Glad You Asked—Glacial Striations and Slickensides

slickensidesWhat are those groovy rocks and how did they get that way?
Carole McCalla

On a hike around Lake Blanche below Sundial Peak in Big Cottonwood Canyon, a group of hikers came across long, straight, parallel grooves on a smooth, polished rock surface. Recalling another location where they had seen similar features at the foot of the mountains north of downtown Salt Lake City, they wondered if these markings were formed in the same way. Indeed, what exactly are they and how were they formed?

Although the smooth, grooved surfaces at these two locations are similar, they were actually formed in very different ways.

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Calendar of Utah Geology 2010

The 2010 calendar from the Utah Geological Survey is now available. The ‘Calendar of Utah Geology 2010’ features photographs of geologic vistas from around Utah. UGS staff took all of the photos in the Calendar.

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A Tale of Two Breccia Types in the Mississippian Leadville Limestone, Lisbon and Other Fields, Paradox Basin, Southeastern Utah

David E. Eby, Thomas C. Chidsey, Jr., Douglas A. Sprinkel, & Michael D. Laine

Presented at the American Association of Petroleum Geologists annual convention, Denver, CO, June 2009.

ABSTRACT

Breccia associated with sediment-filled cavities is relatively common throughout the upper third of the Mississippian Leadville Limestone in Lisbon and other fields, Paradox Basin, southeastern Utah. These cavities or cracks are related to karstification of the Leadville during exposure in Late Mississippian time. Infilling of the cavities by detrital carbonate and siliciclastic sediments occurred before deposition of the Pennsylvanian Molas Formation. The transported material consists of poorly sorted detrital quartz grains, chert fragments, and clasts of carbonate and clay. The carbonate muds infilling the karst cavities are very finely crystalline and non-porous dolomites.

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The Gothic Shale at Greater Aneth Oil Field, Paradox Basin, Southeastern Utah: Seal for Hydrocarbons and Carbon Dioxide Geological Sequestration

Thomas C. Chidsey, Jr., Stephanie Carney, Jason Heath, and Thomas Dewers

Presented at the American Association of Petroleum Geologists annual convention, Denver, Colorado, June 9, 2009.

ABSTRACT

Greater Aneth oil field, Utah’s largest oil producer, was discovered in 1956 and has produced over 451 million barrels (bbls) of oil. Located in the Paradox Basin of southeastern Utah, Greater Aneth is a stratigraphic trap producing from the Pennsylvanian Paradox Formation. Because it represents an archetype oil field of the western U.S., Greater Aneth was selected to demonstrate combined enhanced oil recovery (EOR) and carbon dioxide (CO2 ) sequestration. The Aneth Unit in the northwestern part of the field has produced 149 million bbls of the estimated 450 million bbls of OOIP—a 33% recovery rate. The large amount of remaining oil made the Aneth Unit ideal to demonstrate both CO2 storage capacity and EOR by CO2 flooding.

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Basin-wide evaluation of the uppermost Green River Formation's oil shale resource, Uinta Basin, Utah and Colorado

greenriver_fm1 Michael D. Vanden Berg, Utah Geological Survey
Presented at the AAPG Annual Conference, Denver, CO, June 2009

ABSTRACT

Due to the recent increase in crude oil prices and concerns over diminishing conventional reserves, the Utah Geological Survey has reexamined the Uinta Basin’s oil shale resource, primarily in the Mahogany zone of the Green River Formation. We created conversion equations by correlating available Fischer assays with corresponding density and sonic measurements as a way to predict oil yield from geophysical logs. In addition to the core-based Fischer assays obtained from 107 wells drilled specifically for oil shale, 186 oil and gas wells with oil yields calculated from digitized bulk density or sonic logs were used to create a basin-wide picture of the oil shale resource in the Uinta Basin. These widespread data were used to map oil shale thickness and richness and create isopach maps delineating oil yields of 15, 25, 35, and 50 gallons of shale oil per ton (GPT) of rock. From these isopach maps, new basin-wide resource numbers were calculated for each richness grade.

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USEP Hoping to Direct Funding to Utah's Local Governments

The Utah State Energy Program (USEP) has been allocated almost $9.6 million from the U.S. Department of Energy’s (DOE) Energy Efficiency and Conservation Block Grant (EECBG). Dr. Jerriann Ernstsen, manager of the EECBG program, urges local governments to start planning now to help prevent communities from missing the funding opportunity application period, which will have a very narrow window of time to apply. The project types will focus on energy efficiency retrofits, on-site renewable energy systems, traffic and street lighting, and other related projects.

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Energy Efficiency and Conversation Block Grant

Utah State Energy Program Awarded $14.1 Million

Utah has been awarded $14.1 million today, toward an eventual sum of $35 million. “Utah is one of 10 states to receive millions of dollars for energy efficiency and renewable energy projects from the U.S. Department of Energy’s (DOE) Recovery Act,” said Jason Berry, manager of the Utah State Energy Program.

Energy Secretary Steven Chu today announced more than $204 million in Recovery Act funding. In order to be eligible for funding from DOE’S State Energy Program (SEP), states must have proposed statewide plans that prioritize energy savings, create or retain jobs, increase the use of renewable energy, and reduce greenhouse gas emissions. This initiative is part of the Obama Administration’s national strategy to support job growth, while making an historic down payment on clean energy and conservation.

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American Recovery and Reinvestment Act (Recovery Package)

GeoSight— Wall Arch, a Fallen Giant

geosights-wall-arch-beforeDuring the night of August 4, 2008, Utah lost a popular giant when Wall Arch, a prominent arch along the Devils Garden Trail in Arches National Park, collapsed.

While not the largest or most famous arch in the park, Wall Arch was still a favorite due to its proximity to Landscape Arch along the always-busy trail. With a measured span of 55 feet, it was ranked as 12th largest in the park (some publications and Web sites give the span as 71 feet – this is actually the “breadth”, a dimension that is not useful for comparing arches).

While no arch lasts forever, it is still extremely rare to see such a dramatic example of “geology in action.” We do not have a good geologic tool for dating arch formation, but we are sure that Wall Arch had stood nearly unchanged for hundreds, and probably thousands of years.

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GeoSight— Fantasy Canyon

geosights-fanatsy-canyonGeologic Information: The sandstone layer in which the pinnacles, pillars, arches, and knobs of Fantasy Canyon are formed consists of ancient river channel sediments. The underlying and overlying rock layers sandwiching the sandstone layer, and creating scenic badland topography around the canyon, are finer grained floodplain deposits.

During the Eocene Epoch, 55 to 34 million years ago, the Fantasy Canyon area was at the fringe of a vast subtropical lake – Lake Uinta – that at peak level stretched from the Wasatch Plateau to western Colorado. The lake was in a drying phase and retreating westward by the end of the Eocene.

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GeoSight— Cascade Springs

cascade-springsGeologic Information: The area around Cascade Springs is underlain by coarse-grained glacial sediment deposited when glaciers covered high elevations of the Wasatch Range approximately 30,000 to 10,000 years ago.

Beneath the glacial deposits, bedrock consists of Cambrian-age (about 500 million years old) quartzite, shale, sandstone, and limestone. These rocks were transported eastward 30 to 50 miles during low-angle faulting on the Charleston-Nebo thrust fault around 80 million years ago. As a result of the faulting, the bedrock in the vicinity of the springs is tilted and highly fractured.

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