Airfall pumice (~1065 A.D. eruption of Medicine Lake Volcano's Glass Mountain eruptive center, northern California, USA)
Pumice from the Holocene of California, USA. (pale-colored pumice at upper right is 2.7 cm long)
Medicine Lake Volcano is a shield volcano in far-northern California, USA. It is associated with the Cascade Range of stratovolcanoes. The Cascade Range stretches from northern California to Oregon to Washington State, and into southwestern British Columbia. It formed by subduction of the Juan de Fuca Plate underneath the North American Plate. Medicine Lake Volcano has erupted a variety of materials that include basalt, andesite, rhyolite, dacite, obsidian, and pumice.
The rocks shown here are airfall pumice pieces from a ~1065 A.D. eruption at the Glass Mountain eruptive center, on the eastern side of Medicine Lake Volcano.