Powell’s 1869 Journey Down the Green and Colorado Rivers

Major John Wesley Powell’s 1869 Journey Down the Green and Colorado Rivers of Utah

by Thomas C. Chidsey, Jr.

Past these towering monuments, past these mounded billows of orange sandstone, past these oak-set glens, past these fern-decked alcoves, past these mural curves, we glide hour after hour, stopping now and then, as our attention is arrested by some new wonder…

These words by Major John Wesley Powell, August 3, 1869, describe the scene as he and his comrades floated along the Colorado River in what is now southern Utah. Anyone who now travels his same route or visits the various national parks and surrounding regions likewise has their “attention arrested by some new wonder!” Powell is best known for his historic journey down the Colorado River through the depths of the Grand Canyon 150 years ago. However, of that 1,000-mile journey, about 570 miles (roughly 58 percent) were down the Green and Colorado Rivers through Utah. Most of the spectacular areas and landmarks along the way that are so familiar to generations of Utah citizens and visitors were named by Powell and his party.

The purpose of Powell’s 1869 expedition was to survey the geology, geography, and water resource potential for settling the region, and document ethnography and natural history of the canyons of the Green and Colorado Rivers. Though his expedition was “scientific,” Powell was well aware that he was competing with other government surveys for funds, and that adventures such as his river journey drew much public interest and support. The expedition was made possible, in part, by the construction of the Transcontinental Railroad (Union Pacific) through Wyoming, which delivered four modified, round-bottomed Whitehall rowboats that were built in Chicago: Maid of the Cañon, Kitty Clyde’s Sister, No Name, and the Emma Dean named after Powell’s wife and specially rigged for him to command during the trip to accommodate him having one arm.

Powell and his party of nine others departed Green River Station (now the town of Green River, Wyoming) on May 24, 1869, two weeks after the Golden Spike had been laid at Promontory, Utah, completing the Transcontinental Railroad. The boats were laden with supplies to last 10 months and they took several scientific instruments including sextants, chronometers, thermometers, compasses, and barometers (to measure the altitude of the river and surrounding terrain). They would endure numerous hardships along the way including negotiating hundreds of rapids, the loss of two boats with much of their supplies and scientific instruments, surviving near drownings, food spoilage and near starvation, and even outrunning a flash flood. One member of the crew would depart the expedition near Vernal, Utah, having had enough adventure, and three others left near the journey’s end thinking an impending rapid too dangerous—they were never seen again.


Traveling uneventfully down 60 miles on the Green River, most of which is now Flaming Gorge Reservoir, Powell and his party reached the Utah Territory on May 26.

The river is running to the south; the mountains have an easterly and westerly trend directly athwart its course, yet it glides on in a quiet way as if it thought a mountain range no formidable obstruction. It enters the range by a flaring, brilliant red gorge, that may be seen from the north a score of miles away. The great mass of the mountain ridge through which the gorge is cut is composed of bright vermilion rocks; but they are surmounted by broad bands of mottled buff and gray, and these bands come down with a gentle curve to the water’s edge on the nearer slope of the mountain. This is the head of the first of the canyons we are about to explore—an introductory one to a series made by the river through this range. We name it Flaming Gorge [1 on map].

Major John Wesley Powell,
May 26, 1869

The mountain range Powell describes is the east-west-trending Uinta Mountains. The rocks at the entrance to Flaming Gorge that so much impressed Powell are the north-dipping, slope-forming, vermilion-colored Triassic (251 to 200 million years ago [Ma]) Moenkopi and Chinle Formations overlain by the buff-gray Triassic-Jurassic (200 to 183 Ma) Nugget Sandstone and the Jurassic (169 to 155 Ma) Carmel, Entrada, and Stump Formations.


After crossing the Uinta fault, the Green River follows a generally easterly course through Precambrian (800 to 770 Ma) rocks exposed spectacularly in Red Canyon (now popular for river rafting below the Flaming Gorge Dam) and then Browns Park. Eventually (after about 54 miles), the river enters Colorado through the Gates of the Lodore and turns south into a region that is now part of Dinosaur National Monument where Powell lost the No Name, much of their supplies, and scientific instruments in a rapid they appropriately named Disaster Falls. After the river course changes to the west, it reenters Utah.

The Green is greatly increased by the Yampa [River], and we now have a much larger river. All this volume of water, confined, as it is, in a narrow channel and rushing with great velocity, is set eddying and spinning in whirlpools by projecting rocks and short curves, and the waters waltz their way through the canyon, making their own rippling, rushing, roaring music…One, two, three, four miles we go, rearing and plunging with the waves, until we wheel to the right into a beautiful park and land on an island, where we go into camp…e broad, deep river meanders through the park, interrupted by many wooded islands; so I name it Island Park, and decide to call the canyon above, Whirlpool Canyon [2 on map].

Major John Wesley Powell,
June 21 and 22, 1869

The oldest formation exposed in Whirlpool Canyon is the Precambrian (900 Ma) Uinta Mountain Group which is overlain by Cambrian (540 Ma) Lodore Sandstone and Mississippian and Permian (340 to 275 Ma) strata, all relatively resistant to erosion and deeply incised by the river. When Powell exited the canyon and entered the open area he named Island Park, the expedition had crossed the northeast-southwest-trending Island Park fault. This major fault displaces softer, less-resistant Triassic and Jurassic formations on the west side, including the Moenkopi and Chinle Formations exposed in Flaming Gorge, against the Pennsylvanian-Permian (280 to 275 Ma) Weber Sandstone on the east side.


At the lower end of the park, the river turns again to the southeast and cuts into the mountain to its center and then makes a detour to the southwest, splitting the mountain ridge for a distance of six miles nearly to its foot, and then turns out of it to the left. All this we can see where we stand on the summit of Mount Hawkins, and so we name the gorge below, Split Mountain Canyon [3 on map].

Major John Wesley Powell,
June 24, 1869

For the description of Split Mountain Canyon, see the “Glad You Asked” article in this issue.


After passing through Split Mountain, the Green River follows a gentle, south-southwesterly meandering course through the Eocene (55 to 43 Ma) Uinta and Green River Formations in the Uinta Basin. Powell passed many major oil and gas fields that would not be drilled for many years. After about 90 miles the river again downcuts into older rocks which created another major and perilous canyon for the Powell expedition.

After dinner we pass through a region of the wildest desolation. The canyon is very tortuous, the river very rapid, and many lateral canyons enter on either side. These usually have their branches, so that the region is cut into a wilderness of gray and brown cliffs. In several places these lateral canyons are separated from one another only by narrow walls, often hundreds of feet high—so narrow in places that where softer rocks are found below they have crumbled away … Piles of broken rock lie against these walls; crags and tower-shaped peaks are seen everywhere, and away above them, long lines of broken cliffs; and above and beyond the cliffs are pine forests, of which we obtain occasional glimpses as we look up through a vista of rocks. The walls are almost without vegetation; a few dwarf bushes are seen here and there clinging to the rocks, and cedars grow from the crevices—not like the cedars of a land refreshed with rains, great cones bedecked with spray, but ugly clumps, like war clubs beset with spines. We are minded to call this the Canyon of Desolation [4 on map].

Major John Wesley Powell,
July 8, 1869

Desolation Canyon exposes rocks of the Eocene (55 to 45 Ma) Green River and Paleocene-Eocene (about 60 to 55 Ma) Wasatch Formations which, in this area, were deposited as shallow-water muds, shoreline river deltas, and alluvial plains along or near the southern parts of an ancient lake called Lake Uinta. The Green River and Wasatch Formations are major producers of oil and gas in the Uinta Basin.

