Subjects -> MINES AND MINING INDUSTRY (Total: 81 journals)
Showing 1 - 42 of 42 Journals sorted alphabetically
American Mineralogist     Hybrid Journal   (Followers: 16)
Applied Earth Science : Transactions of the Institutions of Mining and Metallurgy     Hybrid Journal   (Followers: 4)
Archives of Mining Sciences     Open Access   (Followers: 3)
AusiMM Bulletin     Full-text available via subscription   (Followers: 1)
BHM Berg- und Hüttenmännische Monatshefte     Hybrid Journal   (Followers: 2)
Canadian Mineralogist     Full-text available via subscription   (Followers: 7)
Clay Minerals     Hybrid Journal   (Followers: 9)
Clays and Clay Minerals     Hybrid Journal   (Followers: 5)
Coal Science and Technology     Full-text available via subscription   (Followers: 3)
Contributions to Mineralogy and Petrology     Hybrid Journal   (Followers: 14)
Environmental Geochemistry and Health     Hybrid Journal   (Followers: 2)
European Journal of Mineralogy     Hybrid Journal   (Followers: 14)
Exploration and Mining Geology     Full-text available via subscription   (Followers: 3)
Extractive Industries and Society     Hybrid Journal   (Followers: 2)
Gems & Gemology     Full-text available via subscription   (Followers: 2)
Geology of Ore Deposits     Hybrid Journal   (Followers: 5)
Geomaterials     Open Access   (Followers: 3)
Geotechnical and Geological Engineering     Hybrid Journal   (Followers: 9)
Ghana Mining Journal     Full-text available via subscription   (Followers: 3)
Gold Bulletin     Hybrid Journal   (Followers: 2)
Inside Mining     Full-text available via subscription  
International Journal of Coal Geology     Hybrid Journal   (Followers: 4)
International Journal of Coal Preparation and Utilization     Hybrid Journal   (Followers: 2)
International Journal of Coal Science & Technology     Open Access   (Followers: 1)
International Journal of Hospitality & Tourism Administration     Hybrid Journal   (Followers: 15)
International Journal of Mineral Processing     Hybrid Journal   (Followers: 8)
International Journal of Minerals, Metallurgy, and Materials     Hybrid Journal   (Followers: 11)
International Journal of Mining and Geo-Engineering     Open Access   (Followers: 4)
International Journal of Mining and Mineral Engineering     Hybrid Journal   (Followers: 8)
International Journal of Mining Engineering and Mineral Processing     Open Access   (Followers: 6)
International Journal of Mining Science and Technology     Open Access   (Followers: 4)
International Journal of Mining, Reclamation and Environment     Hybrid Journal   (Followers: 6)
International Journal of Rock Mechanics and Mining Sciences     Hybrid Journal   (Followers: 9)
Journal of Analytical and Numerical Methods in Mining Engineering     Open Access  
Journal of Applied Geophysics     Hybrid Journal   (Followers: 17)
Journal of Central South University     Hybrid Journal   (Followers: 1)
Journal of China Coal Society     Open Access  
Journal of China University of Mining and Technology     Full-text available via subscription   (Followers: 1)
Journal of Convention & Event Tourism     Hybrid Journal   (Followers: 6)
Journal of Geology and Mining Research     Open Access   (Followers: 10)
Journal of Human Resources in Hospitality & Tourism     Hybrid Journal   (Followers: 9)
Journal of Materials Research and Technology     Open Access   (Followers: 2)
Journal of Metamorphic Geology     Hybrid Journal   (Followers: 17)
Journal of Mining Institute     Open Access  
Journal of Mining Science     Hybrid Journal   (Followers: 5)
Journal of Quality Assurance in Hospitality & Tourism     Hybrid Journal   (Followers: 6)
Journal of Sustainable Mining     Open Access   (Followers: 3)
Journal of the Southern African Institute of Mining and Metallurgy     Open Access   (Followers: 6)
Lithology and Mineral Resources     Hybrid Journal   (Followers: 4)
Lithos     Hybrid Journal   (Followers: 12)
Mine Water and the Environment     Hybrid Journal   (Followers: 5)
Mineral Economics     Hybrid Journal   (Followers: 2)
Mineral Processing and Extractive Metallurgy : Transactions of the Institutions of Mining and Metallurgy     Hybrid Journal   (Followers: 14)
Mineral Processing and Extractive Metallurgy Review     Hybrid Journal   (Followers: 5)
Mineralium Deposita     Hybrid Journal   (Followers: 5)
Mineralogia     Open Access   (Followers: 2)
Mineralogical Magazine     Hybrid Journal   (Followers: 1)
Mineralogy and Petrology     Hybrid Journal   (Followers: 5)
Minerals     Open Access   (Followers: 2)
Minerals & Energy - Raw Materials Report     Hybrid Journal   (Followers: 1)
Minerals Engineering     Hybrid Journal   (Followers: 14)
Mining Engineering     Full-text available via subscription   (Followers: 7)
Mining Journal     Full-text available via subscription   (Followers: 4)
Mining Report     Hybrid Journal   (Followers: 3)
Mining Technology : Transactions of the Institutions of Mining and Metallurgy     Hybrid Journal   (Followers: 4)
Mining, Metallurgy & Exploration     Hybrid Journal  
Natural Resources & Engineering     Hybrid Journal  
Natural Resources Research     Hybrid Journal   (Followers: 4)
Neues Jahrbuch für Mineralogie - Abhandlungen     Full-text available via subscription   (Followers: 1)
Physics and Chemistry of Minerals     Hybrid Journal   (Followers: 4)
Podzemni Radovi     Open Access  
Rangeland Journal     Hybrid Journal   (Followers: 4)
Réalités industrielles     Full-text available via subscription  
Rem : Revista Escola de Minas     Open Access  
Resources Policy     Hybrid Journal   (Followers: 4)
Reviews in Mineralogy and Geochemistry     Hybrid Journal   (Followers: 5)
Revista del Instituto de Investigación de la Facultad de Ingeniería Geológica, Minera, Metalurgica y Geográfica     Open Access  
Rock Mechanics and Rock Engineering     Hybrid Journal   (Followers: 9)
Rocks & Minerals     Hybrid Journal   (Followers: 5)
Rudarsko-geološko-naftni Zbornik     Open Access  
Transactions of Nonferrous Metals Society of China     Hybrid Journal   (Followers: 9)
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Journal Cover
Mineralium Deposita
Journal Prestige (SJR): 1.601
Citation Impact (citeScore): 4
Number of Followers: 5  
  Hybrid Journal Hybrid journal (It can contain Open Access articles)
ISSN (Print) 1432-1866 - ISSN (Online) 0026-4598
Published by Springer-Verlag Homepage  [2626 journals]
  • Correction to: The inherent link between ore formation and geometallurgy
           as documented by complex tin mineralization at the Hämmerlein deposit
           (Erzgebirge, Germany)
    • Abstract: Clarification regarding the calculation of the MAMA ratio.
