Helium and argon isotope trace in ore-forming fluid of Sawuer gold belt in Xinjiang,China

The helium and argon isotope compositions of fluid inclusions hosted in pyrite have been measured from Kuoerzhenkuola and Buerkesidai gold deposits in Sawuer gold belt, northern Xinjiang. The results show that fluidinclusion ^3He/^4He ratios are 0.64 Ra-4.25 Ra and 1.16 Ra-9.48 Ra, ^40Ar/^36Ar ratios are 282-359 and 312-525 for Kuoerzhenkuola and Buerkesidai gold deposits respectively.The ore-forming fluids of two deposits possessed the same source and derived mainly from mantle beneath the island arc (including oceanic crust and oceanic sediments by subduction of oceanic plate). They were diluted by incorporating meteoric water to form a mixture of mantle- and partial meteoric water-derived fluid. The ore-forming fluids of twodeposits are of the same evolutionary histories. From the early to the late mineralization stages, the ratios of meteoric water/mantle- derived fluid in ore-forming fluid increasedgrad ually. Based on these results and detailed geological and geochemical studies on the two deposits, it is proposed that the geneses of the two gold deposits are the same, being volcanogenic late-stage hydrothermal gold deposits occurring in the same volcanic apparatus.     

淋湘金矿地球化学特征

陕西旬阳淋湘金矿床产于南秦岭古生界泥盆系地层中,容矿围岩主要为碳酸盐岩和细碎屑岩,金矿体主要受近东西向断裂控制．第Ⅱ、第Ⅲ矿化阶段为金的主要矿化阶段,第Ⅱ～Ⅲ阶段石英包体中N2含量大于21μg/g,而第Ⅳ阶段矿物中的N2含量均小于1μg/g,说明成矿流体中的N2含量减少对金矿化不利;成矿流体的氢氧同位素组成与变质水相当;矿石的硫同位素早期为18.21‰,中晚期为17.83‰～14.01‰;铅具有正常铅同位素特征;不同矿化程度的矿石的稀土元素组成的球粒陨石标准化分配曲线,呈富轻稀土的右倾型,曲线形态基本一致,随着矿化增强其稀土元素含量明显增高．这些矿床地球化学特征表明,成矿金属元素和硫主要来源于造山带围岩地层,属容矿岩石为沉积岩中的浅层渗滤同生热盐水型金矿床,成矿时代为燕山期．     

Dual origins of Xiaoqinling gold-bearing quartz veins: Fluid inclusion evidence

Fluid inclusion research in Archean metamorphic rocks, Yanshanian granite and gold-bearing quartz veins shows that regional metamorphic fluids are high temperature and high saline, Yanshanian post-granitic fluids are CO₂-bearing low saline, and ore-forming fluids are also CO₂-rich low saline. In gold-barren/free parts of quartz veins in gold deposits, daughter mineral-bearing high saline inclusions retated with metamorphic fluids remained. This proclaims quartz veins hosting gold ores might have been formed in early metamorphism, and overlapped or mineralized by late Yanshanian gold-bearing fluids.     

超大型矿床研究中某些问题的讨论及找矿

超大型矿床，一般指单个矿床中规模达超大型者。若将矿田内多个矿床，合称超大型矿床，则与矿床和矿田定义不符，应研究统一术语。超大型矿床划分标准，应便于全球对比和简单易行。提出一个以Ｐ．Ｌａｚｎｉｃｋａ和涂光炽的划分标准为基础的综合方案，在统一标准以前供同行研究时参考。超大型矿床分布形式，分点式、带式及首领式。后者为找矿重点。关于超大型矿床成矿流体特征、控矿因素和找矿问题，以某些金矿为例作了初步研究。未发现任何独特的成矿流体。这类矿床的形成受多因素控制，具多因复成矿床特点。综合运用多种找矿方法与手段，但有侧重，是适宜的。     

