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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November 10, 2013 | Chiricahua Mountains, Cochise County - by Wayne Ranney
In the far southeast corner of Arizona, the Chiricahua Mountains rise almost 10,000 feet above sea level and nearly 5,000 feet above the Sulphur Springs Valley to the west. They are part of the “sky island” landscape of southern Arizona where long lines of rock have been faulted upwards into mountain ranges that rise above down-thrown basins - now filled with gravel and sand eroded from the nearby ranges. A small section of the Chiricahuas have been preserved in Chiricahua National Monument, where an early Miocene volcanic caldera and outflow tuffs are spectacularly exposed. This photo is taken on the Echo Canyon Trail and looks to the west toward the outflow tuffs that were welded during eruption some 26.9 Ma. Flattened pumice fragments called fiamme within the tuff give it a crudely bedded look when weathered. In the middle distance is the Sulphur Springs Valley with the Dragoon Mountains on the far horizon, part of which is composed of early Miocene intrusive granite (27 to 22 Ma).