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The classification of the tetrahedrite group minerals in keeping with the current IMA-accepted nomenclature rules is discussed. Tetrahedrite isotypes are cubic, with space group symmetry I 4 ¯ 3 m. $I\overline{4}3m.$ The general structural formula of minerals belonging to this group can be written as M(2)A6M(1)(B4C2)X(3) D4S(1)Y12S(2)Z, where A = Cu+, Ag+, o (vacancy), and (Ag6)4+ clusters; B = Cu+, and Ag+; C = Zn2+, Fe2+, Hg2+, Cd2+, Mn2+, Cu2+, Cu+, and Fe3+; D = Sb3+, As3+, Bi3+, and Te4+; Y = S2– and Se2–; and Z = S2–, Se2–, and o. The occurrence of both Me+ and Me2+ cations at the M(1) site, in a 4:2 atomic ratio, is a case of valency-imposed double site-occupancy. Consequently, different combinations of B and C constituents should be regarded as separate mineral species. The tetrahedrite group is divided into five different series on the basis of the A, B, D, and Y constituents, i.e., the tetrahedrite, tennantite, freibergite, hakite, and giraudite series. The nature of the dominant C constituent (the so-called "charge-compensating constituent") is made explicit using a hyphenated suffix between parentheses. Rozhdestvenskayaite, arsenofreibergite, and goldfieldite could be the names of three other series. Eleven minerals belonging to the tetrahedrite group are considered as valid species: argentotennantite-(Zn), argentotetrahedrite-(Fe), kenoargentotetrahedrite-(Fe), giraudite-(Zn), goldfieldite, hakite-(Hg), rozhdestvenskayaite-(Zn), tennantite-(Fe), tennantite-(Zn), tetrahedrite-(Fe), and tetrahedrite-(Zn). Furthermore, annivite is formally discredited. Minerals corresponding to different end-member compositions should be approved as new mineral species by the IMA-CNMNC following the submission of regular proposals. The nomenclature and classification system of the tetrahedrite group, approved by the IMA-CNMNC, allows the full description of the chemical variability of the tetrahedrite minerals and it is able to convey important chemical information not only to mineralogists but also to ore geologists and industry professionals. [ABSTRACT FROM AUTHOR]

Graphical abstract. Highlights • Trace element incorporation into pyrite is facilitated by enrichment of antimony. • As pyrite recrystallizes, trace element contents vary based on element availability. • Retrograde cooling and annealing causes liberation of trace elements from pyrite. • Trace elements released from pyrite form sulfosalts sometimes mobilised as melts. • More than 250 tons of thallium may have been released from pyrite in some ores. Abstract Several small pyrite ± baryte ± iron-oxide orebodies (Buca della Vena, Canale della Radice, Fornovolasco, Monte Arsiccio and Pollone) are hosted in the metamorphic rocks of the southern Apuan Alps, northern Tuscany, Italy. These deposits are exceptionally thallium-rich, expressed in part by assemblages comprising rare Tl-sulfosalts. Using a variety of techniques including laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) on fifty-four samples, the textural and trace element evolution of pyrite during greenschist facies metamorphism has been described. Five generations of pyrite have been recognised. Pyrite-1 (py1) and pyrite-2 (py2) (framboidal and colloform pyrite, respectively) likely represent pristine generations and are rich in trace elements. Pyrite-3 (py3) forms fine-grained disseminations often aligned with the metamorphic fabric and likely formed during the earliest stages of deformation associated with metamorphism. Pyrite-4 (py4) forms coarse, euhedral, inclusion-rich crystal clusters and likely formed as pristine pyrite generations began to recrystallize. Pyrite-5 (py5) is typically coarse, relatively 'clean' and often euhedral. It is interpreted to be the end-product of pyrite recrystallization, with grain size increasing and micro-inclusions being expelled late on the prograde path, then granoblastic annealed textures forming during retrograde cooling. Pyrite (especially primary pyrites; py1 and py2) is particularly rich in As (up to 17,400 ppm), Sb (up to 5100 ppm) and Tl (up to 4200 ppm), while Ni, Pb and Mn may be present above 1000 ppm, and Hg, Co, Cu, Zn, Mo, Bi and Ag may all be present above 100 ppm. Some trace elements, particularly As, Ni and Co, are commonly zoned in late metamorphic pyrite overgrowths. The incorporation of some trace elements into pyrite seems to have been facilitated by the presence of Sb in a similar way that As generally facilitates Au incorporation. Concentrations of most trace elements decrease from py3 to py4 at Fornovolasco and Monte Arsiccio, while in the other deposits the opposite trend is observed. Concentrations of most trace elements drop significantly from py4 to py5, where recrystallization of pyrite liberates a large proportion of As, Sb, Tl, Pb, Hg, Cu, Zn, Ag and Mn, likely during retrograde cooling and annealing. The release of these elements from pyrite during metamorphic recrystallization has directly facilitated the formation of late-stage sulfosalts, especially at Monte Arsiccio, where textural evidence suggests sulfosalt assemblages intimately associated with py5 were mobilised as melts during greenschist facies metamorphism. At Monte Arsiccio, around 75% of Tl hosted in early recrystallized pyrite is released upon complete recrystallization. As such, mass balance calculations show that all Tl contained in Tl-sulfosalts could be supplied from locally recrystallizing pyrite, and that in total, more than 250 tons of Tl could potentially have been liberated from the pyrite orebody at Monte Arsiccio during metamorphism. This study highlights the significant quantities of Tl and other metals that may be hosted in pyrite, and also the potential role that metamorphic recrystallization may play in mobilising and (re)-concentrating (or indeed dispersing) metals in a pyrite-dominant ore system. [ABSTRACT FROM AUTHOR]

