Theodore Roosevelt National Park 

Geologic Resource Evaluation Report 

Natural Resource Report NPS/NRPC/GRD/NRR—2007/006 

National Park Service 

U.S. Department of the Interior 

Natural Resource Program Center 
THIS PAGE: 

The Little Missouri River flows near the Juniper Campground 

in the North Unit of Theodore Roosevelt NP, ND. 

ON THE COVER: 

View from the Oxbow Overlook Theodore Roosevelt NP, ND. 

Photos by: Dave Krueger 
Theodore Roosevelt National Park 

Geologic Resource Evaluation Report 

Natural Resource Report NPS/WASO/NRPC/GRD—2007/006 

Geologic Resources Division 

Natural Resource Program Center 

P.O. Box 25287 

Lakewood, Colorado 80225 

June 2007 

U.S. Department of the Interior 

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

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

management of natural resources, including the scientific community, the public, and the NPS 

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the information is scientifically credible, technically accurate, appropriately written for the 

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general, diverse audience, and may contain NPS policy considerations or address sensitive 

issues of management applicability. Examples of the diverse array of reports published in this 

series include vital signs monitoring plans; "how to" resource management papers; 

proceedings of resource management workshops or conferences; annual reports of resource 

programs or divisions of the Natural Resource Program Center; resource action plans; fact 

sheets; and regularly- published newsletters. 

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

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

Resource Evaluation Program website (http://www2.nature.nps.gov/geology/inventory/

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

Please cite this publication as: 

KellerLynn, K. 2007. Theodore Roosevelt National Park Geologic Resource Evaluation 

Report. Natural Resource Report NPS/NRPC/GRD/NRR—2007/006. National Park Service, 

Denver, Colorado. 

NPS D- 133, June 2007 
 THRO Geologic Resource Evaluation Report iii

Table of Contents 

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

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

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

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

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

Geologic Setting .........................................................................................................................................................2

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

Oil and Gas Development ..........................................................................................................................................6

Abandoned Mine Lands..............................................................................................................................................7

Coal Fires ...................................................................................................................................................................7

Coal Resources and Mining........................................................................................................................................8

Flooding and Fluvial Erosion ......................................................................................................................................9

Mass Wasting.............................................................................................................................................................9

Paleontological Resources .......................................................................................................................................10

Piping .......................................................................................................................................................................10

Swelling Soils and Bentonite ....................................................................................................................................11

Geologic Features and Processes............................................................................. 18

Concretions and Cap Rocks.....................................................................................................................................18

Glacial Erratics .........................................................................................................................................................18

Eolian Deposits.........................................................................................................................................................18

Oxbows ....................................................................................................................................................................18

Pediments ................................................................................................................................................................19

Sand and Gravel.......................................................................................................................................................19

Sandstone and Silcrete ............................................................................................................................................19

Sheetwash Erosion...................................................................................................................................................19

Terraces ...................................................................................................................................................................20

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

Map Unit Properties Table........................................................................................................................................24

Geologic History.......................................................................................................... 25

Pre-Paleocene..........................................................................................................................................................25

Paleocene ................................................................................................................................................................25

Post-Paleocene ........................................................................................................................................................26

Glossary....................................................................................................................... 28

References................................................................................................................... 30

Appendix A: Geologic Map Graphic .......................................................................... 32

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

List of Figures 

Figure 1. Location Map of Theodore Roosevelt National Park.......................................................................................3

Figure 2. Bison in the South Unit Crossing the Little Missouri River.. ............................................................................3

Figure 3. Physiographic Areas of the Great Plains.........................................................................................................4

Figure 4. Detailed maps of the North and South Units in Theodore Roosevelt National Park........................................5

Figure 5. Lignite. ..........................................................................................................................................................14

Figure 6. Clinker...........................................................................................................................................................14

Figure 7. Cap Rock.. ....................................................................................................................................................15

Figure 8. Little Missouri River.......................................................................................................................................15

Figure 9. Rotational Slump...........................................................................................................................................16

Figure 10. Petrified Stump.. .........................................................................................................................................16

Figure 11. Piping..........................................................................................................................................................17

Figure 12. Bentonitic Clay Overlook of the North Unit..................................................................................................17

Figure 13. View of Badlands from Oxbow Overlook.....................................................................................................21

Figure 14. Oxbow Overlook ........................................................................................................................................22

Figure 15. Shelter at Riverbend Overlook ....................................................................................................................22

Figure 16. Pre- and Post-Glacial Drainages of North Dakota.......................................................................................27

List of Tables 

Table 1. Geologic Time Scale ......................................................................................................................................11

Table 2. Potential Impacts of Surface Mining on Park Resources................................................................................12

Table 3. Flood Discharges for Little Missouri River and Tributaries in Theodore Roosevelt National Park..................12

Table 4. Fossils at Theodore Roosevelt National Park ................................................................................................13

Table 5. Factors Affecting the Stability of In Situ Paleontological Resources ..............................................................13
 THRO Geologic Resource Evaluation Report 1

Executive Summary 

This report accompanies the digital geologic map of Theodore Roosevelt National Park 

produced by staff of the Geologic Resource Evaluation Program. The report contains 

information relevant to resource management and scientific research. 

In addition to memorializing the life, times, and thinking 

of Theodore Roosevelt, park managers “conserve 

unimpaired the scenery and natural and cultural 

resources and facilitate scientific interests in Theodore 

Roosevelt National Park” (Theodore Roosevelt National 

Park, Statement for Management, November 1994). 

Because the park’s land management plan identifies oil 

and gas development adjacent to the park as the single 

greatest threat to park resources, this issue is discussed 

first. Other geologic resource issues that may require 

management attention follow alphabetically. 

• Oil and Gas Development—Energy resources in 

Theodore Roosevelt and the surrounding area include 

oil, gas, and lignite. While federal oil and gas leasing is 

prohibited in the park, oil and gas development 

adjacent to the park has a high potential to impact 

both cultural and natural resources, including air and 

water quality; wildlife and plants, particularly 

threatened and endangered species; natural quiet; 

scenic views; visitor experience, and dark night skies. 

Extensive air quality studies have occurred in the area 

under the auspices of the NPS Air Resources Division 

in the Natural Resource Program Center. 

• Abandoned Mine Lands—In 1999 park staff 

permanently closed two mine openings in the park. 

Closure has prevented local residents and visitors from 

entering the mine and exposing themselves to hazards 

such as methane, oxygen- deficient conditions, and 

rockfall. Periodic monitoring of these closures is 

warranted but no further mitigation is needed. No 

additional abandoned mine hazards are known in the 

park. 

• Coal Fires—Exposed coal beds are susceptible to 

ignition via grass fires, lightning strikes, and 

spontaneous combustion. Once ignited, coal fires may 

burn for many years. The Coal Vein Trail in the park 

highlights a fire that burned for 26 years (1951–1977). 

No coal beds are currently burning in the park. 

However, fire is a natural element in the regional 

ecosystem, and resource managers can anticipate 

future burns. 

• Coal Development— Under federal law coal mining is 

prohibited in Theodore Roosevelt National Park 

subject to “valid existing rights” (VER). Coal is a 

leasable commodity and since no coal leases exist in 

the park there are no VER. Coal resources in the park 

include lignite and clinker. Lignite is a low- rank coal 

with thick yet deeply buried beds immediately west of 

the park; mining these beds is uneconomic with 

present technologies. However, the potential remains 

for development of coal- bed methane from these beds 

outside the park. Burned coal beds—clinker—provide 

color to the landscape and contribute to the formation 

of North Dakota badlands. 

• Flooding and Fluvial Erosion—The Little Missouri 

River flows through the three units of the park. Park 

infrastructure and visitor- use facilities are located in 

the 100- year floodplain. In addition to flooding, 

channel migration and bank erosion may adversely 

affect facilities such as the Juniper, Cottonwood, and 

Squaw Creek campgrounds. 

• Mass Wasting—Primary hazards associated with mass 

wasting in the park consist of landslides and soil creep. 

Locally, landslides have been exacerbated by road 

construction in the park. All existing landslide deposits 

are capable of renewed activity, and other slopes, 

especially those in the North Unit containing the 

Sentinel Butte Formation, may be vulnerable to future 

movement. 

• Paleontological Resources—Petrified wood and 

freshwater mollusks in the Bullion Creek and Sentinel 

Butte formations are the most abundant fossils in the 

park. The increase in popularity of wilderness 

recreation over the last 20 years has resulted in greater 

access and concern for protecting fossils. The ability to 

manage and protect fossil resources is contingent 

upon an understanding of their geologic and 

geographic occurrence and distribution. NPS 

paleontologists have recently developed a monitoring 

plan for protecting in situ fossil resources, which may 

be applicable in the park. 

• Piping—Percolating water removes soluble or 

transportable earth materials, creating tunnels and 

small caves called “pipes.” Piping may result from 

natural or anthropogenic causes and is common in 

landscapes with rill erosion. In the park, the principal 

hazard associated with erosional pipes is collapse. 

• Bentonite—The characteristic “blue beds” of the 

Sentinel Butte Formation are composed of bentonite. 

When wetted, bentonite “swells,” expanding up to 16 

times in volume. The swelling (and shrinking) of this 

layer can cause structural damage to buildings, roads, 

and other infrastructure. Also, wet Sentinel Butte 

bentonite produces slippery, hazardous conditions 

cross- country and on roads and trails. 

Other distinctive features and processes in the park are 

concretions and cap rocks, eolian deposits, glacial 

erratics, oxbows, pediments, sand and gravel, sandstone 

and silcrete, sheetwash, and terraces. These are discussed 

in the “Features and Processes” section of this report. 
 NPS Geologic Resources Division 2 

Introduction 

This section briefly describes the National Park Service Geologic Resource Evaluation 

Program and the regional geologic setting of Theodore Roosevelt National Park. 

Purpose of the Geologic Resource Evaluation Program 

The Geologic Resource Evaluation (GRE) Program is 

one of 12 inventories funded under the NPS Natural 

Resource Challenge designed to enhance baseline 

information available to park managers. The program 

carries out the geologic component of the inventory 

effort from the development of digital geologic maps to 

providing park staff with a geologic report tailored to a 

park’s specific geologic resource issues. The Geologic 

Resources Division of the Natural Resource Program 

Center administers this program. The GRE team relies 

heavily on partnerships with the U.S. Geological Survey, 

Colorado State University, state surveys, and others in 

developing GRE products. 

The goal of the GRE Program is to increase 

understanding of the geologic processes at work in parks 

and provide sound geologic information for use in park 

decision making. Sound park stewardship relies on 

understanding natural resources and their role in the 

ecosystem. Geology is the foundation of park 

ecosystems. The compilation and use of natural resource 

information by park managers is called for in section 204 

of the National Parks Omnibus Management Act of 1998 

and in NPS- 75, Natural Resources Inventory and 

Monitoring Guideline. 

To realize this goal, the GRE team is systematically 

working towards providing each of the identified 270 

natural area parks with a geologic scoping meeting, a 

digital geologic map, and a geologic report. These 

products support the stewardship of park resources and 

are designed for non- geoscientists. During scoping 

meetings the GRE team brings together park staff and 

geologic experts to review available geologic maps and 

discuss specific geologic issues, features, and processes. 

Scoping meetings are usually held for individual parks 

and on occasion for an entire Vital Signs Monitoring 

Network. The GRE mapping team converts the geologic 

maps identified for park use at the scoping meeting into 

digital geologic data in accordance with their innovative 

Geographic Information Systems (GIS) Data Model. 

These digital data sets bring an exciting interactive 

dimension to traditional paper maps by providing 

geologic data for use in park GIS and facilitating the 

incorporation of geologic considerations into a wide 

range of resource management applications. The newest 

maps come complete with interactive help files. As a 

companion to the digital geologic maps, the GRE team 

prepares a park- specific geologic report that aids in use 

of the maps and provides park managers with an 

overview of park geology and geologic resource 

management issues. 

For additional information regarding the content of this 

report and up to date GRE contact information please 

refer to the Geologic Resource Evaluation web site 

(http://www2.nature.nps.gov/geology/inventory/). 

Geologic Setting 

Theodore Roosevelt National Park is situated mostly 

within the confines of the Little Missouri River valley in 

the remote southwestern corner of North Dakota (figure 

1). This part of the Great Plains hosts a landscape that has 

changed little since 1883 when 24- year- old Theodore 

Roosevelt came west to hunt buffalo (figure 2). The park 

commemorates Theodore Roosevelt, the 26th U.S. 

president, who began to develop his conservation ethic 

in this place. The setting made a deep impression on the 

young man and influenced his presidential administrative 

policy, which promoted access to and sustainable use of 

public lands. 

