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951.
952.
滇东南喷流沉积块状硫化物特征与矿床成因 总被引:41,自引:8,他引:33
滇东南一些著名的大型-超大型锡多金属矿床,如个旧锡矿和都龙锡矿,白牛厂大型银,锡多金属矿床下部均有燕山期花岗岩发育,因此,个旧和都龙锡多金属矿床大多数人认为是岩浆热液矿床。笔者对上述三个矿床的矿石矿物组构、成分以及它们的共生组合关系进行了系统研究,发现了大量海底喷流沉积结构构造,值得一提的是在岩体接触带附近的块状硫化物矿体中发现了缅状结构和丝状客形虫等证据,而这些矿体曾被认为是典型的岩浆热液成因, 相似文献
953.
The Ashele Deposit: A Recently Discovered Volcanogenic Massive Sulfide Cu-Zn Deposit in Xinjiang, China 总被引:1,自引:0,他引:1
Abstract: The Ashele Cu-Zn deposit is a recently discovered volcanogenic massive sulfide deposit in Xinjiang, Northwestern China. It is the largest Cu-Zn deposit in this type of deposits in China, which were formed in the early period of later Palaeozoic Era. This deposit is hosted within a suit of bimodal submarine volcanic rocks of the Ashele Formation of Lower-Middle Devonian System formed in an environment of paleocontinental margin rift setting. Lensoid orebodies occur between spilitic rocks developed at footwall and quartz-keratophyric tuff at hanging wall. Zonation of metal elements in the Ashele mine is one of typical volcanic-related exhalative Cu-Zn sulfide deposits in the world. Black ores enriched in Pb, Zn and Ag occurs on the top of the No. 1 orebody in the Ashele deposit, yellow ores enriched in Cu in the middle part, and the chalcopyritization stringer below the massive sulfide ores. Zonation of ore-structure in the No. 1 orebody is also apparent and corresponds to the zoning of elements, i. e. lamellar and/or banded sulfide-sulfate ores on the top, massive sulfide ores in the middle, and stockwork veinlets associated with altered breccia pipe on the bottom. Four epochs of mineralization in the Ashele deposit has been recognized. The first period of syngenetic-exhalative deposition of sulfides is the main epoch of mineralization, and the ores deposited subsequently subjected to thermo-metamorphism at the second epoch, superimposed by hydrothermal mineralization at the third epoch, and weathered or oxidized at the fourth epoch.
More than 100 categories of minerals have been recognized in the Ashele mine, but only pyrite, chalcopyrite, sphalerite, tetrahedrite, galena, barite, quartz, chlorite, sericite, and calcite are dominant, making up various types of ores, and alteration pipes or horizons. Studies of ore petrology suggest that the massive ores were volcanogenic and deposited by exhalative process. 相似文献
More than 100 categories of minerals have been recognized in the Ashele mine, but only pyrite, chalcopyrite, sphalerite, tetrahedrite, galena, barite, quartz, chlorite, sericite, and calcite are dominant, making up various types of ores, and alteration pipes or horizons. Studies of ore petrology suggest that the massive ores were volcanogenic and deposited by exhalative process. 相似文献
954.
Jia Jianye 《中国地质大学学报(英文版)》1998,9(3):2
Surfacemineralogyisoneofthemodernbranchesofmin-eralogy.Theresearchoftheinterfaceofmineral-liquid,namelythestudyonthereactiono... 相似文献
955.
C. Schaeffer-Reiss P. Schaeffer A. Putschew J. R. Maxwell 《Organic Geochemistry》1998,29(8):1857-1873
Stepwise chemical degradation involving cleavage of ester bonds (KOH/MeOH), sulfide and remaining ester bonds (Li/EtNH2), ether bonds (HI/LiAlH4) and sub-units linked to aromatic moieties (RuO4) has been carried out on the kerogens of two immature sulfur-rich marls (IV-1.4 and 1.8, TOC ca. 1.5%) from evaporitic cycle IV of the Gesosso-solfifera Formation (Messinian, Vena del Gesso, Italy). Up to 80% of the organic matter was converted to solvent-soluble material, with the greatest proportion released by Li/EtNH2. The majority by far of the extracts comprises polar macromolecular material which is thought to correspond to high molecular weight sub-units of the kerogen. Quantification of the small amounts (<1%) of the released GC-amenable components indicates that diagenetic sulfurization was more important in the case of kerogen IV-1.4 but that the extent of oxygen sequestration was similar in both cases; the distributions of biomarkers released by ether cleavage of the desulfurized residue and polar fraction showed differences which reveal heterogeneity in the building blocks making up different macromolecular fractions. 相似文献
956.
干旱地区硫化矿床风化过程的穆斯堡尔谱特征--以青海锡铁山铅锌矿为例 总被引:5,自引:0,他引:5
测定了青海锡铁山硫化矿床氧化带矿物的室温穆斯堡尔谱,结果表明氧化带硫酸盐矿物的穆斯堡尔谱具较小的同质异能移、四级矩分裂值分布范围较大、无磁超精细分裂等特征。在已有工作的基础上,根据氧化带垂向不同位置矿物的穆斯堡尔谱特征划分出铁锰帽亚带、高铁矾类亚带(进一步划分出单峰型、双峰型和三峰型三个次亚带)、低铁矾类亚带及原生硫化物带等垂向分带,每一亚带代表特定的物化条件,反映了干旱地区硫化矿床风化过程的阶段性。 相似文献
957.
