YELLOWSTONE HOTSPOT
Arguably, the most unique
volcano on Earth is the Yellowstone Hotspot. Most centers of volcanic
activity on Earth occur along subduction zones or mid-ocean ridges.
Volcanism also occurs at hotspots. Good examples include the Iceland
Hotspot, the Hawaii Hotspot, and the Yellowstone Hotspot. The behavior of
volcanoes at hotspots varies tremendously. Yellowstone tends to have
tremendously powerful explosive eruptions. The last three major
Yellowstone eruption have a noticeable periodicity of ~600,000 to 650,000
years. Yellowstone's last major ash eruption occurred 640,000 years ago.
The geology of the
Yellowstone Hotspot is readily examined, as the entire area is preserved in a
national park. Yellowstone National Park has the highest concentration of
geothermal features anywhere in the world. The area is famous for its
abundance of geysers, hot springs, fumaroles, etc. The bedrock at
Yellowstone is almost exclusively ash beds & lava flows.