Hovenweep National Monument 

Geologic Resource Evaluation Report 

Natural Resource Report NPS/NRPC/GRD/NRR—2004/002 

National Park Service 

U.S. Department of the Interior 

Natural Resource Program Center 

Hovenweep National Monument 

Geologic Resource Evaluation Report 

Natural Resource Report NPS/NRPC/GRD/NRR—2004/002 

Geologic Resources Division 

Natural Resource Program Center 

P.O. Box 25287 

Denver, Colorado 80225 

September 2004 

U.S. Department of the Interior 

Washington, D.C.
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gre_publications) on the internet, or by sending a request to the address on the back cover. 

Please cite this publication as: 

Thornberry-Ehrlich, T. 2004. Hovenweep National Monument Geologic Resource Evaluation 

Report. Natural Resource Report NPS/NRPC/GRD/NRR—2004/002. National Park Service, 

Denver, Colorado. 

NPS D-35, September 2004 
 HOVE Geologic Resource Evaluation Report iii

Table of Contents 

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

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

Introduction ................................................................................................................... 3

Purpose of the Geologic Resources Evaluation Program...........................................................................................3

Geologic Setting .........................................................................................................................................................3

Geologic Issues............................................................................................................. 6

Uranium and Mining Issues ........................................................................................................................................6

Slope Failures.............................................................................................................................................................6

Erosion, Seismicity, and Preservation ........................................................................................................................6

Swelling Clays ............................................................................................................................................................7

Paleontological Issues................................................................................................................................................7

Water Issues...............................................................................................................................................................7

Desert Surface Crusts (biological and physiochemical) and Desert Pavements ........................................................8

Wind Erosion and Deposition .....................................................................................................................................8

General Geology and Interpretation ...........................................................................................................................8

Oil & Gas Issues.........................................................................................................................................................9

Air Issues....................................................................................................................................................................9

Geologic Features and Processes of Special Interest............................................. 10

Square Tower Unit....................................................................................................................................................10

Horseshoe and Hackberry Units...............................................................................................................................11

Holly Unit ..................................................................................................................................................................11

Cutthroat Unit ...........................................................................................................................................................11

Cajon Unit.................................................................................................................................................................11

Goodman Point.........................................................................................................................................................11

Folds.........................................................................................................................................................................12

Faults........................................................................................................................................................................12

Formation Properties.................................................................................................. 19

Formation Properties Table ......................................................................................................................................20

Geologic History.......................................................................................................... 21

References................................................................................................................... 32

Appendix A: Geologic Map Graphic .......................................................................... 37

Appendix B: Southeast Utah Group Scoping Summary.......................................... 38

Appendix C: Hovenweep NM Scoping Summary ..................................................... 45

Attachment 1: Digital Geologic Map (CD) 
 NPS Geologic Resources Division iv 

List of Figures 

Figure 1: Location of Hovenweep NM relative to Colorado Plateau physiographic features.........................................5

Figure 2: 1919 Ruins in Square Tower Canyon ..........................................................................................................13

Figure 3: Photo of Square Tower ................................................................................................................................13

Figure 4: Ground plan of Hovenweep House ..............................................................................................................14

Figure 5: Ground plan of Hovenweep Castle ..............................................................................................................15

Figure 6: Ground plan of Twin Towers........................................................................................................................15

Figure 7: Ground plan of Unit-Type House .................................................................................................................16

Figure 8: Ground plan for Horseshoe House ..............................................................................................................16

Figure 9: Ground plan of Holly Canyon Ruins.............................................................................................................17

Figure 10: Photo of Holly Unit .....................................................................................................................................17

Figure 11: Diagram of a Normal fault in East Rock Creek canyon ..............................................................................18

Figure 12: Distribution of lithofacies during the Upper Devonian ................................................................................24

Figure 13: Lithofacies map of the Lower Mississippian Period....................................................................................25

Figure 14: Map of the Paradox Basin..........................................................................................................................26

Figure 15: Paleogeographic map of the Lower Triassic ..............................................................................................27

Figure 16: Paleogeographic map of the Lower Jurassic .............................................................................................28

Figure 17: Paleogeographic map of the Upper Jurassic .............................................................................................29

Figure 18: Location of Hovenweep NM on a tectonic map of the Laramide foreland ..................................................30

Figure 19: Geologic Time Scale...................................................................................................................................31

Figure B.1: Geologic Map Coverage, 1:24,000 scale and larger..................................................................................44
 HOVE Geologic Resource Evaluation Report 1

Executive Summary 

This report has been developed to accompany the digital geologic map derived from 

numerous published and unpublished geologic maps of the area covering Hovenweep 

National Monument in Utah. It contains information directed towards resource 

management and scientific research. National Park Service Geologic Resources Evaluation 

staff have assembled the digital geologic map that accompanies this report. 

Although created to preserve the archaeological 

treasures left by the Anasazi, Hovenweep National 

Monument preserves much more than that. Like Mesa 

Verde National Park, Chaco Canyon National Historic 

Park and the other ancient Anasazi sites in the 

southwestern United States, Hovenweep illustrates the 

dynamic relationship and delicate balance between man 

and the environment around him. 

In the late thirteenth century, this semi- arid region 

supported a vigorous agrarian population of over 2,500 

Anasazi men, women and children as well as a thriving 

trade industry with other nearby groups. The single 

most important factor responsible for their survival, and 

probably for their migration away from the area, as well, 

was the geology. The Anasazi at Hovenweep called upon 

geological resources to sustain and maintain their 

culture. 

Geology provides the foundation of the entire 

ecosystem. One stratigraphic unit of rock, the Dakota 

Sandstone, was the lifeblood of the Anasazi. The canyon 

rims upon which the Anasazi built their dwellings are 

Dakota Sandstone. The large, cohesive blocks of Dakota 

Sandstone that slumped onto the canyon floor also 

offered a foundation for some of the Anasazi’s dwellings. 

Apparently, the stone used in constructing the dwellings 

and towers came from the Dakota Sandstone. 

Furthermore, the Dakota Sandstone was the source of 

their water, without which the area was useless to them. 

The Anasazi built their dwellings near the seeps and 

springs that emerged from the Dakota Sandstone at the 

head of canyons or at the contact with the underlying 

Burro Canyon Formation. 

Understanding the geology of Hovenweep enhances 

one’s understanding of the unique relationship between 

geology and their environment. In Hovenweep National 

Monument surface exposures consist primarily of 

Jurassic, Cretaceous, and Tertiary age rocks. In their 

record oceans came and went, deserts blew sand, and 

lakes and rivers passed through. Knowing the geology in 

detail is fundamental in determining the history of 

Hovenweep and in managing and preserving what is 

there today. 

Geologic processes initiate complex responses that give 

rise to rock formations, surface and subsurface fluid 

movement, soil, and canyon formation. These processes 

develop a landscape that welcomes or discourages our 

use. 

The preservation of the canyons, dwellings, dams, ledges, 

and assorted relics of Hovenweep National Monument is 

absolutely necessary to inspire wonder in visitors to the 

sites, and emphasis of geologic resources and the story of 

Anasazi culture with regards to them should be 

encouraged so as to enhance the visitor’s experience. 

The incredible ruins and desert landscape attracted over 

32,817 visitors in the year 2002. These visitors are placing 

increasing demands on the resources available at 

Hovenweep National Monument. They were dazzled by 

the preserved dwellings, myriad of canyons and ledges, 

dams, castles, and towers. It is not surprising then that 

some of the principal geologic issues and concerns 

pertain to protecting these features. Humans have 

modified the landscape surrounding Hovenweep and 

consequently have modified its geologic system. This 

system is dynamic and capable of noticeable change 

within a human life span. 

The following features, issues, and processes were 

identified as having the most geological importance and 

the highest level of management significance to the park: 

• Erosion, seismicity, and preservation. The monument 

was created to preserve and protect some of the finest 

Anasazi ruins in the world. In the dynamic desert 

system, these features are at risk. Intense seasonal 

storms erode the canyons, undermining the 

foundations of the ruins. The region around 

Hovenweep National Monument is still seismically 

active making partial or total destruction of the ruins a 

concern. 

• Slope failures and processes. Arid desert 

environments are especially susceptible to slumping 

and landslide problems during intense seasonal storms 

due to the lack of stabilizing plant growth. Road and 

trail construction also impacts the stability of a slope. 

Mudstone rich units such as the Mancos Shale and 

Morrison Formation are typically found in outcrop as 

slopes. These slopes are prone to fail when water 

saturated. In addition to this hazardous situation, the 

mudstones of the Morrison Formation are overlain by 

the cliff forming Burro Canyon Formation. This 

creates a situation in which the Burro Canyon is 

undercut, exposing large blocks of jointed sandstone 

to the force of gravity. Rockfall and slope failure is a 

potential almost everywhere these two units are 

exposed. 
 NPS Geologic Resources Division 2 

• Water Issues. Southern Utah receives on average only 

8 to 10 inches of precipitation per year. This defines 

the semi- arid to arid climate that makes water such an 

important resource. Scant data exists regarding the 

capacity and hydrogeology of the system at the 

monument. This lack of information and monitoring 

makes managing the water resources at Hovenweep 

very difficult. 

Other geologic parameters and issues such as swelling 

clays, uranium and other mining concerns, desert crusts, 

wind erosion and deposition, oil and gas exploration, 

paleontological resources, and air pollution, were also 

identified during scoping sessions as critical management 

issues for Hovenweep National Monument. These are 

detailed on pages 9- 12. 
 HOVE Geologic Resource Evaluation Report 3

Introduction 

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

Park Service Geologic Resources Evaluation program. 

Purpose of the Geologic Resources Evaluation Program 

Geologic features and processes serve as the foundation 

of park ecosystems and an understanding of geologic 

resources yields important information needed 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. Ultimately, the inventory and monitoring of 

natural resources will become integral parts of park 

planning, operation and maintenance, visitor protection, 

and interpretation. The geologic component is carried 

out by the Geologic Resource Evaluation (GRE) Program 

administered by the NPS Geologic Resource 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 resource 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 specific 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. 

Bedrock and surficial geologic maps and information 

provide the foundation for studies of groundwater, 

geomorphology, soils, and environmental hazards. 

Geologic maps describe the underlying physical habitat 

of many natural systems and are an integral component 

of the physical inventories stipulated by the National 

Park Service (NPS) in its Natural Resources Inventory 

and Monitoring Guideline (NPS- 75) and the 1997 NPS 

Strategic Plan. The NPS Geologic Resources Evaluation 

(GRE) is a cooperative implementation of a systematic, 

comprehensive inventory of the geologic resources in 

National Park System units by the Geologic Resources 

Division, the Inventory and Monitoring (I&M) Program 

of the Natural Resource Information Division, the U.S. 

Geological Survey, and state geological surveys. 

For additional information regarding the content of this 

report please refer to the Geologic Resources Division of 

the National Park Service, located in Denver, Colorado 

with up- to- date contact information at the following 

website: 

http://www.nature.nps.gov/grd 

Geologic Setting 

Hovenweep National Monument consists of six clusters 

of ruins that straddle the Colorado/Utah border about 

40 km (25 mi) north of the Four Corners. The 785 acre 

national monument was created by a proclamation from 

President Warren G. Harding on March 2, 1923. 

Hovenweep is a Paiute/Ute word for deserted valley but at 

one time (~500 A.D.), these desolate canyons and barren 

mesas of today’s landscape echoed with the voices of 

over 2,500 Anasazi women, children, and men. Using 

local geological resources, the ancient architects built 

massive stone pueblos at the heads of canyons near 

springs and seeps emerging along the contact between 

geologic units. 

