Zion National Park 

Geologic Resource Evaluation Report 

Natural Resource Report NPS/NRPC/GRD/NRR—2006/014 

National Park Service 

U.S. Department of the Interior 

Natural Resource Program Center 

Zion National Park 

Geologic Resource Evaluation Report 

Natural Resource Report NPS/NRPC/GRD/NRR—2006/014 

Geologic Resources Division 

Natural Resource Program Center 

P.O. Box 25287 

Denver, Colorado 80225 

March 2006 

U.S. Department of the Interior 

Washington, D.C.
The Natural Resource Publication series addresses natural resource topics that are of interest and 

applicability to a broad readership in the National Park Service and to others in the management of 

natural resources, including the scientific community, the public, and the NPS conservation and 

environmental constituencies. Manuscripts are peer-reviewed to ensure that the information is 

scientifically credible, technically accurate, appropriately written for the intended audience, and is 

designed and published in a professional manner. 

Natural Resource Reports are the designated medium for disseminating high priority, current natural 

resource management information with managerial application. The series targets a general, diverse 

audience, and may contain NPS policy considerations or address sensitive issues of management 

applicability. Examples of the diverse array of reports published in this series include vital signs 

monitoring plans; "how to" resource management papers; proceedings of resource management 

workshops or conferences; annual reports of resource programs or divisions of the Natural Resource 

Program Center; resource action plans; fact sheets; and regularly-published newsletters. 

Views and conclusions in this report are those of the authors and do not necessarily reflect policies of 

the National Park Service. Mention of trade names or commercial products does not constitute 

endorsement or recommendation for use by the National Park Service. 

Printed copies of reports in these series may be produced in a limited quantity and they are only 

available as long as the supply lasts. This report is also available from the Geologic Resource Evaluation 

Program website (http://www2.nature.nps.gov/geology/inventory/gre_publications) on the internet, or by 

sending a request to the address on the back cover. 

Please cite this publication as: 

Graham, J. 2006. Zion National Park Geologic Resource Evaluation Report. Natural Resource Report 

NPS/NRPC/GRD/NRR—2006/014 . National Park Service, Denver, Colorado. 

NPS D-259, March 2006 
 ZION Geologic Resource Evaluation Report iii

Table of Contents 

List of Figures .............................................................................................................. iv

List of Tables ................................................................................................................ iv

Executive Summary ...................................................................................................... 1

Introduction ................................................................................................................... 2

Purpose of the Geologic Resource Evaluation Program ............................................................................................2

General Information and Regional Setting..................................................................................................................2

Park History................................................................................................................................................................2

General Geology ........................................................................................................................................................3

Geologic Issues............................................................................................................. 9

Landslides and Debris Flows......................................................................................................................................9

Earthquakes ...............................................................................................................................................................9

Volcanism.................................................................................................................................................................10

Soil ...........................................................................................................................................................................10

Impacts of Mineral Extraction ...................................................................................................................................10

Quaternary Studies...................................................................................................................................................10

Structural Geology Projects......................................................................................................................................11

Hydrogeology ...........................................................................................................................................................12

Hydrogeology Projects .............................................................................................................................................12

Paleontology and Palynology ...................................................................................................................................12

Diagenesis................................................................................................................................................................13

Identification of Type Sections..................................................................................................................................13

Geologic Features and Processes............................................................................. 17

Map Unit Properties .................................................................................................... 21

Map Unit Properties Table........................................................................................................................................23

Geologic History.......................................................................................................... 27

Tectonic History........................................................................................................................................................27

Depositional History..................................................................................................................................................28

References................................................................................................................... 36

Appendix A: Geologic Map Graphic .......................................................................... 39

Appendix B: Scoping Summary................................................................................. 41 

Attachment 1: Geologic Resource Evaluation Products CD 
 NPS Geologic Resources Division iv 

List of Figures 

Figure 1. Location map of Zion National Park ................................................................................................................4

Figure 2. Location of Zion National Park on the Colorado Plateau ................................................................................5

Figure 3. Geologic cross-section of the Grand Staircase ...............................................................................................6

Figure 4. Sketch map showing major plateaus, terraces, cliff lines, and faults .............................................................7

Figure 5. Stratigraphic column for Zion National Park....................................................................................................8

Figure 6. The distribution of young basalts in southern Nevada and southern Utah ....................................................14

Figure 7. Locations of selected geologic sites in Zion..................................................................................................20

Figure 8. Geologic time scale.......................................................................................................................................33

Figure 9. Depositional environments represented by the strata in Zion National Park.................................................34

Figure 10. Location of the Cretaceous Period, Western Interior Seaway.....................................................................35

List of Tables 

Table 1. Quaternary research projects identified in the 1999 Workshop......................................................................15

Table 2. Potential research projects identified in the 1999 Workshop at Zion..............................................................16
 ZION Geologic Resource Evaluation Report 1

Executive Summary 

This report has been developed to accompany the digital geologic map produced by Geologic 

Resource Evaluation staff for Zion National Park. It contains information relevant to 

resource management and scientific research. 

The spectacular cliffs, arches, spires, temples, and 

colorful strata of Zion National Park record changing 

environmental conditions through 275 million years of 

geologic time. Zion lies in a transition zone where the 

High Plateau region of the Colorado Plateau meets the 

Basin and Range geological province. A visitor to Zion 

enters a landscape in which the rock layers have been 

arched upward, tilted, and eroded into plateaus and 

terraces that form a giant staircase stepping up from the 

Grand Canyon to the south northward to Bryce Canyon 

National Park. Under foot, the strata record episodes of 

both horizontal compression caused by colliding 

lithospheric plates and extensional tectonics generated 

as the lithospheric plates pulled away from one another. 

The heterogeneous strata of primarily Mesozoic and 

Cenozoic rocks in the park present potential geologic 

hazards that fall into five general categories: 

• Landslide and debris flows 

• Earthquakes 

• Volcanism 

• Soil instability 

• Impacts of mineral extraction 

Landslides and debris flows occur in both consolidated 

and unconsolidated material. Landslides pose a potential 

hazard especially during and after rainstorms. Erosion 

and construction projects that oversteepen slopes or 

undercut cliffs also promote potential landslides. 

The potential for damage caused by earthquakes and 

volcanism is not well defined for Zion. The Hurricane 

Fault remains active with long- term slip rates of 0.21 to 

0.57 mm/year and is capable of producing earthquakes of 

magnitude 6- 7. Many relatively small episodes of 

volcanism have occurred in southwestern Utah in recent 

geologic times. Although there are no indications of 

imminent eruptions, it is possible that the Zion area will 

experience some level of volcanic activity in the future. 

Soils composed of expandable clays present potential 

construction and maintenance issues for Zion. Areas 

containing these types of soils need to be identified. 

Radon in the soils is another potential problem. A 

naturally occurring radioactive gas, radon has been 

identified in soils developed on the Chinle Formation. 

An abandoned uranium mine and three abandoned oil 

wells within park boundaries may pose issues in the 

future. Both types of operations may impact 

groundwater and surface water. Tailing piles also present 

a possible air quality issue. 

Based on these issues and specific properties attributed 

to the geologic formations found in Zion, a list of 

potential research projects was generated during a 

Geologic Resource Inventory Workshop held at Zion in 

1999. Project topics fell into the following general list: 

• Quaternary studies 

• Structural geology projects 

• Hydrogeology projects 

• Palynology 

• Diagenesis 

• Identification of type sections 

These research projects focus on the properties tied to 

individual formations and the relationship between 

strata. Erosion potential is high in Quaternary sediments, 

for example, and also in sandstone units with high 

porosity and permeability. The Navajo Sandstone and 

some alluvium act as aquifers, which need to be 

monitored and studied for water yields, water quality, 

and potential contamination. Other units, especially in 

the Kaibab Limestone, are prone to karst development as 

calcium carbonate dissolves in meteoric groundwater 

percolating downward through porous formations or 

along vertical fractures in the rock. There may be an 

opportunity to locate and preserve a type locality for the 

Navajo Sandstone. Fossils and archeological artifacts 

may be associated with features common to certain 

geological units. 

Zion has many geologic features that formed in response 

to geologic processes that continue to modify the current 

landscape. Geologic processes that form canyons also 

promote landslides and illustrate the complex 

relationship among strata, fractures, and climate. 

Weathering processes have produced distinctive patterns 

in cross- bedded sandstone. Hanging valleys and alcoves 

color the sandstone cliffs. Narrow slot canyons have 

been cut into bedrock. Dinosaur tracks are preserved in 

sandstone. The Kolob arch, the world’s longest natural 

arch, spans a distance of 94.5 m (310 ft). All the 

monoliths, canyon walls, and other geologic resources 

combine to provide a visitor to Zion with an exceptional 

experience. 
 NPS Geologic Resources Division 2 

Introduction 

The following section briefly describes the regional geologic setting and the National 

Park Service Geologic Resource Evaluation Program. 

Purpose of the Geologic Resource Evaluation Program 

Geologic resources serve as the foundation of park 

ecosystems and yield important information for park 

decision making. The National Park Service Natural 

Resource Challenge, an action plan to advance the 

management and protection of park resources, has 

focused efforts to inventory the natural resources of 

parks. The geologic component is carried out by the 

Geologic Resource Evaluation (GRE) Program 

administered by the NPS Geologic Resources Division. 

The goal of the GRE Program is to provide each of the 

identified 274 “natural area” parks with a digital geologic 

map, a geologic evaluation report, and a geologic 

bibliography. Each product is a tool to support the 

stewardship of park resources and each is designed to be 

user friendly to non- geoscientists. 

The GRE teams hold scoping meetings at parks to review 

available data on the geology of a particular park and to 

discuss the geologic issues in the park. Park staff are 

afforded the opportunity to meet with the experts on the 

geology of their park. Scoping meetings are usually held 

in each park individually to expedite the process 

although some scoping meetings are multipark meetings 

for an entire Vital Signs Monitoring Network. 

General Information and Regional Setting 

Protected within the 593 square kilometers (229 square 

miles) of Zion National Park, the Kolob Arch is the 

world’s largest arch with a span measuring 94.5 m (310 ft), 

a window height of 101 m (330 ft), and a thickness of 24 m 

(80 ft) (Biek et al. 2000). In other monuments and parks, 

this arch would be the centerpiece of a visitor’s 

experience, but Zion is probably best known for Zion 

Canyon. This narrow chasm with sheer walls of Navajo 

Sandstone towering 610 m (2,000 ft ) above the canyon 

floor contains blind arches, alcoves, hanging valleys, 

waterfalls, and colorful surficial stains (desert varnish). 

Incised into Zion Canyon, the Virgin River is one of the 

last, mostly free- flowing river systems on the Colorado 

Plateau. About 2,130 m (7,000 ft ) of sedimentary rock 

records approximately 275 million years of changing 

environmental conditions in Zion. 

Zion National Park is located in the semi- arid desert of 

southwestern Utah. Interstate 15 passes west of Zion and 

connects with Utah 9 leading to the park (figure 1). U.S. 

89 passes east of the park and connects with Utah 9 to 

the park. 

The lowest elevation in the park is 1,128 m (3,7oo ft) 

above sea level at Coalpits Wash in the southwestern 

corner of the park while the highest is 2,660 m (8,727 ft ) 

above sea level at Horse Ranch Mountain in the Kolob 

Canyons section. 

Park History 

The rugged, dissected topography of the Zion region 

presented a formidable impediment to early visitors to 

the region. During the Formative period (A.D. 500-

1300), two distinctive horticultural groups, the Virgin 

branch of the Ancestral Puebloan (formerly Virgin 

Anasazi) and the Parowan Fremont, settled in the area of 

Zion National Park. Datable artifacts suggest that 

Ancestral Puebloan people occupied the southern part of 

the present park about 750 A.D. while the Parowan 

Fremont people settled the valleys and plateaus north 

and west of the park (Eardley and Schaack 1994; Kiver 

and Harris 1999). The difference between the Ancestral 

Puebloans and the Fremont cultures can be attributed to 

geography of their settlements (Dave Sharrow, National 

Park Service – Zion National Park, personal 

communication). Both cultures settled around water 

courses where they occurred, both also left artifacts in 

upland settings. When the Little Ice Age changed climate 

patterns about 1200 A.D., crops failed and this area and 

other drier sites on the Colorado Plateau were 

abandoned. 

The historic period began in the eighteenth century 

when initial explorations by traders from New Mexico 

blazed the Old Spanish Trail. During the nineteenth 

century, the temples and canyons became familiar to the 

Paiutes who settled this unoccupied land. They 

compared the canyon of the Virgin River and its 

tributaries in the Zion area to a “loogoon,” or quiver of 

arrows in which one comes out the way it goes in (Kiver 

and Harris 1999). 

Once the Mormon settlement of the Great Salt Lake area 

was established in 1847, Brigham Young sent scouts and 

settlers into the area to seek out arable land and potable 

water. Small communities sprang up along the Virgin 

River during the 1860s following Nephi Johnson’s 

exploration of the Great White throne in 1858. Issac 

Behunin built the first log cabin in Zion Canyon on the 

fine- grained lake sediments near today’s Zion Lodge. 

Amidst the grandeur and beauty of the spectacular white 

and pink monoliths and canyon walls, Behunin and the 

few other Mormon settlers felt as if they were 

surrounded by a great cathedral or heavenly place. 

Behunin called the place Little Zion. 

Two scientific surveys, the Wheeler Survey and the 

Powell Survey, were the first professional surveys to 

investigate the region in the nineteenth century. The 

Wheeler Survey (1869- 1871) focused on generating a 

master topographic atlas of the west rather than studying 
 ZION Geologic Resource Evaluation Report 3

geology. No geologists were involved in the Wheeler 

survey until the third field season in 1871 when Grove 

Karl Gilbert joined (Gregory 1950; Stegner 1954). 

When Gilbert joined the Powell survey in 1874, he was 

allowed great freedom to study the geology of the west. 

Consequently, Gilbert’s systematic observations and 

documentation of the geology of the High Plateau 

country remain relevant today. 

Clarence Edward Dutton, another geologist who joined 

Powell’s survey in 1875, studied the structure and igneous 

history of the High Plateaus (Gregory 1950). With 

geologists like Gilbert, Dutton, William H. Holmes, and 

Charles D. Walcott, the Powell Survey set an elevated 

standard for the study of geology in America. New 

geological principals were established, old ones were 

revised, and illustrations defined processes, structure, 

and topographic forms of the High Plateaus and Canyon 

Country of Utah. 

Major John Wesley Powell visited the southern Utah 

region and used the Native American name 

Mukuntuweep, which means “straight canyon”, to 

describe the spectacular canyon along the upper Virgin 

River (Kiver and Harris 1999). Photographs and drawings 

from Powell’s expedition ignited the public’s interest in 

these magnificent canyons, rounded domes, arches, and 

monoliths and spurred the eventual protection of the 

area in 1909 when the region became Mukuntuweap 

National Monument. 

The name “Mukuntuweap” was not popular with the 

non- Native American locals, who, like Behunin, 

considered the grandeur and beauty of the spectacular 

white and pink monoliths and canyon walls to be 

reminiscent of a great cathedral or heavenly place. The 

name was subsequently changed to Zion National Park 

in 1919. The Kolob section was added in 1937, bringing 

the park to near its present size. 

General Geology 

Zion is located at the western margin of the Colorado 

Plateau, a physiographic province characterized by high 

plateaus and broad, rounded uplands separated by vast 

rangelands covering parts of Colorado, Utah, Arizona, 

and New Mexico (figure 2). The Colorado Plateau is 

distinctive in that the sedimentary rocks forming the 

plateau, while having been folded and faulted in places, 

remain much more intact than in surrounding areas. 

Also, the Colorado Plateau province contains the highest 

concentration of parklands in North America. The cliffs 

and rock temples of Zion are part of the High Plateau 

section of the Colorado Plateau and it is located near the 

transition zone between the Colorado Plateau and Basin 

and Range physiographic provinces. 

The rocks of the Colorado Plateau have been arched 

upward, tilted, and eroded into a feature called the 

Grand Staircase (figure 3). The first step, in the Grand 

Canyon, is composed of Precambrian- age rocks, the 

oldest rocks exposed on the Colorado Plateau. Paleozoic 

rocks in the Grand Canyon step up to Triassic- age rocks 

of the Chocolate Cliffs (Moenkopi Formation and 

Shinarump Conglomerate) and Vermillion Cliffs (Chinle 

Formation and Wingate Sandstone or locally the lower 

Navajo Sandstone), then up to the Jurassic- age White 

Cliffs (upper Navajo Sandstone) at Zion (Kiver and 

Harris 1999). The Pink Cliffs of Bryce Canyon National 

Park top the giant staircase with Cenozoic layers of rock 

(figure 3). The lowest (oldest) rock layer found at Bryce is 

the top (youngest) layer at Zion, and the lowest (oldest) 

step at Zion is the top (youngest) layer at the Grand 

Canyon. 