      PubDate: 2019-03-22
      DOI: 10.1007/s00126-019-00874-8
  • Geochemical characteristics of magnetite in Longqiao skarn iron deposit in
           the Middle-Lower Yangtze Metallogenic Belt, Eastern China
    • Abstract: Abstract The Longqiao Fe deposit is the only large stratabound Fe skarn in Eastern China. This extensive ore body is suitable for investigating the spatial variations in trace elements in magnetite from the intrusion to the wall rocks and tracing the evolution of the mineralizing fluid in a skarn deposit. Magnetite samples were collected every 200 m from the ore-forming gabbro-diorite to the edge of the ore body, including the diopside-magnetite and epidote-chlorite-magnetite stages. Our results show that magnetite proximal to the gabbro-diorite displays lower Mg, Al, and Si and higher contents of Ti and V than those found further from the gabbro-diorite. The hydrothermal fluids in both diopside-magnetite and epidote-chlorite-magnetite stages were influenced by reaction with marine sedimentary rocks. Magnetites from different parts of the ore body display a wide range of trace element contents and fall into the porphyry and skarn fields on a (Mn + Al) vs. (Ti + V) discrimination diagram. Based on our results and published data, we propose that the early-stage magnetite from skarn and iron oxide-apatite (IOA) Fe deposits is compositionally similar, and fluid compositional variations are largely dependent on differences in the composition of the wall rock and the intensity of fluid-rock interactions. This results in a large variation in (Ti + V) in magnetite compositions from skarn deposits in the (Mn + Al) vs. (Ti + V) discrimination diagram, which is different from IOA deposits. This study shows that magnetite trace element evolution trends can provide a reliable indication to recognize skarn and IOA deposit types.
      PubDate: 2019-03-22
      DOI: 10.1007/s00126-019-00871-x
  • Supergene gold in silcrete as a vector to the Scuddles volcanic massive
           sulfides, Western Australia
    • Abstract: Abstract This study reports data on the first occurrence of economic supergene Au in a near-surface silcrete horizon over the Scuddles volcanic massive sulfide (VMS) deposit in the Golden Grove district, Western Australia. A deep weathering profile was developed on dacite, rhyodacite, siltstone, and breccia that host primary Cu, Zn, and Pb sulfides with Au-Ag ore. From the base, the weathering profile at Scuddles is subdivided into five main zones: (1) supergene sulfide enrichment zone; (2) supergene oxide enrichment zone; (3) ferruginous saprolite; (4) leached zone of kaolinitic saprolite and silcrete; and (5) lateritic zone of mottled clays, ferruginous duricrust, and gravels. Silcrete at Scuddles hosts supergene Au deposit that formed in two generations: the first is intimately associated with Ag halides during supergene enrichment of the primary VMS, and the second is associated with kaolinite in dissolution cavities inside Ag halides during lateritic weathering. These two Au generations imply more than one mechanism of Au remobilization and formation, multiple fluid pathways, and superimposed episodes of weathering under variable timing and climatic conditions. Gold grains are pure, nanocrystalline (up to 10 nm) and clustered together forming microcrystalline aggregates. A few Au grains are residual in silcrete with Ag-Sb-rich cores and Ag-poor rims possibly formed during dealloying of Ag and Sb. Chemically, Au in silcrete is associated with a multi-element concentration of Ag, I, Br, Cl, Sb, Sn, Bi, Hg, Mo, W, Te, and Ge. Gold and Ag in the supergene weathering profile were mobilized to silcrete as a halide complex under acidic and saline conditions generated during the oxidation of massive sulfides at depth. The precipitation of Au-Ag halides in the silcrete may have taken place in response to a rise in pH. Gold was likely remobilized with kaolinite from the surface lateritic zone, facilitated by decays of plant roots and bioturbation. The clustered spongy, cube-octahedral, platy (six-sided), dendritic-, and reniform-like morphologies of Au in cavities inside Ag halides may indicate biogenic-related processes in its precipitation. Recognizing Au-Ag-rich silcrete over the buried VMS at Scuddles highlights the significance of the silcrete in finding buried VMS, particularly if the gossan is absent.