Hovenweep National Monument is part of a much larger 

geological feature called the Colorado Plateau Province 

(figure 1). Covering parts of Colorado, Utah, Arizona, 

and New Mexico, the Colorado Plateau is a region of 

high plateaus and broad, rounded uplands separated by 

vast rangelands. The rangelands are underlain by large 

elliptical basins. The structural fabric of gently warped, 

rounded folds contrasts with the intense deformation 

and faulting of the terranes bordering the Colorado 

Plateau. Northeast and east of the Colorado Plateau are 

the jagged peaks of the Rocky Mountains. The 

Mesozoic- age Overthrust Belt marks the westnorthwest edge of the Colorado Plateau. The 

extensional, normal- faulted Basin- and- Range Province 

that chopped the Overthrust Belt to pieces borders the 

Colorado Plateau to the west and south. The Rio Grande 

Rift, tearing a ragged scar in the landscape, forms the 

southeast border. Curiously, the Colorado Plateau 

remains somewhat of a tectonic mystery and has suffered 

relatively little geologic deformation compared to these 

surrounding regions. 

The Colorado Plateau is also known for its laterally 

extensive monoclines (figure 1). The basins adjacent to 

the steep limbs of the monoclines have been filled with 

sediment eroded from these folds. These uplifts and 

basins formed as a result of the Upper Cretaceous- mid 

Tertiary Laramide Orogeny. The anticlinal Monument 

Upwarp lies to the west of Hovenweep National 

Monument and forms the western border to the 

Blanding Basin, a coincident synclinal downwarp. The 

rock layers, while gently folded into anticlines and 

synclines, remain relatively undisturbed by faulting 

except in areas associated with salt structures or 

dissolution of salt structures. 
 NPS Geologic Resources Division 4 

The La Sal Mountains and the Abajo Mountains lie north 

of Hovenweep National Monument, the Ute Mountains 

lie to the southeast, and the Carrizo Mountains are 

south, across the border into Arizona. These mountain 

ranges, as well as other mountains on the Colorado 

Plateau such as the La Plata, Rico, and Henry Mountains, 

are laccoliths, the results of hot, mobile magma material 

bulging up from deep within the earth. The splendid 

peaks of the San Juan Mountains to the east are the result 

of world- class volcanic eruptions 

The giant monoclines, the laccoliths that dot the desert 

horizon, and other features present on the Colorado 

Plateau today were molded by the processes of erosion. 

The destructive forces of wind and rain, running water, 

and freezing temperatures attacked the uplifts and 

volcanoes relentlessly. The effects of erosion were 

probably negligible while the land lay very near sea level 

in the Early Tertiary Period. With a fairly abrupt increase 

in elevation from near sea level to several thousand feet 

above sea level in the Late Tertiary, however, the pace of 

erosion accelerated and attacked the Colorado Plateau 

and Rocky Mountain region with unprecedented vigor, 

carving the rocks and carrying away the dismantled 

strata to dissect the topography into the landscape we see 

today. 
 HOVE Geologic Resource Evaluation Report 5

Figure 1: Location of Hovenweep National Monument relative to Colorado Plateau physiographic features. Light gray area signifies 

the areal extent of the Colorado Plateau. Dark gray and black areas represent uplifts and mountains. 
 NPS Geologic Resources Division 6 

Geologic Issues 

A Geologic Resources Evaluation (GRE) workshop was held for Hovenweep National 

Monument from September 5- 6, 2000, to discuss the geologic resources, to address the 

status of geologic mapping by the Utah Geological Survey (UGS), and to assess resource 

management issues and needs. The following pages synthesize the results of this meeting 

to address economic resources, potential geological issues, future scientific research 

projects, and interpretive needs for Hovenweep National Monument. 

Uranium and Mining Issues 

The Paradox Basin has been the site of uranium mining 

for nearly nine decades. A discovery of a large 

unoxidized ore deposit on the flank of Lisbon Valley 

anticline, south of the monument, kindled public 

excitement in 1952 (Chenoweth, 1996). The principal 

host rocks for the radium, vanadium, and uranium 

deposits exposed at Hovenweep National Monument is 

the Jurassic Morrison Formation. In the Morrison, gray, 

poorly sorted, fine- to coarse- grained, calcareous, 

arkosic, quartz sandstone of the Salt Wash Member 

contains the uranium ore. 

Abandoned mines pose a serious potential threat to any 

ecosystem. Even in arid environments, surface water, 

runoff, and groundwater can be contaminated with high 

concentrations of heavy metals, leached from the mine 

tailings. Heavy metals may also contaminate nearby soils 

which in turn can damage the plant and animal life that 

live on the soil. 

Another threat specific to uranium mining is that of 

radon gas exposure. Radon is a daughter product of 

uranium radioactive decay and this tasteless, odorless gas 

is a known carcinogen that usually concentrates in low 

lying areas like basements and mine shafts. 

Inventory, Monitoring, and/or Research Needs 

• Conduct periodic water (surface and groundwater) 

and soil sampling and testing to detect uranium in 

those resources. Drinking water is especially 

important to monitor. 

• Research needs include a thorough investigation of 

uranium bearing beds throughout the monument 

including descriptions, uranium content tests, and 

locations, i.e. where the beds crop out and are 

accessible to the public, flora and fauna. 

• Complete inventory of the uranium content in the 

recent unconsolidated deposits and soils as well as the 

uranium bearing stratigraphic units (Morrison 

Formation).. 

Slope Failures 

Landslide and rockfall potential exists along all roads 

and trails at Hovenweep National Monument. 

These events cause road problems and closures on a 

continual basis at the monument. Certain cliff forming 

units such as the Entrada and Dakota Sandstones, and 

the Burro Canyon Formation are especially hazardous 

when undercut by a road or trail. 

Similarly, slumps and other forms of slope failure are 

common for units that are not necessarily associated 

with cliffs. Rocks rich in mudstone for instance, like the 

Morrison Formation are especially vulnerable to failure 

when exposed on a slope. The potential torrential rains 

necessary to produce flash flooding at Hovenweep also 

act as a sledgehammer on slopes lacking stabilizing plant 

and tree roots The rock and soil, suddenly saturated 

with water, slip down the slope causing a huge slump or 

mudslide/flow. 

Inventory, Monitoring, and/or Research Needs 

• Perform a comprehensive study of the 

erosion/weathering processes active at Hovenweep 

National Monument, taking into account rock 

formations, slope aspects, location and likelihood of 

instability. 

• Create a rockfall susceptibility map using rock unit 

versus slope aspect in a GIS; use the map in 

determining future developments and current 

resource management including trails, buildings, and 

recreational use areas. 

Erosion, Seismicity, and Preservation 

The ancient Puebloans built their dwellings near springs 

and seeps. Groundwater percolated through the porous 

Dakota Sandstone until it encountered the impermeable 

shale of the Burro Canyon Formation. At this contact, 

the water was forced outward along the canyon walls. 

Dams were built to retain water and recharge 

groundwater. Today, these natural processes present a 

management challenge as they continue to undercut and 

erode the canyon walls and individual cultural units. 

The Square Tower boulder foundation is eroding. A 

study of the problem and subsequent report was 

delivered to the Geologic Resources Division (GRD). A 

summary of that report is available on the HOVE 

website. Briefly, a consolidant was found that, when 

injected into the porous sandstone, slows the erosion 

process. 
 HOVE Geologic Resource Evaluation Report 7

Earthquake potential is high along the Moab Fault in 

nearby Arches National Park, Southeast Utah Group 

(SEUG). While this and other faults in the Paradox Basin 

are associated with salt structures, the Colorado Plateau 

interior does possess a low level of seismic hazard (Wong 

et al., 1996). Ground shaking from earthquakes may 

impact the ancient structures at Hovenweep National 

Monument causing catastrophic destruction. 

Inventory, Monitoring, and/or Research Needs 

• Use high resolution Global Positioning System (GPS) 

to detect moving, swelling, and collapse in areas of the 

monument. 

• Obtain access to regular seismic activity reports or a 

seismometer to measure activity in the area. 

• Perform a comprehensive, large scale, exhaustive map 

study of the canyons and buildings to determine 

minute points of susceptibility to failure and to better 

understand the structures and their weaknesses. 

• Expand on the work that was done regarding the 

Square Tower unit, research that would carefully 

define the diagenetic history of the rocks and the 

cements that hold the grains together. A part of this 

study could incorporate the present effects of meteoric 

groundwater on the cement, pore space, and origin of 

diagenetic minerals. 

Swelling Clays 

Swelling soils associated with bentonitic shales of the 

Morrison, and Mancos Formations may be a concern to 

the present and future developments and management at 

Hovenweep National Monument. Bentonite, a clay 

derived from altered volcanic ash deposits, and is 

responsible for the road failures at Mesa Verde National 

Park among others. Bentonite has the ability to absorb 

large quantities of water into its structure so it will swell 

when wet and shrink upon drying, causing the ground 

surface to heave and buckle. Any structures, roads, trails, 

facilities, etc. found on soils with large concentrations of 

this mineral will be profoundly impacted and potentially 

destroyed. 

This shrink- swell characteristic of bentonite produces 

interesting construction and road maintenance 

problems, but becomes a valuable property to the oil 

industry where bentonite is used to cool drilling bits and 

seal fractures. 

Inventory, Monitoring, and/or Research Needs 

• Use GIS to determine where trails, roads and buildings 

are present on bentonitic units. This method should 

also be employed to determine high risk areas where 

future development should be avoided. 

• Perform an exhaustive mapping study of where 

specific bentonitic beds are located in the units listed 

above (Morrison Formation and Mancos Shale) to 

allow for more precise hazard assessment. 

Paleontological Issues 

The Geologic Resources Division of the National Park 

Service is conducting a separate paleontological 

inventory of the National Parks and Monuments so a 

detailed description of the paleontology and 

biostratigraphy of Hovenweep National Monument is 

beyond the scope of this inventory. The only report of 

paleontological resources from the monument is an 

unidentified bone found by Martha Hayden, a Utah 

Geological Survey geologist (Santucci, 2000). As has 

been noted, however, the Dakota Sandstone contains 

fossil pelecypod fauna. These and other invertebrate 

fossils are probably present in the monument, but no 

detailed study of the fossil material has been conducted. 

Inventory, Monitoring, and/or Research Needs 

• Research projects might be supported that would help 

identify the paleontological resources of the park as an 

aid to the GRD paleontological survey. 

Water Issues 

As true today as in the past, both surface water and 

groundwater play key roles in defining and shaping the 

Hovenweep landscape. Flowing water, however 

intermittent, helps carve the deep canyons, entrenched 

rivers, mesas, and spires that are so prevalent on the 

Colorado Plateau. Groundwater dissolves the cement 

that binds grains together and transports the cementing 

elements out of the system through seeps and springs. 

This erosion undercuts cliffs forming, alcoves, and rocks 

topple to the base of canyons. Water also expands as it 

freezes, pushing the grains apart, and when it thaws, the 

rocks collapse. In addition, the quality and quantity of 

water dictates biodiversity and the success of human 

occupation in an area. 

The climate of Hovenweep is one of low precipitation 

and high evaporation rates. Consequently, recharge to 

groundwater aquifers is low. In the canyons, permeable 

Dakota sandstone overlies impermeable Burro Canyon 

shale and creates a favorable environment for seeps and 

springs. Water from rain and snow soaks into the 

sandstone but vertical flow is interrupted at the contact 

with the shale. The water is then forced outward, along 

the contact, and when it reaches the canyon wall, it forms 

a spring. Even in dry drainages, cottonwood trees in the 

canyon bottoms locate seeps and springs or areas where 

groundwater is near the surface. 