The Little Missouri River flows northward from Devils 

Tower and the Black Hills past Theodore Roosevelt 

National Park and on to the confluence of the Missouri 

River. The Missouri Plateau section of the Great Plains 

(figure 3) reflects the thorough dissection of the 

landscape by the Missouri River and its tributaries. The 

Little Missouri River flows through the South Unit of the 

park, past Roosevelt’s ranch site, and into the North Unit 

where it turns abruptly eastward and joins the Missouri 

River about 80 km (50 miles) away (figure 4). 

The Missouri River and its tributaries (e.g., the Little 

Missouri River in North Dakota and the Yellowstone 

River in Montana) carved the Missouri Plateau into 

confined valleys, broad upland surfaces at many levels, 

and terraces along the rivers. Locally, high buttes rise 

above the uplands; these are remnants of former 

interstream divides. Continental ice sheets also dammed 

many tributary valleys, forming large lakes (Trimble 

1993). Recession as a result of badlands development has 

widened some of the area’s larger valleys. 

The Little Missouri River valley is part of the Missouri 

Plateau of the Great Plains, which consists of two distinct 

sections: glaciated and unglaciated (figure 4). The 

boundary between the sections occurs in the park and is 

marked by glacial erratics (boulders) and cobbles. To the 

north of this glacial limit, much of the Missouri Plateau is 

a plain of little relief with muted landforms covered by a 

thick blanket of glacial debris. To the south the 

unglaciated Missouri Plateau displays the greatest variety 

of landforms of any section of the Great Plains (e.g., 

small mountains, plateaus, river valleys, and badlands) 

(Trimble 1993). Most of Theodore Roosevelt National 

Park is situated on the unglaciated Missouri Plateau. 
 THRO Geologic Resource Evaluation Report 3

Precipitation in the region comes as sudden showers, and 

storms commonly drop several inches of rain per hour 

(Opdahl et al. 1975). This sudden influx of precipitation 

causes runoff and rapid erosion of the poorly 

consolidated sediments, forming highly dissected 

badlands topography. In addition, fused then broken 

beds of burnt coal facilitate erosion during runoff events. 

Seasonally, small tributaries flow down the steep valley 

sides along the Little Missouri River, cutting into the 

strata of the Fort Union Group: shales, clays, sandstones, 

silts, and lignite of the Bullion Creek and Sentinel Butte 

formations. 

In general, the shales and clays are gray to brown, and 

the sandstones tend to appear yellowish orange to buff 

and tan. Blue bentonite in the Sentinel Butte Formation 

adds another colorful layer to the landscape. Lignite is 

dark brown to black. Possibly the most noticeable strata 

in the park are the red beds, locally called “scoria,” but 

more correctly called “clinker.” The colorful, 

interbedded strata on the hillsides of the park add much 

to the scenic beauty of the badlands. 

Figure 1. Location Map of Theodore Roosevelt National Park. 

Figure 2. Bison in the South Unit Crossing the Little Missouri River. When Theodore Roosevelt was 24 years old, he came to the region 

to hunt buffalo. The rugged landscape matched Roosevelt’s individualism and influenced his thinking. NPS photo by Dave Krueger.
 NPS Geologic Resources Division 4 

Figure 3. Physiographic Areas of the Great Plains. Theodore Roosevelt National Park spans the glaciated and unglaciated portions of 

the Great Plains Physiographic Province. Other National Park System units of the Great Plains include Agate Fossil Beds National 

Monument (Nebraska), Badlands National Park (South Dakota), Bent’s Old Fort National Historical Site (Colorado), Capulin Volcano 

National Monument (New Mexico), Devils Tower National Monument (Wyoming), Jewel Cave National Monument (South Dakota), Mount 

Rushmore National Memorial (South Dakota), and Wind Cave National Park (South Dakota). 
 THRO Geologic Resource Evaluation Report 5

Figure 4. Detailed maps of the North and South Units in Theodore Roosevelt National Park. 
 NPS Geologic Resources Division 6 

Geologic Issues 

A Geologic Resource Evaluation scoping session was held for Theodore Roosevelt 

National Park on June 10, 2002 to discuss geologic resources, address the status of 

geologic mapping, and assess resource management issues and needs. The following 

section synthesizes the scoping results, in particular, those issues that may require 

attention from resource managers. 

The land management plan for Theodore Roosevelt 

National Park identifies oil and gas development in the 

vicinity of the park as the single greatest concern for 

resource management; thus, this issue is listed first. 

Following in alphabetical order are other issues that may 

require attention from resource managers. 

Oil and Gas Development 

Under federal statute Theodore Roosevelt National Park 

is off limits to federal oil and gas development. 

Nonetheless, at the height of the energy crisis in the 

1970’s, federal oil and gas leases were issued in the park. 

No subsequent leases have been issued in the park 

although periodic interest is expressed in such 

development. The park lies within the Williston Basin. 

This structural- sedimentary intracratonic basin—

covering portions of North Dakota, Montana, South 

Dakota, and south- central Canada (Manitoba and 

Saskatchewan)—is a major producer of oil and gas, 

lignite, and potash. The deepest portion of the Williston 

Basin is centered in North Dakota and includes 

approximately 15,000 feet (4,500 m) of Phanerozoic 

(table 1) sedimentary rocks. Carbonate sedimentary 

rocks are the major oil and gas producing units, and 

clastic sedimentary rocks contain abundant lignite. 

Energy development on lands adjacent to the park is 

negatively affecting air and water quality; scenic views; 

dark night skies; wildlife and plants, including threatened 

and endangered species; cultural resources; and natural 

quiet. 

Oil and gas were first discovered in the Montana portion 

of the Williston Basin in 1936, then in Manitoba in 1950, 

and in North Dakota in 1951. During the last half of the 

1970s, development of the United States’ portion of the 

basin was remarkable in its identification of previously 

unrecognized structures, discovery of new producing 

zones, and high success rates (Gerhard et al. 1982). In 

1970, the entire U.S. portion of the basin averaged 20 

active drilling locations; in 1980 the average number had 

increased to 150 drilling locations (Gerhard et al. 1982). 

Statistics from the Industrial Commission of North 

Dakota show that at its peak in 1984 annual production in 

North Dakota was 52,658,396 barrels of oil produced 

from 3,546 wells. 

North Dakota ranks 9th among U.S. states in production 

of oil and gas. Most ND production occurs on USDA 

Forest Service lands in Billings and McKenzie counties. 

According to statistics from the North Dakota Industrial 

Commission, Oil and Gas Division, these two counties 

produce the most oil of the 19 producing counties in the 

state. Theodore Roosevelt National Park is located in 

Billings and McKenzie counties. Peak production for 

Billings County occurred in March 1981 (1,726,136 

barrels); McKenzie County peaked in May 1985 with 

(1,472,169 barrels). 

The Little Missouri Grasslands National Forest 

surrounds Theodore Roosevelt National Park and has 

the most productive oil fields in the U.S. National Forest 

System (Hinchman 1993). This national forest lies along 

the Montana border and has about 600 federally 

permitted wells. According to the USDA Forest Service, 

Dakota Prairie Grasslands/Montana State Office Oil and 

Gas Leasing Record of Decision (June 2003), well pads, 

access roads, and installation of tank batteries, power 

lines, and pipelines are associated with each well. Well 

pads are generally about 5 acres (2 ha) and contain the 

well head, reserve pit, storage tanks, other equipment, 

and temporary living quarters. Typical production may 

disturb a site for 40 years. Approximately 100 additional 

wells occur on lands where surface ownership is federal 

and subsurface mineral ownership is nonfederal (USDA 

Forest Service 2001). 

In areas with active oil production the potential exists for 

spills and leaks of drilling fluids, muds, oil, or other 

waste. Drilling fluids and groundwater encountered in 

the drilling process are often high in dissolved salt and 

sometimes contain heavy metals such as barium, 

cadmium, chromium, lead, strontium and zinc. Spills or 

leaks of detergents, fuels, machinery fluids, and/or toxic 

chemicals are also a risk of oil production activities 

(Iierkley et al. 1998). 

The only oil and gas production in the park is on federal 

leases in the South Unit. In 1975, 12 federal oil and gas 

tracts totaling 1,316 acres (533 ha) were competitively 

leased within the South Unit due to concerns with the 

“drainage” of federal oil and gas from inside the park by 

external development. Today, such concerns would be 

addressed through “compensatory royalty agreements” 

which give the federal government a share in the 

revenues generated by nonfederal oil and gas 

development outside the park that drain federal oil and 

gas in the park. Leases in the South Unit include a “no 

surface occupancy” stipulation that prohibits drilling and 

production activities within the park. Seven wells with 

surface locations south of the park were directionally 

drilled beneath the park into the federal leases from 1974 
 THRO Geologic Resource Evaluation Report 7

through 1995. As of December 2004, one of these wells is 

producing oil and gas, one is plugged, and five are 

currently not producing hydrocarbons (statistics from 

North Dakota Industrial Commission, Oil and Gas 

Division). 

In 2002, the National Park Service completed an 

Environmental Assessment (EA) that proposed to 

expand the Elkhorn Ranch Unit to 6,581 acres (2,663 ha) 

(National Park Service 2002). Elkhorn Ranch, situated 

between the North and South units, contains both 

privately held mineral rights and federal oil and gas 

leases. Since the final EA and a 2003 finding of no 

significant impact (FONSI), the USDA Forest Service has 

purchased this property under a “no net gain” 

procedure. The USDA Forest Service will continue to 

recognize all rights associated with valid federal leases 

within the Elkhorn Ranch (Bruce Kaye, Theodore 

Roosevelt National Park, personal communication, April 

24, 2007). 

Abandoned Mine Lands 

In the early 1990s, staff from the U.S. Department of 

Interior, Office of Surface Mining, identified hazardous 

conditions at an abandoned mine land (AML) site in 

Theodore Roosevelt National Park. As a result of 

collapse of the overlying strata, the original mine 

entrances were subsiding. The two openings were not in 

coal seams but in the weakly consolidated mudstone, 

siltstone, and sandstone of the overlying cliff face. The 

weak nature of these bluffs made entry mitigation 

hazardous (Phil Cloues, NPS Geologic Resources 

Division, written communication, November 16, 2004). 

Coal- bed methane was an additional hazard associated 

with this abandoned coal mine. As atmospheric pressure 

conditions fluctuate, methane gas from the underlying 

coal seam is forced upward through rock fractures. If 

methane is present at high enough concentrations, 

explosive conditions can form in mine openings. In 

addition, suffocation hazards existed due to oxygendeficient conditions (Dave Shaver, NPS Mining and 

Minerals Branch, memorandum, June 1, 1992). 

Staff from the NPS Mining and Minerals Branch (now 

the Geologic Resources Division) investigated the site 

and recommended permanent closure of two openings 

based on its assessable location behind an NPS 

maintenance building in Medora, signs of frequent 

visitation, and unstable conditions. The NPS Geologic 

Resources Division funded the project using AML 

Program funds. 

Using AML funds park maintenance staff permanently 

closed the two openings in 1999. The larger of the two 

openings, referred to as the “east opening,” sloped down 

into the mine and was approximately 25 feet (7 m) above 

the base of the cliff face. Using long poles so that no one 

had to enter the unsafe openings, park staff injected 17 

bags of polyurethane foam (PUF), which at the time was 

new technology. 

About 200 feet (60 m) west of the larger hole, the smaller 

opening, referred to as the “west opening,” contained a 

set of mine rails that extended out of the old collapsed 

portal. Park staff released four bags of PUF in this almost 

vertical opening and then backfilled it. Park maintenance 

staff completed the closures in about five hours under 

very hot conditions. The cost was 10% of the original 

estimate that would have involved blowing sand up to 

the hazardous openings (Phil Cloues, NPS Geologic 

Resources Division, written communication, November 

16, 2004). No other AML sites are known in the park and 

no further mitigation is required at this site but periodic 

monitoring of the site would be prudent to ensure the 

continued integrity of the closures. 

Coal Fires 

Wildfires are a natural element in the ecology of the 

region. This coupled with abundant exposures of lignite 

in the Fort Union Group creates a resource management 

issue for Theodore Roosevelt National Park. When 

drought or regional downwasting by erosion lowers the 

groundwater table below the top of a coal bed, the 

exposed bed has a high probability of burning. Lignite 

beds, therefore, pose a problem for park planning and 

management, and the park’s prescribed burn program 

must take into account outcrops of lignite. During the 

June 10, 2002, scoping meeting, participants suggested 

that a GeoScientist- in- the- Park (GIP) could identify 

and map high- potential areas. This data could be added 

to the park’s GIS. Park managers are encouraged to 

contact the Geologic Resources Division for information 

about the GIP Program. 

No lignite fires are known to be burning in the park at 

present (Bruce Kaye, THRO, personal communication, 

April 24, 2007). However, several small fires burned in 

the northeastern corner of the South Unit in the late 

1980s and early 1990s, and resource managers can expect 

future burns. Grass fires, lightning strikes, and 

spontaneous combustion may ignite lignite beds. 

