Tag Archive for: geologic

Utah Geological Survey
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News on the Latest UGS Rockfall Investigation in the Zion Area

kcsg.com

Residents living within high rock-fall-hazard zones in Rockville, Utah, face the possible consequences of a large rock fall similar to the fatal event that occurred last December. That is the principle finding of a geologic investigation into the rock fall that killed two people on December 12, 2013. That afternoon, a huge, joint-controlled rock mass, with an estimated volume of almost 1,400 cubic yards and weighing about 2,700 tons, detached from the cliff face at the top of the Rockville Bench, near Zion National Park. The rock mass fell onto the steep slope below the cliff, and shattered into numerous fragments. The rock fall debris then moved rapidly downslope before striking and destroying a house, detached garage, and a car. The largest boulder to strike the house weighed an estimated 520 tons.

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Utah Geological Survey

"Spot the Rock" for Thursday, March 27, 2014

It’s Thursday, and that means “Spot the Rock”!

Can any of you geo-sleuths tell us where this is?

Utah Geological Survey

"Spot the Rock" March 20, 2014

Can you “Spot the Rock”? This tucked away sight is no castle of rocks, though its immensity is quite spectacular.
Like us on FACEBOOK or follow us on TWITTER to participate!

UPDATE: Location Revealed

Last week’s “Spot the Rock” photo was of a sinkhole in Big Round Valley, Washington County, just north of the Arizona state line. Can you spot the person for scale in this closeup view of the sinkhole?

This hole formed when the roof of an underlying cave collapsed, but what created the underlying cave? It was likely created when ground water dissolved and carried away the mineral gypsum. The Harrisburg Member of the Kaibab Formation underlies the sinkhole and is known for such gypsum “karst” features elsewhere in the area. Alternatively, or in conjunction with gypsum dissolution, ground water may have dissolved and carried away part of an underlying limestone layer.

A third possible scenario involves a process called sediment piping, where ground water traveling along initially small cracks carries away clay and silt-size particles. In this scenario, fine sediment is carried away in suspension by flowing ground water, and the small cracks can grow to large channels, or pipes. For piping to occur, the removed silt and clay needs a place to be deposited. Therefore, piping features usually end at the base of a river bank or other steep slope. However, the bed of the adjacent Virgin River is about 20 feet (6 meters) higher in elevation than the bottom of the sinkhole. Thus sediment cannot be piped to the river channel. This brings us full circle to needing a cave in limestone or gypsum bedrock to collect sediment.

More information on this location can be found here-http://geology.utah.gov/surveynotes/geosights/sinkhole.htm

Utah Geological Survey

"Spot the Rock" March 13, 2014

Can you “Spot the Rock”? It’s time for a new mystery geologic location—tell us where these bumpy rocks are found!

Like us on FACEBOOK or follow us on TWITTER to participate!

UPDATE: Location Revealed
For those of you who follow our GeoSights (http://1.usa.gov/1dqnUJo), last week’s “Spot the Rock” was probably very easy. For those who don’t (you should), the answer is Fantasy Canyon.

Fantasy Canyon is approximately an hour’s drive southeast of Vernal. Even though it’s only 28-miles (as the crow flies) in distance, the labyrinth of oil company service roads quickly lengthen the drive.

You’ll find that Fantasy Canyon is crowded with intricate and peculiar stone figures that are a unique expression of rock weathering and erosion. Covering only a few acres, this miniature canyon can be viewed up-close on a short 0.6-mile loop trail. The dull, light khaki gray color of Fantasy Canyon sandstone transforms to a glowing pale orange at sunset. More information about Fantasy Canyon can be found at http://1.usa.gov/1l4cbs7.

Utah Geological Survey

"Spot the Rock" March 6, 2014

Here’s another installment of “Spot the Rock”! Can you guess where this is? Like us on FACEBOOK or follow us on TWITTER to participate!

