scholarly journals Mineralogy and genesis of the Oleninskoe gold deposit (Kola Peninsula).

2021 ◽  
Author(s):  
A. A. Kalinin ◽  
◽  
Ye. E. Savchenko ◽  
V. Yu. Prokofiev ◽  
◽  
...  
Keyword(s):  
High Salinity ◽  
Ore Deposits ◽  
Mineral Formation ◽  
Silver Alloys ◽  
Mineral Associations ◽  
Gold Silver ◽  
Ore Minerals ◽  
Alteration Processes ◽  
Native Silver ◽  
Gold Mineral

Data on geology of the Oleninskoe deposit, and results of mineralogical and geochemical investigations of ores and altered rocks are presented. Mineralization is connected with granite porphyry sills, an end member of gabbrodiorite-diorite-granodiorite complex of minor intrusions. The main alteration processes are diopsidization and biotitization, formation of quartz-muscovite-albite, quartz-aresenopyrite-tourmaline, and quartz metasomatic rocks. More than 50 ore minerals (sulfides, sulfosalts, tellurides, and native metals) were identified in the ore, including 20 minerals of silver and gold. Mineral associations in the ore and sequence of mineral formation are defined. Five generations of gold-silver alloys are identified, its composition covers spectrum from native silver to high-grade gold. Mineralized fluids in the deposit are of high salinity (sodium and calcium chlorides), and rich in As, Sb, Pb, Cu, Zn, and Ag. The Oleninskoe deposit is classified as an epithermal metamorphosed gold deposit.The book is of interest for specialists in economic geology, mineralogy and geochemistry of ore deposits.

Chemical and textural interpretation of late-stage coffinite and brannerite from the Olympic Dam IOCG-Ag-U deposit

2017 ◽  
Vol 81 (6) ◽  
pp. 1323-1366 ◽  
Author(s):  
Edeltraud Macmillan ◽  
Nigel J. Cook ◽  
Kathy Ehrig ◽  
Allan Pring
Keyword(s):  
Internal Structure ◽  
Late Stage ◽  
South Australia ◽  
Compositional Variation ◽  
Diverse Range ◽  
Mineral Associations ◽  
Gold Silver ◽  
Copper Gold ◽  
Alteration Processes ◽  
Olympic Dam

AbstractThe Olympic Dam iron-oxide copper-gold-silver-uranium deposit, South Australia, contains three dominant U minerals: uraninite; coffinite; and brannerite. Microanalytical and petrographic observations provide evidence for an interpretation in which brannerite and coffinite essentially represent the products of U mineralizing events after initial deposit formation at 1.6 Ga. Marked compositional and textural differences between the various types of brannerite and coffinite highlight the role of multiple stages of U dissolution and reprecipitation.On the basis of petrography (size, habit, textures and mineral associations) and compositional variation, brannerites are divided into four distinct groups (brannerite-A, -B, -C and -D), and coffinite into three groups (coffinite-A, -B and -C). Brannerite-A ranges in composition from what is effectively uraniferous rutile to stoichiometric brannerite, and has elevated (Mg +Mn + Na + K) and (Fe + Al) compared to other brannerite types. It displays the most diverse range of morphologies, including complex irregular-shaped aggregates, replacement bands, and discrete elongate seams. The internal structure of brannerite-A consists of randomly-oriented hair-like needles and blades. Brannerite-B (>5 μm in size) is generally prismatic and typically associated with baryte and REY minerals (REE+Y= REY). Brannerite-C and -D are both associated with Cu-(Fe)-sulfides and are typically composed of irregular masses and blebs (10–50 μm in size) with a more uniform or massive internal structure. Brannerite-D is distinct from -C and always contains inclusions of galena. Brannerite-B to -D all contain elevated ΣREY, with brannerite-B and -C having elevated As, and brannerite-D having elevated Nb.All coffinite is typically globular (each globule is 2–10 μm in size) to collomorphic in appearance. Coffinite-A ranges from discrete globules to collomorphic bands completely encompassing quartz. Coffinite-B is always found with uraninite, and includes collomorph coffinite enveloped by massive uraninite, as well as aureoles of coffinite on the margins of uraninite crystals. Coffinite-C is associated with brannerite and REY minerals. The majority of coffinite is heterogeneous.Brannerite and coffinite have probably precipitated as part of a late-stage hydrothermal U-event, which might have involved the dissolution and/or reprecipitation of earlier precipitated uraninite, or could represent the products of a later U mineralizing event. Evidence which supports formation of late-stage coffinite and brannerite includes: (1) low-Pb contents of both minerals; (2) coffinite is commonly found on the edges of uraninite, implying later deposition; and (3) coffinite is often found on the edge of brannerite aggregates, suggestive of brannerite precipitation occurred before coffinite. Moreover, there are many features (e.g. banding, scalloped edges, alteration rinds, variable compositions etc.) indicative of hydrothermal alteration processes.