      PubDate: 2019-03-15
      DOI: 10.1007/s00126-019-00868-6
  • Atmosphere oxygen cycling through the Proterozoic and Phanerozoic
    • Abstract: Abstract Variations in atmosphere oxygen and ocean sulfate concentrations through time are regarded as important controls on the cycles of sediment-hosted and volcanic-hosted ore deposits. However, estimates of atmosphere oxygen in the Proterozoic have been frustrated by the lack of a direct measurement method and conflicting evidence from various proposed geochemical proxies. Studies in the 1970s to 1990s suggested a relatively oxygenated atmosphere (> 3 wt% O2) in the Proterozoic. However, since the late 1990s, new proxies and modelling have suggested very much lower levels of oxygen (< 0.02 wt% O2). Focusing on redox-sensitive trace elements, here we combine a dataset of over 3000 LA-ICP-MS trace-element analyses on sedimentary pyrite, standardised against Berner’s Phanerozoic O2 modelling and direct measurement of oxygen concentrations in fluid inclusions in sedimentary halite, to develop the first detailed estimate for atmosphere O2 concentration and secular variation from 2200 Ma to the present. The estimates suggest dynamic cycles of atmosphere oxygen that increased in frequency through time. There were possibly three first-order cycles in the Proterozoic varying from 400 to 600 million years in length and a further five first-order cycles in the Phanerozoic from 60 to 120 million years in length. Our estimates of oxygen concentration are at odds with most previous estimates. We suggest, rather than very low atmosphere oxygen in the Proterozoic, the mean concentration was about 7 wt%, rising to a mean of about 10 wt% in the Phanerozoic, but with significant cyclic variation of up to a maximum concentration of possibly over 30 wt%. We observe that the proposed oxygen cycles correlate with biodiversity cycles and to the timing of major stratiform base-metal deposits in sedimentary basins. For example, minima in atmosphere oxygenation correlate with mass extinction events and stratiform Zn–Pb–Ag deposits, whereas maxima in oxygenation correlate with major evolutionary events, global periods of evaporite formation and the timing of stratiform copper deposits.
      PubDate: 2019-03-12
      DOI: 10.1007/s00126-019-00873-9
  • Geology, mineralization, and fluid inclusion characteristics of the
           Koitash redox-intermediate W–Mo skarn and W–Au stockwork deposit,
           western Uzbekistan, Tien Shan
    • Abstract: Abstract The Koitash W–Mo skarn deposit in the Tien Shan Gold Belt contained resources of 60 kt WO3 in altered skarn (averaging 0.56% WO3 and 0.029% Mo) and an additional 42 kt WO3 in separate zones of phyllic alteration (averaging 0.30% WO3, 0.97 g/t Au, 0.67% Cu, and 0.02% Bi). It is related to an Early Permian multiphase granodiorite–granite–leucogranite pluton that is composed of medium- to high-K, transitional metaluminous to peraluminous, weakly oxidized–weakly reduced, ilmenite–titanite series granitoids. The pluton was emplaced in a tectonic domain with inferred ancient continental crust; the latter, coupled with possible ascent of hot asthenospheric material, has likely defined a distinct W–Mo–Au metallogenic assemblage forming in a post-collisional environment. The deposit includes redox-intermediate prograde and retrograde pyroxene–garnet skarns, partially overprinted by propylitic and phyllic alteration assemblages, comprising scheelite, molybdenite, Cu–Bi–Ag–Te sulfides, and sulfosalts, as well as native Bi and Au. Compositional similarities between W–Mo deposits, containing Au–W–Cu–Bi mineralization in late alteration assemblages, and coeval intrusion-related Au-dominant (with minor W, Bi, etc.) deposits in the region support their possible genetic links. Fluid inclusion data indicate the involvement of carbonic-free moderately saline (10.5–15.0 to 8.0–11.7 wt% NaCl-eq.), high-pressure (2000 to 1500 bars), hot (> 550–600 °C) aqueous fluid, which was sourced from crystallizing magma and formed prograde calcic skarn. This fluid was followed by moderately saline, Ca-rich (14–16 wt% NaCl, 19–21 wt% CaCl2), lower pressure (800 bars) fluids toward the retrograde skarn stage, with the deposition of scheelite in association with pyrrhotite and molybdenite, locally with minor fluorite. Propylitic quartz–amphibole–chlorite–oligoclase–calcite, with scheelite, pyrrhotite, locally molybdenite, assemblages formed from boiling high-methane aqueous-carbonic fluids at temperatures of 370–400 °C and pressures of 950–1000 bars. Phyllic quartz–sericite–Fe–carbonate, locally with albite, fluorite, chlorite, scheelite, molybdenite, and other sulfides, also Bi and Au minerals, alteration assemblages initially formed from homogeneous and then from boiling aqueous-carbonic, low-salinity fluids at temperatures of 365–370 to 300–315 °C and pressures of ~ 2000 bars. δ34S increases from retrograde skarn (δ34S = + 2.0 to + 2.3‰) through propylitic (δ34S = + 3.0 to + 3.4‰) to phyllic alteration (δ34S = + 4.2 to + 4.7‰) stages.
      PubDate: 2019-03-08
      DOI: 10.1007/s00126-019-00869-5
  • Supergene oxidation of epithermal gold-silver mineralization in the
           Deseado massif, Patagonia, Argentina: response to subduction of the Chile
    • Abstract: Abstract Radiometric ages for supergene alunite and jarosite effectively date the oxidation of former concentrations of pyrite and any associated sulfide minerals. These K-bearing sulfate minerals, formed under low-pH conditions, are uncommon supergene products in low-sulfidation epithermal deposits because of the general paucity of pyrite for acid generation. For this reason, the age of supergene oxidation—locally to depths of 200 m or more—in the epithermal Au-Ag deposits of the Deseado massif, located in the extra-Andean foreland of Patagonia, southern Argentina, has remained unknown. Although, theoretically, the oxidation could have taken place anytime between the Late Jurassic, when the Au-Ag mineralization formed, and Pleistocene, K-Ar ages for alunite and jarosite from two widely separated and unusually pyritic, Ag-bearing hydrothermal breccias (Lejano and Libanesa) show it to have been mid-Miocene, 13.8 ± 1.8 Ma. This is the time when the Deseado massif underwent appreciable regional-scale tectonic uplift and valley incision, following ~ 140 myr during which the region was topographically subdued and the site of either fluvio-lacustrine or shallow-marine sedimentation. The uplift, combined with increasing aridity due to the orographic rain shadow caused by growth of the Patagonian Andes to the west and enhanced by global cooling, would have depressed regional groundwater tables, thereby promoting the supergene sulfide oxidation. The mid-Miocene uplift appears to have been triggered by development of a slab tear and slab window beneath the Deseado massif during early stages of subduction of the Chile oceanic-ridge spreading center at the Pacific margin. Supergene sulfide oxidation in both the Deseado massif and Atacama Desert of northern Chile was the result of Cenozoic uplift during progressive aridification, although the causes of these phenomena were radically different. However, when the supergene oxidation was taking place in the Deseado massif, up to 30 myr of supergene activity in the Atacama Desert were coming to an end because of the onset of hyperaridity.