UPDATE: Location Revealed
Crystal Geyser is located on the eastern bank of the Green River approximately 3.5 miles downstream from Interstate 70. It is a geologically unusual site to visit, as it is a cold-water, carbon-dioxide-driven geyser as opposed to the geothermal geysers you would see at Yellowstone. In the past, Crystal Geyser’s eruptions were notably higher and more frequent than what they are today. As seen in the video the entire area is draped with beautiful travertine (calcium carbonate) which makes it a gem of a place to put on your bucket list.

Utah Geological Survey

"Spot the Rock" February 27, 2014

“Spot the Rock” is back this week with these towering giants. Can you guess where in Utah this feature is found?

Like us on FACEBOOK or follow us on TWITTER to participate in “Spot the Rock”!

Utah Geological Survey

"Spot the Rock" February 20, 2014

It’s time again for another round of “Spot the Rock”! Can you guess where this interesting sight is located?

Like us on FACEBOOK or follow us on TWITTER to participate in “Spot the Rock”!

UPDATE: Location Revealed
This “Spot the Rock” photo was taken in northwestern most part of Utah, at the southern end of the Grouse Creek Mountains, Box Elder County. As was correctly guessed it is in the area of the Devils Playground.

Devils Playground consists of Tertiary-age (approximately 38 million years old) granitic rock formed from a cooling magma body that intruded overlying Paleozoic (400 to 300 million years old) sedimentary rocks. Known as the Emigrant Pass pluton, this intrusion covers an area of approximately 10 square miles. For more information including directions, visit our GeoSights article-http://geology.utah.gov/surveynotes/geosights/devils_playground.htm

Utah Geological Survey

"Spot the Rock" February 13, 2014

It’s Thursday, and time for another “Spot the Rock” challenge! Let’s see how many of you can guess where this is!

Like us on FACEBOOK or follow us on TWITTER to participate in “Spot the Rock”!

UPDATE: Location Revealed

Alhambra Rock is a diatreme seen to the west of Scenic Byway 163 is southeastern Utah just south of Mexican Hat. Explosive Tertiary volcanic events created diatremes, which are volcanic necks or plugs. Small vents erupted pulverized rock and gas from the magma chamber to the earth’s surface. The magma-filled vents cooled and hardened, and were covered by sediments that later eroded. The remaining volcanic necks now stand in stark outline above the surrounding landscape. Diatremes are present along Comb Ridge, and are also in adjacent states, and include the famous Shiprock in northwestern New Mexico. You can read more about the surrounding area in our “Canyon County” pamphlet (pdf) here: http://1.usa.gov/1cqMLQ9

Utah Geological Survey

Learn about geology of old mining area

thespectrum.com

SILVER REEF — The Museum at Silver Reef is sponsoring a “Geology Walk and Talk” Feb. 22 led by geologist Marc Deshowitz. The presentation is free to the public and will begin at 10 a.m. at the Cosmopolitan restaurant next to the museum, 1903 Wells Fargo Road in Silver Reef. The walk will lead to a view of the White Reef, about a half-mile, gently uphill).

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Utah Geological Survey

What are the roots of geobotany?

Plants can enlighten geologists as to the rock beneath. Geobotany, also called phytogeography, is the scientific study of the distribution of plants.

Climate is considered the primary control on plant life, but within a particular climatic region the rock beneath soil—known as the parent material of soil—is typically the key factor influencing the vegetation growing above. Rock ultimately determines soil moisture characteristics, nutrient availability, and concentrations of essential elements.

Therefore, certain plants are associated with specific rock types. Limestone, dolomite, shale, gypsum, chert, gabbro, rock salt, and ultramafic rocks (e.g., dunite, peridotite, serpentinite), for example, are known for their distinctive floras. Since before the advent of agriculture humans have used plants as a guide to find sought-after rocks and minerals. Today, the methodologies of geobotany are still applicable, practical, and even cost-effective to the geologist.

Dramatic changes in vegetation can occur with changes in geology. In mountain ranges of the Great Basin, big sagebrush growing on sandstone abruptly transitions to bristlecone pine on dolomite. The distribution of the California poppy in Arizona closely correlates with copper mineralization, which in turn corresponds with fault lines.

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