Two platforms, each thousands of square miles in area, 

dominate the topography in the Zion region (figure 4). 

The lower platform to the south consists of the Uinkaret 

and Kanab Plateaus. These plateaus border the Colorado 

River in Arizona forming the rims of Grand Canyon 

(Gregory 1950). 

Between these large plateaus the Vermillion Cliffs of 

Navajo Sandstone and Kayenta Formation form a major 

step. Zion Canyon is cut into the face of this step and the 

Kolob Terrace sits on top of it (figure 4). The Kolob 

Terrace is relatively well watered by springs and streams 

and more accessible than the highest plateaus, making it 

a desirable summer range for sheep and cattle. 

Zion is primarily a Mesozoic park (figure 5). The arid 

climate and sparse vegetation allow exposure of vast 

expanses of colorful sedimentary strata ranging in age 

from the Early Permian Toroweap Formation to the 

newly recognized late Cretaceous strata. The most 

abundant rock is sandstone. The cliffs, benches, terraces, 

and shelves on slopes are composed of massive 

sandstone. Except for the coarser grained conglomeratic 

sandstone in the Shinarump Formation of Triassic age 

and the Cretaceous Dakota Formation, sandstones in 

Zion are generally fine or medium grained (Gregory 

1950). Beds roughly classified as “shale” are, in fact, 

relatively thin beds of very fine grained sandstone rather 

than true clay shale. Likewise, the rocks classified as 

“limestone” could be as easily classified as “calcareous 

sandstone.”
 NPS Geologic Resources Division 4 

Figure 1. Location map of Zion National Park. 
 ZION Geologic Resource Evaluation Report 5

Figure 2. Location of Zion National Park on the Colorado Plateau, showing some of the significant uplifts, basins, faults, volcanic 

centers, and rivers. High areas are shown in gray: AM, Abajo Mts.; AP, Aquarius Plateau; BC, Book Cliffs; CCU, Circle Cliffs Uplift; DU, 

Defiance Uplift; KU, Kaibab Uplift; LSM, La Sal Mts.; MU, Monument Upwarp; RC, Roan Cliffs; SRS, San Rafael Swell; UU, 

Uncompahgre Uplift. Basins: PB, Paradox Basin; UB, Uinta Basin. Leading edge of Sevier Thrust Belt is shown with sawteeth on 

upper, overriding thrust plate. Modified from Kiver and Harris, 1999. 
 NPS Geologic Resources Division 6 

Figure 3. Geologic cross-section of the Grand Staircase from the Grand Canyon to Bryce Canyon National Park and Cedar Breaks 

National Monument. Diagram illustrates the lithologic correlation from south to north. Modified from the geologic cross section

published by the Zion Natural History Association, 1975. 
 ZION Geologic Resource Evaluation Report 7

Figure 4. Sketch map modified from Gregory (1950) showing the location of Zion NP and the position of the major plateaus, terraces, 

cliff lines, and faults in the Zion region. ZION: Zion National Park; BRCA: Bryce Canyon National Park; CEBR: Cedar Breaks National 

Monument; PISP: Pipe Spring National Monument. 
 NPS Geologic Resources Division 8 

Figure 5. Stratigraphic column for Zion National Park. 
 ZION Geologic Resource Evaluation Report 9

Geologic Issues 

A Geologic Resource Evaluation scoping session was held for Zion National Park April 

12- 13, 1999, to discuss geologic resources, to address the status of geologic mapping, and 

to assess resource management issues and needs. The following section synthesizes the 

scoping results, in particular, those issues that may require attention from resource 

managers. 

Details correlating geologic units to specific park 

concerns were not defined in the summary report 

documenting the 1999 workshop. However, significant 

geologic hazards in Zion were identified. The issues 

identified at the workshop fall into the following 

categories: 

• Landslide and debris flow issues 

• Earthquake issues 

• Volcanism 

• Soils 

• Impacts of mineral extraction 

Landslides and Debris Flows 

Landslides and rockfalls are common occurrences in 

Zion Canyon and the rest of the park. A “landslide” is a 

general term for any mass movement of material, 

consolidated or unconsolidated. Landslides are 

prevalent in Zion because the rapid cutting of a deep 

canyon exposes large cliff faces and slopes to the force of 

gravity, and many overlying beds rest on strata that are 

notoriously weak. Landslides and rockfalls are 

particularly prone to occur during and after rainstorms, 

or in particularly wet seasons. 

The Navajo Sandstone is a relatively friable sandstone 

containing abundant joints and therefore, has a high 

erosion potential along fractures and joints. Many of the 

sandstones in Zion are underlain by shale or siltstone 

and are prone to undercutting which may lead to 

landslides and rockfalls. 

The North Fork of the Virgin River continues to erode 

and oversteepen the 180 m (600 ft) high face of Sand 

Bench. This process has caused periodic reactivation of 

older landslide material at Sand Bench in the stretch of 

Zion Canyon located beneath The Sentinel (Biek et al. 

2000). Major landslides were documented in 1923, 1941, 

and 1995. 

The most recent significant landslide in Zion occurred 

on April 12, 1995. At about 9:00 pm, the lower face of 

Sand Bench gave way and a landslide dammed the North 

Fork of the Virgin River. The landslide mass was about 

150 m (500 ft) long and 45 m (150 ft) wide and transported 

about 84,000 cubic meters (110,000 yd3

) of material. A 

6- m (20- ft) deep pond formed that eventually 

overtopped the landslide dam. Although no flooding 

occurred downstream, the river eroded a 180 - m (600 -

ft) section of the east bank, washing out Zion Canyon 

Scenic Drive (Biek et al. 2000). Two days later, a 

temporary access road was opened on the east side of the 

river for the more than 300 people stranded at Zion 

Lodge. Excessive precipitation in the preceding months 

has been blamed for the landslide by elevating pore 

pressures and reducing cohesion within the landslide 

mass. The winters of 1995, 1941, and 1923 that preceded 

major slides were all exceptionally wet. 

Several landslide deposits are mapped in and around the 

community of Springdale. These deposits can be 

recognized by tipped and broken strata and irregular 

hummocky terrain. These slides have all occurred where 

overlying strata slid on the weaker, more plastic Petrified 

Forest member of the Chinle Formation. One of the 

largest recent slides is located just outside the entrance of 

Zion National Park, and was triggered by a December 2, 

1992 magnitude 5.8 earthquake centered on the 

Washington Fault, about 48 km (30 mi) southwest. Three 

houses recently built on these slopes were destroyed 

when the slope dropped 30 m (98 ft) and extended 

laterally a similar distance over a period of several hours. 

Landslide deposits (Ql) are identified on the geologic 

map (Appendix A and Attachment 1). These areas should 

be monitored for movement. In addition, old landslides 

should be studied in detail to determine the size of 

material moved, the cause of movement, the porosity and 

permeability of the medium involved in the movement, 

and the degree of saturation prior to movement. The 

degree of slope and the potential and real downhill 

impacts from mass movements should also be 

documented and inventoried. 

Construction or maintenance could potentially cause 

mass movements, therefore roads and other facilities 

should be constructed over landslide deposits with the 

greatest caution. 

Earthquakes 

A 1992 earthquake scarp in Springdale can be seen at the 

west entrance of the park. Significant Quaternary offset 

suggests that the Hurricane fault zone remains an active, 

north- trending, west- dipping normal fault in the Kolob 

Canyons area (Biek et al. 2000). The fault zone stretches 

for at least 250 km (155 mi) from south of the Grand 

Canyon northward to Cedar City. The fault has been 

divided into two segments near Zion, the Ash Creek 

segment and the Anderson Junction segment. Two short 

lengths of the Ash Creek segment are in Zion. These 

segments are visible at the mouths of Taylor Creek and 
 NPS Geologic Resources Division 10 

Camp Creek. At both of these localities, the fault is 

defined by the juxtaposition of Permian Harrisburg and 

Triassic lower Moenkopi strata on the upthrown block 

against basin- fill, unconsolidated sediments on the 

downthrown block. Fault drag has folded the strata on 

the upper block. At St. George, the tectonic displacement 

along the fault is about 1,098 m (3,600 ft), and near the 

latitude of Toquerville, the displacement is about 1,494 m 

(4,900 ft) (Biek et al. 2000). Near the Kolob Canyons 

area, the average slip rate for part of the Ash Creek 

segment is about 0.39 meters/1,000 years (15 in/1,000 yr). 

The Hurricane Fault marks the western boundary of the 

Kolob Canyon section. 

The Hurricane Fault may be the only active fault in the 

park. Movement along other faults in the park could be 

measured by a seismic monitoring system. Possible 

sources for earthquakes such as groundwater 

withdrawal, artificial recharge, oil extraction, or tectonic 

plate movements could be identified and monitored. 

If the fault trace indicates the direction of movement, the 

type of fault could be determined. 

Volcanism 

Though volcanism is not widespread in the area, 

numerous smaller lava flows have occurred in the 

vicinity in the recent geologic past. Thirteen lava flows 

are mapped in and near Zion dating from 1.5 million to 

100,000 years ago. More recent flows of less than 10,000 

years in age occurred north of Zion and east of Cedar 

Breaks National Monument. Thus the occurrence of 

sporadic volcanism can be said to be continuing in the 

area, but on a human time scale it is more important as a 

part of the geologic story of Zion than an actual threat. 

Figure 6 shows the larger patterns of volcanism over the 

last 15 million years. 

Soils 

The Triassic Chinle Formation contains the expandable 

clay, bentonite, formed from volcanic ash. Bentonite has 

the unique property of incorporating water molecules 

into its chemical structure and expanding. Upon drying, 

the structure collapses causing the clay to shrink. This 

shrink and swell property can have an undesirable effect 

on roads, buildings, and infrastructure resulting in 

maintenance and construction problems due to unstable 

soils. 

 Soils derived from Chinle Formation should be located 

and analyzed for their bentonite content, the slope upon 

which they rest, and their water- holding capacity. If 

possible, areas containing these soils should be avoided 

when planning future development. Bentonite soils have 

also been found on terraces soils derived from sheet flow 

off of the Moenave Formation. 

Radon is present in soils developed upon the Chinle 

Formation. Radon is a naturally occurring radioactive gas 

(the only radioactive gas) produced by the radioactive 

decay of Uranium (U) and Thorium (Th). Radon is 

colorless, odorless, and tasteless and usually associated 

with high concentrations of U. High levels of U may be 

found in granitic rocks, stream sediments, groundwater, 

or surface waters. Weathering and re- sedimentation may 

also concentrate U. Faults and shear zones are more 

permeable and therefore may be enriched with U and 

consequently elevated levels of radon gas may be present 

in the overlying soils. 

The movement of radon through rocks and soil depends 

upon the pore space and permeability of the medium 

through which the gas flows. Radon is moderately 

soluble in water and can be transported over 

considerable distances. Fluid transport is especially rapid 

in limestone and along faults. Radon may enter a building 

from the ground or via the water supply, especially if the 

building is supplied by a well. 

Park staff may wish to inventory and monitor the amount 

of radon associated with faults, soils, and rocks in the 

park. The radon potential of an area can be estimated by 

soil gas surveys. A soil gas survey should be conducted in 

stable weather conditions because weather conditions as 

well as soil permeability affect radon detection levels. 

Both must be taken into account during a soil gas survey. 

The data from soil gas surveys can be used to produce 

maps that show levels of radon in the soil. Different 

methods may be used to measure and monitor the level 

of radon in soils. An active monitoring method is a 

hollow spike hammered into the ground and linked to a 

gas pump and detection unit. A passive method would be 

to bury radon detectors in the soil for later recovery. 

Impacts of Mineral Extraction 

Federal mineral leasing is prohibited within the 

boundaries of Zion National Park as is the location of 

new mining claims. Approximately 3,500 acres in the 

park are non- federally owned and could potentially be 

the subject of proposals to develop private mineral 

rights. If that occurred, the NPS would regulate that 

activity. However, no mineral production on this acreage 

is taking place at this time. In addition, park resources 

and visitor values could be adversely affected by mineral 

development adjacent to the boundary of the park. 

Interest in exploiting mineral resources in southwest 

Utah has been active since 1851 when large deposits of 

iron and coal were found near Cedar City (Gregory 

1950). Most of the prospect holes and milling tests, 

however, have not been encouraging to commercial 

mining operations. Widely scattered, small, impure 

deposits of copper have been discovered in the Kaibab 

Limestone and the Navajo Sandstone. Lead, zinc, silver, 

gold, manganese, and uranium are all found in the Chinle 

Formation. Building stone is also available as a potential 

resource. 

An abandoned uranium mine is located on private lands 

approximately 100 feet outside the park boundary near 

the Kolob Canyon Visitor Center. An evaluation of the 

site was made by a NPS- GRD geologist in 1991 

(Burghardt 1991). Potentially hazardous mine openings 

exist at the site, but since these are located on patented 

mining claims it is the responsibility of the claimant and 
 ZION Geologic Resource Evaluation Report 11

the State of Utah to mitigate these hazards. Nevertheless, 

park staff should be aware of these hazards and 

discourage entry. 

Coal was found by Mormon pioneers in Coal Creek 

Canyon and on Cedar Mountain north of Zion. In the 

Zion region, coal is found in Cretaceous formations. 

Deposits that are thick enough to mine are found in the 

Tropic Formation, a Cretaceous formation that is not 

exposed in the park, but is exposed on the slopes of the 

watershed above the park. Despite protection from 

development in Zion, coal mining operations in 

southwest Utah may impact the viewshed of the park and 

thus, the visitor’s experience. Acidic precipitation, over 

time, would also impact the geological features of the 

landscape. 

Sand and gravel in various amounts are available in 

alluvial deposits in and near Zion. Although sand and 

gravel extraction is prohibited in the park, mining 

operations would target the more abundant deposits 

outside the park. Park staff should have a map of these 

deposits if one is not already available. 

Pioneer settlers and Paiute Indians knew about the oil 

seeps in Oil Seeps Wash, on North Creek and in cavities 

filled with “oily tar” in rocks in the La Verkin, Virgin, 

and Short Creek Valleys (Gregory 1950). Oil exploration 

began in 1907 and resulted in the Virgin Oil field located 

approximately 3 miles west of Zion National Park. The 

Virgin Oil Field is Utah’s oldest oil field, but was never a 

big producer. It was abandoned in the late 1960’s after 

producing over 200,000 barrels of oil. Oil came from thin 

beds of sandy limestone in the Timpoweap member of 

the Moenkopi Formation, which occurs at depths less 

than 600 feet in the field. Lack of trapping mechanisms 

and indications of oil degradation from exposure to 

oxygenated ground water, bacteria, and other nutrients 

limit future potential for the Timpoweap in the area of 

Virgin. However, the deepest well drilled in the Virgin 

Field, the Bardwell No. 1 Venton, bottomed out at 4,538 

feet in the Mississippian and had several good shows in 

the base of the Permian at 3,410 to 3,490 feet." 

Though the area around Zion contains all the elements 

necessary for oil and gas accumulations (source rocks, 

reservoirs, and trapping mechanisms), past exploration 

results have been poor. However, advances in 

exploration technology supported by higher product 

prices and demand could renew interest in the area. 

Since much of southwest Utah consist of federal lands, 

the Bureau of Land Management would be a good source 

of information on the industry’s level of interest at any 

given time. 

In 2001 the Bureau of Land Management proposed the 

issuance of oil and gas leases for the exploration and 

production of coalbed methane north of the park in the 

Virgin River Watershed near the headwaters of the 

North Fork of the Virgin River and its major tributary 

Deep Creek. At the request of the NPS, the BLM 

withdrew the leases from sale at that time. In 2005, BLM 

consulted with Zion NP on the sale of additional leases 

located immediately north of the park boundary, just east 

of Interstate 15. Due to NPS concerns over viewshed and 

steep slope issues, BLM also removed these leases from 

the sale. Limited oil and gas leasing has taken place in the 

Virgin River watershed further to the north and east of 

Zion. However, exploration in these sites has not 

resulted in the production of oil and gas (Dave Sharrow, 

Zion National Park, personal communication 2005). 

Three abandoned oil wells exist within the park. If wells 

are not plugged properly, there may be a conduit for well 

fluids (oil, brine, etc.) to mix with groundwater and 

present a water quality problem. Consequently, the park 

may benefit from knowing: 

• the depths wells were drilled and oil zones 

encountered, 

• the drilling, production, and plugging history of the 

specific wells and the operations (i.e., depth of casing 

and cementing record) if available, or general practices 

of the time if specific well records do not provide the 

details, 

• groundwater flow and depth in the area, and 

• proximity and water quality of existing water wells. 

