Tag Archive for: DNR

Can you “Spot the Rock”? This tucked away sight is no castle of rocks, though its immensity is quite spectacular.
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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

By: Tyler Knudsen, Paul Inkenbrandt, William Lund, Mike Lowe, and Steve Bowman

This 116-page report presents the results of an investigation by the Utah Geological Survey of land subsidence and earth fissures in Cedar Valley, Iron County, Utah. Basin-fill sediments of the Cedar Valley Aquifer contain a high percentage of fine-grained material susceptible to compaction upon dewatering. Groundwater discharge in excess of recharge (groundwater mining) has lowered the potentiometric surface in Cedar Valley as much as 114 feet since 1939. Groundwater mining has caused permanent compaction of fine-grained sediments of the Cedar Valley aquifer, which has caused the land surface to subside, and a minimum of 8.3 miles of earth fissures to form. Recently acquired interferometric synthetic aperture radar imagery shows that land subsidence has affected approximately 100 mi² in Cedar Valley, but a lack of accurate historical benchmark elevation data over much of the valley prevents its detailed quantification. Continued groundwater mining and resultant subsidence will likely cause existing fissures to lengthen and new fissures to form which may eventually impact developed areas in Cedar Valley. This report also includes possible aquifer management options to help mitigate subsidence and fissure formation, and recommended guidelines for conducting subsidence-related hazard investigations prior to development.

Although this product represents the work of professional scientists, the Utah Department of Natural Resources, Utah Geological Survey, makes no warranty, expressed or implied, regarding its suitability for a particular use. The Utah department of Natural Resources, Utah Geological Survey, shall not be liable under any circumstances for any direct, indirect, special, incidental, or consequential damages with respect to claims by users of this product.

GET IT HERE

kutv.com

Two Highland men who sang and danced as they toppled an ancient rock formation in Goblin Valley State Park pleaded guilty to charges reduced from felonies to misdemeanors in an Emery County courtroom Tuesday.

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Bear Lake, Rich County, Utah
Photographer: Jim Davis; © 2011

Storm waves deposit tiny snail and clam shells on a sand bar at Rendezvous Beach State Park, south shore of Bear Lake, Rich County.

White Cliffs, Kane County, Utah
Photographer: Tyler Knudsen; © 2011

Small, dome-shaped load structures on a block of Jurassic-age Carmel Formation, White Cliffs, western Kane County.

Tyler Knudsen, one of our geologists here at Utah Geological Survey, talks about our new publication discussing the geologic hazards of the State Route 9 Corridor.

ksl.com

The state has released a new set of maps designed to tip off developers and homeowners to potential geological hazards in communities near Zion National Park.

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LISTEN TO INTERVIEW with Tyler Knudsen

Happy Saint Patrick’s Day! This photo may not be green, but I-rish I was there!

Caineville, Wayne County, Utah
Photographer: Robert Ressetar; ©2011

Deltaic sandstone of the Emery Member caps the Blue Gate Member of the Mancos Shale, deposited in a sea during the Cretaceous Period, Caineville, Wayne County.

Have a fun and safe weekend, everyone!

Hovenweep National Monument, San Juan County, Utah
Photographer: Ken Krahulec; ©2011

Ancient Anasazi dwellings built with blocks of Cretaceous-age Dakota Sandstone at Hovenweep National Monument, southeastern San Juan County.

sltrib.com

If the thought of a 2,700-ton boulder rolling through your house concerns you, the Utah Geological Survey has a new report you might want to read, particularly if you are considering moving to a community along State Road 9 in Washington County.

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Significant Hazards on State Route 9 Near Zion National Park
kcsg.com

There are significant geologic hazards present along State Route 9, between La Verkin and Springdale in Washington County, according to the Utah Geological Survey (UGS). Geologists recently released a comprehensive report addressing the numerous geologic hazards that threaten the growing communities of La Verkin, Virgin, Rockville, and Springdale. All of the communities are on State Route 9 which is the main transportation corridor for more than 2.5 million annual visitors to Zion National Park. “Recent damaging and fatal rock falls in Rockville, landslides in Springdale, and floods along the Virgin River demonstrate that many of the geologic processes that have shaped this area’s outstanding scenery also make this area prone to geologic hazards,’ says Tyler Knudsen, UGS geologist.

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

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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.