106 RANGELANDS 14(2), April 1992 Physiographic Provinces and Surface Geology of Utah Roger E. Banner The physicalfeatures of Utah provide some ofthe most most half of the state falls within the Colorado Plateau beautifulscenery anywhere. Utah is a land of stark con- Province, which is divided into three primary sections in trast with high mountains, plateaus, ridges, uplands, Utah: the Uinta Basin, Canyonlands, and High Plateaus. plains, basins, and canyons. Elevations rangefrom a low Several subsections are recognized within these three of 2,350 ft above sea level along the Beaver Dam Moun- divisions. tains in extreme southwestern Utah to 13,528 ft in the Uinta Mountains (Murphy 1981). Murphy (1989b) pre- sents an informative discussion of these features, from which I have drawn much of the content of this paper. Table 1 is a reference to geologic eras, periods, and Table 1. Eras,periods, and epochsthrough geologic time(adapted from Stokes 1986). Millions of Millions of Years Ago Years Duration Geologic Time Begin End Cenozoic Era 66 —— 66 QuartenaryPeriod 2 —— 2 HoloceneEpoch .011 —— .011 PleistoceneEpoch 2 .011 1.989 Tertiary Period 66 2 64 Pliocene Epoch 5 2 3 Miocene Epoch 24 5 19 Oligocene Epoch 37 24 13 Eocene Epoch 58 37 21 Paleocene 66 58 8 Epoch Wah Wah Mountains across Pine Great MesozoicEra 245 66 179 Valley, Basin Section of the Basin and Province, Beaver Utah. CretaceousPeriod 144 66 78 Range County, Jurasic Period 208 144 64 Basin and Range Province-The Great Basin Section Triassic Period 245 208 37 The Great Basin is a region of north-south aligned PaleozoicEra 570 245 325 mountainranges separated by wide, sediment-filled val- PermianPeriod 286 245 41 with internal The mountain Period 320 286 34 leys mostly drainage. ranges Pennsylvanian were formed and were later modified ero- MississippianPeriod 360 320 40 by faulting by DevonianPeriod 408 360 48 sion. Paleozoic Era limestones, dolomites, shales, and Silurian Period 438 408 30 sandstones are the dominantoutcrops along the normal OrdovicianPeriod 505 438 67 fault escarpments (Moyle1981). The valleys are filled with CambrianPeriod 570 505 65 recent sediments from the Cenozoic Era (Ash 1981). PrecambrianTime 4,600 570 4,000 Largealluvial fans have formedat canyonmouths and in some areas the mountain ranges have eroded to the epochs providing some additional perspective on time extent that they are all but buried by deposits of fan that may be helpful in the discussions that follow. material. Four of the in major physiographic provinces North The Pine Valley and Bull Valley Mountains of south- America extend into the wide of Utah, providing variety western Utahare east-west mountainranges thatserve as topography.The Great Basin Section of the Basin and a divide between the Great Basin and the Colorado Pla- Province western Range encompasses Utah and the teau. Extreme southwestern Utah is part of the Colorado Snake River-Columbia Plateau Province dips into a small River of drainage system, not part of the interior drainage area extreme northwestern Utah. The Wasatch Range system of the Great Basin. The terrain of the area is not and the Uinta Mountains, in northern and northeastern different than Great Basin terrain and is are greatly usually Utah, recognized subsectionsof the Middle Rocky mapped as part of the Great Basin. Mountain Section of the Rocky Mountain Province. Al- The Great Salt Lake is a remnant of Lake Bonneville, the Theauthor is Assistant Professorand ExtensionSpecialist, RangeScience largest Quartenary (Cenozoic Era, Quartenary Period, Department, Utah State University, Logan,Utah 84322-5230. RANGELANDS 14(2), April1992 Pleistocene Epoch) lake in western North America. Lake Fault. The eastern flank rises much moregently. Like the Bonneville coveredabout 20,000 square miles and was Uinta Mountains,the Wasatch Range has a core of very more than 1,000ft deep in the area of the presentGreat old (Precambrian Era) quartzites, gneisses, and schists Salt Lake. The Lake Bonnevilleshorelines apparent today overlain by old (Mesozoic Era) sandstones, shales, mud- are a result of at least10 major risesand falls of lake level stones, and limestones (Moyle 1981). Locally, more over the last 100,000 years (Hintze 1975). The other ter- recent (CenozoicEra) conglomerates and shales, inter- minal lake of the Great Basin in Utah, and also a former spersed with volcanictuffs and breccias, form the surface part of Lake Bonneville, is Sevier Lake. Now it is a playa layers of strata (Moyle 1981). which is dry most of the time. It is located in Millard Colorado Plateau Province County, iii west central Utah (Murphy 1989a). Uinta Basin. The Uinta Basin Section of the Colorado Rocky Mountain Province-Middle RockyMountain Section Plateau Province is a synclinal as well as topographic Ulnta Mountains. The Uinta Mountains are an east- basin with an east-west axis running nearthe south flank west mountainrange about 150 miles long and 30 miles of the Uinta Mountains. The highestelevations are around wide. They were formed by anticlinal uplifting with