Other issues and potential research projects include: 

• Quaternary studies 

• Structural geology projects 

• Hydrogeology 

• Paleontology and Palynology 

• Diagenesis 

• Identification of type sections 

Quaternary Studies 

Quaternary research projects fall into four general topics: 

lake studies, fluvial and alluvial projects, landslides, and 

ecosystem management. The 1999 workshop list of 

research projects involving these Quaternary projects is 

summarized in table 1 (a subset of table 2). 

Structural Geology Projects 

Two projects associated with structural geology were 

identified in 1999: 

• determining the history of the Hurricane fault as 

related to Basin and Range extension 

• developing a history of joint formation 

Both of these projects would help project future 

landslides and cliff collapse as well as slippage along the 

active Hurricane fault zone. Because oil exploration may 

also impact the park (either directly or indirectly by 

impacting the viewscape), studies pertaining to structural 

hydrocarbon traps might also prove fruitful. 
 NPS Geologic Resources Division 12 

Hydrogeology 

Aquifer Potential 

Most precipitation in the semi- arid Zion region runs off 

the hard, poorly vegetated surface. If it wets the soil, it is 

captured by plants and evaporates from the leaves. Such 

conditions are not favorable for the accumulation of 

groundwater. About 10 percent of rain and snowmelt 

seeps into groundwater aquifers. Several formations have 

the necessary porosity and permeability to accommodate 

this percolating groundwater. 

The Navajo Sandstone serves as the principal aquifer in 

the region. Large recoverable reserves of excellent 

groundwater quality are present in the Navajo Sandstone 

(Gregory 1950; Cordova 1978; Clyde 1987). Porosity of the 

Navajo Sandstone ranges from 32% on neutron logs run 

in groundwater wells to 17% from rock samples analyzed 

in the laboratory. Because the Navajo Sandstone is 

exposed at the surface, the aquifer is considered to be an 

unconfined aquifer. Sandstones in the Carmel, Kayenta, 

Moenave, Chinle, and Moenkopi formations and the 

Kaibab Limestone also contain recoverable quantities of 

groundwater but these aquifers may be confined 

between impermeable strata. 

Where impervious shales, limestones, and mudstones 

inhibit upward or downward flow of groundwater in the 

more porous sandstones, the water escapes laterally. If 

the aquifer is exposed at the surface springs or seeps 

develop. Consequently, the contact between the Navajo 

Sandstone and underlying, less permeable Kayenta 

Formation is often marked by springs or seeps. Clyde 

(1987) provides location maps for both springs and wells 

in the Virgin River basin. 

Alluvial aquifers located in unconsolidated, narrow 

valley- fill sediments along major drainages are a primary 

source of water for irrigation in the area (Gregory 1950; 

Clyde 1987). Loose unconsolidated material ranges from 

near zero to 61 m (200 ft) in depth. The water table is 

usually high and groundwater is easily recovered through 

shallow wells. Deeper, more extensive alluvial aquifers 

are also found in the Virgin River basin that may extend 

to 152 m (500 ft). Local aquifers have also been defined in 

Quaternary basalts and thin sandstone units in the 

Cretaceous Dakota Sandstone and the sandstone lenses 

in the Chinle Formation. 

Contour maps of groundwater flow are presented in 

Cordova (1978) and Clyde (1987). The general pattern of 

groundwater flow follows the surface topography and 

surface water runoff from higher elevations towards the 

drainage network of the Virgin River and its tributaries. 

Of course, groundwater movement may be extremely 

variable, especially with regard to confined aquifers. 

Some groundwater will move vertically through 

permeable and semi- permeable layers while some 

groundwater will move horizontally due to an 

impervious barrier and emerge as a spring or seep. Faults 

can also complicate groundwater flow. Some faults act as 

barriers to groundwater flow; some act as conduits 

(Cordova 1978; Clyde 1987). 

Groundwater aquifers are naturally recharged in the 

Upper Virgin River Basin by the infiltration of 

precipitation (some directly and most from melting 

snow) and seepage from streams passing over recharge 

areas of the aquifer outcrops. Much of the recharge takes 

place at higher elevations where precipitation is greater. 

Development of recharge areas may impact groundwater 

levels. A more thorough description of groundwater 

recharge and discharge properties in the Navajo 

Sandstone is presented in Cordova (1978) and Clyde 

(1987). 

Hydrogeology Projects 

Because water is the most precious resource in a desert, 

the groundwater studies listed below would have a direct 

impact on the future development of water resources in 

the park. Experts in the Water Resources Division of the 

NPS and the USGS should be consulted regarding the 

following groundwater issues: 

• hydrologic parameters near the Sevier fault zone east 

of Zion 

• fracture flow in the Navajo Sandstone aquifer 

• groundwater quality and quantity related to joints 

• locations of hydrologic divides in Zion to determine 

groundwater flow patterns. 

Groundwater (GW) Quality 

Most of the springs in the Zion region yield water that is 

relatively low in mineral content. Generally, the longer 

groundwater is in contact with surrounding rock, the 

higher its mineral content will be. Springs that feed Oil 

Seeps Wash and Alkali Wash are also gypsiferous and 

may taste of oil (Gregory 1950). Otherwise, groundwater 

is generally fresh while some is fresh to slightly saline. 

Paleontology and Palynology 

The Utah Geological Survey completed a Survey of the 

paleontological resources of Zion National Park in 2005 

(De Blieux et al. 2005). Among the paleontological 

resources found in the park are bones, plant materials 

and imprints, tracks, burrows and other trace fossils, 

wood, invertebrates, fish, and Quaternary tracks. The 

abundance of fossils varies considerably by strata from 

absent to abundant. 

Palynology is the study of pollen and spores whether 

living or fossil. The research projects listed in the 1999 

scoping summary (Appendix B) included a proposal to 

investigate the palynology of various formations. 

Although specific formations were not identified, the 

formations associated with recent lake deposits and 

younger bedrock formations containing strata deposited 

under terrestrial conditions probably have the better 

chance for preserved pollen than do ancient marine 

environments or older formations that were buried to 

depths wherein the pollen was destroyed by heat, 

pressure, and chemical reactions. 
 ZION Geologic Resource Evaluation Report 13

Diagenesis 

Diagenesis is the study of physical and chemical 

processes that change the sediment upon deposition and 

burial. These processes may include compaction, 

cementation, recrystallization, and replacement of one 

mineral for another. Two diagenetic projects identified 

during the 1999 scoping meeting (Appendix B) are: 

• dating desert varnish 

• determining the effects of cementation on the color in 

rocks with emphasis on groundwater from the Navajo 

Sandstone and diagenesis 

These two topics might make an interesting story for the 

interpreters at Zion, but park resource staff may also 

wish to know the diagenetic affects controlling porosity 

and permeability in potential hydrocarbon reservoirs 

that lie in the vicinity of Zion. Diagenetic histories are 

complex, but they may be used to project whether a 

potential rock unit is a reservoir, for hydrocarbons or for 

groundwater. Diagenetic studies may also be used to 

estimate erosion rates and potential slippage along fault 

and joint planes. 

Identification of Type Sections 

Geologic formations typically have a designated locality 

at which the formation was first described and named. 

The Navajo Sandstone, however, does not have a 

designated type locality (USGS Lexicon web site). 

Rather, the formation was named for the “Navajo 

Country” of Arizona, Utah, and New Mexico. Zion 

National Park could serve as a type locality for the 

Navajo Sandstone, and thus, the type locality would be 

preserved. Table 2 summarizes the 1999 Workshop list of 

potential research projects (Appendix B). 
 NPS Geologic Resources Division 14 

Figure 6. The distribution of young basalts in southern Nevada and southern Utah and their approximate ages. The ages systematically 

decrease from west to east suggesting the presence of a fixed hot spot in the mantle. Modified from Fillmore, 2000, and Nelson and 

Tingey, 1997. 
 ZION Geologic Resource Evaluation Report 15

TABLE 1. Quaternary research projects identified in the 1999 Workshop. 

Quaternary Topic Research Project 

1. Lake development and climate history 

2. Analyze cores taken to the bottom of lake deposits including the core collected by 

 Helmutt Doelling (UGS) Lake studies 

3. Determine lake chronology using lake sediments 

1. Alluvial terrace chronology 

Fluvial/alluvial 

2. River system erosion history with emphasis on upstream basalts 

Landslides History of slope instability from landslides (age of landslides) 

1. Correlations between vegetation types and rock types 

Ecosystem mgmt. 2. Ecological analysis of pack- rat middens 

3. Study of coalpits lakebed deposits 
 NPS Geologic Resources Division 16 

TABLE 2. Potential research projects identified in the 1999 workshop at Zion. 

Category Potential Research Project 

Lake development and climate history 

Analyze any cores collected from lake deposits 

Determine lake chronology using lake sediments 

Alluvial terrace chronology 

River system erosion history with emphasis on upstream basalts 

History of slope instability from landslides (age of landslides) 

Correlations between vegetation types and rock types 

Ecological analysis of pack- rat middens 

Quaternary Studies 

Study of coal pit deposits 

Determine the history of the Hurricane fault/Basin and Range extension 

Structure Projects 

Relate joint formation in Navajo Sandstone to regional tectonics 

Hydrologic parameters near the Sevier fault zone east of Zion 

Fracture flow in the Navajo Sandstone aquifer 

Groundwater quality and quantity related to joints 

Hydrogeology 

Locations of hydrologic divides in Zion vicinity 

Palynology Palynology of various formations 

Date of desert varnish 

Diagenesis 

Color in rocks due to cementation 

Type Sections Identifying a type section for the Navajo Sandstone in the park 
 ZION Geologic Resource Evaluation Report 17

Geologic Features and Processes 

This section provides descriptions of the most prominent and distinctive geologic features 

and processes in Zion National Park. 

Biek et al. (2000) identified 24 outstanding geologic 

features in Zion. These features are summarized below 

and located on their map, reproduced here as Figure 7. 

1. The Springdale Landslide 

Triggered on September 2, 1992, by a magnitude 5.8 

earthquake, this old landslide has probably moved many 

times in the past. In 1992, 14 million cubic meters (18 

million yd3) of mostly Moenave Formation slid on the 

weak claystone of the Petrified Forest member of the 

Chinle Formation (Biek et al. 2000). Three homes and 

two water tanks were destroyed, utility lines were 

disrupted, and Utah Highway 9 was closed. 

2. The Watchman Overlook 

Millions of years of geologic history are captured in the 

bedrock units in this view of Zion Canyon. The resistant 

bench of Shinarump Conglomerate at the mouth of the 

canyon can be followed vertically upward to the gray 

limestones of the Carmel Formation high above the 

Navajo Sandstone. Landslides, joints, pediments, debris 

flows, and river terraces that help define the erosional 

history of Zion Canyon can also be seen from this 

overlook. 

3. Zion-Mt. Carmel Highway Tunnel 

This tunnel, completed in 1930, was the first milliondollar highway constructed in the U.S. The 1.8 km- long 

(1.1 mi) tunnel was blasted through the lower 80 m (260 

ft) of the Navajo Sandstone. 

4. Joints along Zion-Mt. Carmel Highway 

Weathering and erosion processes aggressively attack the 

sandstone faces exposed in near- vertical fractures, or 

joints, in the Navajo Sandstone and create the 

spectacular landscape of Zion. The orientation and 

alignment of side canyons in the eastern part of the park 

are controlled by the prominent set of north- northwesttrending joints. Excellent examples of these joints can be 

seen along the Zion- Mt. Carmel Highway. 

5. Checkerboard Mesa 

Checkerboard Mesa is an example of two weathering 

processes, one controlled by stratigraphy and one by 

climate. The “checkerboard” results from the roughly 

perpendicular sets of grooves in the Navajo Sandstone. 

The nearly horizontal grooves follow layers of coarse 

sand that coincide with eolian bedding sets whereas the 

vertical grooves have been interpreted to be the result of 

local expansion and contraction of the rock surface due 

to changes in temperature and moisture (Biek et al. 

2000). 

6. Sand Bench Landslide 

About 7,000 years ago, the relatively thin wall between 

two closely spaced joints in the Navajo Sandstone 

collapsed. The resulting Sand Bench landslide blocked 

Zion Canyon just east of The Sentinel, creating Sentinel 

Lake. For thousands of years, the Virgin River has been 

eroding the eastern part of Sand Bench landslide. The 

result is the river has steepened the landslide creating 

unstable slopes with the potential for further landslides. 

Recent landslides in 1923, 1941, and 1995 have temporarily 

dammed the Virgin River. Prior to the initial Sand Bench 

landslide, the Virgin River flowed 21 m (70 ft) lower in 

elevation than it does today. 

7. Sentinel Lake 

Stretching from the Court of the Patriarchs on the south 

upstream to the Temple of Sinawava, Sentinel Lake was 

61 m (200 ft) deep in its early stages. Horizontal lake 

sediments that can be seen along the Emerald Pools Trail 

and the Sand Bench Trail indicate that the lake was 

probably full of water all year round. 

8. Hanging Valleys 

During and after rainstorms, waterfalls cascade from the 

mouths of hanging valleys that rim the main canyons in 

Zion. These scalloped tributary valleys are alluvial 

hanging valleys. Large rivers, such as the North and East 

Forks of the Virgin River, have more erosive energy than 

the small, typically ephemeral, tributary streams that feed 

them. The larger rivers cut their canyons faster than 

streams in the side valleys. Eventually, these tributary 

valleys are left “hanging” above the floor of the main 

canyon. 

9. Weeping Rock 

The effects of groundwater movement along a contact 

between the permeable Navajo Sandstone and relatively 

impermeable Kayenta Formation are displayed at 

Weeping Rock, a picturesque alcove near the base of the 

Navajo Sandstone, below the mouth of Echo Canyon. 

Downward infiltration of groundwater directly beneath 

Echo Canyon is impeded by the Kayenta Formation. 

Flow is therefore redirected laterally toward the cliff face 

and ultimately, groundwater seeps out of the rock. The 

exact path the water follows, and where it discharges, is 

strongly influenced by joints in the sandstone. A lush 

hanging garden on the ceiling of the alcove enjoys yearround moisture due to the seeping groundwater. Because 

the water is alkaline, tufa (calcium carbonate) structures 

form on the surface of Weeping Rock. 
 NPS Geologic Resources Division 18 

10. The Narrows of Zion Canyon 

Beyond the north end of Zion Canyon Scenic Drive, the 

North Fork of the Virgin River flows for about 16 km (10 

mi) through a spectacular gorge cut into Navajo 

Sandstone. The gorge narrows to a 300- m (1,000- ft) slot 

canyon at The Narrows where the minimum width of the 

canyon floor is about 5 m (16 ft). 

11. Crater Hill Flow and Cinder Cone 

Marking the vent of one of the more voluminous 

volcanic flows in southwestern Utah, the Crater Hill 

cinder cone is the largest cinder cone in the park. 

Flowing southward into Coalpits and Scoggins Washes, 

basalt from the Crater Hill flow accumulated to a depth 

of over 122 m (400 ft) in the ancestral Virgin River valley. 

Volcanic features such as pressure ridges, which form 

concentric rings and large rafted blocks of basalt are 

“frozen” in the upper surfaces of the flow. Lake Grafton 

formed when the flow blocked the Virgin River and 

Coalpits Lake formed when it blocked Coalpits and 

Scoggins Washes. 

12. Coalpits Wash 

Several episodes of recent geologic history and fluvial 

geomorphology can be seen along Coalpits Wash. In the 

lower part of Coalpits Wash, basalt plugged the channel 

of the Virgin River exposing post- basalt gravels, a major 

debris flow plug, and several young terraces cut by the 

rapidly adjusting stream. Near the head of the basalt 

flow, in the upper part of Coalpits Wash, huge chaotic 

basalt boulders stand as evidence of undercutting and 

collapse of the flow into the newly formed wash. 

13. Trail Canyon Lake 

The Pleistocene- age Grapevine Wash basalt flow and a 

more recent large landslide involving the Kayenta 

Formation combined to create a dam upstream from the 

confluence of the Left Fork and Right Fork of North 

Creek. Lake sediments overlie the landslide deposits. A 

variety of fossils have been uncovered from these lake 

sediments including snails, fish vertebrae, and a bison 

thoracic vertebra. 

