Upheaval Dome, the most peculiar structural feature in southeast Utah

Severely contorted innards of Upheaval Dome.

Last September I visited two anomalous features on the generally orderly Colorado Plateau. The first was a cluster of igneous peaks in a sedimentary setting, to be the subject of a later post. I'm starting with the second—a large round hole in the ground. I thought it would be simpler.

The Colorado Plateau covers c. 130,000 sq mi in the Four Corners region in the southwest USA. For the last six million years it has been slowly rising, and yet it's remarkably stable, with limited deformation (NPS). Its wonderful landscapes are largely erosional, dominated by horizontal and vertical features. No wonder Upheaval Dome stands out.

Valley of the Gods shows the horizontal/vertical nature of the Colorado Plateau.

The remarkably round structure center left is Upheaval Dome (Google Earth; annotations added).

"Upheaval Dome" may seem an inappropriate name for a hole. However the rock layers surrounding it are indeed tilted, and though there's no top, geologists agree this is a dome. But what heaved it up is another matter. Wildly different theories have been debated for at least a century.

A decapitated dome with tilted strata encircling highly contorted rock; UGS photo, annotations added.

I would have loved to read the thoughts of the first geologists to peer over the rim! Surely they were surprised. But it appears this dome wasn't described until 1927, by which time it was already known to geologists—as Christmas Canyon Dome.

In the summer of 1926, petroleum geologist Thomas Harrison surveyed the area between the Colorado and Green Rivers, known to be underlain by a thick layer of salt. Elsewhere in the world buried salt created reservoirs for petroleum. Maybe this salt did too.

In his report Harrison explained that many of the domes he examined were gentle folds deserving further exploration. However there was a dramatic exception: "one discovered by Marland [Oil Co.] geologists shows a remarkable and very unusual development. This is the Christmas Canyon Dome." Harrison described a "sharp and highly distorted crest" and a "trough which closely and completely circumvents it" but that was all (1).

How could anyone look at Upheaval Dome and limit themselves to a one sentence description?! Perhaps Harrison didn't visit it himself, relying instead on discussions with Ben Parker of Marland Oil, who supplied a map and diagram.

Ben Parker's diagram of Christmas Canyon Dome; note steepness of deformed strata.

Harrison was not the only geologist working between the Green and Colorado Rivers in 1926. Edwin McKnight of the US Geological Survey was there too—mapping topography, describing and mapping rock units, investigating geologic structures, and assessing potential for manganese, oil and gas, among other things. After finishing in early summer of the next year, he promptly prepared a preliminary report. But the final report was delayed "by the assignment of the writer to other projects." Geology of Area between Green and Colorado Rivers was finally published in 1940, by which time Christmas Canyon Dome had become Upheaval Dome (2).

McKnight devoted five pages to Upheaval Dome, "the most peculiar structural feature in southeast Utah". He described it from the center outward. An interior conical dome, circular at the base, is surrounded by a ringlike syncline (narrow valley) and, beyond that, a circular ridge about a half mile wide. "The complete diameter of the affected area is 3 miles."

From map accompanying McKnight's report; Upheaval Dome is the tightly concentric red contour lines, 100 vertical feet apart (3).

The slopes of the interior dome were steep, generally 40–60º. But they ended prematurely, and the dome's summit was gone. Instead a large hole revealed spectacularly contorted innards. Here, McKnight couldn't hide his excitement:

"The White Rim member does not occur in place but appears as huge up-ended blocks the size of a house in the highly disturbed area of jagged pinnacles at the center of the dome. Surrounding this is the Moenkopi, very much crumpled and dissected by numerous gullies. The Shinarump [now part of the Chinle] forms a jagged fringe to the Moenkopi, its huge tilted triangular blocks sticking up like the teeth of a saw." [names refer to rock layers]

Huge tilted triangular block of the Shinarump sticking up like the tooth of a saw.

Just as amazing, though not so dramatic visually, are the rock layers immediately beyond the outer rim. They're horizontal! Intense deformation had been highly localized.

From McKnight's cross-section, labeled arrows added; note horizontal layers beyond the dome, and question marks inside it.

McKnight attributed the rise of Upheaval Dome to the thick layer of buried salt below, the one that drove Harrison's search for petroleum. It was deposited 300 million years ago in the great Paradox Sea, an inland sea sometimes connected to the ocean, sometimes not. When sea level dropped sufficiently, it was sucked dry by evaporation leaving thick salt deposits. Then the sea returned. There were on the order of 29 such cycles over a period of 15 million years, producing 6000 vertical feet of salt. With burial under younger sediments, it turned to rock.

Extent of the great Paradox Sea; courtesy Jack Share.

Salt is a sedimentary rock but an odd one—plastic and able to flow. It can move underground, accumulate and ooze upward, and deform overlying rock. Given the abundance of salt in the area, McKnight thought salt uplift the likely explanation for Upheaval Dome (4).

"Because of the known occurrence of thick salt under the Upheaval Dome, the writer prefers to consider this feature a salt dome. The rock in the center of the dome is greatly broken, mashed, and squeezed, as if it had been plastically kneaded ... The massive sandstones on the axis of the peripheral syncline also appear to have been deformed plastically and do not show the breaking and shattering that would be expected had they been deformed rapidly and near the surface. ... Every indication points to slow deformation under thick cover ..." (italics added).

Uplift is only part of the story behind today's Upheaval Dome. For millions of years after it rose, younger sediments were deposited over it, eventually becoming a cover of rock something like a mile thick (UGS). Then about six million years ago the Colorado Plateau began to rise. Streams were steepened and invigorated, enabling rapid erosion (NPS). Thousands of vertical feet of rock were removed, along with the summit of Upheaval Dome.