All of these factors were taken into account when the 

Puebloan peoples settled the cluster of dwellings that 

became Hovenweep National Monument. Earthen 

dams, such as those at the Cajon ruins and near the 

remains of Hovenweep House in the Square Tower 

group, were constructed above springs in order to 

capture the precious water. Without the dams and with 

little vegetation to intercept the water, the rainfall and 

snowmelt quickly disperse as surface runoff. With the 

dams, the water collected in pools and slowly percolated 

downward to recharge the spring or slowly flow to 

garden plots. 
 NPS Geologic Resources Division 8 

The hydrology of the area may have served a spiritual, as 

well as a practical, role in ancient Puebloan culture. In 

contemporary Puebloan culture, springs are special 

locations associated with the creation of Puebloan 

peoples. Given the cultural significance of water at 

Hovenweep, it stands to reason that extensive study of 

the hydrogeologic system would lend to a deeper 

understanding of the interactions between landforms, 

water, and the inhabitants of the land. As yet, the system 

is poorly understood at Hovenweep. 

Inventory, Monitoring, and/or Research Needs 

• Conduct hydrogeologic studies to define subsurface 

flow patterns, regional and local flow systems, and the 

conductivity and transmissivity of the strata at 

Hovenweep. 

• Monitor water quality on a multiple sample location 

basis within the monument, drinking water sources are 

especially important. 

• Develop an understanding of groundwater and surface 

water flow in relation to erosion rates is critical to the 

survival of many of the dwellings at the monument. 

• Define the hydrology of the area and of seeps along 

with the water quality, to establish a baseline for 

comparison. Water quality was mentioned at the 

workshop as a concern because of the numerous seeps 

along geologic units 

• Install further wells for testing and drinking water 

access. 

• Determine the impacts of copper and uranium mining 

and oil and gas drilling. 

• Identify and study potential sources for groundwater 

quality impacts. 

• Install transducers and dataloggers in wells. 

• Investigate additional methods to characterize 

groundwater recharge areas and flow directions. 

Desert Surface Crusts (biological and physiochemical) 

and Desert Pavements 

Biological soil crusts composed of varying proportions of 

cyanobacteria, lichens, and mosses are important and 

widespread components of terrestrial ecosystems, and 

greatly benefit soil quality and ecosystem function. These 

plants increase water infiltration in some soil types, 

stabilize soils, fix atmospheric nitrogen for vascular 

plants, provide carbon to the interspaces between 

vegetation, secrete metals that stimulate plant growth, 

capture nutrient- carrying dust, and increase soil 

temperatures by decreasing surface albedo. They affect 

vegetation structure directly due to effects on soil 

stability, seedbed characteristics, and safe- site 

availability, and indirectly through effects on soil 

temperature and on water and nutrient availability. 

Decreases in the abundance of biological soil crusts 

relative to physicochemical crusts can indicate increased 

susceptibility of soils to erosion and decreased 

functioning of other ecosystem processes associated with 

biological crusts. Physiochemical crusts can protect soils 

from wind erosion but not water erosion, and do not 

perform other ecological functions of biological crusts. 

Inventory, Monitoring, and/or Research Needs 

• Inventory condition and distribution of biological soil 

crusts. 

• Investigate connection between ecosystem function 

and biological crusts. 

• Map crust communities in relation to environmental 

factors. 

• Study crust recovery rates and susceptibility to change. 

• Study crust population dynamics and conditions. 

Wind Erosion and Deposition 

In addition to water, wind is a major force that can 

redistribute soil and soil resources (e.g., litter, organic 

matter, and nutrients) within and among ecosystems. 

Erosion and deposition by wind is important at 

Hovenweep and can be accelerated by human activities. 

Accelerated losses of soil and soil resources by erosion 

can indicate degradation of arid- land ecosystems 

because ecosystem health is dependent on the retention 

of these resources. In addition, wind erosion and 

sediment transport may be strongly impacted by landuse practices outside the parks. Eolian sand from 

disturbed surfaces may saltate onto undisturbed ground, 

burying and killing vegetation and/or biological soil 

crusts, or breaking biological soil crusts to expose more 

soil to erosion. Because park management practices limit 

or prohibit off- road travel, human impacts within the 

parks primarily are associated with off- trail hiking in 

high- use areas. Where livestock grazing or trailing is still 

permitted, accelerated soil erosion can be more 

extensive. 

Inventory, Monitoring, and/or Research Needs 

• Monitor movement of soil materials. 

• Investigate impacts to the ecosystem of soil movement. 

• Investigate natural range of variability of soil 

movement in relation to landscape configuration and 

characteristics. 

General Geology and Interpretation 

The unique geology of Hovenweep National Monument 

lends itself to potential scientific research projects that 

address the Mesozoic stratigraphy, the regional and local 

hydrology, and weathering/erosion rates. 
 HOVE Geologic Resource Evaluation Report 9

Although the Mesozoic strata have been studied in detail 

in other locations on the Colorado Plateau, the strata at 

Hovenweep have not. Detailed descriptions of the 

depositional environments, the depositional systems, and 

the bounding unconformities are lacking. Furthermore, 

the flat- lying beds are deceptive. They overlie folded 

and faulted strata, and while seeming to represent 

passive, horizontal deposition, the surface layers are the 

signatures of dynamic tectonic processes resulting from a 

complex depositional and tectonic history. 

The science of stratigraphy has undergone dramatic 

changes in the last twenty years and the strata at 

Hovenweep should be integrated into regional 

interpretations of the Jurassic and Cretaceous 

depositional regimes. Unconformities need to be 

identified and depositional environments defined on a 

bed- by- bed level of detail. The depositional 

environments, bounding unconformities, and 

depositional geometry of the Burro Canyon Formation 

and Dakota Sandstone need to be evaluated and 

integrated into a regional stratigraphic synthesis. The 

strata at Hovenweep are necessary pieces to this regional 

puzzle. 

Inventory, Monitoring, and/or Research Needs 

• Perform rock color studies. 

• Identify unconformity- bounded stratigraphic 

packages in order to better define the depositional 

systems present in the past. 

• Develop more graphics and brochures emphasizing 

geology, targeting the average enthusiast. Noted at the 

workshop was a need for a pamphlet or trail guide that 

describes the geology of Hovenweep National 

Monument for the visitor. Since geology is a strong 

component of the park, a geologic trail guide might 

enhance the visitor’s experience. 

• Develop an informative trail guide based on the detail 

GIS- NPS geologic map which has been published for 

Hovenweep National Monument. This would accent 

the strong geological component of the park and 

enhance the visitor’s experience while at Hovenweep. 

• Determine a timeline of canyon incision on the 

Colorado Plateau. The timing of canyon incision on 

the Colorado Plateau is an important topic of 

discussion among Quaternary geologists. Incision and 

erosion are directly related to weathering rates and 

regional tectonic regimes. 

• Hire a full- time geologist to handle geologic issues for 

the SEUG. 

Oil & Gas Issues 

The combination of salt, organic- rich shale, porous 

limestone and sandstone, pressure and time has resulted 

in large accumulations of oil and gas in the Paradox 

Basin. Since the discovery of the giant Aneth Field in 

1956, the Paradox Basin has been a prolific producer of 

oil and gas (Baars et al., 1988). 

The oil fields in southeastern Utah lie east of the 

Monument Upwarp in the vicinity of Hovenweep 

National Monument (Harr, 1996). 

While not necessarily present within the monument, oil 

and gas accumulations surrounding the monument area 

pose a threat to the monument’s viewshed and 

ecosystem. Geophysical exploration, the influx of drills, 

rigs and extraction equipment necessary for oil and gas 

production can create new road construction, water 

pollution, noise pollution and a localized population 

increase. 

Inventory, Monitoring, and/or Research Needs 

• Park staff should remain aware of the potential 

encroachment of oil and gas exploration in the area of 

the park. 

• Acquire plugging records of oil and gas wells 

potentially connected to park groundwater systems. 

Air Issues 

Harmful chemicals and particulates are responsible for 

increased acid deposition in southern Utah. Sources of 

these dangers materials include the Navajo Power Plant, 

the Four Corners Plant, the Emery Plant and the 

Huntington Plant. Acid in the form of acid rain can 

dramatically affect the geologic landscape by 

preferentially eroding and weathering carbonate layers, 

intergranular cements and entire units of rock. This 

preferential erosion, accelerated by increase acidity of 

rainfall, can destabilize surfaces along slopes and cliffs 

causing significant hazards. 

Inventory, Monitoring, and/or Research Needs 

• Monitor rainwater pH, noting spikes or changes. 

• Establish a working relationship with the appropriate 

industries in an attempt to decrease the level of 

pollutants in the area over the monument. 
 NPS Geologic Resources Division 10 

Geologic Features and Processes of Special Interest 

Although present in the Hovenweep area from about 500 

A.D., midway through the twelfth century, the 

Hovenweep Anasazi expanded their use of geologic 

resources and began building massive stone pueblos 

encircling the canyon heads. Nineteenth- century 

explorers referred to these structures as castles (Noble, 

1991). Within the canyons, often below a spring, these 

people built tall stone towers that exhibit expert masonry 

skills and engineering. By the end of the thirteenth 

century, the Anasazi, including those at Hovenweep, 

mysteriously left the Four Corners region, never to 

return. 

The square, oval, circular, and D- shaped towers at 

Hovenweep remain an enigma. Constructed with 

virtually no windows and in at least one case, without a 

door, the towers stand as timeless sentinels of a longforgotten culture that thrived in the desert. Were they 

used as lookouts? Did they guard precious springs? 

Were they signal towers or used for celestial 

observations? Were they granaries or water reservoirs? 

Or, did Anasazi use them for ceremonies or general 

habitation? While some of the mysteries of the Anasazi 

remain, the foundation upon which the Anasazi built 

their culture at Hovenweep can be defined by looking at 

the geology. 

The ruined castles and towers of Hovenweep National 

Monument are marvelously well preserved. Some of the 

best castles and towers are located in three canyons: 1) 

Square Tower Canyon, 2) Holly Canyon, and 3) 

Hackberry Canyon. 

Square Tower Unit 

The hydrology of the area, while allowing human 

habitation, is also responsible for the slow disintegration 

of the ancient ruins of Square Tower (figure 2). Spread 

along both sides of a Y- shaped canyon capped by 

Dakota Sandstone, the Square Tower Group contains the 

most concentrated remains of buildings at Hovenweep. 

Square Tower itself is a three story high tower built on a 

slump block of Dakota Sandstone (figure 3). The 

sandstone is very porous, poorly cemented, and badly 

honeycombed with solution hollows along bedding 

planes. Consequently, weathering and erosion has 

caused some concern about the stability of Square 

Tower. A study conducted between 1991 and 1994 

achieved some success at slowing erosion by using 

Conservare OH, a solution of ethyl silicate and methyl 

ethyl ketone. The solution absorbs into the pores of the 

rock and forms a silica gel cement. This process 

strengthens the bond between sand grains. Significantly, 

the solution does not completely fill the pore spaces and 

thus, water may continue to flow through the rock. 

 If water is trapped behind an impervious surface, 

spalling may occur. The solution also did not alter the 

appearance of the rock. Groundwater in samples did 

seem to inhibit the absorption of the consolidant, but if 

the solution was applied following a long dry spell, the 

rock may be strengthened without harming it 

aesthetically (Griffitts, 1994; 

www.nps.gov/hove/sqtower.htm). 