      PubDate: 2019-03-01
      DOI: 10.1007/s00126-018-0814-4
  • Tourmaline in the Passagem de Mariana gold deposit (Brazil) revisited:
           major-element, trace-element and B-isotope constraints on metallogenesis
    • Abstract: Abstract Tourmaline at Passagem de Mariana forms three associations: stratiform tourmalinite (T1), wall-rock alteration around quartz-sulfide veins (T2), and clusters within the veins (T3). The major-element composition of tourmaline is similar in all, with Mg/(Mg+Fe) from 0.59 to 0.83 (mean 0.69 ± 0.03) and total Al contents from 6.2 to 6.6 atoms per formula unit (apfu). The Y-site Al (0.2–0.6 apfu) is charge-balanced by the exchange NaMg(Al☐)−1. Tourmalinite type (T1) is unzoned, whereas T2 and T3 grains display increasing Ti and Ca from core to rim. In situ trace-element analyses of T1 grains were prohibited by grain size and inclusions. The T2 and T3 tourmaline have similar trace-element values, except higher concentrations of Zn, Cu, and Co in T3, which is consistent with its location in the mineralized veins. The δ11B values of T1 and T2 tourmaline range from − 17.8 to − 9.7‰, with indistinguishable mean values (− 13.9 ± 1.9 and − 13.8 ± 1.6‰, respectively), supporting field evidence that T1 tourmalinite is hydrothermal. The δ11B values of T3 tourmaline are about 5‰ higher (mean − 8.9 ± 1.3‰), which we ascribe to depletion of 10B in the vein fluid due to tourmalinization of wall rocks. This implies that the initial δ11B value of hydrothermal fluid was about − 11‰ (for 400 °C and the T1–T2 mean δ11B = − 14‰). This indicates a crustal boron source but is otherwise non-specific. Based on geological arguments, we favor a source in the Minas Supergroup metasedimentary units hosting the deposit.
      PubDate: 2019-03-01
      DOI: 10.1007/s00126-018-0819-z
  • Stable isotope and fluid inclusion study of sediment-hosted stratiform
           copper deposits from the Neuquén Basin, Argentina
    • Abstract: Abstract The Los Chihuidos and El Porvenir deposits of the Neuquén Basin are examples of sediment-hosted stratiform Cu deposits generated by interaction of hydrocarbons and formation water with host red beds and metal-charged basinal brines. During early diagenesis of red beds precipitated hematite, kaolinite at 60 °C from meteoric water followed by calcite 1 (δ13C − 8 to − 3.3‰) and barite (δ34S + 4.1‰) with increasing temperature (75–85 °C) from an evolved surface fluid (δ18Ofluids + 0.9 to + 2.7‰). During the Tertiary Andean orogeny, hydrocarbons and formation water migrated and reacted with the red beds resulting in bleaching of the sandstone. Smectite (fluid δ18O − 2.2‰ and δD − 73.7‰), chlorite-smectite mixed-layer minerals (fluid δ18O − 6.9‰ and δD − 84‰), pyrite (δ34S + 10.2‰), and calcite 2 (δ13C − 12.9 to − 6.8‰) formed as by-product of the redox reactions. Calcite 2 formed from low-salinity fluids (0.4 to 5.9 wt% NaCl equiv.) at slightly higher temperatures (125–145 °C) at El Porvenir and at Los Chihuidos deposit (80–105 °C). During subsequent uplift, metal-charged basinal brines flowed into the bleached sandstone and precipitated chalcopyrite-bornite (δ34S + 12.3‰) followed by chalcocite-spionkopite (δ34S − 64 to + 4.1‰). Calcites 3a (δ13C − 19 to − 10.1‰) and 3b (δ13C − 31.4 to − 9.5‰) that accompanied Fe-Cu and Cu sulfides, respectively, formed from saline fluids (up to 21.3 wt% NaCl equiv.) at temperatures of 159–70 °C. The δ18O values (+ 5.6 to + 11.4‰) of fluids in equilibrium with calcite 3a are similar to oilfield and basinal brines. Fluids in equilibrium with calcite 3 in Los Chihuidos and calcite 3b in El Porvenir show much lighter δ18O values (− 7.3 to − 4.6‰ and − 0.6 to + 2.3‰, respectively), which suggests the involvement of methane as the main reductant and possibly meteoric water interaction.
