West Thumb Geyser Basin
The West Thumb Geyser Basin is the largest geyser basin on the shores of Yellowstone Lake in Yellowstone National Park . The Potts Basin in the north is also part of the West Thumb Geyser Basin.
The heat source of the hydrothermal objects in this area is about 3000 m deep, relatively close to the earth's surface. The basin was formed by an eruption of the Yellowstone volcano about 125,000–200,000 years ago. Later, the resulting caldera filled with water, expanding Yellowstone Lake. The West Thumb Basin is about the size of Crater Lake in Oregon , but much smaller than the Yellowstone Caldera, which was formed at the same location when the volcano erupted 600,000 years ago. It is thus a caldera within a larger caldera.
When the underground magma chamber bulged, ring-shaped fractures formed, which allowed the magma to escape. It is still the source of heat for the West Thumb Geyser Basin today.
The hydrothermal objects of this region are not only found on the lakeshore, but also spread out under the lake. Several underwater geysers were discovered in the 1990s . They can be recognized as a slight bulge in the water in summer and as molten holes in the ice in winter. On average, the ice on Yellowstone Lake is about four inches thick in winter.
See also
Web links
- Overview of the West Thumb area (Engl.)
Coordinates: 44 ° 25 '2.2 " N , 110 ° 34' 17.2" W.