Again, the large rapids in Desolation Canyon posed major difficulties for Powell and his party. Most of the rapids that they encountered here and along the entire journey formed adjacent to major side canyons when large flash floods deposited boulders in the rivers. These boulders dammed up the rivers (a calm before the storm!) with the rapid created where the water flows over the “dam.”


The Green River continues to follow a southerly course into Gray Canyon, cutting down through the coal-bearing formations of the Cretaceous (84 to 67 Ma) Mesaverde Group until it exits the canyon at the Book Cliffs near the town of Green River, Utah. From there the river continues south, eroding deeper into older strata that create the classic Colorado Plateau canyon country of southern Utah.

…with quiet water, still compelled to row in order to make fair progress. The canyon is yet very tortuous. About six miles below noon camp we go around a great bend to the right, five miles in length, and come back to a point within a quarter of a mile of where we started…There is an exquisite charm in our ride to-day down this beautiful canyon. It gradually grows deeper with every mile of travel; the walls are symmetrically curved and grandly arched, of a beautiful color, and reflected in the quiet waters in many places so as almost to deceive the eye and suggest to the beholder the thought that he is looking into profound depths. We are all in fine spirits and feel very gay, and the badinage of the men is echoed from wall to wall. Now and then we whistle or shout or discharge a pistol, to listen to the reverberations among the cliffs… we name this Labyrinth Canyon
[5 on map].

Major John Wesley Powell,
July 15, 1869

The Green River meanders through Labyrinth Canyon exposing spectacular sandstone cliffs of the Triassic-Jurassic Glen Canyon Group (see cover image). These strata were deposited in great “seas” of wind-blown sand like those of the modern Sahara, separated by a period when the climate changed and westerly flowing, sand-laden braided streams dominated the region.

The Colorado Plateau began rising during the Miocene Epoch (23 Ma). At that time the ancestral Green River and its tributaries flowed through meandering channels in wide valleys on easily eroded rocks such as the now-removed Cretaceous Mancos Shale, still exposed just south of the Book Cliffs. Once these river channels were established, they later became superimposed and entrenched into resistant rocks, such as the sandstones of the Glen Canyon Group, as the landscape changed from one of deposition to one of massive erosion where thousands of feet of sedimentary rocks have been removed.


From Labyrinth Canyon the river continues a similar meandering course, cutting into even older rocks, and enters what is now Canyonlands National Park.

The stream is still quiet, and we glide along through a strange, weird, grand region. The landscape everywhere, away from the river, is of rock—cliffs of rock, tables of rock, plateaus of rock, terraces of rock, crags of rock—ten thousand strangely carved forms; rocks everywhere, and no vegetation, no soil, no sand. In long, gentle curves the river winds about these rocks… rapid running brings us to the junction of the Grand [now the Colorado River] and Green, the foot of Stillwater Canyon, as we have named it [6 on map]. These streams unite in solemn depths, more than 1,200 feet below the general surface of the country.

Major John Wesley Powell,
July 17, 1869

The rocks Powell described from Stillwater Canyon consist of Triassic Moenkopi and Chinle Formations that he first observed in Flaming Gorge, and the Permian (280 to 275 Ma) Cutler Group. The chocolate- to brown-red-colored Moenkopi was deposited in a tidal-flat environment, as attested by its abundance of ripple marks on thin slabs of rocks, and the Chinle, famous for its petrified wood, uranium, and beautiful multicolored mudstone and shale, represents a river floodplain. The Permian Cutler Group consists of the red-brown floodplain deposits of the Organ Rock Formation at river level capped by prominent cliffs of the White Rim Sandstone which represents ancient coastal dunes.

Large uplifts and basins developed in the Colorado Plateau during the Laramide orogeny (mountain-building event) between the latest Cretaceous (about 70 Ma) and the Eocene (about 34 Ma). Canyonlands National Park and the surrounding region is on the northern end of the broad Laramide-age Monument uplift, which is responsible for exposing the impressive stratigraphic section of older rocks carved into by both the Green and Colorado Rivers in southern Utah.


Once past the confluence of the two great rivers, the Colorado River flows in a southwesterly direction descending through one of the wildest series of rapids in Utah until it reaches Lake Powell 23 miles downstream.

We come at once to difficult rapids and falls, that in many places are more abrupt than in any of the canyons through which we have passed, and we decide to name this Cataract Canyon [7 on map].

Major John Wesley Powell,
July 23, 1869

The geology along Cataract Canyon is unique and the Colorado River likely has been a factor in the canyon’s structural development. The river follows a relatively straight course down the axis of a large anticline (upwarp) called the Meander anticline. Open-marine limestone beds of the Pennsylvanian (305 to 300 Ma) Honaker Trail Formation dip to the southeast and northwest, respectively, on each side of the river topped by progressively younger Permian formations. The Honaker Trail is underlain in the subsurface by the older Pennsylvanian Paradox Formation that contains evaporite rocks (gypsum and salt) which were deposited in a restricted marine environment. When under pressure, evaporites can flow like toothpaste being squeezed from a tube and push up the overlying rocks or even reach the surface (Powell recognized one such location and named it Gypsum Canyon, a side canyon to Cataract). The Meander anticline was formed this way and is underlain by a mass of mobilized gypsum and salt. As the Colorado River eroded the overlying section of rocks, the pressure on the evaporites below was reduced allowing them to push up even more. The evaporites withdrew from under the rocks adjacent to the canyon which caused collapse, faulting, and slumping towards the river. This process is still active today and contributes to huge rapids like Satan’s Gut and Little Niagara. This area is known as The Grabens in Canyonlands National Park.


Upon leaving Cataract Canyon, the Colorado River turns westerly and enters the upper reaches of Lake Powell, named, of course, for the famous explorer. After passing the Dirty Devil River, so-called by one of Powell’s men because of its muddy water and foul smell, the rocks become younger in age (Permian, Triassic, and finally Jurassic) to the south.

On the walls, and back many miles into the country, numbers of monument-shaped buttes are observed. So we have a curious ensemble of wonderful features—carved walls, royal arches, glens, alcove gulches, mounds, and monuments. From which of these features shall we select a name? We decide to call it Glen Canyon [8 on map].

Major John Wesley Powell,
August 3, 1869

The features Powell used to name Glen Canyon are most prominently displayed in the Jurassic (190 Ma) Navajo Sandstone, famous for its classic cross-bedding and representing ancient dunes of windblown sand.

Glen Canyon and the canyons in the surrounding region, including those that Powell explored, formed within the past 5 million years by vigorous downcutting of the Colorado River and its tributaries, exposing more than 8,000 feet of bedrock that spans a period of about 300 million years. Powell no doubt would be shocked and amazed to see the reservoir that bears his name. All outcrops at river level and in many of the side canyons that Powell explored are covered by water, in many places hundreds of feet deep. Fortunately, the lake level creates an ideal horizontal datum along which large folds (anticlines and synclines) bring most of those outcrops, ranging in age from Triassic to Jurassic in the heart of Glen Canyon, to places where they can be observed from the comfort of a boat.

