Mineralium Deposita

Journal: Mineralium Deposita

Abbreviation

Miner. Depos.

Publisher

Springer

ISSN

0026-4598
1432-1866

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Publications 1 - 10 of 34

Micron-to-nanoscale investigation of Cu-Fe-Ni sulfide inclusions within laurite (Ru, Os)S₂ from chromitites
González‐Jiménez, José María; González-Pérez, Igor; Plissart, Gaëlle; et al. (2025)
Mineralium Deposita
This paper provides a top-down nanoscale analysis of Cu-Ni-Fe sulfide inclusions in laurite from the Taitao ophiolite (Chile) and the Kevitsa mafic-ultramafic igneous intrusion (Finland). High-resolution transmission electron microscopy (HRTEM) reveal that Cu-Ni-Fe sulfide inclusions are euhedral to (sub)-anhedral (i.e., droplet-like) and form single, biphasic or polyphasic grains, made up of different polymorphs, polytypes and polysomes even within a single sulfide crystal. Tetragonal (I4− 2 d) and cubic (F− 4 3m) chalcopyrite (CuFeS2) host frequent fringes of bornite (Cu5FeS4; cubic F− 4 3m and/ or orthorhombic Pbca)±talnakhite (Cu9(Fe, Ni)8S16; cubic I− 4 3m)±pyrrhotite (Fe1−xS; monoclinic C2/c polytype 4C and orthorhombic Cmca polytype 11C)±pentlandite ((Ni, Fe)9S8; cubic Fm3m). Pentlandite hosts fringes of pyrrhotite, bornite and/or talnakhite. Laurite and Cu-Fe-Ni sulfide inclusions display coherent, semi-coherent and incoherent crystallographic orientation relationships (COR), defined by perfect edge-to-edge matching, as well as slight (2–4º) to significant (45º) lattice misfit. These COR suggest diverse mechanisms of crystal growth of Cu-Fe-Ni sulfide melt mechanically trapped by growing laurite. Meanwhile, the mutual COR within the sulfide inclusions discloses: (1) Fe-Ni-S melt solidified into MSS re-equilibrated after cooling into pyrrhotite±pentlandite, (2) Cu-Ni-Fe-S melts crystallized into the quaternary solid solution spanning the compositional range between heazlewoodite [(Ni, Fe)3±xS2] (Hzss) and ISS [(Cu1±x, Fe1±y)S2]. Additionally, nanocrystallites (50–100 nm) of Pt-S and iridarsenite (IrAsS) accompanying the sulfide inclusions spotlight the segregation of PGE-rich sulfide and arsenide melt earlier and/or contemporarily to laurite crystallization from the silicate magmas. Cobaltite (CoAsS)-gersdorffite (NiAsS) epitaxially overgrown on laurite further supports the segregation of arsenide melts at early stages of chromitite formation.
Sequential evolution of Sn–Zn–In mineralization at the skarn-hosted Hämmerlein deposit, Erzgebirge, Germany, from fluid inclusions in ore and gangue minerals
Korges, Maximilian; Weis, Philipp; Lüders, Volker; et al. (2020)
Mineralium Deposita
Fluid and source magma evolution of the Questa porphyry Mo deposit, New Mexico, USA
Klemm, Leonhard M.; Pettke, Thomas; Heinrich, Christoph A. (2008)
Mineralium Deposita
Paleoproterozoic Mississippi Valley-type mineralization at Black Angel, Greenland: evidence from sulfide δ⁶⁶Zn and rhenium-osmium geochronology
Saintilan, Nicolas J.; Archer, Corey; Szilas, Kristoffer; et al. (2025)
Mineralium Deposita
We provide timestamps for the major zinc-lead (Zn-Pb) Mississippi Valley-type Black Angel deposit (Greenland) based on new pyrite rhenium-osmium (Re-Os) isotope geochemistry data: (1) a Re-Os isochron age 1,884 ± 35 million years ago (Ma – 2σ, 1.8%) for subhedral pyrite cemented by sphalerite ± galena in dolomitized clean limestone, and, (2) a Re-Os model age 1,828 ± 16 Ma (2σ, 0.9%) for epigenetic massive pyrite in siltstone/mudstone cap rock. Zinc-lead mineralization in evaporite-bearing carbonates in the Karrat Basin took place ca. 1,884 Ma at the time of far-field fluid flow associated with back-arc spreading ca. 1,900–1,850 