夏塞银多金属矿床中硫化物和硫盐系列矿物特征及其意义

夏塞矿主档是大型的热液脉型银多金属矿床,通过对大量矿石光（薄）片观察和电子探针分析表明,除主要（方铅矿、富铁闪锌矿）和次要（黄铁矿、毒砂、磁黄铁矿、黄铜矿等）硫化物外,硫盐毓硫物十分发育,主要有Ｃｕ－Ｓｂ－Ａｇ硫盐（黝铜矿、含银黝铜矿和银黝铜矿）、Ｓｂ－Ａｇ硫盐（深红银矿、辉锑银矿）、Ｐｂ－Ｓｂ硫盐（脆硫锑铅矿、硫锑铅矿）和Ｂｉ－Ｐｂ硫盐（斜方辉饿铅矿）。此外,尚有少（微）量黄锡矿、锡石、自然饿和银金矿等。银的硫盐硫物和硫化物（辉银矿）乃是获得银的主要工业矿物,这些硫盐毓矿物常与硫化物伴生,多沿方铅矿、富铁闪锌矿、黄铁矿等的解理、裂隙或粒间产出,这些研究结果不仅有助于了解矿化作用过程,而且为矿床评价,组分综合利用和选冶提供重要依据。     

Ag-rich Tetrahedrite in the El Zancudo Deposit,Colombia: Occurrence,Chemical Compositions and Genetic Temperatures

Chemical compositions of tetrahedrite—Ag-rich tetrahedrite—freibergite solid solutions (Ag-rich tetrahedrite_ss) and homogenization temperatures of fluid inclusions in quartz and carbonates of seventeen samples from nine veins in the El Zancudo deposit, Antioquia, Colombia, were investigated to reveal the origin of silver in Ag-rich tetrahedrite_ss, to derive their crystallization temperatures and to examine the relationship between chemical compositions of Ag-rich tetrahedrite_ss and their crystallization temperatures. The ores consist of arsenopyrite, pyrite, sphalerite, Ag-rich tetrahedrite_ss, galena, boulangerite, andorite, owyheeite, diaphorite, jamesonite, miargyrite, bournonite, chalcopyrite, and electrum. Ag-rich tetrahedrite_ss forms about 10 volume % of the total ores and is one of the most common and widely distributed sulfosalts in this deposit. Ag-rich tetrahedrite_ss is rich in Ag (1.13 to 31.02 wt%) and Sb (22.93 to 29.82 wt%), and poor in As (0.06 to 2.43 wt%), consistent with the reported incompatibilities of Ag and As in Ag-rich tetrahedrite_ss. The Zn/(Zn + Fe)-, Ag/(Ag + Cu)- and Sb/(Sb + As + Bi)-atomic ratios exhibit some variations among the veins. Ag-rich tetrahedrite_ss with higher Ag/(Ag + Cu) ratios coexist with diaphorite, whereas those with lower ratios are not associated with this sulfosalt. Ag-rich tetrahedrite_ss in the assemblages of Ag-rich tetrahedrite_ss+ sphalerite and of Ag-rich tetrahedrite_ss+ bournonite + galena shows no Zn ↔ Fe and Cu ↔ Ag variations between core and rim, respectively, negating the possibility of solid state reaction during cooling. Ag-rich tetrahedrite_ss is thus regarded as primary phase. Homogenization temperatures of primary fluid inclusions in quartz and carbonates co-existing with Ag-rich tetrahedrite_ss define the mineralization temperatures of 134 to 263°C. Independent crystallization temperatures of Ag-rich tetrahedrite estimated based on Zn/(Zn + Fe) and Ag/(Ag + Cu) ratios of the Ag-rich tetrahedrite_ss associated with silver minerals such as miargyrite, andorite and diaphorite using Sack's thermochemical database lie in a range between 170 and ∼250°C. Both results are thus in good agreement.     