The 710-foot-high Glen Canyon Dam, located just south of the Utah border near Page, Arizona, was authorized by Congress in 1956 to provide water storage in the upper Colorado River basin, and construction began that same year. Lake Powell is the second largest reservoir in the United States (Lake Mead in Nevada and Arizona is the largest). The lake is 186 miles long, and with 96 major side canyons, it has more than 1,960 miles of shoreline—more than twice the length of the California coastline. The surface area of Lake Powell is 266 square miles and it is 560 feet deep at the dam. Lake Powell holds up to 27 million acre-feet of water, enough to cover the state of Ohio with one foot of water! The hot arid climate causes an average annual evaporation of 2.6 percent of the lake’s volume. Siltation in the lake averages 37,000 acre-feet per year, brought in principally from the San Juan and Colorado Rivers. That is the equivalent of 6 million dump trucks of silt each year! Even at that rate, it will take 730 years to fill the lake with silt.

Although the most famous part of Major John Wesley Powell’s 1869 expedition was the journey of what Powell called “the Great Unknown” of the Grand Canyon, he first spent most of his time exploring the canyons of the Green and Colorado Rivers in Utah. This expedition represents an amazing feat by Powell and his team at that time. Before Powell left the Utah Territory and entered what is now Arizona, he wrote “…we reach[ed] a point which is historic.” Powell was referring to a point along the Colorado River known as El Vado de los Padres or Crossing of the Fathers, a ford (now under 400 feet of water in Padre Bay in Lake Powell) named for Fathers Dominguez and Escalante who discovered it during their 1776 expedition through the region. For those of us who boat around Lake Powell or Flaming Gorge Reservoir, or raft the Colorado or Green Rivers, we too reach points that are truly historic—first named and described by Powell and his colleagues 150 years ago. Major John Wesley Powell’s expedition was truly a major contribution to science and an incredible adventure that still inspires a spirit of curiosity and sense of wonderment today.

Powell quotes from Canyons of the Colorado, by J.W. Powell, 1895.


Tom Chidsey

is a senior scientist in the Energy & Minerals Program He has worked for the Utah Geological Survey for 30 years primarily conducting petroleum geologic studies. Tom is not only passionate about the geology of Utah, but history as well—especially the Civil War, World War I, and Major John Wesley Powell’s 1869 journey down the Green and Colorado Rivers He has retraced more than 800 miles of Powell’s route by raft and boat In addition, Tom was the senior author of the Utah Geological Association’s 2012 guide to the geology of Lake Powell.

Major John Wesley Powell: 1834–1902

Major John Wesley Powell: 1834–1902

by Mackenzie Cope

Major John Wesley Powell at his desk in Washington, D.C. circa 1890s (Smithsonian Institution Archives, Record Unit 7005, Box 187, Folder: 1; Record Unit 95, Box 18, Folder: 57)

Major John Wesley Powell at his desk in Washington, D.C. circa 1890s (Smithsonian Institution Archives, Record Unit 7005, Box 187, Folder: 1; Record Unit 95, Box 18, Folder: 57)

John Wesley Powell was born on March 24, 1834, in Mount Morris, New York, to Joseph Powell and Mary Dean. He grew up interested in history, literature, botany, zoology, and nature. Powell’s family moved to Ohio in 1838, Wisconsin in 1846, and settled in Illinois in 1851. In 1852, he became a teacher and attended college intermittently at the Illinois Institute, Illinois College, and Oberlin College, but never received a degree.

When the American Civil War started in 1861, Powell enlisted in the Union Army at age 27 as a topographer, cartographer, and military engineer and quickly advanced to a second lieutenant. He took leave on November 28, 1861, and married Emma Dean, the daughter of his mother’s half-brother, but returned to service soon after. On April 6, 1862, at the Battle of Shiloh in Tennessee, Powell was hit with a bullet in his right arm and field surgeons had to amputate it at the elbow. He became a recruiting officer back home in Illinois while recuperating from his injuries, but returned to active duty in 1863 and was promoted to the rank of major.

After the war, Powell taught natural sciences at Illinois Wesleyan University and later at Illinois State Normal University. In 1867, he became the curator of the Illinois Natural History Society Museum and organized a specimen-collecting expedition to Colorado where he climbed Pikes Peak and explored part of the Rocky Mountains.

In 1868 Powell organized the first of his great expeditions in the West to explore the Colorado River and its tributaries, which included his historic passage through the Grand Canyon. Funding for the trip, which started May 24 and ended August 30, 1869, came from the Illinois Natural History Society and Illinois Industrial University, with Powell’s promise of sharing data and specimens for study. Scientific instruments came from the Smithsonian Institution and the Chicago Academy of Science. Rations were provided by the U.S. Army with Congress’s authorization and transportation of the boats was courtesy of the Union Pacific railroad. The purpose of this expedition was to explore previously unmapped areas as well as study the geology and native flora and fauna.

Powell conducted a second expedition on the Colorado River from May 22, 1871, to September 7, 1872. This extended trip focused on collecting evidence and scientific data in the form of photographs, detailed maps, and observations for scientific publications. This expedition was funded by the U.S. Congress to obtain an accurate map of the Colorado River and surrounding areas. Powell wrote about his observations and data in his book, known today as Exploration of the Colorado River and Its Canyons, which is still printed and sold.

During his second Colorado River expedition, Powell employed Jacob Hamblin, a Mormon missionary from southern Utah, to help negotiate the safety of the trip. Hamblin had an excellent relationship with the Native Americans and Powell was able to study the Native American cultures of the West. From his ethnological work on his expeditions, he published Introduction to the Study of Indian Languages, with Words, Phrases, and Sentences to Be Collected in 1877 and Indian Linguistic Families of America, North of Mexico in 1891.

In 1879, Powell became the first director of the U.S. Bureau of Ethnology of the Smithsonian Institution and held the position until his death. Among the many organizations he worked for, one of Powell’s most respected achievements was serving as the second director of the U.S. Geological Survey (USGS) from 1881 to 1894, which he served concurrently with his other positions. He advocated strict water resource conservation based on his exploration of the American West’s river systems and geology. He published Report on the Lands of the Arid Regions of the United States in 1878 where one of his ideas was to draw state boundaries according to watershed areas. While he was the director of the USGS, Powell emphasized mapping and helped influence the call for nationwide 1:24,000-scale topographic maps. He resigned from the USGS in 1894 due to opposition to his water resource conservation efforts from western politicians.

Throughout his time as a geographer, geologist, and ethnologist, Powell helped organize and take part in many organizations other than the USGS. Some notable organizations include the Cosmos Club in Washington, the Anthropological Society of Washington, the Biological Society of Washington, the Geologic Society of Washington, the National Geographic Society, the Geological Society of America, and the American Association for the Advancement of Science.

Major John Wesley Powell died on September 23, 1902, at the age of 68, in his family’s vacation home in Maine and was buried in Arlington National Cemetery with full military honors. Today, Powell is remembered through landforms and natural features named after him (e.g., Mount Powell in the Uinta Mountains and Lake Powell in southern Utah) or by him (e.g., Glen Canyon in southern Utah) across the American West. He is honored for his contributions to geology, geography, ethnology, and the natural sciences as a whole.

A Google Earth© oblique view of Split Mountain and surrounding regions. Browns Park Gates of Lodore Canyon of Lodore Diamond Mountain Plateau Yampa Plateau Yampa River Echo Park Island Park Green River Green River Split Mountain Whirlpool Canyon A Google Earth oblique view

The Curious Case of the Green River in the Uinta Mountains

Glad You Asked: The Curious Case of the Green River in the Uinta Mountains

by Douglas A. Sprinkel

People often ask, Why does the Green River flow toward and through the Uinta Mountains? Or, Why does the Green River cut through the middle of Split Mountain when logically it should have flowed around it? Those questions also puzzled John Wesley Powell during the first-ever scientific exploration of the Green and Colorado Rivers in 1869 (see main article in this issue of Survey Notes).