      PubDate: 2019-03-01
      DOI: 10.1007/s00126-018-0815-3
  • Chronology of the Kašperské Hory orogenic gold deposit, Bohemian
           Massif, Czech Republic
    • Abstract: Abstract The Kašperské Hory deposit represents one of the economically most important hydrothermal gold deposits in the Bohemian Massif (Czech Republic). We present new Re–Os age determinations for sulfides complemented by Ar–Ar determinations on silicate minerals in order to provide temporal constraints on the deposit formation. Arsenopyrite and molybdenite formed during gold-bearing stages I–III yielded similar Re–Os ages between ~ 341 and 333 Ma, overlapping with the Ar–Ar cooling age of the metamorphic host rocks below ~ 500 °C. Continuous cooling of the ore system below 270 °C during stage III is reflected by Ar–Ar muscovite ages spanning from ~ 332 to 325 Ma representing the long interval of formation of gold-productive stage III. Thus, the Kašperské Hory gold deposit is younger than the gold deposits spatially associated with the Central Bohemian Plutonic Complex (~ 349–339 Ma) belonging to the Central Bohemian Metallogenetic Zone (e.g., Mokrsko-West, Jílové, Petráčkova Hora). This may indicate a rather close relationship to the nearby Moldanubian Batholith while still suggesting an intimate link between mineralization and Variscan orogenesis and associated magmatism.
      PubDate: 2019-03-01
      DOI: 10.1007/s00126-018-0822-4
  • The Roc Blanc orogenic Pb-Zn-Ag-Au deposit (Morocco): a product of
           metamorphic dehydration and CO 2 devolatilization during exhumation of the
           Variscan Jebilet massif
    • Abstract: Abstract The Roc Blanc Pb-Zn-Ag ± Au vein system in the Variscan Central Jebilet massif, Morocco, is confined within the contact metamorphic aureole of S- and I-type calc-alkaline granitic stocks (327 ± 4 to 295 ± 15 Ma) along the Marrakech Shear Zone. Host rocks consist of a succession of greenschist- to amphibolite-facies metasedimentary and metavolcaniclastic rocks of Carboniferous age. The ore mineralogy is predominantly base metal and Ag-bearing sulfides and sulfosalts, intergrown with quartz and carbonates. Late-stage gold mineralization is commonly present as electrum in intimate association with all major generations of sulfide and sulfosalt minerals. Ore-related hydrothermal alteration includes silicification, sericitization, chloritization, and carbonatization. Chlorite and arsenopyrite geothermometry suggest mean temperatures of 364 and 350 °C; respectively. Calculated δ18Ofluid values of 15 to 18‰ are consistent with metamorphic fluid sources, by which the mineralizing fluids were produced during the emplacement of granitic intrusions and subsequent devolatilization of graphitic black shale and interlayered carbonate beds. Lead and strontium isotope data constrain the source of the ore-forming components (i.e., metals and sulfur) to the enclosing host rocks. A decrease in temperature during fluid ascent and subsequent alteration-associated fluid-rock interaction resulted in the deposition of the Pb-Zn-Ag ± Au mineralization in a post-collisional extensional setting.
      PubDate: 2019-03-01
      DOI: 10.1007/s00126-018-0818-0
  • Mineralogy and titanite geochronology of the Caojiaba W deposit,
           Xiangzhong metallogenic province, southern China: implications for a
           distal reduced skarn W formation
    • Abstract: Abstract The Caojiaba tungsten deposit (19.03 Mt@ 0.37 wt% WO3) is hosted by skarn along the contact between clastic and carbonate rocks in the Xiangzhong Metallogenic Province of southern China. The deposit is characterized by an early prograde skarn containing low andraditic garnet (Ad0.7–21.9) and hedenbergitic pyroxene (Hd52.9–77.3) overprinted by a retrograde biotite–chlorite assemblage and then by quartz–scheelite veins, similar to well-studied reduced tungsten skarns worldwide. Scheelite has low MoO3 (0.01–0.16 wt%), and ore commonly contains up to 1.5 ppm Au and up to 0.33 wt% Sb. Sensitive high-resolution ion microprobe (SHRIMP) U–Pb analyses of hydrothermal titanite coexisting with scheelite in three skarn ore samples provide ages between 206 ± 5 Ma and 196 ± 3 Ma (2σ). Our new ages demonstrate that the tungsten mineralization took place at Caojiaba between 206 and 196 Ma, overlapping the 228–201 Ma emplacement age of granitic rocks in the Xiangzhong Metallogenic Province. Mineralogical and geochronological evidence collectively indicates that Caojiaba is a distal reduced W skarn deposit. The 226–196 Ma granite-related W mineralization recognized throughout the province has a possible link with the widespread Sb–Au mineralization in the region.
      PubDate: 2019-03-01
      DOI: 10.1007/s00126-018-0816-2
  • Ore-shoot formation in the Main Reef Complex of the Fairview
           Mine—multiphase gold mineralization during regional folding, Barberton
           Greenstone Belt, South Africa
    • Abstract: Abstract Gold production in Fairview Mine in the Barberton Greenstone Belt, South Africa, is focused on high-grade, steeply plunging ore shoots contained within a gently undulating system of spaced, low-displacement, broadly bedding-parallel faults, and shear zones, collectively referred to as the Main Reef Complex. This shear zone system is developed in metaturbiditic sedimentary rocks of the Mesoarchean Fig Tree Group on the steep western limb of the regional (D3), refolded, and distinctly arcuate Ulundi Syncline. Shear zones are preferentially localized along lithological contacts with pronounced rheological contrasts, particularly pronounced along the limbs of tightly infolded ultramafic schist against Fig Tree Group metasedimentary rocks. The main ore shoot of the MRC at Fairview shows a steep southeasterly plunge that can be traced for > 2000 m down-plunge, parallel to the fold hinge (F3b) that refolds the Ulundi Syncline. Fabrics and structures in the ore shoot record combined top-to-the NW thrust sense and dextral strike-slip kinematics and strongly constrictional strains interpreted to indicate dextral transpression and associated steep extrusion of the rocks during progressive NW-SE (D3) shortening. A combination of structural and lithological controls govern ore-shoot formation and gold mineralization. The main ore shoot corresponds to dilational jog geometry that developed during dextral transpression, bedding-parallel shearing consistent with the flexural-slip refolding (F3b) of the Ulundi Syncline. High-grade pockets correlate with sheared, commonly dismembered, graphite-rich and sulfide-mineralized shale units, testifying to the preferential fluid focusing and strain localization into incompetent shale units during deformation. Cross-cutting relationships with other auriferous reefs from the Fairview Mine complex indicate a late timing of the MRC-type mineralization, underlining the complex fluid focusing and utilization of differently orientated structures with different kinematics during progressive deformation and either episodic or protracted fluid flow events.
