Mineralium Deposita最新文献

{"title":"Olivine compositions reveal an andesitic parent magma for the Archean palladium-mineralized Lac des Iles Complex of Ontario, Canada","authors":"W. D. Smith, L. Fay, J. E. Mungall, M. Shahabi Far, L. Djon","doi":"10.1007/s00126-024-01257-4","DOIUrl":"https://doi.org/10.1007/s00126-024-01257-4","url":null,"abstract":"<p>Feldspathic lherzolite and harzburgite are reported here for the first time in the southern Lac des Iles Complex; an ~ 2.69-Ga arcuate mafic intrusion that hosts world-class Pd mineralization within varitextured and brecciated gabbronoritic rocks. The olivine-bearing rocks (Mg#_75.9–80.8) are medium- to coarse-grained, weakly to strongly serpentinized, and bordered by variably altered norite. They possess relatively high Al₂O₃ contents (4.8–10.3 wt.%), pronounced negative Nb/Nb* (0.07–0.25) values, flat to shallow negatively sloping REE profiles (La/Yb_N 1.3–4.4), and variable Eu/Eu* (0.4–1.6) values. Weakly altered samples comprise subhedral olivine (Fo_78.6–81.8) with polymineralic melt inclusions and peritectic orthopyroxene rims, cumulus orthopyroxene, sub-poikilitic clinopyroxene, as well as plastically deformed and clustered plagioclase crystals. With increasing degrees of alteration, olivine is variably serpentinized or pseudomorphically replaced by an assemblage of talc, carbonate, magnetite, and Fe-sulfides. Sparsely disseminated pentlandite-chalcopyrite-pyrrhotite (± sphalerite) blebs with platinum-group minerals (zvyagintsevite, kotulskite, and sperrylite) are rare and commonly partially replaced by magnetite. Nickel concentrations are primarily controlled by olivine (1900–4200 ppm Ni), as supported by a positive correlation between whole-rock MgO and Ni contents. Sulfur, Cu, Pd, and Pt show positive correlations and Pd/Pt values range from 2.6 to 6.7. The whole-rock and mineral compositions can be replicated through the modeling of batch crystallization of a hydrous andesitic magma that has interacted with antecedent feldspathic cumulates. The parent magma was likely at or close to sulfide saturation upon emplacement and may have co-existed with a volatile-rich phase. The Lac des Iles Complex may serve as a type example of Archean continental arc-related magmatic sulfide deposits, fed by fertile andesitic parent magmas formed through the differentiation of primitive sub-arc mantle melts in the juvenile crust.</p>","PeriodicalId":18682,"journal":{"name":"Mineralium Deposita","volume":"25 1","pages":""},"PeriodicalIF":4.8,"publicationDate":"2024-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140919581","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Peritectic orthopyroxene entrainment during partial melting of garnet peridotite produced the Bushveld Complex chromite deposits","authors":"Tahnee Otto, Gary Stevens, Jean-François Moyen, Matthew J Mayne, John D Clemens","doi":"10.1007/s00126-024-01277-0","DOIUrl":"https://doi.org/10.1007/s00126-024-01277-0","url":null,"abstract":"<p>One of the largest chromium deposits on Earth occurs in the Rustenburg Layered Suite (RLS) of the Bushveld Complex as laterally continuous chromitite layers. None of the hypotheses proposed for the origin of the chromitites can explain both the abundance of Cr in the RLS and the unusual enrichment in Cr and V over Ni, relative to typical depleted mantle values. This study investigates the possibility that the layering and chromitite formation are consequences of the entrainment of source components into the magmas that formed the RLS. Thermodynamic modelling results reveal a wedge-shaped domain in pressure-temperature space in the subcratonic mantle within which Cr-bearing orthopyroxene forms as a peritectic product of incongruent melting. Entrainment of this orthopyroxene produces magmas that crystallise peritectic olivine and chromite on ascent, due to the consumption of orthopyroxene by melt. The chromite- and olivine-bearing magmas intrude as sills and can produce chromite and dunite layers by density separation. This model, which interprets the RLS Sr-isotopic composition to reflect prior mantle metasomatism by crustal fluids (ideally ancient and of low volume), readily explains the formation of chromitite layers from relatively thin sills, as well as the very high ratios of Cr and V to other compatible elements relative to typical mantle compositions. The special circumstances required to produce the RLS chromitites do not relate to some oddity of repetitive crustal assimilation or magma compositions that allow chromite-only saturation. Rather, they relate to speed of melting and magma extraction which enabled peritectic orthopyroxene entrainment to the magmas.