(Minas da Panasqueira, Panasqueira, Covilhã, Castelo Branco, Portugal)
A tin-tungsten mine.
Panasqueira granite intrudes Precambrian marine shales, greywackes and sandstones.
Shales are converted into biotite cordierite andalusite hornfelses near the granite contact.
Irregular barren quartz masses were formed in shales (quartz segregation lenses) during Hercynian regional metamorphism.
Panasqueira muscovite-albite leucogranite batholith evolves upwards into a quartz-greisen cupola overlain by a quartz cap, from which related quartz veins (stockscheider) penetrate into the shales.
Later subhorizontal mineralized veins follow these quartz veins.
Four stages of mineralization are known:
1) Oxide-silicate stage (280-320°C): wolframite, cassiterite in quartz veins, arsenopyrite, topaz, muscovite and tourmaline
2) Sulfide stage: arsenopyrite, pyrite, pyrrhotite, chalcopyrite, sphalerite, stannite, etc.
3) Pyrrhotite alteration stage
4) Carbonate stage: calcite and dolomite, minor sulfides
References:- Mineral. Rec. (1971) 2 (2), 73-78.
- Bull. Minéral., 1988, 111, 251-256
- Bull. Minéral., 1984, 107, 703-713.
- Werner, A.B.T., Sinclair, W.D., and Amey, E.B. (1998): International Strategic Mineral Issues Summary Report - Tungsten. US Geological Survey Circular 930-O.
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http://www.fc.up.pt/geo/ecrofi/263.PDF
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http://www.panasqueira.net/
For further refs., see also 'Panasqueira'.
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Map Reference: 40°9'N , 7°45'W
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Mineral List:66 entries listed. 61 valid minerals. 2 type localities (valid minerals).
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