Ranchers have also been known to inadvertently build 

campfires on coal refuse piles, which have burnt out of 

control and started coal- bed fires (Heffern et al. 1993). 

Some of the lignite fires, which started as a result of the 

lightning- ignited Buck Hill fire in July 1988, appear to be 

the result of burning juniper roots, which reach down 

from the surface to underlying coal beds (Bluemle 1988). 

Given the right kind of coal, oxygen, and a certain 

temperature and moisture content, coal will burn by 

itself (Department of Energy 1993). The “ideal” situation 

favoring spontaneous combustion is a combination of 

finely divided coal layers, a slight amount of heat from an 

outside source (sunlight), and several feet of overburden 

to retard heat losses by radiation (Bluemle 1988). 

Absorption of oxygen takes place at ordinary 

temperatures and because this process generates heat, it 

is self- generating (Bluemle 1988). 

Side- cutting of a stream, a landslide, or rapid erosion can 

expose fresh coal to the air; mines also penetrate into 

fresh, unweathered coal. Given sufficient ventilation, a 
 NPS Geologic Resources Division 8 

well- oxygenated burning lignite bed can reach 

temperatures of 3,640°F (2,000°C). This high heat bakes 

overlying sediments into glassy slag (Biek and Gonzalez 

2001). Clinker is the term used to describe the slaggy or 

vitreous residue of mixed rock and coal ash left after 

burning. As lignite burns, its volume is significantly 

reduced creating a void space into which the overlying 

sediments collapse. Fractures in the slumped sediment 

allow oxygen to reach the fire and combustion gases to 

escape. Ultimately an underground coal fire burns all the 

coal that it can reach before running out of air or fuel. 

The fire extinguishes naturally where overburden 

becomes so thick that fractures from the collapse fail to 

reach the surface to draw more air, or when the fire 

burns down to the water table (Heffern and Coates 

2004). Aside from the obvious fire danger, the principal 

resource management issue posed by burning lignite 

beds is the slumping network of fractures that develop 

(Biek and Gonzalez 2001). 

Coal Resources and Mining 

Under the Surface Mining Control and Reclamation Act 

(SMCRA)of 1977, surface coal mining is prohibited in 

units of the National Park System unless an entity holds 

“valid existing rights” to mine (see 30 U.S.C. §1272 (e) (1)). 

No such rights exist in Theodore Roosevelt National 

Park. The statute covers proposed surface coal mining on 

federal, state, and private land. Nonetheless, coal rights 

exist outside the park. SMCRA also prohibits mining 

external to park boundaries if the proposed development 

will adversely affect the park. This provision also 

contains the “valid existing rights” exception (see 30 

U.S.C. §1272 (e) (3)). 

Lignite, a low- rank coal, is a prominent part of the Fort 

Union Group (figure 5). Pencil- thin to foot- thick beds 

of lignite formed in ancient swamps within the Williston 

Basin (see “Geologic History” section). Long- term 

stability and slow subsidence of the Williston Basin 

contributed to the remarkable lateral continuity of these 

lignite deposits. 

The lignite at Theodore Roosevelt National Park is often 

exposed and frequently burns. This burning produces 

another interesting rock type, locally called “scoria.” The 

geologic term scoria, however, refers to dark- colored, 

porous rock associated with basaltic lava flows. No such 

igneous rocks occur in the park, so the correct term for 

the material found in the park is “clinker” (figure 6). In 

some places in the park, clinker melted and flowed like 

slag from a blast furnace. This flow structure and the 

porous nature of some clinker may be what caused early 

settlers to call this rock “scoria” (Laird 1950). 

Clinker is the residue formed by burning lignite seams, 

which have fused and baked overlying sands, shales, and 

clays. Clinker is generally red due to the presence of 

iron- rich hematite, but varies from black to pale pink, 

depending on the characteristics of the original sediment 

and degree of oxidation or reduction during burning. 

Heating turns calcium carbonate- rich sediments yellow. 

As heating continues, the shale and siltstone become 

intensely fractured, and ochre hues give way to darker, 

more intense shades of orange and red (Heffern and 

Coates 2004). 

Clinker is used for road base and ornamental lawn and 

garden material. Clinker has been quarried in at least one 

location in the South Unit, just east of Johnson’s Plateau. 

The location is labeled as “scoria pit” on the USGS 

topographic map of the park. The extracted material was 

used for road construction. Though locally abundant, 

the material was reportedly of poor quality; therefore, 

park managers do not foresee any future use of this site 

(Keith Butler, Theodore Roosevelt National Park, 

memorandum, December 21, 1992). 

Clinker is a major factor in the development of the North 

Dakota badlands. Natural burning of the lignite beds 

throughout western North Dakota has resulted in broad 

areas of hardened clinker- capped landforms. Clinker is 

more resistant to erosion than nearby unbaked rocks. 

Differential erosion leaves clinker as a cap on redtopped knobs, ridges, and mesas throughout the park 

(figure 7). These features rise above the more subdued 

topography of the less- resistant strata (Bluemle 1988). 

Clinker also forms an irregular collapsed topography 

referred to as “thermo- karst.” However, this should not 

be confused with true karst, which forms by dissolution, 

rather than heating and collapse. 

The first European settlers and the Northern Pacific 

Railroad Company mined lignite near Medora as early as 

1884. In the 1950s and early 1960s, uranium- rich lignite 

was mined both southeast and northeast of the South 

Unit, at Rocky Ridge and an area south of Fairfield 

respectively. Under the guidance of the NPS Geologic 

Resources Division, park maintenance staff permanently 

closed hazardous mine openings on park land in 1999 

(see “Abandoned Mine Land” section). Today, lignite 

mining is excluded (withdrawn from leasing) inside 

Theodore Roosevelt National Park. However, North 

Dakota is the site of the world’s largest known lignite 

deposits (Wiebmer 1977). The thickest lignite beds in 

North Dakota are just west of the North Unit; however, 

these particular beds are too deep to mine from the 

surface in this area (Ed Murphy, North Dakota 

Geological Survey, oral communication, December 2, 

2004). Nevertheless, the potential remains for 

development of coal- bed methane from the Fort Union 

Group in the vicinity of the park. 

With present technology, the high- moisture content, 

low- heat content, and potential for spontaneous 

combustion of the lignite deposits in the vicinity of 

Theodore Roosevelt National Park makes these deposits 

uneconomical and difficult to transport over long 

distances (Russell Dickenson, NPS Director, 

memorandum to Assistant Secretary, Fish and Wildlife 

and Parks, January 18, 1983). For these reasons, this 

particular lignite would need to be processed on site. In 

the present climate of high energy prices, companies 

(e.g., Great Northern Properties, the mining enterprise of 

the Northern Pacific Railroad Company) are 
 THRO Geologic Resource Evaluation Report 9

reinvestigating the potential for establishing a coal mine 

and power plant southeast of the South Unit despite 

these obstacles (Ed Murphy, North Dakota Geological 

Survey, oral communication, December 2, 2004). Coal 

industry representatives have discussed gasification as a 

means to generate electricity in proposed power plants in 

the region. Gasification refers to the conversion of lignite 

to gas, in this case for fueling boilers. If high energy 

prices continue, a coal- fired power plant between 

Dickinson and Belfield may be forthcoming (Jim 

Deutsch, North Dakota Public Service Commission, oral 

communication, December 6, 2004). 

While the deposits of lignite are fixed in place, mining 

activity is dependant on market prices, and economics 

will provide the driving force for future mining. The 

North Dakota Geological Survey has produced 

1:125,000- scale county maps of the economically 

recoverable (from the surface) lignite in western North 

Dakota, which may be of use to resource managers for 

identifying economically feasible coal mining near the 

park. 

GRD staff recommends that park staff maintain good 

communication with the Bureau of Land Management, 

which administers federal leases, to weigh in on leasing 

decisions and to raise the SMCRA prohibitions designed 

to protect park resources from surface coal mining. Early 

involvement in the permitting process near other 

National Park System units (e.g., New River Gorge 

National River, West Virginia, and Big South Fork 

National River and Recreation Area, Tennessee) has 

proven to be effective in minimizing serious impacts to 

park resources. Table 2 lists potential major effects of 

surface mining on park resources. 

Flooding and Fluvial Erosion 

The Little Missouri River flows through 9 miles (14 km) 

of the South Unit, 14 miles (23 km) of the North Unit, and 

across Elkhorn Ranch (figure 8). The river flows 

undisturbed and is a designated state scenic river 

(Theodore Roosevelt National Park, Natural Resource 

Management Plan and Environmental Assessment, July 

1984). The river has also been considered for federal wild 

and scenic river status (Theodore Roosevelt National 

Park, Land Protection Plan, June 1990). Congress 

granted a portion of another Little Missouri River in 

Arkansas “wild and scenic” status in April 1992; 

authorization is still pending for the North Dakota 

segment (National Wild and Scenic Rivers System, 

http://www.rivers.gov/publications/rivers- table.pdf, 

April 23, 2007). With the exception of the Little Missouri 

River, the creeks within the park are mostly ephemeral. 

However, the lower 1.5 miles (2.4 km) of Knutson Creek 

is permanent, flowing from the west 2.5 miles (4 km) 

through the South Unit of the park to the Little Missouri 

(Theodore Roosevelt National Park, Natural Resource 

Management Plan and Environmental Assessment, July 

1984). 

The town of Medora, Cottonwood Campground, Squaw 

Creek Campground, Peaceful Valley Ranch, South Unit 

park headquarters, and portions of the park road are 

located within the Little Missouri River 100- year 

floodplain. These areas are especially prone to 

inundation during rapid spring thaws with periods of ice 

jams (Theodore Roosevelt National Park, Natural 

Resource Management Plan and Environmental 

Assessment, July 1984). The floodplain and terraces (unit 

Qal on the geologic map) flanking the Little Missouri 

River will be inundated during a 100- year flood event 

(Biek and Gonzalez, 2001). A 100- year flood does not 

refer to an event that occurs once every hundred years; a 

100- year flood can happen any year or a number of years 

in a row. The term is a statistical designation. Specifically, 

a 100- year flood has a 1% chance of occurring in any 

given year. Flood discharges for the Little Missouri River 

were reported in Emerson and Macek- Rowland (1986) 

and are presented here in table 3. 

Flooding from the Little Missouri River and tributary 

creeks both cause hazards for persons and property. 

However, the flood hazard of the Little Missouri River is 

very different than that of the smaller tributary creeks. 

The threat of flooding may be known days in advance 

along the Little Missouri River because it has a relatively 

large drainage basin. In contrast, intense, localized 

thunderstorms will most likely cause flash flooding in the 

smaller tributaries, which may at most be predicted only 

hours in advance. Storm runoff will fill the floodplain of 

the relatively narrow tributary valley and flow 

downslope at high velocity. Once the flood waters of a 

tributary reach the mouth of the valley, they will flow 

into the wider floodplain of the Little Missouri River, 

quickly dispersing, shallowing, and slowing substantially 

(Emerson and Macek- Rowland 1986). 

As the Little Missouri naturally meanders across its 

floodplain, sediment is eroded from the outside bend of 

the meander and deposited along the inside bend. This 

flow causes the channel to migrate laterally across the 

floodplain, continuously reshaping the surface (Biek and 

Gonzalez 2001). Abandoned channels and oxbow lakes 

(see “Oxbow” section) record the geomorphological 

changes on the valley floor. Because of their proximity to 

the river, facilities such as Juniper and Cottonwood 

campgrounds may be adversely affected by channel 

migration and bank erosion. Additionally, meandering 

and resulting erosion are threatening Squaw Creek 

Campground in the North Unit and land adjacent to the 

Elkhorn Ranch site. 

The NPS Water Resources Division briefly addresses 

floodplain hazard identification and other water related 

management issues in the Theodore Roosevelt National 

Park Water Resources Management Plan available online 

(http://www.nature.nps.gov/water/completedwrmp). 

Mass Wasting 

According to Biek and Gonzalez (2001), mass wasting in 

Theodore Roosevelt National Park occurs primarily as 

landslides and soil creep. The steep, sparsely vegetated 

slopes in the park are continually reshaped by erosion. 

Small- scale landslides are a ubiquitous part of this 
 NPS Geologic Resources Division 10 

process and most landslides show multiple episodes of 

slumping (Biek and Gonzalez 2001). 

Factors such as lithology, steepness of slopes, and the 

presence of bentonite influence mass- wasting processes 

in the park. Most mass wasting occurs in the mixed strata 

of the Sentinel Butte Formation. Soil creep is also 

particularly common on steep north- and northeastfacing slopes of the Bullion Creek Formation in the 

South Unit (Biek and Gonzalez 2001). North- facing 

slopes that contain layers of Sentinel Butte bentonite 

tend to retain moisture longer, making them more 

susceptible to landsliding (GRI workshop, meeting 

notes, June, 10, 2002). 

