(Köfels, Umhausen, Ötztal, Nordtirol, Tirol, Österreich)
Landslide (8000 years ago), with ductile deformation at very high strain rate in a narrow shear zone: intense friction raised temperature to melting, leading to the formation of a pumiceous glass thin layer.
The glass resulted from friction thermometamorphism of biotite-amphibole gneisses and not from volcanism or shock.
Ref.:
Eur. J. Mineral., 1993, 5, 893-902.
Mineral List: |
'Glass'  | | | | Reference: | [Eur. J. Mineral. , 1993, 5, pp. 893-902.] |
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Lechatelierite | | | | Reference: | [R. Exel: Die Mineralien und Erzlagerstätten Österreichs (1993)] |
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'Pumice' | | | | Reference: | [Eur. J. Mineral. , 1993, 5, pp. 893-902.] |
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Quartz | | | | Description: | Presents numerous undulatory extinctions, dislocation loops, subgrain boundaries, dislocation in climb configuration forming junctions, and also evidence of lattice friction. | | Reference: | [Eur. J. Mineral. , 1993, 5, pp. 893-902.] |
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4 entries listed. 1 valid mineral.
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