Lava from Mount Rainier
These dacite samples from Mount Rainier are 93,500 years old. Their columnlike structure is the result of its rapid cooling against a glacier. Dacite is a characteristic lava of subduction-zone volcanoes, and has a composition between those of basalt and rhyolite, the volcanic equivalent of granite.
Loaned by Mount Rainier National Park
Topic: Earth Science
Keywords: Dacite, Lava, Rainier, Mount (Wash.)