</p>","PeriodicalId":18682,"journal":{"name":"Mineralium Deposita","volume":"2014 1","pages":""},"PeriodicalIF":4.8,"publicationDate":"2024-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140919483","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The role of hydrothermal processes and the formation of the J-M reef and associated rocks of olivine-bearing zone I of the Stillwater Complex, Montana","authors":"A. R. Gupta, Alan E. Boudreau","doi":"10.1007/s00126-024-01267-2","DOIUrl":"https://doi.org/10.1007/s00126-024-01267-2","url":null,"abstract":"<p>Several lines of evidence, including hydrous melt inclusions and unusually Cl-rich apatite, have been used to suggest that the reappearance of olivine and PGE-sulfide of the J-M Reef in the Stillwater Complex, Montana, is due to fluid infiltration and hydration melting. This study builds upon the hydration melting model using the programs MELTS and PELE with Stillwater bulk rock compositions for the original protolith. Cl-bearing phases are not modeled by MELTS and thus simple oxide mixtures of either a pure H₂O or a H₂O + Na₂O “faux brine” are added to norite, gabbronorite, and melanorite protoliths at 1050 °C at 2 kbar pressure, conditions for which the nominally “dry” protolith is &gt; 95% solid. Incongruent hydration melting results in up to 37% olivine produced in the melanorite. The olivine Fo content is a function of the partial melt retained on cooling, and ranges between 76 and 86, overlapping the natural range of olivine compositions observed in the rocks. Modeling with the PELE program, which includes a silicate liquid Cl component, sulfur species, and a more complex C-O–H-S fluid, suggests that, for CO₂-rich fluids, fluid metal concentrations on the order of 25 ppm Pt, 75 ppm Pd, 0.03 wt.% Cu, and 0.20 wt.% Ni at a fluid/rock mass ratio of ~ 0.25 are needed to account for the observed ore grades. Sulfide and ore metals are readily remobilized for more H₂O-rich fluids, consistent with heterogeneous distribution of sulfide and regionally variable ore grades.</p>","PeriodicalId":18682,"journal":{"name":"Mineralium Deposita","volume":"52 1","pages":""},"PeriodicalIF":4.8,"publicationDate":"2024-05-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140881241","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Fluid evolution of the Lindero porphyry gold deposit, NW Argentina: the critical role of salt melts in ore formation","authors":"Valeria Simόn, Peter Koděra, Volker Lüders, Robert B. Trumbull, Marcelo Arnosio, Emilce Bustos, Louis Desanois, Marta Sośnicka, Cora Wohlgemuth-Ueberwasser","doi":"10.1007/s00126-024-01275-2","DOIUrl":"https://doi.org/10.1007/s00126-024-01275-2","url":null,"abstract":"<p>The Lindero deposit is located in the Puna plateau, northwest Argentina, at the southern end of the Central Volcanic Zone of the Central Andes. The high-K calc-alkaline dioritic composition of the subvolcanic intrusions, the shallow emplacement depth (&lt; 1.5 km), and the gold-rich and copper-depleted mineralization style suggest that the Lindero deposit is a porphyry gold deposit. Porphyry gold deposits are scarce worldwide and the factors controlling their formation are still poorly known. Here we present a detailed study of fluid inclusions in order to characterize the mineralizing fluids that precipitated the Au mineralization at Lindero. Different types of fluid inclusions in quartz veins (A-type and banded quartz), which are associated with the K-silicate