While many of the ruins now grace the canyon rims, the 

canyons probably widened by rock collapse as 

groundwater and surface water undermined the soft 

Dakota sandstone. Hovenweep House (figure 4) and 

Hovenweep Castle (figure 5) now rest on the canyon rim 

and Tower Point is presently located at the center of the 

Y- shape of the canyon (figure 2). Hovenweep House is 

the largest ruin in the canyon and sits at the head of the 

South Fork. The ruins contain a multichambered, 

semicircular D- shaped tower. Hovenweep House is 

similar to Far View House on the Mesa Verde (Fewkes, 

1919). Like other ruins, Hovenweep Castle has circular 

kivas embedded in rectangular rooms (figure 5). Tower 

Point appears to be a lone tower but the canyon was once 

filled with dwellings. As at Hovenweep Castle, buildings 

likely extended from the canyon bottom to the canyon 

rim at Tower Point. Stronghold House (figure 2) and 

Stronghold Tower were once connected by a log that 

bridged a crevice in the canyon. The slow, relentless 

process of canyon widening by slumping would have 

destroyed many of the dwellings and may impact the 

present structures in the future. Slump blocks and 

boulders also became building sites. Eroded Boulder 

House (figure 2) was constructed within a cave of a large 

boulder that came to rest below the canyon rim. 

The Twin Towers (figure 6) overlook Eroded Boulder 

House from the canyon rim. These towers are a pair of 

two- story apartment- type buildings with sixteen rooms. 

In 1919, as today, the Twin Towers ruins ranked among 

the most impressive buildings in Square Tower Canyon 

(Fewkes, 1919). The towers stand on the south side of the 

canyon on a rock that is isolated by a cleft from the 

adjoining cliff. Small caves were walled up below the 

foundation on the northwest base of the larger room. 

Unit- type House rests on the very edge of the canyon on 

the North Fork (figure 7) and is the simplest form of 

prehistoric pueblo (Fewkes, 1919). Rectangular rooms 

surround the centrally placed circular ceremonial room. 

The external form is oriented about due north. The 

central kiva sports exceptionally fine masonry and 

evidence of mural banquettes and pilasters to support 

the roof. The kiva with its vaulted roof is similar to 

Spruce- tree House, Cliff Palace, and Far View House on 

the Mesa Verde.

 
 HOVE Geologic Resource Evaluation Report 11

Horseshoe and Hackberry Units 

Horseshoe House is located along the Canyon Rim Trail 

that connects Tower Point Ruin, Horseshoe House, and 

the Hackberry Site. The precision of the ancient 

architects and their use of natural products are 

magnificently displayed at Horseshoe House (figure 8). 

Each stone was carved to fit and mortar made from clay, 

sand, and ash, mixed with water from seeps in the 

canyon below was used to hold the stones in place. This 

mortar still holds the walls together, 800 years after they 

were constructed. 

Hackberry Unit, as mentioned previously, may have had 

one of the largest populations of all the Hovenweep units 

because of its proximity to a constant seep of water. 

Archaeologists speculate that 250 to 350 people may have 

lived in the Hackberry Unit 

(www.nps.gov/hove/hshoe.htm). 

Holly Unit 

Located at the head of Keeley Canyon, the Holly Site 

includes Tilted Tower and Boulder House (figure 9). 

Tilted Tower is a multi- story pueblo built atop a large 

Dakota sandstone boulder. Processes of erosion and 

weathering caused the boulder to shift sometime after 

the canyon was abandoned (A.D. 1300). The upper 

stories of the tower tumbled into the canyon. 

Boulder House (this may be Fewkes’ Holly Tower, 1919) 

was also built on a Dakota Sandstone boulder, but in this 

case, the boulder is on the canyon bottom (figure 10). 

Like many towers at Hovenweep National Monument, 

Boulder House is located adjacent to a seep. 

Cutthroat Unit 

A breathtaking view awaits the visitor to Cutthroat 

Castle. Cajon Mesa stretches to the south towards the 

San Juan River and Carrizo Mountains. The buttes and 

towers of Monument Valley can be seen to the southwest 

and the volcanic spire of Shiprock in northwestern New 

Mexico pierces the sky to the southeast. This view was 

certainly not lost on the ancestral Puebloans who settled 

in this area. 

The climate, elevation, and wind- blown dust gave rise to 

a soil that supported a forest of piñon and juniper trees. 

These provided the Puebloans with a variety of useful 

products. Piñon seeds are rich in calories and protein. 

Piñon sap or pitch waterproofs and seals baskets. 

Clothing and sandals can be made with shredded juniper 

bark. Trees were burned in fires and used as building 

materials. The tree rings give archeologists an accurate 

age date for many of the structures. 

Like today, the soil also supported sagebrush. Sagebrush 

flowers, seeds, and leaves were all part of the prehistoric 

diets. Sagebrush is a good source of iron and Vitamin C 

and will kill intestinal parasites if eaten in larger amounts. 

Quaternary uplift and erosion also played a role at 

Cutthroat Castle. Quartz pebbles from stream beds were 

used to make stone tools such as knives, scrapers, and 

projectile points. 

Cajon Unit 

About 80 to 100 people lived in the village that makes up 

the Cajon Unit. As with the other sites, erosion and 

weathering have taken their toll on the dwellings. The 

surviving structures are located around the head of a 

small canyon, but other buildings have fallen victim to 

canyon widening processes and have been reduced to 

rubble. Small cliff dwellings are protected under the 

ledge of one canyon wall. A tower with stones fitted to 

the undulations of three large boulders attest to the skill 

and determination of the architects and masons of 

Hovenweep and are reminiscent of the masonry at 

Navajo National Monument in northeastern Arizona. 

Goodman Point 

Except for Goodman Point, the ruins represent groups of 

farming communities with sophisticated stone masonry 

buildings on the northern edge of the Upper Sonoran 

Desert (NPS, 1990). On the desert, the location of the 

Anasazi communities was controlled by the geology and 

hydrogeology. 

These Anasazi took advantage of the geology of the area 

by building at the head of draws and ravines where the 

strata produce springs and seeps. They manipulated and 

conserved the precipitation by building check dams and 

reservoirs in a region that is too dry for modern dryfarming methods (NPS, 1990). 

Unlike the other Hovenweep sites, Goodman Point is 

not in a desert. Rather, it sits in the midst of modern dry 

land farms that produce pinto beans and winter wheat. 

The significance of Goodman Point lies in its sheer size 

and complexity. Anasazi communities in Montezuma 

Valley were contemporaries with the Mesa Verde 

Anasazi. Goodman Point was one of the largest 

prehistoric settlements in the valley, at least twice the size 

of Cliff Palace at Mesa Verde. The ruins represent the 

climax of the lifestyle of the Mesa Verde or Northern San 

Juan branch of the Anasazi. 
 NPS Geologic Resources Division 12 

Folds 

During the Laramide orogeny, the last major mountainbuilding event to affect the Central Rocky Mountains, 

the Colorado Plateau was folded into broad arches and 

basins. Hovenweep is located on the gentle southwestdipping slope of the Blanding Basin, one of these broad 

basins formed during the Laramide orogeny (Haynes et 

al., 1972; Woodward, 1988). Structural contours drawn 

on the base of the Dakota Sandstone show the Blanding 

Basin as a northwest- southeast trending structural 

trough, plunging to the southeast, bordered by 

Laramide- age uplifts. The Monument Upwarp lies to the 

west and the Defiance Uplift to the south (figure 1) 

(Haynes et al., 1972; Woodward, 1988). 

Additional folds mapped on the eastern half of the 

Hovenweep geologic map appear to be younger than the 

Laramide structures, and may be associated with the 

processes that formed Ute Mountain and McElmo 

Dome, southeast of the Monument (Ekren and Houser, 

1965). The anticlines and synclines on the geologic map 

are plunging folds trending east- west. The Aneth 

Anticline in the southwestern portion of the map is 

associated with the Aneth oil field that was developed 

farther to the west. Petroleum exploration wells mapped 

in association with the eastern plunge of the fold have all 

been dry. A portion of the Dove Creek Anticline enters 

the map area in the northeast corner of the map. 

Goodman Point lies between the McElmo Syncline and 

an unnamed anticline that has been mapped in the 

Dakota and Morrison Formations. The trace of each 

fold axis disappears beneath Quaternary alluvium. 

A laccolithic igneous intrusion in the Tertiary formed the 

Ute Mountains. The McElmo Dome, north of the Ute 

Mountains, may also be of igneous origin (Ekren and 

Houser, 1965). An oil well drilled into the central part of 

the McElmo Dome bottomed in igneous rock that could 

be related to those at Ute Mountain. The primary 

difference between the two uplifts lies in the geometry of 

their satellite folds. Long, relatively narrow anticlines 

that plunge radially away from the central structure 

characterize the McElmo structure (a significant carbon 

dioxide producer). The Ute dome, on the other hand, is 

characterized by broad flexures that lose definition a 

short distance from the central part of the structure 

(Ekren and Houser, 1965). 

The structural configuration of the McElmo Dome may 

also have resulted, in part, from salt movement. 

Movement of Pennsylvanian age salt deposits in the 

Paradox Formation is responsible for the extensive salt 

anticlines that form a northwest- southeast trend on the 

Colorado Plateau. Salt Valley in Arches National Park to 

the north formed when the salt- cored anticline 

dissolved and collapsed. The igneous rocks intruded 

into the Paradox Formation (Ekren and Houser, 1965). 

Faults 

Steeply dipping normal faults are associated with the Ute 

Mountains and McElmo Dome, but they are not 

prevalent at Hovenweep National Monument. South of 

the Goodman Point unit, on the southern edge of the 

map, two normal faults of little displacement are present 

(figure 11). Both fault traces are inferred, however, as are 

the geologic contacts. The northwest- southeast 

trending fault mapped in the Westwater Canyon member 

of the Morrison Formation drops down to the south 

whereas the east- west fault mapped in the Salt Wash 

member of the Morrison Formation has a hanging wall 

that has moved north relative to the footwall. 

At the Naraguinnep Reservoir in the northeast corner of 

the map, an outcrop of Mancos Shale defines the 

footwall of a northeast- southwest trending fault within 

the House Creek Fault zone. The hanging wall has 

moved down to the north relative to the footwall and 

juxtaposed Mancos Shale against the older Dakota 

Sandstone. In the Hovenweep area, the House Creek 

Fault dies out to the west beneath Quaternary eolian 

deposits without offsetting the Dakota Sandstone. On a 

Precambrian basement lineament map, the northeast 

trending House Creek fault terminates at the juncture 

with a major northwest trending lineament just 

northwest of the Ute Mountains (Harr, 1996). During 

the Pennsylvanian, left- lateral, strike- slip movement 

occurred along the House Creek Fault. 
 HOVE Geologic Resource Evaluation Report 13

Figure 2: Ruins in Square Tower Canyon, Hovenweep National Monument, in 1919. Ruins: 1) Hovenweep House; 2) Hovenweep 

Castle; 3) Square Tower; 4) Tower Point; 5) tower walls rising from a ledge above the arroyo; 6) small tower at base of talus slope; 7) 

Eroded Boulder (Bowlder) House; 8) Twin Towers; 9) ruin walls; 10) Unit-Type House; 11) Stronghold House (cluster of several small 

buildings); 12) not described; 13) Stronghold Tower (?). Sketch from Fewkes, 1919. 

Figure 3: Square Tower at Hovenweep National Monument built on a slump block of Dakota Sandstone. The sandstone is being 

eroded due to the presence of a nearby stream. The National Park Service built the stabilizing wall below the boulder in 1960. 

Photograph by Anne Poole, NPS. 
 NPS Geologic Resources Division 14 

Figure 4: Ground plan of Hovenweep House, Square Tower Canyon, Hovenweep National Monument. High walls stand at the 

northwest angle of the ruin (A). Although walls have fallen, still remaining is a semicircle great house (B, C, D), kivas (K), and massive 

walls on the south side (E). Sketch from Fewkes, 1919. 
 HOVE Geologic Resource Evaluation Report 15

Figure 5: Ground plan of Hovenweep Castle, Square Towers Canyon, Hovenweep National Monument. Massive-walled semicircular 

towers (M, L) are connected in an L-shape by great houses and square rooms (A-I). Depressions indicate kivas (K). Sketch from

Fewkes, 1919. 

