PGE和金的热液共生富集机制初探

本文初步探讨了热液条件下铂族元素和金生共生富集的控制因素，包括配合物迁移形式和沉淀物理化学条件的相似性；此外，铂族元素和金的固溶作用、相对溶解度、源区特征、热液性质和活动历史也有不可忽视的影响。有关结论在一定程度上丰富和深化了对铂族元素热液成矿规律的认识。     

PGE和金的热液共生富集机制初探

本文初步探讨了热液条件下铂族元素和金共生富集的控制因素,包括配合物迁移形式和沉淀物理化学条件的相似性;此外,铂族元素和金的固溶作用、相对溶解度、源区特征、热液性质和活动历史也有不可忽视的影响。有关结论在一定程度上丰富和深化了对铂族元素热液成矿规律的认识。     

人造气液包裹体方法及其在研究热液性质中的应用

人造气液包裹体方法在研究热液的物理化学性质方面较传统方法简便、易行。它可用于研究热液的等容线、不混溶性质及矿物在热液中的溶解度。本文解释了人造气液包裹体的合成方法和人造气液包裹体方法的原理,分述了应用此方法研究热液所取得的最新成果。此法不仅能用于研究热液的性质,也能用于其它方面的研究,具有广阔的前景。     

超临界流体中MoO3与WO3溶解度实验探讨

超临界地质流体以其独特的性质对金属成矿元素具有超强的萃取、层析和搬运能力,在热液矿床成矿机制研究中对揭示成矿物质的源、流和汇起着特殊和重要作用。本文利用分析纯H2MoO4在高温下脱水制备了MoO3(白色斜方晶系),在冷封式高压釜中实验测定了417℃超临界条件下,MoO3在纯水中的溶解度分别为7.3(29MPa)、14.2(45MPa)、21.6(55MPa)、27.7(78MPa)、32.5(100MPa)、和34.2(150MPa)mmol/l,热液中钼的存在形式为H2MoO4。依据前人的实验方案,补充测定了WO3在4.0%NaCl水溶液中于450%条件下的溶解度,其值分别为27.51(50MPa)和30.52(100MPa)mmol/l。结合前人研究结果发现,MoO3、WO3的溶解度在临界区域内具有超临界现象,在超临界条件下其溶解度与石英的超临界溶解度行为基本相似,表现为溶解度随体系温度和压力的升高而增大,这对揭示岩浆热液型和石英脉型钨、钼矿床的形成机制具有重要指导作用。     

热液中铅、锌、银共生分异的热力学探讨

通过元素基本性质的对比以及热力学计算分析，探讨了热液中银、铅、锌的共生分异机制。在酸性至近中性条件下，氯配合物是它们在热液中的存在形式，其中锌氯配合物最稳定；在近中性到碱性条件下，硫氢配合物占主导地位，此时，银硫氢配合物相对最稳定。温度下降、[Cr]降低、pH升高及f(O2)降低，引起银、铅、锌配合物溶解度减小，发生沉淀分离；对于硫氢配合物，其稳定性主要受pH及还原硫浓度的影响。因此，配合物的不同存在形式以及配合物稳定性之间的差异，使得它们对热液条件的改变做出不同的响应，从而导致了热液中银、铅、锌在成矿过程中的共生分异。     

热液矿床水相变控矿理论初探

在综合水物理化学性质、热液矿床、溶解度实验研究等资料的基础上,曾提出热液矿床水相变控矿理论框架.在此进一步完善该理论:①当水发生相变时可引起热容、水中矿质溶解度、压缩系数、膨胀系数等物理化学性质突变,特别是在临界点处二级相变时还出现"临界奇异性"、部分参数趋于无穷大,与水在非相变区物理化学性质的小幅度渐变区剐明显,必将...     

有机酸与贵金属相互作用实验研究进展

有机质在贵金属的表生和低温热液迁移过程中扮演了重要角色。实验研究证实有机酸与贵金属的相互作用机制包括配合和还原两种对立的反应。贵金属与有机基团和杂原子的配合能力按Ｓ》Ｎ〉ＯＨ》ＣＯＯＨ的顺序依次降低，该稳定性趋势对贵金属的有机配合物迁移条件和机理具决定性影响，而胶体迁移则是有机酸将贵金属无机配合物还原的结果。     

300℃.500bar条件下赤铁矿＋磁铁矿缓冲组合在NaCl水溶液中的溶解度

于300℃、500bar条件下用Dickson金袋式热液装置测定了赤铁矿+磁铁矿组合在0.1和1.0mol/kg NaCl水溶液中的溶解度。计算了NaCl热液中赤铁矿+磁铁矿组合的溶解度,并与实验结果对比。酸性NaCl热液中铁可能主要成Fe~(2+)存在,中—碱性条件下铁的存在形式尚需进一步研究。     