14. Basalt Stack at Left Fork North Creek 

Hiking a short distance east on the Grapevine Springs 

Trail reveals a spectacular view of 17 cooling units from 

the Grapevine Wash basalt flow. This flow erupted from 

a group of vents on the Lower Kolob Plateau at and near 

Spendlove and Firepit Knolls. Lava flowed southward 

around sandstone knobs and eventually cascaded into 

North Creek. The basalt plug is at least 137 m (450 ft) 

thick and radiometric ages taken from the top and 

bottom of the flow indicate that all of the flow was 

emplaced about 270,000 years ago. The entire stack, 

therefore, is the result of one or more closely spaced 

eruptions. Accumulation of basalt of this volume in a 

relatively short period of time is unusual for volcanic 

deposits on the Colorado Plateau. 

15. Dinosaur Tracks at Left Fork North Creek 

About 0.8 km (0.5 mi) up Left Fork on the Subway hiking 

trail lies a large boulder of Kayenta Formation sandstone 

covered with tracks from a large bipedal tridactyl (threetoed dinosaur). 

16. Subway 

The Subway is another classic example of differential 

erosion and the influence of joints on the development 

of the canyons in Zion. Located on the Left Fork of 

North Creek, this narrow canyon is wide and rounded at 

the bottom and narrow and steep- walled at the top 

because the lower transitional strata of the Navajo 

Sandstone are less resistant to erosion than the upper 

strata of the Navajo. The stream in the canyon flows 

along a series of joints during periods of low flow, thus 

illustrating the influence of joints on canyon 

development. 

17. Firepit and Spendlove Knolls 

The Firepit and Spendlove Knolls are two nearly 

perfectly conical cinder cones located near the Kolob 

Road in the west- central part of the park. They mark 

two of the vents associated with the Grapevine Wash 

basalt flows. Other, small cones are exposed to the south 

and west of these two. 

18. Old Debris-Flow Deposits 

Huge igneous boulders derived from the Pine Valley 

Mountains form much of the old debris flow deposits 

west of Little Creek Sinks and to the north on the Upper 

Kolob Plateau. The boulders are up to 7.3 m (24 ft) long, 

6.7 m (22 ft) wide, and reach an estimated 3.7 m (12 ft) 

thick. These large blocks were transported to the east 

and northeast at least 16 km (10 mi) and possibly as much 

as 26 km (16 mi). This movement would be impossible 

today because of the topographic barrier provided by the 

Hurricane fault zone. Consequently, the debris- flows 

must be older than the Hurricane fault zone. 

19. Hop Valley 

The seldom visited and enchanting Hop Valley lies in the 

Kolob Canyons portion of Zion (figure 7). Hop Valley 

“Lake” formed sometime prior to 2,640 years ago when a 

landslide dammed the mouth of the canyon. Though the 

sediment trap formed by the landslide performed much 

like a lake, the sandy nature of the sediments filling the 

valley indicates that it rarely held standing water. 

Contrast this with the sediments behind the Sand Bench 

landslide that are fine silts and clays. Hop Valley is the 

youngest of the large, landslide- dammed paleolakes in 

Zion. Sediment deposited in the lake now forms the 

valley floor that slopes gently north. These valley fill 

sediments may be as much as 107 m (350 ft) thick. 

20. Kolob Arch 

Spanning 94.5 m (310 ft) and with a window height of 101 

m (330 ft), Kolob Arch is the world’s longest natural arch 

(Biek et al. 2000). The arch is 24 m (80 ft) thick and 

formed in the middle of the massively cross- bedded 

Navajo Sandstone. The alignment of the arch suggests 
 ZION Geologic Resource Evaluation Report 19

that it is related to the north- northwest- trending joint 

system in the park, and possibly to the exfoliation joints 

that parallel the East Cougar Mountain fault. 

21. Finger Canyons of the Kolob 

Eroded into the edge of the Upper Kolob Plateau, the 

Finger Canyons are a series of west- trending canyons 

that formed along a series of west- trending joints that 

isolate large monoliths of Navajo Sandstone. Each 

canyon resembles a miniature Zion Canyon with a broad 

canyon mouth where the erodible, pre- Navajo strata are 

exposed and then taper to a slot canyon in the upper 

reaches of the canyons. 

22. Taylor Creek Thrust Fault Zone 

Thrust faults (low angle reverse faults) repeat the strata 

in the fault zone. The Taylor Creek Thrust Fault Zone is 

an excellent example of this type of structural geology. 

The Moenave strata have been repeated along one 

principal and several lesser east- dipping thrust faults on 

the east flank of the Kanarra anticline. The thrusts are 

Sevier- age back thrusts that formed under a west- east 

compressional regime during the Late Cretaceous to 

early Tertiary. 

23. Double Arch Alcove 

Formed in the massively cross- bedded Navajo 

Sandstone, the Double Arch Alcove illustrates two 

different processes of arch formation. The lower arch 

formed by spring sapping and lateral stream erosion and 

the upper arch was controlled by jointing. 

24. Hurricane Fault Zone 

The Hurricane fault zone is a major, active, steeply westdipping normal fault that stretches at least 250 km (155 

mi) from south of the Grand Canyon northward to 

Cedar City. Along the southern boundary of the park, 

tectonic displacement is about 1,098 m (3,600 ft). Zion 

rests on the eastern block and as this block was uplifted, 

the erosive power of streams draining the Kolob Terrace 

increased to help form the present landscape. 
 NPS Geologic Resources Division 20 

Figure 7. Locations of selected geologic sites in Zion. Image is imported from Biek et al. (2000). 
 ZION Geologic Resource Evaluation Report 21

Map Unit Properties 

This section provides a description for and identifies many characteristics of the map 

units that appear on the digital geologic map of Zion National Park. The table is highly 

generalized and is provided for informational purposes only. Ground disturbing 

activities should not be permitted or denied on the basis of information contained in this 

table. More detailed unit descriptions can be found in the help files that accompany the 

digital geologic map or by contacting the NPS Geologic Resources Division. 

The following Map Unit Properties Table and 

accompanying text identifies properties of individual 

map units that might impact the management of a 

specific resource. The table is tied to the digital geologic 

map and the stratigraphic column. Additional 

information may be gleaned from the cited references. 

Erosion Potential 

In general, erosion potential is highest in formations that 

have abundant siltstone and shale or are unconsolidated. 

Erosion of less resistant bedrock or unconsolidated 

sediment tends to steepen slopes and create unstable 

banks along rivers especially in a semi- arid environment 

such as in Zion. Erosion of a sparsely vegetated 

landscape is particularly intense following brief summer 

thunderstorms. 

Erosion potential in sandstone depends on the porosity 

and permeability of the sandstone and the natural 

cement that binds the grains together. Calcite cement 

will dissolve more readily in meteoric water than silica or 

iron cement. Friable sandstones are those in which the 

grains of quartz are not firmly cemented together. 

Erosion of friable sandstones form the rounded knobs 

and temples of Zion. Fractures in sandstones also tend to 

promote rapid erosion and tend to create features such 

as spires and needles. 

The Navajo Sandstone is a relatively friable sandstone 

containing abundant joints and thus, has a high erosion 

potential along fractures and joints. Many of the 

sandstones in Zion are underlain by shale or siltstone 

and are prone to undercutting which may lead to 

landslides and rockfalls. 

Aquifer Yields 

Most deliverable water in the Zion area is found in the 

cross- bedded Navajo Sandstone, Quaternary basalts, 

and unconsolidated alluvial deposits. Other aquifers have 

limited value because they either lack porosity and 

permeability or they are limited in lateral and vertical 

extent. 

Groundwater (GW) Quality 

Most of the springs in the Zion region yield water that is 

relatively low in mineral content. Generally, the longer 

groundwater is in contact with surrounding rock, the 

higher its mineral content will be. Springs that feed Oil 

Seeps Wash and Alkali Wash are also gypsiferous and 

may even taste of oil (Gregory 1950). Otherwise, 

groundwater is generally fresh while some is fresh to 

slightly saline. 

Groundwater Contamination 

Naturally occurring gypsum is the primary contaminant 

to groundwater and is found in the Petrified Forest 

member of the Chinle Formation and the Shinabkaib 

member of the Moenkopi Formation. Blebs of oil in the 

cherty conglomerate of the basal Rock Canyon 

Conglomerate member of the Moenkopi Formation may 

also impact groundwater. 

Landslide Potential 

Landslides and their subsequent erosion are the primary 

processes in canyon development at Zion and 

throughout the Colorado Plateau. These processes also 

pose potential hazards in the park. As previously 

mentioned, the soft Kayenta Formation is easily eroded 

from beneath the Navajo Sandstone. When the Navajo is 

undercut, slabs of sandstone collapse and cascade 

downslope on the weak, underlying shale beds. Fractures 

in the Navajo help facilitate this movement. Active 

landslides and old landslide deposits are common 

features throughout Zion and have a history of damming 

rivers and creating lakes. 

If located on steep slopes, unconsolidated Quaternary 

deposits have a high probably of movement especially 

during and after heavy rainfall. If the toe of these old 

landslide deposits is disturbed, by road- building for 

example, the landslide will reactivate and flow to another 

position of relative stability. The velocity of the flow 

depends on several factors such as the size of the material 

to be moved, the amount of water, the degree of slope, 

and vegetation. 

Paleontology Resources 

A detailed description of the paleontology and 

biostratigraphy of Zion National Park is beyond the 

scope of this report. The Map Unit Properties Table 

summarizes data from Santucci (2000), but a more 

comprehensive list of fossils discovered by 1950 may be 

found in Gregory (1950) 

The UGS established the following sensitivity classes for 

each strata in the park representing the presence of fossil 

resources and their vulnerability to human and natural 
 NPS Geologic Resources Division 22 

degradation. These sensitivity classes are referenced in 

the Map Unit Properties Table. 

0) Fossils absent – Formations with rock types, such as 

igneous or metamorphic rocks, that are very unlikely 

to contain fossils of any kind. 

1) Fossils rare – Formations that contain fossils only in 

rare instances such that intensive survey is unlikely 

to uncover noteworthy occurrences of fossils. 

Additionally, significant sites are known from 

Quaternary alluvium, but these sites are placed in 

this category because of the vast aerial extent of 

these surficial deposits and the low probability of 

encountering fossils at any particular location. 

2) Fossils present – Formations known to contain 

fossils, but these fossils are unlikely to be of unique 

scientific importance. For example, formations with 

abundant marine invertebrate fossils in which 

disturbance of small areas are unlikely to impact 

scientifically significant fossils. 

3) Significant sites known – Formations from which 

scientifically important fossil sites are known, but 

many areas of the formation will not contain 

significant fossil resources because of either the 

large aerial extent of the formation or rarity of these 

sites. 

4) Very sensitive – Formations known to contain 

abundant and significant vertebrate, invertebrate, 

and/or plant fossils in which a field survey is likely to 

result in the discovery of scientifically significant 

fossils. 

Extremely sensitive – Formations that can be considered 

“world- famous” because of the scientifically important 

fossils they contain. Formations in which unique and 

scientifically important fossils are very likely to be 

discovered during field survey and in which there is a 

good possibility that any disturbance will impact critical 

fossil resources. 

Cultural Resources 

Cultural resources may be expected in caves carved into 

the less resistant shales and siltstones beneath sandstone 

cliffs. Primary contacts where caves occur are at the 

Dakota Sandstone- Carmel Formation, Navajo 

Sandstone- Kayenta Formation, and Shinarump 

Conglomerate member of the Chinle Formation- upper 

red member of the Moenkopi Formation. 

Two types of caves have been etched by erosion: flatroofed structures at the base of flat- lying, regularly 

bedded, and resistant sandstones; and arched roof 

structures at the base of massive cross- bedded friable 

sandstones. Flat- roofed caves are found in the 

Moenkopi shales beneath flat- lying Shinarump 

conglomerate and in the shales beneath Cretaceous 

sandstones. Caves with arched roofs and generally flat 

floors are found in the Navajo. 

Karst Potential 

The sole formation with significant karst potential is the 

Kaibab Limestone. Karst features are common in this 

formation. 




 ZION Geologic Resource Evaluation Report 27

Geologic History 

This section highlights the map units (i.e., rocks and unconsolidated deposits) that occur 

in Zion National Park and puts them in a geologic context in terms of the environment in 

which they were deposited and the timing of geologic events that created the present 

landscape. 

This section summarizes the tectonic and depositional 

history found in Zion Natural Park. The tectonic history 

includes two major orogenic (mountain- building) 

events: one that occurred in the Mesozoic and one that 

began in the Mesozoic and ended in the Cenozoic with 

uplift of the Colorado Plateau. The depositional history 

includes a wide variety of depositional environments. 

Tectonic History 

Folds and Faults 

Folds and faults are not abundant in Zion; however, fault 

locations are important because faults are zones of 

weakness where earthquakes and mass- movements tend 

to reoccur. The Hurricane fault, created by Tertiary- age 

(Miocene) Basin- and- Range faulting, coincides with 

part of the older Sevier thrust fault. This coincidence 

suggests that the Sevier thrust fault created a zone of 

weakness that was reactivated by the Hurricane fault. 

The folds and thrust faults in Zion are primarily 

associated with two Mesozoic to Tertiary orogenic 

events: the Sevier Orogeny and the Laramide Orogeny. 

Both orogenies are the result of lithospheric plate 

collisions and subsequent subduction along the western 

margin of North America. Compressive forces during the 

Sevier Orogeny initiated thrust faulting and mountain 

building to the west during the Cretaceous. The Rocky 

Mountains were built during the Laramide Orogeny that 

extended from Late Cretaceous to Eocene. Figure 8 lists 

some of the important North American tectonic events 

and life forms that occurred throughout geologic time. 

Extending for nearly 64 km (40 mi) from near 

Toquerville to near Cedar City, the Kanarra anticline has 

its east limb exposed within Zion (Appendix A). Parts of 

the crest of the fold are also exposed at the mouths of 

Taylor Creek and Camp Creek. Strata on the east limb 

dip from 20 degrees to 35 degrees east (Biek et al. 2000). 

The dip of the beds flattens abruptly and is nearly 

horizontal under the great cliffs of Navajo Sandstone. 

The Hurricane fault zone has sheared off the western 

limb of the fold as well as parts of the crest and eastern 

limb along a line roughly parallel with the fold axis. 

In the Kolob Canyons area, the Taylor Creek thrust fault 

zone, which has pushed older strata on top of younger, 

replicates Jurassic strata on the east limb of the Kanarra 

anticline (Biek et al. 2000). Taylor Creek thrust faults are 

back thrusts generated by the regional west to east 

compression during the Sevier Orogeny. The back 

thrusts are subparallel to bedding with fault planes 

dipping to the east (Appendix A) (Hamilton 1987; Biek et 

al. 2000). In Zion repetition of the resistant, cliffforming Springdale Sandstone member of the Moenave 

Formation best illustrates the Taylor Creek fault zone. 

The Kayenta, Chinle, Moenkopi, and Kaibab strata are 

also displaced by smaller back thrusts associated with the 

Taylor Creek fault zone. The strata were displaced about 

610 m (2,000 ft) vertically and about 762 m (2,500 ft) 

horizontally. 

Cenozoic- age normal faulting has further disrupted the 

sedimentary rocks at Zion. While most of the Colorado 

Plateau was not greatly affected by Basin- and- Range 

normal faulting, extensional forces broke the western 

margin of the Colorado Plateau into a series of large 

blocks bounded by the north- south trending Hurricane, 

Sevier, Paunsaugunt, and other faults (figure 4) (Gregory 

1950; Biek et al. 2000). These large fault systems that 

parallel the western margin of the plateau demonstrate 

that Zion, CEBR, and BRCA are in a transition zone 

between the Colorado Plateau Province and the Basin 

and Range Province. Zion lies on an intermediate fault 

block bounded by the Hurricane fault zone to the west 

and the Sevier fault zone to the east. 

Faults of lesser linear extent are also present in Zion 

(Appendix A). A graben (fault bound valley) is formed by 

the offset along the East and West Cougar Mountain 

faults located in the southwest part of Zion. These faults 

are parallel, northwest- trending, steeply dipping normal 

faults probably related to Basin- and- Range extension 

although the timing of the faulting is poorly defined. The 

faults do not offset the 250,000 year- old Grapevine 

Wash basalt flows and the youngest rock displaced by 

the fault is Jurassic (Biek et al. 2000). 

Another northwest- trending normal fault is the Wildcat 

Canyon fault that parallels the Cougar Mountain faults 

(Appendix A). Temple Cap and Carmel strata in Wildcat 

Canyon have been displaced about 55 m (180 ft) (Biek et 

al. 2000). Biek et al. (2000) in their text and Hamilton 

(1987) on his map interpret the movement along the fault 

to be down- to- the- east, but Biek et al. (2000) have the 

offset drawn as down- to- the- west. Determining the 

correct orientation of this fault may be important in 

order to predict direction of movement in the future. 