During their month-long stay in the eastern Uinta Mountains, Powell and his companions explored the Green and Yampa Rivers as well as the side canyons and surrounding peaks. Some of our earliest state-of-the-art scientific measurements and descriptions of the geology were the result of that first expedition. Powell made a second trip down the Green and Colorado Rivers in 1871, as well as several pack trips into the territories of Colorado, Wyoming, and Utah. These overland traverses in 1868, 1869, 1874, and 1875 helped Powell formulate his understanding of the geology of the eastern Uinta Mountains.

During Powell’s first expedition, he noted that the Green River flows from its headwaters in the Wind River Mountains of Wyoming southward across a basin, toward the Uinta Mountains. However, at the foot of this mighty mountain range, instead of being deflected by the obstruction, the river flows directly into the range! This and other examples throughout the Uinta Mountains of where the Green River flows through obvious obstructions instead of around them sparked Powell’s imagination to explain such a peculiarity.

So how did the Green River achieve what seems to be an impossible route? At first Powell thought that the river simply followed established fissures within the range. However, Powell rejected that concept because “…very little examinations show that this explanation is unsatisfactory. The proof is abundant that the river cut its own channel; that the cañons are gorges of corrasion.” Powell concluded that the Green River had to have been running its course before the mountain range formed. Powell recognized that the Uinta Mountains are a large anticlinal fold that formed by uplift. He hypothesized that the uplift had to be slow enough for the Green River to cut into the rising fold without altering the river course. Thus, he surmised that the Green River cut its canyon as the range rose around it, and tributaries that fed into the Green River were agents of erosion that stripped the rock off the axis of the great arch. Had the uplift been rapid, the river would have been deflected to a new course that would take the Green River around the flanks of the Uinta Mountains. Powell coined the term “antecedent valley” for this hypothesis. He also coined the terms “consequent valley” for channels that form as a result of the existing topography and “superimposed valley” for channels that form on low-gradient surfaces over which the channel maintains its course even as the stream cuts down into pre-existing structures. The term “superimposed” has since been shortened to “superposed.” Powell also considered but rejected the notion that the Green River is a superposed stream.

Was Powell right? Work by geologists like Julian Sears in 1924 and Wilmot Bradley in 1936 provided evidence that a network of streams flowed away from the Uinta Mountains into the adjoining basins at the end of Uinta uplift during the Laramide orogeny (mountain-building event) 70 to 34 million years ago including where the Green River now flows toward the range. Sears also provided evidence that later faulting formed Browns Park and argued that the Green River was a superposed stream. However, work by Wallace Hansen from 1965 to 1986 provided the clearest picture of drainage reorganization and capture of the Green River. Stream or river capture (also called stream or river piracy) is the diversion of a stream from its current channel to the channel of the capturing stream, often causing the captured stream to reserve its flow. The lowering of the eastern Uinta Mountains by Neogene (20 million years ago to present) extensional faulting was the agent that caused the change in the eastern Uinta Mountain drainage system and the
ultimate capture of the Green River.

Powell and his companions reached Island Park on June 22, 1869, where they camped on one of the islands on the Green River. While there they explored the area noting topography and geology. They climbed the flank of Split Mountain to view the core of the mountain and the rapids within. Powell noted that the Green River entered the range through its north flank, then turned west down the axis of the fold before it turned south again to exit the mountain through its south flank.

Split Mountain is an anticline formed by uplift along the Island Park reverse fault zone, which is on the north limb of the fold. This faulting and folding are part of the general uplift of the Uinta Mountains. At the time of this deformation, the Mesozoic formations that typically overlie the Paleozoic formations were still present and involved in the folding. During a period of relative tectonic quiescence 34 to 25 million years ago, the flanks of the Uinta Mountains, including Split Mountain and the anticline, were buried by a thick blanket of sediments that became the Oligocene-age Bishop Conglomerate. The Bishop Conglomerate formed a low-gradient slope on which streams meandered. Before the Green River was captured and redirected toward the Uintas, it is thought that the Yampa River meandered across the landscape at nearly the present elevation of the Diamond Mountain and Yampa Plateaus (A). The relatively unobstructed Yampa River incised a canyon into the Bishop Conglomerate generally southwest to the Uinta Basin crossing what would become Echo Park, Whirlpool Canyon, Island Park, and Split Mountain. As downcutting continued, the canyon deepened and eventually cut into the emerging Split Mountain (B). The ancestral Yampa River probably took advantage of Laramide fractures on the flanks and crest of the anticline. The Yampa could have been captured by a stream that flowed down the anticlinal crest. Intriguing, beheaded valleys on nearby Blue Mountain, which could be either an ancestral channel of the Yampa, or of a major tributary, support this theory. Regardless, it seems clear to geologists that Split Mountain is a classic example of a superposed stream (C).

The final chapter in this story is the integration of the Green River into the Colorado River basin. Researchers now think that at Echo Park a tributary of the ancestral Yampa River occupied what is now Canyon of Lodore. In 2005, geologists Joel Pederson and Kevin Hadder argued that the tributary formed as Browns Park filled with sediment around the Gates of Lodore. This accumulation of sediment allowed the tributary to spill over and connect the drainage system in Browns Park with the Yampa River drainage and flow into the Uinta Basin, eventually joining the Colorado River below Green River, Utah. The Green River was now captured and redirected to flow toward the Uinta Mountains, through Flaming Gorge and Red Canyon, and down Browns Park to the spillpoint near the Gates of Lodore, completing the river system we see today (perhaps the river in the Uinta Basin should have been called the Yampa since the Yampa was there first!). So, Powell’s keen observations were amazingly astute, though evidence now shows a much more complicated story than he surmised.

Satellite image of the evaporation ponds at Intrepid Potash Inc.’s mining operation near Moab. Image from Google Earth © 2018 Google.

Glad You Asked: What Are Those Blue Ponds Near Moab?

Glad You Asked: What Are Those Blue Ponds Near Moab?

By Stephanie Carney

If you have ever visited Dead Horse Point State Park, you may have noticed bright blue ponds glistening off to the east. These are not a mirage but are solar evaporation ponds used in the process of mining potash. The mine is currently owned and operated by Intrepid Potash Inc., and the ponds cover about 400 acres of land 20 miles southwest of Moab.

Sylvite from Intrepid's potash mine, Moab, Utah.

Sylvite from Intrepid’s potash mine, Moab, Utah.

Potash, a water-soluble potassium salt, is solution mined from the Paradox Formation more than 3,000 feet below the ground. Water from the Colorado River is injected down through a well into the potash-bearing strata, where it dissolves the salts. The resulting brine is extracted from a different well and pumped into the evaporation ponds. Blue dye is added to the water to enhance evaporation. The dye increases the absorption of sunlight and therefore increases the rate of evaporation. As evaporation progresses, the ponds become shallower and turn shades of light blue while the potash precipitates out of solution and is deposited on the bottom of the pond. The ponds turn a tannish brown color when nearly all the water has evaporated and the potash is ready to be harvested.

Satellite image of the evaporation ponds at Intrepid Potash Inc.’s mining operation near Moab. Image from Google Earth © 2018 Google.

Satellite image of the evaporation ponds at Intrepid Potash Inc.’s mining operation near Moab. Image from Google Earth © 2018 Google.