四川大铜厂表生硫化物铜矿床成因探讨 总被引:1,自引:0,他引:1
四川大铜厂铜矿床产于中生代晚白垩世红层砾岩中。铜的次生硫化物占全铜含量的93.40%。铅同位素Pb/204Pb为18.054~18.815,207Pb/204Pb为15.528~15.644,208Pb/204Pb为38.030~38.722,模式年龄出现负组成:206值。δ34S平均值黄铁矿>辉铜矿>斑铜矿,硫酸盐的δ34S值为较大正值,硫化物矿物大多为负值:有较大平衡分馏系数,说明成矿是在开放系统、低温低压、非平衡的表生条件下进行的。矿物流体包裹体细小(多数小于3μm)。成矿金属来源于小坝组红色砂岩层,硫来源于小坝组顶部膏盐层,为一表生硫化物矿床。 相似文献
958.
Biological and environmental changes in Lake Baikal during the late Quaternary inferred from carbon, nitrogen and sulfur isotopes 总被引:1,自引:0,他引:1
An 8-m continuous sediment core, approximately 250-ky-old at the bottom, from Academician Ridge in Lake Baikal, has been analyzed for the stable isotopes of carbon, nitrogen and sulfur, in order to study the paleoclimatic and paleobiological changes that occurred in the Eurasian continental interior. These isotopic changes are closely related to changes in vertical lake-water circulation between glacial and interglacial periods. Sedimentary organic carbon in cool periods is more enriched in 13C (−23.8‰ on average) than that in warm periods (−27.0‰ on average). The 13C-enrichment of organic carbon suggests a decrease of land-derived organic matter influx to the lake, less precipitation, and loss of terrestrial vegetation around Lake Baikal in cool periods. Pyrite in high total sulfur/total organic carbon (TS/TOC) layers shows strong depletion in 34S (−20.8‰ to −32.4‰) during climate transitions from glacial to interglacial periods at the beginning of oxygen isotope stages (OIS) 1, 5 and 7. The 34S-depleted pyrite indicates augmentation of dissimilatory sulfate reduction by sulfate reducing bacteria (SRB) at the sediment-water interface. Enhancement of aqueous sulfate concentrations and limitation of oxygen circulation to the surface sediments might also occur in the climate transition periods. The δ15N values of total nitrogen increase abruptly by ∼2‰ just after the δ34S negative peaks, which may result from low nutrient concentrations in the euphotic zone associated with water circulation changes in Lake Baikal. 相似文献
959.
北康盆地位于南沙地块的西南边缘,为南沙中部海域的新生代沉积盆地,具有良好的含油气潜力。近年广州海洋地质调查局在盆地六万多平方千米范围内完成了近2000km的地震测线,及相应的重力与磁力测量。本文在区域地质背景分析基础上,对盆地进行了地震地层对比和详细的地震相分析,划分了3个超层序、7个层序,对其中的5个层序进行了沉积相分析,并编制了沉积相平面图。晚始新世以前,北康盆地位于古南海西北缘,盆地西北部为陆相环境。东南部为滨-浅海环境。晚始新世-早渐新世早期,南沙地块从华南陆块裂离向南漂移,随古南海洋带的被动消减和新南海的扩张,盆地水体加深,除西北尚有陆相沉积外,主要为海相环境。早渐新世后,南沙地块与婆罗州地块拼贴,北康盆地逐渐处于浅海-半深海环境。与盆地沉积演化规律相对应,早第三纪发育的湖相和沼泽相泥岩及早中新世发育的浅海相泥岩为有利烃源岩, 同期的三角洲相砂岩、滨海相砂岩及晚中新世发育的浊积岩为主要储层,区域性盖层为晚各新世以来的 浅海-半深海相泥岩、砂质泥岩、局部性盖层有湖相泥岩、浅海相砂质泥岩、泥岩和灰质泥岩。 相似文献
960.
新疆黄山东铜镍硫化物矿床Re-Os同位素测定及其地球动力学意义 总被引:76,自引:15,他引:76
通过对黄山东铜镍硫化物矿石的Re_Os同位素测年 ,获得等时线年龄数据为 (2 82± 2 0 )Ma。该数据表明产于东天山的这套铜镍硫化物矿床及其相关的镁铁质_超镁铁质岩并非泥盆纪_早石炭世洋底的蛇绿岩建造和相关成矿系统 ,它晚于岛弧演化阶段 ,出现于碰撞后的伸展环境 ,与区内广泛发育的造山型金矿和浅成低温热液型金矿为同一时期形成。其等时线187Os/188Os初始比值为 0 .2 4± 0 .0 4 ,γOs值平均为 99,显示出在成矿过程及岩浆侵位期间有不少地壳物质混入成岩成矿系统 相似文献