Road construction activities in the park have locally 

exacerbated landsliding. Buckled pavement and dips in 

the road attest to continued movement in several places 

within the park (Biek and Gonzalez 2001). For instance, 

in the South Unit, the park road runs over landslide 

deposits near the trailhead to Ridgeline Trail and along 

the road to Buck Hill. In the North Unit, the scenic drive 

regularly intersects landslide deposits between 

Concretion Pullout and the junction to Highway 85. 

Ground disturbing activities such as placing fill, 

regrading, and altering drainage patterns in such deposits 

may lead to increased instability (Biek and Gonzalez 

2001). 

The most pronounced landslides are in the North Unit, 

where two classic types of rotational slumps are present 

(figure 9). First, large, complex slumps with hummocky 

surfaces occur along the length of the Little Missouri 

River valley. The largest of these is on the north flank of 

Achenback Hills. Achenback Spring flows from the 

headwall of this landslide. 

The second classic type of rotational slump is found 

north of the Little Missouri River between the east 

entrance and Juniper Campground. Here, large coherent 

blocks with beds dipping into the hillside at 25° to 50°, 

and numerous small displacements within these blocks, 

collectively accommodate stresses resulting from block 

rotation (Biek and Gonzalez 2001). The presence of 

undisturbed, horizontal Sentinel Butte strata at the toe of 

these rotated blocks shows that these blocks were 

emplaced by rotational slumping and not faulting (Biek 

and Gonzalez 2001). 

Paleontological Resources 

During a detailed study of 10 square miles (26 km2) of the 

park (about 1/10 of the entire area) in 1994, investigation 

showed that both the Bullion Creek and Sentinel Butte 

formations are quite fossiliferous (table 4). Investigators 

mapped 400 fossil sites in the study area. This is an 

average of 40 fossil sites per square mile. The most 

common kind of fossil in the park is petrified wood, 

which occurs sporadically at several stratigraphic levels 

in the Sentinel Butte and Bullion Creek formations. The 

abundance of petrified wood and the many upright and 

intact petrified stumps are evidence of the presence of 

forests in many areas of the South Unit during deposition 

of the Sentinel Butte Formation (figure 10). Some of these 

trees were massive, leaving stumps 7 to 8 feet (2.1 to 2.4 

m) in diameter (Hoganson and Campbell 1997). Despite 

the size of the petrified logs, vestiges of large roots are 

absent from the petrified stumps and from soil profiles. 

Though poor preservation has hindered specific 

identification of the wood types, most of the trees were 

probably conifers (Hoganson and Campbell 1997). 

Remains of freshwater mollusks (i.e., snails and small 

snail opercula, mussels, and pill clams) are also abundant, 

and ostracodes (small bivalved crustaceans) are present. 

Shelly remains are so abundant at some localities that 

they form coquina beds. 

In addition to abundant petrified wood and mollusks, 

many others kinds of plant and animal fossils occur in 

Theodore Roosevelt National Park. Some of the fossil 

stumps and logs show evidence of damage (i.e., trace 

fossils) from Paleocene- age insects and birds. 

Investigators found only one insect (body) fossil, a beetle 

(Coleoptera), during the study. Fossils are primarily from 

the Paleocene but some are as recent as the Quaternary. 

According to the park’s 1984 natural resource 

management plan and environmental assessment, few 

problems with illegal collecting have occurred, despite 

abundant fossil exposure throughout the park. Fossil 

localities are monitored through normal patrol activities. 

However, the Petrified Forest Plateau area is considered 

a “particularly sensitive area” and this and other 

backcountry areas are difficult to patrol. 

Managing and protecting fossils relies upon an 

understanding of geologic and geographic abundance, 

occurrence, and distribution, as well as the factors 

threatening stability such as weather and climate, rates of 

erosion, and human activity. In order to quantify fossil 

loss, NPS paleontologists have established a system of 

measurable indicators of change to baseline resource 

conditions (table 5). Paleontological localities at 

Theodore Roosevelt National Park vary widely in terms 

of rock types, degree of preservation, geomorphic 

characteristics, and accessibility. Therefore, a specific 

indicator may not be useful or appropriate at all fossil 

sites. Nevertheless, this monitoring strategy provides a 

multidimensional approach to assessing or measuring 

impacts to in situ paleontological resources, which may 

be useful for resource managers at Theodore Roosevelt 

National Park (see Santucci and Koch 2003; available at 

http://www2.nature.nps.gov/ParkScience/index.cfm?Arti

cleID=16 [accessed April 18, 2007]). 

Piping 

According to the USGS “Water Basins Glossary” at 

http://capp.water.usgs.gov/GIP/h2o_gloss/, piping is 

“erosion by percolating water in a layer of subsoil, 

resulting in caving and in the formation of narrow 

conduits, tunnels, or ‘pipes’ through which soluble or 

granular soil material is removed.” Piping is a major 

management issue in anthropogenic areas such as 

earthen dams and raised roads (Pete Biggam, NPS soils 

scientist, e- mail communication, February 23, 2007). 
 THRO Geologic Resource Evaluation Report 11

Piping can also occur in natural settings, typically when 

sheetwash erosion (see “Sheetwash Erosion” section) 

starts to concentrate into rill erosion, entering a soil 

through cracks, animal burrows, fence- post holes, or 

excavations, and eventually moving through the 

subsurface to an exit point (Pete Biggam, NPS soils 

scientist, e- mail communication, February 23, 2007). 

Pipes are most common on and near the base of steep 

slopes at Theodore Roosevelt National Park (figure 11). 

The principal danger associated with erosional pipes is 

roof collapse (Biek and Gonzalez 2001). 

Swelling Soils and Bentonite 

Sixty million years ago, volcanoes erupted far to the west 

of Theodore Roosevelt National Park spewing ash into 

the atmosphere. Rivers and wind transported and 

deposited this ash across the northern Great Plains. 

Chemical weathering altered the ash into bentonite—

soft, malleable clay that is composed largely of smectite. 

As mapped by Biek and Gonzalez (2001) in Theodore 

Roosevelt National Park, bentonite of the Sentinel Butte 

Formation appears as bluish colored bands in the 

badlands. These beds can be traced for miles along the 

Little Missouri River (figure 12). When wet, bentonite 

can expand up to 16 times in volume. The inherent 

swelling and shrinking of bentonite can cause structural 

damage to buildings, roads, and other infrastructure. 

Wet bentonite produces slippery, hazardous conditions 

cross country and on trails and roads. Upon drying the 

clay contracts and forms the “popcorn” surface 

characteristic of bentonite. 

Bentonite is also an economic resource, though the small 

deposits in North Dakota are unlikely to be of economic 

value (Biek and Gonzalez 2001). Bentonite is added to 

drilling mud to cool cutting tools, remove cuttings, 

lubricate drill bits, prevent blowouts, and confine 

underground fluids by creating an impervious coating. 

Moreover, bentonite is used as a binder for foundry sand 

and for pelletizing iron ore. It also serves as a sealant or 

liner for landfills, ponds, and canals. It is an additive used 

as a filler, stabilizer, or extender in materials such as 

adhesives, greases, medicines, cosmetics, paint, rubber, 

and soaps. Most of the bentonite used in the United 

States comes from Wyoming.

Table 1. Geologic Time Scale 

Eon Era Period Epoch Age (Ma) Age of 

Holocene 0.01 Quaternary Pleistocene 1.81 

Pliocene 5.33 Neogene 

Miocene 23.0 

Oligocene 33.9 

Eocene 55.8 

Cenozoic 

Paleogene 

Tertiary 

Paleocene 65.5 

Mammals 

Cretaceous 145.5 

Mesozoic Jurassic 199.6 

Triassic 251.0 

Reptiles 

Permian 299 

Pennsylvanian 318 Carboniferous Mississippian 359.2 

Amphibians 

Devonian 416.0 

Silurian 443.7 Fishes 

Ordovician 488.3 

Phanerozoic 

Paleozoic 

Cambrian 542.0 Invertebrates 

Proterozoic 2,500 

Archean 3,800?–2,500 

Hadean 

Also known as Precambrian 

4,600?–3,800 

Notes: Dates are in millions of years (Ma) and indicate the beginning of each associated period or epoch. Dates reflect 

the International Union of Geological Sciences (IUGS), International Stratigraphic Commission (ICS), International 

Stratigraphic Chart (2004) at http://www.stratigraphy.org/down.htm. The International Stratigraphic Commission 

does not list the boundary between Archean and Hadean. However, the U.S. Geological Survey lists this boundary at 

approximately 3,800 Ma and the formation of Earth at approximately 4,600 Ma, which are used here. Mississippian 

and Pennsylvanian are terms used primarily in North America. Tertiary is no longer used by the International 

Commission on Stratigraphy (2004) but is listed here because it is still in common use. 
 NPS Geologic Resources Division 12 

Table 2. Potential Impacts of Surface Mining on Park Resources 

Mining operation 

Exploration 

Area 

dewatering 

and diversion 

Drilling 

Blasting 

Stripping 

(overburden 

removal) 

Haulage 

Top soil or 

other soil 

storage 

Maintenance 

Beneficiation 

Geology and soil 

Soil erosion * * * * 

Soil organisms * * * * 

Overburden swelling * 

Toxic strata * * * 

Soil inversion * 

Soil stability * 

Landslides * 

Spoil piles * * 

Oil spills * * * 

Coal spills * 

Water 

Aquifer effects * * * 

Runoff alteration * * * 

Sediments * * * 

Toxic substances * * 

Groundwater contamination * * * 

Industrial effluents * 

Sludge * 

Air 

Exhaust emissions * * * * * 

Dust * * * * * * * * 

Other (e.g., welding) * * 

Blasting fumes * 

Wildlife and plants 

Vegetation potential * 

Habitat altered (including migration routes) * * * * * 

Species diversity * 

Aquatic life * 

Animal essentials * 

Accidents/Deaths * * 

Wildlife disturbed * * * * * * 

Other 

Aesthetic (including wilderness values) * * * * * 

Noise * * * * * * * 

Dangerous material * * 

Source: Ramani and Grim (1978). 

Table 3. Flood Discharges for Little Missouri River and Tributaries in Theodore Roosevelt National Park 

Peak 

recorded 

discharge 

Maximum 

water-surface 

elevation 

Date 100-year flood 

discharge 

500-year flood 

discharge 

North Unit 110,000 cfs 1,953.03 ft asl March 25, 1947 78,800 cfs 113,500 cfs 

South Unit 65,000 cfs 2,267.25 ft asl March 23, 1947 65,300 cfs 99,300 cfs 

Elkhorn Ranch No data No data 69,000 cfs 103,000 cfs 

Knutson Creek 31,800 cfs 

Paddock Creek 13,500 cfs 

Squaw Creek 24,600 cfs 

Notes: Discharges are in cubic feet per second (cfs). Maximum water- surface elevations are in feet above sea level 

(asl). Source: Emerson and Macek- Rowland (1986). 
 THRO Geologic Resource Evaluation Report 13

Table 4. Fossils at Theodore Roosevelt National Park

Fossil type Formation 

Petrified wood Bullion Creek and Sentinel Butte 

Freshwater mollusks Bullion Creek and Sentinel Butte 

Ostracodes (small bivalved crustaceans) Sentinel Butte 

Coleoptera (beetle) Sentinel Butte 

Leaves (e.g., angiosperms and ferns) Bullion Creek and Sentinel Butte 

Seeds (e.g., Cercidiphyllum [katsura tree]) Bullion Creek and Sentinel Butte 

Twigs, roots, and branches Taylor bed of the Golden Valley Formation 

Champsosaurs (crocodile- like creature), including common 

Champsosaurus and extremely rare Simoedosaurus Bullion Creek and Sentinel Butte 

Crocodiles (probably Leidyosuchus) Bullion Creek and Sentinel Butte 

Alligators Sentinel Butte 

Turtles (Protochelydra—chelydrid [snapping turtle], and 

Plastomenus—plastomenid [soft- shelled turtle]) Sentinel Butte 

Fish (Amia [bowfin] and Lepisosteus gar.) Bullion Creek and Sentinel Butte 

Giant salamander (Piceoerpeton) Sentinel Butte 

Plesiadapis (lemur- like mammal) Sentinel Butte 

Bison Quaternary alluvial and colluvial deposits 

Source: Hoganson and Campbell (1997). 