alteration, were analyzed using Raman spectroscopy, microthermometry, and LA-ICP-MS (laser ablation inductively coupled plasma mass spectrometry). Four inclusion types can be recognized in quartz veins: (i) Salt melt inclusions, which are characterized by a dense packing of daughter minerals (mainly Fe-chloride, sylvite, halite, anhydrite, and hematite), by a distorted vapor bubble, and by the lack of liquid phase; (ii) Halite-bearing inclusions which contain liquid, vapor, and halite; (iii) Two-phase aqueous inclusions that contain liquid and vapor; (iv) Vapor-rich inclusions containing only vapor. The inclusion types are related to different stages of hydrothermal evolution. Stage 1 is the main mineralization stage, characterized by vapor-rich inclusions coexisting with salt melt inclusions. Salt melt inclusions commonly show total homogenization temperature (Th_L) &gt; 1000 °C. This Na-K-Fe-Cl-rich highly saline brine (~ 90 wt% NaCl eq.) was of magmatic origin and responsible for the Au mineralization. Two later stages involving cooler fluids (Th_L &lt; 300 °C) and gradually lower salinities (from 36.1 to 0.2 wt% NaCl eq.) trapped by halite-bearing and two-phase aqueous inclusions during stages 2 and 3, respectively, correspond to a late magmatic-hydrothermal system, that is probably related to a deep supercritical fluid exsolution. Salt melt inclusions represent the most likely parental fluid of K-silicate alteration and associated Au mineralization at Lindero. This uncommon type of fluid must have played an important role in Au transport and precipitation in shallow porphyry gold deposits.</p>","PeriodicalId":18682,"journal":{"name":"Mineralium Deposita","volume":"18 1","pages":""},"PeriodicalIF":4.8,"publicationDate":"2024-05-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140845380","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Hosts of Sn in reduced deep-seated W skarn systems: A case study on the world-class scheelite skarn deposit, Zhuxi, South China","authors":"Shiwei Song, Jingwen Mao, Rolf L. Romer, Wei Jian, Yongpeng Ouyang","doi":"10.1007/s00126-024-01271-6","DOIUrl":"https://doi.org/10.1007/s00126-024-01271-6","url":null,"abstract":"<p>Tin (Sn) and tungsten (W) behave incompatibly in reduced magmatic systems and may become enriched in late highly-evolved melts. Nonetheless, Sn and W rarely concentrate in the same deposit. In deposits formed by Sn- and W-bearing granites, this separation may be due to the contrasting behavior of Sn and W during exsolution of a magmatic fluid or the scavenging of Sn by silicate minerals. We illustrate the separation of Sn and W for the world-class Zhuxi W skarn deposit (South China). Although tin orebodies have not yet been identified within the Zhuxi deposit, tiny (commonly &lt; 20 μm) cassiterite grains are widespread within the endoskarn and the retrogressed exoskarn. We analyzed the W and Sn contents of the magmatic minerals biotite and ilmenite in ore-forming granites and the prograde anhydrous skarn minerals garnet, pyroxene and vesuvianite. Our data show that (i) magmatic ilmenite (65.5–79.1 ppm Sn; 8.7–14.3 ppm W) and biotite (109–120 ppm Sn; 1.3–6.3 ppm W) from biotite monzogranite strongly enrich Sn relative to W, implying that W partitioned more strongly into the magmatic fluids than Sn, (ii) there is 100 Kt non-recoverable Sn within the Zhuxi deposit in addition to the certified 3.44 Mt WO₃ reserves, and (iii) W is mainly hosted in scheelite, whereas Sn is dominantly sequestered in prograde skarn minerals, most importantly garnet (76–4086 ppm Sn, &lt; 42 ppm W), pyroxene (3–103 ppm Sn, &lt; 1 ppm W), and vesuvianite (43–361 ppm Sn, &lt; 2 ppm W). The formation of secondary cassiterite requires the release of silicate-bound Sn by alteration of primary skarn minerals, which depends on the availability of magmatic or metamorphic fluids. Deep-seated granites such as those associated with the Zhuxi skarn deposit, which crystallized at 5 km to 12.6 km depth, do not release or mobilize copious amounts of fluid. Therefore, the Zhuxi deposit, like other deep-seated reduced skarn systems shows little alteration and most Sn remains in silicate minerals and is economically non-recoverable. Thus, reduced, deep-seated W skarn systems are unlikely to have associated Sn orebodies even if significant amounts of Sn are present.