Badlands National Park 

Geologic Resource Evaluation Report 

Natural Resource Report NPS/NRPC/GRD/NRR—2008/036 

National Park Service 

U.S. Department of the Interior 

Natural Resource Program Center 
THIS PAGE: THIS PAGE: 

Yellow Mounds Paleosols, Badlands NP

ON THE COVER: ON THE COVER: 

View from Cedar Pass, Badlands NP

NPS Photos by: Dave Kr NPS Photos by: Dave Krueger and Jim F. Wood ueger and Jim F. Wood 
Badlands National Park 

Geologic Resource Evaluation Report 

Natural Resource Report NPS/NRPC/GRD/NRR—2008/036 

Geologic Resources Division 

Natural Resource Program Center 

P.O. Box 25287 

Denver, Colorado 80225 

June 2008 

U.S. Department of the Interior 

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

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

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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 

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

Please cite this publication as: 

Graham, J. 2008. Badlands National Park Geologic Resource Evaluation Report. Natural 

Resource Report NPS/NRPC/GRD/NRR—2008/036. National Park Service, Denver, 

Colorado. 

NPS D- 155, June 2008 
 BADL Geologic Resource Evaluation Report iii

Table of Contents 

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

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

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

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

Regional Setting .........................................................................................................................................................2

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

Cultural History...........................................................................................................................................................3

Geologic Issues............................................................................................................. 7

Mass Wasting Hazards...............................................................................................................................................7

Paleontological Resources .........................................................................................................................................7

Geohydrology Issues..................................................................................................................................................8

Geological Resource Ideas and Interpretive Needs ...................................................................................................9

Geologic Features and Processes............................................................................. 11

Badland Topography ................................................................................................................................................11

Paleontological Resources .......................................................................................................................................12

Stratigraphic Features ..............................................................................................................................................14

Structural Features...................................................................................................................................................16

Geoarcheology .........................................................................................................................................................17

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

Map Unit Properties Table........................................................................................................................................22

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

Cretaceous Period....................................................................................................................................................25

Tertiary Period..........................................................................................................................................................26

Quaternary Period ....................................................................................................................................................27

Glossary....................................................................................................................... 35

References................................................................................................................... 37

Appendix A: Geologic Map Graphic .......................................................................... 40

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

List of Figures 

Figure 1. Regional location map.....................................................................................................................................4

Figure 2. Park map of Badlands National Park ..............................................................................................................5

Figure 3. Generalized stratigraphic column for Badlands National Park ........................................................................6

Figure 4. Detail of the trails in the Cedar Pass area of the North Unit............................................................................6

Figure 5. Mass wasting potential in Badlands National Park..........................................................................................9

Figure 6. The Big Pig Dig site ......................................................................................................................................10

Figure 7. Badlands topography and paleosols .............................................................................................................18

Figure 8. The Wall........................................................................................................................................................19

Figure 9. Titanothere skeleton......................................................................................................................................20

Figure 10. Clastic dike..................................................................................................................................................20

Figure 11. Geologic time scale.....................................................................................................................................29

Figure 12. Paleogeographic map of North America, Late Devonian. ..........................................................................30

Figure 13. Paleogeographic map of North America, Late Permian. .............................................................................31

Figure 14. Paleogeographic map of North America, Late Cretaceous. ........................................................................32

Figure 15. Paleogeographic map of North America, Eocene Epoch of the Tertiary Period..........................................33

Figure 16. Paleogeographic map of North America, Pleistocene Epoch of the Quaternary Period..............................34
 BADL Geologic Resource Evaluation Report 1

Executive Summary 

This report accompanies the digital geologic map for Badlands National Park in South 

Dakota, which the Geologic Resources Division produced in collaboration with its partners. 

It contains information relevant to resource management and scientific research. 

