Special POTD submission, August 29, 2013: Fremont Indian State Park, Sevier County, Utah.

Despite the lingering heat, another summer in Utah is coming to a close. The canyons will soon be ablaze with fall colors and the valleys won’t be far behind. In this spirit we have selected another photo from Gerard Dauphinais to give us a little taste of fall. This photo was taken near Fremont Indian State Park, located in west Sevier County. The park is famous for containing many instances of Fremont Indian rock art.

The Sevier Formation contains most of the major rock outcrops seen in the park. A notable feature of the Sevier Formation is the 19-million-year-old Joe Lott Tuff. This tuff (a welded is a welded volcanic-ash) was produced by an explosive volcanic eruption. The massive eruption created the Mount Belknap caldera located about 10 miles south of Clear Creek Canyon. The surface of the originally white, pink, and gray tuff has weathered to darker colors and serves as a “blackboard” for Fremont Indian rock art.

In this picture we see some of the sedimentary rocks that overly the Joe Lott tuff. The rest of the Sevier River Formation consists of sandstones, siltstones, conglomerates,  and additional volcanic ashes, and lava flows that were deposited about 5 to 14 million years ago, when the present topography of the Basin and Range area began forming. The Sevier River Formation was uplifted and tilted around 5 million years ago.

Thanks again for the great photo Gerard! Click through for the full resolution image and click here for more information on Fremont Indian State Park. Remember, you can always submit your photos to us at ugssmedia@gmail.com, on Facebook, or on Twitter.

POTD August 29, 2013: Notch Peak, House Range, Millard County, Utah

Notch Peak, House Range, Millard County, Utah
Photographer: Michael Vanden Berg

Abundant trilobite fossils, including  Elrathia kingi shown here, can be found  within the Wheeler Shale east of Notch Peak in the House Range.

Many of the dry desert peaks of western Utah tell a story of shallow tropical seas. As much as 500 million years of deep burial, uplift, and erosion have changed layers of organic mud to cliffs and ledges of layered limestone. Closer inspection reveals abundant fossils, evidence of ancient sea life.

POTD August 28, 2013: Notch Peak National Natural Landmark, House Range, Millard County, Utah

Notch Peak National Natural Landmark, House Range, Millard County, Utah
Photographer: Matt Affolter

Cambrian- to Ordovician-aged carbonate rocks (limestone and dolomite) make up Notch Peak, where a 2,200-foot cliff (possibly the tallest carbonate cliff in North America) leads to a deep canyon on the west side of the peak. Pink, Jurassic-aged granite is exposed at the foot of the mountain, and scattered deposits of white, clayey marl deposited in Lake Bonneville during the late Pleistocene are present on the valley floor.

POTD August 27, 2013: Dinosaur Tracks near Moab, Grand County, Utah

Near Moab, Grand County, Utah
Photographer: Carole McCalla

During Jurassic time, a sauropod walked across mud, sinking deeply into it. The footprints can be seen preserved in the rock near Moab in Grand County. BLM interpretive site.

POTD August 26, 2013: Hanksville-Burpee Quarry, Wayne County, Utah

Hanksville-Burpee Quarry, Wayne County, Utah
Photographer: James I. Kirkland

Not a logjam, but a “legjam” of dinosaur bones left in a channel of Jurassic-aged river is being excavated at the Hanksville-Burpee Quarry in Wayne County. BLM interpretive site.

Special POTD submission, August 23, 2013: Henry Mountains viewed through Summerville Formation hills, Emery, Wayne, & Garfield Counties

This photo was submitted to us by Dennis Udink. You can see the Henry Mountains viewed through Summerville Formation hills near the Little Wild Horse road (Goblin Valley area in Emery county).

The Henry Mountains were formed around 31 to 25 million years ago when partially molten rock, from the Earth’s interior, forced its way into overlying sedimentary rocks forming huge domes called laccoliths. Subsequent erosion has exposed the igneous rocks which make up the high peaks of the mountains. Mt Ellen is one of Utah’s highest peaks (outside the Uinta Mountains) at 11,522ft.  The domed and arched sedimentary rocks form the flanks of the range.

One of the more notable inhabitants of the range are the Henry Mountains Bison Herd, which wildlife scientists believe to be only one of four free-roaming, genetically pure bison herds in North America.

Great photo Dennis! Remember, you can always submit photos to the Utah Geological Survey at ugssmedia@gmail.com, on Facebook, or on Twitter.

POTD August 23, 2013: Poison Strip area, east of Arches National Park, Grand County, Utah

Poison Strip area, east of Arches National Park, Grand County, Utah
Photographer: Don DeBlieux

A geologist examines a sequence of Early Cretaceous-aged paleosols (ancient soils) in the Yellow Cat Member of the Cedar Mountain Formation. Many dinosaur fossils are found in these rocks, and the study of paleosols can provide valuable
information about the environments in which these dinosaurs lived.

POTD August 22, 2013: Bluffs above Wahweap Bay on Lake Powell, Kane County, Utah

Bluffs of Entrada Sandstone above Wahweap Bay on Lake Powell, Kane County, Utah
Photographer: Lance Weaver

One of the most photographed geologic formations in Utah if not the world, the Entrada Sandstone is the featured rock unit of Arches National Park, Goblin Valley State Park, Kodachrome Basin State Park, and parts of Glen Canyon National Recreation Area. Variations in the Entrada’s appearance across the state are due to differences in internal structure and composition as well as external stresses.

POTD August 21, 2013: Kodachrome Basin State Park, Kane County, Utah

Kodachrome Basin State Park, Kane County, Utah
Photographer: Carole McCalla

Sand pipe of Carmel Formation sediment intruded into the overlying Entrada Sandstone. One of the most photographed geologic formations in Utah if not the world, the Entrada Sandstone is the featured rock unit of Arches National Park, Goblin Valley State Park, Kodachrome Basin State Park, and parts of Glen Canyon National Recreation Area. Variations in the Entrada’s appearance across the state are due to differences in internal structure and composition as well as external stresses.

POTD August 20, 2013: Temple of the Sun, Capitol Reef National Park, Wayne County, Utah

Temple of the Sun, Capitol Reef National Park, Wayne County, Utah
Photographer: Michael Vanden Berg

Two of Capitol Reef National Park’s popular attractions: Glass Mountain (foreground) and Temple of the Sun (background). Glass Mountain is a large exposed mound of selenite gypsum that formed within the Jurassic-aged Entrada Sandstone. The “gypsum plug” became exposed as the relatively soft Entrada Sandstone eroded away. Temple of the Sun is a large monolith that was also created by erosion of the Entrada Sandstone.