Wednesday, July 28, 2010

Lava flows in Arizona

This is where Wikipedia is way off. In the article on a list of lava flows in Arizona, the poster says, "there are three lava flow areas in the American state of Arizona." Wrong. There are dozens, perhaps hundreds of lava flows throughout the state. Some of the most prominent geological features in the state are associated with lava flows. Here is a NASA photo of one of the flows, very near to Sunset Crater and the Bonita Lava Flow shown above.

This is the Black Point Lava Flow in northern Arizona, seen in this photograph taken from the International Space Station. The flow is part of Arizona’s San Francisco Volcanic Field, a group of geologically young (approximately six million to less than one thousand years old) volcanoes, lava flows, and cinder cones located just north of Flagstaff, Arizona. NASA.

As you travel throughout the state, you will see many old and new lava fields. One prominent section is located near the town of Springerville and is known as the Springerville Volcanic Field. The Springerville volcanic field is a monogenetic volcanic field located in east-central Arizona, USA. The field consists of 405 discrete vents covering approximately 3,000 square kilometers (1,200 sq mi) and is the third largest such field in the continental United States, only the San Francisco volcanic field (Arizona) and Medicine Lake volcanic field (California) are larger. Wikipedia.

There is also the Uinkaret Volcanic Field in the Grand Canyon National Park which has been instrumental in creating one of the notable rapids along the Colorado River, Lava Falls. Vulcan's Throne on the rim of the Canyon is a Quaternary cinder cone.

Quoting from the USGS, Arizona Volcanoes and Volcanics, "Late Cenozoic lava flows have repeatedly flowed down Toroweap Valley and several adjacent valleys into the Grand Canyon, at times forming large lava dams. Flows are exposed on the walls of the Grand Canyon, often interbedded with fluvial and lacustrine sediments, up to 600 meters above present river level. Several of the dams are estimated to have been at least 200 meters high. The most recent flows in the Grand Canyon have cascaded over the rim of the Esplanade to the river 1,000 meters below. "

Some of the other notable features of the Arizona landscape that resulted from volcanic activity include the famous Superstition Mountains, the Chiricahua National Monument, the White Mountains and of course, the San Francisco Mountains.

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