The Sangan iron skarn deposit is located in the Sabzevar-Dorouneh Magmatic Belt of northeastern Iran. The skarn contains zoned garnet, clinopyroxene and magnetite. Cores and rims of zoned garnets are generally homogeneous, having a relatively high ΣREE, low ΣLREE/ΣHREE ratios, and positive Eu anomalies. The cores of the zoned clinopyroxenes are exceptionally HREE-rich, with relatively high ΣREE and HREE/LREE ratios, as well as positive Eu anomalies. Clinopyroxene rims are LREE-rich, with relatively low ΣREE contents and HREE/LREE ratios, and do not have Eu anomalies. Magnetite grains are enriched in LREEs in comparison with the HREEs and lack Eu anomalies. Variations of fluid composition and physicochemical conditions rather than YAG-type substitution mechanism are considered to have major control on incorporating trace elements, including REE, into the skarn mineral assemblage. Based on baro-acoustic decrepitation analysis, the calc-silicate and magnetite dominant stages were formed at similar temperatures, around 350–400 °C. In the Sangan skarns, hydrothermal fluids shifted from near-neutral pH, reduced conditions with relatively high ΣREE, low LREE/HREE ratios, and U-rich characteristics towards acidic, oxidized conditions with relatively low ΣREE, high LREE/HREE ratios, and U-poor characteristics. [ABSTRACT FROM AUTHOR]

Minerals of the tetrahedrite isotypic series are widespread components of base metal ores, where they co-exist with common base metal sulphides (BMS) such as sphalerite, galena, and chalcopyrite. We used electron probe microanalysis and laser-ablation inductively-coupled plasma mass spectrometry to obtain quantitative multi-trace element data on tetrahedrite-tennantite in a suite of 37 samples from different deposits with the objective of understanding which trace elements can be incorporated, at what levels of concentration, and how the presence of tetrahedrite-tennantite influences patterns of trace element partitioning in base metal ores. Apart from Fe and Zn, Hg and Pb are the two most abundant divalent cations present in the analysed tetrahedrite-tennantite (up to 10.6 wt % Hg and 4 wt % Pb). Cadmium, Co and Mn are also often present at concentrations exceeding 1000 ppm. Apart from one particularly Te-rich tetrahedrite, most contained very little Te (around 1 ppm), irrespective of prevailing assemblage. Bismuth is a common minor component of tetrahedrite-tennantite (commonly > 1000 ppm). Tetrahedrite-tennantite typically hosts between 0.1 and 1000 ppm Se, while Sn concentrations are typically between 0.01 and 100 ppm. Concentrations of Ni, Ga, Mo, In, Au, and Tl are rarely, if ever, greater than 10 ppm in tetrahedrite-tennantite and measured W concentrations are consistently <1 ppm. Taking into account the trace element concentrations in co-crystallizing BMS, the results presented allow the partitioning trends between co-crystallized sphalerite, galena, chalcopyrite, and tetrahedrite-tennantite to be defined. In co-crystallizing BMS assemblages, tetrahedrite-tennantite will always be the primary host of Ag, Fe, Cu, Zn, As, and Sb, and will be the secondary host of Cd, Hg, and Bi. In contrast, tetrahedrite-tennantite is a poor host for the critical metals Ga, In, and Sn, all of which prefer to partition to co-crystallizing BMS. This study shows that tetrahedrite-tennantite is a significant carrier of a range of trace elements at concentrations measurable using contemporary instrumentation. This should be recognized when establishing protocols for trace element analysis of tetrahedrite-tennantite, and when assessing the main hosts of trace elements in any given assemblage, e.g., for geometallurgical purposes. [ABSTRACT FROM AUTHOR]

