Geology of Grand Staircase-Escalante National of...INTRODUCTION Grand Staircase-Escalante National...
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INTRODUCTIONGrand Staircase-Escalante National Monument was
established by presidential proclamation on September 18,1996 to protect an array of geological, paleontological, his-toric, archaeological, and biological resources. Followingthe creation of the monument, Congress passed the UtahSchools and Land Exchange Act, which transferred own-ership of all trust lands administered by the Utah Schooland Institutional Trust Lands Administration (SITLA)(176,699 acres) and trust mineral interests (24,000) acreswithin the monument boundaries, to the Federal Govern-ment. In exchange for these interests, and other lands andinterests within national parks and monuments in Utah,the State of Utah received title to federal lands elsewhere,mineral royalties from other federal lands in Utah, and aone-time cash payment. It is the first national monumentmanaged by the U.S. Bureau of Land Management (BLM),
incorporating the principles of the Federal Land Policyand Management Act (FLPMA). The proclamation gov-erns how the provisions of FLPMA will be applied withinthe monument. FLPMA directs the BLM to manage pub-lic land on the basis of multiple use and in a manner thatwill protect the quality of scientific, scenic, historic, eco-logical, environmental, air and atmospheric, water re-sources, and archaeological resources (U.S. Department ofInterior, 2000).
The monument covers about 1.9 million acres of landin south-central Utah (figure 1). About 68 percent of themonument is in Kane County, while the remaining 32 per-cent is in Garfield County. Conversely, about 49 percent ofKane County and 18 percent of Garfield County lie withinthe monument boundaries. The monument is primarilysurrounded on three sides by national forest and nationalpark lands, as well as other BLM administered lands to thesouth and west. Kodachrome State Park also adjoins themonument near Cannonville. For more information onmonument management and use restrictions, the readershould refer to the approved management plan (U.S. De-partment of Interior, 2000)
Geology of Grand Staircase-EscalanteNational Monument, Utah
Hellmut H. Doelling1, Robert E. Blackett1, Alden H. Hamblin2, J. Douglas Powell3, and Gayle L. Pollock4
Geology of Utahs Parks and Monuments2000 Utah Geological Association Publication 28D.A. Sprinkel, T.C. Chidsey, Jr., and P.B. Anderson, editors
1Utah Geological Survey, Salt Lake City, UT 84114-61002Fremont Indian State Park and Museum, Sevier, UT 847663Grand Staircase-Escalante National Monument, Kanab, UT 847414Bryce Canyon National History Association, Bryce Canyon National
Park, UT 84717-0002
The 1.9-million-acre Grand Staircase-Escalante National Monument was created September 18, 1996 by President Clin-ton and was the first national monument to be placed under the management of the U.S. Bureau of Land Management.Located in southern Utah, the monument contains an array of geological, paleontological, historic, archaeological, and bi-ological resources. It lies in a remote area comprised of canyons, plateaus, mesas, and cliffs set in an environment of col-orful geologic formations.
The monument is surrounded by several national and state parks, a primitive area, and a national recreation area. Itcan be divided into three geographical sections: from west to east these are the Grand Staircase, Kaiparowits Basin, and Es-calante Canyons sections. Rock formations exposed in these sections range in age from Permian to Cretaceous comprisingmore than 200 million years of Earths history. Structurally, these rocks dip gently northward, and are deformed by most-ly north-south-trending faults, anticlines, synclines, and monoclines.
The monument area contains known coal, oil and gas, and mineral resources and potential resources which are gener-ally undeveloped because market areas are distant and because ways of transporting the commodities out of the regionhave never been in place. As a national monument, the area will provide many future opportunities to study a region ofremarkably well-exposed geology.
H.H. Doelling, R.E. Blackett, A.H. Hamblin, J.D. Powell, and G.L. Pollock Geology of Grand Staircase-Escalante National Monument, Utah
Figure 1. Index map for the Grand Staircase-Escalante National Monument in Garfield and Kane Counties,
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Dixie National ForestDixie
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Paria Canyon Primitive Area
BLM, State, and private land
Towns and settlements
Figure 1. Index map for Grand Staircase-Escalante National Monument in Garfield and Kane Counties, Utah. The 1.9-million-acre monument isencircled by national parks, a national recreation area, a primitive area, and a national forest. Four state parks, Coral Pink Sand Dunes, Kodachrome,Escalante Petrified Forest, and Anasazi Indian Village State Parks are also in the area, west of Kanab, near Cannonville, near Escalante, and nearBoulder Town, respectively.
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Figure 2. Map showing the locations of the classic geologic sites (numbers) within Grand Staircase-Escalante National Monument in southern Utah.See text for descriptions of these sites. Also, the Grand Staircase section is shown in blue, the Kaiparowits Basin section in yellow, and the EscalanteCanyons section in green.
Grand Staircase-Escalante National Monument is lo-cated within the Colorado Plateau physiographicprovince, near its western margin. It is bordered by thegateway communities of Boulder, Escalante, Henrieville,Cannonville, Tropic, Glendale, Kanab, and Big Water (fig-ures 1 and 2). Annual precipitation in the region variesfrom about six inches at the lowest altitudes near LakePowell (4,000 ft), to about 25 inches at the highest altitudesnear Canaan Peak (9,280 ft). The variations in altitude andprecipitation produce three climatic zones: upland, semi-desert, and desert. At the highest altitudes, precipitationfalls primarily during the winter. The majority of precipi-tation in the semi-desert and desert areas occurs duringthe summer months.
The monument may be divided into three broad areas:from west to east these are the Grand Staircase, Kaiparow-its Basin, and Escalante Canyons sections (figure 2). TheGrand Staircase section is a broad feature that encom-passes the western third of the monument, and consists ofa series of topographic benches and cliffs that, as its nameimplies, step progressively up in elevation from south tonorth. The risers correspond to cliffs and the steps corre-spond to the benches, terraces, or plateaus in the staircase(figure 3). The bottom of the staircase commences at thetop of the Kaibab uplift, which correlates with and is in thesame stratigraphic position as the highest bench of theGrand Canyon in Arizona. The first riser above this benchis the Chocolate Cliffs, which are not well developed in theGrand Staircase section and consists of the Upper RedMember of the Lower Triassic Moenkopi Formation
capped by the Upper Triassic Shinarump Member of theChinle Formation. Descriptions of these formations aregiven in the stratigraphy section of this paper. Discontin-uous Shinarump outcrops explain why this riser is notwell developed in the monument. The next step is knownas the Shinarump Flats. This bench is mostly developedon top of the hard Shinarump Member and the overlyingsoft Petrified Forest Member of the Chinle Formation. TheVermilion Cliffs form the next riser, which is well devel-oped in the monument. The cliffs are made up of the re-sistant red sandstone beds of the Lower Jurassic Moenaveand Kayenta Formations. The Wygaret Terrace forms thenext step and includes the soft upper part of the Kayentaand the lower parts of the Lower Jurassic Navajo Sand-stone. The imposing White Cliffs form the next riser andconsist of the upper part of the Navajo Sandstone and theMiddle Jurassic Co-