposits and the Kuroko-type deposits that are two representative VMS deposits. However, the bulk chemical composition is closer to that from the Kuroko-type deposits. And moreover, chemical composition of tetrahedrite-tennantite series minerals (tetrahedrite) is similar to that from the Kuroko-type deposits. The bulk chemical composition (Cu, Zn, Co, Pb, and As contents) of ores is affected by the chemical composition of volcanic rocks associated with VMS deposits.  相似文献   

9.
侯增谦 《地球化学》1996,25(3):228-241
选择西南太平洋冲绳海槽现代海底烟囱硫化物矿床、日本小坂矿山上向黑矿(第三纪)和中国西南呷村黑矿型矿床(三叠纪)进行了矿石地球化学比较研究。黑矿型矿床矿石吨位-品位模式与其他火山成因块状硫化物(VMS)矿床类似,矿田(20-50km^2)矿石吨位与单个喷气-沉积型(Sedex)矿床相当,金属总量4-6Mt,为矿田范围内热液流体搬运的最大金属量。与洋脊环境VMS矿床相比,岛弧裂谷环境产出的黑矿型矿床相  相似文献   

10.
The Devonian volcano-passive continental margin in southern Altay is a significant volcanogenic massive sulphide metallogenic belt. Acidic volcanism has been dominant on the inner side of the volcano-passive continental margin, i.e., near the old land, resulting in a Pb-Zn metallogenic sub-belt, in which the ore deposits are hosted by sedimentary rocks in volcanic series, as represented by the large Koktal Pb-Zn deposits. In the central part of the margin far away from the old land, bimodal volcanic formations are well developed, forming volcanics-hosted Cu-Zn metallogenic sub-belts, e.g., the large-scale Ashele Cu-Zn deposit. The Qiaoxiahala sub-belt on the outer side of the margin near the ocean ridge is located at the spreading central trough, where ophiolite suites are developed. This type of deposits is rich in gold and copper, similar to the Cyprus-type Fe-Cu-Au metallogenic sub-belt in metallogenic environment (represented by the Qiaoxiahala medium-scale Fe-Cu-Au deposit). From the old land to th  相似文献   

11.
上庄坪铅锌银矿床是新一轮国土资源大调查中在北秦岭二郎坪群发现的硫化物矿床。笔者通过对矿床矿石、容矿同岩、重晶石岩的微量、稀土元素地球化学特征分析和地质特征研究,探讨成矿构造环境、成矿物质来源及矿床成因问题。研究表明.矿石和容矿围岩稀土元素球粒陨石标准化组成模式均为右倾型.矿石与围岩在Cu-Pb-Zn判别图解中投点区域一致.矿石Zn/(Zn Pb)与冲绳海槽和上向黑矿矿石特征相似、与TAG和EPR13°N区硫化物存在差异.矿石具较高As、Sb和Pb与低Cu、Cd和Se元素特征.认为该矿床成矿元素来源于壳幔混合、但以壳源为主的围岩变(石英)角斑岩和变细碧岩。矿石稀土元素、微量元素地球化学特征、矿床地质特征及与热水沉积重晶石岩和硅质岩的紧密共生关系说明,上庄坪矿床是弧后盆地构造环境海底热液喷流成岩成矿作用的产物。重晶石岩、硅质岩、矿床纵向和横向分带是寻找和勘探该类矿床的重要标志和依据。  相似文献   

12.
新疆阿舍勒铜矿区火山岩与成矿   总被引:9,自引:0,他引:9       下载免费PDF全文
王登红 《地质科学》1996,31(2):163-169
阿舍勒铜矿曾被认为是次火山热液矿床。根据岩芯观察研究和同位素、微量元素及稀土元素地球化学研究,认为该矿属海相火山喷气沉积成因,成矿作用与双峰式火山岩密不可分,细碧岩是成矿金属元素的主要来源,而作为沉淀剂的硫主要由酸性火山喷气作用提供。  相似文献   

13.
四川呷村V HMS矿床:从野外观察到成矿模型   总被引:22,自引:11,他引:11  
呷村矿床是一个与晚三叠世海相钙碱性酸性火山岩系有关的典型块状硫化物(VHMS)矿床。热水流体系统和贱金属成矿作用发育于义敦岛弧碰撞造山带上的弧间裂谷盆地内,并受其内部的一系列局限盆地及SN向基底断裂-裂缝系统控制。含矿岩系为双峰岩石组合,具火山碎屑岩-矿体-喷气岩“三位一体”特征。硫化物矿床具有“块状矿席+层控网脉状矿带”式三维结构特征。块状矿席发育多旋回的硫化物-硫酸盐韵律型式,揭示热水流体在海底的幕式排泄以及硫化物-硫酸盐在卤水池内的韵律式化学淀积和滑塌堆积过程。层控网脉状矿带产出于流纹质火山岩系,与上覆的块状矿席平行展布,揭示高渗透性碎屑岩层和多条同级别断层或断裂共同约束海底下部热水流体,并诱导其“弥散式”排泄和侧向流动交代。热水流体的传导冷凝过程导致硫化物沉积、热水流体与冷海水的简单混合导致硅质岩或/重晶石淀积,传导冷凝与海水混合的联合作用导致含硫化物重晶石、硅质岩和红碧玉形成。  相似文献   