桂西那弱银金矿床矿物组合特征及银和金的赋存状态研究

广西天峨那弱银金矿床以银矿为主,共/伴生金及铅、锌、锑等金属,矿物组合在右江盆地内为首次发现。矿体受那弱背斜及其轴向断层控制,赋矿层位为中三叠统百逢组含钙质浊积岩系。矿石矿物以硫锑铅矿、铁闪锌矿、黄铁矿、毒砂和方铅矿为主;脉石矿物主要有石英、方解石、绢云母等。主要矿石矿物由早到晚的生成顺序为:毒砂→黄铁矿→铁闪锌矿→硫锑铅矿→方铅矿。单矿物化学分析显示硫锑铅矿含Ag最高,其次为闪锌矿;黄铁矿含Au相对较高。EPMA测试结果表明Ag于方铅矿中含量最高,其次为硫锑铅矿;主要矿石矿物中毒砂含Au相对较高,其余矿物中Au含量均偏低。因矿石中的铅矿物主要为硫锑铅矿,可以认为那弱银金矿床的Ag主要赋存于硫锑铅矿中,Au主要赋存于毒砂与黄铁矿中,二者均以显微-次显微状态赋存于载体矿物中。根据矿物组合及其相互交代、切割关系等特征,将矿床划分为2个成矿期共4个成矿阶段。其中,第一成矿期为金的成矿期,矿物组合为黄铁矿和毒砂,由于后期成矿作用的叠加,仅保留一个成矿阶段;第二成矿期为银铅锌成矿期,矿物组合为方铅矿-闪锌矿-硫锑铅矿;包含第二至第四共3个完整的成矿阶段。该矿床Ag、Au共生是不同期次成矿作用叠加的结果。     

广西隆安县凤凰山Ag—Pb—Zn多金属矿床银的赋存形式及银矿物特征

凤凰山Ag－Pb-Zn多金属矿床产在寒武系类复理石建造中，赋矿围岩为砂岩和页岩，矿体受北西西向的构造破碎带控制。含矿热液流体沿构造破碎带充填，形成规模较大的多金属矿床，矿床的形成具有多期多阶段的特征。银主要以银的独立矿物形式存在，和方铝矿、硫锰矿、闪锌矿、菱锰矿及黄铁矿的关系较为密切。主要的银矿物有辉锑铅银矿、深红银矿、杂辉锑银铅矿、捷辉锑银铅矿、柱硫锑铅银矿、脆银矿、辉锑银矿和银黝铜矿等。银矿物主要形成于石英-硫化物阶段和石英-碳酸盐、硫盐阶段。     

Zun-Ospa Gold Deposit,Eastern Sayan: Geology,Ore Composition,and Genesis

The paper discusses the geology of Zun-Ospa gold deposit, which is situated near the Ospino ophiolitic nappe in the southeastern part of the Eastern Sayan, and the ore composition therein. The deposit is related to the tectonic mélange zone and is characterized by distinct structural control. Three consecutive mineral assemblages formed within a temperature range of 380°–170°C: (i) native gold–quartz–pyrite, (ii) gold–quartz–polysulfide, and (iii) silver–sulfosalt. The ore was deposited from low-concentration (5.2–14.2 wt % NaCl equiv.) solutions without CO₂, with the predominance of Mg and Fe chlorides and an admixture of Na and K chlorides. The major ore minerals are pyrite, chalcopyrite, galena, and sphalerite; identified subordinate minerals are pyrrhotite, pentlandite, heazlewoodite, fahlore (tennantite, freibergite), Ni and Ag sulfosalts (ullmannite, miargyrite, polybasite, stephanite), Ag sulfides (mckinstryite, argentite); Au minerals are represented by electrum, kuestelite, and native gold of medium to low fineness. The geological, mineralogical, geochemical, and isotopic characteristics of ore indicate a metamorphic–hydrothermal genesis of mineralization related to the formation of a mélange zone in the duplex strike-slip structure. The sources of ore components are host rock complexes that have been subjected to tectonic deformations, among which rocks of an ophiolitic association predominate, along with fragments of initial hydrothermal–sedimentary ore, granitic, terrigenous, and carbonate rocks. The Late Paleozoic (352 Ma) age of mineralization corresponds to the stage of postcollision shear deformations within the entire Central Asian Foldbelt.     

