petrology, volcanology

Flow-banded rhyolite

Rhyolite is an igneous, extrusive volcanic rock high in silica forming typically in continental arc settings. The flow-banding in this sample is caused by the friction of the viscous magma in contact with a solid rock surface or by compaction, causing flattening and welding of shards and pummice. [Be prepared for pictures of a bunch… Continue reading Flow-banded rhyolite