scholarly journals Genetic Environments of the Eunjeok Au–Ag Deposit in the Yeongam District: Implications for Cretaceous Epithermal Au–Ag Mineralization in South Korea

Minerals ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1088
Author(s):  
Chul-Ho Heo ◽  
Seong-Yong Kim ◽  
Il-Hwan Oh
Keyword(s):  
South Korea ◽  
Fault System ◽  
Alteration Zone ◽  
Epithermal Mineralization ◽  
Gold Silver ◽  
Ore Minerals ◽  
Major Fault ◽  
Native Silver ◽  
Homogenization Temperatures ◽  
Geologic Setting

Eunjeok Au–Ag deposits are situated in the Yeongam district, Cheollanamdo-province, South Korea. They are genetically related to the Bulgugsa magmatic event (ca. 110–60 Ma), caused by the transition in the subduction direction and style of the Izanagi Plate. Three gold- and silver-bearing hydrothermal veins filled the fractures of the Cretaceous rhyolitic tuff. The major ore minerals were arsenopyrite (31.47–32.20 at.% As), pyrite, chalcopyrite, sphalerite (8.58–10.71 FeS mole%) and galena with minor amounts of electrum (62.77–78.15 at.% Au), native silver, and argentite. Sericitization was dominant in the alteration zone. The various textures of quartz veins (i.e., breccia, crustiform, comb, and vuggy) may indicate the formation of an epithermal environment. The auriferous fluids with the H2O–NaCl system have homogenization temperatures and salinities of 204 °C to 314 °C, less than 10 wt.% equiv. NaCl, and experienced mixing (dilution and cooling) events during mineralization. Considering the characteristics of the geologic setting, major fault system, and host rock, the Eunjeok Au–Ag deposit within the Yeongam district tends to share the general geologic characteristics of Haenam–Jindo epithermal mineralization episodes. However, the age of gold–silver mineralization (86.0 Ma) is older than that of Haenam–Jindo epithermal mineralization episodes (<70.3 Ma), implying some differences exist in the genetic sequence of extensional characteristics caused by transcurrent Gwangju–Yeongdong faults.

Hell and Black Smokers

Pyrite ◽  
2015 ◽  
Author(s):  
David Rickard
Keyword(s):  
Ore Deposits ◽  
Mineral Formation ◽  
Ore Genesis ◽  
The Earth ◽  
Unknown Reason ◽  
Ore Minerals ◽  
Lead Zinc ◽  
Ancient Times ◽  
Arsenic Copper ◽  
Solid Liquid

Most of the important metal ores in medieval and ancient times were pyrite-rich sulfides. These pyrite-rich ores were a major source of a suite of valuable commodities such as sulfur, arsenic, copper, lead, zinc, and nickel, as well as some gold and silver. This is why in 1725 Henckel could devote a 1,000-page volume to pyrites, sensu lato. Because of its relative abundance, its potential economic importance, and its exotic composition compared with the rock-forming minerals, pyrite has played a key role through the ages in developing ideas of how minerals and ore deposits form. During the last century, pyrite became an even more important mineral in discussions of ore genesis because it is also a key component of sediments. This led to conflicting theories of ore genesis, in which the ore minerals were formed in the sediments or introduced later, often by processes related to volcanism. The conflict between adherents of these theories continues to this day. Pyrite constituted a key, but sometimes uncomfortable, mineral in ancient theories of mineral formation. It was relatively common and often economically important. However, it contained sulfur as a key constituent and this contrasted it to many other common minerals and rocks in that this meant that pyrite could be changed by heating. Heating released sulfur from pyrite, leaving a residue of stony slag. The ancients also recognized sulfur as a special material since it occurred in solid, liquid, and gaseous form, rather like water. Any theory of mineral formation needed to explain how this protean element got into pyrite. This problem was compounded by the fact, discussed in Chapter 3, that for some unknown reason the ancients did not know that pyrite contained iron. Ancient theories of mineral formation divide into three categories: (a) the Genesis theory: that all minerals were formed by God during the creation of the Earth; (b) the Aristotelian theory: that all minerals were formed at depth in the Earth through the interactions of the four basic elements; and (c) the Alchemical theory: that minerals were formed from combinations of mercury and sulfur.