胶东西北部黄埠岭金矿床两期次叠加成矿

黄埠岭金矿床位于胶东西北部招莱金矿带,产于北东向黄埠岭-凤凰山断裂的上盘,由18条大小不一的金矿脉组成。研究表明,北东向断裂控制早期中深成金矿成矿,北北东向断裂控制晚期浅成金矿成矿。早晚两期金矿化不同,早期中深成金矿以石英、黄铁矿、辉钼矿、银金矿、自然金、黄铜矿、闪锌矿和方铅矿等组合为特征,晚期浅成金矿以石英、方解石、银金矿、自然银、硫盐矿物和胶黄铁矿等组合为特征。早晚两期成矿叠加部位构成矿区内富矿段。     

Mineral and geochemical compositions,regularities of distribution,and specific formation of ore mineralization of the Rogovik gold-silver deposit (northeastern Russia)

New data on the mineral composition and the first data on the geochemical composition of ores of the Rogovik gold-silver deposit (Omsukchan ore district, northeastern Russia) have been obtained. Study of the regularities of the spatial distribution of ore mineralization shows that the deposit ores formed in two stages. Epithermal Au-Ag ores of typical poor mineral and elemental compositions were generated at the early volcanic stage. The major minerals are low-fineness native gold, electrum, acanthite, silver sulfosalts, kustelite, and pyrite. The typomorphic elemental composition of ores is as follows: Au, Ag, Sb, As, Se, and Hg. The content of S is low, mostly < 1%. Silver ores of more complex mineral and elemental compositions were produced under the impact of granitoid intrusion at the late volcanoplutonic stage. The major minerals are high-Hg kustelite and native silver, silver sulfosalts and selenides, fahlore, pyrite, chalcopyrite, galena, and sphalerite. The typomorphic elemental composition of ores is as follows: Ag, As, Sb, Se, Hg, Pb, Zn, Cu, and B. The content of S is much higher than 1%. The ores also have elevated contents of Mo, Ge, F, and LREE (La, Ce, and Nd). At the volcanoplutonic stage, polychronous Au-Ag ores formed at the sites of the coexistence of silver and epithermal gold-silver mineralization. Their specific feature is a multicomponent composition and a strong variability in chemical composition (both qualitative and quantitative). Along with the above minerals, the ores contain high-Hg gold, hessite, argyrodite, canfieldite, orthite, fluorapatite, and arsenopyrite. At the sites with strongly rejuvenated rocks, the ores are strongly enriched in Au, Ag, Hg, Cu, Pb, Zn, Ge, Se, La, Ce, Nd, S, and F and also contain Te and Bi. The hypothesis is put forward that the late silver ores belong to the Ag-complex-metal association widespread in the Omsukchan ore district. A close relationship between the ores of different types and their zonal spatial distribution have been established. In the central part of the Rogovik deposit, epithermal Au-Ag ores are widespread in the upper horizons, Ag ores are localized in the middle horizons, and rejuvenated polyassociation Au-Ag ores occur at the sites (mostly deep-seated) with ore-bearing structures of different ages.     

Mineralogy of the Boroo Gold Deposit in the North Khentei Gold Belt,Central Northern Mongolia

