GeoSnaps - Image of the Day
Geologic snapshots capturing Arizona’s geologic setting and mining history with a picture of the day from 1 January through 31 December 2013.
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October 2, 2013 | San Franciso Volcanic Field | Northern Arizona
Panorama of the east and central part of the San Francisco volcanic field taken at 16,000’ by Ted Grussing. In the left lower quadrant you can see Sunset Crater - small, red, cinder cone - which is the latest of the volcanoes in the field to erupt.Sunset erupted around 1085 AD. Sunset is surrounded by smaller, eroded cinder cones mantled by black cinders from Sunset's eruption.
The lighter colored mountain to the right of Sunset Crater is O'Leary Peak - a rhyolitic-dacitic dome complex emplaced about 170,000 years ago. In the middle ground, above and to the left of Sunset, is the dacitic Mt Elden volcanic dome, which hovers over Flagstaff. To the right of Mt Elden is San Francisco Mountain, a stratovolcano and the largest volcanic center in the entire field. It formed over about a 1 million year period beginning about 1.2 million years ago. The small bright white splotches at the base of the San Francisco Mountain volcanic complex are pumice quarries. In the distant far ground lies Mingus Mountain and above that Towers Mt, both are situated in Arizona's Transition Zone. (Photo by Ted Grussing)