Badlands National Park encompasses 242,755.94 acres in 

southwestern South Dakota and is home to striking 

erosional formations and the world’s richest collection 

of Oligocene- age vertebrate fossils. More than 250 

vertebrate species, including both herbivores and 

carnivores, are represented in the park. Fossil beds in the 

Eocene and Oligocene formations of the White River 

Group allow reconstruction of the evolution of these 

mammal species and their habitat. Paleontological 

resources were a major reason for establishing Badlands 

as a National Monument in 1939, for adding acreage in 

1976, and for elevating the monument to National Park 

status in 1978. 

Today’s landscape is dramatically different from the 

forests and savannas that covered the area in the 

Oligocene. Vegetation is sparse and erosion has carved 

the region into distinctive spires, pinnacles, hoodoos, 

monuments, buttes, and mesas that are known 

collectively as the White River Badlands. Badland 

topography was first recognized and described in South 

Dakota and the White River Badlands are the type 

locality for other areas that display similar intricately 

eroded topography. 

Weathering and erosion processes and abundant 

paleontological resources have given rise to two primary 

geologic issues facing resource managers at Badlands 

National Park: 

• Mass wasting, and 

• Fossil theft. 

Erosion is a natural process that is largely responsible for 

the development of badlands topography and exposure 

of paleontological resources. Mass wasting, the 

downslope transport of soil and rock material by gravity, 

is the primary geologic issue at Badlands National Park. 

Some of the highest known rates of erosion occur in the 

South Dakota badlands. Ridges and pinnacles have 

collapsed overnight as a result of a single thunderstorm. 

Swelling clay in the poorly consolidated strata creates 

instability of soil and rock and the potential for mass 

wasting in the park. Landslides and slumps may bury 

cultural and fossil sites as well as impact roads and other 

infrastructure. Landslides may also expose previously 

undiscovered paleontological sites. The potential 

rerouting of the Badlands Loop Road, the main road into 

the park, and the effect it would have on the geological 

and paleontological resources, viewshed, and historical 

integrity of Badlands National Park are of concern to 

park managers. 

Fossil theft from poachers and visitors is a continual 

issue for park management. While thousands of 

specimens have been collected legitimately over the 

years, many have also been stolen from the park. In the 

summer of 2000, Badlands National Park staff began 

documenting fossil resources in the park in order to gain 

a better understanding of the stratigraphic position, 

depositional environment, and degree of preservation of 

the fossil sites in the park. The goal of a complete 

paleontological inventory continues with each field 

season adding valuable information to the fossil database 

at the park. Easily accessible fossil sites are identified 

through the inventory, allowing the management team to 

protect these sites from poachers. 

In addition to mass wasting and fossil theft, 

geohydrology and geologic interpretation are areas that 

may warrant management attention. 

The exceptional paleontological resources and 

extraordinary badlands landscape, including the 

prominent Wall, are just two geologic features that 

welcome visitors to Badlands National Park. Between the 

Cretaceous and Tertiary strata that form the pinnacles 

and buttes of the badlands, is a zone of distorted, 

convoluted bedding that marks the occurrence of some 

unusual and unexplained Late Cretaceous event. Red 

and yellow striations that add color to the grayish- green 

badlands are Tertiary paleosols (ancient soils). Some of 

these paleosols form marker beds that identify distinct 

stratigraphic boundaries and a transition from a wet to a 

dry climate. 

The Badlands strata record approximately 75 million 

years of Earth history. Past marine, near- shore, and 

terrestrial environments are all reflected in the 

sedimentary rocks exposed in the park. The same 

weathering, mass wasting, and erosion processes that 

formed the landscapes in the past continue to create the 

distinctive badlands topography and landforms and 

expose the fossils that are visible today. 
 NPS Geologic Resources Division 2 

Introduction 

The following section briefly describes the National Park Service Geologic Resource 

Evaluation Program and the regional geologic setting of Badlands National Park. 

Purpose of the Geologic Resources 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. 

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/). 

