San Francisco volcanic field
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The San Francisco volcanic field is an area of volcanoes in northern Arizona, USA. The field covers 1800 square miles (4700 km2) the southern boundary of the Colorado Plateau. The field contains 600 volcanoes less than 6 million years old, including Sunset Crater, which erupted less than 1000 years ago. The highest peak in the field is San Francisco Mountain, a stratovolcano near Flagstaff, Arizona, that rises to 12,633 feet of elevation.
The volcanic field seems to have formed from a geological hotspot, a hot area in the mantle. As the North American plate moves over the spot, new volcanoes appear. Thus, the newest volcanoes are at the east side of the field. Most of the volcanoes are basalt cinder cones, but there are dacite domes.
The volcanic field is not near San Francisco, California and should not be confused with that city.
External link and source
- USGS fact sheet about the San Francisco volcanic field (http://wrgis.wr.usgs.gov/fact-sheet/fs017-01/).