</p>","PeriodicalId":18682,"journal":{"name":"Mineralium Deposita","volume":"22 1","pages":""},"PeriodicalIF":4.8,"publicationDate":"2024-05-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140845146","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Insights into fluid evolution and Re enrichment by mineral micro-analysis and fluid inclusion constraints: Evidence from the Maronia Cu-Mo ± Re ± Au porphyry system in NE Greece","authors":"Jan J. Falkenberg, Manuel Keith, Vasilios Melfos, Max Hohl, Karsten M. Haase, Panagiotis Voudouris, Alica Höss, Julia Wenske, Reiner Klemd, Christoph Beier, Martin Kutzschbach, Harald Strauss","doi":"10.1007/s00126-024-01273-4","DOIUrl":"https://doi.org/10.1007/s00126-024-01273-4","url":null,"abstract":"<p>Porphyry-epithermal veins hosting Re-rich molybdenite and rheniite (ReS₂) from the Maronia Cu-Mo ± Re ± Au porphyry in Thrace, NE Greece, provide new insights into the hydrothermal processes causing extreme Re enrichment. Quartz trace element chemistry (Al/Ti, Ge/Ti), Ti-in-quartz thermometry, and cathodoluminescence imaging reveal multiple quartz generations in consecutive hydrothermal quartz-sulfide veins associated with potassic, sericitic, and argillic alteration. Fluid inclusions in different quartz generations indicate that phase separation and fluid cooling are the main ore-forming processes in the porphyry stage (~ 500 – 350 °C), whereas mixing of a vapor-rich fluid with metalliferous (e.g., Pb, Zn, Au) meteoric water forms the epithermal veins (~ 280 °C). These processes are recorded by trace element ratios in pyrite that are sensitive to changes in fluid temperature (Se/Te), fluid salinity (As/Sb, Co/As), and mixing between fluids of magmatic and meteoric origin (Se/Ge). Highly variable intra-grain δ³⁴S values in pyrite record S isotope fractionation during SO₂ disproportionation and phase separation, emphasizing the importance of in situ δ³⁴S analysis to unravel ore-forming processes. High δ³⁴S (~ 4.5‰) values of sulfides are indicative of low SO₄²⁻/H₂S fluid ratios buffered by the local host rocks and mixing of the magma-derived fluid with meteoric water. The formation of Re-rich molybdenite (~ 6600 ppm) is favored by cooling and reduction of a magma-derived, high-temperature (~400 °C), oxidized, and Re-rich fluid triggering efficient Re precipitation in early veins in the potassic alteration zone. The systematic temporal fluid evolution therefore reveals that coeval cooling and reduction of oxidized Re-rich fluids cause extreme Re enrichment at the Maronia porphyry system.</p>","PeriodicalId":18682,"journal":{"name":"Mineralium Deposita","volume":"106 1","pages":""},"PeriodicalIF":4.8,"publicationDate":"2024-05-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140845140","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Where are the feeder channels for platinum reefs in the Bushveld Complex?","authors":"Rais Latypov, Sofya Chistyakova","doi":"10.1007/s00126-024-01272-5","DOIUrl":"https://doi.org/10.1007/s00126-024-01272-5","url":null,"abstract":"<p>The Bushveld Complex in South Africa hosts the lion’s share of the world’s noble metal resources in platinum reefs – thin layers of silicate/chromite rocks containing platinum-rich sulphides. The reefs are widely attributed to multiple replenishments by ore-forming magmas that have been entering the evolving Bushveld chamber through numerous feeder conduits. The replenishment events are marked by regional and local disconformities/unconformities, significant isotopic shifts, and notable reversals in the whole-rock and mineral compositions. Surprisingly, however, so far no single feeder conduit for platinum reefs has been found despite extensive surface and underground mining for over a century. Feeder conduits appear entirely absent from the