Regional Setting 

Badlands National Park is located in southwestern South 

Dakota about 80 km (50 mi) east of the Black Hills (fig. 1) 

and is home to the world’s richest Oligocene- age (33.9-

23.03 Ma) vertebrate fossil deposit. These fossils, 

discovered in the White River Group, are a major reason 

for the parks existence. Pictures and discussions of these 

fossil beds are found in nearly every historical geology 

textbook (Kiver and Harris 1999). 

In the mid to late 19th century and early 20th century 

museums and universities sent numerous fossilcollecting expeditions to the Badlands region. These 

expeditions competed with private and amateur 

collectors for the fossil- rich terrestrial deposits (bone 

beds) of the Tertiary White River Group. In order to 

preserve the area, individuals in the South Dakota State 

Legislature petitioned the Federal Government to 

establish a national park as early as 1909. Norbeck Pass 

commemorates the efforts of Senator Peter Norbeck 

who championed the park concept that resulted in the 

authorization of Badlands National Monument in 1929 

and its establishment in 1939. The monument was 

redesignated as Badlands National Park in 1978. 

Boundary changes occurred in 1936, 1952, and 1968. In 

1976, the Badlands Wilderness Area was created. 

Badlands National Park is comprised of three units. The 

North Unit, also called the Sage Creek Unit, contains 

64,250 acres of designated wilderness. Contiguous with 

the North Unit, the South Unit, or Stronghold Unit, is 

located within the Pine Ridge Indian Reservation. The 

Palmer Unit lies to the east of the South Unit and also is 

within the Pine Ridge Indian Reservation (fig. 2). 

Throughout the park erosion has produced distinctive 

spires, pinnacles, hoodoos, monuments, buttes, and 

mesas known collectively as the White River Badlands. 

Badlands National Park contains the largest protected 

mixed grass prairie in the United States. The park also is 

the site of the reintroduction of the endangered blackfooted ferret. 

Geologic Setting 

Badlands National Park is located in the Great Plains 

Physiographic Province of southwestern South Dakota. 

Elevations range from 750 m (2,460 ft) along Sage Creek, 

an ephemeral tributary stream to the Cheyenne River, to 

1,000 m (3,280 ft) on Sheep Mountain Table. Rivers 
 BADL Geologic Resource Evaluation Report 3

draining the higher plateaus east of the Black Hills have 

dissected the region and contributed to the creation of 

badlands topography. Badlands National Park is 

bounded by the Cheyenne River drainage basin to the 

north and west, the Bad River drainage basin to the east, 

and the White River drainage basin to the south. 

Approximately 75 million years of accumulated 

sediments and intermittent periods of erosion are 

recorded in the generally flat- lying (layer- cake) strata of 

Badlands National Park (fig. 3). The oldest rocks exposed 

in the park are the Upper Cretaceous marine mudstones 

of the Pierre Shale. The Fox Hills Formation overlies the 

Pierre Shale, here recent investigations have revealed 

previously unrecognized latest Cretaceous fossils. 

The Tertiary White River Group (fig. 3) overlies the Fox 

Hills Formation and contains basal paleosols visible as 

brilliant red bands of color in the badlands formations. 

Vast quantities of sediment that eroded from the Black 

Hills and Rocky Mountain uplifts following the 

Cretaceous- Tertiary Laramide Orogeny, were carried 

eastward and southward by streams during late Eocene 

and Oligocene time forming the fossil rich Chadron and 

Brule Formations. Volcanoes in the Great Basin and 

Rocky Mountain areas provided abundant volcanic ash 

that also became part of the Brule Formation. The 3- 7 m 

(10- 23 ft) thick Rockyford Ash layer at the base of the 

Sharps Formation resulted from a catastrophic volcanic 

eruption in the Great Basin (Larson and Evanoff 1998). 