      PubDate: 2019-02-19
      DOI: 10.1007/s00126-019-00865-9
  • The geochemistry of apatite from the Los Colorados iron oxide–apatite
           deposit, Chile: implications for ore genesis
    • Abstract: Abstract Apatite grains from the Los Colorados iron oxide–apatite (IOA) deposit, the largest IOA deposit in the Chilean Iron Belt (CIB), exhibit significant intracrystalline spatial variability with respect to the concentrations of F, Cl, and OH and trace elements. Statistical interrogation of the compositional data indicates that individual apatite grains contain spatially discrete F-rich and Cl-rich domains. The chemical composition of the F-rich domains is consistent with apatite growth from silicate melts, whereas the chemical composition of the Cl-rich domains is consistent with apatite growth from a magmatic-hydrothermal fluid that cooled as it percolated outward from the Los Colorados fault—the structural control for emplacement of the ore body—into the surrounding brecciated diorite and andesite host rocks. Apatite in the deposit is intimately intergrown with magnetite and actinolite for which trace element, Fe, H, and O stable isotope data indicate a combined magmatic/magmatic-hydrothermal genesis for the deposit. The compositional data for apatite are consistent with a genetic model wherein F-rich apatite cores crystallized with magnetite from silicate melt, followed by exsolution of a magmatic-hydrothermal fluid during decompression of the parent magma. Experimental studies demonstrate that magmatic-hydrothermal volatile phase bubbles preferentially nucleate and grow on the surfaces of apatite and magnetite microlites during decompression of a magma body. Continued degassing of the melt results in the volatile phase sweeping up apatite and magnetite microlites, and forming a magnetite-apatite-fluid suspension that is buoyant in the magma chamber, and ascends from the source magma along faults during regional extension. Halite-saturated fluid inclusions in magnetite, which is paragenetically equivalent to apatite at Los Colorados, indicate that the magmatic-hydrothermal fluid was a brine, which allows this fluid to efficiently scavenge Cl, P, rare earth elements, and other fluid-compatible elements from the silicate melt. During ascent, the XCl/XF ratio of apatite increases as it grows from the evolving Cl-rich magmatic-hydrothermal fluid during decompression and cooling.
      PubDate: 2019-02-15
      DOI: 10.1007/s00126-019-00861-z
  • Neoproterozoic tin mineralization in South China: geology and cassiterite
           U–Pb age of the Baotan tin deposit in northern Guangxi
    • Abstract: Abstract The Baotan tin deposit (23 Mt @ 0.43% Sn) is located in the Jiuwandashan–Yuanbaoshan area, South China. It is hosted in Neoproterozoic mafic/metasedimentary rocks and apical portions of the Pinying granite pluton. Six alteration and mineralization stages have been identified: pre-ore alteration, cassiterite greisen, cassiterite–tourmaline–quartz vein, cassiterite–quartz vein, cassiterite–sulfide vein, and post-ore quartz/calcite–quartz vein stages. Tin mineralization is mainly in the cassiterite greisen, cassiterite–tourmaline–quartz, and cassiterite–quartz vein stages. The deposit is characterized by widespread tourmalinization. Both pre-ore and ore-stage tourmaline is schorl. Tourmaline from pre-ore tourmaline–quartz nodules has elevated Al2O3 and F contents and Fe/(Fe + Mg) and Na/(Na + Ca) ratios, which are probably controlled by the initial magmatic fluid. Ore-stage tourmaline shows low Al2O3 and F contents and Fe/(Fe + Mg) and Na/(Na + Ca) ratios, which are likely influenced by the surrounding mafic rocks. LA–ICP–MS U–Pb dating on two cassiterite samples from disseminated cassiterite–tourmaline–quartz ore and cassiterite–quartz vein yields 206Pb/238U weighted mean ages of 832 ± 5 Ma and 834 ± 4 Ma (2 σ), respectively. These two dates are consistent with the previously reported zircon U–Pb ages of 834–835 Ma for the Pingying granite, which indicates that tin mineralization is related to the granite. The granite has low magnetic susceptibility and zircon Ce4+/Ce3+ ratios, which are similar to those of Sn-bearing ilmenite-series granites. Our study confirms the Neoproterozoic tin mineralization event in South China and indicates that the Neoproterozoic highly fractionated S-type granites in the southeastern margin of Yangtze Block have a great potential for tin mineralization.