4．0％NaCl水溶液临界区域内白钨矿溶解度实验测定

溶解度的临界异常现象是超临界流体萃取技术的理论基础,目前在食品、化工等领域已得到广泛应用,但在地质领域的应用相对较少。在地质流体临界区域内金属矿物溶解度的变化行为尚需实验查明。本文在34MPa 恒压、250℃～470℃条件下和420℃恒温、压力为20～50MP 条件下分别在快速淬火高压釜中实验测定了化学试剂白钨矿在4.0%NaCl 水溶液中的溶解度。4.0%NaCl 水溶液的临界温度和临界压力分别约为411℃和31.4MPa。在34MPa 恒压条件下,白钨矿的溶解度随体系温度的升高而缓慢增大,但在体系临界温度附近突然出现极大值现象。在34MPa 恒压和温度在250℃～400℃区间内白钨矿与 WO_3在4.0%NaCl 水溶液中的溶解度(单位为 mmol/L)基本相同,这表明溶解态钨在热液流体中的存在形式可能相同。在420℃恒温条件下,白钨矿的溶解度随体系压力的升高而增大,在体系临界压力附近可能出现涨落现象,有待进一步实验查证。在4.0%NaCl 水溶液临界区域内,白钨矿的溶解度对体系温度和压力的变化反应敏感,表明白钨矿的溶解度在热液流体临界区域内具有临界异常现象。结合前人研究结果发现,白钨矿、石英、WO_3、MoO_3等物质在热液流体中的溶解度变化行为基本相似,即溶解度随体系温度和压力的升高而增大,在临界区域内出现临界异常现象。矿物溶解度的临界异常现象对揭示热液型钨矿床成矿物质的萃取、迁移和沉淀富集机制具有重要意义。     

新疆喀拉通克铜镍矿床伴生贵金属成矿地球化学研究所

按侵位顺序早分为岩浆熔离型，深熔入型和热液叠加热矿作用，其中后二者与贵金属的 及成矿关系最为密切，尤其是热液作用。贵金属Ａｕ，Ａｇ，Ｐｔ，Ｐｄ主要在热液成矿液体分异形成的高铜块状矿体中富集；含矿岩浆在岩浆主心中深熔的时间与各成因类型矿体侵位是反序的；Ｃｕ，Ｎｉ及贵金属矿是经济源熔离和脉动式多次放作用形成的。     

贵金属配分模式及地质应用

通过与ＲＥＥ模式对比，介绍了贵金属配分模式的构筑方法和组成参数；并对包括地幔岩石、科马提岩和玄武岩在内的各种基性、超基性岩石的特性ＰＧＥ＋Ａｕ配分模式和贵金属分馏机制进行了综述。     

Study of Noble Metal Elements in Lower Cambrian Black Rock Series of Guizhou-Hunan Provinces, China

ＩＮＴＲＯＤＵＣＴＩＯＮＬｏｗｅｒＣａｍｂｒｉａｎｂｌａｃｋｒｏｃｋｓｅｒｉｅｓｅｘｉｓｔｓｂｒｏａｄｌｙｉｎｍｏｒｅｔｈａｎ１０ｐｒｏｖｉｎｃｅｓｉｎＳｏｕｔｈＣｈｉｎａ（Ｃｈｅｎｅｔａｌ．,１９９０）．Ｔｈｅｂｏｔｏｍｏｆｔｈｅｓｅｒｉｅｓｓｐｏ...     

湖南西北部黑色岩系中的贵金属矿化

湖南西北部寒武系下统木昌组黑色岩系中蕴藏着丰富的镍钼钒多金属矿床及其伴生的贵金属矿化。可划分为２类岩性序列，分别赋存着镍钼－金银矿化和钒－银矿化。有机成矿作用对该类矿床（化）的形成起了主导作用。本区具有潜在的贵金属矿化的找矿前景     

Noble metals in ash-cinder wastes of the Far East thermal power plants

The distribution and speciation of gold and platinum in ash-cinder wastes of the thermal power plants of Khabarovsk krai and Primorye are considered in terms of the research methods and the results obtained. The Au and PGE contents attain 2 g/t and higher, being 0.8–1.5 g/t on average. The ash of brown coal from the Pavlovka, Khurmuli, and some other fields is characterized by elevated PGE contents. The causes of discrepancies in the analytical determination of noble metals in coaly and carbonaceous rocks are considered. Accumulation of noble metals in coal is caused largely by their sorption on carbonaceous matter. The content of noble metals in ash-cinder wastes depends on their grade in the burnt coal. The latter, in turn, depends on the metallogenic characteristics of the coalfield. Gold and platinum are of economic importance, and a special technology for their recovery should to be worked out.     

