Green River overlook, Island in the Sky District, Canyonlands National Park, southeastern Utah

The stream is still quiet, and we guide 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. These are the words Major John Wesley Powell used to describe what is called Stillwater Canyon along the Green River on July 17, 1869, on his way to the Grand Canyon during his famous journey exploring the canyons of the Colorado River and its tributaries (Powell, 1895). This same region is spectacularly displayedfrom the Green River Overlook in the Island in the Sky District of Canyonlands National Park. The exposed rocks consist of Early Permian- (299 million years ago [Ma]) through Early Jurassic-age (176 Ma) rock layers that were uplifted and subjected to massive erosion. Changes in the color, thickness, and composition ofthe rock layers and erosive work of running water and gravity (i.e., mass wasting) created the magnificent landscape seen at the overlook today. The primitive and remote Maze District of Canyonlands National Park is the area west of the Green River. Prominent features viewed in the Maze District from the Green River Overlook include Ekker Butte, Turks Head, Elaterite Butte, and the Orange Cliffs (figure 2). On a clear day, the 11,000-foot (3350 m), Henry Mountains, which are cored by volcanic remnants (laccoliths) can be seen to the southwest. The Green River Overlook is one of Utah’s most iconic views, often appearing on book covers, scenic calendars, and postcards, and therefore it is fitting as a geosite for its beauty and the exposures of rocks that so much impressed John Wesley Powell over 150 years ago.

Cut, Fill, Repeat: Slot Canyons of Dry Fork, Kane County

The slot canyons of southern Utah have become popular destinations for hikers, climbers, and photographers. For most of these canyons, the geology is simple: sediment carried by flowing water abrades a thick, homogeneous sandstone. As time passes, the rate of down- cutting is rapid compared to the rate of cliff retreat. End of story. The strange abundance and configuration of the slot canyons along Dry Fork Coyote (a tributary of Coyote Gulch and the Escalante River), however, have a convoluted geologic history that is climate-driven and involves canyon cutting, canyon filling, and more canyon cutting.

Rock Canyon near Provo, Utah County: A Geologic Field Laboratory

Rock Canyon near Provo, Utah is an ideal outdoor laboratory. The canyon has been known and explored for many years by scientists and students for its fascinating geology, biology, and botany. It is also a favorite location for rock climbers, hikers, and other outdoor enthusiasts. Facilities near the mouth of the canyon including parking, restrooms, a lecture amphitheater, and a covered pavilion with picnic tables provide an ideal location for visitors. Geology is the focal point of this beautiful canyon with a history that stretches from the Precambrian (about 700 million years ago) to the Wasatch fault and Lake Bonneville, which covered much of western Utah at its peak roughly 18,000 years ago. Excellent exposures of the rocks allow visitors to see features clearly and piece together the history of the canyon. The oldest rocks are glacial deposits of the Mineral Fork Tillite. The tillite is overlain by a thick section of Paleozoic rocks of Cambrian to Permian age, all of which have been deformed into an asymmetric, overturned fold formed during the Sevier orogeny, a roughly 140 to 50 million year old mountain building event. The upper reaches of the canyon were sculpted by glaciers during the Pleistocene and deposits of the Provo and Bonneville levels of Lake Bonneville are found at the mouth of the canyon, now cut by a recent alluvial fan. Also, at the mouth of the canyon are excellent exposures of features associated with the Wasatch fault.

Dead Horse Point, Southeastern Utah

The Dead Horse Point geosite, within the state park by the same name, is located in the heart of the Canyonlands region of Utah between Canyonlands and Arches National Parks. The views are spectacular, sublime, awe-inspiring, and majestic, and hard to surpass anywhere on the Colorado Plateau. The mood of the vistas changes by season and time of day. Here, one of nature’s engineers, in this instance the Colorado River and its tributaries, has carved and exposed strata of Late Pennsylvanian (307 million years ago [Ma]) to Early Jurassic (200 Ma) age within just the past 5 million years (figures 2 and 3).