During the Oligocene deposition of the Brule Formation, 

the region that is now the White River Badlands was 

lush, wet, and much warmer than today. Many different 

kinds of animals roamed the floodplain. Fossils 

discovered in the beds of the White River Group 

represent over 50 species of herbivores and 14 species of 

carnivores (Kiver and Harris 1999). The White River 

beds have been called “the most complete succession of 

mammal fossils known anywhere in the world” 

(Wicander and Monroe 1993, p. 541). 

Streams draining the Rocky Mountains during the 

Pliocene deposited coarse- grained sediments (such as 

the Medicine Root Gravel) in the Badlands area. 

Sustained erosion of the Badlands began about 500,000 

years ago (Kiver and Harris 1999; Rachel Benton, NPS 

paleontologist, Badlands National Park, written 

communication, February, 2006). At this time, the 

Whiter River, now flowing west to east 8- 16 km (5- 10 mi) 

south of the park, eroded a scarp that through 

differential erosion has since formed “the Wall,” a 

prominent geomorphic feature of Badlands National 

Park. 

Today, the Wall acts as a boundary that separates the flat 

grassy Upper Prairie to the north from the Lower Prairie 

to the south. The Wall of Badlands National Park towers 

as much as 46 m (150 ft) above the upper grassland and 

up to 140 m (460 ft) above the lower grasslands near the 

Cedar Pass Visitor Center (fig. 4) (Weedon 1990). This 

geomorphic feature also acts as a water divide. North of 

the Wall, Sage Creek and Bad River drain the grasslands, 

northward to the Cheyenne River and northeastward to 

the Missouri River respectively. Intermittent streams 

drain the lower grasslands and flow southward to the 

White River. 

Periodically cliffs in the Wall break loose forming 

slumps. Slumps create holes, pits, and seasonal ponds in 

the disturbed strata. Faults that displace the colorful 

horizontal layers are also visible along the Wall as are 

clastic dikes. The faults are part of the Sage Creek 

anticline and fault system, called the Sage Creek Arch, 

which forms one of the more prominent geologic 

structures in the region (Stoffer 2003). The crest of the 

southeast- to- northwest- trending Sage Creek anticline 

parallels the Badlands Loop Road. 

Cultural History 

Archaeological evidence records Paleo- Indian use of the 

area as early as 11,000 years ago. The Arikara who were 

mammoth hunters were the first known tribe to inhabit 

the White River area. In the mid- 18th century, the Lakota 

Sioux, who had been displaced westward by the advance 

of Euro- American settlers, displaced the Arikara. The 

Lakota called this area “mako sica,” or “land bad.” 

The 18th century French fur traders echoed the Lakota 

sentiments when they called the area “les mauvaises 

termes a traverser,” or “bad lands to travel across.” In 

1843, fur trader, Alexander Culbertson, collected a large 

fossilized jaw fragment on one of his trips. The jaw found 

its way to Dr. Hiram A. Prout, a St. Louis physician, who 

stated in 1846 that it came from a creature he called a 

Paleotherium. In 1849, Dr. Joseph Leidy renamed Prout’s 

Paleotherium, Titanotherium prouti in a paper he 

published about an Oligocene camel. Leidy went on to 

publish a series of papers about North American fossils, 

many of which were from the White River Badlands. 

From the late 1800s and continuing today, scientists and 

researchers from institutions from all over the world 

have studied the renowned fossil resources of the White 

River Badlands. 

Homesteaders didn’t have much impact on the Badlands 

until well into the 20th century. In this harsh, semi- arid, 

wind- swept land, the standard 160- acre homestead 

proved too small to support a family and was increased 

to 640 acres. In response to homesteading, cattle 

replaced the bison and wheat fields replaced the prairies 

on the South Dakota landscape. 

