Trace Element Distribution (Cu, Ga, Ge, Cd, and Fe) IN Sphalerite From the Tennessee MVT Deposits, USA, By Combined EMPA, LA-ICP-MS, Raman Spectroscopy, and Crystallography

Bonnet, Julien; Mosser‐Ruck, Régine; Caumon, Marie-Camille; Rouer, Olivier; Andre-Mayer, Anne-Sylvie; Cauzid, Jean; Peiffert, Chantal

doi:10.3749/canmin.1500104

Cited by 74 publications

(22 citation statements)

References 36 publications

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“…values, calculated from the individual elemental values from LA-ICP line scans, are given in brackets. For the Merelani sample, the mean Cu value for wurtzite is 1267 (26) ppm and that for the sphalerite region 1932(80) ppm. The mean Cd values for the Merelani wurtzite is 3582(60) ppm and for the sphalerite it is 2982(67) ppm.…”

Section: Resultsmentioning

confidence: 94%

“…O'Keefe and Hyde [19], pointed out that in compounds that only have a wurtzite form and no sphalerite analogue, such as zincite (ZnO), the cation-cation distances are close to the sum of the non-bonded radii. That is, the wurtzite form can be stabilized over the sphalerite form by cation-cation repulsions and this is consistent with wurtzite being sulfur-deficient and sphalerite cation-deficient.The minor and trace element chemistry of sphalerite has been the subject of much study, as has the structural nature of the coupled substitutions involved [20][21][22][23][24][25][26][27][28], but a similar study of wurtzite is lacking. In many of the above compositional studies the structural form of the ZnS were not confirmed by X-ray diffraction methods as sphalerite and some of the samples maybe have actually been intergrowths of polytypes.…”

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confidence: 99%

“…The minor and trace element chemistry of sphalerite has been the subject of much study, as has the structural nature of the coupled substitutions involved [20][21][22][23][24][25][26][27][28], but a similar study of wurtzite is lacking. In many of the above compositional studies the structural form of the ZnS were not confirmed by X-ray diffraction methods as sphalerite and some of the samples maybe have actually been intergrowths of polytypes.…”

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confidence: 99%

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Coupled Substitutions of Minor and Trace Elements in Co-Existing Sphalerite and Wurtzite

et al. 2020

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The nature of couple substitutions of minor and trace element chemistry of expitaxial intergrowths of wurtzite and sphalerite are reported. EPMA and laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) analyses display significant differences in the bulk chemistries of the two epitaxial intergrowth samples studied. The sample from the Animas-Chocaya Mine complex of Bolivia is Fe-rich with mean Fe levels of 4.8 wt% for wurztite-2H and 2.3 wt% for the sphalerite component, while the sample from Merelani Hills, Tanzania, is Mn-rich with mean Mn levels in wurztite-4H of 9.1 wt% and for the sphalerite component 7.9 wt% In both samples studied the wurtzite polytype is dominant over sphalerite. LA-ICP-MS line scans across the boundaries between the wurtzite and sphalerite domains within the two samples show significant variation in the trace element chemistries both between and within the two coexisting polytypes. In the Merelani Hills sample the Cu + + Ga 3+ = 2Zn 2+ substitution holds across both the wurztite and sphalerite zones, but its levels range from around 1200 ppm of each of Cu and Ga to above 2000 ppm in the sphalerite region. The 2Ag + + Sn 4+ = 3Zn 2+ coupled substitution does not occur in the material. In the Animas sample, the Cu + + Ga 3+ = 2Zn 2+ substitution does not occur, but the 2(Ag,Cu) + + Sn 4+ = 3Zn 2+ substitution holds across the sample despite the obvious growth zoning, although there is considerable variation in the Ag/Cu ratio, with Ag dominant over Cu at the base of the sample and Cu dominant at the top. The levels of 2(Ag,Cu) + + Sn 4+ = 3Zn 2+ vary greatly across the sample from around 200 ppm to 8000 ppm Sn, but the higher values occur in the sphalerite bands.Crenshaw [7] reported the transformation occurs at 1020 • C at 1 atm H 2 S, but subsequent researchers reported different inversion temperatures [8][9][10][11]. The transition temperature is reported to be lowered significantly by substitution of Fe, Mn, and Cd [12,13]. Sphalerite and wurtzite are essentially hydrothermal minerals generally forming at much lower temperatures, e.g., in Mississippi Valley-type deposits [2]. As far back as 1934, it was proposed that stabilization of the sphalerite was linked to an excess of sulfur, and wurtzite to sulfur deficiency [14]. Pankratz and King [15] published very accurate analyses of synthetic sphalerites and wurtzites showing that the M:S ratio for sphalerite of down to 0.997 and for wurtzite up to 1.002. Scott and Barnes [16] demonstrated by hydrothermal experiments that the crystallization of ZnS in either the sphalerite form or the wurtzite form was dependent on the sulfur fugacity, ƒS 2 , with the formation of the wurtzite polytypes restricted to low ƒS 2 (~10 −20 ).The major divalent impurities in ZnS, Fe, Mn, and Cd, are said to be all more soluble in wurtzite than sphalerite and, therefore, stabilize wurtzite relative to sphalerite under a given set of conditions [12,13,16]. Lepetit et al. [17] showed that the upper solubility limit of Fe in sphalerite has a str...