scholarly journals Silver mineralization of the deposit of Kanjol (Northern Tajikistan)

2019 ◽  
Author(s):  
Ф.А. Файзиев
Keyword(s):  
Crystal Lattice ◽  
Silver Content ◽  
Industrial Concentration ◽  
Mineral Formation ◽  
The Third ◽  
Ore Minerals ◽  
Native Silver ◽  
First Time ◽  
Silver Mineralization

В статье приводятся сведения о стадийности минерализации и даётся характеристика некоторых минералов месторождения Канджол. Отмечается, что образование минералов на месторождении происходило в 5 стадий: кварцарсенопиритовую, полиметаллическую, медносурьмяную, кварцкальцитовую с серебром и карбонатную. В ранней кварцарсенопиритовой стадии серебро встречается в очень малых количествах и составляет от 20 до 30 г/т. Во второй полиметаллической стадии серебро отлагается вместе с галенитом и находится в его кристаллической решетке в виде изоморфной примеси. В галените среднее содержание серебра равно 4240 г/т. В третью медносурьмяную стадию образуется серебросодержащий тетраэдрит с содержанием серебра 5,720,20 мас. . Концентрация серебра в сульфидах этой стадии составляет (г/т): в галенитах 2865, халькопиритах 330 и пиритах 358,7. Затем образуется наиболее продуктивная на серебро стадия кварцкальцитовая с серебром. Здесь серебро образует собственные минералы пираргирит, аргентит, полибазит, самородное серебро, матильдит. Серебряные минералы встречаются в виде мономинеральных жил, прожилков и включений. Завершает процесс минералообразования на месторождении карбонатная стадия с кварцем, баритом и рудными минералами (галенит, сфалерит). Здесь серебро в небольших количествах содержится в сульфидах. В целом, для серебра продуктивны 24 стадии минералообразования. Основное количество серебра (6070) связано с 3й стадией минерализации. В статье охарактеризованы собственно серебряные минералы пираргирит, аргентит, самородное серебро, полибазит, миаргирит, сильванит, аргентоярозит, арсенаргентит, кераргирит, матильдит, а также тетраэдрит и галенит, несущие промышленную концентрацию серебра. Матильдит на месторождении описывается впервые. The article gives information on the stages of mineralization and gives a description of some minerals from the Kanjol deposit.It is noted that the formation of minerals in the field occurred in 5 stages quartzarsenopyrite, polymetallic, copperantimony, quartzcalcite with silver and carbonate. In the early quartzarsenopyrite stage, silver is found in very small quantities and ranges from 20 to 30 g/t. In the second polymetallic stage, silver is deposited together with galena and is in its crystal lattice as an isomorphic impurity. In galena, the average silver content is 4240 g/t. In the third copperantimony stage, a silvercontaining tetrahedrite is formed with a silver content of 5.720.20 wt.. The concentration of silver in sulfides of this stage is (g/t): in galenites 2865, chalcopyrite 330 and pyrite 358,7. Then the most productive stage on silver is formed quartzcalcite with silver. Here silver forms its own minerals pyrargyrite, argentite, polybasite, native silver, matildite. Silver minerals are found in the form of monomineral veins, veinlets and inclusions. The carbonate stage with quartz, barite and ore minerals (galena, sphalerite) completes the process of mineral formation at the deposit. Here silver is found in small amounts in sulfides. In general, 24 stages of mineral formation are productive for silver. The main amount of silver (6070) is associated with the 3rd stage of mineralization. The article describes the silver minerals themselves pyrargyrite, argentite, native silver, polybasite, myargyrite, sylvanite, argentoyarosite, arsenargentite, cerargyrite, matildite, as well as tetrahedrite and galena, bearing industrial concentration of silver. Matildite on the field is described for the first time.