During World War II the United States Air Force (USAF) 

took possession of 341,726 acres of land on the Pine 

Ridge Indian Reservation for a gunnery range. Included 

in the gunnery range were 337 acres of then Badlands 

National Monument. Firing took place primarily within 

the present- day Stronghold District of the park. In 1968 

the USAF returned the land to the Pine Ridge Indian 

Reservation and in 1970 a Memorandum of 

Understanding established how the NPS manages this 

area today.
 NPS Geologic Resources Division 4 

Figure 1. Regional location map showing the location of Badlands National Park in relation to the Black Hills, Mount Rushmore 

National Memorial, Jewel Cave National Monument, and Wind Cave National Park. 
 BADL Geologic Resource Evaluation Report 5

Figure 2. Park map of Badlands National Park showing the North Unit (Sage Creek Unit), the South Unit (Stronghold Unit), and the 

Palmer Creek Unit. 
 NPS Geologic Resources Division 6 

Period Epoch Thickness 

in meters Group Formation Member or Facies 

Quaternary 

Undivided - stream 

terraces, landslides, & 

floodplain deposits 

Miocene- Pliocene(?) 

(1.81- 23.03 Ma) Medicine Root Gravels 

~30 Sharps 

Formation 

2- 4 

Arikaree 

Group Rockyford Ash 

Poleslide Member 

Oligocene 

(23.03- 33.9 Ma) 

100 

Brule 

Formation Scenic Member 

10- 15 Peanut Peak Member 

Chadron Fm Crazy Johnson Member 

Ahearn Member 

Interior paleosol 

Tertiary 

Eocene 

(33.9- 55.8 Ma) 

0- 4 

Chamberlain 

Pass Fm 

White 

River 

Group 

Yellow Mounds paleosol 0- 16 Unnamed marine facies 

0- 3 (Disturbed Zone) 

0- 8 Enning facies 

Timber Lake Member 

6- 26 

Fox Hills 

Formation 

Trail City Member 

10- 36 Elk Butte facies 

Mobridge facies 

Upper Cretaceous 

(Maastrichtian Age) 

(65.5- 70.6 Ma) 

25- 30 Virgin Creek facies 

Verendrye facies 

Cretaceous 

Upper Cretaceous 

(Campanian Age) 

(70.6- 83.5 Ma) 

10 

Pierre Shale 

Degrey facies 

Figure 3. Generalized stratigraphic column for Badlands National Park. Members of the Fox Hills Formation are recognized at its type 

section in the northern Missouri River Valley region but are not differentiated in Badlands National Park. The Fox Hills Formation only 

occurs sporadically along the northern margins of Badlands National Park. Where the Fox Hills Formation is absent, the Yellow 

Mounds paleosol developed on and in the Pierre Shale. Age dates are from the International Commission on Stratigraphy (2004) 

available on at http://www.stratigraphy.org (access July, 2006). The stratigraphic column is modified from Stoffer (2003). 

Figure 4. Detail of the trails in the Cedar Pass area of the North Unit. 
 BADL Geologic Resource Evaluation Report 7

Geologic Issues 

A Geologic Resource Evaluation scoping session was held for Badlands National Park 

on June 12, 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 geologic issues section addresses geologic issues as 

they affect the ecosystem, their importance to park 

management, and the extent to which they are 

anthropogenically influenced. The following issues are 

listed in order of priority as discussed during the scoping 

workshop at the park. 

Mass Wasting Hazards 

Some of the highest known rates of erosion occur in the 

badlands with some surfaces reduced by 2.54 cm (1 in) 

every year (Kiver and Harris 1999; Stoffer 2003). Ridges 

and pinnacles have collapsed overnight as a result of a 

single thunderstorm. Because most of the White River 

strata are poorly consolidated and thus, easily eroded, 

mass wasting processes are the most important geologic 

issue facing the management of Badlands National Park 

(fig. 5). Soil and rock stability, structural stability, and the 

potential for landsliding need to be evaluated prior to 

any development in the park. An inventory and study of 

slope stability would help identify potentially hazardous 

areas. 