14.
黄土坡铜锌矿床是东天山卡拉塔格地区一中型海相火山岩型块状硫化物(VHMS)矿床,赋存于早志留世海相火山-沉积岩系中。矿体产于酸性火山角砾岩与凝灰岩之间,主矿体呈厚大的扁豆状,矿石主要呈块状、浸染状、条带状和网脉状构造。本文报道了黄土坡铜锌矿床成矿流体的氦和氩同位素组成,黄铁矿流体包裹体的3He 含量低,介于0.039×10-12 cm3 STP/g~0.64×10-12 cm3 STP/g,n(3He)/n(4He)值为 0.11~0.94 Ra,介于壳源He与幔源He之间。40Ar 含量变化于 3.49×10-8cm3 STP/g~34.25×10-8 cm3 STP/g 之间,n(40Ar)/n(36Ar)介于301.40~425.98 之间。成矿流体中有幔源 He(1.71%~10.97%)和放射性成因 Ar(40Ar*含量为1.96%~30.63%)。结合矿床包裹体及 H-O-S 同位素特征,认为幔源流体和富放射性成因He 和Ar 的海水参与了成矿。  相似文献   

15.
Abstract. The Re-Os isotopic compositions of sulfide ores were analyzed for the Gacun, a volcanogenic massive sulfide deposit in southwestern China, to constrain the timing of mineralization. Sulfide ores from the deposit have a wide range of Re and Os concentrations, varying from 80.2 to 1543.2 ppb and from 0.307 to 8.83 ppb, respectively, and yielded a limited field of high 187Re/188Os and high 187Os/188Os ratios, ranging from 1452 to 3309 and from 5.77 to 13.24, respectively. All sulfide samples yielded an isochron with an age of 217±28 Ma and an initial 187Os/188Os ratio of around 0.52±0.73. The Re-Os isochron age agrees with ages previously constrained by the other isotopic dating of the host rocks and fossil strata for the deposit. The rhythmic variation in 187Os/188Os and 187Re/188Os ratios within massive sulfide zone records a complicated process for ore-forming fluids episodically vented into the brine pool on the Mesozoic seafloor.  相似文献   

16.
铜陵矿集区块状硫化物矿床地质特征   总被引:3,自引:0,他引:3  
蚀变-流体填图揭示,铜陵地区石炭系黄龙组喷流沉积含矿岩系中普遍存在块状硫化物矿床,上部为层状块状硫化物矿层,下部为浸染状、细脉-网脉状硫化物矿体,具有典型的双层结构。自下而上矿石具有垂直分带性:硅质矿石、石膏矿石、黄铁矿矿石、黄铁矿-重晶石矿石和菱铁矿.铁质燧石矿石。矿石发育胶状和莓球结构,微细层纹状-马尾丝构造。矿石成分以黄铁矿和菱铁矿为主。矿床发育一套独特的热液气爆角砾岩不规则网脉和相互连通的虫管状.树枝状-姜块状黄铁矿管道系统,矿化形式为弥散式多喷口席状矿化,厚度一般不超过100m。  相似文献   

17.
The Cheshmeh-Frezi Mn deposit belongs to the southwest Sabzevar basin to the north of the Central Iranian microcontinent. This basin, which hosts abundant mineral deposits including Mn exhalative and Besshi-type Cu-Zn volcanogenic massive sulfide deposits, followed an evolution closely related to the subduction of the Neo-Tethys oceanic crust beneath the Central Iranian microcontinent. Two major sedimentary sequences are recorded within this basin: (I) the Lower Late Cretaceous volcano-sedimentary sequence (LLCVSS) and (II) the Upper Late Cretaceous sedimentary dominated sequence (ULCSS). The Cheshmeh-Frezi Mn deposit is hosted within red tuff with interbeds of green tuffaceous sandstone of the LLCVSS. Mineralization occurs as stratiform blanket-like and tabular orebodies. Psilomelane, pyrolusite and braunite are the main minerals of the ore, which display a variety of textures. Such as layered, laminated, disseminated, massive, replacement or open space fillings. The footwall and hanging-wall volcanic rocks are predominantly andesite and trachyandesite rocks. Footwall and hangingwall volcanic rocks at Cheshmeh-Frezi are enriched in light rare earth elements (LREEs) compared to chondrite, have steep REE patterns, and generally show Ta and Nb depletions relative to chondrite which are characteristic of back-arc environments. The significant geochemical characteristics of ore such as high Mn content (12.41–33.14 wt%; average 19.41 wt%), low concentration of Fe (0.64–2.27 wt%; average 1.63 wt%), high Ba (49.7–9901 ppm, average 2728.67 ppm), LREE > HREE, and negative Ce and Eu anomalies reveal a primary distal hydrothermal-exhalative source for mineralization. Cheshmeh-Frezi deposit, in comparison with different types of volcanogenic manganese deposits shows broad similarities with the Cuban-type Mn deposits such as tectonic, host and associated rock types, geometry, textures, structures, mineralogy and lithogeochemistry.  相似文献   

