Tag Archive for: geology

Utah Geological Survey

The Pony Express Basaltic Ash: A Stratigraphic Marker In Lake Bonneville

By: Charles G. Oviatt and Barbara P. Nash

The Pony Express basaltic ash is locally a useful stratigraphic marker in Lake Bonneville sediments in west-central Utah. The ash was erupted from a vent in the Sevier Desert basin soon after Lake Bonneville had transgressed high enough to flood into the basin about 24,000 years ago. The ash is found at or near the base of the Bonneville marl below altitudes of 1400m (4600 ft) in part of the Sevier Desert basin and the southernmost part of the Great Salt Lake basin. The chemical composition of the ash is similar to that of other basalts in the Sevier Desert. Possible source vents are in the Pahvant Butte area or a maar near Smelter Knolls.

This CD contains a 10-page report in PDF format. The latest version of Adobe Reader is required to view the PDF files.

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Utah Geological Survey

Geologic Map of The Brian Head Quadrangle, Iron County, Utah

By: Peter D. Rowley, Robert F. Biek, Edward G. Sable, Jonathan T. Boswell, Garrett S. Vice, Stanley C. Hatfield, David J. Maxwell, and John J. Anderson

The Brian Head Quadrangle straddles the west edge of the Markagunt Plateau and is roughly centered on Brian Head Peak, at 11,307 feet (3446 m) the highest mountain in southwestern Utah. The peak, encompassing an area of great natural beauty and recreational use, is capped by volcanic rocks that erupted from calderas on the Utah-Nevada border. These volcanic rocks overlie landslide-prone local volcaniclastic strata, which in turn overlie colorful strata of the Claron Formation, centerpiece of Cedar Breaks National Monument in the southwest corner of the map area. The plateau is capped by remnants of the 20-million-year-old Markagunt Megabreccia, Utah’s largest catastrophic gravity slide.

This CD contains geographic information system (GIS) files in ESRI file geodatabase and shapefile formats. Two plates, a geologic map at 1:24,000 scale and an explanation plate, and a 38-page booklet are also included in PDF format. The latest version of Adobe Reader is required to view the PDF files.

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Utah Geological Survey

POTD January 29, 2014: Uinta Basin, Uintah County, Utah

Uinta Basin, Uintah County, Utah
Photographer: Michael Vanden Berg

The exceedingly rare Graham’s penstemon grows exclusively on the sparsely vegetated outcrops of Green River Formation oil shale deposits and can be found only in the Uinta Basin of Utah and the Piceance Creek Basin in Colorado. Federal protection for this scarce plant could be forthcoming as petroleum development becomes more prevalent in the basin.

Utah Geological Survey
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Mag. 4.1 quake leads off two dozen earthquakes 37 miles from St. George

stgeorgeutah.com

A swarm, or cluster, of 24 earthquakes have been recorded Tuesday, the first about 37 miles west-northwest of St. George in Nevada, and the others within about a 10-mile radius of the first, see map inset. The earthquakes have ranged from local magnitude 4.1 at both 8:20 a.m. PST and 6:30 p.m. PST, and various lesser amounts throughout the day with the most recent registering local magnitude 3.2 at 6:38 p.m. PST.

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And another great article on Utah quakes and other worldly shakes—
decodedscience.com
Nevada and Utah Earthquakes; Greece, Mid-Atlantic Tremors: January 2014

The world seemed to wake up this week, seismically speaking.

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Utah Geological Survey

Geologic Hazards of the State Route 9 Corridor, La Verkin City to Town of Springdale, Washington County, Utah

By: Tyler R. Knudsen and William R. Lund

Historically, the communities of La Verkin, Virgin, Rockville, and Springdale have been affected by a variety of geologic hazards. Recent damaging rock falls, riverine floods, recurrent flash floods and landslides, and problems associated with collapsible soil and expansive soil and rock demonstrate that the communities are vulnerable to geologic hazards, and that public officials require reliable hazard information as they plan for future growth. The Utah Geological Survey has prepared GIS-based information on the kinds and locations of geologic hazards that may affect existing and future development in the State Route 9 Corridor Geologic-Hazard Study Area (SR-9 study area). The SR-9 study area encompasses 97 square miles, and consists of a 2- to 8-mile-wide corridor centered on SR-9, that extends from the eastern part of La Verkin City to the Town of Springdale’s eastern boundary with Zion National Park.

This 13-page report includes nine 1:24,000-scale geologic-hazard maps that cover flooding and debris flows, rock fall, landslides, surface faulting, liquefaction, collapsible soil, expansive soil and rock, gypsiferous soil and rock, soil piping, erosion, and wind-blown sand. Each geologic-hazard map provides information on the data sources and techniques used to create the map, the nature and distribution of the hazard, and possible hazard-reduction measures.

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Utah Geological Survey

Rockfall in Termeno, Italy

Hey geo friends! Check out this dramatic youtube short of a rockfall in Termeno, Italy. It really shows the expanse of destruction a rockfall can cause.

WATCH HERE

MORE INFORMATION on rock-falls and other hazards in Utah

Utah Geological Survey

POTD January 28, 2014: Cliff Lake, western Uinta Mountains, Summit County, Utah

Cliff Lake, western Uinta Mountains, Summit County, Utah
Photographer: Don Clark

Cliff Lake, seen above in midday light, is located adjacent to the larger Wall Lake and near the base of Mount Watson.

Utah Geological Survey

POTD January 27, 2014: Pittsburg Lake, Utah County, Utah

Pittsburg Lake, Utah County, Utah
Photographer: Sonja Heuscher

Pittsburg Lake, a glacial tarn formed in a cirque carved into the Cambrian-age Tintic Quartzite in upper American Fork Canyon, Utah County.

Utah Geological Survey

New Study Shakes Up Science On Midwest Quake Zone

upr.org

One of the biggest earthquakes in U.S. history didn’t occur in California. Or Alaska. It happened in the country’s midsection some 200 years ago in an area where today seven states straddle the Mississippi River Valley.

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Utah Geological Survey

Grand Canyon May Be Older (And Younger) Than You Think

npr.org

In recent years geologists have hotly debated the age of the Grand Canyon. Some think it’s young (just 6 million years old), while others argue that it dates back 70 million years — to the days of dinosaurs.

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