sedi- 9,000 ft at the southern boundary along the top of the mentary units outcropping on all sides and dipping out- Roan Cliffs and the lowest elevations at the basin floor ward. The core of these mountains is very old (Precam- nearVernal are about 5,000 ft. The basincontains 20,000 brian Era) quartzite and the outcrops on the flanks are to 25,000 ft of marineand continentallimestones, shales, ancient(Paleozoic and Mesozoic Eras) Iimestones, shales, and sandstones of old (Paleozoic Era) to recent (Cenoz- and sandstones (Hintze1975, Moyle1981, Murphy198gb). oic Era) age (Moyle 1981). The Green River shales of The Uinta Mountainswere extensively glaciatedin recent recent (CenozoicEra) origin contain vast depositsof oil (Pleistocene Epoch, Quartenary Period, Cenozoic Era) shale and other hydrocarbons. Although the basin is timesand glacial features dominatethe landscape. Glaci- ation created many examples of horns, aretes, cirques, and glacial troughs. Subsequent depositionof moraine by ice and glacial-melt water has created many small high-mountainlakes across the region. View to the north down Willow Creek in me oo - ..._, Basin Section of the Colorado Plateau Province, Grand County, Utah. gently rolling for the most part, there are areas like the Book and Roan Cliffs that have eroded and been cut by View of Wasatch Mountains from a point in the BearRiver Range deep ravines and spectacular canyons. nearHardware Ranch, Middle Rocky Mountain Sectionof the Rocky Canyonlands. The Canyonlands Section of the Colo- Mountain Cache Utah. Province, County, rado Plateau Provinceencompasses thesoutheast quar- Wasatch and Bear River Ranges. The Wasatch and ter of the state. It is dominated by essentiallyhorizontally BearRiver Ranges are similar exceptin extent. The Bear lying old (Paleozoic and MesozoicEra) to recent (Ceno- River Range is a relativelysmall mountainrange of similar zoic Era) sandstones and shales with minor amountsof stratigraphy to the Wasatch Range, located between limestone (Moyle 1981). Recent (CenozoicEra) igneous Cache Valley and Bear Lake. The Wasatch Range is a intrusionsof monzonites, syenites, and diorites form the north-south oriented mountain rangethat extends from domed highlands of the Henry, LaSal and Abajo Moun- Idaho south to Salt Creek Canyon east of Nephi. The tains (Moyle 1981). The Monument and Circle Cliffs western flank is very steep and relatively straight as a uplifts and San Rafael Swell are predominantly arched result of displacement along the still active Wasatch and folded rock layers. The Great Sage Plain, south ofthe 108 RANGELANDS 14(2), April 1992 Era) basalt, andesite lava flows, and glacial deposits. Faulting generally marks the boundaries of this section with the Great Basin Section of the Basin and Range Province and the Canyon lands Section of the Colorado Plateau Province. These Boundaries are marked with colorful badlands such as Cedar Breaks and Bryce San RafaelSwell, Canyonlands Section of the Colorado Plateau Province,Emery County, Utah. LaSal Mountains, is an unusually wide and flat region unlike the surrounding area of deeply cut canyons and intrusive mountainranges (Murphy 1989b). The Kaipar- owits Plateau appears to be transitional between the Canyonlandsand the High Plateaus Sections, but the Cedar Breaks, High Plateaus Section of the Colorado Plateau marginalcliffs are erosionboundaries ratherthanfaulted Province, Iron County, Utah. boundaries like those that define the southern High Pla- Canyon. The southern boundary ofthis section is marked teaus (Murphy 198gb). The Mancos Shale Lowlands, by a series of cliffs known as the Grand Staircase. They include the Chocolate Cliffs, Vermillion Cliffs, White Cliffs, Gray Cliffs, Pink Cliffs, and Black Cliffs. Snake River-Columbia Plateau Province The Snake River-Columbia Plateau Province makes a very limited entry into Utah in the extreme northwest corner of the state. This small area includes one small basin drainingnorth from the Goose CreekMountains in Boxelder County to the Snake, and eventually, Columbia Rivers.The GooseCreek Mountains are composedof old (Paleozoic Era) to recent (Cenozoic Era) sedimentary rocks sometimes capped with volcanic ash and lava flows. Literature Cited Ash, S.R. 1981. Tectonic features. pp. 22-23. In: D.C. Greer, K.D. Gurgel, W.L. Wahlquist, H.A. Christy and G.B. Peterson. 1981. Atlas ofUtah. Weber StateCoIl, and Brigham Young Univ. Press, Provo, Utah. 300 p. Hlntze,L.F. 1975. Geological Highway Mapof Utah. Brigham Young Univ. Geol. Stud. Spec.Pub. 3. (Reprinted1984). Brigham Young MancosShale Lowlands along Interstate 70and south of the Book Utah. Plateau Province, Univ., Provo, Cliffs, Canyonlands Section of the Colorado R.W. 1981. Surfacegeology. pp. 20-21. In: D.C. Greer, K.D. Grand Utah. Moyle, County, Gurgel, W.L. Wahlquist, H.A. Christy and G.B. Peterson. 1981. south of the Book Cliffs and east of the High Plateaus, Atlasof Utah. WeberState Coil. and Brigham YoungUniv. Press, in weaker rocks. Provo, Utah. 300 p. form a fairly flat region developed Murphy, D.R. 1981.