Table 5. Factors Affecting the Stability of In Situ Paleontological Resources 

SURFACE 

Physical Chemical Biological Human 

Tectonics 

• Seismicity 

• Folding/faulting 

• Extrusive events (lava 

flows) 

Weathering/Erosion 

• Solar radiation 

• Freeze/thaw 

• Wind 

• Water 

• Fire 

• Gravity 

• Mass wasting 

• Abrasion during 

transport

• Surface water 

• Soil/rock pH 

• Mineral replacement 

• Oxidation (rust, 

pyritization)

Displacement 

• Pack rats 

• Harvester ants 

Destruction/Damage 

• Burrowing organisms 

• Trampling ungulates 

• Vegetation (root and 

lichen growth)

• Construction 

(buildings, roads, dams) 

• Mining 

• Military activities 

(construction, vehicles, 

ballistics) 

• Theft/vandalism 

• Poor science and 

recovery techniques 

• Livestock 

• Agriculture 

• Recreational 

activities (offroad 

vehicle travel)

SUBSURFACE 

Physical Chemical Biological Human

Tectonics 

• Seismicity 

• Folding/faulting 

• Intrusive events 

• Metamorphism 

Weathering/Erosion 

• Freeze/thaw 

(permafrost) 

• Water movement 

(piping, cavern 

formation) 

• Gravity 

• Mass wasting 

• Compaction 

• Rockfalls

• Groundwater 

• Soil/rock pH 

• Mineral replacement 

• Metamorphism 

(partial melt, 

recrystallization)

Displacement 

• Root growth 

• Bioturbation 

Destruction/Damage 

• Burrowing organisms 

• Root growth

• Construction 

(buildings, roads, dams) 

• Mining 

• Military activities 

(construction, 

ballistics) 

• Theft/vandalism 

• Poor science and 

excavation technique 

(dynamite)

Source: Santucci and Koch (2003). 
 NPS Geologic Resources Division 14 

Figure 5. Lignite. A low-rank variety of coal called lignite is high in sulfur and prominently exposed in Theodore Roosevelt National 

Park. Burning lignite produces an interesting rock type called clinker, which is generally red in color. NPS photo by Dave Krueger. 

Figure 6. Clinker. Locally known as “scoria,” clinker is the baked residue left from burning coal seams. Outside the park clinker is used 

for road base and ornamental lawn and garden material. Bruce Heise, GRE Program Manager, is pictured above for scale. Photo by 

Katie KellerLynn. 
 THRO Geologic Resource Evaluation Report 15

Figure 7. Cap Rock. The variation in lithology of the Fort Union Group is displayed as sediments with a wide range of colors and 

weathering characteristics. The terrain along Caprock Coulee Trail in the park is studded with erosional remnants capped by resistant 

rock in many forms and sizes. NPS photo by Dave Krueger. 

Figure 8. Little Missouri River. The Little Missouri River flows through all three units of Theodore Roosevelt National Park. This 

photograph was taken near the bend below Juniper Campground in the North Unit. NPS photo by Dave Krueger. 
 NPS Geologic Resources Division 16 

Figure 9. Rotational Slump. A small rotational slump in the Sentinel Butte strata shows the failure plane abruptly merging with a thin 

bed of lignite. Source: Biek and Gonzalez (2001). 

Figure 10. Petrified Stump. The most common kind of fossil in Theodore Roosevelt National Park is petrified wood, which occurs in 

both the Sentinel Butte and Bullion Creek formations. Photo by Katie KellerLynn. 
 THRO Geologic Resource Evaluation Report 17

Figure 11. Piping. Erosional pipes form in the poorly lithified bedrock of Theodore Roosevelt National Park. The principal danger 

associated with erosional pipes is collapse. NPS photo by Dave Krueger. 

Figure12. Bentonitic Clay Overlook of the North Unit. The distinctive “blue bed” (bentonite) of the Sentinel Butte Formation can be 

traced for miles along the Little Missouri River and for some distance to the north. NPS photo by Dave Krueger. 
 NPS Geologic Resources Division 18 

Geologic Features and Processes 

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

and processes in Theodore Roosevelt National Park. 

Myriad natural features contribute to the development 

of badlands topography at Theodore Roosevelt National 

Park (figure 13). Among these factors are intense seasonal 

storms; relatively soft, easily erodible rocks; and the 

absence of dense stabilizing vegetation. Badlands 

formation is probably the most distinctive geologic 

process occurring in the park. Badlands topography is 

discussed in detail in the “Geologic Setting,” “Coal 

Resources and Mining,” and “Geologic History” 

sections. Other features and processes of the landscape 

at Theodore Roosevelt National Park are presented in 

alphabetical order here. 

Concretions and Cap Rocks 

Concretions are hard, compact aggregates of mineral 

material. They precipitate out of solution from 

groundwater. Prior to the regional erosion of the Little 

Missouri badlands, groundwater slowly seeped through 

the layers of sediments for millions of years. This water 

contained minerals, which precipitated then cemented 

around sand grains or other nucleus (e.g., shell or bone 

fragments). Some concretions are remarkably large, 

especially in the North Unit. For example, along the 

scenic drive near Squaw Creek Campground, large, 

round concretions called “cannonballs” have eroded out 

of the surrounding rock and accumulated at the base of 

the cliffs (Murphy et al. 1999). Erosion- resistant 

concretions preferentially weather out of the basal 

sandstone of the Sentinel Butte Formation. Many of 

these concretions form the resistant caprock of pedestals 

(also known as rain pillars or hoodoos). These cap rocks 

are flat, hard, sandstone slabs that protect the underlying 

sediments from erosion. Eventually the slabs will tilt or 

fall off the pedestals and the remaining soft sediments 

will quickly erode away (Murphy et al. 1999). 

Glacial Erratics 

Large boulders once transported by glaciers now rest 

scattered on bedrock surfaces different from their own 

compositions, a position which testifies to the 

effectiveness of glacial erosion and transport. Many 

erratics have glacial striations or scratches that formed as 

they were dragged against bedrock during glacial 

movement. Glacial erratics of granitic and carbonate 

compositions are the primary evidence of glaciation in 

Theodore Roosevelt National Park (Biek and Gonzalez 

2001). They occur in the North Unit and are thought to 

mark the maximum extent of glacial ice in this part of the 

Missouri Plateau. Most of the erratics are 1 to 2 feet (0.3 

to 0.6 m) in diameter, but some are almost 5 feet (1.5 m) in 

diameter (Biek and Gonzalez 2001). 

Eolian Deposits 

Windblown deposits such as loess and sand cover large 

areas of the Great Plains. This wide eolian distribution 

throughout the region was recognized almost as soon as 

geological exploration began in the late 19th century 

(Emmons et al. 1896; Gilbert, 1896). Though sporadically 

mapped and underrepresented on most geologic maps, 

investigators of Quaternary climate change have renewed 

scientific interest in loess and eolian sand (Madole 1995). 

Lengthy loess sequences, such as those present on the 

northern Great Plains, contain detailed records of 

Quaternary glacial- interglacial cycles. Scientists consider 

these to be a terrestrial equivalent to the foraminiferal 

oxygen isotope record of deep- sea sediments, which 

document long- term climate change (Muhs et al. 1999). 

Loess is also a direct record of atmospheric circulation. 

Information on paleowind from loess in the geologic 

record can test atmospheric general circulation models 

(Muhs et al. 1999). In addition, widespread eolian 

deposits are important sources of information for 

reconstructing the history of aridification in the interior 

of North America during the Quaternary (Madole 1995). 

In North Dakota, sediments deposited during the 

Pleistocene Epoch (1.8 million years ago to 11,800 years 

ago) belong to what geologists call the Coleharbor 

Group. Sediments deposited during the Holocene Epoch 

(11,800 years ago to present) belong to the Oahe 

Formation. Loess is present in both of these units. 

Although most upland surfaces are veneered with loess, 

and dune sands are locally present, neither were mapped 

by Biek and Gonzalez (2001). Loess is difficult to map 

where it is thin (less than 5 feet [1.5 m]) or overlies rocks 

that weather to residuum that is texturally similar to 

loess, as is the case in much of the badlands region 

(Madole 1995). 

Oxbows 

The erosion and deposition of sediments associated with 

active streams constantly change riparian ecosystems. In 

the valleys at Theodore Roosevelt National Park, streams 

tend to meander—widening their bends and occasionally 

short- circuiting them. This leaves the abandoned 

meanders as oxbow lakes, which slowly fill in with 

sediment (figure 14). Remnants of these filled lakes 

record this process as ongoing along the Little Missouri 

River (Laird 1956). Today, the Little Missouri River 

makes a wide bend as it turns east in the North Unit. 

Eventually, the river will abandon the large U- shaped 

portion of the channel in favor of a more direct route, 

leaving a stranded oxbow (Murphy et al. 1999). 
 THRO Geologic Resource Evaluation Report 19

Pediments 

Pediments are broad, erosional, low- angle bedrock 

surfaces, extending out from highland margins. They are 

correlative with arid and semiarid conditions and are 

associated with landscape development over time. 

However, the connection between pediments and 

climate is still a subject of debate among 

geomorphologists (Summerfield 1991). 

In Theodore Roosevelt National Park pediments occur 

at the bases of major escarpments and the heads of major 

drainages. In the South Unit, the largest pediment 

surfaces are located at the foot of the eastern 

escarpment, in the vicinity of Boicourt and Sheep Butte 

springs, and at the heads of Sheep, Paddock, and Jones 

creeks. In the North Unit, large pediments occur along 

Squaw Creek and the Little Missouri River (Biek and 

Gonzalez 2001). Pediments in the park are complex 

assemblages in which erosional surfaces have been 

buried by sheetwash sediment or reworked eolian 

material (see “Sheetwash Erosion” and “Eolian 

Deposits” sections). These conditions make 

interpretation and study of landscape development via 

pediments difficult in the park. 

Sand and Gravel 

Sand and gravel are present in alluvial deposits (units 

QTa and Qt on the geologic map) in the North and South 

units of Theodore Roosevelt National Park. These 

deposits occur as a veneer capping high- level plateaus 

near the Little Missouri River. A thick mantle of 

Holocene loess often covers these deposits. 

Sand and gravel have been mined by private entities from 

at least two places inside park boundaries. The first 

location, at the eastern edge of the Petrified Forest 

Plateau, probably provided sand and gravel for road 

material (used locally) and the trail leading to the top of 

Petrified Forest Plateau (Biek and Gonzalez 2001). In 

2002 the National Park Service acquired the second 

location—a 5,510- acre (2,230 ha) land acquisition 

containing 960 acres (389 ha) of sand and gravel 

potential. This property was previously owned by Ken 

and Norma Eberts who periodically sold gravel from the 

site to Billings County for road improvements. The 

National Park Service extinguished sand and gravel 

rights in conjunction with the buyout of the parcel of 

land (Phil Cloues, NPS Geologic Resources Division, 

written communication, October 18, 2004). 

Sometime before 1957, sand and gravel deposits were also 

mined from another location atop the plateau 

immediately east of Medora. This currently unreclaimed 

pit is located just outside the park’s boundary. A large 

landslide is present on the steep slope just west of the pit 

(Biek and Gonzalez 2001). 

Sandstone and Silcrete 

During the 1930s, the Civilian Conservation Corps used 

medium- grained, cross- bedded sandstone from a 

quarry near Theodore Roosevelt National Park to 

construct various structures in the park. For example, 

rough blocks of what is likely Sentinel Butte sandstone 

surround the perimeter of the shelter at the Riverbend 

Overlook in the North Unit (figure 15). Large blocks of 

the same sandstone and silcrete blocks of the Taylor bed 

(upper unit of the Bear Den Member of the Golden 

Valley Formation) line the path down to the shelter. 

Silcrete is silica- cemented sand and gravel. Investigators 

are uncertain whether these stones were quarried in the 

park. A 1937 photo caption implies that the quarry was in 

the North Unit, but a longtime park employee was 

certain that the quarry was located 25 miles (40 km) 

southwest of the park in an area called Flat Top Butte 

(Biek and Gonzalez 2001). At present, investigators have 

not seen any evidence of sandstone quarrying within 

Theodore Roosevelt National Park (Biek and Gonzalez 

2001). 

In 1938, the Emergency Relief Association built the old 

South Unit entrance station. This check station, adjacent 

stone fence, and privy are made from cut and dressed 

sandstone blocks of unknown origin. A pylon 

constructed of this same stone upon which the park’s 

name hangs was originally at the check station. It was 

moved to the Painted Canyon Visitor Center in 1968 

(Biek and Gonzalez 2001). 

Sheetwash Erosion 

In densely vegetated environments, the presence of 

stabilizing plant roots usually prevents rills from 

developing. By contrast, in arid and semiarid 

environments such as Theodore Roosevelt National 

Park, where precipitation tends to fall in intense bursts, 

erosional features such as rills and gullies naturally 

develop. The slopes of many of the buttes in the park are 

extremely gullied or minutely dissected by running 

water. Rill- and- gully erosion occurs particularly in the 

basal sandstone of the Sentinel Butte Formation. 

