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Tin-Amzi granite dome, Ahaggar Mts (Hoggar Mts), Tamanghasset Province, Algeria

Intrusive F/Li/Na/K-rich leucogranite (525-538 My) dome in granulitic gneisses.
Topaz (F)-muscovite (Li) granite in the deep parts of the cupola, topaz-zinnwaldite granite in the upper parts of the intrusion.
Frequent dykes of topaz-muscovite porphyric microgranite above the cupola.
These microgranites show miarolitic cavities with cassiterite (Ta), wolframoixiolite, ferberite and scheelite.
Late tardimagmatic evolution of granites :
- Mobilization (by vapor fluids) of Sn in the miarolitic system.
- Transfer of W (liquid phase) in granites.
- REE are extracted by fluids from the deeper parts of the cupola and reconcentrated at the top of the intrusion.
- Loss of F and Li in topaz-muscovite granites and microgranites (extraction by a liquid phase).





Mineral List:
Albite
Cassiterite
Columbite
Ferberite
Ixiolite
var: Wolframoixiolite

Muscovite
Muscovite
var: Lithian Muscovite

Orthoclase
Quartz
Rutile
Scheelite
Siderite
var: Manganoan Siderite

Topaz
Uraninite
Xenotime-(Y)
Zinnwaldite
Zircon


17 entries listed. 12 valid minerals.

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