Earth Science Picture of the Day

Photographer: Ronald Smith
Summary Author: Ronald Smith

The photo above shows Pine Valley Mountain in southwestern Utah as viewed from 12th hole of Sunriver Golf Course. Pine Valley Mountain is one of the largest laccoliths in the United States. A laccolith forms as thick, viscous lava intrudes between two sedimentary rock layers. The intrusion bends the strata upward, forming a mushroom shaped mountain. Erosion frequently carves canyons and exposes the once buried igneous rocks, often granite or diorite. Ironically, the granite rock in the foreground here was quarried from Pine Valley Mountain.

The headwaters of the Santa Clara River are on Pine Valley Mountain. The St. George area is sometimes called "Utah's Dixie" because water from this river permitted Mormon pioneers to grow cotton during the U.S. Civil War. Photo taken on February 13, 2013.

Photo details: Nikon d3200 camera; Nikkor 85mm f/2 lens, stopped to f/22; ISO 1600; 1/100 sec exposure. A polarizing filter was used to bring out contrast and color saturation.

• St. George, Utah Coordinates: 37.0953, -113.5781
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