Lithogeochemical studies of aureoles around the panasqueira tin-tungsten deposit, portugal

Oosterom, M.G.; Vriend, S.P.

doi:10.1007/bf00204381

Cited by 15 publications

(3 citation statements)

References 6 publications

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“…In general, high-grade lodes comprise variable amounts of wolframite or cassiterite, sulfides (typically chalcopyrite, arsenopyrite, sphalerite, pyrrhotite, pyrite, stannite, galena, and Bi-Ag-bearing phases) and Bi alloys [57,58,62,126]. Alongside these lodes, alteration haloes affecting the hosting metasediments are usually observed, extending up to 2 m away from the thicker lodes and characterized by intense deposition of tourmaline, along with accessory white mica ± chlorite [59,127,128].…”

Section: The Panasqueira Depositmentioning

confidence: 99%

“…A new (short-lived?) rejuvenation event took place after the "main sulfide stage", as indicated by Ms II + Tpz II + Apt II (± Cst II ± Wolf II) formation, followed by some sulfides (including molybdenite) [127]. Temperature conditions for the onset of this event are provided by the Ms II-Tpz II pair (≈ 440-450 • C), which are consistent with the growth of a late arsenopyrite at 437 ± 27 • C [121,204], both preceding Chl II (≈ 250-270 • C) and the progression towards the final carbonate post-ore evolution stage.…”

Section: Evolution Of Temperature Conditionsmentioning

confidence: 99%

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Relative Abundance and Compositional Variation of Silicates, Oxides and Phosphates in the W-Sn-Rich Lodes of the Panasqueira Mine (Portugal): Implications for the Ore-Forming Process

et al. 2020

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Panasqueira is a world-class W-Sn-Cu lode-type deposit located in Portugal. It consists of a dense swarm of subhorizontal quartz lodes criss-crossed by several ENE–WSW and N–S fault zones, bordering Late Variscan granite and hosted in Late Ediacaran—Early Cambrian metasediments. The relative abundance and compositional variation (assessed with EPMA) of the main silicates, oxides and phosphates forming the quartz lodes and their margins were examined, aiming to explore: (i) mineral and geochemical zonation at the mine scale; and (ii) some conclusions on the chemical nature of prevalent fluid inflows and T-conditions of mineral deposition. Quartz lodes nearby or far from the known greisen-granite cupola display significant differences, reflecting multiple fluid influxes of somewhat distinct composition related to various opening and closing events extending for several My, ranging from an early “oxide–silicate stage” (OSS) to a “main sulfide stage” (MSS), and further on to a post-ore carbonate stage (POCS); however, a rejuvenation event occurred after MSS. The onset of OSS was placed at ca. 299 ± 5 Ma and the rejuvenation event at ca. 292 Ma. The OSS was confined to ≈500 ≤ T ≤ 320 °C, following rutile and tourmaline growth under ≈640 ≤ T ≤ 540 °C (depending on aSiO2). The rejuvenation event (≈440–450 °C) preceded a late chlorite growth (≈250–270 °C) and the progression towards POCS.

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Section: The Panasqueira Depositmentioning

confidence: 99%

Section: Evolution Of Temperature Conditionsmentioning

confidence: 99%

Relative Abundance and Compositional Variation of Silicates, Oxides and Phosphates in the W-Sn-Rich Lodes of the Panasqueira Mine (Portugal): Implications for the Ore-Forming Process

et al. 2020

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“…There is some parallelism between geochemical concentrations in host rocks and further away from the Argemela deposit and what happens in Panasqueira, where the hydrothermally altered Beira Slates hosting the quartz W-Sn-Cu veins are characterized by K 2 O/Rb (wt/wt) < 250 and are enriched in Rb, K, Cs, Li, W, Cu, Zn, Sn, S and P relative to unaltered Beira Slates (BUSSINK, 1984;OOSTEROM et al, 1984;POLYA, 1989). The mean W, Cu and Sn concentrations decrease irregularly away from the Panasqueira cupola, with anomalous concentrations up to about 10 km away from it (POLYA, 1989).…”