“Potash” is a general term that refers to a variety of potassium salts, such as potassium chloride (KCl), that are mainly used in fertilizer products, but also in the production of soap, glass, ceramics, and batteries. Historically, the term refers to potassium carbonate (KCO3), which is obtained by combining ash from burned plant material (usually hardwood trees) with water in large iron pots. Through evaporating and leaching of the “pot ash,” a residue of potassium carbonate is left behind that historically was used in the process of making soap or glass and ceramic products as early as A.D. 500. In North America in the 17th and 18th centuries, potash became an important industrial chemical and agricultural commodity. Large asheries were built to process the timber cleared and burned by settlers as they expanded westward across the U.S. By the mid-19th century, however, asheries became obsolete after a large deposit of natural potash was discovered in Germany and the birth of potash mining began. Natural potash deposits occur all over the world, but the largest reserves are in Canada. Other significant deposits are in Russia, Belarus, China, Israel, Jordan, and the U.S.

Schematic diagram of solution mining at Intrepid Potash Inc.’s Moab operation.

Schematic diagram of solution mining at Intrepid Potash Inc.’s Moab operation.

The potash mined near Moab is from the Pennsylvanian-age Paradox Formation, which was deposited between 315 and 310 million years ago in the Paradox Basin. During the Pennsylvanian period, the basin was an embayment to a large ocean and experienced cycles of open-marine conditions with freely circulating ocean water and restricted-marine conditions where access to the open ocean was blocked. During open-marine conditions, layers of shale, siltstone, limestone, and dolomite were deposited. When the basin was closed, the hot and dry climate during this time led to high rates of evaporation, and layers of salt were deposited. The salt is mostly halite (NaCl), but layers of sylvite (KCl) and carnallite (KMgCl3.6H2O) were also deposited.

Geologists have identified at least 29 cycles in the Paradox Formation, each represented by a specific sequence of sedimentary and evaporite rock layers, though only 18 cycles are known to contain potash minerals and only a few of those may have economically viable deposits. Individual salt deposits can be up to 1,000 feet thick in some places in the basin. Under the pressure of overlying strata, salt becomes ductile and because it is less dense than other rocks, it moves upward creating folds and diapirs. The Cane Creek anticline, in which the Intrepid potash mine is located, is a large, broad fold created by salt moving upward and bowing the rock layers above it. The potash mined by Intrepid is from Paradox Formation salt cycles number 5 and 9, which occur near the top of the formation. The salt is about 200 feet thick in cycle 5 and about 150 feet thick in cycle 9. The mined potash zone within each cycle, however, is much thinner, typically less than 10 feet thick.

Paleogeographic map of Utah during the Pennsylvanian period, approximately 308 million years ago, showing the Paradox Basin as an embayment to a western ocean (map modified from Ancient Landscapes of the Colorado Plateau by Ron Blakey and Wayne Ranney).

Though the cyclic deposits of the Paradox Formation were discovered in the 1920s, it was not until the mid-1950s during exploration for oil and natural gas that a potential economic potash resource was discovered within the Cane Creek anticline. By the early 1960s, the Texas Gulf Sulfur Company had built an underground mine and began room-and-pillar mining the potash from cycle number 5. Before operations began in 1964, however, an explosion of methane gas trapped 23 men, 18 of which were killed, during construction of the mine.

Because of hazardous gas pockets, high mine temperatures, and the thin, contorted, and difficult-to-mine potash layer, the operation was converted to solution mining in 1970.

The U.S. Geological Survey estimates that the Paradox Basin contains around 2 billion tons of potash resource, though depth to the resource (more than 5,000 feet in some areas) and complex geology have made exploration for economic deposits challenging. The current market price for potassium chloride, the most commonly produced form of potash, is about $200 per short ton, but price has been quite variable in the last decade. Intrepid’s capacity is about 100,000 short tons per year of potassium chloride, from their Moab operation, which is the only potash mine in the basin. Intrepid’s Moab operation along with two other operations in other parts of Utah (see Survey Notes, v. 44, no. 3, p. 1-3) produced 444,000 short tons of potash in 2017 (which includes both potassium chloride and potassium sulfate), the value of which was approximately $210 million. Utah and New Mexico are the only two states that currently produce potash. Because potassium is an essential nutrient for life and there is no substitute, potash mining in Utah likely has a bright and long future.

Energy News: The Benefits of Oil and Gas Production to the State of Utah and Its Citizens—How Things Work!

Energy News: The Benefits of Oil and Gas Production to the State of Utah and Its Citizens—How Things Work!

By Thomas C. Chidsey, Jr.

Over the past decade, Utah has consistently ranked about 10th and 13th in domestic oil and gas production, respectively, in spite of the price collapses that began in 2014. In 2018, over 36 million barrels of oil and 295 billion cubic feet of gas was produced from more than 11,000 wells in Utah. Revenue to Utah and its citizens from oil and gas production varies depending on market prices, land ownership, and the amount produced. A decrease in prices results in less drilling activity and thus a decrease in production. In addition, as oil and gas fields mature, production naturally decreases along with revenue.

Land Ownership

About two-thirds (67 percent) of the lands in Utah are owned by the federal government including National Parks, National Monuments, National Recreation Areas, National Historical Sites, National Forests, Military Reservations, and the Bureau of Land Management (BLM). Other lands in Utah are owned by Native American tribes, the State (including State Parks, Sovereign Lands [the beds of major waterways and lakes, for example the Green and Colorado Rivers, and Great Salt Lake], and School Trust Lands), and private entities (ranches, farms, etc.). The School and Institutional Trust Lands Administration (SITLA) is an independent state agency that manages 4.5 million acres of Utah lands, of which over 1 million acres are currently leased for oil and gas exploration for the exclusive benefit of Utah’s schools and 11 other beneficiaries. Most of Utah’s oil and gas production comes from BLM and tribal lands in the Uinta and Paradox Basins of eastern and southeastern Utah, respectively.

Oil and Gas Royalties

Oil and gas royalties are the cash value paid by a lessee (usually an oil company) to a lessor (the landowner or whoever has acquired possession of the royalty rights) based on a percentage of gross production from the property, free and clear of all costs. Currently, the federal government charges a royalty of 12.5 to 19.6 percent for oil and 9.2 to 12.5 percent for gas extracted from public lands (based on the composition, quality, etc. of the produced crude oil and gas); some royalty agreements with other landowners may be as high as 25 percent. After an oil company discovers oil or gas on federal (or state or private) lands, subsequent wells are drilled to develop and produce the resource. Once production starts, royalties begin to be paid to the landowner(s). For example, if a new well produces 100 barrels of oil per day, and the current market price is $50 per barrel that particular month, then the cash flow would be 100 x $50 or $5,000 per day. The landowner (such as the BLM), who requires a 12.5 percent royalty payment on that production, would receive $625 per day ($5,000 x 0.125).