Landslides have been mapped in the Cedar Pass area, at 

Norbeck Pass, Sage Creek, and along the Cliff Shelf Trail 

(fig. 4). The lack of abundant vegetation and steep slopes 

allow short, intense rainfall events to produce flash 

floods. Formations associated with the largest number of 

landslides are the Brule Formation and the Pierre Shale. 

The Badlands Loop Road (route 240–the main road into 

Badlands National Park) is built on several active 

landslides within the Brule Formation. The road requires 

constant repair and is sometimes a hazard to the public. 

Major landsliding in the Pierre Shale also impacts the 

Sage Creek Rim Road. 

Landslide deposits in Badlands National Park may be 

fault related. Higher than average rainfall in 1995 caused 

the Cedar Pass Slide to move over 0.9 m (3 ft) during a 

period of 3 months along a trend parallel to the Pass 

Creek fault. Landslides have been mapped extending 610 

m (2,000 ft) from scarps along vertical joints that trend 

N. 80o

 W. within the Cedar Pass area. At Norbeck Pass, 

landslide deposits are mapped along normal faults that 

trend northwest (Ashworth et al. 1996). 

The Cliff Shelf Trail crosses a large slump block that has 

detached from the cliff behind it and slipped downward, 

rotating backward. During wetter years, the slump 

continues to slip and disrupts the Loop Road (Kiver and 

Harris 1999). Water trapped on the back section of the 

slump block promotes a luxurious growth of vegetation. 

Mass wasting contributes sediment directly to some 

stream channels. An active slump along Sage Creek 

constantly adds new sedimentary material directly to the 

stream (Stoffer 2003). 

Swelling clays derived from volcanic ash swell when wet 

and contract when dry, forming a “popcorn- like 

surface” that makes root establishment difficult and 

further encourages high rates of erosion. The Tertiary 

Chadron Formation and the Cretaceous Pierre Shale 

have high swelling clay contents. Erosion in these areas 

that lack significant vegetation has produced a karst- like 

terrain (pseudokarst) in parts of Badlands National Park. 

Pseudokarst terrains are characterized by closed 

depressions, sinking streams, and caves produced by 

processes other than the dissolution of rock. 

In Badlands National Park, landslides and slumps may 

bury cultural and paleontological resource sites while 

potentially exposing new fossil sites. More studies and 

research on pseudokarst, rates of erosion, and how 

fossils are exposed and buried by landslides are needed 

to define the links between landslide areas and cultural 

and paleontological resources. 

Specific concern was raised during the scoping session 

regarding potential rerouting of the Badlands Loop 

Road. The effect any change would have on the geologic 

and paleontologic resources, the viewshed of the park, 

and the integrity of the Wall are of great importance to 

park staff and visitors. Badlands National Park continues 

to work with Federal Highways personnel and private 

contractors on these issues. 

Paleontological Resources 

The world class fossil beds of the White River Group in 

Badlands National Park allow detailed study and 

reconstruction of the evolution of sheep- like and piglike mammals as well as the horse and rhinoceros. The 

fossilized remains of more than 250 vertebrate species 

are found in Badlands National Park. 

The park paleontologist coordinates research with 

universities, colleges, and museums. Research staff 

prepare fossils, conduct field surveys, and document the 

fossil condition and history in the Badlands strata. 

Thousands of fossil specimens have been legally 

collected from Badlands National Park, however fossil 
 NPS Geologic Resources Division 8 

poaching is a major issue. For example, the South Unit 

contains many historic collecting and research areas, 

some of which date back to scientific surveys of the late 

1800s. On October 26, 1999, a park ranger discovered 

illegal diggings at the remote Titanothere Bone Bed site 

in the South Unit. Follow- up surveys documented more 

than 18 poaching sites. The poachers were never caught, 

and rangers now patrol the site on a regular basis. 