Figure 6: Ground plan of Twin Towers, Square Towers Canyon, Hovenweep National Monument. Letters A-I indicate rooms in the 

towers. Sketch from Fewkes, 1919. 
 NPS Geologic Resources Division 16 

Figure 7: Ground plan of Unit-Type House, Square Towers Canyon, Hovenweep National Monument. Rooms A-F clustered around a 

central kiva (K). A small room (G) may have held ceremonial objects. From Fewkes, 1919 

Figure 8: Ground plan for Horseshoe House, Horseshoe (Hackberry) Canyon. A tower (4) stands on the canyon rim. Ruins (2, 3) are 

also on canyon rims. Sketch from Fewkes, 1919. 
 HOVE Geologic Resource Evaluation Report 17

Figure 9: Ground plan of Holly Canyon Ruins, Holly Canyon, Hovenweep National Monument. Two towers (C, D) are constructed on 

fallen boulders. Ruins A and B stand on the rim of the canyon. Ruin A is the largest building of the group. The entrance to Ruin B 

may have been through the floor. Ruins E and F were once part of Holly House, a pueblo that was of considerable size. Sketch from 

Fewkes, 1919. 

Figure 10: Holly Unit, Hovenweep National Monument. Dwelling is constructed on Dakota Sandstone that has subsequently been 

subjected to erosion, leaving the ruin in a precarious position. This is probably the ruin called “Holly Tower” in Fewkes, 1919, (figure 

9, C). Photograph by Anne Poole, NPS. 
 NPS Geologic Resources Division 18 

Figure 11: Normal fault in East Rock Creek canyon (red line), north of Ute Dome and southwest of Goodman Point Unit, showing offset 

in the Entrada Sandstone (Je), Wanakah Formation (Jw), Junction Creek Sandstone (Jj), and the Salt Wash (Jms) and Westwater 

Canyon(Jmw) members of the Morrison Formation. Fault block on the left side of the fault has moved up (U) relative to the fault block 

to the right of the fault which has moved down (D). Photograph by Anne Poole, NPS. 
 HOVE Geologic Resource Evaluation Report 19

Formation Properties 

This section serves as a critical link between resource managers and the geologic map of 

the park. Formation Tables are highly generalized and for informational purposes only. 

Ground disturbing activities should not be permitted or denied on the basis of 

information contained in these tables. More detailed unit descriptions can be found in 

the help files accompanying the digital geologic map or by contacting the Geologic 

Resources Division at 303- 969- 2090. 

The dwellings at Hovenweep National Monument are 

founded on the relatively flat- lying, Cretaceous- age 

Dakota Sandstone that caps the small canyons cut into 

the Cretaceous Dakota Sandstone and Burro Canyon 

formations and the Jurassic Morrison Formation and San 

Rafael Group (Hackman, 1955; Haynes et al., 1972). 

Although mapped as a formation separate from the 

Morrison Formation on the geologic map (Appendix A, 

Attachment 1) (Haynes et al., 1972), the Junction Creek 

Sandstone is now recognized as correlative to the Bluff 

Sandstone, a basal member of the Morrison (Peterson, 

1994; Baars, 2000). The members of the Morrison 

Formation and the Cretaceous Dakota Sandstone and 

Burro Canyon Formation are the more prevalent rock 

units found in the monument, but the formations of the 

San Rafael Group are exposed in a canyon cut southwest 

of the Goodman Point ruins. 

Between the deposition of the Mancos Shale and the 

unconsolidated deposits of recent, Quaternary valley fill 

and terrace deposits, approximately 80- 90 million years 

of earth history has been eroded from this landscape. 

Today, the Quaternary silts, sands, and gravels that are 

sparsely preserved in the canyons and surface 

depressions represent only a fraction of the deposits that 

once spread across this area only to be subsequently 

stripped from the Plateau by the relentless processes of 

uplift and erosion. 

The following page presents a table view of the 

stratigraphic column and an itemized list of features per 

rock unit. This sheet includes several properties specific 

to each unit present in the stratigraphic column 

including: map symbol, name, description, resistance to 

erosion, suitability for development, hazards, potential 

paleontologic resources, cultural and mineral resources, 

potential karst issues, recreational use potential, and 

global significance. 
 NPS Geologic Resources Division 20 

Formation Properties Table 
 HOVE Geologic Resource Evaluation Report 21

Geologic History 

Preserved Precambrian history began on the Colorado 

Plateau in the Proterozoic about 1,800 – 2,000 Ma when 

muddy sandstones (graywacke), shales, and volcanic 

rocks were deposited in a vast oceanic environment. 

Erupting volcanoes formed a chain of islands in this 

ocean beyond the southern edge of the North American 

craton (Reed et al., 1987; Scott et al., 2001). A period of 

compressive mountain building folded the Precambrian 

strata into tight, chevron- like folds and metamorphosed 

the rocks to gneisses about 1,740 Ma as the volcanic 

islands collided with the southern end of what is now 

Wyoming (Hutchinson, 1976; Tweto, 1980: Warner, 1980; 

Gregson, 1992; Scott et al., 2001). Metamorphosed 

sedimentary rocks and volcanic rocks over 1,800 million 

years old are present in exposed terranes throughout 

Colorado and in the buried basement of the Colorado 

Plateau (Tweto, 1980). 

Late Proterozoic rifting created a new continental 

margin along western North America. During the Late 

Precambrian through the Cambrian, thousands of feet of 

shallow- water, marine sediments accumulated along a 

passive plate- tectonic margin on the western side of the 

Transcontinental Arch, an upland that stretched from 

northern Minnesota southwestward across Nebraska, 

Colorado and northwestern New Mexico (Speed, 1983; 

Sloss, 1988). 

Throughout the Paleozoic Era, Europe, Africa, and South 

America were approaching North America as the two 

great landmasses, Laurasia and Gondwana, collided. The 

ancient continent of Gondwana included Australia, 

Antarctica, Africa, South America, and India south of the 

Ganges River, plus smaller islands. Laurasia, located in 

the northern hemisphere, is the hypothetical continent 

that contained the present northern continents. These 

collectively formed the supercontinent Pangaea which 

was centered on the equator. 

What happened geologically in the Ordovician Period 

(438- 505 Ma) and the Silurian Period (408- 438 Ma) in 

southwestern Colorado and southeastern Utah remains a 

mystery because no Ordovician rocks or Silurian rocks 

are present. The end of the Ordovician Period (438 Ma) 

is marked by one of the five most extensive mass 

extinctions of all time (see Figure 19). The other four 

occurred at the end of the Devonian Period, the end of 

the Permian Period, at the close of the Triassic, and of 

course, at the Cretaceous – Tertiary boundary. 

By the beginning of the Devonian Period, the seas that 

had covered most of the continent had receded, or 

regressed, and the shoreline was far to the west. Tidal 

flats extended from western Colorado to central Utah. 

However, this quiet scene suddenly changed. 

The first pulses of the Antler Orogeny in the west and the 

Acadian Orogeny in the east (part of the Appalachian 

Orogeny) began to be felt as landmasses accreted onto 

both the western and eastern borders of North America. 

To the west of Colorado, a subduction zone formed. As 

lithospheric plates collided against one another, their 

rocks were bent, folded, and thrust- faulted into a northsouth trending mountain range stretching from Nevada 

to Canada. The Roberts Mountains Thrust marks the 

easternmost thrust sheets generated by the Antler 

Orogeny (figure 12). 

By the end of the Devonian, great inland seas again 

covered the continent, and a sea inundated the area 

between the western mountains and Colorado (Johnson 

et al., 1991). A marine carbonate platform extended into 

the Four- Corners area from the west. The 

Uncompahgre Arch, a feature that would eventually 

reemerge in the Pennsylvanian as part of the Ancestral 

Rocky Mountains, bordered the Four- Corners area to 

the northeast, and the broad Defiance Uplift lay to the 

southwest in New Mexico (Beus, 1980). 

As the highlands to the west were thrust above sea level 

at the beginning of the Mississippian Period, southwest 

Colorado still lay about 5o

 south of the equator. The 

warm marine water gave rise to extensive deposits of 

carbonate rocks (figure 13). Limestone, and dolomitic 

mudstones deposited in the lowermost Mississippian 

Period reflect deposition in intertidal to restricted 

subtidal environments as the transgressive sea advanced 

from the west (De Voto, 1980A; Poole and Sandberg, 

1991). The structural effects of compression on the 

western margin, however, could be felt as far inland as 

southwestern Colorado where local uplifts caused local 

regression and erosion. Aggressive tectonism in the 

Pennsylvanian Period built mountains (the Ancestral 

Rocky Mountains) in Colorado with as much as 3,000 m 

(10,000 ft) of relief (De Voto, 1980B). They supplied 

sediment to the Hovenweep area. 

With increasing southwest to northeast- directed 

compression, a northwest- southeast trending, shallow, 

subsiding trough called the Paradox Basin formed across 

the Four- Corners area (figure 14) (Stone, 1986). Periodic 

marine incursions from the south flooded the Paradox 

Basin and record a history of marine transgression into 

the area. As the water evaporated, salt deposits 

(evaporites) formed. By Late Pennsylvanian time, the 

Paradox Basin had filled with evaporite deposits and the 

shoaling that developed eliminated any barriers to 

circulation. Near- normal marine conditions returned to 

the area, depositing marine carbonates (Rueger, 1996). 
 NPS Geologic Resources Division 22 

The Permian was a time of worldwide changing 

environments. In the area of Hovenweep, broad 

lowlands bordered an ocean to the west (Baars, 2000). 

To the east and northeast, however, the peaks of the 

Uncompahgre Mountains bordered the lowland. 

The close of the Permian also brought the third, and 

most severe, major mass extinction of geologic time. The 

most recent hypothesis on the Permian event suggests 

that a comet, about 6- 13 km (4- 8 mi) in diameter, 

slammed into the earth (Becker et al., 2001). The 

resulting atmospheric disturbance plunged the earth into 

an cooling trend with downpours of acid rain. 

Thousands of species of insects, reptiles, and amphibians 

died on land while in the oceans, coral formations 

vanished, as did snails, urchins, sea lilies, some fish, and 

the once- prolific trilobites. The catastrophe wiped out 

300 million years of history. 

In the Early Triassic (240 to 245 Ma), volcanic activity 

decreased on the western margin of the supercontinent 

(Christiansen et al., 1994). The depositional 

environments in the Early Triassic represent a transition 

from marine and marginal marine environments in 

western Utah and Nevada to terrestrial (above sea level) 

environments in western Colorado. Throughout the 

Early Triassic the region around Hovenweep National 

Monument remained above sea level and red beds were 

deposited over the area. The red beds of the Lower 

Triassic, Moenkopi Formation were deposited in fluvial, 

mudflat, sabkha, and shallow marine environments 

(figure 15) (Stewart et al., 1972A; Christiansen et al., 1994; 

Doelling, 2000; Huntoon et al., 2000). 

The geologic history of the Middle Triassic remains a 

mystery in southwestern Colorado and Utah. No rocks 

that span this time range from 235- 240 Ma have been 

preserved. The Upper Triassic is a different story. 

Continental rocks of the Western Interior form a 

complex assemblage of alluvial (river debris), marsh, 

lacustrine (lake), playa (dried lake), and eolian (wind) 

deposits (Stewart et al., 1972B). Throughout the region, 

layers of bentonite (montmorillinite clays) formed from 

the alteration of volcanic ash, are interlayered with the 

clastic sediments. The bentonite layers indicate a period 

of renewed volcanism to the west (Christiansen et al., 

1994). As Pangaea began to break apart in the latest 

Triassic and earliest Jurassic, the monsoonal climate 

changed. The Western Interior of North America was 

slowly rotating into a position farther north of the 

equator. Soon, the Colorado Plateau was to become a 

Sahara. 