18.
The Ohori deposit, one of the base metal deposits in the Green-Tuff region, NE Japan, is composed of two types of mineralization; a skarn-type (Kaninomata orebody) made by the replacement of the Miocene calcareous layer, and a vein-type (Nakanomata orebody). While the ore mineral assemblage of the deposit (chalcopyrite, pyrite, sphalerite and galena) has been known for being rather simple, some Pb-Bi-S minerals have been discovered for the first time in the present study. The minerals mainly occur in the chalcopyrite-rich ores of both orebodies. They essentially belong to the Pb-Bi-S system and contain Cu and Ag in minor amounts, which correspond to the lillianite–gustavite solid solution series (phases Z and X), cosalite, neyite, felbertalite, krupkaite and Bi-bearing galena. The chalcopyrite-rich (Bi-bearing) ores from both orebodies are richer in chalcopyrite, pyrite and chlorite, and have higher homogenization temperatures (>300°C) of fluid inclusions, and higher FeS contents in sphalerite compared to the Bi-free ores. In the Green-Tuff region, Bi-minerals have been reported from many base metal deposits. Most of these Bi-bearing ore deposits are referred to as xenothermal-type deposits, and are characterized by the following common features; composite mineralization of high- and low-temperatures in the shallower environments, and close relationships with the Tertiary granitic rocks. The whole mineralization at the Ohori deposit also has a similar xenothermal character because of the coexistence of high-temperature chalcopyrite-rich ores with Pb-Bi-S minerals, which were formed by the influence of the Tertiary granitic rocks at a shallow depth.  相似文献   

19.
通过对长江中下游成矿带中武山铜矿和冬瓜山铜矿层状矿体的详细研究,发现了大量具有层圈状构造、层纹状构造或不规则同心环状构造的矿石。在前人研究基础上,经光薄片鉴定、扫描电镜观察和碳氧同位素分析等,认为这类矿石在宏观构造上显示出类似于灰泥丘的孔洞系统,微观上又发现了细菌等微生物结构,判断其属于一种矿化的灰泥丘。资料显示,灰泥丘和热水喷流沉积成矿作用关系密切,灰泥丘可视为热水喷流沉积成矿的证据之一。本文所研究的两个矿床中灰泥丘构造矿石保存状况略有不同,冬瓜山铜矿灰泥丘构造矿石保留了大量显示原生热水喷流沉积成因的组构、并发现细菌等微生物结构,碳氧同位素组成也显示原始沉积特征;而武山铜矿灰泥丘构造矿石则显示出强烈受热液改造的矿石组构和碳氧同位素组成特征,暂未发现细菌等微生物结构。冬瓜山和武山铜矿灰泥丘构造矿石的发现,有力地佐证了长江中下游成矿带在海西期曾发生过热水喷流沉积成矿作用。  相似文献   

20.
新疆哈密卡拉塔格块状硫化物矿床金银赋存状态研究   总被引:3,自引:0,他引:3  
新疆哈密红海黄土坡VMS矿床位于东天山卡拉塔格隆起带,是卡拉塔格矿集区内新发现的块状硫化物矿床。矿体产于卡拉塔格隆起带核部火山沉积岩建造中,具有典型的VMS型矿床“上层下脉”二元结构特征。该矿床中含金硫化物矿石主要有块状黄铁矿黄铜矿、块状黄铁矿黄铜矿闪锌矿、块状黄铁矿闪锌矿黄铜矿和块状闪锌矿。文中在对各类含金硫化物矿石进行详细的矿相学研究基础上,结合扫描电子显微镜与能谱仪联用技术(SEM/EDS),对硫化物样品中金、银的赋存状态进行研究。结果表明,4种块状硫化物中的主要矿物形成于多个期次,主要包括VMS成矿期(黄铁矿阶段、闪锌矿黄铜矿黝铜矿方铅矿阶段、石英重晶石阶段)、热液叠加期(石英黄铁矿黄铜矿闪锌矿方铅矿阶段)和表生期(铜蓝纤铁矿阶段)。矿区首次发现4颗金银金属互化物(银金矿、碲银矿),其较大的化学成分差异指示了热液环境由中酸性中性转变为更有利于Au、Ag迁移沉淀的偏碱性。后期的偏碱性热液对VMS成矿期形成矿物产生了交代作用,使得Au、Ag活化再富集。由于后期热液叠加改造,红海VMS型矿床中Au、Ag不仅赋存于VMS成矿期后期中低温闪锌矿黄铜矿阶段,也赋存于VMS成矿期早期中高温黄铁矿阶段,并贯穿整个热液叠加期。各含金矿物组合中除4颗金银金属互化物外Au多呈显微不可见状态,推测Au、Ag主要以原子或离子形式赋存于矿物晶格中或矿物空位处。  相似文献   

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