slgwv's photos with the keyword: ash-flow tuff

At the north end of the Wah Wah Mountains in western Utah. It's composed entirely of the Tunnel Spring Tuff of early Tertiary age. Cavernous weathering is prominent! For scale the larger bushes are full-sized Utah junipers.

An improbable peak at the north end of the Wah Wah Mountains in western Utah. From a distance in bright sunlight the peak appears completely white! It's composed of the Tunnel Spring Tuff, a large ash-flow tuff unit of early Tertiary age (about 35 million years). The extreme thickness here probably reflects filling of an ancient valley near the caldera vent. The insets are close-up views showing prominent cavernous weathering. For scale, the little green plants on the mountain slopes are full grown Utah junipers, like those in the foreground!

At the north end of the Wah Wah Mountains in western Utah. It's composed entirely of the Tunnel Spring Tuff of early Tertiary age. Cavernous weathering is prominent! For scale the larger bushes are full-sized Utah junipers. The rusty outcrops in the right foreground are of the Eureka Quartzite, a much older (Ordovician) unit. The mechanical contrast between the Eureka and the enclosing limestones probably provided a channel for the eruption of the tuff.

Back toward the camera position in the enclosing photo. Painted Hills, north of Reno, Nevada.

Natural arches in volcanic rock (rhyolitic ash-flow tuff) in the Painted Hills, north of Reno, Nevada. This unit is notable for cavernous weathering! Insets show (left) a close-up of the lower window; and (right) a view back out this window looking toward this camera location.

Close-up of the lower window in an ash-flow tuff unit in the Painted Hills, north of Reno, Nevada.