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desulfidation

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Journal Article
Published: 01 October 1981
American Mineralogist (1981) 66 (9-10): 908–930.
... chemical data for the sulfide-rich schists indicate that the pyrite → pyrrhotite transition occurs by desulfidation at constant whole-rock iron contents without participation of silicate minerals. The metamorphic reaction that converts pyrite to pyrrhotite is unusual in two respects: (a) products...
Journal Article
Journal: Economic Geology
Published: 01 May 2017
Economic Geology (2017) 112 (3): 661–674.
...-to-pyrrhotite desulfidation reaction precedes or coincides with this fluid release. Since pyrite is an important metal host in metamorphic rocks, its breakdown to pyrrhotite may allow complexation of Au with liberated sulfur. Thus, the question of the temperature-pressure conditions required for pyrite...
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Journal Article
Published: 01 February 1967
Canadian Journal of Earth Sciences (1967) 4 (1): 105–153.
... the intrusive contacts, and in adjacent wallrocks, developed during the primary cooling cycle by a process of desulfidization of the Muskox magma. Sulfide transfer in these locations was controlled primarily by the temperature gradient, not by gravity settling of a separate sulphide fluid.During subsequent...
Journal Article
Published: 01 March 2023
American Mineralogist (2023) 108 (3): 614–633.
... of pre-existing primary pentlandite, and desulfidation to form low-sulfur sulfides (mainly heazlewoodite) and awaruite under extremely low f O 2 and f S 2 conditions; (2) in situ precipitation of secondary Ni-sulfides in the presence of extra sulfur as aqueous H 2 S derived from the desulfurization...
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Journal Article
Published: 01 July 2020
The Canadian Mineralogist (2020) 58 (4): 511–532.
... chemistry, as gahnite formed from sphalerite desulfidation reactions shows a range in Mn (450–2600 ppm) and restricted V/Mn values (<0.5), while gahnite interpreted to have formed from the dehydration of biotite and staurolite shows restricted Mn (<430 ppm) and a range of V/Mn values (0.75–5.5...
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Series: Reviews in Economic Geology
Published: 01 January 2018
DOI: 10.5382/rev.20.08
EISBN: 9781629491189
... and desulfidation of fluids, jasperoid textures >180° to 200°C Au/Ag ratio 0.01 to 100 Mass transfer in Carlin-style deposits Depletion of Ca, Mg, and Sr; immobile Ti, Al, and K; strong introduction of Si, Fe, S, As, Sb, Mn, Zn, Ag, and Au; lesser introduction of Cu, Pb, Te, Tl, and Hg Mineral...
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Journal Article
Journal: Economic Geology
Published: 01 December 2008
Economic Geology (2008) 103 (8): 1613–1640.
... predict the precipitation of gold mainly in the vein due to desulfidation processes. Carbon dioxide and other gases in the fluid play an important role: they limit the f O 2 to a range where elevated gold concentrations can be maintained and transported in the fluid and also have an important effect...
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Published: 01 January 2005
DOI: 10.5382/AV100.14
EISBN: 9781934969519
... sulfur. Drastic pressure fluctuations with associated fluid unmixing and/or desulfidation during water/rock interaction are the two most commonly called-upon ore precipitation mechanisms. The specific model(s) for gold ore genesis remains controversial. Although the direct syngenetic models of the 1970s...
Journal Article
Published: 01 October 2004
The Canadian Mineralogist (2004) 42 (5): 1383–1404.
... by microthermometry and Raman-microprobe analyses, do not vary in a systematic manner on the deposit scale, although the CH 4 : CO 2 ratio varied across a large range. These observations indicate that gold deposition at Mount Charlotte occurred by desulfidation of bisulfide complexes due to reaction with Fe-rich...
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Journal Article
Journal: Economic Geology
Published: 01 September 2002
Economic Geology (2002) 97 (6): 1167–1202.
... properties for aqueous bismuth complexes, indicates that highly efficient gold and native Bi deposition was predominantly in response to desulfidation and oxidation of the fluid. Chalcopyrite precipitated mainly in response to increased pH. Gold-bismuth ore in the Eldorado deposit, an oxidized and hematitic...