      PubDate: 2019-02-08
      DOI: 10.1007/s00126-019-00862-y
  • The polymetallic magmatic-hydrothermal Xiangdong and Dalong systems in the
           W–Sn–Cu–Pb–Zn–Ag Dengfuxian orefield, SE China: constraints from
           geology, fluid inclusions, H–O–S–Pb isotopes, and sphalerite Rb–Sr
    • Abstract: Abstract Vein-type deposits, including the Xiangdong W–Sn and Dalong Pb–Zn deposits, occur in or near the Dengfuxian composite granite pluton, comprising predominantly Triassic and minor Jurassic intrusions. Liquid-rich NaCl-aqueous inclusions, vapor-rich NaCl-aqueous inclusions, liquid-rich CaCl2-NaCl-aqueous inclusions, two-phase CH4-rich inclusions, three-phase CO2-H2O inclusions, and three-phase calcite-bearing inclusions occur in the quartz veins at Xiangdong, whereas only liquid-rich NaCl-aqueous inclusions occur at Dalong. The Xiangdong veins formed at temperatures near 241 °C, from NaCl-CaCl2-H2O-CH4-CO2 fluids averaging 11.4 wt% NaCl eq. The Dalong deposit formed at temperatures near 186 °C from NaCl-H2O(-CH4) fluids averaging 6.2 wt% NaCl eq. The ore-forming mechanisms at Xiangdong include fluid immiscibility during stage I, fluid mixing during stage II, and mixing with meteoric water accompanied by cooling during stage III. The ore-forming mechanisms at Dalong include cooling and mixing with meteoric water. Oxygen and hydrogen isotopes suggest that the ore-forming fluids from both deposits originated as mixtures of magmatic water with various amounts of meteoric water. Sulfur and strontium isotopes suggest an igneous origin for both deposits and possibly mixing with S and Sr from sedimentary rock for Dalong. Lead isotopes indicate that ore metals originated mainly from the upper crust with minor mantle contributions. Sphalerite from Dalong gives a Rb-Sr isochron age of 151.6 ± 7.1 Ma, consistent with the mineralization age of Xiangdong. Both the W–Sn and Pb–Zn ore-forming events are closely related to Late Jurassic magmatism, which occurred in an environment of lithospheric extension and thinning.
      PubDate: 2019-02-05
      DOI: 10.1007/s00126-019-00863-x
  • An introduction to the thematic issue on “Ore deposits in the Variscan
           basement of Central Europe”
    • PubDate: 2019-02-01
      DOI: 10.1007/s00126-018-0860-y
  • Genesis of hydrothermal silver-antimony-sulfide veins of the Bräunsdorf
           sector as part of the classic Freiberg silver mining district, Germany
    • Abstract: Abstract The peripheral regions of the Freiberg vein-type silver mining district comprise several sub-districts of which Bräunsdorf was among the richest in terms of Ag grade. Historically, 114 t (about 3.9 million ounces) of Ag were produced from the Neue Hoffnung Gottes mine near Bräunsdorf. The Neuer Segen Gottes Stehender is a sigmoidally shaped NNE-SSW trending vein, which varies significantly in thickness (0.05 to 3 m) and extends over about 2.6 km strike length at the surface. The vein infill is marked by a Pb-Zn-Cu-Fe-sulfide-quartz (stage 1) and an abundant Ag-Sb-sulfide/sulfosalt-quartz ± carbonate assemblage (stage 2). To develop a sound genetic understanding of the polymetallic mineralisation in the Bräunsdorf sub-district, we conducted detailed textural analyses of ore and gangue minerals, fluid inclusion analyses, electron microprobe analyses and thermodynamic computations in order to characterise the ore fluids and ore-forming processes. The early-stage Pb-Zn-Cu-Fe-sulfide mineralisation (stage 1) is related to fluids with low salinities (0.5–4% eq. w(NaCl)) and formed at temperatures ≥ 300 °C. Microthermometric data related to the Ag-Sb-sulfide/sulfosalt assemblage (stage 2) show similar salinites compared to ore stage 1, but have significantly lower homogenisation temperatures in the range of 180–280 °C. Based on fluid inclusion data, cooling can be regarded as the major ore-forming process. Reaction path model calculations for cooling of fluids with different initial pH values (4, 5.5 and 7) reproduce the observed mineral assemblages very well and predict spatial zonation of the Ag-Sb- and Sb-sulfide minerals that are in excellent agreement with field observations. We conclude that Ag-rich zones may well occur below Sb-rich zones in hydrothermal vein-type systems similar to those of the Freiberg district. This relationship may be of potential use for exploration targeting.
      PubDate: 2019-02-01
      DOI: 10.1007/s00126-018-0842-0
  • Characteristics of the Late Devonian Tsagaan Suvarga Cu–Mo deposit,
           Southern Mongolia
    • Authors: Naidansuren Tungalag; Sereenen Jargalan; Bat-Erdene Khashgerel; Chuluunbaatar Mijiddorj; Imants Kavalieris
      Abstract: Abstract The Late Devonian Tsagaan Suvarga deposit (255 Mt at 0.55% Cu, 0.02% Mo) is located on the NW margin of the Tsagaan Suvarga Complex (TSC), which extends ENE over 15 × 10 km and comprises mainly medium-grained equigranular hornblende-biotite quartz monzonite and monzodiorite. Distinct mineralized intrusions are inferred from distribution of Cu–Mo mineralization but are not clearly discernible. The Tsagaan Suvarga Complex is a window within Carboniferous volcanic and sedimentary rocks, and wall rocks to the TSC are not known or exposed in the nearby district. Whole-rock analyses and Sr–Nd isotopes, 87Sr/86Sr0 = 0.7027 to 0.7038 (n = 12) and εNd0 = + 4.26 to + 2.77 (n = 12), show that the granitoids are subduction-related I-type, high K-calc-alkaline to shoshonitic series and derived from a mantle source. They exhibit fractionated light rare earth elements, without depleted Eu and depleted middle heavy rare earth elements and Y, typical of oxidized, fertile porphyry magmatic suites. Early porphyry-style quartz veins include A- and B-type. Molybdenite occurs in monomineralic veins (1–5 mm) or A veins. Copper mineralization occurs mainly as chalcopyrite and subordinate bornite, disseminated and associated with quartz–muscovite veins. Pyrite (vol%) content is less than chalcopyrite and bornite combined. Deep oxidation to about 50 m depth has formed zones of malachite and covellite in late fractures. The most important alteration is actinolite–biotite–chlorite–magnetite replacing hornblende and primary biotite. Quartz–K-feldspar alteration is minor. Late albite replaces primary K-feldspar and enhances sodic rims on plagioclase crystals. Quartz–muscovite (or sericitic alteration) overprints actinolite–biotite and porphyry-type quartz veins. Field observations and petrographic studies suggest that the bulk of the chalcopyrite–bornite mineralization at the Tsagaan Suvarga formed together with coarse muscovite alteration.