Mineral assemblages and chemical compositions of ore minerals from the Boroo gold deposit in the North Khentei gold belt of Mongolia were studied to characterize the gold mineralization, and to clarify crystallization processes of the ore minerals. The gold deposit consists of low‐grade disseminated and stockwork ores in granite, metasedimentary rocks and diorite dikes. Moderate to high‐grade auriferous quartz vein ores are present in the above lithological units. The ore grades of the former range from about 1 to 3 g/t, and those of the latter from 5 to 10 g/t, or more than 10 g/t Au. The main sulfide minerals in the ores are pyrite and arsenopyrite, both of which are divisible into two different stages (pyrite‐I and pyrite‐II; arsenopyrite‐I and arsenopyrite‐II). Sphalerite, galena, chalcopyrite, and tetrahedrite are minor associated minerals, with trace amounts of bournonite, boulangerite, geerite, alloclasite, native gold, and electrum. The ore minerals in the both types of ores are variable in distribution, abundance and grain size. Four modes of gold occurrence are recognized: (i) “invisible” gold in pyrite and arsenopyrite in the disseminated and stockwork ores, and in auriferous quartz vein ores; (ii) microscopic native gold, 3 to 100 µm in diameter, that occurs as fine grains or as an interstitial phase in sulfides in the disseminated and stockwork ores, and in auriferous quartz vein ores; (iii) visible native gold, up to 1 cm in diameter, in the auriferous quartz vein ores; and (iv) electrum in the auriferous quartz vein ores. The gold mineralization of the disseminated and stockwork ores consists of four stages characterized by the mineral assemblages of: (i) pyrite‐I + arsenopyrite‐I; (ii) pyrite‐II + arsenopyrite‐II; (iii) sphalerite + galena + chalcopyrite + tetrahedrite + bournonite + boulangerite + alloclasite + native gold; and (iv) native gold. In the auriferous quartz vein ores, five mineralization stages are defined by the following mineral assemblages: (i) pyrite‐I; (ii) pyrite‐II + arsenopyrite; (iii) sphalerite + galena + chalcopyrite; (iv) Ag‐rich tetrahedrite‐tennantite + bournonite + geerite + native gold; and (v) electrum. The As–Au relations in pyrite‐II and arsenopyrite suggest that gold detected as invisible gold is mostly attributed to Au⁺¹ in those minerals. By applying the arsenopyrite geothermometer to arsenopyrite‐II in the disseminated and stockwork ores, crystallization temperature and logfs₂ are estimated to be 365 to 300 °C and –7.5 to –10.1, respectively.     

Distribution Patterns of Ag in Hydrothermal Precipitates from the Okinawa Trough

The Okinawa Trough is characterized by enrichment of Ag in hydrothermal precipitates; however, the distribution of this enrichment remains poorly constrained. This study presents the results of a field-emission scanning electron microscopy and electron-microprobe analysis based mineralogical and geochemical investigation of the spatial distribution of Ag within Ag-rich sulfide samples from the Okinawa Trough. The tetrahedrite, covellite, and galena in these samples contain high concentrations of Ag(average values of 1.60, 0.78, and 0.23 wt%, respectively) and also various Ag sulfosalts. Examination of the Ag budget of these samples indicates that most of the Ag is hosted by tetrahedrite followed by galena. The Ag within tetrahedrite is incorporated by substitution into the Cu site, whereas galena becomes Ag-enriched by the coupled incorporation of monovalent Ag, Tl, and Cu, and trivalent Sb and Bi into Pb lattice sites. Tetrahedrite and galena containing higher concentrations of Sb favor increased Ag substitution. Four sets of Ag host minerals are identified with distinct ore formation temperatures. Tetrahedrite and galena concentrate the majority of Ag at medium temperatures(150–300°C). Other Ag host minerals concentrate only minor or trace amounts of Ag, including massive sphalerite, chalcopyrite, and pyrite at high temperatures(300°C), colloform pyrite and sphalerite at low temperatures(150°C), and Ag-sulfosalts at even lower temperatures(100°C).     

Gold Mineralization of the Gatsuurt Deposit in the North Khentei Gold Belt,Central Northern Mongolia