一种方解石化学成分标型方法及其在胶东金银矿中的应用

方解石是金矿中广泛发育的矿物之一,和金矿化关系密切.通过提出一种方解石化学成分标型参数δCa O-δCO2,成功应用于胶东金银矿中.对胶东各金矿和十里铺银矿中成矿期方解石的化学成分特征进行详细研究,结果表明:胶东岩浆热液型金矿及银矿中方解石的化学成分特征存在显著分区特征,金矿方解石的投点位于富CO2区域内,但银矿方解石的投点位于富Ca O区域内,以上金、银矿方解石的化学成分差异源于它们成矿环境的差异.     

深源CO2及其对金的富集成矿作用

目的深源CO2与金成矿作用关系的研究是当前地学界倍受关注的前沿课题,介绍了深源CO2的特点。方法以国内外一些典型金矿研究资料为基础,结合我们近年从事矿床地球化学研究的成果,为深源CO2与金矿化间的联系提供了直接的地质证据。结果地球深部CO2储量巨大,且处于超临界状态,对金矿化有重要作用。结论深源CO2对金矿化的作用主要表现为运输成矿物质和提供巨大的能量两个方面。     

A ubiquitous thermoacidophilic archaeon from deep-sea hydrothermal vents

Deep-sea hydrothermal vents are important in global biogeochemical cycles, providing biological oases at the sea floor that are supported by the thermal and chemical flux from the Earth's interior. As hot, acidic and reduced hydrothermal fluids mix with cold, alkaline and oxygenated sea water, minerals precipitate to form porous sulphide-sulphate deposits. These structures provide microhabitats for a diversity of prokaryotes that exploit the geochemical and physical gradients in this dynamic ecosystem. It has been proposed that fluid pH in the actively venting sulphide structures is generally low (pH < 4.5), yet no extreme thermoacidophile has been isolated from vent deposits. Culture-independent surveys based on ribosomal RNA genes from deep-sea hydrothermal deposits have identified a widespread euryarchaeotal lineage, DHVE2 (deep-sea hydrothermal vent euryarchaeotic 2). Despite the ubiquity and apparent deep-sea endemism of DHVE2, cultivation of this group has been unsuccessful and thus its metabolism remains a mystery. Here we report the isolation and cultivation of a member of the DHVE2 group, which is an obligate thermoacidophilic sulphur- or iron-reducing heterotroph capable of growing from pH 3.3 to 5.8 and between 55 and 75 degrees C. In addition, we demonstrate that this isolate constitutes up to 15% of the archaeal population, providing evidence that thermoacidophiles may be key players in the sulphur and iron cycling at deep-sea vents.     

湘东北地区脉型金矿床的活化转移

通过综合分析湘东北地区冷家溪群中金的分布规律、矿石和围岩的稀土元素及同位素地球化学特征等，论证了湘东北地区的脉型金矿床是分散在冷家溪群中的金在冷家溪群的构造－热改造演化过程中活化转移而成的，长距离的活化转移主要发生在武陵－加里东期，在印支－燕山期又发生了再活化转移，活化和再活化转移都是通过流体来进行的．     

贵州省锦屏县八克金矿流体包裹体地球化学研究

贵州省锦屏县八克金矿流体包裹体以原生包裹体为主,少量次生包裹体。包裹体大小在2-10μm之间,个别大于10μm;以含CO2三相包裹体为主,其次气液两相包裹体,少量纯CO2包裹体;成矿流体包裹体的均一温度集中在240℃-300℃,气液两相包裹体平均盐度4.29 wt%NaC l-6.51 wt%NaC l,密度为0.75 g/cm3-0.92 g/cm3,三相包裹体平均盐度:1.91 wt%NaC l-5.11 wt%NaC l,密度为0.62 g/cm3-0.97 g/cm3,得出结论是八克金矿属于低盐度低密度的中温矿床。     