Bushveld Complex. This paradox has long been known but has never been specifically addressed. Here, we suggest that the absence of feeder channels is a natural consequence of the magma chamber replenishment through a cumulate pile. The fossilization of the feeder channels in the cumulate pile is likely impeded by two principal factors: (a) a cumulate pile is too hot to enable efficient cooling and crystallization of magma flowing through the channels, and (b) the channels are closed by an adjacent elastically deformable pile immediately after cessation of the magma emplacement. The feeding dykes are thus absent because there is little chance for the conduits to get preserved in a hot and deformable cumulate pile of layered intrusions.</p>","PeriodicalId":18682,"journal":{"name":"Mineralium Deposita","volume":"7 1","pages":""},"PeriodicalIF":4.8,"publicationDate":"2024-04-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140818005","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Sedimentary and metamorphic processes priming black shale for magmatic assimilation of sulfur: an example from the Virginia Formation, Minnesota, United States","authors":"Ville J. Virtanen, Jussi S. Heinonen, Lena Märki, Matthieu E. Galvez, Ferenc Molnár","doi":"10.1007/s00126-024-01268-1","DOIUrl":"https://doi.org/10.1007/s00126-024-01268-1","url":null,"abstract":"<p>The copper-nickel(-platinum-group element) sulfide resources of the Duluth Complex, Minnesota, USA, formed by assimilation of sulfur from the Virginia Formation black shale. In the normal black shale of the Virginia Formation, sulfur is mainly hosted in disseminated pyrite, whereas mm-scale pyrrhotite laminae dominate in the sulfur-rich Bedded Pyrrhotite Unit. The Bedded Pyrrhotite Unit was the main supply of sulfur in some of the magmatic sulfide deposits but its origin has not been studied in detail. Using Raman spectroscopy, we show that the carbonaceous material within the regionally metamorphosed normal black shale is graphitized biogenic material. The Bedded Pyrrhotite Unit contains pyrobitumen that represents residues of oil that accumulated to porous horizons, which formed due to dissolution of precursor sedimentary clasts. Replacement of the clasts by quartz and sulfides facilitated the formation of the pyrrhotite laminae of the Bedded Pyrrhotite Unit, which likely occurred during regional metamorphism.</p><p>The pyrite-bearing normal black shale experienced loss of H₂O, C_org, and sulfur during devolatilization caused by the Duluth Complex. The contact-metamorphosed Bedded Pyrrhotite Unit shows no systematic depletion of volatiles and is the most C_org and sulfur-rich part of the Virginia Formation. During devolatilization, sulfur was preserved because unlike pyrite, pyrrhotite was stable. Consequently, magmatic assimilation of sulfur from the Bedded Pyrrhotite Unit required partial melting. Retrograde hydration introduced H₂O, and possibly C_org, and sulfur, to the contact-metamorphosed Bedded Pyrrhotite Unit, which further affected the volatile budget. Our findings highlight why constraining diagenetic and regional metamorphic processes is important to understand magma-sediment interaction processes.</p>","PeriodicalId":18682,"journal":{"name":"Mineralium Deposita","volume":"51 1","pages":""},"PeriodicalIF":4.8,"publicationDate":"2024-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140642498","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Sulfide saturation in reduced magmas during generation of the Gangdese juvenile lower crust: Implications for porphyry Cu–Au mineralization in the Gangdese belt, Tibet","authors":"Jin-Lei Sun, Zhong-Jie Bai, Hong Zhong, Xu Liu, Jing-Jing Zhu, Lan Chen, Wei-Guang Zhu","doi":"10.1007/s00126-024-01269-0","DOIUrl":"https://doi.org/10.1007/s00126-024-01269-0","url":null,"abstract":"<p>The S saturation and oxidation states of arc magmas are important factors in the formation of porphyry Cu–Au deposits. The Milin juvenile lower crustal cumulates (86.7–84.3 Ma) in the Gangdese provide insights into how sulfide saturation and