The 1.0 million year old Lava Point flow to the north is 

not offset by the Wildcat Canyon fault. This fault is 
 NPS Geologic Resources Division 28 

probably contemporaneous with the East and West 

Cougar Mountain faults. 

The Bear Trap Canyon fault, a northeast- trending, highangle normal fault, with down- to- the- west movement, 

and more than 274 m (900 ft) of displacement (Hamilton 

1992; Biek et al. 2000) merges with the East Cougar 

Mountain fault (Appendix A). 

Minor folds of limited extent have been mapped in the 

Kolob area. One fold that is about 151- 172 m (495- 564 ft) 

long has the Jurassic Kayenta at the surface. Another fold 

72 m (236 ft) long is located in Jurassic Moenave 

Formation through Quaternary deposits. A third fold 

also affects Moenave Formation strata and extends for 

about 106- 116 m (348- 380 ft) on the surface. 

Joints 

In contrast to the limited number of folds and faults, 

joints are ubiquitous throughout Zion. The joints are 

exceptionally well developed, and are instrumental in 

orienting today’s canyon network by channeling runoff 

(Biek et al. 2000). Joints are simply cracks in the bedrock 

without any significant offset. The most prominent joints 

in Zion trend north- northwest and are found in the 

Navajo Sandstone. These joints are nearly vertical and 

are spaced widely apart with some uniformity. Crushed 

or sheared zones associated with the joints indicate two 

diametrically opposite types of crustal stresses: one set 

related to compression and one set related to tension 

(Biek et al. 2000). Rogers (2002) suggests that joints were 

initiated with tension related to Basin- and- Range 

extension, but that the joints did not propagate until 

surface erosion began cutting into the rock and 

preferentially following and facilitation joint 

development. The result is near parallel, regularly 

spaced, joint- controlled canyons. 

Some joints near rock surfaces formed because of 

erosion. These joints are termed exfoliation joints and 

form roughly parallel to the rock face as overlying 

bedrock and sediments are eroded. Other joints, such as 

those at Checkerboard Mesa, are thought to form due to 

local expansion and contraction near the surface of the 

rock as it is subjected to constant, persistent temperature 

and moisture changes. 

Depositional History 

The strata of Zion represent layer upon layer of 

overlapping and interfingering marine and non- marine 

depositional environments (figure 9). 

Permian Period 

About 275 million years ago the Permian equator passed 

through what is now eastern Utah and Wyoming along 

the western margin of Pangaea, the supercontinent 

forming as the globe’s landmasses sutured together (Biek 

et al. 2000; Morris et al. 2000). A dry, high atmospheric 

pressure climatic belt prevailed in this western part of 

Pangaea and resulted in restricted marine evaporitic 

conditions over much of the cratonic shelf seaway 

(Peterson 1980). Warm, shallow seas and sabkhas (broad, 

very flat surfaces near sea level) covered the area. Farther 

to the west, a complex island arc assemblage formed 

above a subduction zone as lithospheric plates collided 

(Silberling and Roberts 1962). To the east, in western 

Colorado, the majestic, jagged peaks (similar to today’s 

Himalayas) of the Uncompahgre Mountains bordered 

the Utah lowland. 

The Toroweap Formation contains evidence of four 

environments of deposition created by the advance and 

retreat of the shoreline across northern Arizona and 

southwestern Utah (Rawson et al. 1980). From west to 

east, these four environments include an open marine 

environment, restricted marine, sabkha, and eolian dune 

environments. As sea level continued to rise during the 

initial Toroweap transgression, normal marine organisms 

such as brachiopods, crinoids, corals, and bryozoans 

entered the Zion area, and their shell material is 

incorporated in the Toroweap limestones. The 

fossiliferous limestone, dolomite, and limy sandstone 

environments record three transgressive pulses (Rawson 

et al. 1980). 

Following the last transgression, the sea withdrew to 

Nevada and coastal sabkha environments spread over 

Zion. Eolian dune fields formed east of the sabkhas. One 

last Toroweap transgressive pulse swept marine 

environments back into the area from the west. 

The Kaibab Limestone records the last in a long series of 

shallow seas that transgressed over the Zion region 

throughout the Paleozoic Era. Oolites, disarticulated and 

broken marine fossil fragments, dolomite, siliceous 

sponge spicules, and gypsum, all found in the Kaibab, 

formed under shallow, near- shore, warm and arid 

climatic conditions (Hamilton 1992). Spherical, modern 

oolites, similar to those found in the Kaibab Limestone, 

are currently being formed in warm, shallow marine 

water where they slowly accrete carbonate mud to their 

round surfaces as waves gently roll them back and forth 

over the sea bottom. 

The interfingering of the Kaibab with the White Rim 

Sandstone in the Capital Reef National Park area to the 

east suggests that the marine facies of the Kaibab 

migrated eastward in response to a relative sea- level rise, 

or transgression (Dubiel et al. 1996). The sea moved back 

and forth across Utah, but by the Middle Permian, the 

sea had withdrawn and the Kaibab Limestone was 

exposed to subaerial erosion (Morris et al. 2000). 

Dissolution of the Kaibab created karst topography and 

channels reaching 30 m (100 ft) in depth cut into the 

limestone surface (Morris et al. 2000). 

The close of the Permian brought the third, and most 

severe, mass extinction of geologic time. Although not as 

famous as the extinction event that exterminated the 

Dinosaurs at the end of the Mesozoic, the Permian 

extinction was much more extensive. 
 ZION Geologic Resource Evaluation Report 29

Almost 96% of all species were extinct by the end of the 

Permian (Raup 1991). The most recent hypothesis 

regarding the Permian event suggests that a comet, about 

6- 13 km (4- 8 mi) in diameter, slammed into Earth 

(Becker et al. 2001), triggering vast volcanic eruptions 

that spread lava over an area two- thirds the size of the 

United States. 

Triassic Period 

During the Triassic (250 to 206 million years ago), the 

supercontinent Pangaea reached its greatest size. All the 

continents had come together to form a single landmass 

that was located symmetrically about the equator (Dubiel 

1994). To the west, explosive volcanoes arose from the 

sea and formed a north- south trending arc of islands 

along the border of what is now California and Nevada 

(Christiansen et al. 1994; Dubiel 1994; Lawton 1994). 

Shallow, marine water stretched from eastern Utah to 

eastern Nevada over a beveled continental shelf. As the 

sea withdrew, fluvial, mudflat, sabkha, and shallow 

marine environments developed (Lower Triassic, 

Moenkopi Formation) (Stewart et al. 1972A; Christiansen 

et al. 1994; Doelling 2000; Huntoon et al. 2000). The Red 

Canyon Conglomerate, the basal member of the 

Moenkopi, fills broad east- flowing paleochannels 

carved into the Kaibab Limestone (Biek et al. 2000). 

Some of these channels are up to several tens of feet deep 

and may reach 61 m (200 ft) deep in the St. George area. 

A thin poorly developed soil or regolith formed over the 

paleotopographic high areas between the channels (Biek 

et al. 2000). 

The fossilized plants and animals in the Moenkopi are 

evidence of a climate shift to a warm tropical setting that 

may have experienced monsoonal, wet- dry conditions 

(Stewart et al. 1972A; Dubiel 1994; Huntoon et al. 2000; 

Morris et al. 2000). 

At Zion, the limestones and fossils of the Timpoweap, 

Virgin Limestone, and Shnabkaib members of the 

Moenkopi Formation document transgressive episodes. 

Unlike the Timpoweap and Virgin Limestone members, 

the Shnabkaib contains abundant gypsum and 

interbedded mudstone resulting from deposition in a 

restricted marine environment with complex watertable fluctuations (Biek et al. 2000). 

Regressive, red- bed layers separate the transgressive 

strata. Ripple marks, mud cracks, and thinly laminated 

bedding suggest that these intervening red shale and 

siltstone units were deposited in tidal flat and coastalplain environments (Stewart et al. 1972A; Hamilton 1992; 

Biek et al. 2000). 

The Early Triassic is separated from the Late Triassic by 

a regional unconformity (figure 5). This unconformity 

marks a change from the shallow marine environments 

of the Lower Triassic Moenkopi Formation to mostly 

continental sedimentation in the Upper Triassic Chinle 

Formation. The Middle Triassic remains a mystery. No 

rocks that span this time (from 242- 227 Ma) have been 

preserved in Utah. By the Late Triassic, Utah was part of 

a large interior basin drained by north- and northwestflowing rivers (Biek et al. 2000). Braided streams 

deposited coarse sediments (Shinarump Conglomerate 

member) in paleovalleys eroded into the underlying 

Moenkopi Formation (Dubiel 1994; Biek et al. 2000). 

High- sinuosity stream, flood plain, and lake sediments 

(Petrified Forest member) overly the braided stream 

deposits in the Zion region (Stewart et al. 1972B; Dubiel 

1994; Biek et al. 2000). Aquatic crocodile- like 

Phytosaurs, lungfish, and lacustrine bivalves inhabited a 

Utah that looked vastly different in the Upper Triassic 

than it does today. Rather than a semi- arid desert 

environment, the Zion area was a coastal lowland 

supporting amphibians, reptiles, freshwater clams, snails, 

ostracodes, and fish. The moist climate supported 

conifer trees, cycads, ferns, and horsetails (Stewart et al. 

1972B; Dubiel 1994; Biek et al. 2000). Periodically, 

volcanic ash from the volcanic arc off the continental 

margin to the west drifted into the area and was 

subsequently altered to bentonitic clay that today is 

notoriously susceptible to landslides and for causing 

foundation problems in southwest Utah. 

About ten million years is missing between the Chinle 

Formation and the Early Jurassic Moenave Formation. 

This basal Jurassic unconformity extends from central 

and western Wyoming, through Utah and the Four 

Corners area, and into northwest New Mexico and the 

San Juan Basin (Pipiringos and O’Sullivan 1978; Peterson 

1994). 

Jurassic Period 

Throughout the Jurassic’s 100 million years, periodic 

incursions from the north brought shallow seas flooding 

into Wyoming, Montana, and a northeast- southwest 

trending trough on the Utah/Idaho border. The Jurassic 

western margin of North America was associated with an 

Andean- type margin where the eastward subduction of 

the seafloor gave rise to volcanism similar to that found 

in today’s Andes of South America. Volcanoes formed an 

arcuate north- south chain of mountains off the coast of 

western Pangaea in what is now central Nevada. To the 

south, the landmass that would become South America 

was splitting away from the Texas coast just as Africa and 

Great Britain were rifting away from the present East 

Coast and opening up the Atlantic Ocean. The Ouachita 

Mountains, formed when South America collided with 

North America, remained a significant highland, and 

rivers from the highland flowed to the northwest, 

towards the Plateau. The Ancestral Rocky Mountains 

and the Monument Upwarp also remained 

topographically high during the Jurassic. 

Bordered by these highlands, the Western Interior Basin 

was a broad, shallow depression on the southwest side of 

the North American craton. The basin stretched 

northward from its southern margin in Arizona and New 

Mexico across the Canadian border. The basin was 
 NPS Geologic Resources Division 30 

asymmetric, rapidly subsiding along the west side and 

more gently dipping farther east. 

The Moenave Formation was deposited in a variety of 

river, lake, and flood- plain environments (Biek et al. 

2000). Ripple marks, cross- bedding, reddish and gray 

siltstone and shale, fossil fish scales, and bones of 

Semionotus kanabensis suggest low energy streams and 

ponded drainages (Dinosaur Canyon and Whitmore 

Point members) (Hamilton 1992). The thin, 

discontinuous lenses of intraformational conglomerate, 

fine- grained rip- up clasts (mud clasts “ripped- up” by 

currents and transported elsewhere), and fossil plant 

fragments found in the Springdale member record 

deposition in river channels (Biek et al. 2000). 

Fluvial processes continued to affect southwestern Utah 

by the deposition of the Kayenta Formation. 

Interbedded sandstone, basal conglomerates, siltstones, 

mudstones, and thin cross- beds are typical channel and 

floodplain deposits found in the Kayenta. Paleocurrent 

studies show that the Kayenta rivers flowed in a general 

westward to southwestward direction (Morris et al. 

2000). 

Mountains in Nevada and California continued to rise in 

the Early Jurassic as plate motions forced North America 

northward. Eventually, this created a rain shadow. 

Gradually, sand dune deposits reaching 240 to 340 m 

(800 to 1100 ft) overtook the fluvial systems of the 

Kayenta. These dune fields became the Navajo 

Sandstone, part of the world’s largest coastal and inland 

paleodune field (Blakey 1994; Peterson 1994; Biek et al. 

2000). The large- scale (18 m, 60 ft), high- angle, crossbeds of the Navajo attest to the presence of Sahara- like 

sand dunes during the Early Jurassic (Biek et al. 2000; 

Morris et al. 2000). 

Extensive eolian sand seas, called ergs, developed in the 

Western Interior Basin mainly because the region was 

located about 18 degrees north latitude at the beginning 

of the Jurassic and about 30- 35 degrees north latitude at 

the end of the Jurassic (Parrish and Petersen 1988; Chan 

and Archer 2000; Kocurek and Dott 1983; Peterson 1994). 

This latitude marks today’s trade wind belt where hot, 

dry air descends from the upper atmosphere and sweeps 

back to the equator in a southwesterly direction, picking 

up any moisture as it goes - the latitude of intense 

evaporation. Most modern hot deserts of the world 

occur within the trade wind belt and during the Jurassic, 

the climate of the Colorado Plateau appears to have been 

similar to the modern Western Sahara. 

In the Sahara, the world’s largest desert, only 10% of the 

surface is sand- covered. The Arabian Desert, Earth’s 

sandiest desert, is only 30 percent sand- covered. The 

Jurassic deserts that occurred across the Colorado 

Plateau for roughly 40 million years (not counting the 

time represented by erosion) contained sand dunes that 

may be the largest recorded in the rock record (Kocurek 

and Dott 1983). These ergs formed on a coastal and 

inland dune field affecting southern Montana, eastern 

Utah, westernmost Colorado, southwest Colorado, 

northeastern Arizona, and northwestern New Mexico 

(Kocurek and Dott 1983; Peterson 1994). The volume of 

sand in these systems was enormous. Ergs may have 

covered 106 km2

 (41 mi2) with as much as 1.5x105 km3 (3.6 

x104 mi3) of sand being deposited (Saleeby et al. 1992). 

Two types of cyclicity have been observed in Navajo 

sandstone. First there are layers of annual deposition 

where 1 to several meters of sand accumulates on the 

dune face during strong winds, separated by thinner 

wedges of sand deposited during light and variable 

winds. These have been interpreted as deposition during 

seasonal monsoon winds from the north (Loope et al. 

2001). Secondly, studies of cyclicity in the annual dune 

sets suggest that the region experienced contrasts of 

wetter and drier periods on a decade scale in the Early 

Jurassic (Chan and Archer 2000). 

Great, sweeping Navajo cross- beds are wonderfully 

preserved at Zion. As in modern deserts, where ground 

water reached close to the surface, oases formed. Planar 

sandstone and limestone beds found in the middle and 

upper parts of the Navajo represent oasis deposits 

formed in these active dunefields. One good example of 

fossil oasis deposits can be seen along the Canyon 

Overlook Trail (Biek et al. 2000). The top of the Navajo 

Formation and the end of the Early Jurassic is marked by 

another regional unconformity. 

As the pace of west coast collision increased in the 

Middle Jurassic (about 160 to 180 Ma) to about as fast as 

fingernails grow, the rock layers on the continental side 

of the collision, in Utah and western Colorado, 

deformed in response to the collision to the west (Sevier 

Orogeny). The sea began to encroach on the continent 

from the north. Broad tidal flats and streams carrying red 

mud (Sinawava member of the Temple Cap Formation) 

formed on the margins of a shallow sea that lay to the 

west, and flat- bedded sandstones, siltstones, and 

limestones filled depressions left in the underlying 

eroded strata (Wright et al. 1962; Hamilton 1992; Biek et 

al. 2000; Doelling 2000). Streams eroded the poorly 

cemented Navajo Sandstone, and water caused the sand 

to slump. Desert conditions returned briefly (White 

Throne member), but encroaching seas again beveled the 

coastline, forming a regional unconformity. 

Crinoid, pectin, clam, and oyster fossils of the Carmel 

Formation were deposited in a shallow inland sea (Biek 

et al. 2000). Many unique environments were created by 

the migrating Sevier thrust system and the four members 

of the Carmel Formation in southwest Utah capture 

these changing environments (figure 9). Both open 

marine (crinoids) and restricted marine (pelecypods, 

gastropods) environments are represented in the Co- op 

Creek member. Sandstone and gypsum in the Crystal 

Creek and Paria River members signal a return to desert 

conditions in a coastal setting (Biek et al. 2000; Morris et 

al. 2000). 
 ZION Geologic Resource Evaluation Report 31

Cretaceous Period 

As mountains rose in the west and the roughly northsouth trending Western Interior Basin expanded in the 

Cretaceous, the Gulf of Mexico separating North and 

South America continued to rift open in the south, and 

marine water began to advance northward into the basin. 