A question often asked: “Does Utah and its citizens get anything out of oil and gas production on federal lands?” The answer is an emphatic yes! Forty-two to forty-five percent of the royalty payment from oil and gas production (as well as coal, industrial minerals, gilsonite, geothermal, etc.) on federal lands comprise what are called Mineral Lease disbursements and are divided up among several state agencies and counties. For example, the Utah Department of Transportation receives 40 percent of the royalty, a number of counties split 32 percent, and the rest goes to other state entities including the

Utah Geological Survey (UGS). In the example discussed above, Utah would receive $262.50 (42 percent) per day from that one hypothetical well. As total oil and gas production and prices fluctuate, so does the royalty revenue to Utah, ranging from as much as $155 million when oil was over $112 per barrel in 2011 to $64 million when oil dropped to a low of $29 per barrel in 2016. The UGS receives 2.25 percent of the state’s part of this payment, which amounts to one-fifth (20 percent) of the UGS’s annual budget and thus is a critical source of funding that is often difficult to predict. Utah schools received about $28.7 million from oil and gas activities on SITLA lands for the 2018 fiscal year. Like many states, Utah also charges a severance tax (3 to 5 percent; $9 million in 2017) and a conservation fee (0.2 percent; $3.3 million in 2017) based on the value of the oil and gas produced and saved, sold, or transported from the field where it is produced. Finally, Utah charges property taxes on oil and gas facilities; this amounted to $47 million in 2017.

Tax collections on oil and gas production and activities in Utah, and total Mineral Lease disbursements, 2000-2017. Data from Utah State Tax Commission.

Tax collections on oil and gas production and activities in Utah, and total Mineral Lease disbursements, 2000-2017. Data from Utah State Tax Commission.

Some may remember the old 1960s TV comedy The Beverly Hillbillies. Royalty payments turned the poor mountaineer, Jed Clampett, into a millionaire when “black gold” was discovered on his land! In reality, royalty payments to private landowners can be very large or very small and especially complicated. The mineral rights under a ranch or farm, for example, may be divided up (and not always equally) among multiple family members or heirs several generations removed from the property; all are entitled to monthly royalty checks. Wells may produce for 30 years or longer. In addition, many old oil wells are often classified as stripper wells, producing 15 barrels or less per day. Yet royalty payments will continue to be paid to those owners as long as the wells produce. Ten barrels per day x $50 per barrel x 12.5 percent royalty = $62.50 per day. Divide that up among perhaps dozens of people entitled to a share of the royalty and few will be moving to Beverly Hills. Throw in the variations in oil and gas prices as well as changes in production, and oil companies often have to employ large numbers of accountants to handle the monthly royalty payments from hundreds of wells.

Leasing and Subsurface Mineral Rights

Before an oil company drills a well, it must first lease the land from the owner of the subsurface mineral rights. Leasing is usually done after extensive geologic, geophysical, and economic evaluations of an area—subsurface mapping, acquiring seismic data, analyzing cores and well logs, determining the hydrocarbon source and reservoir rocks, estimating dry hole risks and resource potential, and the costs associated with its development (exploration programs, drilling, production wells, and infrastructure such as pipelines). Acquired leases owned by the federal and state government are often obtained through a bidding process. The price per acre varies from less than $10 to $1,000s depending on whether or not the land is within a relatively inactive area, a “hot” new exploration play, or if oil and gas prices are high or low; these monies are also a source of revenue for the federal and state governments. The company may hold on to the lease anywhere from three to ten years after which it goes back to the landowner and can be offered again to interested companies. If production is achieved, the company retains the lease as long as their wells produce (referred to as a lease “held by production,” i.e., HBP). Companies usually try to acquire large blocks of leased acreage to cover their drilling prospects although some pick up small leases just to be “part of the action.” Finally, companies sometimes reduce their risk by forming units or “farming out” a share of their leases and drilling costs with other companies while retaining an interest in any production that may occur.

Covenant oil field, east of Richfield, Sevier County, Utah. The subsurface mineral rights in the field are owned by the BLM, SITLA, and a private entity.

Covenant oil field, east of Richfield, Sevier County, Utah. The subsurface mineral rights in the field are owned by the BLM, SITLA, and a private entity.

Private landowners lease the mineral right under their lands differently than the federal and state governments. Typically, landowners are approached by the oil company or its hired representative, called a landman, who may make a monetary offer, called a “Bonus,” to lease the mineral rights. The price per acre and duration of the lease are usually similar to those owned by the state and federal government; however, small leases may receive smaller offers because companies usually try to tie up larger lease blocks of acreage. As is most often the case, oil and gas are not found under a property, and the only money that the landowner receives will be that from leasing the mineral rights. If oil or gas is discovered under a lease, even a small one, the mineral owner is still entitled to their proportional share (royalty) of the estimated resource being “drained” under the land no matter if a well is actually on the surface of the property or not. Finally, some landowners may not be aware of what mineral rights they own or do not own. They may own all or a portion of the subsurface mineral rights, or if they only own the surface rights, then they get nothing from leasing or production. This situation may occur if previous landowners sold the surface property (a farm or ranch, for example) but retained the subsurface mineral rights, or sold a percentage of the rights to a third party—all independently of how many times the surface ownership changes hands over the years. For example, a farmer may own a 640-acre section (1 square mile) of land but they own the mineral rights to only 320 acres at 100 percent and 40 acres under another part at 50 percent with all remaining mineral rights owned by someone else. However, the surface landowner still has rights even if they do not own the subsurface mineral rights, especially if the oil company conducts exploration or development activities on their land, such as shooting seismic lines, drilling, or building pipelines. The landowner can negotiate reasonable “damage” fees for these activities. For instance, when shooting a seismic line, shallow-depth shot holes may be drilled in an area of interest. Explosive charges are set off in shot holes that create seismic waves, which bounce off the subsurface layers of rock to give a better picture of the geologic structure below. The landowner may receive $300 to $500 in damage fees per hole.

If a landowner is unsure of the mineral rights, the local county clerk’s office can usually help. When contacted by a landman representing an oil company about leasing the mineral rights, a landowner should consider hiring an attorney who specializes in oil and gas leasing. In addition, numerous websites are available with helpful information, advice, and negotiating guidance on leasing. Landowners may also want to know about the geology of their land especially pertaining to oil and gas. Although the UGS cannot specifically evaluate individual properties (hired geologic consultants can, however), we can answer general questions and recommend our numerous publications on oil and gas resources, plays, etc. (see Public Information Series 71, “Utah Oil and Gas,” and Bulletin 137, “Major Oil Plays in Utah and Vicinity,” for example) that are available for free from our website.

Oil and Gas Revenue—The Bottom Line

Revenue from oil and gas production and leasing can be a double-edged sword to Utah and its citizens. When prices are high, the state has more funds for education, roads, and other services. At the same time, high oil prices affect the gas pump. When prices are low, the revenue and its benefits to the state consequentially fall but it becomes cheaper to fill up our vehicles. Ultimately, however, the fact that Utah is rich in oil and gas resources is of great benefit to the state and its citizens, now and well into the future.

Utah Mining Districts at Your Fingertips

Utah Mining Districts at Your Fingertips

By Ken Krahulec

New Utah Geological Survey Products

The Utah Geological Survey (UGS) has produced two new up-to-date, web-available products on the mining districts of Utah. The first is an interactive web page that allows you to explore Utah’s 185 mining districts and learn about the metallic resources of each district, what metals were produced, when the district produced, and the estimated total production value of each district based on recent average metal prices. A particularly useful component to this interactive map is a one-page summary of each district that includes information on history, metals produced, production significance, most important mines, recognized ore deposit types, and geological setting. The summaries also provide a few key references to get the interested reader started on researching more detailed information about the district’s geology and ore deposits. The U.S. Bureau of Land Management helped fund the development of this web page.

The second new product is UGS Open-File Report 695, which has all 185 one-page mining district summaries along with introductory information and an overview of the importance of Utah’s metal production. A 1:1,000,000-scale map of Utah displays all the mining districts and represents the first update to the Utah mining district map since 1983. On the map, each district is color-coded to the total district production value, ranging from zero to greater than $1 billion, and labeled with the district name and primary mineral commodities produced. Appendices list the 38 ore deposit types recognized in the state, chemical formulas of over 200 minerals found in Utah, and abbreviations for the chemical elements used in the text.