The movement of water across a slope surface is called 

sheetwash. This is a general term because, unlike a sheet, 

water flow is never of uniform depth due to 

microtopography of hillslope surfaces. Sheetwash 

typically grades into channelized flow as the water 

movement becomes progressively more concentrated 

into particular downslope routes. For this reason, the 

distinction between “sheet flow” and “channelized flow” 

is sometimes indefinite. Nevertheless, sheetwash flowing 

from the sides of a butte in the badlands will typically 

concentrate into tiny rills as a result of irregularities of 

the slope. Some of these rills break down between 

rainfall events; others enlarge into gullies that deepen 

and widen with each rain. As rills develop into gullies, 

they erode back into the butte until two rivulets meet at 

their heads. The divide between them becomes very 

narrow and more succeptible to rapid weathering and 

erosion. Eventually, the divide between the two rivulets 

degrades entirely, separating a small portion of the butte 

side from the main butte. Thus, the butte erodes 

incrementally by both the action of running water and by 

this process of segmentation (Laird 1956). 
 NPS Geologic Resources Division 20 

Terraces 

Changes in channel gradient, discharge, or sediment load 

can cause a river to incise its floodplain and form 

terraces. River terraces also can be cut into previously 

deposited alluvium or bedrock. Following incision, the 

original floodplain is abandoned and left as a relatively 

flat bench (terrace), which is separated from the new 

floodplain below. River terraces are inclined 

downstream but not always at the same angle as the 

active floodplain. The valley wall of an entrenching river 

may contain a vertical sequence of terraces. The lowest, 

youngest terrace may retain traces of floodplain 

morphology, whereas the highest, oldest terrace may be 

heavily weathered. Terraces can be either paired or 

unpaired. Paired terraces on opposite sides of the river 

form when vertical incision occurs more rapidly than the 

lateral migration of the channel. Unpaired terraces form 

when rapid lateral shifting of the channel occurs and the 

river cuts terraces alternately on each side of the valley 

floor. 

In general, geomorphologists differentiate terraces and 

assign ages based on height above the modern stream 

level. For example, in the South Unit, alluvial terrace 

deposits (unit Qt on the geologic map) are subdivided 

into four mappable units (from youngest to oldest): Qt1, 

Qt2, Qt3, and Qt4. 

Terraces in Theodore Roosevelt National Park record 

changes caused by a major climatic cooling event during 

the Pleistocene Epoch. This cooling caused the advance 

of large continental ice sheets from northern latitudes. In 

pre- glacial time, the Little Missouri River flowed north 

toward Hudson Bay. However, when glaciers advanced 

southward, local north- flowing streams were blocked; 

the drainages of the Little Missouri and Yellowstone 

rivers were diverted along the edge of the ice front. This 

ice- marginal drainage eventually became the present 

Missouri River, which the Little Missouri River flows 

into. The rate of erosion and downcutting of the Little 

Missouri River was not constant: as erosion and 

deposition continued, the river cut a series of terraces, 

remnants of which can be seen in the park (Harris and 

Tuttle 1990). 
 THRO Geologic Resource Evaluation Report 21

Figure13. View of Badlands from Oxbow Overlook. Theodore Roosevelt National Park is an ideal setting for the development of 

badlands topography. Badlands formation with its high-drainage density is probably the most distinctive geologic process in the park. 

NPS photo by Dave Krueger. 
 NPS Geologic Resources Division 22 

Figure 14. Oxbow Overlook. The Little Missouri River makes a huge bend as it turns east in the North Unit. Eventually, the river will 

abandon the large U-shaped portion of the channel and flow in a more direct course, leaving an oxbow. NPS Photo by Dave Krueger. 

Figure 15. Shelter at Riverbend Overlook. The Civilian Conservation Corps used medium-grained, cross-bedded sandstone from a 

local quarry to construct various structures in the park, such as this shelter in the North Unit. NPS photo by Dave Krueger. 
 THRO Geologic Resource Evaluation Report 23

Map Unit Properties 

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

map of Theodore Roosevelt National Park. The table is highly generalized and is 

provided for informational purposes only. Ground disturbing activities should not be 

permitted or denied on the basis of information contained in this table. More detailed 

unit descriptions can be found in the help files that accompany the digital geologic map 

or by contacting the NPS Geologic Resources Division. 

The GRE Program created digital geologic data and a 

helpfile from the map booklet of The Geology of Theodore 

Roosevelt National Park by R. F. Biek and M. A. 

Gonzalez. Detailed descriptions of the map units and 

discussions of mineral resources and geologic hazards 

are provided in the booklet portion of that publication. 

The following table summaries the map units of Biek and 

Gonzalez (2001). It presents an itemized list of features 

for each map unit: age, unit name and map symbol, 

location in the park, description, depositional setting, 

local and global significance, limits for development and 

recreation, and resource potential (e.g., paleontological, 

water, and mineral resources). 
Map Unit Properties Table 

Age Map Unit (Symbol) Park Location (unit) Description Depositional Setting Loc

Engineering fill (Qef) 

North and South units Used in road construction Roads, bridges, and built up areas (shown on topographic base map) 

Modern alluvium 

(Qal) 

North and South units 

Sand, silt, clay, & gravel, younger than 500 years old; includes alluvium under modern floodplain & lowest terrace surface; shallow aquifer 25–200 ft (7–61 m) 

Modern stream channels, floodplain, and beneath low stream terraces 

Part of Oahe during the Ho

Older alluvium 

(Qoal) 

North and South units 

Sand, silt, clay, and gravel; distinguished from modern alluvium (Qal) by steep, typically vertical, erosion scarp; 

≤20 ft (6 m) thick 

Stream deposits beneath Holocene terraces Part of Oahe 

during the Ho

Alluvial fan deposits (modern) (Qf1) 

Alluvial fan 

deposits (Qf) Alluvial fan deposits (older) 

(Qf2) 

North and South units; in South Unit only, differentiated on map into modern and older units 

Highly variable sequence—ranging from coarse and poorly sorted sand and gravel to massive or laminated mud; typically consists of locally derived material, except for largest fans of largest tributaries Older fans—deeply incised and no longer receive sediment from their contributory streams 

Present at the mouths of nearly every small valley but only the larger fans along the Little Missouri River and its major tributaries were mapped (Biek and Gonzalez, 2001) 

Part of Oahe during the Ho

Mantled pediments 

(Qmp) 

North and South units 

Complex assemblage of active and incised alluvial deposits of sand, silt, and clay; mantle 

≤3 ft (0.9 m) 

thick but may exceed 6 ft (1.8 m) in places 

Erosional surfaces formed during arid and semiarid conditions; mantled with eolian and sheetwash deposits 

Part of Colehsediments deHolocene epo

Landslide deposits 

(Qls) 

North and South units 

Locally derived sediment; commonly rotational slumps; characterized by hummocky topography, numerous arcuate scarps, and chaotic bedding 

Transported principally by gravity (e.g., slump, earth flow, rockfall, and creep) to hillsides and valley floors 

Quaternary 

(Pleistocene and Holocene) 

Unconformity 

Qt1 Qt1—at 2,400 ft (732 m) above sea level, 160 ft (49 m) above modern drainage Qt2 Qt2—at 2,460 ft (750 m) above sea level, 220 ft (67 m) above modern drainage Qt3 Qt3—at 2,480 ft (756 m) above sea level, 240 ft (73 m) above modern drainage 

Alluvium beneath 

Pleistocene terraces 

(Qt) 

Qt4 

North and South Units; in South Unit differentiated into four map units by height above modern channel 

Sand and gravel atop plateaus, mesas, buttes, ridges, and benches flanking Little Missouri River valley; resembles QTa but 170–240 ft (52–73 m) below QTa deposits; 

≤6 ft (1.8 m) thick; mantled by Holocene 

loess (not mapped); Qt4—highest and oldest Pleistocene terrace Qt4—at 2,500 ft (762 m) above sea level, 260–270 ft (79–82 m) 

above modern drainage 

Part of the Codeposited duand gravel (

≤5 

Glacial erratics (Qg) North Unit 

Widely scattered granitic and carbonate boulders and cobbles; most are 1–2 ft (0.3–0.6 m) in diameter but some as large as 5 ft (1.5 m) 

Deposited at maximum extent of glacial ice 

Only evidencColeharbor Gthe Pleistocen

Unconformity 

Quaternary 

 (Pleistocene) 

Upland gravel (QTa) North and South units Sand and gravel, underlain by loess; contains pebbles and cobbles of well- cemented, locally derived materials; 

≤5 ft (1.5 m) thick 

Stream deposits (terraces) 

Uncertain codeposits, likearea; Biek and indeterminat

Unconformity 

Golden Valley Formation, Bear Den Member, Taylor bed silcrete lag (Tsbsl) 

North Unit, Achenbach Hills only 

Silcrete (silica- cemented) blocks up to 10 ft (3 m) square and 2 ft (0.6 m) thick, most are about 1 ft (0.3 m) thick; lag deposit; forms a pavement 

Swamp or marsh; a weathering horizon indicates hiatus in deposition 

Sentinel Butte Formation (Tsb) 

North and South units 

Grayish brown siltstone, claystone, sandstone, and 

lignite; includes basal sandstone, 1 or 2 petrified wood horizons (depending on location), bentonite (“blue bed”) layer, and siltstone (lower and upper yellow beds); forms hoodoos 

River, lake, and swamp environments; ash source from 250 mi (400 km) away; nearly complete section exposed in North Unit (760 ft [232 m]); lower 300 ft (91 m) exposed in South Unit 

The most widmost widesprformation in lignite) importopography 

Tertiary 

(Paleocene) 

Fort Union Group Bullion Creek Formation 

(Tbc) 

South Unit 

Bright yellowish brown siltstone, claystone, and sandstone; differentiated from Sentinel Butte Formation by (1) stratigraphic position with respect to the HT Butte lignite or clinker between the two units, and (2) color (brighter = Bullion Creek) 

River, lake, and swamp environments 

Fort Union G

sediment eroLaramide Oro
 THRO Geologic Resource Evaluation Report 25

Geologic History 

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

in Theodore Roosevelt National Park and puts them in a geologic context in terms of the 

environment in which they were deposited and the timing of geologic events that 

ultimately created the present landscape. 

Pre-Paleocene 

The geologic features displayed in Theodore Roosevelt 

National Park are primarily Paleocene and younger in 

age (≤65 million years old). However, the geologic story 

of the area begins much earlier. The older rocks buried 

deep beneath the park contain significant natural 

resources such as oil and gas, which are extracted from 

Pennsylvanian, Mississippian, Devonian, and Ordovician 

rocks (see table 1) in the Williston Basin. The Williston 

Basin is a large, roughly circular depression on the North 

American craton covering several hundred thousand 

square miles across parts of North and South Dakota, 

Montana, and the Canadian provinces of Manitoba and 

Saskatchewan. The Williston Basin began subsiding 

during the Ordovician Period. Although the Williston 

Basin was subsiding, marine sediments were not 

continuously deposited in it. Nevertheless, the basin 

contains an unusually complete rock record compared to 

many basins; some rocks from each Phanerozoic period 

are preserved there. These strata record several cycles of 

marine transgressions that filled the basin, followed by 

marine regressions that drained it. In all, more than 

16,000 feet (4,800 m) of sediments, mostly shallow 

marine but also some terrestrial deposits, settled into the 

Williston Basin. 

The early structural history of the basin is poorly 

understood (Heck et al. 2002). The earliest rocks are 

difficult to study because the Lower Phanerozoic and 

Precambrian (see table 1) rocks are not exposed at the 

surface in North Dakota and only a few wells have 

penetrated these rocks. Present understanding of the 

early geologic history of the basin is pieced together from 

outcrops in adjacent states and provinces, seismic data, 

and limited well data (Heck et al. 2002). 

During the Cretaceous, an inland sea covered the interior 

of the continent and more marine sediments collected. 

The Cretaceous Interior Seaway was hundreds of miles 

wide and divided North America into two separate land 

masses. The northwest- southeast oriented 

epicontinental seaway stretched from the Arctic Ocean 

to the Gulf of Mexico. The sea retreated from most of 

the continent by about 65 million years ago. Coincident 

with this marine regression, the Laramide Orogeny 

uplifted the Rocky Mountains hundreds of miles west of 

the park. Uplift produced hundreds of cubic miles of 

sediment that eroded from the newly formed mountains. 

Streams carried this sediment eastward and deposited it 

in great clastic wedges across the Great Plains. A thick 

sequence of terrestrial sediments, which ranges in age 

from Late Cretaceous through Oligocene, records this 

event in many parts of the Dakotas and Montana. 

Paleocene 

In North Dakota and Theodore Roosevelt National 

Park, the Fort Union Group represents the Paleocene 

portion of the clastic wedge, which sloped eastward from 

the Rocky Mountains. The exact depositional setting of 

the Fort Union Group has been the subject of some 

debate. The sediments of the Fort Union Group were 

deposited on what various investigators have called an 

“alluvial plain” (Laird 1956), a “meandering fluvial 

channel system” (Fastovsky and McSweeney 1991), and a 

“broad sea- level delta” (Theodore Roosevelt National 

Park Web site, accessed October 25, 2004). Regardless of 

the specific geomorphic setting, water was apparently 

ubiquitous in time and space. Thus a reasonable 

interpretation for the general environment is a lowlying, swampy region in which water- loving trees and 

other plants grew. 