A Breccia Pipe in the Deseret Limestone, South Flank of the Uinta Mountains, Northern Utah

A breccia pipe is a cylindrical- or irregular-shaped mass of brecciated rock. A breccia consists of broken, angular fragments of rock cemented together by a fine-grained matrix. Hydrothermal breccia pipes form when hydrothermal solutions force their way towards the surface through zones of weakness or fracture zones and naturally break up the rocks in the process, i.e., hydrofracturing; breccia pipes can also form by collapse. Hydrothermal breccia pipes can contain ore deposits and, as will be discussed later, are associated with some large oil and gas accumulations in southeastern Utah.

Landscape Arch, Delicate Arch, and Double Arch in Arches National Park, Southeastern Utah

Arches National Park in southeastern Utah has the greatest concentration of natural rock arches in the world. The park is located in a geologic region called the Paradox fold and fault belt in the northern Paradox Basin and showcases spectacular and classic Colorado Plateau geology with its colorful sedimentary rocks, ancient sand dunes, cliffs, domes, fins, and pinnacles, as well as the arches. The arches in the park and the surrounding region were formed by a unique set of circumstances involving Middle Pennsylvanian (about 308 million years ago [Ma]) to Late Triassic (200 Ma) movement of subsurface salt layers, Middle Pennsylvanian to Late Cretaceous (about 70 Ma) deposition, and Tertiary and Quaternary (23 Ma to the present) folding, faulting, erosion, and salt dissolution. Massive, hard, brittle sandstones jointed by folding, resting on or containing soft layers or partings, and located near fold structures such as salt-cored anticlines undergoing dissolution, and a dry climate, all favor the formation of arches. Rarely do all these phenomena occur in one place, but they do in Arches National Park.The Natural Arch and Bridge Society (NABS) stated, “A natural arch is a rock exposure that has a hole completely through it formed by the natural, selective removal of rock, leaving a relatively intact frame.” They also make it clear that a natural bridge (which is at least partially formed by flowing water) is one type of natural arch (NABS website) (see A Bit of Perspective, below, for more explanation). Using their own criteria, Stevens and McCarrick (1988) catalogued over 2000 natural arches in Arches National Park; most have unique characteristics that could qualify them as geosites. However, the three most famous arches in the park, and perhaps the world, are Landscape Arch, Delicate Arch, and Double Arch, and thus these were selected as the geosites for this paper.

Ricks Spring

Ricks Spring is one of several major karst springs that discharge along the Logan River in the Bear River Range in Cache County, Utah. The spring is located along U.S. Highway 89 in Logan Canyon about 17 miles (27.4 kilometers) northeast of (up-canyon from) the city of Logan, at mile marker 477. It lies within Uinta-Wasatch-Cache National Forest at an elevation of 5880 feet (1792 meters). Situated at the base of a hillside, the spring is one of the largest and most scenic along the Logan River (figure 1). Water from the spring flows out of a large alcove, under Highway 89, and into the Logan River, about 150 feet (45 meters) from the spring. Pullouts on both sides of the highway provide parking for visitors to the spring, and a boardwalk crosses the spring run, which allows access to the rise pool in the alcove. Several signs at the spring provide information about its history and hydrology. Ricks Spring typically flows during the spring, summer, and fall months, but can have periods of no flow during the winter months, particularly during extended periods of cold weather. During these times, the water in the rise pit recedes to a small pool of standing water that can contain fish, which presumably originate from the nearby Logan River. During the last 10 years, cave divers have explored the conduit that feeds the spring for about 2300 feet (700 meters) into the mountainside.

