POTD April 25, 2017: Yellowstone Basin

Yellowstone Basin, Uinta Mountains, Duchesne County

Photographer: Rich Emerson © 2017

 

POTD April 04, 2017: Modern dunes, Arches National Park

Modern dunes, Arches National Park
Photographer: Kent Brown © 2017

Modern dunes (foreground) consist of sand weathered from bedrock such as the Wingate Sandstone (skyline), which similarly formed from sand deposited in dunes 200 million years ago.

POTD March 28, 2017: Little Cottonwood Canyon, Salt Lake County

Little Cottonwood Canyon, Salt Lake County
Photographer: Adam McKean © 2017

Interbedded shale and quartzite of the Precambrian Big Cottonwood Formation are dramatically folded and faulted on the sheer face of Twin Peaks in Little Cottonwood Canyon. The intrusive Tertiary-age Little Cottonwood granite stock forms the light-gray, glaciated peaks in the distance.

POTD March 21, 2017: Devils Garden Natural Area, Grand Staircase-Escalante National Monument

Devils Garden Natural Area, Grand Staircase-Escalante National Monument

Photographer: Bill Lund © 2017

Metate Arch, formed in the Entrada Sandstone, is a classic example of a caprock natural arch.

POTD March 14, 2017: Big Cottonwood Canyon, Wasatch Range

Big Cottonwood Canyon, Wasatch Range
Photographer: Mike Hylland © 2017

The waters of Lake Blanche reflect Sundial Peak, composed of quartzite of the Big Cottonwood Formation. Rocks in this basin, which formed from sediment that accumulated along a continental margin 900 million years ago, preserve striations (parallel scratches and grooves) that record the down-valley flow of Ice Age glaciers.

POTD February 28, 2017

View east from Jackson Bottom along the Colorado River, Grand County.
Photographer: Brian Butler © 2017

POTD February 21, 2017: Goblin Valley State Park

Goblin Valley State Park

Photographer: Michael Vanden Berg © 2017

Early morning sun casts shadows on “goblins” formed within the Entrada Sandstone, which consists of sediment deposited 160 million years ago in tidal flats and coastal dunes. Erosion forms the goblins, leaving resistant sandstone boulders perched atop softer siltstone and shale layers that erode more quickly.

POTD February 14, 2017: Arches National Park, Grand County

Arches National Park, Grand County
Photographer: Gregg Beukelman © 2017

Defying gravity, an estimated 3500-ton sandstone boulder of Jurassic-age Entrada Formation perches atop a pedestal of less resistant sandstone of the Dewey Bridge Member of the Carmel Formation and forms Balanced Rock at Arches National Park. Snow-capped peaks in the background are the La Sal Mountains, a Tertiary-age laccolith.