Section: Rock Analysesmentioning

confidence: 99%

The granite-related, high-tonnage Sn-Li deposit of Argemela, central Portugal

Inverno¹,

Ferraz²,

Moreira³

et al. 2019

Cad Lab Xeol Laxe

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The Argemela Sn-Li quartz vein stockwork, east of the Panasqueira tungsten mine, is hosted in Cambrian slates and greywacke. An underlying Variscan granitic cupola is inferred from spotted slates and albitic microgranite dykes, the last including a thick modified albitic microgranite, enriched in F and Li, exposed some 500 m away, on the hill top. Inferred resources for shallowest deposit portion are 20.1 million tonnes (Mt) at 0.1-0.2% Sn, 0.2% Li and 0.1% (estimate) Rb, but the 650-m vertical-extent of the deposit suggests a resource of >200 Mt (with identical grades). The hydrothermal paragenetic sequence is amblygonite-montebrasite (mostly montebrasite) (Stage I)–quartz I-II–cassiterite (with columbite-tantalite inclusions)─arsenopyrite I─carbonate I-white mica I ─chlorite I–fluorite–apatite–rutile (Stage II)– white mica II–molybdenite– tourmaline– carbonate II-quartz III–arsenopyrite II–sphalerite–stannite–chalcopyrite–pyrite– pyrrhotite-chlorite II (Stage III)–covellite– vivianite–goethite/lepidocrocite (Stage IV). Amblygonite-montebrasite is the main Li carrier; Sn is evenly distributed between cassiterite and stannite; Rb is mostly in white mica (with 0.25-1.23 wt % Rb2O in the hill-top albitic microgranite). Primary aqueous, 1-3 um-wide fluid inclusions in the deposit in quartz I, carbonate I, apatite and cassiterite growth zones yield overall salinities and homogenisation temperatures of 7.2-19.1 wt % NaCl equiv. and 290-360ºC, respectively. The trace concentrations (electronic microprobe analysis) in quartz vein cassiterite reach 1.95 wt % Nb, 0.39 wt % Fe, 0.13 wt % Ti, and low/negligible values of Sb, Zn, As, Ag and Bi showing its granite-hydrothermal affiliation. Fe-poor and Fe-rich sphalerite (lower-intermediate and upper deposit parts) contain 1.0-1.6 and 7.9-9.4 wt % Fe, 64.3-66.0 and 55.9-57.2 wt % Zn, 0.4-0.5 and 0.9-1.1 wt % Cd, respectively. The sphalerite-stannite geothermometer yields temperatures of 245-297ºC. Following higher temperature amblygonite-montebrasite deposition (Stage I), hydrothermal fluids (aCl-=0.25 m), related to the hidden granitic cupola, at a mean pressure-corrected (50 MPa) temperature of 350ºC, were responsible for Stage II minerals deposition. Calculated cassiterite deposition from Sn chloride complexes occurred likewise, from probable magmatic-hydrothermal fluids, at fO2 = 10-34 -10-32 atm and pH=3.5-4. Cassiterite deposition mechanisms were oxidation, mixing, neutralisation, possible aCl- increase, and cooling. Later Fe-poor sphalerite (+kesterite/ferrokesterite) and Fe-rich sphalerite (+stannite) deposited at higher and lower fS2, respectively, the latter probably at a higher fO2 (Stage III). The uniqueness of Argemela system with abundant amblygonite-montebrasite in hydrothermal quartz tin veins may be related to an extreme fractionated F-, Li- and P-rich granitic magma. After the emplacement of the granite/albitic microgranite dykes, an emerging pegmatitic fluid was unable, possibly due to insufficient depth, to form pegmatites but only modified the hill-top albitic microgranite. As a consequence, the system, where mixing of high- and low-salinity magmatic fluids probably occurred, remained very enriched in F, Li and P and by the time the hydrothermal stockwork developed amblygonite-montebrasite (Stage I) was the first mineral to deposit abundantly before Stage II minerals deposition in those Argemela Sn-Li quartz veins.

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The W Deposit at Panasqueira (Portugal)

MARIGNAC,

CATHELINEAU

2023

Metallic Resources 1

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Lithogeochemical studies of aureoles around the panasqueira tin-tungsten deposit, portugal

Cited by 15 publications

References 6 publications

Relative Abundance and Compositional Variation of Silicates, Oxides and Phosphates in the W-Sn-Rich Lodes of the Panasqueira Mine (Portugal): Implications for the Ore-Forming Process

Relative Abundance and Compositional Variation of Silicates, Oxides and Phosphates in the W-Sn-Rich Lodes of the Panasqueira Mine (Portugal): Implications for the Ore-Forming Process

The granite-related, high-tonnage Sn-Li deposit of Argemela, central Portugal

The W Deposit at Panasqueira (Portugal)

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