At the same time, marine water advanced onto the 

continent from the Arctic region. 

The seas advanced and retreated many times during the 

Cretaceous until the most extensive interior seaway ever 

recorded drowned much of western North America 

(figure 10). The Western Interior Seaway was an elongate 

basin that extended from today’s Gulf of Mexico to the 

Arctic Ocean, a distance of about 4827 km (3,000 mi) 

(Kauffman 1977). The western margin of the seaway 

coincided with the active Cretaceous Sevier orogenic belt 

with the westernmost extension of the shoreline in the 

vicinity of Cedar City, Utah. The eastern margin was part 

of the low- lying, stable platform ramp in Nebraska and 

Kansas. 

The pebble to cobble conglomerate and tan sandstone 

that compose the Cretaceous rocks exposed at the top of 

Horse Ranch Mountain include alluvial- fan and 

alluvial- plain sediments that grade laterally into coastal 

plain, marginal marine, and marine deposits (Biek et al. 

2000). For the first time in the history of the Mesozoic, 

the source area for these terrestrial clastic sediments is 

from the west, a result of the Sevier Orogeny. 

Tertiary Period 

Explosive andesitic volcanism dominated the area to the 

west of Zion during Oligocene and early Miocene time 

and probably inundated the region with hundreds of feet 

of welded tuff that has since eroded away (Biek et al. 

2000). Three of these tuff layers are preserved on top of 

Brainhead Peak. Some of these enormous cascadia- type 

volcanoes produced eruptions that exceeded the largest 

Yellowstone eruptions (Dave Sharrow, Zion National 

Park, personal communication 2005). About 21 million 

years ago the Pine Valley laccolith formed. This typical 

mushroom- shaped laccolith is one of the largest 

intrusions of this type in the world. Debris- flows carried 

boulders of this intrusion onto the Upper Kolob Plateau 

indicating that the Hurricane Cliffs could not have been 

present at the time. 

Quaternary Period 

Synthesizing geologic maps for the quadrangles that 

cover Zion, 100 Quaternary units are mapped on the 

NPS- GIS digital map. These units are summarized in 

Biek et al. (2000) who organized the surficial deposits 

into six main types of surficial sedimentary deposits 

common in the park: 

• alluvium, 

• colluvium and residuum, 

• talus, 

• eolian deposits, 

• mass- movement deposits (including landslides and 

debris flows), and 

• lacustrine or basin- fill deposits. 

Unlike the consolidated bedrock units, these surficial 

units are classified according to their interpreted mode 

of deposition, or genesis. In addition to these (but too 

small to map), are the rare tufa deposits associated with 

springs and the basalt flows and cinder cones that stand 

in stark contrast to the surrounding red- rock strata. 

The surficial deposits of Zion speak to an active recent 

history of the park. Older debris- flow deposits contain 

subrounded basalt boulders brought in from a western 

source before the Hurricane fault zone was a significant 

topographic barrier to deposition. Analyses of the basalt 

flows and cinder cones reveal an eruptive cycle that may 

have lasted less than 100 years before going extinct (Biek 

et al. 2000). The volcanic vents appear to be located 

along faults and joints, structurally weak zones in the 

rock. 

Quaternary basalt flowed down canyons and drainages 

onto valley floors, just as magma does today. Because 

basalt is more resistant to erosion than sedimentary 

rocks, however, erosion has removed the surrounding 

sedimentary rock that once stood at higher elevations so 

that the basalt now caps ridges that separate adjacent 

drainages. Thus, they form an “inverted topography” in 

which the valleys that were once flooded with basalt are 

now ridges and plateaus. 

Impounded behind landslides and lava flows, small lakes 

and ephemeral ponds filled the canyons of Zion. About 

100,000 years ago, the Crater Hill basalt flow blocked the 

Virgin River near the present- day ghost town of 

Grafton. Behind this barrier, Lake Grafton grew to 

become the largest of at least 14 lakes that have 

periodically formed in the park. 

Zion National Park is a monument to erosion and the 

impact that water has in a dry, sparsely vegetated 

landscape. Runoff from precipitation and snowmelt has 

eroded thousands of feet of strata from the Zion block in 

the Quaternary. Canyon cutting could only begin in 

earnest when the Colorado River began flowing through 

Grand Canyon and on to the sea about 4.5 million years 

ago. The Virgin River could then link with the Colorado 

and begin expanding its watershed into the Colorado 

Plateau. It does this at the expense of the Sevier River 

drainage, which has less erosive energy because it has a 

gentle gradient draining to the Great Basin about 4,000 

feet in elevation, rather than sea level. 

Normally a small, placid stream, easy to wade across, the 

Virgin River does not seem capable of eroding such an 

immense canyon as Zion. However, the Virgin River 

carries away more than 1 million tons of rock waste each 

year due its steep gradient of about 13 meters per 

kilometer (69 ft/mi) (Biek et al. 2000). Nearly all of the 

sediment transport occurs during floods because the 
 NPS Geologic Resources Division 32 

capacity of the river to move sediment increases 

exponentially as the streamflow increases. A ten- fold 

increase in flow, a common occurrence, results in a 

1,000- fold increase in sediment transport. Peak flows, 

however, are quite variable with a range from 0.6- 256 

m3

/sec (21- 9,150 cfs) near Springdale to 0.6- 638 m3/sec 

(21- 22,800 cfs) downstream near Virgin. During the 

wetter Pleistocene past, average sediment transport was 

probably even greater than it is today. 

Downcutting and canyon widening are the two 

dominant erosional processes forming the canyons at 

Zion (Biek et al. 2000). Downcutting is represented at 

The Narrows at the head of Zion Canyon where the 

North Fork of the Virgin River flows through a 

spectacular gorge cut into the Navajo Sandstone. Acting 

like a ribbon of moving sandpaper through The 

Narrows, the Virgin River has carved a 305 meter- deep 

(1,000 ft) gorge that, in places, is only 5 m (16 ft) wide at 

the bottom. 

The second dominant erosional process, canyon 

widening, makes use of the different erosional properties 

between the Kayenta Formation and the overlying 

Navajo Sandstone. The thin- bedded siltstone, 

sandstone, and shale of the Kayenta Formation are softer 

and more easily eroded than the massive sandstone of 

the Navajo. Consequently, as the Kayenta is eroded and 

slips away in landslides, the Navajo cliffs are undercut. 

Seeps and springs at the contact of the permeable Navajo 

and relatively impermeable Kayenta further undermine 

the Navajo cliffs until they collapse in rockfalls and 

landslides. Failure of the Navajo is facilitated by the 

vertical joints in the sandstone, as well. During canyon 

widening the Virgin River acts primarily as a conveyor 

that transports the material washed off the slopes 

downstream. 

Carved in the Jurassic- age Navajo Sandstone, the sheer 

walls of Zion Canyon rise 610 m (2,000 ft) from the 

canyon floor. A narrow slot in its upper reaches, the 

canyon widens below The Narrows where the North 

Fork of the Virgin River has cut a wider flood plain in the 

less resistant beds of the Jurassic Period Kayenta and 

Moenave Formations (Biek et al. 2000). 

The Virgin River has cut down about 396 m (1,300 ft) in 

about 1 million years. This rate of canyon cutting is about 

40 centimenters/1,000 years (1.3 ft/1,000 yr). This is a very 

rapid rate of downcutting, about the same rate as 

occurred in Grand Canyon during its period of most 

rapid erosion. About 1 million years ago, Zion Canyon 

was only about half as deep as it is today in the vicinity of 

Zion Lodge (Biek et al. 2000). Definitive evidence is 

sparse for determining long- term erosion rates of Zion 

Canyon, but if the assumption is made that erosion was 

fairly constant over the past 2 million years, then the 

upper half of Zion Canyon was carved between about 1 

and 2 million years ago and only the upper half of the 

Great White Throne was exposed 1 million years ago and 

The Narrows were yet to form. Downcutting and canyon 

widening continue today as the relentless process of 

erosion continues to bevel the landscape to sea level.
 ZION Geologic Resource Evaluation Report 33

Figure 8. Geologic time scale. Red lines indicate major unconformities between eras. Absolute ages shown are in millions of years. Scale is 

from the U.S.G.S. 
 NPS Geologic Resources Division 34 

Figure 9. Depositional environments represented by the strata in Zion National Park. 
 ZION Geologic Resource Evaluation Report 35

Figure 10. Location of the Cretaceous Period, Western Interior Seaway. Shaded areas indicate land above sea level. North arrow indicates 

the Cretaceous north. Modified from Rice and Shurr (1983). 
 NPS Geologic Resources Division 36 

References 

This section provides a listing of references cited in this report. A more complete geologic 

bibliography is available and can be obtained through the NPS Geologic Resources 

Division. 

Biek, R.F., Willis, G.C., Hylland, M.D., and Doelling, 

H.H., 2000, Geology of Zion National Park, Utah, in 

D.A. Sprinkel, T.C. Chidsey, Jr., and P.B. Anderson, 

eds., Geology of Utah’s Parks and Monuments: Utah 

Geological Association Publication 28, p. 107- 138. 

 

Becker, L., Poreda, R. J., Hunt, A. G., Bunch, T. E., and 

Rampino, M., 2001, Impact event at the PermianTriassic boundary: Evidence from extraterrestrial 

noble gases in fullerenes: Science, Feb. 23, p. 1530- 1533. 

Blakey, R. C., 1994, Paleogeographic and tectonic 

controls on some Lower and Middle Jurassic erg 

deposits, Colorado Plateau, in Mario V. Caputo, James 

A. Peterson, and Karen J. Franczyk, eds., Mesozoic 

Systems of the Rocky Mountain Region, USA: Rocky 

Mountain Section, SEPM (Society for Sedimentary 

Geology), Denver, CO., p. 273- 298. 

Burghardt, J., 1991, Abandoned Mine Lands evaluation of 

Epsolon Mine near Zion National Park, Utah: 

unpublished report, National Park Service Geologic 

Resources Division, Lakewood, Colorado. 

Chan, M. A. and Archer, A. W., 2000, Cyclic eolian 

stratification on the Jurassic Navajo Sandstone, Zion 

National Park: Periodicities and implications for 

paleoclimate, in D.A. Sprinkel, T.C. Chidsey, Jr., and 

P.B. Anderson, eds., Geology of Utah’s Parks and 

Monuments: Utah Geological Association Publication 

28, p. 607- 618. 

Christiansen, E. II, Kowallis, B. J., and Barton, M. D., 

1994, Temporal and spatial distribution of volcanic ash 

in Mesozoic sedimentary rocks of the Western 

Interior: an alternative record of Mesozoic 

magmatism, in M. V. Caputo, J. A. Peterson, and K. J. 

Franczyk, eds., Mesozoic Systems of the Rocky 

Mountain Region, USA: Rocky Mountain Section, 

SEPM (Society for Sedimentary Geology), Denver, 

CO., p. 73- 94. 

Clyde, C.G., 1987, Groundwater Resources of the Virgin 

River Basin: Utah Division of Natural Resources, 104 p. 

Cordova, R.M., 1978, Ground- Water Conditions in the 

Navajo Sandstone in the Central Virgin River Basin, 

Utah: Utah Department of Natural Resources, 

Technical Publication 61, 66 p. 

DeBlieux, D.D, Smith, J.A., McGuire, J.L., Kirkland, J.I., 

and Santucci, V.L., 2005, Zion National Park 

Paleontological Survey: Utah Geological Survey, Salt 

Lake City, Utah, 75 p. 

Doelling, H. H., 2000, Geology of Arches National Park, 

Grand County, Utah, in D.A. Sprinkel, T.C. Chidsey, 

Jr., and P.B. Anderson, eds., Geology of Utah’s Parks 

and Monuments: Utah Geological Association 

Publication 28, p. 11- 36. 

Driscoll, P.L., 1978, Virgin (Oil), in J.E. Fassett, ed., Oil 

and Gas Fields of the Four Corners Area: Four 

Corners Geological Society, vol II, p. 712- 716. 

Dubiel, R. F., 1994, Triassic deposystems, 

paleogeography, and paleoclimate of the Western 

Interior, in M. V. Caputo, J. A. Peterson, and K. J. 

Franczyk, eds., Mesozoic Systems of the Rocky 

Mountain Region, USA: Rocky Mountain Section, 

SEPM (Society for Sedimentary Geology), Denver, 

CO., p. 133- 168. 

Dubiel, R. F., Huntoon, J. E., Condon, S. M., Stanesco, J. 

D., 1996, Permian deposystems, paleogeography, and 

paleoclimate of the Paradox Basin and vicinity, in

M.W. Longman and M.D. Sonnenfeld, eds., Paleozoic 

Systems of the Rocky Mountain Region: Rocky 

Mountain Section, SEPM (Society for Sedimentary 

Geology), p. 427- 444. 

Eardley, A.J., and Schaack, J.W., 1991, Zion – the story 

behind the scenery: KC Publications, Las Vegas, NV., 

46 p. 

Fillmore, R., 2000, The Geology of the Parks, 

Monuments and Wildlands of Southern Utah: The 

University of Utah Press, 268 p. 

Gregory, H.E., 1950, Geology and Geography of the Zion 

Park Region Utah and Arizona: U.S.G.S. Professional 

Paper 220, 200 p. 

Hamilton, W.L., 1987, Geological Map of Zion National 

Park, Utah: Zion Natural History Association, Zion 

National Park, Springdale, Utah, scale 1: 31680. 

Hamilton, W.L., 1992, The Sculpturing of Zion: Zion 

Natural History Association, Revised 1984 edition, 

132 p. 
 ZION Geologic Resource Evaluation Report 37

Hereford, R., Jacoby, G.C., and McCord, V.A.S., 1995, 

Geomorphic History of the Virgin River in the Zion 

National Park Area, Southwest Utah: U.S.G.S. OpenFile Report 95- 515, 75 p. 

Huntoon, J. E., Stanesco, J. D., Dubiel, R. F., and Dougan, 

J., 2000, Geology of Natural Bridges National 

Monument, Utah, in D.A. Sprinkel, T.C. Chidsey, Jr., 

and P.B. Anderson, eds., Geology of Utah’s Parks and 

Monuments: Utah Geological Association Publication 

28, p. 233- 250. 

Kauffman, E. G., 1977, Geological and biological 

overview: Western Interior Cretaceous Basin: 

Mountain Geologist, v. 14, p. 75- 99. 

Kiver, E.P. and Harris, D.V., 1999, Geology of U.S. 

Parklands: John Wiley & Sons, Inc., 5th edition, 

p. 455- 466. 

Kocurek, G. and Dott, R. H. Jr., 1983, Jurassic 

paleogeography and paleoclimate of the central and 

southern Rocky Mountain region, in M. W. Reynolds 

and E. D. Dolly, eds., Mesozoic Paleogeography of the 

West- Central United States: Rocky Mountain Section, 

SEPM (Society for Sedimentary Geology), Denver, 

CO., p. 101- 118. 

Lawton, T. F., 1994, Tectonic setting of Mesozoic 

sedimentary basins, Rocky Mountain region, United 

States, in Mario V. Caputo, James A. Peterson, and 

Karen J. Franczyk, eds., Mesozoic Systems of the 

Rocky Mountain Region, USA: Rocky Mountain 

Section, SEPM (Society for Sedimentary Geology), 

Denver, CO., p. 1- 26. 

Loope, D.B., Rowe, C.M., and Joeckel, R.M., 2001, 

Annual monsoon rains recorded by Jurassic dunes: 

Letter to Nature, Nature, v. 412, p. 64- 66. 

Morris, T., H., Manning, V. W., and Ritter, S. M., 2000, 

Geology of Capitol Reef National Park, Utah: in D.A. 

Sprinkel, T.C. Chidsey, Jr., and P.B. Anderson, eds., 

Geology of Utah’s Parks and Monuments: Utah 

Geological Association Publication 28, p. 85- 106. 

Nelson, S.T., and Tingey, D.G., 1997, Time- transgressive 

and extension- related basaltic volcanism in southwest 

Utah and vicinity: Geological Society of America 

Bulletin 109, p. 1249- 1265. 

Parrish, J.T., and Peterson, F., 1988, Wind directions 

predicted from global circulation models and wind 

directions determined from eolian sandstones of the 

western United States – a comparison: Sedimentary 

Geology, v. 56, p. 261- 282. 

Peterson, F., 1994, Sand dunes, sabkhas, stream, and 

shallow seas: Jurassic paleogeography in the southern 

part of the Western Interior Basin, in M. V. Caputo, J. 