Mineral assemblages, chemical compositions of ore minerals, wall rock alteration and fluid inclusions of the Gatsuurt gold deposit in the North Khentei gold belt of Mongolia were investigated to characterize the gold mineralization, and to clarify the genetic processes of the ore minerals. The gold mineralization of the deposit occurs in separate Central and Main zones, and is characterized by three ore types: (i) low‐grade disseminated and stockwork ores; (ii) moderate‐grade quartz vein ores; and (iii) high‐grade silicified ores, with average Au contents of approximately 1, 3 and 5 g t^?1 Au, respectively. The Au‐rich quartz vein and silicified ore mineralization is surrounded by, or is included within, the disseminated and stockwork Au‐mineralization region. The main ore minerals are pyrite (pyrite‐I and pyrite‐II) and arsenopyrite (arsenopyrite‐I and arsenopyrite‐II). Moderate amounts of galena, tetrahedrite‐tennantite, sphalerite and chalcopyrite, and minor jamesonite, bournonite, boulangerite, geocronite, scheelite, geerite, native gold and zircon are associated. Abundances and grain sizes of the ore minerals are variable in ores with different host rocks. Small grains of native gold occur as fillings or at grain boundaries of pyrite, arsenopyrite, sphalerite, galena and tetrahedrite in the disseminated and stockwork ores and silicified ores, whereas visible native gold of variable size occurs in the quartz vein ores. The ore mineralization is associated with sericitic and siliceous alteration. The disseminated and stockwork mineralization is composed of four distinct stages characterized by crystallization of (i) pyrite‐I + arsenopyrite‐I, (ii) pyrite‐II + arsenopyrite‐II, (iii) galena + tetrahedrite + sphalerite + chalcopyrite + jamesonite + bournonite + scheelite, and iv) boulangerite + native gold, respectively. In the quartz vein ores, four crystallization stages are also recognized: (i) pyrite‐I, (ii) pyrite‐II + arsenopyrite + galena + Ag‐rich tetrahedrite‐tennantite + sphalerite + chalcopyrite + bournonite, (iii) geocronite + geerite + native gold, and (iv) native gold. Two mineralization stages in the silicified ores are characterized by (i) pyrite + arsenopyrite + tetrahedrite + chalcopyrite, and (ii) galena + sphalerite + native gold. Quartz in the disseminated and stockwork ores of the Main zone contains CO₂‐rich, halite‐bearing aqueous fluid inclusions with homogenization temperatures ranging from 194 to 327°C, whereas quartz in the disseminated and stockwork ores of the Central zone contains CO₂‐rich and aqueous fluid inclusions with homogenization temperatures ranging from 254 to 355°C. The textures of the ores, the mineral assemblages present, the mineralization sequences and the fluid inclusion data are consistent with orogenic classification for the Gatsuurt deposit.     

Jusa and Barsuchi Log Volcanogenic Massive Sulfide Deposits from the Southern Urals of Russia: Tectonic Setting, Structure and Mode of Formation

The Jusa and Barsuchi Log volcanogenic massive sulfide (VMS) deposits formed along a paleo island arc in the east Magnitogrosk zone of the Southern Urals between ca 398 and 390 Ma. By analogy with the VMS deposits of the west Magnitogrosk zone, they are considered to be Baimak type deposits, which are Zn‐Cu‐Ba deposits containing Au, Ag and minor Pb. Detailed mapping and textural analysis of the two deposits shows that they formed as submarine hydrothermal mounds which were subsequently destroyed on the sea floor under the influence of ocean bottom currents and slumping. Both deposits display a ratio of the length to the maximum width of the deposit >15 and are characterized by ribbon‐like layers composed mainly of bedded ore and consisting principally of altered fine clastic ore facies. The Jusa deposit appears to have formed in two stages: deposition of colloform pyrite followed by deposition of copper–zinc–lead sulfides characterized by the close association of pyrite, chalcopyrite, sphalerite, galena, tennantite, arsenopyrite, marcasite, pyrrhotite, bornite, native gold and electrum and high concentrations of gold and silver. The low metamorphic grade of the east Magnitogorsk zone accounts for the exceptional degree of preservation of these deposits.     

桂阳宝山铅锌银矿中部铅锌矿伴生银赋存特征

宝山中部沿锌矿属中低温热液充填交代型矿床，伴生银平均品位为２３３ｇ／ｔ。银的主要载体矿物为方铅矿，闪锌矿。银呈独立矿物相为主，（含）银矿物共１２种，为一系列复杂的硫盐矿物。银易于随主金属铅锌一起回收，理想回收率达９３．７７％。     

Genesis of fahlore in the Tianbaoshan lead–zinc deposit,Sichuan Province,China: a scanning electron microscopy–energy dispersive spectroscopy study

