Timing of native metal-arsenide (Ag-Bi-Co-Ni-As±U) veins in continental rift zones – In situ U-Pb geochronology of carbonates from the Erzgebirge/Krušné Hory province

Guilcher, Marie; Albert, Richard; Gerdes, Axel; Gutzmer, Jens; Burisch, Mathias

doi:10.1016/j.chemgeo.2021.120476

Cited by 11 publications

(3 citation statements)

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“…There were 50-80 s of gas background data collected prior to each ablation. Data were corrected for the following interferences: 65 CuH + on 66 Zn + , 63 Cu 40 Ar + on 103 Rh + , 65 Cu 40 Ar + on 105 Pd + and 115 Sn + on 115 In + . The exact argide and hydride formation rates were determined by ablating elemental Cu (linescan, 60-120 s, 32 µm, 5 J cm −2 ).…”

Section: Methodsmentioning

confidence: 99%

“…Panafrican to Variscan magmatic and/or metamorphic ores followed by later sedimentary brine circulation and base metal-precious metal deposition during the Mesozoic are typical features of most Anti-Atlas deposits, including the Zgounder (Ag-Hg), Bou Azzer (Co-Ni-Ag-Au) and Imiter (Ag-Hg) deposits [97][98][99][100] and the Jebilet deposits (Roc Blanc, Koudia El Hamra and Jbel Haïmer). In base metal-precious metal-fluorite-barite vein deposits, reactivated faults hosted Paleozoic and Mesozoic mineralization in the Erzgebirge and Schwarzwald vein deposits coeval with sedimentary brines related to continental rifting [93,[101][102][103].…”

Section: Ore Brines-jebilet Vein Depositsmentioning

confidence: 99%

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Polymetallic Sulfide–Quartz Vein System in the Koudiat Aïcha Massive Sulfide Deposit, Jebilet Massif, Morocco: Microanalytical and Fluid Inclusion Approaches

et al. 2022

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The Koudiat Aïcha Zn-Cu-Pb deposit (3–Mt ore @ 3 wt.% Zn, 1 wt.% Pb, 0.6 wt.% Cu) in the Jebilet massif (Morocco) comprises stratabound lenticular orebodies and crosscutting sulfide-bearing quartz ± carbonate veins in the lower Carboniferous Sarhlef volcano sedimentary succession. The veins are characterized by abundant pyrrhotite, sphalerite, subordinate chalcopyrite and galena and rare Ag and Au minerals. The stratabound massive sulfide ores are attributed to a “VMS” type, whereas the origin of the sulfide–quartz ± carbonate veins remains poorly understood. New mineralogical and microanalytical data (SEM, EPMA and LA-ICP-MS) combined with fluid inclusion results point to two-stage vein formation. The early stage involved C–H–O–N Variscan metamorphic fluids which percolated through fractures and shear zones and deposited pyrite at >400 °C, followed by the formation of pyrrhotite and sphalerite (300 ± 20 °C) in quartz veins and in banded and breccia ores. The pyrrhotite–sphalerite mineralization was overprinted by aqueous brines (34 to 38 wt% eq. NaCl + CaCl2) that precipitated carbonate and Cu-Pb sulfides (±Ag-Au) at ~180–210 °C through mixing with low-salinity fluids during tectonic reworking of early-formed structures and in late extension fractures. The latter ore fluids were similar to widspread post-Variscan evaporitic brines that circulated in the Central Jebilet. Overlapping or successive pulses of different ore fluids, i.e., metamorphic fluids and basinal brines, led to metal enrichment in the quartz–carbonate veins compared to the massive sulfide ores. These results underscore that even a single deposit may record several distinct mineralizing styles, such that the ultimate metal endowment may be cumulative over multiple stages.

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Section: Methodsmentioning

confidence: 99%

Section: Ore Brines-jebilet Vein Depositsmentioning

confidence: 99%

Polymetallic Sulfide–Quartz Vein System in the Koudiat Aïcha Massive Sulfide Deposit, Jebilet Massif, Morocco: Microanalytical and Fluid Inclusion Approaches

et al. 2022

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“…The Erzgebirge/Krušné hory region (Fig. 1A) is a classic metallogenic province that hosts late-Paleozoic magmatichydrothermal systems such as greisen (Štemprok, 1967;Baumann and Tischendorf, 1976), skarn (Hösel, 2003;Burisch et al, 2019;Reinhardt et al, 2021), and epithermal vein-type mineralization (Swinkels et al, 2021) as well as Mesozoic hydrothermal five-element-and fluorite-barite-vein systems (Kuschka, 1972;Guilcher et al, 2021;Haschke et al, 2021;Burisch et al, 2022). The Erzgebirge comprises a series of metamorphic nappes that developed during the Variscan orogeny in Central Europe (i.e., the collision of Laurussia and Gondwana; Kroner et al, 2007;Linnemann and Romer, 2010).…”

Section: Regional Geologymentioning

confidence: 99%

The Spatial and Temporal Evolution of the Sadisdorf Li-Sn-(W-Cu) Magmatic-Hydrothermal Greisen and Vein System, Eastern Erzgebirge, Germany

