blogs.scientificamerican.com
March 23, 1769 marks the birthday of pioneering stratigrapher William Smith, who is also credited with creating the first useful geological map, however like many other great accomplishments also Smith’s idea of depicting the distribution of rocks on a topographic map didn’t materialize out of nowhere.
We can’t say “no” to Monday mornings when they feature both Utah’s red-rock and grand mountains!
Warner Valley, Washington County, Utah
Photographer: Tyler Knudsen; © 2012
Red hues of rippled sands and nearby Sand Mountain (Navajo Sandstone-capped cliff in middle ground) intensify in the lateafternoon sun. The snow-capped Pine Valley Mountains, the eroded remains of a massive Miocene-age igneous intrusion, rise high above the surrounding red-rock desert.
mesquitecitizen.com
Friends of Gold Butte presented its monthly lecture at the Mesquite Community Theatre on March 19, featuring geologist Marc Deshowitz. Having presented several other lectures on geologic history to the group, Deshowitz was literally brought back by “popular demand” of the audience.
By: Charles G. Oviatt
This 20-page report summarizes observations of sediments and shorelines of the Gilbert episode in the Bonneville basin of northwestern Utah. Lake Bonneville dropped to altitudes similar to those of modern Great Salt Lake by 13,000 years ago, remained low for about 1400 years, then rapidly rose about 50 ft (15 m) during the Gilbert episode (about 11,600 years ago). The Gilbert lake was probably less extensive than shown by previous mapping of the Gilbert shoreline. The lake reached altitudes of 4250-4255 ft (1295-1297 m), and its shoreline, which is not well defined anywhere in the basin, was probably not deformed by residual isostatic rebound associated with removal of the Lake Bonneville water load. Holocene Great Salt Lake has not risen as high as the Gilbert-episode lake.
With Spring here, we can’t wait to get back out to some of our favorite places. Here’s a bright photo for the season!
Butler Wash, San Juan River, San Juan County, Utah
Photographer: Michael Vanden Berg; © 2011
Petroglyph panel on Jurassic-age Navajo Sandstone, Butler Wash, San Juan River, San Juan County.
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.
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.
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.
parkrecord.com
Francis resident Eric Averett was sitting at his kitchen table Friday morning when he felt a short rumbling and a “boom” sound. That rumbling was a 3.2-magnitude earthquake, which was reported three miles southwest of Woodland.
The Utah Geological Survey (UGS) is a division of the Utah Department of Natural Resources. Several specialized programs comprise the UGS: Data Management, Energy & Minerals, Geologic Hazards, Geologic Information & Outreach, Geologic Mapping, Groundwater & Wetlands, and Paleontology.
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