6-18-19

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.

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.