A. Peterson, and K. J. Franczyk, eds., Mesozoic 

Systems of the Rocky Mountain Region, USA: Rocky 

Mountain Section, SEPM (Society for Sedimentary 

Geology), Denver, CO., p. 233- 272. 

Peterson, J. A., 1980, Permian paleogeography and 

sedimentary provinces, west central United States, in

Thomas D. Fouch and Esther R. Magathan, eds., 

Paleozoic Paleogeography of the West- Central United 

States: Rocky Mountain Section, SEPM (Society for 

Sedimentary Geology), p. 271- 292. 

Pipiringos, G.N., and O’Sullivan, R.B., 1978, Principal 

unconformities in Triassic and Jurassic rocks, western 

interior United States – a preliminary survey: U.S.G.S. 

Professional Paper 1035- A, 29 p. 

Rawson, R.R. and Turner- Peterson, C.E., 1980, 

Paleogeography of northern Arizona during the 

deposition of the Permian Toroweap Formation, in

T.D. Fouch and E.R. Magathan, eds., Paleozoic 

Paleogeography of the West- Central United States: 

Rocky Mountain Section of SEPM, p. 341- 352. 

Raup, D. M., 1991, Extinction: Bad Genes or Bad Luck?: 

W.W. Norton and Company, New York, 210 p. 

Rice, D. D. and Shurr, G. W., 1983, Patterns of 

sedimentation and paleogeography across the Western 

Interior Seaway during time of deposition of Upper 

Cretaceous Eagle Sandstone and equivalent rocks, 

northern Great Plains, in M. W. Reynolds and E. D. 

Dolly, eds., Mesozoic Paleogeography of the WestCentral United States: Rocky Mountain Section, 

SEPM (Society for Sedimentary Geology), p. 337- 358. 

Rogers, C.M, 2002, Kinematic implications and dynamic 

analysis of regularly spaced joint zones of the Navajo 

Sandstone, Zion National Park, Utah: Master’s Thesis, 

Pennsylvanian State University, 123 p. 

Saleeby, J.R., and Busby- Spera, C., 1992, Early Mesozoic 

tectonic evolution of the western U.S. Cordillera, in 

B.C. Burchfiel, P.W., Lipman, and M.L., Zoback, eds., 

The Cordilleran Orogen: Conterminous U.S.: 

Geological Society of America, the Geology of North 

America, V. G- 3, p. 107- 168. 

Santucci, V. L., 2000, A survey of paleontologic resources 

from the National Parks and Monuments in Utah: in 

D.A. Sprinkel, T.C. Chidsey, Jr., and P.B. Anderson, 

eds., Geology of Utah’s Parks and Monuments: Utah 

Geological Association Publication 28, p.535- 556. 

Silberling, N. J. and Roberts, R. J., 1962, Pre- Tertiary 

stratigraphy and structure of northwestern Nevada: 

GSA Special Paper 72, 58 p. 
 NPS Geologic Resources Division 38 

Stegner, Wallace, 1954, Beyond the Hundredth Meridian: 

Penguin Books, New York, 438 p. 

Stewart, J.H., Poole, F.G., and Wilson, R. F., 1972A, 

Stratigraphy and origin of the Triassic Moenkopi 

formation and related strata in the Colorado Plateau 

region with a section on sedimentary petrology by R.A. 

Cadigan: USGS Prof Paper 691, 195 p. 

Stewart, J.H., Poole, F.G., and Wilson, R. F., 1972B, 

Stratigraphy and origin of the Chinle Formation and 

related Upper Triassic strata in the Colorado Plateau 

region with a section on sedimentary petrology by R.A. 

Cadigan and on conglomerate studies by W. 

Thordarson, H.F. Albee, and J.H. Stewart: USGS Prof 

Paper 690, 336 p. 

Wright, J.C., Shawe, D.R., and Lohman, S.W., 1962, 

Definition of members of Jurassic Entrada Sandstone 

in east- central Utah and west- central Colorado: 

American Association of Petroleum Geologists 

Bulletin, v. 46, no. 11, p. 2057- 2070. 
 ZION Geologic Resource Evaluation Report 39

Appendix A: Geologic Map Graphic 

The following page provides a preview or “snapshot” of the geologic map for Zion 

National Park. For a poster size PDF of this map or for digital geologic map data, please 

see the included CD or visit the GRE publications webpage: 

http://www2.nature.nps.gov/geology/inventory/gre_publications.cfm 

 ZION Geologic Resource Evaluation Report 41

Appendix B: Scoping Summary 

The following excerpts are from the GRE scoping summary for Zion National Park. The 

scoping meeting occurred April 12- 13, 1999; therefore, the contact information and Web 

addresses referred to herein may be outdated. Please contact the Geologic Resources 

Division for current information. 

Executive Summary 

An inventory workshop was held at Zion National Park 

on April 12- 13, 1999 to view and discuss the park’s 

geologic resources, to address the status of geologic 

mapping by both the Utah Geological Survey (UGS) and 

the United States Geological Survey (USGS) for 

compiling both paper and digital maps, and to assess 

resource management issues and needs. Cooperators 

from the NPS Geologic Resources Division (GRD), 

Natural Resources Information Division (NRID), Zion 

NP (interpretation), UGS, USGS, Utah Geological 

Association (UGA) and Utah Bureau of Land 

Management (BLM) were present for the two day 

workshop. (see Zion NP Geological Resources Inventory 

Workshop Participants, April 12- 13, 1999) 

Day one involved a field trip led by UGS geologists Grant 

Willis and Helmut Doelling. Highlights of the field trip 

included visits to view paleontological resources within 

the Triassic Moenave Formation (Whitmore Point 

Member) where dinosaur track sites exist near the visitor 

center area, the Birch Creek landslide- dammed lake 

deposits, Crater Hill volcanic deposits, and the structural 

geology of the Hurricane fault zone and Kannarraville 

anticline. The field trip was concluded with a "team 

building" session (barbecue) at USGS Geologist Pete 

Rowley's new home in New Harmony, UT. 

Day two involved a scoping session to present overviews 

of the NPS Inventory and Monitoring (I&M) program, 

the Geologic Resources Division, and the ongoing 

Geologic Resources Inventory (GRI) for Colorado and 

Utah. Round table discussions involving geologic issues 

for Zion NP included interpretation, the UGA 

Millennium 2000 guidebook featuring the geology of 

Utah's National and State parks, paleontological 

resources, the status of cooperative geologic mapping 

efforts, sources of available data, geologic hazards, 

potential future research topics, and action items 

generated from this meeting. Brief summaries of each 

follows. 

Overview 

After introductions by the participants, Joe Gregson 

(NPS- NRID) presented an overview of the NPS I&M 

Program, the status of the natural resource inventories, 

and the geological resources inventory. 

He also presented a demonstration of some of the main 

features of the digital geologic map for the Black Canyon 

of the Gunnison NM and Curecanti NRA areas in 

Colorado. This has become the prototype for the NPS 

digital geologic map model as it ideally reproduces all 

aspects of a paper map (i.e. it incorporates the map notes, 

cross sections, legend etc.) with the added benefit of 

being a GIS component. It is displayed in ESRI ArcView 

shape files and features a built- in help file system to 

identify the map units. It can also display scanned JPG or 

GIF images of the geologic cross sections supplied with 

the map. The cross section lines (ex. A- A') are 

subsequently digitized as a shape file and are hyperlinked 

to the scanned images. 

The geologists at the workshop familiar with GIS 

methods were quite impressed with this method of 

displaying geologic maps digitally; Gregson is to be 

commended for his accomplishments. 

Bruce Heise (NPS- GRD) followed with a presentation 

summary of the up- to- date results of the Colorado GRI 

program. The status of each park area for geologic 

mapping inventories, digitizing maps, assembling 

bibliographies, preparing reports and defining 

deliverable dates for the NPS units in Colorado was 

discussed, as the Utah parks will follow a similar process. 

Interpretation 

The GRI also aims to help promote geologic resource 

interpretation within the parks and GRD has staff and 

technology to assist in preparation of useful materials 

including developing site bulletins and resource 

management proposal (RMP) statements appropriate to 

promoting geology. Jim Wood (GRD) and Melanie 

Moreno (USGS- Menlo Park, CA) have worked with 

several other NPS units in developing web- based 

geology interpretation themes, and should be considered 

as a source of assistance should the park desire. 

Zion interpreters pointed out that the park's newspaper 

has an excellent article summarizing some aspects of the 

park's stratigraphy. Also, the park's program entitled 

"Sedimentary my dear Watson" was illustrated as an 

example of a successful interpretation program in a park 

that treats geology. 

Zion interpreters said their goal is to educate the public 

that geology is not boring. A significant GPRA 

(government performance and results act) goal for the 

park is that97% of visitors will be able to understand 

some aspects of the geology, and thus there is an 

emphasis on simplifying the geology for visitors. To aid 

in this process, more graphics and brochures related to 
 NPS Geologic Resources Division 42 

the geology are desirable and should target the average 

enthusiast. These could be either black and white or full 

color (similar to the park's main brochure). It was also 

noted that supplies of such produced material should be 

always stocked instead of distributed once in a single 

mass printing. 

It was also noted that the appropriate time to promote 

geology and convey a geologic message with the visitor is 

at the time of their visiting experience when they are 

most receptive to learning, not a week later. This may 

involve trying to get them to concessions to purchase 

materials relevant to the geology so that they can further 

their interest. 

Tom Haraden (Zion NP) discussed how interpreters 

reach the general public. He believes most park visitors 

want to be around rangers and interpreters when they 

come to the area. The park has an environmental 

education person working to educate teachers on the 

geology so that when they bring their groups in, the 

teacher becomes the knowledgeable "hero" instead of 

the park staff. To this means, the park will provide props 

and other learning materials to facilitate this. Also, the 

new visitor center will feature a 90- second video display 

on the geology of the park. This should probably be 

quality assured/ quality controlled (QA/QC'd) by 

interpretive staff and geologists for accuracy prior to 

release. Several wayside exhibits are also planned to 

emphasize the geology so that the common person can 

discover geology on their own. 

Common questions asked of interpreters that involved 

geology include the following: 

• When is the next rockfall? 

• Are the rocks monitored for falls? 

• What is responsible for the colors of the rocks? 

From an ecosystem management perspective, Zion is at 

the confluence of important physiographic provinces 

(Basin and Range and Colorado Plateau), making a case 

for it as the NPS "poster- child" for promoting the 

ecosystem management concept. It is a spectacular place 

to integrate geology with biology, hydrology, 

geomorphology, vegetation and many other facets of the 

ecosystem. Flood awareness is also a major theme of 

interpretation; April 1999 was "Flood Awareness Month" 

at the park and the staff are sure to warn visitors of the 

potential for danger from this geologic process. 

UGA Guidebook on Utah’s National and State Park Areas 

Doug Sprinkel of the UGA announced that a guidebook 

treating the geology of 27 of Utah's national and state 

parks and monuments will be compiled for publication 

in September 2000. This compilation will be a snapshot 

into the geology of each park and covers most facets of 

what the GRI is trying to develop for each park for a final 

report (i.e. cross sections, simplified geologic map, 

general discussions of rocks, structure, unique aspects of 

park geology, classic viewing localities). Each author will 

be encouraged to get with NPS staff interpreters to 

develop a product that aims at a wide audience (the 

common visitor, the technical audience and the teaching 

community). Zion NP authors will be our field trip 

leaders from the UGS (Grant Willis and Helmut 

Doelling). 

Also, a CD- ROM will be distributed with the publication 

featuring road and trail logs for specific parks as well as a 

photo glossary and gallery. The photo glossary will 

describe certain geologic features (i.e. what is 

crossbedding?). These will also be available as webdownloadable Adobe Acrobat PDF files. The UGA 

cannot copyright this material because it is funded with 

state money, so it can be distributed widely and freely, 

which will also benefit the purposes of the GRI. 

Additional reprints are not a problem because of the 

digital nature of the publication and the UGA board is 

committed to additional printings as needed. UGA 

normally prints 1000 copies of their publications because 

they become dated after about five years; that will 

probably not be an issue for this publication. Prices for 

the full- color guidebook are estimated to be 

approximately $25/copy, and sales are expected to be 

high (exact estimates for Capitol Reef NM were 125 

copies/year). A website for the guidebook is forthcoming 

in October 1999. 

Field Trips will be held in September 2000. Currently, 

four field trips are scheduled: 

1. Arches NP, Canyonlands NP, Dead Horse Point State 

Park (SP) 

2. Antelope Island SP and Wasatch Mountain SP 

3. Zion NP, Cedar Breaks NM, Snow Canyon SP and 

Quail Creek SP 

4. Dinosaur NM, Flaming Gorge NRA, and Red Fleet SP 

Note: Trips 1 and 2 will run concurrently and Trips 3 and 

4 will also run concurrently. 

Many other benefits are anticipated from this publication 

and are enumerated below: 

• This type of project could serve as a model for other 

states to follow to bolster tourism and book sales 

promoting their state and its geologic features. 

• Sandy Eldredge (UGS) will be targeting teaching 

communities for involvement in the field trips; 

hopefully teachers will pass on what they have learned 

to their young audience. 

• The language is intended to appeal to someone with a 

moderate background in geology and yet will be very 

informative to the educated geologist. 

• The publication may be able to serve as a textbook to 

colleges teaching Geology of National Parks (in Utah). 

• A welcomed by- product could be roadlogs between 

parks in Utah for those visiting multiple parks, perhaps 

with a regional synthesis summarizing how the overall 

picture of Utah geology has developed. 
 ZION Geologic Resource Evaluation Report 43

Paleontological Resources 

The field trip provided glimpses into the little known 

paleontological resources of dinosaur trackways near the 

visitor center. Intern Joshua Smith has been locating and 

studying the tracks and will be giving a summary of his 

findings to the Zion interpretive staff in the near future. 

It has been suggested to keep these locations low profile 

to minimize disturbances and potential theft or 

vandalism. 

Vince Santucci (NPS- GRD Paleontologist) will be coauthoring a "Paleontological Survey of Zion National 

Park" with Josh and detailing their findings of resources 

within the park. Plants, invertebrates, and vertebrate 

tracksites are among the recognized paleontological 

resources within the Zion area. 

Similar surveys have been done for Yellowstone and 

Death Valley NP's and have shed valuable new 

information on previously unrecognized resources. 

These surveys involve a literature review/bibliography 

and recognition of type specimens, species lists, and 

maps (which are unpublished to protect locality 

information), and also make park specific 

recommendations for protecting and preserving the 

resources. 

The Death Valley Survey will be available soon. The 

Yellowstone Survey is already available on- line at: 

http://www.nature.nps.gov/grd/geology/paleo/yell_surve

y/index.htm 

and is also available as a downloadable PDF at: 

http://www.nature.nps.gov/grd/geology/paleo/yell.pdf 

Paleontological resource management plans should be 

produced for Zion involving some inventory and 

monitoring to identify human and natural threats to 

these resources. Perhaps someone on the park staff could 

be assigned to coordinate paleontological resource 

management and incorporate any findings or suggestions 

into the parks general management plan (GMP). It would 

be useful to train park staff (including interpreters and 

law enforcement) in resource protection, as the fossil 

trade "black market" has become quite lucrative for 

sellers and often results in illegal collecting from federal 

lands. 

Collections taken from this area that now reside in 

outside repositories should be tracked down for 

inventory purposes. Fossils offer many interpretive 

themes and combine a geology/biology link and should 

be utilized as much as possible in interpretive programs. 

Status of Cooperative Geologic Mapping Efforts for Zion 

UGS Perspective: 

Currently, the UGS is mapping at three different scales: 

• 1:24,000 for high priority areas (i.e. National and State 

parks) 

• 1:100,000 for the rest of the state 

• 1:500,000 for a compiled state geologic map 

The availability of funding for Zion (jointly with the 

NPS) has made it possible for these higher priority areas 

to be mapped at this detail. The UGS plans to complete 

mapping for the entire state of Utah within 10- 15 years at 

1:100,000 scale. For 1:100,000 scale maps, their goal is to 

produce both paper and digital maps; for 1:24,000 scale 

maps, the only digital products will be from "special 

interest" areas (i.e. areas such as Zion and growing 

metropolitan St. George). Grant Willis mentioned that 

the UGS simply does not have enough manpower and 

resources to do more areas at this scale. He also 

reiterated that UGS mapping goals are coincident with 

those of the National Geologic Mapping Program. 

In Zion NP, the UGS has been jointly cooperating with 

the NPS and USGS for some time on producing these 

1:24,000 quadrangles in both paper and digital format. 