Extensive eolian sand seas, called ergs, blew across the 

Colorado Plateau during the Lower Jurassic (figure 16). 

The region was located about 18o

 north latitude at the 

beginning of the Jurassic and about 30- 35o

 north latitude 

at the end of the Jurassic (Kocurek and Dott, 1983; 

Peterson, 1994). 

This is the latitude of the trade wind belt. Most modern 

hot deserts of the world occur within the trade wind belt 

and during the Jurassic, the climate of the Colorado 

Plateau appears similar to the modern Western Sahara. 

The western edge of the continent was marked by a 

continental- margin magmatic arc, a product of 

subduction processes that began in the Triassic (Dubiel, 

1994) and reached its maximum development in the 

Cretaceous. At the beginning of the Middle Jurassic 

Period, the western Elko highlands emerged to the west 

of the Utah- Idaho trough. The highlands record an 

irregular, pulsed orogeny (Peterson, 1994). 

Middle Jurassic strata on the Colorado Plateau represent 

a complex interfingering of marine and nonmarine 

environments. The sediments were deposited during 

five major transgressive- regressive cycles (Peterson, 

1994). A picture emerges of broad tidal flats marginal to a 

shallow sea that lay to the west (Wright et al., 1962). The 

sea encroached into west- central Utah from the north 

and lay in the Utah- Idaho trough bordered to the west 

by the Elko Highlands. 

As plate tectonic activity increased at the end of the 

Middle Jurassic and beginning of the Late Jurassic (about 

157 Ma), a major transgression of the inland seaway 

forever destroyed the vast eolian sand seas that once 

covered the Colorado Plateau (Kocurek and Dott, 1983). 

Tidal flats covered the area as marine environments 

pushed south. The extensive Upper Jurassic, Morrison 

Formation was deposited across the continental Western 

United States (figure 17). Morrison depositional 

environments were quite varied. Sediments were 

deposited in mudflats, overbank floodplains, stream 

channels, small eolian sand fields, and scattered lakes 

and ponds (Peterson, 1994). 

During the Jurassic, the subducting oceanic slab that was 

sliding eastward beneath the continental lithosphere 

probably changed its angle of descent and became 

steeper. This change caused the volcanic arc to develop 

farther to the west near the present- day border of 

California and Nevada. The late Jurassic and earliest 

Cretaceous magmatic activity associated with the 

volcanic arc is called the Nevadan orogeny. Volcanic ash 

was spread across the Colorado Plateau. The Nevadan 

Orogeny evolved into the late Cretaceous Sevier 

Orogeny as the rate of lithospheric plate movement 

increased. 

The Sevier Orogeny formed a roughly north- south 

trending thrust belt that is well defined in present- day 

southern Nevada, central Utah, and western Montana 

(figure 18). A series of eastward- directed overthrusts 

carried upper Precambrian and lower Paleozoic 

sedimentary rocks over upper Paleozoic and lower 

Mesozoic rocks (Stewart, 1980). Today, the eastward 

limit of Sevier thrusting is exposed in the jagged peaks of 

the north- south trending Wasatch Range.
 HOVE Geologic Resource Evaluation Report 23

As the mountains rose in the west and the roughly 

north- south foreland trough expanded, the Gulf of 

Mexico separating North and South America continued 

to rift open in the south, and marine water began to spill 

into the basin. At the same time, marine water began to 

transgress from the Arctic region. 

The sea advanced, retreated, and readvanced many times 

during the Cretaceous until the most extensive interior 

seaway ever to cover the continent drowned much of 

western North America. 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). During periods of 

maximum transgression, the width of the basin was 1600 

km (1,000 mi). The basin was relatively unrestricted at 

either terminus (Kauffman, 1977). 

In the Four Corners region, the advances and retreats of 

the Cretaceous shoreline created a myriad of 

environments including incised river valley systems, 

estuaries, coal swamps, lagoons, delta systems, beaches, 

and offshore marine deposits. The interfingering of 

these environments is very complex, and the sedimentary 

rocks formed from the sediments include a variety of 

formations that have been grouped together into the 

Dakota Formation in western Colorado and eastern Utah 

(figure 22) and the Dakota Group in eastern Colorado. 

The coarse conglomeratic sandstones, crossstratification, petrified wood fragments, and erosional 

topography of the lower part of the Dakota Sandstone in 

the Hovenweep area suggests that the sediments were 

deposited by fluvial processes in paleovalleys incised into 

the underlying strata (Ekren and Houser, 1965; Condon, 

1991; Elder and Kirkland, 1994). 

At the beginning of Late Cretaceous time, the interior 

seaway had advanced to cover the eastern third of the 

Colorado Plateau. Gradually, as sea level rose, the soft, 

fissile, sparsely fossiliferous, dark- gray shale of the 

Mancos Shale was deposited in the deepening basin 

above the Dakota Sandstone. 

Tertiary deposits are not exposed in the Hovenweep 

National Monument area, but a brief history of events 

affecting the Colorado Plateau region is described here 

for completeness. At the end of the Cretaceous, the 

tectonic plates were actively jockeying for position on 

the western margin of the continent. Plutons were being 

emplaced beneath the Sierra Nevada, and for the first 

time, granitic plutons were being emplaced in a 

southwest- northeast trend from southwestern Colorado 

to north- central Colorado (Christiansen et al., 1994). 

The rearrangement of the tectonic plates gave rise to the 

Laramide Orogeny, the mountain- building episode that 

began the development of the modern Rocky 

Mountains. 

The Laramide Orogeny began about 66 to 70 million 

years ago, in the late Cretaceous, and continued 

intermittently until about 35- 50 million years ago. 

The Laramide event transformed the extensive basin of 

the Cretaceous Interior Seaway into smaller interior 

basins bordered by high arches (anticlines and synclines 

on the scale of miles). However, the Colorado Plateau 

region appears to have reacted as a single block to the 

crustal forces that buckled the rest of the central Rocky 

Mountains. The sedimentary strata on the Colorado 

Plateau was primarily warped into broad anticlinal and 

synclinal folds and great monoclines with very little 

brittle faulting (Dickinson and Snyder, 1978; Chapin and 

Cather, 1983; Hamilton, 1988; Erslev, 1993). 

Then, from about 26- 35 Ma, in the Oligocene epoch, 

volcanic activity erupted across Utah. The laccoliths that 

formed the Henry Mountains, La Sal Mountains, and 

Abajo Mountains were emplaced during mid- Tertiary 

volcanism that gave rise to the extensive San Juan 

volcanic field in Colorado. A period of volcanic 

quiescence followed from about 16 to 19 Ma. During this 

time, the western United States underwent a radical 

tectonic transformation wherein the compressional 

regime that had existed for millions of years became an 

extensional regime. As the crust was extended, the 

surface was broken into the basin- and- range, blockfaulted topography we see today in western Utah and 

Nevada. 

Block faulting and volcanism, however, were secondary 

to the uplift of the Colorado Plateau that occurred 

between 5 and 10 Ma (Hintze, 1988). The entrenchment 

of the Colorado River and its tributaries occurred at this 

time. Tertiary sediments are missing from Hovenweep, 

but extensional faulting and basaltic volcanism in the 

western United States have continued into the present. 

Two or three million years ago, early in the Quaternary, a 

broad uplift of the entire region initiated another period 

of active erosion. During the cooler, more humid 

climates of Pleistocene glaciation, streams cut headward 

into canyons, developing the drainage pattern seen today 

on the Colorado Plateau. Meltwater from glaciers 

brought more gravel deposits into the area. Wind from 

the southwest brought silt onto the Mesa Verde that 

developed into the rich, fertile soil exploited by the 

Anasazi. 

During Pleistocene glaciation (1.6 Ma to 10,000 years 

ago), locally on the Colorado Plateau, glaciers formed at 

elevations below 1,828 m (6,000 ft) (Jim Johnson, Mesa 

State College, retired, personal communication, 2001). 

Definitive evidence of glaciation is difficult to find on the 

plateaus. Unlike glacial moraines contained in alpine 

valleys such as those along the Front Range, the moraines 

on the plateaus do not form distinct patterns. In the 

West Mancos region, west of Hovenweep National 

Monument in southwestern Colorado – southeastern 

Utah, glaciers flowing from the La Plata Mountains 

reached an elevation of at least 2,620 m (8,600 ft) above 

sea level, but the maximum extent is questionable (Jim 

Johnson, personal communication, 2001). 
 NPS Geologic Resources Division 24 

Figure 12: Distribution of lithofacies during the Upper Devonian, Frasnian stage of western United States. The red line is the 

strontium isotope line wherein 87Sr/86Sr = 0.706 and is interpreted to represent the break between continental and oceanic crust. 

HOVE: Hovenweep National Monument. Modified from Johnson et al., 1991. 
 HOVE Geologic Resource Evaluation Report 25

Figure 13: Lithofacies map of the Lower Mississippian Period, Kinderhookian stage of the western United States. While the lithofacies 

are complex in the foreland basin adjacent to the Antler orogenic highland, a broad carbonate platform developed to the east. Marine 

water breached the Transcontinental Arch through the Paleozoic Strait. HOVE: Hovenweep National Monument. Any Mississippian 

rocks that were deposited on the transcontinental Arch or ancestral Uncompahgre highland during this time have been eroded. 

Modified from Poole and Sandberg, 1991. 
 NPS Geologic Resources Division 26 

Figure 14: Map of the Paradox Basin. Heavy line represents the approximate limits of halite in the Middle Pennsylvanian Paradox 

Formation. Shaded area is the location of the Uncompahgre trough on the west-southwest border of the Uncompahgre uplift. HOVE: 

Hovenweep National Monument headquarters. Modified from Rueger (1996). 
 HOVE Geologic Resource Evaluation Report 27

Figure 15: Paleogeographic map of the Lower Triassic, Moenkopi Formation during the second transgressive episode of the Early 

Triassic. HOVE: Hovenweep National Monument. Modified from Dubiel, 1994. 
 NPS Geologic Resources Division 28 

Figure 16: Paleogeographic map of the Lower Jurassic Period. Thick arrows indicate eolian transport of sand. Thin arrows indicate 

fluvial transport of sediments. Inverted “Vs” indicate the location of the volcanic arc. Solid triangles indicate the location of the 

subduction zone with the triangles on the overriding, upper lithospheric plate. HOVE: Hovenweep National Monument. Modified from 

Lawton (1994). 
 HOVE Geologic Resource Evaluation Report 29

Figure 17: Upper Jurassic Period paleogeography. Thin arrows indicate fluvial dispersal. Thick arrows indicate wind directions. 

Sawteeth indicate the location of the subduction zone with the teeth on the overriding lithospheric plate. A marine environment 

possibly covered continental environments to the east. The alluvial plain expanded to the east with time. Modified from Lawton 

(1994). 
 NPS Geologic Resources Division 30 

Figure 18: Location of Hovenweep National Monument (HOVE) on a tectonic map of the Laramide foreland. The map illustrates the 

anastamosing nature of the basement-cored arches (regional-scale anticlines) and the spatial relationships with the adjacent thrust 

belt, Colorado Plateau, and North American craton. From Gregson and Chure, 2000. 
 HOVE Geologic Resource Evaluation Report 31

Figure 19: Geologic Time Scale. Red lines indicate major unconformities between eras. Included are major events in life history and 

tectonic events occurring North American continent. Absolute ages shown are in millions of years and are from the United States 

Geological Survey (USGS) time scale found at: http://geology.wr.usgs.gov/docs/usgsnps/gtime/timescale.html.
 NPS Geologic Resources Division 32 

References 

The following is a list of scientific literature references for the geologic resources 

evaluation of Hovenweep National Monument, many of the authors are cited in this 

report, others are included for general reference purposes. 