There is an abundance of published trace element data for sphalerite, galena and chalcopyrite in natural systems, yet for a co-crystallized assemblage comprising these base metal sulphides, there is no detailed understanding of the preferred host of many trace elements. Laser-ablation inductively-coupled plasma mass spectrometry trace element maps and spot analyses were generated on 17 assemblages containing co-crystallized sphalerite and/or galena and/or chalcopyrite from 9 different ore deposits. These deposits are representative of different ore types, geologic environments and physiochemical conditions of ore formation, as well as superimposed syn-metamorphic remobilisation and recrystallization. The primary factors that control the preferred base metal sulphide host of Mn, Fe, Co, Cu, Zn, Ga, As, Se, Ag, Cd, In, Sb, Te, Tl and Bi are element oxidation state, ionic radius of the substituting element, element availability and the maximum trace element budget that a given sulphide mineral can accommodate. Temperature, pressure, redox conditions at time of crystallization and metal source, do not generally appear to influence the preferred base metal sulphide host of all the trace elements. Exceptions are Ga, In and Sn recrystallized at high metamorphic grades, when the preferred host of Ga and Sn usually becomes chalcopyrite. In more typical lower temperature ores, the preferred host of Ga is sphalerite. Indium concentrations also increase in chalcopyrite during recrystallization. At lower temperatures the partitioning behaviour of Sn remains poorly constrained and shows little predictable pattern among the data here. The results obtained may be used as a tool to assess co-crystallization. If trace element distributions in a given base metal sulphide assemblage match those reported here, and assuming those distributions have not been significantly altered post (re-) crystallization, then it may be suggestive of a co-crystallized assemblage. Such information provides a foundation for novel attempts to develop trace element-in-sulphide geothermometers. [ABSTRACT FROM AUTHOR]

Minor and trace elements can substitute into the crystal lattice of galena at various concentrations. In situ LA-ICP-MS analysis and trace element mapping of a range of galena specimens from different deposit types are used to obtain minor/trace element data, aimed at achieving insight into factors that control minor/trace element partitioning. The previously recognized coupled substitution Ag++(Bi,Sb)3+ ↔ 2Pb2+ is confirmed. However, the poorer correlation between Ag and (Bi+Sb) when the latter elements are present at high concentrations (~>2000 ppm), suggests that site vacancies may come into play: [2(Bi,Sb)3++ ↔ 3Pb2+]. Galena is the primary host of Tl in all mapped mineral assemblages. Along with Cu, Tl is likely incorporated into galena via the coupled substitution: (Ag,Cu,Tl)++(Bi,Sb)3+ ↔ 2Pb2+. Tin can reach significant concentrations in galena (>500 ppm). Cd and minor Hg can be incorporated into galena; the simple isovalent substitution (Cd,Hg)2+ ↔ Pb2+ is inferred. This paper shows for the first time, oscillatory and sector compositional zoning of minor/trace elements (Ag, Sb, Bi, Se, Te, Tl) in galena from two epithermal ores. Zoning is attributed to slow crystal growth into open spaces within the vein at relatively low temperatures. The present data show that galena can host a broader range of elements than previously recognized. For many measured elements, the data sets generated display predictable partitioning patterns between galena and coexisting minerals, which may be dependent on temperature or other factors. Trace element concentrations in galena and their grain-scale distributions may also have potential in the identification of spatial and/or temporal trends within individual metallogenic belts, and as markers of ore formation processes in deposits that have undergone superimposed metamorphism and deformation. Galena trace element geochemistry may also display potential to be used as a trace/minor element vector approach in mineral exploration, notably for recognition of proximal-to-distal trends within a given ore system. [ABSTRACT FROM AUTHOR]