San Francisco Volcanic Field - Al Hann

Northern Arizona - October 2008

The San Francisco Volcanic Field

Flagstaff lies near the Southern edge of the San Francisco Volcanic Field. The area contains some 600 volcanoes, which were active between 6 million and 1000 years ago.

View Larger Map	Here is a shaded relief map of the area, showing a swath about 40mi across (West to East). The vast majority of the "bumps" are volcanic in origin. While most are old cinder cones and lava domes (generally milder eruptions), the large structure just below/left of center is the remains of an old stratovolcano (explosive eruptions) known as the San Francisco Peaks. One of them, "Humphreys Peak", is the highest point in Arizona at 12,633ft. Flagstaff is at bottom center.
	Some old volcanic features that dot the entire region. Note the tall "saw grass" in the foreground. While northern Arizona is a very arid region, the San Francisco Volcanic Field runs from this type of terrain, to Ponderosa Pine forests at higher elevations.
	More cinder cones in the distance, only here the elevation is a little higher. The foreground trees are some sort of pine, around 10-15ft tall.
	An abandoned quarry area along a U.S. Forest Service road. While the area was badly littered with trash, note the black wall of the quarry. This give the idea of the composition of these volcanic features.

Sunset Crater Volcano National Monument

Sunset Crater Volcano National Monument is a short ride north on US-89 from Flagstaff. I visited this park a couple of times during the trip.

	This is Sunset Crater, the most recently active volcano in the area (formed about 1000yrs ago). According to the National Park Service, there is evidence that the area was inhabited by Native Americans at the time. The evidence also suggests that the local peoples had enough warning to evacuate the area with their belongings.
	The hill on the left is the south slope of Sunset Crater. The black rock in the foreground (bottom), ia actually a pahoehoe-type lava flow (just like the type of lava flows experienced in Hawaii).
	More lave flows (foreground) and old cinder cones (background).
	A look across the "Cinder Hills" area near Sunset Crater. The black area in the immediate foreground is the consistency of coarse beach sand.

The San Francisco Peaks

The view along a small service road paralleling I-40, looking north-east.

The north slope of the San Francisco Peaks. Here we are looking south-west.

A few days earlier, the mountains were completely enshrouded in clouds. It must have snowed up there that day, and here we see some on the higher slopes.

Petrified Forest

Grand Canyon

San Francisco Volcanic Field

Sedona and Red Rock Area

Native American Ruins

Moonrises

Odds & Ends

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