Ma. Mineralization predates the development of the Rinkian foreland basin (ca. 1,850 – < 1,800 Ma) and a collisional stage (ca. 1,830 – < 1,800 Ma) in the context of the telescoping Rinkian and the Nagssugtoqidian Orogens. Replacement of clean carbonate and sustained acid neutralization led to significant sphalerite precipitation ca. 1,884 Ma. Conversely, precipitation of epigenetic massive pyrite in the cap rock ca. 1,828 Ma may signal (1) the lack of chemical reactivity of the cap rock for the pH-buffered conditions needed for Zn-Pb mineralization, and (2) the unfavorable impact of incipient regional Rinkian metamorphism (ca. 1,830–1,800 Ma) and tectonic compression on aquifer permeability and continued brine migration. The initial 187Os/188Os ratio (Osi-pyrite = 1.07 ± 0.32) from isochron regression identifies a crustal origin for Os and, by corollary, other metals in the ca. 1,884 Ma Zn-Pb mineralization. Although the Rae Craton basement rocks comprise the dominant source for metals (based on our Osi-pyrite and δ66Znpyrite/sphalerite data), we identify a complementary contribution in Zn (maximum 12–24%) from Paleoproterozoic sedimentary carbonate. This source of Zn in sedimentary calcite is deemed possible in the context of Paleoproterozoic seawater at high Na/Cl ratio and in the absence of Zn-based eukaryotic metabolism in shallow marine environment.
Magma evolution and the formation of porphyry Cu-Au ore fluids
Halter, Werner E.; Heinrich, Christoph A.; Pettke, Thomas (2006)
Mineralium Deposita
Geology, mineralogy, and cassiterite geochronology of the Ayawilca Zn-Pb-Ag-In-Sn-Cu deposit, Pasco, Peru
Benites, Diego; Torró, Lisard; Vallance, Jean; et al. (2022)
Mineralium Deposita
The Ayawilca deposit in Pasco, Peru, represents the most significant recent base-metal discovery in the central Andes and one of the largest undeveloped In resources globally. As of 2018, it hosts an 11.7 Mt indicated resource grading 6.9% Zn, 0.16% Pb, 15 g/t Ag, and 84 g/t In, an additional 45.0 Mt inferred resource grading 5.6% Zn, 0.23% Pb, 17 g/t Ag, and 67 g/t In, and a separate Sn-Cu-Ag inferred resource of 14.5 Mt grading 0.63% Sn, 0.21% Cu, and 18 g/t Ag. Newly obtained U–Pb dates for cassiterite by LA-ICP-MS (22.77 ± 0.41 and 23.05 ± 2.06 Ma) assign the Ayawilca deposit to the Miocene polymetallic belt of central Peru. The polymetallic mineralization occurs as up to 70-m-thick mantos hosted by carbonate rocks of the Late Triassic to Early Jurassic Pucará Group, and subordinately, as steeply dipping veins hosted by rocks of the Pucará Group and overlying Cretaceous sandstones-siltstones of the Goyllarisquizga Group. Relicts of a distal retrograde magnesian skarn and cassiterite (stage pre-A) were identified in the deepest mantos. The volumetrically most important mineralization at Ayawilca comprises a low-sulfidation assemblage (stage A) with quartz, pyrrhotite, arsenopyrite, chalcopyrite, Fe-rich sphalerite, and traces of stannite and herzenbergite. Stage A sphalerite records progressive Fe depletion, from 33 to 10 mol% FeS, which is compatible with the observed transition from low- to a subsequent intermediate-sulfidation stage (B) marked by the crystallization of abundant pyrite and marcasite. Finally, during a later intermediate-sulfidation stage (C) sphalerite (up to 11 mol% FeS), galena, native bismuth, Cu-Pb-Ag sulfosalts, siderite, Mn-Fe carbonates, kaolinite, dickite, and sericite were deposited. This paragenetic evolution shows striking similarities with that at the Cerro de Pasco Cordilleran-type polymetallic deposit, even if at Ayawilca stage C did not reach high-sulfidation conditions. The occurrence of an early retrograde skarn