Aubrey, William M., 1991, Geologic framework and 

stratigraphy of Cretaceous and Tertiary rocks of the 

southern Ute Indian Reservation, southwestern 

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254 p. 

Baars, Donald L, 1995, Navajo Country: University of 

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Impact event at the Permian- Triassic boundary: 

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United States: Rocky Mountain Section, SEPM 

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

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Porter, eds., Colorado Geology: Rocky Mountain 

Association of Geologists, p. 57- 70. 
 HOVE Geologic Resource Evaluation Report 33

De Voto, R. H., 1980B, Pennsylvanian stratigraphy and 

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 NPS Geologic Resources Division 34 

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 HOVE Geologic Resource Evaluation Report 35

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 NPS Geologic Resources Division 36 

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 HOVE Geologic Resource Evaluation Report 37

Appendix A: Geologic Map Graphic 

This image provides a preview or "snapshot" of the digital geologic map for Hovenweep 

National Monument which can be found on the included CD. 

The original map digitized by NPS staff to create this product was: Poole, A., 2000, Geologic map of Hovenweep National Monument 

and the Surrounding Area, Colorado, NPS, unpublished, 1:24000 scale. For a detailed digital geologic map and cross sections, see 

included CD. 
 NPS Geologic Resources Division 38 

Appendix B: Southeast Utah Group Scoping Summary 

The following excerpts are from the GRE Workshop Summary for the NPS Southeast 

Utah Group (SEUG) and provide regional geologic information. Although included in 

this group, a separate scoping meeting was held for Hovenweep National Monument 

September 5- 6, 2000. This summary is included as Appendix C. Both are historical 

documents and as such contact information and web addresses referred to herein may 

be outdated. 

Executive Summary 

An inventory workshop was held for national park 

service units in the Southeast Utah Group (Arches NP, 

Canyonlands NP, Hovenweep NM, and Natural Bridges 

NM) from May 24- 27, 1999 to view and discuss the 

geologic resources, to address the status of geologic 

mapping by the Utah Geological Survey (UGS) 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), 

Southeast Utah Group NPS staff (interpretation, natural 

resources, deputy superintendents), UGS, United States 

Geological Survey (USGS), and Utah Geological 

Association (UGA) were present for the two day 

workshop. 

Monday May 24th involved a field trip to Natural Bridges 

NM (NABR) led by Red Rocks College geologist Jack 

Stanesco with additions from Christine Turner and Pete 

Peterson (both of the USGS). 

Tuesday May 25th involved a field trip to Canyonlands 

NP (CANY) led by USGS geologist George Billingsley, 

again with additions from Christine Turner and Pete 

Peterson also of the USGS. 

Wednesday May 26th involved a field trip to Arches NP 

(ARCH) led by UGS geologist Hellmut Doelling with 

additions from Grant Willis (UGS) and Vince Santucci 

(NPS- GRD). 

An on- line slide show of the highlights of these field 

trips can be found at 

http://www.nature.nps.gov/grd/geology/gri/ut/seug/field

_trip_seug 

 

Thursday May 27th 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 Evaluation (GRE) for 

Colorado and Utah. Round table discussions involving 

geologic issues for the Southeast Utah Group 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 of Geologic Resources Evaluation 

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. 

For a recap on this process, go to: 

http://www.nature.nps.gov/grd/geology/gri/blca_cure/ 

and view the various files in the directory. 

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 an introduction 

to the NPS GRD group. 

Interpretation 

The GRE 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. 

Along the lines of interpretation of geology for the 

SEUG, it was suggested that they consider hiring a fulltime geologist to be on staff to evaluate research 

proposals and generally assist all interpretive areas 
 HOVE Geologic Resource Evaluation Report 39

within the SEUG to find out what issues should be 

addressed. A geologist could add greatly to NABR, 

CANY, and ARCH because the primary theme of these 

parks is geologic; there would be no bridges, arches, or 

canyon (lands) without the underlying influence of 

geology and geologic processes upon this part of the 

world. A geologist would also certainly be active in 

establishing the most effective wayside exhibits aimed at 

informing the public about the geologic wonders of the 

area. A geologist can certainly assist in the presentation 

and interpretation of paleontologic resources and issues 

also. 

Such a position could act as a liaison among various tour 

groups, researchers, field camps and professional 

organizations that visit the area because of the 

spectacular geology. Geologic hazards would also be 

able to be more fully understood. Obviously, effective 

communication skills are a highly desirable quality for 

any applicant. 

In the absence of such a position, the GRD is most 

willing to assist the SEUG in any geologic matters and 

issues should they desire. Please contact Bruce Heise or 

Tim Connors to discuss further matters regarding 

geologic resources. 

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 GRE 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). Authors for SEUG parks are as follows: 

Arches NP: Hellmut Doelling (UGS) 

Canyonlands NP: Donald Baars 

Natural Bridges NM: Jackie Huntoon, Russell Dubiel, 

Jack Stanesco 

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. Park authors are strongly 

encouraged to get with NPS staff to make sure that any 

trail logs do follow maintained trails and do not take 

visitors into unauthorized areas, or places where 

resources are fragile and would be disturbed by 

increased visitation (i.e. areas with crytptogamic soils). 

The photo glossary will describe certain geologic features 

(i.e. what is crossbedding?). These will also be available 

as web- downloadable 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 

GRE. 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: 

Arches NP, Canyonlands NP, Dead Horse Point State 

Park (SP) 

Antelope Island SP and Wasatch Mountain SP 

Southeast Utah Group NP, Cedar Breaks NM, Snow 

Canyon SP and Quail Creek SP 

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. 

Disturbed Lands 

GRD's John Burghardt has done work in Lathrop 

Canyon on reclaiming abandoned mineral lands (aml). 

His reports should be studied as a significant source of 

data for this area to determine if additional work needs 

to be performed. Dave Steensen (GRD) heads the AML 

program and can also be contacted.

Paleontological Resources 

The field trip at Arches NP provided glimpses into the 

paleontological resources (dinosaur bones) near Delicate 
 NPS Geologic Resources Division 40 

Arch. It has been suggested to keep this location low 

profile to minimize disturbances and potential theft or 

vandalism. 

During the scoping session, the importance of a 

paleontological resource inventory for the Cedar 

Mountain and Morrison Formations near the Dalton 

Wells Quarry was discussed as being a priority. The 

important resources are likely to be dinosaur bones. A 

staff geologist or paleontologist would surely be useful 

for this purpose 

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

Park" and detailing findings of resources within the park. 

Plants, invertebrates, and vertebrate tracksites are among 

the recognized paleontological resources within the 

Southeast Utah Group area parks. 

Similar surveys have been done for Yellowstone and 

Death Valley NPs 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 Southeast Utah Group 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 Geologic Mapping Efforts for the SEUG 

Status of Existing Maps 

It should be noted that the following paper geologic 

maps exist: 

Arches NP ("Geologic Map of Arches National Park and 

vicinity, Grand County, Utah" by Hellmut H. Doelling, 

1985) at 1:50,000. The area was mapped at 1:24,000 scale, 

but compiled at 1:50,000 scale. 

Canyonlands NP ("Geologic Map of Canyonlands 

National Park and Vicinity, Utah" by George Billingsley, 

Peter Huntoon, and William J. Breed, 1982) at 1:62,500 

Canyonlands NP ("Bedrock Geologic Map of Upheaval 

Dome, Canyonlands NP, Utah" by Gene Shoemaker, 

Herkenhoff and Kriens, 1997); scale unknown. 

George Billingsley noted that when he worked on the 

Canyonlands map, he mostly compiled previous 

material. He thought several additions to the Quaternary 

deposits and the placement of joints/fractures on the 

maps would improve the quality of the 1982 Canyonlands 

map. There are also some issues regarding assignment of 

the Page Sandstone, and the controversy of the Dewey 

Bridge Member of the Entrada versus the Carmel 

Formation being within the map area. He thinks 

eventually, the entire area should be compiled at 1:24,000 

to better enhance features and add to resource 

management. 

Jackie Huntoon has told Bruce Heise that she is working 

on a digital coverage for Natural Bridges, but needs the 

hypsography (contour lines) to complete her work. 

Desired quadrangles that NRID has this coverage for are 

the following: 

The Cheesebox 

Woodenshoe Buttes 

Kane Gulch 

It is not sure if the coverage exists for the Moss Back 

Butte quadrangle; Joe Gregson will look into it. 

Digitized Maps 

The 1985 Arches map has been digitized into an ArcInfo 

coverage by SEUG staff. The attribute quality is 

unknown however, and will be researched. NPS- GRE 

folks will work with SEUG GIS Specialist Gery 

Wakefield to learn more about this coverage 

The 1982 Canyonlands map is not known to have been 

digitized at this point and hopefully can be done by the 

SEUG GIS staff. George Billingsley says that the 

Canyonlands Natural History Association has the 

original line work and mylars; Diane Allen said she will 

contact them to see if they still have this work. 

The 1997 Upheaval Dome map is digitized as an ArcInfo 

coverage and a copy was given to Craig Hauke (CANY) 

from George Billingsley. It also contains cross sections 

and a report. A website exists for this work at: 

http://www.seismo.unr.edu/ftp/pub/louie/dome/98seism

o/index.html. 

UGS Mapping Activities in SEUG area 

Currently, the UGS is mapping in Utah at three different 

scales: 
 HOVE Geologic Resource Evaluation Report 41

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 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 Southeast Utah Group 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. 

Grant Willis talked about the status of UGS mapping 

activities within the Southeast Utah Group area (see 

Appendix C for reviewing specific index maps for each 

park). 

30 x 60 sheets (at 1:100,000) for the area include the La 

Sal (greater Canyonlands area) and Moab (Arches NP) 

sheets, which are currently in progress (paper and digital 

format). 

Other Sources of Natural Resources Data for the SEUG 

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 all parks in 

the Southeast Utah Group. Visit the website at: 

http://165.83.36.151/biblios/geobib.nsf; user id is "geobib 

read", password is "anybody". 

SEUG GIS specialist showed a digitized version of 

Hellmut Doelling's 1985 map as and ArcInfo coverage; 

attribution needs to be checked; other coverage's should 

be sought that may exist from the previous GIS specialist 

GRD has several entries regarding abandoned mineral 

land (AML) sites in their database that should be 

checked for data validity and compared with park 

records; John Burghardt (GRD) should be contacted 

regarding this 

The Arches NP visitor center sells a publication that has 

an inventory of all the arches of Arches 

The UGS has compiled a CD- ROM with well locations, 

pipelines, etc. for the state of Utah; GRD should obtain a 

copy of this. Parks may also desire copies too. 

Geologic Hazards 

There are numerous issues related to geologic hazards in 

and around the Southeast Utah Group parks. Below is a 

brief list of some mentioned during the scoping session: 

Landslide and rockfall potential along all roads that 

occasionally cause road closures; of special note was the 

problem with the main road in Arches, just above the 

visitor center 

Landscape Arch (ARCH) collapsed in a few places 

several years ago and was recorded by a tourist 

Swelling soils associated with bentonitic shale's of the 

Chinle, Morrison, and Mancos formations 

Radon potential associated with mine closures 

Earthquake potential along the Moab Fault 

Potential Research Topics for Southeast Utah Group NP 

A list of potential research topics includes studies of the 

following: 

What are the connections between gypsiferous rocks and 

cryptobiotic soils/crusts?; why were the crust healthier 

on the gypsum- bearing rocks? 

