Island Park Caldera
From Wikipedia, the free encyclopedia
The Island Park Caldera is one of the world's largest calderas at 18 miles (29 km) long and 23 miles (37 km) wide. It is in eastern Idaho just to the southwest of the Yellowstone Caldera. It was formed in an eruption of more than 280 cubic kilometers 1.3 million years before present (BP), on top of another caldera created in a much larger eruption (2500 cubic kilometers) 2.1 million years BP. These eruptions also formed the Mesa Falls Tuff and the Huckleberry Ridge Tuff respectively.
To the southwest of the caldera lies the Snake River Plain that was formed by a succession of older calderas in the path of the Yellowstone hotspot. The Henrys Fork of the Snake River drains the area, dropping out of the caldera at Upper and Lower Mesa Falls. The caldera is bounded by the Ashton Hill on the south, Big Bend Ridge and Bishop Mountain on the west, by Thurburn Ridge on the North and by Black Mountain and the Madison Plateau on the east.
The caldera is in an area called Island Park and is famous for its beautiful forests, large springs, clear streams, waterfalls, lakes, ponds, marshes, wildlife, and fishing. Harriman State Park is situated in the caldera. Snowmobiling, fishing, and nordic skiing, and wildlife viewing are popular activities in the area. The peaks of the Grand Tetons are visible looking southeast from places in the caldera.
