大洋多金属结核和深海沉积物标准物质中铂族元素的中子活化分析

采用镍锍试金预富集中子活化分析方法,测定了大洋多金属结核标准物质ＧＳＰＮ２、ＧＳＰＮ３和深海沉积物标准物质ＧＳＭＳ２、ＧＳＭＳ３中的铂族元素;根据大洋样品成分特征,对常规的镍锍试金配方和熔炼条件作了改善;计算了活化分析中的铂族元素干扰核反应,校正了Ａｕ对Ｐｔ的二级干扰;选用羰基化镍粉配料,降低了铂族元素空白值。用国家一级标准物质ＧＢＷ０７１０２作了对照分析,结果与标准值相符。     

滇东南喷流沉积块状硫化物特征与矿床成因

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,     

The Ashele Deposit: A Recently Discovered Volcanogenic Massive Sulfide Cu-Zn Deposit in Xinjiang, China

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.     

Stepwise chemical degradation of immature S-rich kerogens from Vena del Gesso (Italy)

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.     

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

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。     

四川大铜厂表生硫化物铜矿床成因探讨

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。     

Biological and environmental changes in Lake Baikal during the late Quaternary inferred from carbon, nitrogen and sulfur isotopes

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.     

临武铁砂坪锡石—硫化物矿床地质特征及找矿意义

临武铁砂坪锡石—硫化物矿床位于香花岭多金属矿田内，属断裂充填交代型脉状锡矿床。矿区有锡石—硫化物和锡石—石英脉两种类型锡矿脉，严格受中泥盆统跳马涧组碎屑岩和棋子桥组灰岩中的NE、NW向断裂控制，Ⅳ号锡石—硫化物矿脉带长约2 500 m，宽500 m，平均品位Sn 0.36 %，最高品位Sn 1.36 %。矿脉产状与容矿断裂产状一致，赋存于棋子桥组的矿体为特殊的深浅相间的条纹岩，它是一种特殊的锡矿工业类型，在湘南地区具有找锡指导意义。     

Cu-Mo-Sn-S四元系相关系

对Cu-Mo-Sn-S四元系500-640℃的相关系进行研究,并对相关的Cu-Sn-S三元系做了进一步研究与测定。实验表明,500℃时Cu-Sn-S系的稳定的三元化合物有Cu_4SnS_4、Cu_4SnS_6(或Cu_(9.75)Sn_(2.17)S_(13))、Cu_5Sn_2S_7(或Cu_(4.90)Sn_2S_(7.01))、Cu_2SnS_3和Cu_2Sn_3S_7(或Cu_2Sn_(3.26)S_(7.51))。这些三元化合物,除Cu_4SnS_4外,都与硫形成双变关系。 Cu-Mo-Sn-S四元系在500℃时相关系主要表现为MoS_2与Cu_4SnS_6、Cu_5Sn_2S_7、Cu_2SnS_3和Cu_2Sn_3S_7等各相的双变关系,以及金属与Cu_4SnS_4、Cu_5Sn_2S_7、Cu_2SnS_3和Cu_2Sn_3S_7的双变关系。 以不同起始原料,不同温度和方法合成Cu-Mo-Sn-S四元系中唯一的四元化合物——硫钼锡铜矿未获得成功。