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confidence: 94%

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Coupled Substitutions of Minor and Trace Elements in Co-Existing Sphalerite and Wurtzite

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“…The positions of the main peak determined by the XANES calculations were the same as those of the experimental spectra: 11,106.5 eV for Ge metal, 11,107.5 eV for GeI2, 11,109 eV for renierite, and 11,112 eV for GeO2. The methods for LA-ICP-MS (Agilent Technologies, Santa Clara, UT, USA) and EMPA (Cameca, Gennevilliers, France) are described in [25]. SEM images were performed using a JEOL J7600F scanning electron microscope (SEM, JEOL, Akishima, Japan) equipped with an SDD-type EDS spectrometer coupled to an Oxford Wave WDS spectrometer.…”

Section: Methodsmentioning

confidence: 99%

“…Samples consisted of massive sphalerite in a thin section, but at a microscopic scale, they consisted of micro crystalline sphalerite. A more detailed description of the samples is available in Reference [25]. The Tennessee mining province is divided into two mining districts: Central Tennessee (CT) and East Tennessee (ET).…”

Section: Sphalerite Samplesmentioning

confidence: 99%

Characterization of Germanium Speciation in Sphalerite (ZnS) from Central and Eastern Tennessee, USA, by X-ray Absorption Spectroscopy

et al. 2017

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X-ray absorption near edge structure (XANES) spectroscopy was used on zoned sphalerites (ZnS) from two world-class Mississippi Valley Type deposits, the Central and Eastern Tennessee Mining district, USA, in order to investigate germanium oxidation states. Due to the low germanium concentrations of these samples, it was necessary to perform the X-ray absorption spectroscopy (XAS) in fluorescence mode. The overlapping of the Zn Kβ and Ge Kα emission lines meant that a high energy-resolution was required. This was achieved using crystal analysers and allowed a bandwidth of 1.3 eV to be obtained. Experimental spectra were compared to XANES calculations and three configurations of germanium incorporation into sphalerite were identified. The first two, the most prevalent, show germanium (II) and (IV) surrounded by sulphur atoms in tetrahedral coordination, suggesting the replacement of Zn by Ge. In the third configuration, germanium (IV) is surrounded by oxygen atoms. This third configuration is unexpected for a zinc sulphide mineral and it resembles that of argutite (GeO 2 ).

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Genesis of greenockite (CdS) and associated sulphide‐gold mineralization from Mahakoshal belt, Central Indian Tectonic Zone

et al. 2023

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The Zn‐Cd‐S critical minerals system is a significant mineralogical indicator of hydrothermal ore‐forming processes. The understanding of greenockite (CdS) formation in natural mineral systems is very restricted due to low crustal abundances (Cd <0.2 ppm). We report the first occurrence of greenockite from the Bagada orogenic gold prospect, Paleoproterozoic Mahakoshal belt, Central Indian Tectonic Zone (CITZ). This provides an ideal opportunity to access the occurrence and its genesis. Greenockite occurs in discrete sheared quartz veins hosted in phyllites. Sulphide mineralization is closely associated with hydrothermal chlorite alterations. Pyrrhotite, arsenopyrite, pyrite, and chalcopyrite assemblages are formed at high temperatures, while sphalerite and galena precipitated when the temperature decreased. Greenockite, native silver and bismuth with gold precipitated during the breakdown of arsenopyrite to scorodite in progressively oxidizing conditions. Greenockite precipitation occurred in a transforming hydrothermal environment from a reducing to an oxidizing one during late‐stage hydrothermal alteration. Sphalerite and chlorite thermometry yielded temperatures in the range from 266 to 366°C for this late‐stage hydrothermal alteration. Textural relations show two modes of occurrence of greenockite, one (Gck‐1) as exsolution within sphalerite (Sp‐2) and the other (Gck‐2) occurring as a discontinuous rim replacing the Cd‐rich sphalerite (Sp‐3). The Gck‐1 contains high Zn and low Cd, while as compared to Gck‐2. Zinc and Cd in greenockite show diadochy relation (Zn2+ ↔ Cd2+). Laser ablation ICPMS analyses of sphalerite (Sp‐2) reveal remarkably high Cd contents (1.9–12 wt%). Cd >0.02 ppm suggests possible Cd derivation from sphalerite (Sp‐2) under variable fS2, T, pH, fO2 conditions, fluid–rock interaction, and change in the Zn/Cd ratio. Sphalerite compositions display a low Zn/Cd (av.22) ratio and high temperature of formation, with characteristics intermediate between volcanogenic massive sulphides (VMS) and magmatic‐hydrothermal Cu‐Pb‐Zn system.

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Trace Element Distribution (Cu, Ga, Ge, Cd, and Fe) IN Sphalerite From the Tennessee MVT Deposits, USA, By Combined EMPA, LA-ICP-MS, Raman Spectroscopy, and Crystallography

Cited by 74 publications

References 36 publications

Coupled Substitutions of Minor and Trace Elements in Co-Existing Sphalerite and Wurtzite

Coupled Substitutions of Minor and Trace Elements in Co-Existing Sphalerite and Wurtzite

Characterization of Germanium Speciation in Sphalerite (ZnS) from Central and Eastern Tennessee, USA, by X-ray Absorption Spectroscopy

Genesis of greenockite (CdS) and associated sulphide‐gold mineralization from Mahakoshal belt, Central Indian Tectonic Zone

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