Utah Mining Districts Map Image, versioned from UGS publication OFR-695.

Utah Mining Districts Map Image, versioned from UGS publication OFR-695.

The Utah mining districts report includes some interesting findings and statistical information:

  • Utah is the third largest metal producing state in the U.S., behind Arizona and Nevada, in terms of total historical production.
  • For the major base and precious metals, Utah ranks second in the U.S. in the historical production of copper and silver, third in lead, fifth in gold, and ninth in zinc.
  • Historically, Utah is the largest beryllium and magnesium producing state in the U.S., as well as second largest vanadium, third largest molybdenum and uranium, and fourth largest iron producer.
  • Utah’s total historical metal production value, at recent estimated metal prices, is approximately $217 billion.
  • Utah’s most valuable metals in decreasing order of importance are copper, gold, molybdenum, silver, lead, iron, zinc, uranium, beryllium, vanadium, manganese, and tungsten.

Utah Mining Summary

The Bingham mining district in the Oquirrh Mountains of southwestern Salt Lake County is, by far, Utah’s most significant mining district. The Bingham Canyon open-pit mine is recognized as the first open-pit porphyry copper mine in the world, and porphyry copper mines are currently the world’s most important copper producers. Bingham is also the most productive mining district in the U.S. The district has sustained production for over 150 years, and Bingham’s total historical production value is approximately $174 billion and accounts for about 80 percent of Utah’s total historical production value.

The other most productive Utah districts that have over $1 billion of metal production at current metal prices include Park City (2), Main Tintic (3), Iron Springs (4), East Tintic (5), Mercur (6), Spor Mountain (7), and Lisbon Valley (8). Rounding out the top 10 but with less than $1 billion in production value are the San Francisco (9) and Ophir (10) districts.

Currently, the Bingham, Spor Mountain, Lisbon Valley, and Rocky districts all have mines in production. In addition, districts having significant ore reserves or subeconomic resources include the Bingham, Southwest Tintic, Pine Grove, Spor Mountain, Stockton, Iron Springs, Goldstrike, Tecoma, Gold Springs, Fish Springs, East Tintic, Rocky, Lisbon Valley, La Sal, and South Henry Mountain districts. Furthermore, Bingham, Goldstrike, Gold Springs, Rocky, San Francisco, Fish Springs, Southwest Tintic, and Gold Hill all have ongoing mineral exploration programs.

Another significant fact about Utah mining is that the Spor Mountain district in Juab County currently accounts for about 70 percent of the world’s beryllium production, as it has for the past three or four decades. This fact is particularly notable because beryllium is on the U.S. Department of the Interior’s list of 35 mineral commodities (released in May 2018) deemed critical to the U.S.

Other metals found in Utah on the Interior’s critical minerals list include rhenium, platinum, palladium, uranium, and vanadium. Bingham is the U.S.’s second largest producer of rhenium and also produces minor amounts of platinum and palladium. Utah has historically been an important producer of uranium and vanadium from sandstone-hosted deposits on the Colorado Plateau in southeastern Utah; however, these operations are currently on standby due to low prices. Recent increases in vanadium prices due to rapidly rising demand may change this situation.

As this summary suggests, Utah’s metallic deposits and mining history are significant. Given the importance of metals in our modern society and the reserves and resources available in the state, metallic mining should continue to be an important contributor to the Utah economy, potentially including future opportunities for rural Utah communities. Our hope is that the new interactive web page and open-file report will prove useful as up-to-date, accessible, and user-friendly introductions and guides to metallic ore deposits of Utah for public, industry, and government users.

Drones for Good: Utah Geologists Take to the Skies

Drones for Good: Utah Geologists Take to the Skies

By Christian L. Hardwick


n increasingly used technology tool in many job and research fields is the small unmanned aerial system (sUAS). A sUAS includes the aircraft (drone), the pilot on the ground, and the electronics system (radio, laptop, etc.) that connects them. A sUAS can optimize data collection workflows, lower costs, and reduce risk to staff in hazardous areas. The Utah Geological Survey (UGS) has added a quadcopter sUAS to its tool box to assist geoscientists with fieldwork. This addition is part of the new Department of Natural Resources (DNR) sUAS program which regulates and manages the operation of this modern-age tool among its divisions.

HENRY, the UGS sUAS quadcopter. Specifications and features of HENRY include a 20-megapixel camera, 20-minute average flight time per battery in planned missions, 5-direction obstacle avoidance, maximum speed of 45 MPH, and a maximum range of 7 km (4.2 miles).

A sUAS can be used for many things including live video streaming during reconnaissance, search and rescue operations, and capturing images used in aerial mapping projects. The rapid data acquisition that a sUAS provides allows us to more easily survey large areas and to carry out repeat measurements where long-term monitoring is needed. The collection of high-resolution photographs allows us to create detailed orthomosaic maps (several images stitched together) that can aid in the identification of features that may be undiscovered by crews on the ground or unresolved by high-altitude surveys. When photographs are acquired appropriately during the survey, they can be used to create three-dimensional (3D) models of the study area, allowing us to better understand both geologic and man-made structures as well as the geometry of the land. Thermal imaging sensors can also be used with sUAS to help locate thermal anomalies in potential geothermal areas, locate vegetation lineaments that could indicate subsurface features such as faults, and identify hidden water features in hydrogeologic studies.

The UGS has used sUAS in several projects over the past year. Near Lakeside, Utah, high-resolution orthomosaic maps were created and are being used for detailed mapping of lacustrine facies (rocks formed in a lake setting) along the west shore of Great Salt Lake, an area with abundant microbialites (remnants of microbial communities) as well as large-scale travertine and tufa mounds.

Waste Dump landslide aerial survey orthomosaic and 3D terrain model. Survey details include 25 minutes of flight time, 481 photos acquired, and 2 hours of computer processing.

Waste Dump landslide aerial survey orthomosaic and 3D terrain model. Survey details include 25 minutes of flight time, 481 photos acquired, and 2 hours of computer processing.

In Mona, Utah, a high-resolution orthomosaic map in conjunction with a 3D model was used to generate a bathymetry map of Mona Reservoir to investigate relationships between the water level and amount of water in the reservoir. The active Waste Dump landslide along Utah Highway 167 was surveyed to create a 3D model which will assist in the long-term monitoring of the landslide as well as help characterize landslide movement.

Each of these examples presented logistical challenges whether it was the sheer size of the study area, poor access/ground conditions, hazardous environments for staff, or perhaps all the above. The sUAS has become an especially vital tool for geologic hazard analysis. Flights over active landslides enable better mapping and provide safer conditions for geologists studying the event. With the sUAS rapid deployment and processing, the system can provide a timeline of change for landslides as they grow and evolve, providing crucial data for those making public safety decisions. Additional mapping of other hazards, such as fault lines, rockfalls, fissures, and flooding can also benefit from sUAS applications.

The new sUAS is helping the UGS expand its field-data acquisition capabilities. Traditional field-mapping methods are improved by increasing field efficiency, staff safety, and expanding coverage to areas that may have been left out previously due to access, budget and/or time constraints.

Willow Creek No. 1 field site (view to the east) with wireline coring rig in Willow Creek Canyon.