oxidation states control porphyry mineralization. Zircons from the cumulates have low Ce⁴⁺/Ce³⁺ ratios (21–90) and reduced oxygen fugacities (ΔFMQ–1.8±0.5), which cannot be explained by fractional crystallization or crustal contamination, suggesting inheritance from a mantle source. Partial melting of the mantle under reduced conditions produced a sulfide-saturated primary arc magma with low chalcophile element contents owing to the residual sulfide in the mantle. The Milin lower crustal cumulates contain sulfides, indicating that the magma reached sulfide saturation in the early stages of magmatic differentiation. Based on our model, the primary arc magma before sulfide saturation contained 66.7 ppm Cu and 1.0 ppb Au. The residual magma after sulfide saturation in the lower crust contained 33–66 ppm Cu, 0.13–0.93 ppb Au; i.e., lower contents than those in arc basalts worldwide. Both these factors hindered the formation of Late Cretaceous large porphyry Cu–Au deposits in the Gangdese belt. Remelting of the Milin sulfide-rich cumulates can generate a Cu-rich andesitic magma only under high temperature and high-<i>fO</i>_<i>2</i> conditions, and a melt with low Cu content under low temperature even high-<i>fO</i>_<i>2</i> conditions. Thus, the temperature plays a crucial role in the remelting of the lower crust whether provide enough metals to match the Gangdese Miocene post-collisional porphyry Cu deposit.</p>","PeriodicalId":18682,"journal":{"name":"Mineralium Deposita","volume":"25 1","pages":""},"PeriodicalIF":4.8,"publicationDate":"2024-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140640071","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The In-Ga-Sb association of the post-Variscan Zn-Pb-Ag vein deposit at Lautenthal, Upper Harz Mountains, Germany: sphalerite mineral chemistry","authors":"Torsten Graupner, Sören Henning, Simon Goldmann, Sebastian Fuchs, Klaus Stedingk, Wilfried Liessmann, Sven Birkenfeld","doi":"10.1007/s00126-024-01261-8","DOIUrl":"https://doi.org/10.1007/s00126-024-01261-8","url":null,"abstract":"<p>The Lautenthal sphalerite-galena vein deposit is part of the world-class Upper Harz Pb-Zn-Ag district in the Harz uplift block of the Paleozoic Variscan fold belt in Germany. Its sphalerite-dominated mineral association was studied using bulk-ore chemistry, electron probe microanalysis, and laser ablation-ICP-mass spectrometry. Gallium and locally In are the main high-tech-relevant trace elements hosted by sphalerite, with up to 150 ppm Ga and up to 380 ppm In in hand-picked sphalerite samples (mean In/Zn, 0.70 × 10⁻³). Ore concentrates (≤ 50 kg) contain up to 65 ppm Ga and up to 109 ppm In (mean In/Zn, 0.36 × 10⁻³). Accessory Fe-Co-rich gersdorffite-1 occurs in the earlier quartz-sulfide ore stage and Sb-rich gersdorffite-2 in the later carbonate-sulfide stage. Enrichment patterns of In are either defined by overprinting textures in the Fe-richer sphalerite-1 of the earlier stage, or relate to primary growth zoning in Fe-poor sphalerite-2 of the later stage. Using the sphalerite geothermometer GGIMFis, formation temperatures (median) of sphalerite-1 were estimated at ~ 230 °C for the Lautenthal orebody and at ~ 175 °C for the Bromberg orebody, which may indicate lateral T-zonation for the earlier ore stage. Sphalerite-2 data indicate formation temperatures of ~ 185 °C (median). Copper-bearing brines of the carbonate-sulfide stage with assumed temperatures of ~ 250 °C initiated replacement of In-poor sphalerite-1 by chalcopyrite and remobilization of Zn and trace elements. Indium-rich sphalerite-2 occurs associated with calcite and fine-grained galena. A direct spatial or temporal link of ore formation to a magmatic-hydrothermal system is unlikely, which contrasts to In-rich epithermal and tin-polymetallic vein deposits worldwide.</p>","PeriodicalId":18682,"journal":{"name":"Mineralium Deposita","volume":"171 1","pages":""},"PeriodicalIF":4.8,"publicationDate":"2024-04-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140551865","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}