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Showing 1 to 20 of 20 for “"Marcasite"”.
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Relative rates of reaction of pyrite and marcasite with ferric iron at low pH
… of pulverized samples (100-200 mesh) of 3 marcasite and 7 pyrite specimens from various sources were determined at 25°C and pH = 2.0 in ferric chloride solutions with initial ferric iron concentrations of 10⁻³ molal. The rate of the reaction: FeS₂ + 14Fe³⁺ + 8H₂O = 15Fe²⁺ + 2SO₄²⁻ + 16H⁺ …
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The geochemistry of gold-bearing and gold-free pyrite and marcasite from the Getchell gold deposit, Humboldt County, Nevada
… and geochemical investigations of pyrite and marcasite from the Getchell Carlin-type gold deposit show that elevated concentrations of a characteristic suite of trace metals correlate with ore-stage pyrite morphology. Secondary ion mass spectrometry analyses revealed a significant positive …
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Photovoltaic properties and size-pH phase stability of iron disulfide from density-functional theory
… as gap states; (ii) presence of the polymorph marcasite. Based on density-functional theory (DFT) calculations, (i) the intrinsic (100) surface states are not gap states but located at the conduction band edge; (ii) epitaxial growth of marcasite on pyrite is thermodynamically favorable, but its …
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Magmatic-hydrothermal evolution of the Tuvatu alkalic epithermal Au-Telluride deposit, Viti Levu, Fiji
… microanalysis of biotite, pyrite, and marcasite to reconstruct the evolution of the magmatic-hydrothermal system and to identify the relative timing of Au mineralization. Eight vein types have been identified, including four porphyry-style veins which formed at higher temperatures and …
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Iron minerals in sedimentary phosphorites of the southeastern United States
… degree of weathering of the deposit. Pyrite and marcasite (FeS₂) are the principal iron mineral inclusions in unweathered phosphorites of Florida, North Carolina, and Tennessee, and occur as discrete, randomly disseminated microcrysts, irregularly shaped microcryst aggregates, cubes, dendrites, …
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Characterization of the Gold Hill low-sulfidation epithermal Au-Ag vein system, northern Nye County, Nevada; Implications for continued discoveries in established mining districts
… Hill as follows:- Stage I), Monomictic pyrite±marcasite breccias, with angular-subangular 2-20 cm, quartz-adularia altered clasts of tuff of Mt. Jefferson (Tmj) and varying intensities of silicification in the matrix, which includes up to 10% pyrite±marcasite (modal abundance). - Stage II), …
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A Comparison of Geochemistry, Carbonate Mineralogy, and Argillic Alteration between the Dome Prospect and the Main Au Resource of the Donlin Creek Project in Southwest Alaska
… of euhedral arsenopyrite on porous pyrite-marcasite ± pyrrhotite grain boundaries, mainly in the resource area, demonstrates the late timing of the precious-metal minerals compared to the base-metal mineral assemblage. The base-metal district is noted for …
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Petrology and mineralogy of certain portions of the Fredericktown deposits
… sequence of the sulphides is as follows: marcasite and pyrite-bravoite; siegenite and chalcopyrite I; chalcopyrite II and pyrite-bravoite; sphalerite and galena. Marcasite is the earliest and galena the latest mineral to form.</p> <p>In view of the geometric features exhibited by about 90 …
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Mineralogical, textural, and paragenetic studies of selected ore deposits of the Southeast Missouri lead-zinc-copper district and their genetic implications
… galena, sphalerite, chalcopyrite, pyrite, marcasite, dolomite, calcite, and quartz and minor siegenite, bornite, bravoite, blaubleibender covellite, covellite, gersdorffite, digenite, enargite, tennantite, dickite, and malachite.</p> <p>The paragenesis indicates that the ore solutions …
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Microbially influenced corrosion in sour environments
… was found to be a mixture of greigite and marcasite. However, this composition was observed to change irreversibly with the application of a laser that caused the material to either heat and/or dry. The resulting golden-colored corrosion product was found to consist mainly of monosulfides, …
