User:Team5DTVanessa/sandbox

Lead section
My contribution on: Draft:Silly Mountain (Arizona)

Contribution
Site: https://repository.arizona.edu/bitstream/handle/10150/630781/ofr-95-9.pdf

"Rhyolite--Crystal-poor, light tan lavas containing less than 2% anhedral to subhedral phenocrysts of clear to light grey plagioclase and fresh black biotite in a light tan to light pink aphanitic matrix. Locally flow-banded and rarely vitrophyric. Well exposed west of Dinosaur Mountain and at Silly Mountain where the unit forms steep, rounded, resistant hills.

"Dacite--Contains subhedral 1-15 mm phenocrysts of clear to light grey plagioclase and subhedral to euhedral 1-8 mm phenocrysts of biotite and hornblende in a dark maroon to blue-purple aphanitic matrix. The unit is crystal-rich, containing about 20-25% phenocrysts. Exposures near Dinosaur Mountain are fresh and locally vitrophyric. They also contain thin layers of yellow bedded tuff. At Silly Mountain flow-banding within the unit is parallel to flow-banding in the surrounding rhyolite.

In Silly Mountain is present a mineral, Rhyolite, a tan volcanic rock in the form of steep and rounded hills. The flow-banding of this mineral is parallel to that of Dacite, another type of volcanic rock, rich in crystals, and with about 20-25% of phenocrysts.

Team5DTVanessa (talk) 19:51, 17 November 2022 (UTC)