Devils playground, Box Elder County

Why take your kids to the neighborhood playground, when you can visit a playground that inspires their sense of geologic adventure? Devils Playground is not your ordinary community playground, but a wonderland of granitic rock weathered into fantastic forms and weird shapes. Occupying an assortment of Bureau of Land Management, state, and private land in the Bovine Mountains, Devils Playground is a relatively unknown geologic curiosity found in a remote corner of northwestern Utah. Devils Playground is situated in the physiographic region known as the Great Basin province that extends across western Utah, Nevada, and to the Sierra Nevada Mountains in eastern California. The area is composed mostly of granitic rocks of the Emigrant Pass intrusion. A combination of granitic rock, faulting, and weathering under a semiarid climate created favorable conditions for the creation of Devils Playground. Desert plants such as sagebrush,Utah juniper, pinyon pine, Mormon tea, and cheatgrass are common throughout the area.

Independent gilsonite vein, Uintah County

The Uinta Basin of northeastern Utah contains a wide variety of hydrocarbon resources including vast accumulations of crude oil and natural gas deposits, one of the largest oil shale resources in the world, and the largest tar sand deposit in the United States. In addition, unique solid hydrocarbons, including gilsonite, wurtzilite, tabbyite, and ozokerite, have a long and colorful history of exploration and/or production in the region. The most abundant of these, gilsonite, occurs in distinctive swarms of subparallel, northwest-trending veins. The lateral continuity of the veins is impressive, with relatively long, straight ribbons stretching across the hills of the eastern Uinta Basin. The veins are also vertically continuous, extending hundreds to more than 3000 feet (900 m) below the ground, commonly having only small variations in width. The Uinta Basin contains the world’s largest deposit of gilsonite and is the only place in the world where this unique resource is economically produced. Gilsonite is remarkable for its unusual geologic origin, chemical and physical properties, and industrial uses. Industry pioneers are noted for creating innovative uses for their product and for over 100 years have solved mining, processing, transportation, marketing, and other challenges to supply gilsonite to world markets. Accordingly, gilsonite has been studied and described in a large body of research dating back to the 1880s. Most recently, the Utah Geological Survey (UGS) published Special Study 141 (Boden and Tripp, 2012), which presents the latest mapping of gilsonite deposits and a compilation of existing data. To date, over 70 significant veins and vein systems, having a total combined vein length of over 170 miles (270 km), have been mapped by UGS geologists.

The Wind-Swept Nautilus, Enigmatic Clastic Pipes, and Toadstool Landforms: Geologic Features of the Paria Plateau

The Colorado Plateau occupies much of the southwestern United States including portions of Arizona, Colorado, Utah, and New Mexico. This region presents unobstructed views from mesa tops, beautifully colored soils, lone standing buttes, and canyons cut thousands of feet deep. The Colorado Plateau represents a well-preserved window into the Earth’s history. Today, the rocks of the Colorado Plateau lie roughly horizontally, as they were deposited hundreds of millions of years ago. The Plateau’s rise has motivated rivers, in their downhill progress, to carve innumerable canyons. These river canyons allow any nature-lover the opportunity to gaze at 100s of millions of years of geologic history. Within the larger Colorado Plateau, the Paria Plateau straddles the Utah and Arizona borders, and includes the Vermilion Cliff s National Monument, the Paria Canyon-Vermilion Cliffs Wilderness Area, and the southern extent of the Grand Staircase Escalante National Monument (GSENM; pre-2018 boundaries). The Paria Plateau is best known for spectacularly colored, wind-sculpted features such as Coyote Buttes and “The Wave,” where vivid colors accent cross-strata resembling a cresting ocean wave. The Plateau is also recognized for the geologically notable Vermilion Cliff s, Buckskin Gulch slot canyon, White Pocket area, and the Paria River Canyon. Although only two, dual-lane highways circumvent the plateau, several wash-boarded gravel and deeply mud-rutted roads allow access to its interior. From these dirt roads, a few sandy, four-wheel drive paths diminish as they extend and branch into the plateau’s interior. Overall, the Paria Plateau is a relatively quiet and little-visited wilderness.