How long will Delicate Arch stand? 

Engineering studies to determine hazards to visitors; use 

strain meter 

Use High resolution GPS to detect moving, swelling, and 

collapse in areas of the parks 

Rock color studies 

Subsurface seismic work for voids in the Needles around 

synclines and salt dome structures 

Locate real unconformity between Entrada Moab 

Tongue and abutting formations
 NPS Geologic Resources Division 42 

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 

Southeast Utah Group 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). 

Consider the possibility of hiring a full- time geologist to 

handle geologic issues for the SEUG; in the absence of 

this consult with GRD for assistance in geologic matters 

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 GRE 

Have authors prepare logs that are "sensitive" to delicate 

areas in the park (i.e. where less user impact is desired) 

Paleontological Resources 

For now, try to minimize location disclosure of 

vertebrate sites 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 especially in regard to the 

Dalton Wells area 

Locate collections taken from the park residing in 

outside repositories 

Geologic Mapping 

Attempt to complete digital coverage for the entire 

SEUG area from existing maps (figure 12) 

Locate already existing digital coverage's (like that of 

Doelling's 1985 Arches map) 

Work closely with UGS to finish paper and digital 

coverage of SEUG area where maps are lacking 

Work with cooperators (NABR- Jackie Huntoon) to 

ensure there work could be incorporated into the master 

plan of the GRE 

Natural Resource Data Sources 

Examine GRD databases for AML and disturbed lands 

for data validity 

Attempt to locate other digital coverage's from the 

previous SEUG GIS specialist (Eric) for Gery Wakefield's 

(current SEUG GIS specialist) inventory 

Miscellaneous 

Review proposed research topics for future studies 

within Southeast Utah Group NP 

Promote sensitivity to delicate resources (crusts, etc.) to 

researchers, and visiting park groups 
 HOVE Geologic Resource Evaluation Report 43

List of Scoping Meeting attendees with contact information 

NAME AFFILIATION PHONE E-MAIL 

Joe Gregson NPS, Natural Resources Information 

Division (970) 225-3559 Joe_Gregson@nps.gov 

Tim Connors NPS, Geologic Resources Division (303) 969-2093 Tim_Connors@nps.gov 

Bruce Heise NPS, Geologic Resources Division (303) 969-2017 Bruce_Heise@nps.gov 

Christine Turner USGS (303) 236-1561 Cturner@usgs.gov 

Fred Peterson USGS (303) 236-1546 Fpeterson@usgs.gov 

Jack Stanesco Red Rocks CC (303) 914-6290 Jack.Stanesco@rrcc.cccoes.edu 

Craig Hauke NPS, CANY (435) 259-3911 

ext. 2132 Craig_hauke@nps.gov 

Grant Willis Utah Geological Survey (801) 537-3355 Nrugs.gwillis@state.ut.us 

George Billingsley USGS-Flagstaff, AZ (520) 556-7198 Gbillingsley@usgs.gov 

Vince Santucci NPS, Geologic Resources Division (307) 877-4455 Vince_Santucci@nps.gov 

Jim Dougan NPS, NABR (435) 692-1234 Jim_Dougan@nps.gov 

Al Echevarria Red Rocks CC (303) 985-5996 Ale44@juno.com 

Dave Wood NPS, CANY (435) 259-3911 

ext. 2133 Dave_Wood@nps.gov 

Traci Kolc NPS, CANY (435) 259-4712 

ext. 18 Traci_Kolc@nps.gov 

Margaret Boettcher NPS, ARCH SCA (435) 259-1963 Margaret_arches@hotmail.com 

Clay Parcels NPS, ARCH (435) 259-8161 

ext. 245 Clay_Parcels@nps.gov 

Alicia Lafever NPS, ARCH (435) 259-8161 

ext. 242 Alicia_Lafever@nps.gov 

Adrienne Gaughan NPS, ARCH (435) 259-8161 

ext. 286 Adrienne_Gaughan@nps.gov 

Shawn Duffy NPS, ARCH (435) 259-7223 Shawn_Duffy@nps.gov 

Murray Shoemaker NPS, ARCH (435) 259-8161 

ext. 244 Murray_Shoemaker@nps.gov 

Helmut Doelling UGS (435) 835-3652 None 

Doug Sprinkel UGS / UGA (801) 782-3398 Sprinkel@vii.com 

Jim Webster NPS, ARCH (435) 259-8161 

ext. 220 Jim_Webster@nps.gov 

Gery Wakefield NPS, SEUG GIS coordinator (435) 259-3911 

ext. 2180 Gery_Wakefield@nps.gov 

Phil Brueck NPS, SEUG (435) 259-3911 

ext. 2102 Phil_Brueck@nps.gov 

Bruce Rodgers NPS, SEUG (435) 259-3911 

ext. 2130 Bruce_Rodgers@nps.gov 

Diane Allen NPS, ARCH (435) 259-8161 Diane_Allen@nps.gov 

Paul Henderson NPS, SEUG (435) 259-3911 

ext. 2140 Paul_Henderson@nps.gov 
 NPS Geologic Resources Division 44 

Figure B.1: Shows map coverage of Hovenweep National Monument at the scale of 1:24,000 and larger. From GRE Scoping Report. 
 HOVE Geologic Resource Evaluation Report 45

Appendix C: Hovenweep NM Scoping Summary 

The following is a summary of the scoping meeting held at Hovenweep National 

Monument September 5- 6, 2000. This section reflects the views of the geologic inventory 

and mapping status of the monument at the time of scoping.

Summary 

A geologic resources inventory scoping meeting was 

conducted on September 5- 6, 2000 to discuss how to 

achieve the production of digital geologic maps for 

Hovenweep NM (HOVE) units (Square Tower, Holly, 

Horseshoe Hackberry, Cutthroat, Goodman Point and 

Cajon). Attendees included the HOVE superintendent, 

Geologic Resources Division, and GIS staff from MEVE 

and the Southeast Utah Group. 

A geologic resources inventory workshop was held for 

Hovenweep NM (HOVE) on September 5- 6, 2000 to 

view and discuss the park’s geologic resources, to 

address the status of geologic mapping 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), NPS 

Hovenweep NM, Mesa Verde NP and Southeast Utah 

Group were present for the two- day workshop. 

Day one involved a half- day scoping session to present 

overviews of the NPS Inventory and Monitoring (I&M) 

program, the Geologic Resources Division, and the on 

going Geologic Resources Inventory (GRI) for Colorado 

and Utah. 

Day two involved a half- day field trip to view the 

geology of the Hovenweep Square Tower Unit led by 

Palma Wilson. 

Round table discussions involving geologic issues for 

Hovenweep NM included interpretation, paleontologic 

resources, and the status of geologic mapping efforts, 

sources of available data, geologic hazards, and action 

items generated from this meeting. Brief summaries 

follow. 

Attendees: 

Palma Wilson (HOVE Superintendent) 

Tim Connors (Geologic Resources Division- GRI_ 

Steve Fryer (Natural Resources Information Division) 

Anne Poole (MEVE- GIS) 

Allan Loy (MEVE- GIS) 

Gery Wakefield (SEUG- GIS) 

Items of discussion included the following: 

ProCite database: 

Palma Wilson was not aware of a ProCite database for 

HOVE, but others thought that it could be found in the 

Colorado Plateau 1994 data that Allan Loy mentioned; 

needs follow- up. 

Geologic Mapping: 

The new "Canyon of the Ancients NM" may have new 

geologic mapping being initiated by the BLM; needs 

follow- up with local BLM to see if they are producing 

digital geologic maps of the area and could merge with 

NPS GRI project. 

Anne Poole will be revising the 1950's vintage photogeologic maps of R.J. Hackman that were never "fieldtruthed" with field checks to the various HOVE units. 

Permission will need to be obtained from the 

superintendent of Canyons of the Ancients (Anasazi 

Heritage Center at 970- 882- 4811) for the Colorado 

portion, and from the BLM’s Monticello Office for the 

Utah portion (Kent Walters at 435- 587- 1500). 

Anne’s main concern is distinguishing the Jurassic 

Morrison Formation members from the overlying 

Cretaceous rocks (Burro Canyon and Dakota 

Sandstone), as she doesn't feel like an expert in that area. 

Tim Connors has contacted Pete Peterson (USGSDenver and Mesozoic geologist extraordinaire), who is 

amenable to working with Anne to give her a better grasp 

of the stratigraphy. He thought he would be in the area 

the first week of October and could meet with Anne at 

that time. More to come when Pete returns from field 

work. 

Anne estimated approximately six months to complete 

map products (digital finished product) for HOVE. 

USGS Map I- 629 (the Cortez quadrangle) has a scale of 

1:250,000 and does encompass all HOVE units, but its 

small scale has shortcomings that 1:24,000 scale mapping 

enhances. 

Digital Geologic Map coverage: 

Once the field geology is verified, Anne will be digitizing 

the entire quadrangles that encompass the HOVE units. 

She already has four of the quadrangles scanned, 

rectified and ready for digitization. The others will need 

to be obtained as topographic maps. 

The only units not covered under the Hackman Photogeologic maps are Goodman Point and Cutthroat. It was 

also suggested to map the Woods Canyon for continuity 

and for regional geologic implications. The Square 

Tower and Cajon units reside in Utah; all the rest are in 

Colorado. 
 NPS Geologic Resources Division 46 

Quadrangle HOVE unit 

Aneth 1 (aka. Ruin Point) Square Tower, Holly and Horseshoe Hackberry 

Aneth 7 (aka. Navajo Canyon) Cajon 

Negro Canyon Cutthroat Unit (approximately 14 acres) 

Arriola Goodman Point (1/4 section) 

Woods Canyon none 

Paleontology: 

Vince Santucci (NPS- FOBU) has indentified 

paleontological sites within the HOVE units, and needs 

consulted for this information. It was suggested that a 

paleontological survey, much like the one being 

conducted for ARCH, should be done for the HOVE 

units. 

Other GIS data: 

Allan Loy is interested in finding out if 10 meter DEM’s 

(digital elevation models) exist for the area; needs 

follow- up with NRID. It was suggested that Kerry Mich 

(Intermountain region GIS, Albuquerque) may have 

some information on this. 

Anne Poole is also interested in locating aerial 

photography used to map vegetation, as it could be 

useful in mapping the geology; needs follow- up (Mike 

Story - NRID ??) 

Palma Wilson is going to check with San Juan County on 

their soil mapping activities in the area; needs follow- up. 

Interpretation: 

 During the site visit to the Square Tower unit, Tim 

Connors suggested that a pamphlet be developed talking 

about the geology of HOVE along the trail, as the park 

has a strong geologic component as well as cultural. Tim 

will attempt to write something up for the park to use to 

interpret the importance of geology to the HOVE story. 

Miscellaneous: 

When Anne Poole comes to map, she will need to be in 

NPS uniform or have the accompaniment of an NPS 

ranger to avoid conflicts with locals and visitors. 

Anne is also interesed in seeing about the availability of 

park housing while she is mapping the area to cut down 

on travel time and such; needs follow- up. 

The Square Tower boulder foundation has been shown 

to be eroding and threatening the resource. A report was 

written on this problem and should be incorporated into 

a final geologic report on HOVE. Mary Griffitts served as 

a consultant on this project where the boulders were 

injected to slow the erosional process. GRD staff were 

given a copy of the report during the meeting. 

Water quality in the area is of concern because of the 

numerous seeps along geologic units. 
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. 

Hovenweep National Monument 

Geologic Resource Evaluation Report 

Natural Resource Report NPS/NRPC/GRD/NRR—2004/002 

NPS D-35, September 2004 

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 • Trista Thornberry-Ehrlich

Editing • Sid Covington 

Digital Map Production • Anne Poole 

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