assemblage suggests that the manto bodies at Ayawilca formed at the transition between distal skarn and skarn-free (Cordilleran-type) carbonate-replacement mineralization. Mineral assemblages define a T-fS2 evolutionary path close to the pyrrhotite-pyrite boundary. Buffering of hydrothermal fluids by underlying Devonian carbonaceous phyllites of the Excelsior Group imposed highly reduced conditions during stage A mineralization (logfO2 < − 30 atm). The low fO2 favored efficient Sn mobility during stages pre-A and A, in contrast to other known ore deposits in the polymetallic belt of central Peru, in which the occurrence of Sn minerals is minor. Subsequent cooling, progressive sealing of vein walls, and decreasing buffering potential of the host rocks promoted the shift from low- (stage A) to intermediate-sulfidation (stages B and C) states. LA-ICP-MS analyses reveal significant In contents in Fe-rich sphalerite (up to 1.7 wt%), stannite (up to 1908 ppm), and chalcopyrite (up to 1185 ppm). The highest In content was found in stage A sphalerite that precipitated along with chalcopyrite and stannite, thus pointing to the early, low-sulfidation assemblage as prospective for this high-tech metal in similar mineral systems. Indium was likely incorporated into the sphalerite crystal lattice via Cu+ + In3+ ↔ 2 Zn2+ and (Sn, Ge)4+ + (Ga, In)3+ + (Cu + Ag)+ ↔ 4 Zn2+ coupled substitutions. Indium incorporation mechanisms into the stannite and chalcopyrite crystal lattices remain unclear.
Silicate-replacive high sulfidation massive sulfide orebodies in a porphyry Cu-Au system: Bor, Serbia
Klimentyeva, Dina; Driesner, Thomas; von Quadt, Albrecht; et al. (2021)
Mineralium Deposita
The Cu-Au deposit of Bor (Serbia) represents a continuum of mineralization styles, from porphyry-style ore occurring in quartz-magnetite-chalcopyrite veins and chalcopyrite disseminations to high-sulfidation epithermal Cu-Au ores in pyrite-chalcopyrite and anhydrite-sulfide veins. Decisive for the great economic importance of Bor is the presence of exceptionally rich high-sulfidation massive sulfide orebodies, composed of pyrite + covellite + chalcocite/digenite and minor anhydrite and enargite. They form irregular bodies measuring 0.5-10 million tons of ore grading up to 7% Cu, hosted by andesites and surrounded by intense argillic alteration. This study focuses on a small but rich underground orebody mined out recently, where limited drillcore is preserved for quantitative geochemical study. This paper documents the vein relationships within the deep porphyry-style orebody of Borska Reka, the transitional porphyry-epithermal veins, and the overlying and laterally surrounding epithermal massive sulfides of the Bor deposit. Geological observations indicate that the formation of massive sulfide orebodies concludes the ore formation. Mass balance calculations, recast into geologically realistic bulk fluid-rock reactions, confirm textural evidence that near-isovolumetric replacement of andesite host rocks is the dominant formation mechanism of massive sulfide orebodies at Bor, whereby all lithophile elements including Si are dissolved and only Ti stays relatively immobile. While net volume changes for individual mineralization styles within the massive sulfide orebody vary from - 16% volume loss to + 127% volume gain, overall volume change for the whole massive sulfide orebody was probably slightly negative. Brecciation is important only as means of creating channelways for reactive fluid that turns the andesite protolith into massive sulfide, whereas net breccia infill occurred only locally.
Petrographic, fluid inclusion and isotopic study of the Dikulushi Cu–Ag deposit, Katanga (D.R.C.)