Leopardi,

Gutzmer,

Lehmann

et al. 2024

Economic Geology

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The Sadisdorf Li-Sn-(W-Cu) prospect in eastern Germany is characterized by vein- and greisen-style mineralization hosted in and around a small granite stock that intruded into a shallow crustal environment. The nature and origin of this mineral system are evaluated in this contribution by a combination of petrography and fluid inclusion studies, complemented by Raman spectroscopy and whole-rock geochemical analyses. The early magmatic-hydrothermal evolution is characterized by a single-phase low-salinity (7.0 ± 4 wt % NaCl equiv), high-temperature (>340°C), CO2-CH4–bearing aqueous fluid, which caused greisen alteration and mineralization within the apical portions of the microgranite porphyry. The bimodal distribution of brine and vapor fluid inclusions, and the formation of a magmatic-hydrothermal breccia associated with the proximal vein mineralization are interpreted to mark the transition from lithostatic to hydrostatic pressure. The vein- and stockwork-style mineralization (main stage) displays lateral zonation, with quartz-cassiterite-wolframite-molybdenite mineral assemblages grading outward into base-metal sulfide-dominated assemblages with increasing distance from the intrusion. Late fluorite-bearing veinlets represent the waning stage in the evolution of the mineral system. The similarity in the homogenization temperature (250°–418°C) of fluid inclusions in quartz, cassiterite, and sphalerite across the Sadisdorf deposit suggests that cooling was not a significant factor in the mineral zonation. Instead, fluid-rock interaction along the fluid path is considered to have controlled this zonation. In contrast to quartz-, cassiterite- and sphalerite-hosted fluid inclusions, which have a salinity of 0.0 to 10.0 wt % NaCl equiv, the fluid inclusions in late fluorite veins that overprint all previous assemblages have a salinity of 0.0 to 3.0 wt % NaCl equiv and homogenize at temperatures of 120° to 270°C, thus indicating cooling with or without admixture of meteoric fluids during the waning stage of the mineral system. The Sadisdorf deposit shares similar characteristics with other deposits in the Erzgebirge region, including a shallow level of emplacement, similar mineralization/alteration styles, and a hydrothermal evolution that includes early-boiling, fluid-rock interaction, and late cooling. In contrast to most systems in the region, both proximal and distal mineralization are well preserved at Sadisdorf. The recognition of such spatial zoning may be a useful criterion for targeting greisen-related Li and Sn resources.

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Timing and origin of skarn-, greisen-, and vein-hosted tin mineralization at Geyer, Erzgebirge (Germany)

Meyer,

Markl,

Gerdes

et al. 2023

Miner Deposita

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This contribution presents new insights into the origin and age relationships of the Geyer tin deposit in the Erzgebirge, Germany. Tin mineralization occurs in skarns, greisen, and in cassiterite-bearing fluorite-quartz veins. Skarn alteration replaces marble layers of the Cambrian Jáchymov Group and occurs in two clearly distinct stages. The first skarn stage forms skarnoid textured assemblages of clinopyroxene, garnet, and wollastonite with no tin phases recognized. Garnet U-Pb ages of this skarn stage (~322 Ma) relate the earlier skarn stage to the emplacement of the Ehrenfriedersdorf granite (~324 to 317 Ma). The second stage of skarn alteration is marked by the occurrence of malayaite and cassiterite associated with garnet recording ages of 307 to 301 Ma. Greisen- and skarn-hosted cassiterite-bearing veins provide U-Pb ages in the range of 308 to 305 Ma, relating greisenization and vein formation to the same magmatic-hydrothermal event as the second skarn stage. This suggests that tin mineralization at Geyer is related to a distinctly younger magmatic-hydrothermal event, clearly postdating the Ehrenfriedersdorf granite, which was previously assumed as the source of the tin-rich fluids. Fluid inclusions show salinities in the range of 1.0 to 31.5 % eq. w(NaCl±CaCl2) and homogenization temperatures between 255 and 340 °C. Cassiterite-associated fluid inclusions show indications for heterogeneous entrapment and dilution of hydrothermal with meteoric fluids. Dilution of high-salinity fluids with low-salinity fluids and cooling of the system was probably a decisive process in the precipitation of cassiterite in the Geyer Sn system.

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Timing of native metal-arsenide (Ag-Bi-Co-Ni-As±U) veins in continental rift zones – In situ U-Pb geochronology of carbonates from the Erzgebirge/Krušné Hory province

Cited by 11 publications

References 56 publications

Polymetallic Sulfide–Quartz Vein System in the Koudiat Aïcha Massive Sulfide Deposit, Jebilet Massif, Morocco: Microanalytical and Fluid Inclusion Approaches

Polymetallic Sulfide–Quartz Vein System in the Koudiat Aïcha Massive Sulfide Deposit, Jebilet Massif, Morocco: Microanalytical and Fluid Inclusion Approaches

The Spatial and Temporal Evolution of the Sadisdorf Li-Sn-(W-Cu) Magmatic-Hydrothermal Greisen and Vein System, Eastern Erzgebirge, Germany

Timing and origin of skarn-, greisen-, and vein-hosted tin mineralization at Geyer, Erzgebirge (Germany)

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