The Big Pig Dig site, a complex assemblage of beautifully 

preserved mammal bones that serves both research and 

education, is located adjacent to a moderately traveled 

gravel road providing easy access for researchers as well 

as visitors (fig. 6). Ease of access to the Pig Dig site also 

poses serious vandalism threats. To deter vandalism and 

poaching, the park has installed a boundary fence around 

the site, two shelters, and a locking storage shed (Benton 

2003). Rangers patrol the area and during the field season 

paleontology interns are onsite seven days a week. 

Fossils illegally collected by park visitors are probably 

relatively close to roads and trails, whereas amateur and 

commercial collectors usually collect larger numbers of 

fossils from more remote sites. The number of cases of 

illegal fossil collection investigated has increased from 

one case in 1998 to 32 in 2000, 72 in 2001, 37 in 2006, and 

41 in 2007(National Park Service 2005; Rachel Benton, 

NPS paleontologist, Badlands National Park, written 

communication, August 21, 2007 and March 24, 2008). 

In 2000, a pilot project funded by the National Park 

Service Natural Resources Preservation Program 

(NRPP) allowed Badlands National Park to begin 

documenting the fossils in the lowest horizons of the 

fossiliferous Scenic Member of the Brule Formation 

(Benton et al. 2001). Easy access to the lowermost portion 

of the Scenic Member exposes it to greater threat of 

poaching and was one reason that the lowermost portion 

of the Scenic Member was chosen for survey. The NRPP 

bone- bed mapping project included the following: 

• A paleontological site inventory including the 

identification and taphonomic analysis of each 

paleontological specimen found, 

• A baseline data set including stratigraphic position, 

depositional environment, and degree of preservation, 

• A detailed stratigraphic analysis of the Brule 

Formation, and, 

• The location of easily accessible fossil resources so that 

the management team at Badlands can protect fossil 

sites within the park. 

Through the NRPP, Badlands staff also is working in 

partnership with cooperating museums and universities 

to further document the paleontology, stratigraphy, and 

sedimentology of the Poleslide Member of the Brule 

Formation. 

After the first summer of fieldwork in 2000, the team had 

documented and recorded 351 new paleontological sites 

in the park’s Geographic Information System (GIS) 

(Benton et al. 2001). While hundreds of specimens occur 

in bone horizons at many of these sites, only 231 

specimens were collected during the initial fieldwork. 

Criteria used to justify collection included threats from 

erosion or poaching and the overall scientific value of the 

fossil. 

The NRPP bone- bed project marks the first time in the 

history of Badlands National Park that the extent and 

location of fossil resources have been documented. 

Fieldwork continues in the park and each locality is 

recorded in the park’s GIS paleontological database 

using GPS field data. A report documenting the 

paleontological surveys completed from 2000 to 2002 is 

on file at Badlands National Park, and a report 

documenting the second set of paleontological surveys 

completed, from 2003 to 2005, will be completed in 2008 

(Benton et al. 2006; Benton et al. in progress; Rachel 

Benton, NPS paleontologist, Badlands National Park, 

written communication, August 21, 2007). 

After six years of surveys, the park continues work 

toward completing a paleontological inventory. Once 

complete, the baseline mapping and fossil survey will 

enable Badlands staff to more efficiently monitor sites 

that are threatened now or that may become threatened 

in the future. 

Construction activities related to the management 

alternatives proposed in the General Management Plan 

(GMP) for Badlands National Park may impact 

paleontological resources (National Park Service 2005). 

In the North Unit, ground disturbance from 

construction of facilities in the park headquarters area, 

redesigning the Sage Creek Campground, a new 

Pinnacles visitor contact station, and activities associated 

with changing the Loop Road could potentially affect 

fossils. In the South Unit, construction of the Lakota 

Heritage and Education Center, improvement of the 

Sheep Mountain Table road, and bombing range cleanup 

efforts may adversely impact paleontological resources. 

However, in both North and South Units, mitigation 

measures, including surveys and monitoring by 

paleontologists, should help minimize the extent of 

negative impacts (National Park Service 2005). In 

addition, the recommended management alternative 

presented in the GMP would increase the number visitor 

contact stations and outdoor classrooms thus, increasing 

visitor awareness of the significance of fossils in the park. 