New Core, New Insights into Ancient Lake Uinta Evolution and Uinta Basin Energy Resources

New Core, New Insights into Ancient Lake Uinta Evolution and Uinta Basin Energy Resources

By Ryan Gall

Utah geologists are lucky to have outstanding outcrop exposures in every corner of the state. Our understanding of ancient Utah is built upon these outcrops and geologists from around the globe frequently travel here to study these irreplaceable sources of geologic information. However, outcrops lose some geologic information due to surface weathering that obscures sedimentary features and alters rock chemistry. Fine-grained rocks like claystone are especially prone to poor surface exposure as they break-down quickly and become rooting grounds for modern plants. In contrast, borehole core provides a rare glimpse of strata untouched by surface processes. Cores allow geologists to clearly see sedimentary features like ancient insect burrows and wave ripples in fine-grained rocks that help interpret ancient environments. In addition, cores provide an opportunity to collect geochemical data that can be used to reconstruct paleoenvironments and to characterize petroleum systems.

Willow Creek No. 1 field site (view to the east) with wireline coring rig in Willow Creek Canyon.

Willow Creek No. 1 field site (view to the east) with wireline coring rig in Willow Creek Canyon.

The Eocene-age Green River Formation in the Uinta Basin of northeastern Utah particularly benefits from core study. The Green River Formation was deposited about 55 to 43 million years ago in ancient Lake Uinta, which had similar characteristics to the modern Great Salt Lake (see Survey Notes, v. 46, no. 1, p. 1–3). With abundant fine-grained, organic-rich rocks deposited in the lake, the Green River Formation has gained global attention for its hydrocarbon resources and its paleoclimatic records from the Early Eocene Climatic Optimum (EECO), a period of elevated concentrations of atmospheric greenhouse gases (e.g., carbon dioxide) and extreme global temperatures. In the quest to understand the Eocene environment and better characterize our energy resources, the Utah Geological Survey (UGS) recently partnered with the U.S. Geological Survey (USGS) to drill a new 240-foot-long core from the Uinta Basin—Willow Creek No. 1.

The Willow Creek No. 1 core targets the Uteland Butte member and overlying Colton Tongue–Castle Peak interval of the lowermost Green River Formation. The Uteland Butte is a rising horizontal-well target that has produced over 15 million barrels of oil and over 21 billion cubic feet of natural gas (2010 to present, just from horizontal wells) from a >100-foot-thick interval of interbedded porous dolostone and limestone in the western Uinta Basin (see Survey Notes, v. 50, no. 2, p. 1–3). The Uteland Butte rocks represent the first widespread transgression (expansion) of ancient Lake Uinta. The overlying deposits represent a period of Lake Uinta regression (contraction) dominated by expansive river channels and soil development around the perimeter of the basin (Colton Tongue) and deposition of siliciclastic sediment (e.g., sand) in the relatively small Lake Uinta (Castle Peak). Since 2015, the Castle Peak interval has also been targeted with horizontal wells (28 at time of writing) and numerous vertical/directional wells.

The southwestern Uinta Basin provides a unique opportunity to study the Uteland Butte and Colton Tongue intervals in outcrop, but several details are missed due to heavy weathering and erosion. To obtain fresh rock material, a coring location was selected one mile from where the outcrop of the target interval dips into the subsurface. The site is in Willow Creek Canyon, 18 miles north of Price on a section of land owned by the Utah School and Institutional Trust Lands Administration (SITLA). This dual outcrop-core study will allow us to fully characterize the broad lateral variation of individual beds visible at the ground surface and use the core to collect geochemical data and make detailed observations. These important tasks will help us understand ancient lake-level fluctuations and aid in predicting future oil and gas development potential.

Oblique view of Willow Creek Canyon study area (view north) with overlain stratigraphy, measured section location, and coring location. Satellite images from Google Earth (Landsat/Copernicus 2018; accessed Jan 2019).

Oblique view of Willow Creek Canyon study area (view north) with overlain stratigraphy, measured section location, and coring location. Satellite images from Google Earth (Landsat/Copernicus 2018; accessed Jan 2019).

The core was drilled in mid-August 2018 by a crew from the USGS drilling program. It took only two days to prepare the site and drill 240 feet of core using a wireline coring rig with a special hollow drill bit and a 10-foot core barrel. Upon arrival at the surface, each 10-foot-long core interval was marked with the depth and “up direction” before being packaged for transport to the Utah Core Research Center (UCRC). Once at the UCRC, the core was cut in half―one side will remain in Utah while the other half will be housed at the USGS core facility in Lakewood, Colorado. UGS geologists are currently describing the core inch-by-inch, noting the lithology, sedimentary structures, fossils, and other characteristics. They will also create thin-section slides of selected zones for microscopic analysis and acquire elemental and mineralogical data. Colleagues at the USGS will collect additional mineralogical data and assess thermal properties of the organic matter.

Core-box photo displaying depth-marked and slabbed sandstone with tar accumulation (left, 126.6–132.0 ft) and shallow lake deposits with freshwater bivalves (clams) (right, 132.0–136.0 ft) from the Colton Tongue–Castle Peak interval. 

Core-box photo displaying depth-marked and slabbed sandstone with tar accumulation (left, 126.6–132.0 ft) and shallow lake deposits with freshwater bivalves (clams) (right, 132.0–136.0 ft) from the Colton Tongue–Castle Peak interval.

In addition to studying the new core, UGS geologists measured and described a 360-foot-thick stratigraphic section of the Uteland Butte member and Colton Tongue–Castle Peak interval in Willow Creek Canyon in October 2018. The geologists collected an additional 90 samples from quality outcrop exposures to aid geochemical characterization. Outcrop gamma-ray measurements were also taken every two feet along the measured section. These measurements tell us how the natural radioactivity of the rock varies by layer and is used to tie the outcrop to the gamma-ray log measured in the borehole.

Early observations from core and outcrop show surprising variation in depositional environments over the relatively small study interval. A clear look at the fine-grained rocks, coupled with geochemical analyses, shows that numerable rapid transgressive-regressive lake cycles are the dominant feature of the Uteland Butte and Colton Tongue intervals. These rapid cycles indicate a dynamic hydrologic regime that was incredibly responsive to environmental change and also created the conditions necessary to form dolomite, which acts as a major reservoir for oil and gas deeper in the basin.

Once detailed datasets from the core and outcrop are compiled, UGS geologists can look at basin-scale variation of the lower Green River Formation. This work begins with correlating the wireline logs (gamma, resistivity, porosity, density) collected from Willow Creek No. 1 to the oil and gas well logs and cores (also stored at the UCRC) from the central basin. The correlation will help determine the lateral extent of important strata and how transgressive-regressive cycles are expressed differently near the ancient shore and in the deeper basin. With ongoing collaboration with the USGS, the UGS will also assess the variation of organic maturity to help better understand oil and gas development potential.

This timely core-outcrop study is helping geologists understand some of Utah’s most important petroleum resources and the ancient processes that created them.

This timely core-outcrop study is helping geologists understand some of Utah’s most important petroleum resources and the ancient processes that created them. Given the high-quality data acquired from core and a plethora of outcrop exposures, the UGS has great interest in conducting similar studies of additional Uinta Basin strata to gain a deeper understanding of the evolution of lake basins and their resources.


Ryan Gall

Petroleum Geologist
Ryan Gall joined the Energy and Minerals Program at the Utah Geological Survey in September 2018. With prior experience in sedimentary-hosted mineral exploration and oil and gas production across the western USA, Ryan now primarily focuses on understanding economically important resources in Utah through detailed study of ancient depositional environments.