As leaves, branches, and entire dead trees fell into the 

stagnant waters of the swamps, they eventually became 

peat as bacteria only partially decomposed them and as 

additional sediments compressed the organic material. 

Streams continued to deposit more and more sediment 

in the area, creating lignite. If more pressure had been 

applied, bituminous (soft) coal would have eventually 

formed. A total thickness of about 1,350 feet (410 m) of 

sediment was deposited during the Paleocene Epoch, 

forming the 600- foot- (180 m) thick Bullion Creek 

Formation and the 750- foot- (230 m) thick Sentinel 

Butte Formation. 

Also, during this time, volcanoes punctuated the 

landscape of the western United States. Rivers and winds 

transported the erupted ash into North Dakota. Along 

with other sediments and organic material, this ash 

accumulated in standing water. Silica (quartz) from these 

ash deposits played a major role in the petrifaction of 

cypress, sequoia, and other deciduous and cone- bearing 

trees that grew in the low- lying, subtropical 

environment. Few representative fossil- leaf locales are in 

the park, so investigators have interpreted the existence 

of various species from a fossil site called Wannagan 

Creek. This site is in the Bullion Creek Formation and is 

located just to the west of the South Unit (John 

Hoganson, North Dakota Geological Survey, written 

communication, December 7, 2004). Groundwater 

moving through the silica- rich volcanic ash dissolved the 

silica. When this silica- saturated water soaked into the 

trees, microcrystalline material replaced the organic 
 NPS Geologic Resources Division 26 

compounds in the wood. In some cases, the internal 

structures of the trees including growth rings were 

preserved in stone. In addition to allowing petrifaction of 

wood, the Paleocene ash layers formed the bentonite 

“blue beds,” which now contribute to the scenic 

badlands topography in the park. 

Post-Paleocene 

Scattered remnants of post- Paleocene sediments are 

present throughout western North Dakota as isolated 

caps on buttes. These units, including the Golden Valley 

Formation and the White River Group, were deposited 

during the Eocene and Oligocene epochs (56–23 million 

years ago). In the park, a lag deposit composed of silcrete 

called the Taylor bed (the upper portion of the Bear Den 

Member of the Golden Valley Formation), caps the 

Archenbach Hills of the North Unit. Geologists interpret 

this lag deposit as a weathering horizon developed on 

top of the Sentinel Butte Formation (Clayton et al. 1980). 

The weathering horizon marks a hiatus in deposition, 

called an unconformity, between the Bear Den Member 

and the overlying Camels Butte Member (Biek and 

Gonzalez 2001). This silcrete lag contains only silica- rich 

chert and lacks lithic fragments such as feldspar and 

other readily weathered minerals. This composition 

suggests that resistant quartz was all that remained after a 

prolonged period of weathering (Hickey 1977). 

As a result of intense long- term weathering and erosion, 

no bedrock units in western North Dakota are younger 

than Oligocene in age. Accumulations of gravel and sand 

(e.g., unit QTa on the geologic map) are difficult to date 

but provide the only evidence of deposition subsequent 

to Oligocene time. Post- Laramide regional uplift at the 

end of the Paleocene Epoch caused a change in regional 

base level, forcing streams to incise their channels. For 

millions of years, streams had been depositing sediment 

nearly continuously on the Great Plains. In western 

North Dakota the uplift caused the rivers ancestral to the 

modern Little Missouri River system to dissect the 

plains, incising and eroding away much of the poorly 

consolidated upper rock layers. Huge volumes of 

sediment from the northern Great Plains were carried 

towards Hudson Bay. 

Pleistocene 

After much incision, river channel courses were firmly 

established at the beginning of the Pleistocene Epoch (1.8 

million years ago). At the same time global climate 

changes triggered the advance of great ice sheets from 

the north. These continental glaciers formed, advanced, 

and retreated many times during the Pleistocene Epoch. 

Glacial erratics in the North Unit record the farthest 

local extent of glacial advance onto the Missouri Plateau. 

The glacial effects in this area are not particularly 

pronounced; classic glacial features such as moraines do 

not appear in this landscape. However, glacial effects 

were significant with respect to the changes made to 

regional drainage patterns. These changes strongly 

influenced the recent geology of Theodore Roosevelt 

National Park (Laird 1956). 

Before the initial advance of continental ice sheets, the 

Missouri River flowed northeastward into Canada and to 

Hudson Bay (figure 16). Its major tributaries, the 

Yellowstone and Little Missouri rivers, joined the 

Missouri in northwestern North Dakota. The eastflowing Knife, Heart, and Cannonball rivers in North 

Dakota also joined a stream that flowed northward to 

Hudson Bay (Trimble 1993). When continental ice sheets 

advanced southward from Canada and reached as far as 

the upper North Unit in the park, the ice blocked the 

courses of these north- flowing rivers. This forced them 

to create new routes eastward and southward, thereby 

emptying into the Mississippi River instead of Hudson 

Bay. 

According to Biek and Gonzalez (2001), glacial diversion 

of the Little Missouri River occurred by mid- Pleistocene 

time, at least 640,000 years ago, though the exact timing 

is uncertain. Nevertheless, by the time the ice sheet 

retreated, the northern portions of both the Little 

Missouri and Missouri rivers were entrenched into new 

channels. The new route of the northern Little Missouri 

River followed a steeper course, causing the whole river 

to flow faster and begin downcutting rapidly into the 

layered sediments. Because the elevation of the mouth of 

the Little Missouri was now considerably lower than it 

had been before joining the Yellowstone River (just east 

of present- day Williston), it eroded quickly through the 

soft sedimentary rocks. As the river began rapid incision, 

its tributaries also began cutting gullies on a grand scale, 

carving the fantastically broken topography of the 

badlands. In addition, as streams eroded the poorly 

consolidated sediments, many valley walls became oversteepened and unstable. The presence of bentonite 

exacerbated this situation. These slopes often failed 

causing landslides. The most spectacular landslides are 

those in the North Unit, where two classic types of 

rotational slumps are present (see “Mass Wasting” 

section). 

The rate of erosion and incision of the Little Missouri 

River was not constant. As intermittent erosion and 

deposition continued, the stream cut a series of four 

terraces, the remnants of which can still be seen in the 

park (Harris and Tuttle 1990). The complicated story 

recorded in these terraces is still unclear, and the lack of 

reliable radiometric dates has lead to various mapping 

styles and nomenclature for these deposits (Biek and 

Gonzalez 2001). Correct geomorphic interpretation of 

these terraces is significant for completely understanding 

(1) when the ancestral Little Missouri River occupied the 

highest terrace level, (2) the exact timing of drainage 

diversion of the ancestral Little Missouri River, (3) the 

timing of inception of incision of badlands erosion, and 

(4) the rate of formation of badlands topography. 

Holocene 

In the past 11,800 years, various geologic processes that 

began during the Pleistocene have continued. This 

includes the formation of badlands topography, mass 

wasting, and the formation and mantling of pediments 

(see “Mass Wasting” and “Pediments” sections). 
 THRO Geologic Resource Evaluation Report 27

However, three types of deposits in the park are 

exclusively Holocene in age: alluvial fans, various 

alluvium (units Qoal and Qal on the geologic map), and 

engineered fill. Alluvial fans are present at the mouths of 

nearly every small valley in the park where they mingle 

with stream deposits. The upstream portion of alluvial 

fans is gradational, interfingering with sheetwash and 

colluvial deposits that mantle valley margins. Other 

alluvial deposits of Holocene age are found along stream 

channels show that most streams have been aggrading 

for the past 150 years or more, but the upper reaches have 

incised during this same period (Biek and Gonzalez 

2001). Finally, some areas of engineered fill occur in the 

park: along U.S. Route 85 in the North Unit and along I94 in the South Unit. These mappable units show that 

humans are agents of landscape change. 

Figure 16. Pre- and Post-Glacial Drainages of North Dakota. A. Rivers flowed north into Canada and northeast to Hudson Bay before glaciers 

diverted them. B. Glacial diversion caused the rivers to change direction. Source: Murphy et al. (1999). 
 NPS Geologic Resources Division 28 

Glossary 

This glossary contains brief definitions of technical geologic terms used in this report. Not all 

geologic terms used are referenced. For more detailed definitions or to find terms not listed 

here please visit http://wrgis.wr.usgs.gov/docs/parks/misc/glossarya.html. 

alluvial fan. A fan- shaped deposit of sediment that 

accumulates where a high- gradient stream flows out 

of a mountain front into an area of lesser gradient such 

as a valley. 

alluvium. Stream- deposited sediment that is generally 

rounded, sorted, and stratified. 

aquifer. Rock or sediment that is sufficiently porous, 

permeable, and saturated to be useful as a source of 

water. 

ash (volcanic). Fine pyroclastic material ejected from a 

volcano. 

base level. The lowest level to which a stream can erode 

its channel. The ultimate base level for the land surface 

is sea level, but temporary base levels may exist locally. 

basin (structural). A doubly plunging syncline in which 

rocks dip inward from all sides. 

basin (sedimentary). Any depression, from continental 

to local scales, into which sediments are deposited. 

bed. A “unit” of sedimentary strata commonly ranging in 

thickness from one centimeter to a meter or two and 

distinguishable from beds above and below. 

bedding. Depositional layering or stratification of 

sediments. 

block (fault). A crustal unit bounded by faults, either 

completely or in part. 

cementation. Chemical precipitation of material into 

pores between grains that bind the grains into rock. 

chemical weathering. The dissolution or chemical 

breakdown of minerals at Earth’s surface via reaction 

with water, air, or dissolved substances. 

clastic. Rock or sediment made of fragments or 

preexisting rocks. 

clay. Clay minerals or sedimentary fragments the size of 

clay minerals (<1/256 mm). 

craton. The relatively old and geologically stable interior 

of a continent. 

crystalline. A regular, orderly, repeating geometric 

arrangement of atoms. 

dip. The angle between a structural surface and a 

horizontal reference plane measured normal to their 

line of intersection. 

drainage basin. The total area from which a stream 

system receives or drains precipitation runoff. 

dune. A low mound or ridge of sediment, usually sand, 

deposited by wind. Common dune types include the 

barchan dune, longitudinal dune, parabolic dune, and 

transverse dune. 

eolian. Formed, eroded, or deposited by or related to the 

action of wind. 

ephemeral stream. A stream that flows only in direct 

response to precipitation. 

fault. A subplanar break in rock along which relative 

movement occurs between the two sides. 

feldspar. A group of abundant rock- forming minerals. 

Feldspars are the most widespread of any mineral 

group and constitute 60% of Earth’s crust. They occur 

in all types of rocks. Feldspars are white and gray to 

pink, have a hardness of 6, are commonly twinned. 

formation. Fundamental rock- stratigraphic unit that is 

mappable and lithologically distinct from adjoining 

strata and has definable upper and lower contacts. 

fracture. Irregular breakage of a mineral; also any break 

in a rock (e.g., crack, joint, or fault) 

hoodoo. Pillars developed by erosion of horizontal strata 

of varying hardness. Typically found in climatic zones 

where most rainfall is concentrated during a short 

period of the year. 

igneous. Refers to a rock or mineral that originated from 

molten material; one of the three main classes or rocks: 

igneous, metamorphic, and sedimentary. 

karst topography. A landscape characterized by 

abundant sinkholes and caverns formed by the 

dissolution of calcareous rocks. 

landslide. Any process or landform resulting from rapid 

mass movement under relatively dry conditions. 

lava. Magma that has been extruded onto Earth’s 

surface, both molten and solidified. 

lithification. The conversion of sediment into solid rock. 

lithology. The description of a rock or rock unit, 

especially the texture, composition, and structure of 

sedimentary rocks. 

loess. Silt- sized sediment deposited by wind. 

meanders. Sinuous lateral curves or bends in a stream 

channel. 

mechanical weathering. The physical breakup of rocks 

without change in composition (syn: physical 

weathering). 

member. A lithostratigraphic unit with definable contacts 

that subdivides a formation. 

mesa. A broad, flat- topped erosional hill or mountain 

that is bounded by steeply sloping sides or cliffs. 

metamorphism. Literally “change in form.” 

