Vitrophyre
Photographed by Michael P. Klimetz
MEXICO
Photographed by Michael P. Klimetz
[Glassy with White Sanidine Phenocrysts]
Thomas Range
Juab County
UTAH
Photographed by Michael P. Klimetz
[Glassy with White Sanidine Phenocrysts]
Thomas Range
Juab County
UTAH
Photographed by Michael P. Klimetz
[Glassy with White Sanidine Phenocrysts]
Thomas Range
Juab County
UTAH
Photographed by Michael P. Klimetz
[Glassy with White Sanidine Phenocrysts]
Thomas Range
Juab County
UTAH
Vitrophyre is a volcanic rock with a porphyritic texture in which larger crystals (phenocrysts) are embedded in a glassy groundmass. A vitrophyre forms when a hot volcanic deposit (e.g. ash-flow tuff, rhyolite flow) comes into contact with the (relatively) cold Earth surface. This sharp temperature gradient results in rapid cooling (or quenching) of the lowest part of the volcanic deposit, forming a glassy basal vitrophyre.