川西北马脑壳金矿床载金矿物特征及其成因意义

四川西北部九寨沟县的马脑壳金矿床的主要载金矿物有黄铁矿、毒砂、辉锑矿、雄黄和褐铁矿。有两种不同类型的黄铁矿 ,分别形成于沉积成岩期和热液成矿期。前者具草莓状结构 ,后者以环带结构为特征。粒度小晶形不规则的黄铁矿具有较高的含金量 ,而晶形完整和晶粒较大者含金量相对较低。辉锑矿和雄黄以细粒浸染状分布者含金量高 ,而以块状产出者金含量低甚至不含金。褐铁矿为表生氧化作用的产物 ,含有显微 -超显微单质金。对马脑壳金矿床载金矿物的研究表明 ,矿床形成于三个成矿期 ,即沉积 -成岩期、热液成矿期、表生氧化期 ,三个成矿期之间具有内在的联系。热液成矿期含矿流体的演化具有阶段性特征 ,流体的物理化学性质迅速变化有利于金的沉淀富集     

伊犁阿希矿化角砾岩筒型金矿床

伊犁阿希金矿产于陆相火山岩一次火山岩中，受火山机构控制．深部火山热液承继性自多次复活的环型断裂上升，通过降压－沸腾－爆破－角砾岩化，形成以角砾胶结型矿石为主的矿化角砾岩筒型矿床。矿床规模大，品位高，矿化集中，属火山－次火山低温热液矿化角砾岩筒型矿床。     

黔东南某些含金石英脉成矿流体中的短链羧酸

用离子色谱法测定了黔东南某些石英脉型金矿床的石英流体包裹体浸取液中的短链羧酸和无机组分,发现其中含有甲酸盐、乙酸盐和少量草酸盐,且C (甲酸盐)>C (乙酸盐)。所研究的石英中包裹体的均一温度高于200℃。一元羧酸盐可能是中-高温成矿流体中的重要组分。     

Mechanism of inversion metallogeny of quartz vein type gold deposits in the Xiaoqinling region

There are a lot of important gold_bearing quartz veins in the Xiaoqinling metamorphic core complex. The quartz veins are strictly controlled by shear zones. Stress analysis indicates that the metallizing process of the Xiaoqinling gold deposits of quartz vein type can be divided into two stages. At the first stage, the shear zones were formed in an extensional environment, and the temperature was higher and the buried depth was greater; at the second stage, the brittle thrusts were superimposed in ductile shear zones after the tectonic stress field turned from the extension to compression. The ore_bearing fluids were concentrated in these weak positions, and the gold deposits of quartz vein type were developed.     

401矿区铀矿床地质地球化学特征及其地下堆浸评价

40 1矿区贫铀花岗岩成岩后经过三期水溶液流体的改造作用 :早期高温热液的碱交代作用使花岗岩中的铀活化转移 ,此活性铀是形成铀矿床的物质基础 ;中期中低温热液是沿断裂上升的深源富 CO2 流体与大气降水的混合产物 ,它浸出了花岗岩中的活性铀 ,并迁移至有利的断裂构造部位 ,富集成脉状热液铀矿床 ;晚期地表水沿控矿断裂向下渗滤 ,铀矿床遭受表生淋滤 ,其矿石的物理化学性质发生改变 ,为地下堆浸创造了有利条件     

准噶尔北缘典型金矿床的稀土元素地球化学特征

准噶尔北缘存在浅成低温热液型金矿床、韧性剪切带蚀变糜棱岩型金矿床及浅成岩-构造蚀变岩型金矿床等主要矿化类型．通过分析比较这些主要矿化类型金矿的REE资料,建立了各典型金矿床的REE配分模式,探讨了各矿化类型金矿床之间的REE地球化学行为差异及其与成矿的关系．结果表明,就成矿作用而言,浅成岩-构造蚀变岩型金矿床比较简单,韧性剪切带蚀变糜棱岩型金矿床较复杂,浅成低温热液型金矿最复杂．     

