“Rocks are records of events that took place at the time they formed. They are books. They have a different vocabulary, a different alphabet, but you learn how to read them.” – John McPhee

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Flaming Gorge National Recreation Area


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Located in Northeastern Utah and Wyoming, it encompasses 1,384,132 acres of National Forest – 1,287,909 in Utah and 96,223 in Wyoming – with elevations ranging from 6,000 to over 13,500 feet.


Flaming Gorge National Recreation Area was established by Congress October 1, 1968. The area contains 207,363 acres of land and water, almost equally divided between Utah and Wyoming.


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Pronghorns of Antelope Flats, Flaming Gorge


In 1869, Major John Wesley Powell, on expedition down the Green River, looked in awe at this magnificent country and named it Flaming Gorge. Today the brilliant red cliffs are scenic attractions for thousands of visitors annually. Managed by the Ashley National Forest Service including the section of the Green River below Flaming Gorge Dam, this rugged wildland stretches from Wyoming high deserts, where herds of antelope play along the lakeshore, to the forested slopes of Utah’s Uinta Mountains.

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Flaming Gorge is famous for its trophy lake trout. Good number of 30+ pound fish are caught each year. The Utah record went 51 lb 8 oz, and there may yet be a bigger one swimming in the reservoir. Fishing is also very good for rainbows, brown trout, kokanee salmon and smallmouth bass.


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Flaming Gorge


Stratigraphy of Flaming Gorge National Recreation Area:


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Petroglyphs have been found, giving evidence that American Indians lived in, or passed through, the area hundreds of years before the first Europeans arrived. To these natives, the Green River was known as the Seeds-ka-dee-a, the Crow Indian word meaning prairie hen.

Petroglyphs and artifacts suggest that Fremont Indians hunted game near Flaming Gorge for many centuries. Later, the Comanche, Shoshoni, and Ute tribes, whose members spread throughout the mountains of present-day Colorado and Utah, visited the Flaming Gorge country.

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South of Green River, UT in Labyrinth Canyon


Labyrinth Canyon is located on the Green River below the town of Green River, Utah. It is one of the best flat-water river sections in the West. Steep red canyon walls, smooth water, wildlife, and solitude are some of the features that you can expect while paddling in this area. There are tremendous hiking opportunities in the side canyons that line the river, with chances to explore stone arches, ancient rock art, and ruins. This section is suitable for paddlers of all abilities.


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Canyonlands is a place of relative geologic order. Layers of sedimentary deposits systematically record chapters in the park’s past. With some exceptions, these layers have not been altered, tilted or folded significantly in the millions of years since they were laid down by ancient seas rivers or winds.

Upheaval Dome is quite a different story. In an area approximately three miles (5km) across, rock layers are dramatically deformed. In the center, the rocks are pushed up into a circular structure called a dome, or an anticline. Surrounding this dome is a downwarp in the rock layers called a syncline. What caused these folds at Upheaval Dome?


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Aerial Upheaval Dome


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When geologists first suggested that Upheaval Dome was the result of a salt dome, they believed the land form resulted from erosion of the rock layers above the dome itself.

When meteorites collide with the earth, they leave impact craters like the well-known one in Arizona. Some geologists estimate that roughly 60 million years ago, a meteorite with a diameter of approximately one-third of a mile hit at what is now the Upheaval Dome. The impact created a large explosion, sending dust and debris high into the atmosphere. The impact initially created an unstable crater that partially collapsed. As the area around Upheaval Dome reached an equilibrium, the rocks underground heaved upward to fill the void left by the impact. Erosion since the impact has washed away any meteorite debris, and now provides a glimpse into the interior of the impact crater, exposing rock layers once buried thousands of feet underground.

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Upheaval Dome


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The rim of Upheaval Dome is 3 miles across and over 1000 feet above the core floor. The central peak in the core is 3000 feet in diameter and rises 750 feet from the floor.

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Green River & Upheaval Dome


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Both origin hypotheses account for the overall structure of Upheaval Dome, assuming approximately a mile of overlying rock has been eroded. The main differences between the two hypotheses are the amount of time and the pressures needed to produce the structure.

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Upheaval Dome area


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In 2007, German scientists Elmar Buchner and Thomas Kenkmann reported finding quartz crystals that were “shocked” by the high pressure of a meteorite impact. Many geologist now consider the mystery of Upheaval Dome’s origin to be solved.

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34 miles around Upheaval Dome


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Stucturally, it’s a dome, but topographically, it’s a crater. Simply stated, the entire structure appears as an eroded, 5.5 km (3.4 mi.) diameter crater surrounded by concentric rings composed largely of siltstone and sandstone. The central portion of the dome is a topographic depression eroded 350 m below the surrounding escarpment, which is ringed by a syncline and breached by a canyon cut through its west wall. The innermost portion of the crater has a central uplift or peak with a complex sequence of folded and faulted strata with an imbrication of thrust slices piled against the central peak and splayed towards the southeast.

Stratigraphically, Permian age White Rim and Cedar Mesa Sandstones of the Cutler Group lie at the center, the oldest exposed rocks of the dome. Upheaval’s rocks are progressively younger from its center to the rim. Like the layers of an onion, outwardly lie Triassic strata of the Moenkopi and Chinle Formations, Jurassic age Wingate Sandstone, Kayenta Formation and Navajo Sandstone. The outer rocks of Upheaval Dome dip outward, anticlinally, in all directions from the central peak. Non-resistant formations such as the Kayenta and the Chinle are eroded into strike valleys that encircle the center. Resistant sandstones stand tall as circular ridges, outermost of which is the Navajo. Upheaval Dome is located within the boundaries of the Paradox basin, and is therein underlain by the salt-bearing Pennsylvanian Paradox Formation.

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muddy stream that drains Upheaval Dome


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The Enigma of Upheaval Dome: Diapiric Salt or Ground Zero?


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Upheaval Dome Geology


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More recently, researchers (Daly and Kattenhorn, 2010) have theorized a combined impact-salt diapiric event. They believe that the deformation styles at Upheaval Dome actually represent a meteorite impact that decreased the pressure of the overlying rocks and subsequently triggered the vertical flowage of salt. Salt flow may have bulged the Paradox Formation later in a ring surrounding the center of the impact without significant salt diapirism. Little is actually known about the effect of a meteorite impact into layers of salt, since this is the only known scenario of such an event.


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Inside Upheaval Dome


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One of my favorite geologists is Wayne Ranney. His blog rocks:


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Filed under Geology, Nature

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