Noble metals in the insoluble carbonaceous substance of black shales and ores: Direct atomic emission data

The way of extraction of insoluble carbonaceous substance (ICS) from black shales and technique of determination of noble metals (NM) in it by direct arc atomic emission analysis (AEA) were developed. The first results are reported on the determination of mineral-bound noble metals in ICS concentrates, which were extracted from the rocks and ores of the Sukhoi Log, Vernyi, Vasil’evskoe, Kuranakh, Daugyztau, Bakyrchik, Kamennoe, El’dorado, and other deposits.     

Distribution of Cenozoic Metalliferous Coal Deposits in the Zeya–Bureya Sedimentary Basin (Eastern Siberia): Tectonic Reconstruction and Paleogeographical Analysis

Geotectonics - The study has analyzed the distribution of noble metals, rare metals, and rare earth elements in Paleocene and Lower–Middle Miocene coals of the Zeya–Bureya sedimentary...     

Distribution and formation conditions of noble metal mineralization in coal-bearing basins

Original data and a survey of the literature indicate that Au and Au-PGE mineralization are abundant in coal measures. Anomalous contents of noble metals have been established in basins with various types of basement, composed of granite, volcanic rocks, schist, and limestone. These basins are located in Au-and PGE-bearing ore districts, as well as at a considerable distance from known ore deposits and occurrences. Ore formation in coal-bearing basins may occur during sedimentation, peat accumulation, and diagenesis of organic matter or may be epigenetic. Noble metals are supplied to sedimentary basins as minerals that are transported by water and air and as ion species migrating along with surface and subsurface in-and exfiltration solutions of various chemical and genetic types. Ore mineralization concentrates in coal seams and host sedimentary beds of various grain size, including conglomerate, sand, and clay, as well as in zones of hydrothermal alteration superimposed on basement rocks and the sedimentary cover. The mode of occurrence of noble metals in coal basins is diverse as well (noble metal minerals, isomorphic admixtures in sulfides, and organic compounds). The data presented allow coal-bearing basins to be regarded as promising for economic noble metal mineralization fit for recovery as by-products in the course of coal mining.     

Anthropogenic noble-metal enrichment of topsoil in the Monchegorsk area, Kola Peninsula, northwest Russia

Eight catchments, an area of 15 to 35 km², have been studied within an ecogeochemical mapping programme in the western Kola Peninsula and contiguous parts of Finland and Norway. Three catchments, one northeast of Zapolyarniy (1) and two, 5 and 25 km south of Monchegorsk (2 and 4) show high levels of deposition of heavy metals, especially nickel (Ni) and copper (Cu), related to the metallurgical industry in these cities. Twenty-five topsoil samples, from sites evenly distributed over catchment 2, have mean contents of Ni and Cu 1 to 2 orders of magnitude higher than both C-horizon samples from the same sites and topsoil samples from catchment 4, providing strong evidence for the anthropogenic origin of the heavy metals. The same samples show geometric mean total contents for the noble metals analysed of: 1.4 μg/kg rhodium (Rh), 49.6 μg/kg platinum (Pt), 187.6 μg/kg palladium (Pd) and 9.5 μg/kg gold (Au). The pattern of concentration of the noble metals mirrors that found in published averages for ore from the Talnakh mineralizations in the Noril'sk province, though 1–2 orders of magnitude lower. This also clearly shows that the noble-metal contents of the topsoil are anthropogenic, and suggests that they emanate from the plants in Monchegorsk at an early stage in treatment of the ore, probably as a minor component of Ni-Cu rich particles. The noble-metal geochemistry of the topsoil in the other catchments also reflects the nature of the ore being processed at the plants nearby.     

Native gold in Ti-bearing placers of the Ariadna cluster and its bedrock sources (Primorye region)

Centuries of intense mining of noble metals from placers of the southern Far East has exhausted their reserves. The prospects for increasing the raw material base of the region are connected with complex exogenic deposits, where noble metals play a subordinate role. The study of native gold from Ti-bearing placers spatially and genetically associated with the Ariadna mafic-ultramafic massif located on the right side of the Bol’shaya Ussurka River reveals the placer-forming role of polygenic and polychronous bedrock sources. Mafic-ultramafic rocks yielded cupriferous and mercuric gold; quartz veins with Au-As mineralization likely serve as another source of placers.     

Fluidolites as a Source of Primary Gold–Platinum Mineralization in the Poperechnoe Deposit (Malyi Khingan Range,Russia)

A genetic relationship is shown for the noble-metal mineralization (up to 11.3 g/t of Pt and platinoids and 2.58 g/t of Au) discovered in the Poperechnoe Fe–Mn deposit and the fluid–explosive breccias. The composition of platinoid minerals is in agreement with the characteristics of ore and placer formations of the Ural–Alaskan type and corresponds to the isoferroplatinum–osmium igneous paragenesis. The noble metals were crystallized at the conditions that should take place at the crust–mantle boundary under partial melting of the slab rocks. The near-surface occurrence of these metals is caused by the rising of high-mobile fluid flows. The data obtained testify to the expedience of searches for noble metals associated with occurrences of fluidolites.