Effect of Gradient Energy on Diffusion in Gold‐Silver Alloys

1969 ◽  
Vol 40 (5) ◽  
pp. 2191-2198 ◽  
Author(s):  
H. E. Cook ◽  
J. E. Hilliard
Keyword(s):  
Silver Alloys ◽  
Gold Silver ◽  
Gradient Energy

scholarly journals Mineragenic Position and Geological Potential of Technogenic- Mineral Formations of the Gold-Silver Deposit Valunistoe (Сhukotka Autonomous Region)

2021 ◽  
Vol 20 (2) ◽  
pp. 172-191
Author(s):  
V.N. Goldyrev ◽  
◽  
V.A. Naumov ◽  
O.B. Naumova ◽  
◽  
...  
Keyword(s):  
Industrial Development ◽  
Mineral Resources ◽  
Silver Deposit ◽  
Mineral Formation ◽  
Secondary Mineral ◽  
Chemical Parameters ◽  
Useful Components ◽  
Gold Silver ◽  
Solid Part ◽  
Physical And Chemical

In the coming years, the mine of LLC "Rudnik Valunisty" developing the gold and silver Valunistoe and Gornoye deposits will exhaust economically justified reserves. One of the ways to extend the life of the mine and increase the profitability of production should be the extraction of man-made secondary mineral resources. The purpose of the study is to identify the main types of solid and hydromineral form of technogenic-mineral formations at the Valunistoe Deposit, as well as to estimate the possibility of their industrial development. The useful components content was determined and calculated. The results of theoretical modeling of physical and chemical parameters of hypergenic mineral formation of the solid part of technogenic-mineral formations are shown. Objects of formation of technological waters are given. The conditions of concentration of gold and other metals are considered.

scholarly journals Magmatic and Postmagmatic Mineral Associations of the Malyutka Massif Rocks (Khudolazovkiy Complex of the South Urals)

2021 ◽  
Vol 20 (2) ◽  
pp. 99-109
Author(s):  
I.R. Rakhimov ◽  
Keyword(s):  
Chemical Composition ◽  
Crystallization Temperature ◽  
Equilibrium Temperature ◽  
South Urals ◽  
The South ◽  
Accessory Minerals ◽  
Rock Formation ◽  
Genetic Interpretation ◽  
Mineral Associations ◽  
Ore Minerals

The results of detailed mineralogical studies of the Malyutka massif altered rocks of the Khudolazovskiy differentiated complex are presented. The morphology and chemical composition of many rock-forming and accessory minerals are described. According to the study, the magmatic and post-magmatic (hydrothermal-metasomatic) stages of rock formation are distinguished. The problems associated with the genetic interpretation of a number of rock-forming and ore minerals are discussed. The conclusion about the polygenic nature of the formation of spinelids is made. The equilibrium temperature in the «Ti-magnetite–ilmenite» system (633–650 °C), as well as the crystallization temperature of chlorite, replacing phlogopite and hornblende (145–185 °C), were estimated.

scholarly journals I. The liquation of gold and platinum alloys

1890 ◽  
Vol 47 (286-291) ◽  
pp. 180-186 ◽  
Keyword(s):  
Copper Alloys ◽  
Gold Alloys ◽  
Silver Alloys ◽  
Platinum Alloys ◽  
Silver Copper ◽  
Gold Silver ◽  
Almost All

It is a well known fact that when molten alloys of certain metals are cooled, some of the constituents separate and become concentrated either in the centre or in the external portions of the solidified mass; to this segregation the name of liquation is given. It is specially noticeable in the case of silver-copper alloys, and its importance is now being widely recognised in almost all branches of metallurgy. In the case of gold, however, the phenomenon of liquation does not appear to have been much observed. Gold alloys, to the value of many millions sterling, pass annually from hand to hand upon the results of assays cut from the external portions of ingots, which assays cannot, of course, be trustworthy, if the centre of the bars differs in composition from the external portions. Peligot has recently endeavoured to obtain evidence of liquation in gold-copper alloys, and has concluded that it does not exist. Roberts-Austen, who has devoted much time to the study of liquation, has also satisfied himself that gold-silver alloys do not rearrange themselves on cooling.