      PubDate: 2018-05-24
      DOI: 10.1007/s00126-018-0812-6
  • The shear zone-related gold mineralization at the Turmalina deposit,
           Quadrilátero Ferrífero, Brazil: structural evolution and the two stages
           of mineralization
    • Authors: Wendell Fabricio-Silva; Carlos Alberto Rosière; Bernhard Bühn
      Abstract: Abstract Turmalina is an important orogenic gold deposit located in the NW region of the Quadrilátero Ferrífero. The deposit is hosted in an Archean greenstone belt composed of ortho-amphibolites and pelites with interleaved tuffs metamorphosed under amphibolite facies conditions and intruded by a granite stock. The orebodies are controlled by WNW-ESE-trending shear zones, associated with hydrothermal alteration. Three deformation events are recognized in the Turmalina gold deposit: D1 and D2 are the result of a progressive Archean deformation under ductile conditions between 2749 ± 7 and 2664 ± 35 Ma; D3 is characterized by a transpressional event under ductile-brittle conditions with the age still unclear. The three generations of garnet observed show that Grt1 blastesis is pre- to syn-D1 and Grt2 growth during the late to post-deformation stages of the D2 event. The initial temperature (Grt1 core) is around 548–600 °C, whereas during late D2, the temperatures reached 633 °C (metamorphic peak–Grt2 rim), likely as a result of granite intrusion. The Grt3 resulted from re-equilibration under retrograde conditions. Two gold-bearing sulfide stages were identified: pyrrhotite-arsenopyrite ± löllingite ± chalcopyrite ± gold stage I precipitated below a metamorphic peak temperature of 598 ± 19 °C associated with S1 foliation (D1), and pyrrhotite-pyrite-arsenopyrite ± chalcopyrite ± gold stage II is located commonly along V3 quartz-carbonate veinlets with a temperature range between 442 ± 9 and 510 ± 30 °C. We suggest that the granite intrusion imposed an additional thermal effect that promoted further dehydration of country rocks. The Au derived mainly from a metamorphic fluid source but potentially mixed with magmatic fluids from the granite.
      PubDate: 2018-05-16
      DOI: 10.1007/s00126-018-0811-7
  • 40 Ar- 39 Ar dating of Archean iron oxide Cu-Au and Paleoproterozoic
           granite-related Cu-Au deposits in the Carajás Mineral Province, Brazil:
           implications for genetic models
    • Authors: Peter J. Pollard; Roger G. Taylor; Lisa Peters; Fernando Matos; Cantidiano Freitas; Lineu Saboia; Sergio Huhn
      Abstract: Abstract 40Ar-39Ar dating of biotite from IOCG and granite-related Cu-Au deposits in the Carajás Mineral Province provides evidence for the timing of mineralization and constraints on genetic models of ore formation. Ages of biotite from greisen and quartz-rich vein and breccia deposits, Alvo 118—1885 ± 4 Ma, Breves—1886 ± 5 Ma, Estrela—1896 ± 7 Ma, and Gameleira—1908 ± 7 Ma, demonstrate the close temporal relationship between Cu-Au mineralization and subjacent A-type granites. Mineralization is hosted within granite cupolas (Breves) or in vein/breccia systems emanating from the cupolas (Estrela and Gameleira), consistent with a genetic relationship of mineralization to the B-Li-F-rich granites. Plateau and minimum ages of biotite from IOCG deposits, including Igarapé Bahia, Cristalino, Corta Goela, and GT34, range from 2537 ± 6 Ma to 2193 ± 4 Ma. The 40Ar-39Ar age of biotite from Igarapé Bahia (2537 ± 6 Ma) is similar to a previous SHRIMP 207Pb-206Pb age for monazite of 2575 ± 12 Ma when the uncertainties in the respective analyses and standards are taken into account. The age spectrum for biotite from Cristalino shows increasing ages for successive steps, consistent with post-crystallization Ar loss, and the age of 2388 ± 5 Ma for the last three steps is considered a minimum age for Cu-Au mineralization. The age of biotite from the GT34 prospect (2512 ± 7 Ma) coincides with a previously identified period of basement reactivation and may indicate the formation of Cu-Au mineralization at this time or resetting of biotite from an older mineralization event at this time. At Corta Goela, within the Canaã Shear Zone, the biotite age of 2193 ± 4 Ma lies between the ages of IOCG (2.57–2.76 Ga) and granite-related Cu-Au (~ 1.88 Ga) deposits elsewhere in the Carajás district but is similar to previously reported 40Ar-39Ar ages for amphibole from Sossego, possibly indicating that mineralization at both Sossego and Corta Goela was affected by a thermal event at this time. The Paleoproterozoic Cu-Au deposits are commonly hosted within Neoarchean IOCG alteration systems and the common occurrence of potassic alteration (especially biotite) in both types of deposits means that special care is required in interpreting the paragenesis of alteration in both types of deposits. The Paleoproterozoic Cu-Au deposits are reduced, and sulfur- and quartz-rich deposits lacking in major amounts of iron oxides and are therefore unlike IOCG deposits. Instead, they share many characteristics in common with widespread Paleoproterozoic Sn-W deposits in the Amazon Craton, including close spatial and temporal relationships with reduced A-type B-Li-F granites, and the occurrence of greisen and quartz-rich vein/breccia systems within and above granite cupolas. The occurrence of sericitic alteration in the Paleoproterozoic Cu-Au deposits is not evidence for an upward transition to sericitic alteration in IOCG deposits in the Carajás Mineral Province.
      PubDate: 2018-05-02
      DOI: 10.1007/s00126-018-0809-1
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