Question

Composite volcanoes such as Mount Rainier in Washington are formed from _____.

Answer 1

Composite volcanoes like Mount Rainer in Washinton are formed from andesitic magma. Composite volcanoes are formed by alternating layers of ash and lava. These volcanoes are typically found at subduction zones. Andesite lavas cool to form fine grained rich in plagioclase feldspar minerals.

Answer 2

Mount Rainier is the highest mountain in the Cascade Range of the Pacific Northwest. This mountain was not formed in one great cataclysm but was made through many years of volcanic activity. Several volcanoes have been erupting in the region for at least 40 million years.