Metamorphism occurs in rocks with mineral 

alteration, genesis, or recrystallization from increased 

heat and pressure. 

mineral. A naturally occurring, inorganic crystalline solid 

with a definite chemical composition or compositional 

range. 

orogeny. A mountain- building event, particularly a wellrecognized event in the geological past (e.g., the 

Laramide Orogeny). 

outcrop. Any part of a rock mass or formation that is 

exposed or “crops out” at Earth’s surface. 

overburden. Non- economic, often unconsolidated, rock 

and sediment overlying an ore, fuel, or sedimentary 

deposit. 
 THRO Geologic Resource Evaluation Report 29

paleontology. The study of the life and chronology of 

Earth’s geologic past based on the phylogeny of fossil 

organisms. 

pediment. A gently sloping, erosional bedrock surface at 

the foot of mountains or plateau escarpments. 

plateau. A broad, flat- topped topographic high of great 

extent and elevation above the surrounding plains, 

canyons, or valleys (both land and marine landforms). 

potash. An impure form of potassium carbonate (K2CO3) 

mixed with other potassium salts. Potash has been 

used since antiquity in the manufacture of glass and 

soap, and as a fertilizer. 

regression. A long- term seaward retreat of the shoreline 

or relative fall of sea level. 

rill. One of the first and smallest channels formed by 

runoff. 

rock. A solid, cohesive aggregate of one or more 

minerals. 

sandstone. Clastic sedimentary rock of predominantly 

sand- sized grains. 

scarp (or escarpment). A steep cliff or topographic step 

resulting from vertical displacement on a fault or by 

mass movement. 

sediment. An eroded and deposited, unconsolidated 

accumulation of lithic and mineral fragments. 

sedimentary rock. A consolidated and lithified rock 

consisting of detrital or chemical sediment(s). 

shale. A clastic sedimentary rock made of clay- sized 

particles that exhibit parallel splitting properties. 

silt. Clastic sedimentary material intermediate in size 

between fine- grained sand and coarse clay (1/256–1/16 

mm). 

siltstone. A variable lithified sedimentary rock with siltsized grains. 

slope. The inclined surface of any geomorphic feature or 

rational measurement thereof (syn: gradient). 

slump. A generally large, coherent mass movement with 

a concave- up failure surface and subsequent 

backward rotation relative to the slope. 

soil. Surface accumulation of weathered rock and 

organic matter capable of supporting plant growth and 

often overlying the parent rock from which it formed. 

spring. A site where water flows out at the surface as a 

result of the water table intersecting the ground 

surface. 

strata. Tabular or sheet- like masses or distinct layers of 

rock. 

stratigraphy. The geologic study of the origin, 

occurrence, distribution, classification, correlation, 

and age of rock layers, especially sedimentary rocks. 

stream. Any body of water moving under gravity flow 

and confined within a channel. 

subsidence. Sinking or depression of part of Earth’s 

surface. 

tectonic. Relating to large- scale movement and 

deformation of Earth’s crust. 

terraces (stream). Step- like benches surrounding the 

present floodplain of a stream due to dissection of 

previous floodplain(s), streambed(s), or valley floor(s). 

terrestrial. Relating to Earth or Earth’s dry land. 

topography. The general morphology of Earth’s surface 

including relief and location of natural and 

anthropogenic features. 

trace fossils. Evidence of organisms’ life activities, rather 

than the organisms themselves, such as tracks, root 

casts, nests, chew marks on fossil leaves, and fossilized 

dung. 

transgression. Landward migration of the sea due to a 

relative rise in sea level. 

trend. The direction or azimuth of elongation or a linear 

geological feature. 

unconformity. A surface within sedimentary strata that 

marks a prolonged period of erosion or no deposition. 

uplift. A structurally high area in Earth’s crust, produced 

by tectonic movement that raises the rocks. 

volcanic. Related to volcanoes; describes igneous rock 

crystallized at or near Earth’s surface (e.g., lava). 

water table. The upper surface of the saturated (phreatic) 

zone. 

weathering. The set of physical, chemical, and biological 

processes by which rock is broken down in place.
 NPS Geologic Resources Division 30 

References 

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

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

Biek, R. F., and M. A. Gonzalez. 2001. The geology of 

Theodore Roosevelt National Park, Billings and 

McKenzie counties, North Dakota. Miscellaneous Series 

86, text (74 p.), 2 pls. (scale 1:24,000). Bismarck: North 

Dakota Geological Survey. 

Bluemle, J. P. 1988. North Dakota clinker. NDGS 

Newsletter December 1988:29–34. 

Clayton, L., with assistance from S. R. Moran, J. P. 

Bluemle, and C. G. Carlson. 1980. Geologic map of 

North Dakota. Special Geologic Map (scale 1:500,000). 

Washington, D.C.: U.S. Geological Survey. 

Department of Energy. 1993. The fire below: 

Spontaneous combustion in coal. Environment Safety 

and Health Bulletin EH- 93- 4, DOE/EH- 0320, issue 

93- 4 (May 1993). 

http://www.saftek.net/worksafe/bull94.txt (accessed 

April 18, 2007). 

Emerson, D. G., and K. M. Macek- Rowland. 1986. Flood 

analysis along the Little Missouri River within and 

adjacent to Theodore Roosevelt National Park, North 

Dakota. Water Resources Investigations Report 86-

4090. Washington, D.C.: U.S. Geological Survey. 

Emmons, S. F., W. Cross, and G. H. Eldridge. 1896. 

Geology of the Denver Basin in Colorado. Monograph 

27. Washington, D.C.: U.S. Geological Survey. 

Fastovsky, D. E., and K. McSweeney. 1991. Paleocene 

paleosols of the petrified forest of Theodore Roosevelt 

National Park, North Dakota: A natural experiment in 

compound pedogenesis. Palaios 6:67–80. 

Fowells, H. A. 1965. Silvics of the forest trees of the 

United States. In Agriculture Handbook 271. 

Washington, D.C.: U.S. Department of Agriculture. 

Gerhard, L. C., S. B. Anderson, J. A. Lefever, and C. G. 

Carlson. 1982. Geological development, origin, and 

energy mineral resources of Williston Basin, North 

Dakota. The American Association of Petroleum 

Geologists Bulletin 66(8):989–1020. 

Gilbert, G. K. 1896. The underground water of the 

Arkansas Valley in eastern Colorado. In 17th Annual 

Report, pt. 2, 551–601. Washington, D.C.: U.S. 

Geological Survey. 

Harris, A. G., and E. Tuttle. 1990. Geology of national 

parks, 4th ed. Dubuque, IA: Kendall/Hunt Publishing 

Company. 

Heck, T. J., R. D. LeFever, D. W. Fischer, and J. LeFever. 

2002. Overview of the petroleum geology of the North 

Dakota Williston Basin. Bismarck: North Dakota 

Geological Survey. 

http://www.nd.gov/ndgs/Resources/WBPetroleum_H.

htm (accessed April 19, 2007), Web page modified 

February 7, 2007. 

Heffern, E. L., and D. A. Coates. 2004. Geologic history 

of natural coal- bed fires, Powder River Basin, USA. 

International Journal of Coal Geology 59:25–47. 

Heffern, E. L., D. A. Coates, J. Whiteman, and M. S. Ellis. 

1993. Geologic map showing distribution of clinker in the 

Tertiary Fort Union and Wasatch formations, northern 

Powder River Basin, Montana. Coal Investigations 

Map C- 142 (scale 1:175,000). Washington, D.C.: U.S. 

Geological Survey. 

Hickey, L. J. 1977. Stratigraphy and paleobotany of the 

Golden Valley Formation (early Tertiary) of western 

North Dakota. Memoir 150, text (181 p.), 55 pls. (scale 

1:250,000). Boulder, CO: Geological Society of 

America. 

Hinchman, S. 1993. Oil firms commandeer badlands. 

High Country News 25(7):1. 

Hoganson, J. W., and J. Campbell. 1997. Paleontology of 

Theodore Roosevelt National Park. NDGS Newsletter

24(1):12–23. 

Iierkley, J., G. Reetz, and D. Vana- Miller. 1998. Water 

Resources Management Plan Theodore Roosevelt 

National Park North Dakota. National Park Service. 

http://www.nature.nps.gov/water/management_plans/

thro_final_screen.pdf (accessed May 8, 2007) 

Laird, W. M. 1950. The geology of the South Unit, Theodore 

Roosevelt National Memorial Park. Bulletin 25. 

Bismarck: North Dakota Geological Survey. 

Laird, W. M. 1956. Geology of the North Unit, Theodore 

Roosevelt National Memorial Park. Bulletin 32. 

Bismarck: North Dakota Geological Survey. 
 THRO Geologic Resource Evaluation Report 31

Madole, R. F. 1995. Spatial and temporal patterns of late 

Quaternary eolian deposition, eastern Colorado, 

U.S.A. Quaternary Science Reviews 14:155–177. 

Muhs, D. R., J. B. Swinehart, D. B. Loope, J. N. 

Aleinikoff, and J. Been. 1999. 200,000 years of climate 

change recorded in eolian sediments of the High 

Plains of eastern Colorado and western Nebraska. In 

Colorado and adjacent areas, Field Guide 1, eds. D. R. 

Lageson, A. P. Lester, and B. D. Trudgill, 71–91. 

Boulder, CO: Geological Society of America. 

Murphy, E. C., J. P. Bluemle, and B. M. Kaye. 1999. 

Roadlog guide for the South & North units, Theodore 

Roosevelt National Park. Educational Series 22. 2nd 

printing. Bismarck and Medora, ND: North Dakota 

Geological Survey North Dakota Geological Survey, 

and Theodore Roosevelt Nature and History 

Association. 

National Park Service. 2002. Theodore Roosevelt National 

Park: Environmental assessment boundary expansion 

study. Englewood, CO: Engineering- Environmental 

Management, Inc. 

http://data2.itc.nps.gov/parks/thro/ppdocuments/FIN

AL%20PUBL%20EA- NOVEMBER.pdf (accessed 

April 27, 2007). 

Opdahl, D. D., W. F. Freymiler, L. P. Haugan, R. J. 

Kukowski, B. C. Baker, and J. G. Stevens. 1975. Soil 

survey of Bowman County, North Dakota. Bismarck, 

ND: U.S. Department of Agriculture Soil Conservation 

Service, North Dakota State Office. 

Ramani, R. V., and E. C. Grim. 1978. Surface mining: A 

review of practices and progress in land disturbance 

control. In Reclamation of drastically disturbed lands, 

eds. F. W. Shaller and P. Sutton, 241–270. Madison, WI: 

American Society for Agronomy. 

Santucci, V. L., and A. Koch. 2003. Paleontological 

resource monitoring strategies for the National Park 

Service. Park Science 22(1):22–25. 

Summerfield, M. A. 1991. Global geomorphology: An 

introduction to the study of landforms. New York: John 

Wiley & Sons, Inc. 

Trimble, D. E. 1993. The geologic story of the Great Plains. 

Medora, ND: Theodore Roosevelt Nature and History 

Association. 

USDA Forest Service. 2001. Final environmental impact 

statement for the northern Great Plains management 

plans revision. Chadron, NE: USDA Forest Service. 

USDA Forest Service and Bureau of Land Management. 

2003. Dakota Prairie Grasslands oil and gas leasing 

record of decision: Little Missouri and Cedar River 

National Grasslands, Slope, Billings, Golden Valley, 

Grant, Sioux and McKenzie counties, North Dakota. 

Bismarck, ND, and Billings, MT: USDA Forest Service 

and Bureau of Land Management. 

Wiebmer, J. D. 1977. Lignite and North Dakota: A 

cautious response to accelerated mining demands. 

Mining Engineering August 1977:24–35.
 NPS Geologic Resources Division 32 

Appendix A: Geologic Map Graphic 

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

Roosevelt National Park. For a poster size PDF of this map or for digital geologic map 

data, please see the included CD or visit the GRE publications webpage: 

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


The U.S. Department of the Interior is the nation's principal conservation agency, charged with the mission "to protect and provide access to 

our Nation's natural and cultural heritage and honor our trust responsibilities to Indian tribes and our commitments to island communities." 

More specifically, Interior protects America’s treasures for future generations, provides access to our nation’s natural and cultural heritage, 

offers recreation opportunities, honors its trust responsibilities to American Indians and Alaska Natives and its responsibilities to island 

communities, conducts scientific research, provides wise stewardship of energy and mineral resources, fosters sound use of land and water 

resources, and conserves and protects fish and wildlife. The work that we do affects the lives of millions of people; from the family taking a 

vacation in one of our national parks to the children studying in one of our Indian schools. 

Theodore Roosevelt National Park 

Geologic Resource Evaluation Report 

Natural Resource Report NPS/NRPC/GRD/NRR—2007/006 

NPS D-133, June 2007 

National Park Service 

Director • Mary A. Bomar 

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 • Katie KellerLynn

Editing • Trista Thornberry- Ehrlich and Melanie Ransmeier 

Digital Map Production • Stephanie O’Meara, Victor deWolfe, Robert Thompson, and Anne Poole 

Map Layout Design • Andrea Croskrey
Geologic Resources Division 

Natural Resource Program Center 

P.O. Box 25287 

Denver, CO 80225 

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

(303) 969-2090 

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National Park Service 

U.S. Department of the Interior