The Tianbaoshan deposit, located in the southwestern part of the Yangtze Block, is a representative Pb–Zn deposit in the Sichuan–Yunnan–Guizhou Pb–Zn metallogenic province. The Pb–Zn orebodies are hosted in the upper Sinian Dengying Formation dolostone. The predominant minerals are sphalerite, galena, pyrite, chalcopyrite, quartz, and calcite with minor arsenopyrite, fahlore, and dolomite. The deposit is characterized by relatively strong Cu mineralization. However, the relationship between Pb–Zn and Cu mineralization is unknown. We analyzed the mineralogy and composition of fahlore, chalcopyrite, arsenopyrite, sphalerite, and galena using scanning electron microscopy–energy dispersive spectroscopy, with the aim of providing new evidence for the genesis of the Pb–Zn–(Cu) ore. The results show that the Cu ore in the deposit is dominated by chalcopyrite and fahlore, both of which formed before or during the Pb–Zn ore-forming stage. The fahlore showed dramatic compositional variation and was characterized by negative correlations between Ag and Cu, and between As and Sb, suggesting substitution of Ag for Cu, and that As and Sb substitute in the same site in the fahlore lattice. Based on backscattered electron images and composition, the fahlore was divided into two types. Type I fahlore crystallized early and is characterized by enrichment of Cu and depletion in Ag and Sb. Type II fahlore formed after Type I, and is rich in Ag and poor in Cu and As. Moreover, galena and fahlore are the host minerals of Ag. The variation of valence state with As host mineral—from fahlore to arsenopyrite—indicates the metallogenic environment changed from relatively oxidizing to reducing with a high pH. In the light of Gibbs energies of reciprocal reactions and isotherms for cation exchange, the composition of the fahlore implies its ore-forming temperature was lower than 220 °C, corresponding with typical Mississippi Valley-type (MVT) deposits. Based on the geologic character and geochemical data of this deposit, we suggest that the Tianbaoshan deposit belongs to the MVT deposit category.     

Study on the Cu–As–Sb–Ag–Bi–Pb–Te Sulfosalt Minerals from the Hydrothermal System of Southwestern Hokkaido,Japan

Shin‐Otoyo, Suttsu, Teine, Date, Chitose, and Koryu are sites rich in precious and base metal Miocene–Pleistocene epithermal deposits, and located in southwestern Hokkaido, Japan. The deposits are predominantly hosted by the Green Tuff Formation of Middle Miocene age. Ore petrographic study of these deposits shows the occurrence of variable quantities of Cu–As–Sb–Ag–Bi–Pb–Te sulfosalt minerals. Determination of mineralogical and chemical compositions of the sulfosalt minerals was undertaken to elucidate the time and spatial changes of the sulfide‐sulfosalt minerals. Various types of sulfosalt minerals identified from gold–silver and base metal quartz–sulfide veins represented some sulfosalt mineralization phases, such as the Cu–Fe–Sn–S phase of mawsonite and stannite; Cu–(As,Sb)–S phase of tetrahedrite–tennantite and luzonite–famatinite series minerals; (Cu,Ag)–Bi–Pb–S phase of emplectite, pavonite, friedrichite, aikinite, and lillianite–gustavite series minerals; (Ag,Cu)–(As,Sb)–S phase of proustite–pyrargyrite and pearceite–polybasite series minerals; and Bi–Te–S phase of tetradymite and kawazulite minerals. There are some trends in the paragenetic sequence of sulfosalt mineralization in southwestern Hokkaido (in complete or partial) as follows: sulfide → Cu–Fe–Sn–S → (Cu,Ag)–Bi–Pb–S → (Bi–Te–S) → Cu–(As,Sb)–S → ([Ag,Cu]–[As,Sb]–S). The formation of sulfosalt minerals is characterized by the introduction of some elements such as Sn, Bi, and Te at an earlier stage and an increase or decrease of some elements such as As and Sb, followed by the introduction of Ag at the later stage of ore mineral paragenesis sequence. Mineral composition of the Chitose and Koryu deposits are slightly different from those of Shin‐Otoyo, Suttsu, Teine, and Date due to their lack of Sn (tin) and Bi (bismuth) mineralization. The variable concentrations and relationships are not simply with redistributed trace elements from the original sulfide minerals of chalcopyrite, pyrite, galena, and sphalerite. Some heavier elements were also introduced during the replacement reaction, which is consistent with the occurrence of their associated minerals.     