Accessory and Ore Mineralization of Schists from the Basement of the Yamal Peninsula (Zapadno-Yarotinsky Area, Western Siberia)

2021 ◽  
pp. 49-55
Author(s):  
Yuriy V. Erokhin ◽  
Kirill S. Ivanov ◽  
Anatoliy V. Zakharov ◽  
Vera V. Khiller
Keyword(s):  
Western Siberia ◽  
The Arctic ◽  
Yamal Peninsula ◽  
Metamorphic Rocks ◽  
The West ◽  
Temperature Range ◽  
Ore Minerals ◽  
Ore Mineralization ◽  
Native Silver ◽  
The Yamal Peninsula

The results of studying the mineralogy of metamorphic schists from the Pre-Jurassic base of the Arctic part of the West Siberian plate are presented. The accessory and ore mineralization of schists from the Zapadno-Yarotinsky license area located in the southern part of the Yamal Peninsula is studied. The schists was uncovered by the Zapadno-Yarotinskaya No. 300 well at a depth of 2762 m. Above the section, the metamorphic rocks are overlain by a young Meso-Cenozoic cover. The schists are mainly composed of quartz, plagioclase (albite), carbonates (dolomite and siderite), mica (muscovite) and chlorite (donbassite). The discovered accessory and ore minerals in the metamorphic schists of the Zapadno-Yarotinsky area can be divided into two groups. The first group includes minerals that were formed during the metamorphism of schists, or were preserved as detrital matter. These minerals include zircon, fluorapatite, and rutile as the most stable compounds. The remaining mineralization (pyrite, sphalerite, chalcopyrite, cubanite, galena, cobaltite, barite, xenotime-(Y), goyazite, synchysite-(Nd), native silver and copper) is clearly secondary and was formed as a result of superimposed metasomatic processes. Judging from the described mineralogy, the schists underwent changes as a result of superimposed propyllitization. The temperature range of this process is determined by the formation of cubanite in association with chalcopyrite at a temperature of 200-210 оС.

Geology of the Liese Zone, Pogo Property, East-Central Alaska

SEG Discovery ◽  
1999 ◽  
pp. 1-21
Author(s):  
MOIRA SMITH ◽  
JOHN F.H. THOMPSON ◽  
JASON BRESSLER ◽  
PAUL LAYER ◽  
JAMES K. MORTENSEN ◽  
...  
Keyword(s):  
Gold Deposit ◽  
Gold Mineralization ◽  
Geochemical Data ◽  
East Central ◽  
Gold Silver ◽  
Ore Minerals ◽  
Middle Paleozoic ◽  
Deposit Type ◽  
Alteration Minerals ◽  
Native Bismuth

ABSTRACT The Liese zone is a recently discovered high-grade gold deposit on the Pogo claims, approximately 90 miles (145 km) southeast of Fairbanks. A conservative geologic resource for the Liese zone is 9.98 million tons at an average grade of 0.52 oz/t, for a total of 5.2 million contained ounces. The region is underlain by highly deformed, amphibolite-grade paragneiss and minor orthogneiss of the Late Proterozoic(?) to middle Paleozoic Yukon-Tanana terrane, which has been intruded by Cretaceous felsic granitoid bodies thought to be related to gold mineralization in the Fairbanks area and elsewhere along the Tintina gold belt. The Liese zone is hosted primarily in gneiss, and lies approximately 1.5 km south of the southern margin of the Late Cretaceous Goodpaster batholith. Mineralization occurs in three or more tabular, gently dipping quartz bodies, designated L1 (uppermost), L2, and L3 (lowermost). The thickness of the quartz bodies ranges from 1 to 20 m, averaging approximately 7 m. The quartz contains approximately 3 percent ore minerals, including pyrite, pyrrhotite, loellingite, arsenopyrite, chalcopyrite, bismuthinite, various Ag-Pb-Bi ± S minerals, maldonite, native bismuth, and native gold. Early biotite and later quartz-sericite-stockwork and sericite-dolomite alteration are spatially associated with the Liese zone, which shows characteristics of both vein and replacement styles of mineralization. Geochemical data indicate a strong correlation between gold and bismuth, and weaker correlations between gold, silver, and arsenic. Based on U-Pb dating of intrusive rocks, the Liese zone was formed between 107 and 94.5 m.y. ago, although 40Ar/39Ar cooling ages on alteration minerals return younger ages of 91 Ma, suggesting a protracted or multiphase thermal history. The Liese zone may represent a deep-seated manifestation of the "intrusion-related" gold deposit type.

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