POTD July 29, 2013: Lake Mountains, Utah County, Utah

Lake Mountains, Utah County.
Photographer: J. Lucy Jordan

UGS geologists provide oversight and run downhole geophysical logs during ground-water monitoring-well drilling.

POTD July 26, 2013: San Rafael Swell, Emery County, Utah

San Rafael Swell, Emery County, Utah
Photographer: Taylor Boden

Boulders of Cretaceous-age Ferron Sandstone, eroded from the top of a distant butte, have come to rest on the Cretaceous-age Mancos
Shale on the west flank of the San Rafael Swell.

POTD July 25, 2013: Slickrock Trail near Moab, Grand County, Utah

Slickrock Trail near Moab, Grand County, Utah
Photographer: Jim Davis

Giant weathering pits or potholes like this one (about 16 feet across at the bottom) in the Jurassic-age Navajo Sandstone typically form along fractures and joints atop fins, knolls, and rounded domes. Potholes are created through a combination of physical, chemical, and biological processes that weather and erode the rock and are home to a remarkable array of ancient aquatic organisms.

POTD July 24, 2013: Grand Staircase–Escalante National Monument, Kane County, Utah

Grand Staircase–Escalante National Monument, Kane County, Utah
Photographer: Tyler Knudsen

The narrow defile of Round Valley Draw exposes layers of ancient petrified dunes of the Jurassic-age Navajo Sandstone. This is one of numerous slot canyons in Utah’s canyon country formed by the scouring action of infrequent but powerful flood waters.

POTD July 23, 2013: Trilobite, House Range, Millard County, Utah

 

Trilobite, House Range, Millard County, Utah
Photographer: Michael Vanden Berg

Cambrian-age shales from western Utah’s House Range contain millions of fossilized trilobites, such as this specimen of Elrathia kingi.

POTD July 22, 2013: Mount Timpanogos, Wasatch Range, Utah County, Utah

Mount Timpanogos, Wasatch Range, Utah County, Utah
Photographer: Jason Berry

Thousands of years of precipitation, wind, and glacial erosion have sculpted the east face of the Mount Timpanogos massif. The steep cliffs and snow-covered ledges of the Oquirrh Formation exposed on Roberts Horn (10,953 feet) are reminiscent of the Canadian Rockies.

POTD July 19, 2013: San Rafael Reef, Emery County, Utah

San Rafael Reef, Emery County, Utah
Photographer: Tom Chidsey

The steeply dipping east flank of the San Rafael Swell is part of a large fold that formed in Late Cretaceous to early Tertiary time.

POTD July 18, 2013: Wasatch-Cache National Forest, Weber County, Utah

Wasatch-Cache National Forest, Weber County, Utah
Photographer: Ken Krahulec

Prominent cliffs of gently dipping Mississippian-age Deseret (upper) and Gardison (lower) Limestone are exposed along the walls of Ogden Canyon. These strata are part of a thrust sheet emplaced during the Sevier orogeny, a regional mountain-building event that affected much of western Utah between about 140 and 50 million years ago.

POTD July 17, 2013: Crystal Geyser, Green River, Grand County, Utah

Crystal Geyser, Green River, Grand County, Utah.
Photographer: Taylor Boden

Colorful travertine (calcium carbonate) is deposited around cold-water, carbon-dioxide-driven Crystal Geyser.

POTD July 16, 2013: Dixie National Forest, Kane County, Utah

Dixie National Forest, Kane County, Utah
Photographer: Tyler Knudsen

Golden aspen, blue sky, and dark basaltic lava provide dramatic contrast along the Navajo Lake Loop Trail on the Markagunt Plateau. The geologically young Quaternaryage lava erupted from a nearby cinder cone and flowed across Duck Creek, creating a natural dam that formed Navajo Lake.