Haest, Maarten; Muchez, Philippe; Dewaele, Stijn; et al. (2009)
Mineralium Deposita
Tracing fluid signature and metal mobility in complex orogens: insights from Pb-Zn mineralization in the Pyrenean Axial Zone
Cugerone, Alexandre; Salvi, Stefano; Kouzmanov, Kalin; et al. (2025)
Mineralium Deposita
Orogenic processes encompass a complex interplay of deformation and metamorphic events, which can impact the formation of ore deposits to various degrees. However, distinguishing fluid signatures from orogenic versus post-orogenic events presents a significant challenge due to the scarcity of robust geochemical indicators that remain unaffected during multiple post-mineral reworking events. This study carefully examines the properties and chemistry of primary and secondary fluid inclusions (FIs), identifying distinct signatures of two fluid populations linked to different styles of Pb-Zn mineralization in the Pyrenean Axial Zone (PAZ) of Southern-France/Northern-Iberia: These included late-Carboniferous stratabound epigenetic Pb-Zn deposits and Mesozoic crosscutting Pb-Zn(-Ge) vein systems. Population (I) is identified in primary and secondary FIs in a few crosscutting Pb-Zn veins and constitutes a minor component in stratabound epigenetic bodies. It exhibits Na-dominated low to intermediate salinity (< 20 wt% NaCl eq.), intermediate temperatures (200-350 degrees C), abundant CO2-rich FIs and shows low homogeneous Cl/Br molar ratios. These characteristics are consistent with a metamorphic origin of the fluids, associated with Late-Variscan metamorphism. Population (II) is commonly observed in the crosscutting vein systems where it occurs as primary and pseudosecondary FIs, as well as in stratabound epigenetic bodies where it represents the main fluid component of secondary FIs. Population (II) is Ca-dominated with intermediate to high salinity (15-35 wt% NaCl eq.), relatively low temperature (< 200 degrees C), and shows high Cl/Br molar ratios with significant variations. This last characteristic is typical of mixing of at least two fluids, one with a probable low Cl/Br molar ratio at shallow crustal levels and another with high Cl/Br molar ratio at deeper levels. Characteristics of population (II) are consistent with a fluid of basinal origin that interacted with the basement while circulating in the Pyrenees during the Mesozoic, although a Pyrenean-Alpine age cannot be excluded. Locally, in sphalerite-hosted secondary FIs that form trails in the crosscutting veins, we find evidence of high Ge concentrations (up to few 1000s ppm), which correlate with anomalous Pb and Tl concentrations. Very high metal concentrations (up to 1-2 wt% Pb, Zn), which are inversely proportional to Cl/Br molar ratios, are found in FIs mainly within veins hosted in deep-seated high-grade metamorphic rocks. Based on a compilation of fluid data from the literature, a first-order correlation can be deduced between the metamorphic grade of the rocks hosting the mineralization and the Pb and Zn content in the FIs. Early stratabound orebodies are considered likely sources of metal for the development of the late crosscutting vein mineralization. This study demonstrates the significance and complexity of orogen-scale fluid circulation and supports the importance of pre-existing metal enrichment in the crust, especially in high-grade metamorphic rocks as a prerequisite for the formation of Pb-Zn veins in complex multi-stage orogens.
Cu – Au – Pb – Zn – Ag metallogeny of the Alpine – Balkan – Carpathian – Dinaride geodynamic province
Heinrich, Christoph A.; Neubauer, Franz (2002)
Mineralium Deposita

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