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Precombustion desulfurization of coal by photochemical methods and pyrite depression in froth flotation
… from metal sulfide minerals such as pyrite and marcasite. The process comprises depressing the metal sulfide minerals with a reagent resulting from the alkaline oxidation and polymerization of a polyphenol or a quinone, and selectively floating clean coal from the depressed metal sulfide …
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Inorganic and organic geochemistry of the zinc ores of the Idol Mine, East Tennessee
… accompanied by minor amounts of dolomite and marcasite. A major stage of coarse white dolomite precipitation took place after sphalerite. Minor amounts of other gangue minerals including pyrite, calcite, quartz, gypsum and fluorite all postdate ore formation. Field observations complemented by …
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The timing, composition, and source of subsurface diagenetic waters responsible for sulfide and carbonate mineralization in solution cavities of the ordovician galena group limestone, North Aurora, Illinois, USA
… cavities consisting of dissolution followed by marcasite, pyrite, and calcite precipitation. The repetition of these diagenetic events and the paragenetic ordering of mineralization, in conjunction with changes in isotopic (87Sr/86Sr) and elemental concentrations (Ca, Na, Sr, Fe, Mg, and Mn) in …
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Geochemistry and origin of the Asimotrypes carbonate hosted mesothermal gold deposit, Pangeon mountain, N. Greece
… pyrrhotite, tetrahedrite-tennantite, marcasite, covellite and malachite. Gold is either refractory occurring mainly in arsenopyrite and to a lesser extent in Aspyrite, or free in the oxide minerals.<br/><br/>Three types of fluid inclusions (with subtypes) were recognised based on …
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Evidence for rapid epithermal mineralization and coeval bimodal volcanism, Bruner Au-Ag property, NV USA
… <1% pyrite/goethite + Au-Ag minerals, with trace marcasite and microscopic Fe-poor sphalerite.Property-scale K-feldspar alteration related to a pre-ore hydrothermal system is overprinted by Au-Ag stage alteration consisting of proximal quartz + Fe-sericite + pyrite ± adularia and distal …
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Time-Space Relationships between Sediment-Hosted Gold Mineralization and Intrusion-Related Polymetallic Mineralization at Kinsley Mountain, NV
… pyrite, carbonate in ore zones, and lack of marcasite, kaolinite, or dickite suggests ore fluids that were higher in temperature and less acidic than ore fluids that form the large CTGDS in Nevada. Aluminum in hornblende geobarometry, typical formation depths of tungsten skarn deposits, and …
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Mineralogy and geochemistry of the carbonaceous mudstones and coal petrogenesis of the Grootgeluk formation in the Waterberg coalfield, South Africa
… of the Grootegeluk Formation and Beaufort Group. Marcasite sometimes occurs along bedding planes and calcite is generally present as deat-filling in the coal seams. Based on their geochemistry, the Grootegeluk Formation and Beaufort Group mudstones have the same provenance, dominantly "granitic", …
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Spatial and temporal variations in the geometry and composition of the Permian Whitehill Formation South Africa
… in form of framboidal aggregates of pyrite. Marcasite in form of lags cement and nodules is also reported. A binary mixture of organic matter and phosphorites with botryoidal textures is also abundant. The upper medium to light grey calcareous-siliceous silty lenticular shale (F3-F5) contain …
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Lithium at the Thacker Pass deposit, Humboldt County, Nevada, U.S.A.
… of chlorite, hematite, secondary pyrite, and marcasite; the presence of sulfides is dependent in part upon the localized oxidation state of the ore rock. Other minerals observed in the deposit are analcime in the LGZ, K-feldspar in the HGZ, and secondary or detrital quartz throughout. HGZ …
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Patterns of Lithology, Structure, Alteration, Trace Elements, Carbonate Mineralogy, and Stable Isotopes around High-Grade Carlin-type Gold Deposits: Turquoise Ridge Deposit, Getchell District, Nevada
… in the formation of auriferous pyrite and marcasite. The presence of interlayered basalts and ferroan carbonates could be important exploration criteria in the identification of future target areas in the Getchell District and throughout Nevada. Furthermore and most importantly, careful …