呷村银多金属块状硫化物矿床银的赋存状态

通过大量岩石、矿石光（薄）片观察鉴定、电子探针分析、首次查明呷村海相火山岩型银多金属状块硫化物矿床有硫砷铜银矿和硫砷铜矿两种硫盐矿物。研究表明，除硫化物外（主要为方铅矿、闪锌矿、黄铁矿，其次为黄铜矿，毒砂，斑铜矿，铜铜银矿，螺硫银矿，磁黄铁矿等），硫盐矿物十分发育，主要有黝铜矿、车轮矿、硫砷铜矿、硫砷铜银矿等。该矿床中的银主要在喷流-沉积成矿阶段富集。     

云南潞西上芒岗金矿红色粘土化作用及其环境效应

上芒岗卡林型金矿床的强烈红土化作用，形成了上部红色粘土型金矿体，产生了一定范围的次生地球化学异常。金矿区红色粘土剖面可分为表土带、坡积带、钙华－沼泽带、残积带、腐泥带和基岩带 。在原生卡林型金矿红土化作用过程中，黄铁矿、毒砂、辉锑矿、方铅矿、闪锌矿等硫化物矿物发生氧化作用，S、As、Sb、Pb等有有害元素将被有效释放进入地下水和红色粘土中，进而造成地下水和土壤的污染。     

内蒙古大井矿床中银矿物的研究

本文总结了内蒙古大井矿床中银矿物的类型，产出特征以及矿物命名的问题，详细描述了黝铜矿族，浓红银矿，脆银矿，自然银以及含银的铅－铋（锑）硫盐类矿物等主要银矿物的产出状态和化学成分特征，并讨论了相应的形成条件，同时指出本区银矿物主要形成于两个矿化阶段，即：早期黄铜矿－黄铁矿阶段，主要形成了黝铜矿族的含银矿物以及辉锑银矿，硫锑铜银矿等含铜的硫盐类矿物，晚期方铅矿－闪锌矿阶段，形成的银矿物种类较为繁杂，除形成黝铜矿族矿物外，多数含铅，铋的硫盐矿物以及自然银、硫化物和浓红银矿、脆银矿等无铜的简单硫盐等均是在这一阶段形成。     

Ore and Skarn Mineralogy of the Yamato Mine,Yamaguchi Prefecture,Japan, with Emphasis on Silver‐, Bismuth‐, Cobalt‐, and Tin‐bearing Sulfides

Assemblages and chemical compositions of ore minerals from the Yamato mine, Yamaguchi Prefecture, Japan, were investigated in detail to clarify its characteristics as a skarn deposit. Special attention was paid to silver‐, bismuth‐, cobalt‐, and tin‐bearing sulfide minerals and native gold at the mine, which are described here for the first time. Samples of arsenopyrite‐dominant massive ore, and garnet‐rich, clinopyroxene‐garnet‐rich, and wollastonite‐bearing skarn ores were collected from the mine dump. Arsenopyrite is the most abundant ore mineral (>80 vol.%) in the massive ore, in association with both As‐poor/free and As‐bearing pyrite. The major ore minerals in the skarn specimens are pyrite, pyrrhotite, arsenopyrite, chalcopyrite, galena, and sphalerite, along with minor argentite, Ag‐Pb‐Bi sulfate, matildite, bismuthinite, native bismuth, molybdenite, scheelite, stannite, stannoidite, cassiterite, cobaltite, gersdorffite, and Co‐rich violarite. In addition, native gold is observed in the interstices of gangue minerals. Based on the mineral assemblages and textures of the specimens examined, the major ore minerals formed in the early stage of mineralization, and the Bi‐, Ag‐, Co‐, Ni‐, As‐ and Sn‐mineralization occurred in the middle stage. Native gold was deposited in the late stage. The estimated formation temperature of the middle mineralization stage was 312±5 °C, according to iron and zinc partitioning between stannite and coexisting sphalerite. The mineralogical properties and mineralization process of the Yamato mine are consistent with those of common skarn‐ and vein‐type ore deposits associated with ilmenite‐series granitoids in the San‐yo and San‐in districts.     

