• a_geologistMagma Monday: Dark, basaltic lava flow erupted from a cinder cone (in lower left). Cinder cones are relatively small, short-lived volcanoes (life span a few months to a few years only) of basaltic composition. During the cone building phase, a lot of gases (water and CO2 mostly) cause the eruption to be somewhat explosive, producing a lot of fragmental material, like cinder. But after the gases are lost, the magma loses its fizz and then tends to come out as non-explosive lava flows, as seen here. (Diameter of cone about 1 km. San Francisco volcanic field north of Flagstaff, Arizona. Image from Google Earth)

The Chapel of the Holy Dove, a few miles north of Flagstaff, Arizona, is an icon of the area around the Grand Canyon. Open to the public and free to visit at the side of Highway 180, it was built by Dr. Watson Lacy in the 1960s of local ponderosa pine, lava rock, and petrified wood from the nearby prehistoric forests. The chapel forbids writing prayers on the walls, but this hasn’t stopped people–their pleas to God and the saints cover every inch of the interior, all the way up to the ceiling.