Mesoporous iron oxide-silica supported gold catalysts for low-temperature CO oxidation

Mesoporous iron oxide-silica composite with a high silica content was synthesized by hydrothermal method, and another composite material with a high iron content was obtained by etching part of silica in alkaline solution. Gold catalysts were loaded onto both composites by a deposition-precipitation method, and used for CO oxidation. The samples were characterized by Brumauer- Emmet-Teller （BET）, X-ray diffraction （XRD）, X-ray photoelectron spectra （XPS）, transmission electron micro- scope （TEM） and scanning electron microscope （SEM） techniques. Both composites had high specific surface areas and were amorphous. The Au nanoparticles dispersed on the surface of the composites existed in metallic state. Composite with high silica content was not suitable for Au loading, and its supported gold catalyst showed poor per- formance in catalytic reaction. In contrast, composite with high iron content allowed efficient Au loading, and CO could be oxidized completely at low temperature on its supported gold catalyst. The effects of deposition-precipi- tation pH values on Au loading and activity of the catalyst were investigated, and the results indicated that Au loading was the highest and the catalyst was the most active for CO oxidation when the synthesis pH was adjusted to 8.     

哀牢山金矿带深源流体及其成矿作用

深源流体是一种源于深部的高温高压流体，它富含Ｃｌ－、ＣＯ２、Ｓ２－等矿化剂。金矿床的形成过程是：深源流体从深部沿高渗透断裂带向上运移过程中，从含金岩体中活化出金而形成含金流体。在含金热流体中，Ａｕ主要以ＡｕＣｌ－２、ＡｕＣｌ－４、ＡｕＳ－２、ＡｕＳ－３、ＡｕＳＯ３－３等形式迁移。当含金流体进入有利的成矿环境中，与围岩发生强烈的交代作用。在交代过程中，金的络合物分解，从而导致金矿床的形成     

滇西蛇街—紫金山复背斜锑汞金砷多金属矿带成矿条件的热力学分析

本文在对滇西蛇街——紫金山复背斜锑、汞、金、砷多金属矿带地质特征研究的基础上,测定了各矿形成时的包裹体均一温度和压力。作者根据不同的蚀变粘土矿物和矿物共生组合,对锑、汞、金、砷分别成矿的物理化学条件(T、P、PH、fo_2。、fs_2。、fco_2等)进行了热力学计算。结果表明:各矿形成的物理化学条件是不相同的,并且呈现规律的变化趋势,从而造成了锑、汞、金、砷的分异,在蛇街——紫金山复背斜上形成规律的纵向带状分布。这对滇西的找矿工作和锑、汞、金、砷共生分异机理的理论研究均有一定的参考价值。     

稳定同位素在金矿床成矿研究中的应用

利用稳定同位素的方法研究金矿床的形成机制是有效的途径。通过对金厂峪金矿床的稳定同位素研究,阐明金和热液的来源,并确定出主要的成矿时间     

Analysis of rare-earth elements in fluid inclusions by inductively coupled plasma-mass spectrometry (ICP-MS)

Inductively coupled plasma-mass spectrometry (ICP-MS) is used to determine rare-earth elements abundances in fluid inclusions. Quartz separates from the Lannigou and Yata Carlin-type gold deposits, southwestern China, were prepared by the decrepitation-leach method. Leachates were analyzed by ICP-MS, using conventional sample introduction. The results demonstrate that the decrepitation-leach method, in combination with ICP-MS analysis of leachates, is effective for REE determination. The chondrite-normalized REE patterns of inclusion fluids for the Lannigou and Yata samples associated with gold mineralization are characterized by light rare-earth elements (LREE) enrichment, with a weak negative Ce anomaly and a positive or negative Eu anomaly, whereas the pattern for the Lannigou sample associated with late gold mineralization (quartz-calcite stage) is characterized by LREE enrichment relative to HREE, with negative Ce and Eu anomalies.