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Image
Histogram plot showing the distribution of the samples at their estimated p...
Published: 01 June 2024
Figure 11. Histogram plot showing the distribution of the samples at their estimated peak metamorphic temperature. ( a ) Sulfide-bearing samples (*) are defined as those which show sulfide identified in hand sample, polished mount and thin section. Fields of “desulfidation” and “chl-out” indicate
Journal Article
Journal: Economic Geology
Published: 01 July 2001
Economic Geology (2001) 96 (4): 705–721.
... displays sulfur isotope compositions of –23.5 to –8.0 per mil and –0.1 to +11.9 per mil, respectively. Sulfides from gold-bearing quartz veins have a range of –7.4 to +8.1 per mil (median ca. +2.5‰). The relatively uniform vein pyrites indicate a large, uniform sulfur source, most likely from desulfidation...
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Journal Article
Journal: Economic Geology
Published: 01 February 1991
Economic Geology (1991) 86 (1): 66–80.
... quartz range from -17.8 to -5.6 per mil in black phyllite hosts, from -6.0 to -1.3 per mil in less reduced metasedimentary rocks, and from -3.8 to +1.2 per mil in relatively oxidized igneous rocks. The regional fluid is interpreted to have driven desulfidation reactions in relatively 34 S-depleted sulfur...
Journal Article
Journal: Economic Geology
Published: 01 April 1989
Economic Geology (1989) 84 (2): 291–327.
... to pyritization of granite (fluid desulfidation and reduction), and possibly in part, in response to dolomitization and sericitization of serpentinite (fluid acidification?). Strata-bound disseminated orebodies may be expected in a variety of other host rocks with higher than average Fe/Mg ratios, where pyrite...
Journal Article
Journal: Economic Geology
Published: 01 October 1986
Economic Geology (1986) 81 (6): 1446–1463.
... by desulfidation and oxidation reactions that involve members of the system Zn-Fe-Al-Si-S-O. Experimental reversals of the simplified reaction: ZnS + FeS + 2Al 2 O 3 + O 2 = ZnAl 2 O (sub 4/) + FeAl 2 O 4 + S 2 , using hydrothermal techniques, have been obtained at 2 and 5 kb and various temperatures using Fe (sub...
Image
Composition (wt%) of the typical BMS mineral assemblage in mantle peridotit...
Published: 01 February 2019
-related desulfidation. (Color online.)
Journal Article
Published: 01 December 2016
American Mineralogist (2016) 101 (12): 2731–2737.
... © 2016 Mineralogical Society of America 2016 Desulfidation pyrite pyrrhotite visible and “invisible” gold (silver) isomorphism thermodiffusion sulfidation ennobling of Au-Ag alloys Au-Ag sulfides Pyrite is the most well-known and widespread mineral of the iron sulfides...
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Image
F ig . 14. Log f O 2   vs. log a ΣS  diagram of phases in the system Fe-O-S...
Published: 01 September 2002
the activity-composition models in Table 7 ). A desulfidation-oxidation reaction path is shown for the West Peko ore fluid, traversing from chlorite to stilpnomelane to minnesotaite stability fields. Possible conditions during Au deposition at Eldorado are also shown. Thermodynamic data for stilpnomelane from
Journal Article
Published: 01 March 2010
European Journal of Mineralogy (2010) 22 (2): 293–304.
... and intermetallic phases related to ophiolitic chromitites is both intriguing and complex and has been previously discussed ( Garuti & Zaccarini, 1997 ; Garuti et al. , 1999 ). One of the earliest stages appears to involve the desulfidation or oxidation of existing sulfides, including both primary PGM as well...
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Journal Article
Published: 01 April 2005
The Canadian Mineralogist (2005) 43 (2): 601–622.
... and sphalerite and the possibility that gahnite formed by desulfidation of sphalerite. The remaining studies of zincian spinel in Colorado have been restricted to reports of the compositions of zincian spinel at various locations. Salotti (1965) analyzed magnesian gahnite from the Cotopaxi deposit, whereas...
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