Upheaval Dome, revealed by erosion. Photo by Doc Searls.

The "salt theory" is fascinating, but it has problems. For example no remnants of salt have been found in the area of the dome (UGS). And seismic survey and drill holes have shown Paradox salt to be 1500 ft below the surface, i.e., well below the dome (Fillmore 2011). So the salt theory was modified. Perhaps Upheaval Dome is a salt diapir—created by a blob of salt that rose and was pinched off from its source below. Subsequent erosion removed it along with overlying rock, explaining the lack of salt remnants. But if this really is a salt diapir, it's the weirdest one ever, unlike any other in the world (Ornduff et al. 2006).

Fortunately there's another way to create a decapitated dome with highly contorted rocks and markedly localized deformation. And it can be done in less than a minute instead of 20 million years.

From NPS Upheaval Dome Trail Guide, 1993.

Perhaps c. 170 million years ago a meteorite slammed into this very spot. In the first tenth of a second, it would have greatly compressed the surface, and then sent a shock wave radiating outward, excavating a giant crater. This was followed by collapse of the crater rim and rebound of the compressed core, creating a dome of deformed rock. As in the salt theory, subsequent deposition buried the rebounded dome; then erosion removed the rock cover and top of the dome, exposing the contorted rocks inside. (Today's hole is NOT the impact crater, whose remnants were removed by erosion. But the two are easily confused.)

For years evidence had been accumulating in support of meteorite impact (e.g. Kriens et al. 1999). But there was a problem. No altered rocks singularly diagnostic of meteorite impact had been found. So the salt-meteorite debate raged on.

Then in 2008, Buchner and Kenkman proclaimed that impact origin for the "Sphinx of Geology" (Upheaval Dome) had been confirmed. They examined 120 thin sections of rock from the outer edge of the ring syncline and found shocked quartz, which only forms in meteorite impacts and nuclear explosions! Actually, the "vast majority" of the quartz grains in the rocks did not exhibit shock features. But they found two that did. These tiny "smoking guns" were said to be unequivocal evidence of meteorite impact.

The world of information adapted. Wikipedia declared meteorite impact the accepted theory. The Utah Geologic Survey announced that Utah's Belly Button, once considered an "outie" is now an "innie". My favorite southern Utah geo guides—Ornduff and pals—argued persuasively against salt, noting that "the most recent studies point to the meteorite theory".

As of 2024, the National Park Service wisely remains non-committal.

Yet there's still a problem. In addition to shocked quartz, Upheaval Dome has rock layers that clearly were tilted slowly, on the order of millions of years. So another possibility must be considered—perhaps a meteorite impact caused a salt diapir! (Daly & Kattenhorn 2010; Gessaman et al. 2015).

But I'm stopping here, having dwelt long enough on how Upheaval Dome might have formed. For me, the mystery doesn't diminish its chaotic and awesome beauty. In fact, it enhances it.

What hath God wrought?

Notes

(1) Harrison concluded that at Christmas Canyon Dome "beds have been too highly buckled and faulted" to justify exploration for oil.

(2) Thanks to the Utah Geologic Survey for supplying me with papers by early geologists, and for trying to solve the mystery of "Upheaval Dome" (the name). If you know its source, please Comment below.

(3) McKnight took pains to explain the unusual contour lines of Upheaval Dome: "The general shape of the dome and surrounding syncline is depicted with fair accuracy on plate 3, but because the information on which this part of the map is based was not detailed enough for mathematical representation of such features as the exact structural depth and configuration of the syncline and the exact closure on the central dome, the structure contours within the involved area have been dotted."

(4) As further evidence of salt deformation, McKnight noted that "Upheaval Dome closely approximates the theoretical form for salt domes under certain conditions", citing Nettleton, LL. 1934. Fluid mechanics of salt domes. Am. Assoc. Petr. Geol. Bull. 18: 175-1204.

Sources

The amount of information (and speculation) available for Upheaval Dome is truly overwhelming! These are sources I found useful.

Buchner, E. & Kenkmann, T. (2008) Upheaval Dome, Utah, USA: impact origin confirmed. Geology, 36, 227–230.

Daly, RG, and Kattenhorn, SA. 2010. Deformation styles At Upheaval Dome, Utah imply both meteorite impact and subsequent salt diapirism. 41st Lunar and Planetary Science Conference. PDF

Fillmore, R. 2011. Geological Evolution of the Colorado Plateau of Eastern Utah and Western Colorado. Includes lengthy discussion of competing theories.

Geesaman, PJ, et al. 2015. New evidence for long-term, salt-related deformation at Upheaval Dome, SE Utah. Abstract and slides.

Harrison, TS. 1927. Colorado–Utah Salt Domes. Am. Assoc. Petroleum Geologists 11:111–133.

Kriens, BJ, et al. 1997. Structure and kinematics of a complex impact crater, Upheaval Dome, southeast Utah. USGS.

McKnight, TS. 1940. Geology of area between Green and Colorado rivers, Grand and San Juan Counties, Utah. USGS Bull. 908.  [Upheaval Dome p 124–128]

National Park Service (NPS). Stretching of the Basin and Range and Lifting of the Colorado Plateau. Accessed Feb 2025.

Ornduff, RL, et al. 2006. Geology Underfoot in Southern Utah. Mountain Press. Vignette 28, "At the Mystery's Core", is about Upheaval Dome.

Share, Jack. 2011 (May 29). The Enigma of Upheaval Dome: Diapiric Salt or Ground Zero.

Utah Geologic Survey. Utah's Belly Button, once considered an "outie" is now an "innie". [UD is one of  many wonderful Utah GeoSites offered online, great for planning roadtrips.]