Mineral Paragenesis of the Lepanto Copper and Gold and the Victoria Gold Deposits, Mankayan Mineral District, Philippines

Abstract: Mineral paragenesis of the alteration, ore and gangue minerals of the Lepanto epithermal copper‐gold deposit and the Victoria gold deposit, Mankayan Mineral District, Northern Luzon, Philippines, is discussed. The principal ore minerals of the Lepanto copper‐gold deposit are enargite and luzonite, with significant presence of tennantite‐tetrahedrite, chalcopyrite, sphalerite, galena, native gold/electrum and gold‐silver tellurides. Pervasive alteration zonations are commonly observed from silicification outward to advanced argillic then to propylitic zone. The ore mineralogy of the Lepanto copper‐gold deposit suggests high f_S2 in the early stages of mineralization corresponding to the deposition of the enargite‐luzonite‐pyrite assemblage. Subsequent decrease in the f_S2 formed the chalcopyrite‐tennantite‐pyrite assemblage. An increase in the f_S2 of the fluids with the formation of the covellite‐digenite‐telluride assemblage caused the deposition of native gold/electrum and gold‐silver tellurides. The principal ore minerals of the Victoria gold deposit are sphalerite, galena, chalcopyrite, tetrahedrite and native gold/electrum. The alteration halos are relatively narrow and in an outward sequence from the ore, silica alteration grades to illitic‐argillic alteration, which in turn grades to propylitic alteration. The Victoria gold mineralization has undergone early stages of silica supersaturation leading to quartz deposition. Vigorous boiling increased the pH of the fluids that led to the deposition of sulfides and carbonates. The consequent decrease in H₂S precipitated the gold. Gypsum and anhydrite mainly occur as overprints that cut the carbonate‐silica stages. The crosscutting and overprinting relationships of the Victoria quartz‐gold‐base metal veins on the Lepanto copper‐gold veins manifest the late introduction of near neutral pH hydrothermal fluids.     

Enrichment characteristics and its geological significance of dispersed elements within sulfide minerals from the VI ore belt in the Maoping Pb-Zn deposit,Yunnan Province,ChinaSCIEI北大核心CSCD

作为华南大面积低温成矿域的重要组成部分,川滇黔铅锌矿集区是我国重要的铅锌银等资源基地之一,同时该矿集区也是Ge、Cd、Ga和In等稀散元素的超常富集区域。毛坪矿床是该矿集区内第二大铅锌矿床,累计探明铅锌金属储量超过3Mt(Pb+Zn平均品位≥18%),锗(Ge)保有储量182t。本文以新发现的Ⅵ矿带(铅锌金属已探明储量≥60万t,Pb+Zn平均品位≥20%)为研究对象,利用LA-ICPMS对主要矿石矿物闪锌矿和黄铁矿进行了微区原位微量元素组成和Mapping分析。研究结果显示Ⅵ矿带闪锌矿普遍富集Ge(最高580×10^(-6),均值81.1×10^(-6))、Cd(最高3486×10^(-6),均值1613×10^(-6))和Ga(最高190×10^(-6),均值44.4×10^(-6));黄铁矿普遍富集Mn、As、Pb、Cu、Ag和Sb。与Ⅰ和Ⅱ号矿带闪锌矿相比,Ⅵ号矿带闪锌矿更富集Ge和Ga。闪锌矿中Fe和Pb以类质同象为主,偶见黄铁矿和方铅矿显微包体;Cu、Ge、Ag和As赋存形式主要为类质同象,替代方式为Ge^(4+)+2(Cu+,Ag+,As+)↔3Zn^(2+);Cd以类质同象方式赋存为主,替代机制为Cd^(2+)↔Zn^(2+);Ga和In可能主要以类质同象方式存在。黄铁矿中Pb和Mn主要以方铅矿和碳酸盐矿物显微包体为主;Cu、As和Sb以类质同象形式存在于黄铁矿中;Ag和Zn可能以独立矿物形式赋存;Co和Ni以类质同象方式替代Fe进入黄铁矿晶格中,替代方式为Ni^(2+)+Co^(2+)↔2Fe^(2+)。毛坪矿床新发现Ⅵ矿带硫化物相比典型MVT矿床硫化物具有不同的In和Ge含量以及Cd/Fe比值,结合矿床地质特征和其他证据,表明毛坪矿床成因类型特殊,有别于经典MVT铅锌矿床,属于川滇黔型铅锌矿床。