Until 1995, the USGS had done major mapping projects 

under the BARCO (Basin and Range to Colorado 

Plateau) mapping program. When the USGS reorganized, 

many of these projects were put on indefinite hold. 

Fortunately, there has been mutual cooperation between 

the UGS and USGS to work together to get these 

products completed for the NPS. The NPS appreciates 

the labor of all involved parties and individuals in this 

cooperative and hopes that many products will result 

from the combined efforts of all involved agencies. 

The UGS has divided their mapping work in Zion into 

two distinct phases. The first phase involves producing 

geologic maps for the following quadrangles (see Zion 

NP Index of Geologic Maps, 1:24,000 Scale): 

• The Guardian Angels 

• Temple of Sinawava 

• Clear Creek Mountain 

• Springdale West 

• Springdale East 

All five quadrangles are field mapped and are presently in 

the internal review stage by the UGS; some field spotchecking is desirable. Some of the mapping was done 

using photogrammetric methods and some is hand 

drawn on Mylar. The UGS expects to deliver both 

completed paper and digital products by October 1, 1999. 

The original projected deliverable date was April 1, 1999, 

however, the UGS has had significant turnover with their 

GIS personnel and has requested an extension until 

October 1st. 

The second phase is beginning in spring 1999. This will 

involve geologic mapping for the following quadrangles: 

• Kolob Arch 

• Kolob Reservoir 

• Cogswell Point 

• Completion of Smith Mesa, The Barracks, and Navajo 

Lake 
 NPS Geologic Resources Division 44 

This phase will also involve completing the Smith Mesa 

quadrangle. Ed Sable (USGS) was the primary worker on 

this map but was unable to complete it due to health 

problems. The USGS and UGS are working 

cooperatively to get make sure this product is completed. 

The Barracks (southeast Zion NP) and Navajo Lake 

(south Cedar Breaks NM) are already available as 

published paper maps and will be digitized as part of this 

phase. Deliverable dates for this phase should be 

September 2001 according to Grant Willis. Upon 

completion of this phase, there will be complete digital 

coverage for Zion NP. 

Some issues have surfaced regarding the correlation of 

Quaternary deposits across quadrangle boundaries 

which have caused some delay in matching edges 

between maps of the USGS BARCO project and those of 

the UGS. The UGS would like to treat these deposits 

more in- depth. 

USGS Perspective: Pete Rowley (USGS) talked about the 

immense scope of the BARCO project for preparing 

1:100,000 scale maps for earthquake potential, mineral 

resources and various other themes. Mapping was done 

at the 1:24,000 scale and compiled at 1:100,000 scale. 

Unfortunately, this project was put on the backshelf 

because of the USGS 1995 reorganization and many of 

the original workers have not been able to realize final 

products for their previous mapping efforts. 

The UGS has essentially inherited much of Ed Sable's 

work in the Zion area since health problems wouldn't 

allow him to continue working in the field. Since the 

USGS requires digital geologic maps for all of their work, 

Pete is working with Southern Utah University's (SUU) 

Dave Maxwell to complete digitizing for Ed's BARCO 

work. It seems like the UGS has the Zion area well in 

hand, so Pete's energies will be focused on deliverables 

for the Bryce Canyon and Cedar Breaks areas. 

USGS assistance is most welcomed in completing 

quadrangles in the vicinity of Zion, Cedar Breaks, and 

Bryce Canyon because the UGS does not have personnel 

currently assigned to work in these areas. Both the USGS 

and UGS agree that the main priority is to get these 

BARCO products into usable forms and give credit 

where credit is due. The following quadrangles were 

mentioned as either being partially mapped or important 

to the regional watershed: 

• Straight Canyon 

• Flanigan Arch 

• Webster Flat 

• Mount Carmel 

• Glendale 

• Orderville 

• Long Valley Junction 

• North 

• Strawberry Point 

• Alton 

• Yellow Jacket Canyon 

• Elephant Butte 

• Hilldale 

• Cedar Mountain 

• Kannarraville 

• Smithsonian Butte 

While these quadrangles are not necessarily within an 

NPS boundary, they are part of the regional watershed 

and would be welcomed products by the NPS. Bob 

Higgins suggests trying to get NPS Water Resources 

Division (WRD) to help fund some of the mapping since 

the bedrock geology is already available and since these 

involve the watershed. 

As the park's hydrologist, Dave Sharrow would like to 

see some emphasis on studying the quadrangles east of 

Zion for water issues. From his perspective those closest 

to the Sevier fault are of most interest to him because of a 

lack of understanding of the hydrology nearest the fault. 

Pete has done a similar type of project for Nevada test 

site and would be willing to further discuss this with 

Dave Sharrow. 

There are some financing issues to consider in completing 

these quadrangles: 

• Pete would need some financial assistance in digitizing 

these maps at SUU 

• An EDMAP project may be a good way to obtain 

assistance for completing any needed field mapping 

with SUU students 

• Pete's salary and time needs to be covered by the 

USGS to work on this project 

• Other surficial specialists (Van Williams was 

mentioned) may need to be called upon to help 

complete the surficial mapping and caliche deposits; 

also numerous landslides are known for the area and 

should be mapped appropriately. Salary and time is 

also an issue for these specialists. 

A priority list for quadrangles of interest should be 

developed for SUU and estimates of costs to complete 

the work also need to be ascertained. 

Other Sources of Natural Resources Data for Zion NP 

• The UGS has a significant quadrangle database that 

they have furnished to NRID for the entire state of 

Utah. 

• NRID has compiled a geologic bibliography for 

numerous parks and monuments, including Zion. Visit 

the website at: http://165.83.36.151/biblios/geobib.nsf; 

user id is "geobib read", password is "anybody". 

• The USGS has compiled large volumes of data on the 

BARCO project that was halted in 1995; much of this 

work is unpublished and should be sought out from 

USGS personnel. 

• It was suggested that the DOE may have mineral 

exploration data for the area as there are numerous 
 ZION Geologic Resource Evaluation Report 45

mineral resources within the park (copper, iron, 

uranium, silica, cinders, gravels, coal, as well as 

hydrocarbon potential). 

• A STORET water quality report apparently exists and 

may be available from the NPS- WRD. 

• Wayne Hamilton's 1987 geologic map is digitized 

because years ago park staff needed a geologic layer 

for their GMP to define use areas within the park. 

However, it is expected that the new layers provided 

by the UGS will make this existing coverage obsolete. 

• A soils map apparently exists for the park but could 

use significant improvement. It contains adequate soil 

descriptions, but according to Laird Naylor 

boundaries are poor. It was suggested that the new 

geology layers can enhance the existing understanding 

of the soils by comparing layers. 

• Both an Archeological and Paleontological (from Josh 

Smith) database apparently exist, but there is no 

metadata, rendering it incomplete. Proposed 

coverages include a layer for floodplains, geologic 

hazards, and debris flow paths. 

• It was rumored that the park may also have a disturbed 

land sites database featuring many small dams (up to a 

few acres). It was suggested that GRD begin compiling 

and tracking this information for their disturbed lands 

programs as it is a component of the GRI. Suggested 

park contacts for this database were Laurie Kurth and 

Darla Sidles. GRD's Disturbed Lands coordinator 

(Dave Steensen) may want to attempt to contact these 

folks and obtain any available data. 

• Other disturbed land related issues included exotic 

species and channelization along the river. The river 

restoration debate involves whether the river should 

be allowed to run its course. Restoring the stream 

channel to its natural position is identified in the GMP, 

and will likely be a very expensive endeavor. 

Geologic Hazards 

There are numerous issues related to geologic hazards in 

and around Zion NP. Below is a brief list of some 

mentioned during the scoping session: 

• Landslides of April 1995, 1923, 1941, and September 11, 

1998 that resulted in taking out the park road to the 

Zion Lodge 

• Many active landslides are in the park on North Creek 

with the potential to dam creek and create lake (i.e. 

above Sunset Ridge headquarters at edge of park 

boundary) 

• A few years ago, from the Kolob Canyon section, 

portions of Interstate- 15 was washed over and vehicles 

were actually washed off of the road (this was pointed 

out to us during the field trip) because of a landslide 

from a dam collapse 

• 1992 earthquake scarp in Springdale at west entrance 

of park 

• The Hurricane Fault marks the western boundary near 

the Kolob Canyon section of the park; the actual road 

is built essentially on the fault surface 

• The potential for volcanism exists within the Zion area 

• Debris flows and rockfalls are constant sources of 

problems during rainstorms 

• Collapsible soil potential from swelling soils within the 

Triassic Chinle Formation, and windblown loess 

deposits 

• Radon is known from soils developed upon the Chinle 

Formation 

• Abandoned mineral lands (AML) for uranium mining 

near the Kolob Canyon Visitor Center 

• An existing oil well within park boundaries may pose 

the threat of mixing with groundwater and present a 

water quality breach 

• It was suggested that any future facility siting exercises 

should focus near Crater Hill 

Potential Research Topics for Zion NP 

A list of potential research topics includes studies of the 

following: 

• Study the hydrology nearest the Sevier fault zone (east 

of Zion NP) 

• Lake development and climate history 

• Study Helmutt Doelling (UGS) core to bottom of lake 

deposits; take new core to bottom of deposits 

• Lacustrine chronology from lake sediments 

• History of slope instability from landslides (try to 

ascertain ages of landslides) 

• Alluvial terrace chronology 

• River system erosion history with emphasis on 

upstream basalts 

• Fracture flow within the Navajo Sandstone because it 

is an important aquifer (Pete has student Jonathan 

Cain doing post- doc work with USGS- WRD) 

• Study of Joints for ground- water quality/quantity 

• Locations of hydrologic divides (where is the water 

going ?) 

• History of Hurricane fault as related to Basin and 

Range extension 

• Geologic Type section for Navajo Sandstone within 

the park 

• Vegetation type vs. rock type; what are the correlations 

• Development of way to date desert varnish ages;(Larry 

Snee will do it for $500,000; Pete Rowley's wife has 

worked on similar projects; she is an archeologist) 

• Color in rocks due to cementation: Navajo 

groundwater and diagenesis creating color changes 

• Paleobotanic investigations of various formations 

• Study Pack- rat middens for ecological analysis 

• Coal pit deposits 

• History of joint formation 

• Also, Tom Haraden should be consulted for his ideas 

on various interpretation and education topics; 

consult Wood and Moreno for assistance 
 NPS Geologic Resources Division 46 

Action Items 

Many follow- up items were discussed during the course 

of the scoping session and are reiterated by category for 

quick reference. 

Interpretation: 

• More graphics and brochures emphasizing geology 

and targeting the average enthusiast should be 

developed. If Zion NP needs assistance with these, 

please consult GRD's Jim Wood 

(jim_f_wood@nps.gov) or Melanie Moreno at the 

USGS- Menlo Park, CA (mmoreno@usgs.gov). 

• QA/QC of the new 90 second geology video for the 

new visitor center by geologic professionals for 

accuracy 

UGA Guidebook: 

• Attempt to plant the seeds of this concept to other 

states for similar publications involving local area 

geology. Such publications are especially useful for the 

GRI 

Paleontological Resources: 

• For now, try to minimize location disclosure of 

vertebrate tracksites to minimize disturbances and the 

potential for theft or vandalism 

• Develop an in- house plan to inventory, monitor and 

protect significant paleontological resources from 

threats; assign staff to oversee 

• Locate collections taken from the park residing in 

outside repositories 

Geologic Mapping: 

• UGS deliver to NPS all Phase 1 products (paper and 

digital) by October 1, 1999 

• UGS deliver to NPS all Phase 2 products (paper and 

digital) by September 2001 

• Maintain UGS- USGS- NPS cooperation to reap all 

possible products from existing USGS BARCO work 

to benefit the NPS GRI 

• Consult with NPS- WRD to obtain funding for 

mapping numerous quadrangles contained in regional 

watershed 

• USGS address issues relating to funding salaries and 

other work to ensure BARCO products can be 

delivered 

• USGS develop for SUU a priority list of quadrangles to 

digitize and complete field mapping, as well as 

associated estimates of time and material costs 

Natural Resource Data Sources 

• Improve the soils map for Zion NP 

• NPS- GRD Disturbed Lands Coordinator should 

consult with Zion staff about obtaining disturbed 

lands database 

Miscellaneous 

• Laird Naylor suggested that Stan Hatfield, Robert 

Eves, and Fred Lohrengel (all of SUU) and Dave 

Madsen and Lee Allison (both UGS) should be invited 

to attend the Cedar Breaks NM meeting in July 1999 

• Review proposed research topics for future studies 

within Zion NP 

Budget Items 

• The UGS has picked up 70% of the costs of mapping 

using State Map matching funds. 

• NRID I&M paid $79K in FY96 and $59K in FY98 for a 

total buy- in of $13
 ZION Geologic Resource Evaluation Report 47

Zion NP Geological Resources Inventory Workshop Participants 

NAME AFFILIATION PHONE E-MAIL 

Bruce Heise NPS, GRD (303) 969- 2017 Bruce_Heise@nps.gov 

Joe Gregson NPS, NRID (970) 225- 3559 Joe_Gregson@nps.gov 

Tim Connors NPS, GRD (303) 969- 2093 Tim_Connors@nps.gov 

Bob Higgins NPS, GRD (303) 969- 2018 Bob_Higgins@nps.gov 

Vince Santucci NPS, GRD (307) 877- 4455 Vincent_Santucci@nps.gov 

Dave Sharrow NPS, Zion NP (435) 586- 2765 Dave_Sharrow@nps.gov 

Laird Naylor BLM 

(formerly Zion NP) (801) 977- 4357 Lnaylor@ut.blm.gov 

Larry Snee USGS (303) 236- 5619 Lsnee@usgs.gov 

Pete Rowley USGS (702) 897- 4029 Prowley@usgs.gov 

Grant Willis UGS (801) 537- 3355 Nrugs.gwillis@state.ut.us 

Helmutt Doelling UGS 

Doug Sprinkel UGS/UGA sprinkel@vii.com 

Kris Thompson NPS, FOBU (307) 877- 4455 Kmt65@altavista.net 

Kyna Mallery NPS, Zion NP (435) 772- 0223 

Julie Hancock NPS, Zion NP (435) 635- 4193 Lucille@redrock.net 

Dave Grimes NPS, Zion NP (435) 772- 0223 Dave.grimes@usa.net 

Jeff Bradybaugh NPS, Zion NP (435) 772- 0208 Jeff_Bradybaugh@nps.gov 

Joshua Smith NPS, Zion NP (435) 772- 0223 Dinotrack@hotmail.com 

Sonya Berger NPS, Zion NP (435) 772- 1389 

Tom Haraden NPS, Zion NP (435) 772- 0161 Tom_Haraden@nps.gov 
 NPS Geologic Resources Division 48 

Zion National Park Index of Quadrangle Maps (1:24,000 scale). 
The Department of the Interior protects and manages the nation’s natural resources and cultural heritage; provides scientific and other information about 

those resources; and honors its special responsibilities to American Indians, Alaska Natives, and affiliated Island Communities. 

Zion National Park 

Geologic Resource Evaluation Report 

Natural Resource Report NPS/NRPC/GRD/NRR—2006/014 

NPS D-259, March 2006 

National Park Service 

Director • Fran P. Mainella 

Natural Resource Stewardship and Science 

Associate Director • Michael A. Soukup 

Natural Resource Program Center 

The Natural Resource Program Center (NRPC) is the core of the NPS Natural Resource Stewardship and Science 

Directorate. The Center Director is located in Fort Collins, with staff located principally in Lakewood and Fort 

Collins, Colorado and in Washington, D.C. The NRPC has five divisions: Air Resources Division, Biological 

Resource Management Division, Environmental Quality Division, Geologic Resources Division, and Water 

Resources Division. NRPC also includes three offices: The Office of Education and Outreach, the Office of 

Inventory, Monitoring and Evaluation, and the Office of Natural Resource Information Systems. In addition, Natural 

Resource Web Management and Partnership Coordination are cross-cutting disciplines under the Center Director. The 

multidisciplinary staff of NRPC is dedicated to resolving park resource management challenges originating in and 

outside units of the national park system. 

Geologic Resources Division 

Chief • David B. Shaver 

Planning Evaluation and Permits Branch Chief • Carol McCoy 

Credits 

Author • Dr. John Graham

Editing • Dave Sharrow and Sid Covington 

Digital Map Production • Utah Geological Survey, and Victor DeWolfe and Stephanie O’Meara 

Map Layout Design • Melanie Ransmeier
Geologic Resources Division 

Natural Resource Program Center 

P.O. Box 25287 

Denver, CO 80225 

http://www.nature.nps.gov/geology/inventory/ 

(303) 969-2090 

EXPERIENCE YOUR AMERICATM 

National Park Service 

U.S. Department of the Interior