Further, the plan calls for increasing the frequency of 

ranger patrols and expand the park boundary along SD 

44. Boundary expansion would improve access for 

rangers, researchers, and resource managers into the 

Badlands Wilderness Area and increase the protection of 

fossils in the area. 

Geohydrology Issues 

With increased visitation, water supply and water quality 

continue to be important issues. Scoping workshop 

participants expressed concerns about water due to 

extensive herbicide use that has contaminated both 

surface water and groundwater. The effects of 
 BADL Geologic Resource Evaluation Report 9

campground development on springs, water use at Sage 

Creek Campground, as well as potential impacts from 

any future development are potential research areas that 

could inform park decision making. 

In 1998, the Water Resources Division (WRD) of the 

National Park Service analyzed the surface water quality 

in Badlands National Park (National Park Service 1998). 

Both pH and copper content exceeded Environmental 

Protection Agency (EPA) screening criteria for 

freshwater aquatic life, and sulfate, nitrite, and lead were 

above the EPA criteria for drinking water. 

Concentrations of fecal bacteria and turbidity exceeded 

WRD screening limits for freshwater bathing and aquatic 

life, respectively. Details of the surface- water quality 

inventory and analysis for Badlands National park are 

available in Techinical Report NPS/NRWRD/NRTR98/161 (http://nrdata.nps.gov/BADL/nrdata/water/ 

baseline_wq/docs/BADLWQAA.pdf, accessed August 25, 

2007). 

Management expressed a need for maps showing natural 

and man- made ponds. Structural studies of joints and 

fractures in the rocks would help define the erosional 

and depositional processes affecting the park’s 

hydrology. 

Geological Resource Ideas and Interpretive Needs 

The following needs were identified at the GRE scoping 

meeting: 

• Publish geologic information for visitors, including 

brochures or pamphlets for self- guided tours, 

• Reprint U.S. Geological Survey geologic map I- 934, 

• Provide geologic information to students and faculty 

of geological field camps when they visit the park, 

• Develop interpretive materials for the Pig Dig site, 

• Research erosional vs. depositional origins of the 

clastic dikes in Badlands National Park, and 

• Develop a list of research needs for interested 

researchers.

Figure 5. Mass wasting potential is high on the unvegetated slopes and relatively unconsolidated strata that form the Wall in Badlands 

National Park. Note that the more resistant layers are undercut by erosion and will eventually fail. 
 NPS Geologic Resources Division 10 

Figure 6. The Big Pig Dig site in Badlands National Park is a significant visitor education and research site. Visitors learn the 

importance of protecting fossil sites and promoting paleontological research. Park staff and geology students from the South Dakota 

School of Mines and Technology and other Universities around the United States excavate the site, document the fossils, and interpret 

the site for visitors. In the background is a cast of an Archaeotherium skeleton, the pig-like mammal for which the site was named. 
 BADL Geologic Resource Evaluation Report 11

Geologic Features and Processes 

This section describes the most prominent and distinctive geologic features and processes 

in Badlands National Park. 

Badland Topography 

Weathering, mass wasting, and erosion are the physical 

processes that shape the badlands landscape (fig. 7). 

Once weathered from bedrock, mass wasting moves the 

material down an unstable slope and erosion physically 

removes the sediment to other locations by wind and 

water. Visitors are amazed by the unusual eroded 

topography of Badlands National Park. Sparse vegetation 

and a harsh climate contribute to differential erosion in 

the park, a process that has exposed fossil sites and 

stratigraphy allowing visitiors and researchers a glimpse 

into earth history. 

Geomorphic processes at work in Badlands National 

Park are influenced by the regional climate where 

presently the average annual rainfall is approximately 43 

cm (17 in) with about 77% of it occurring in late spring 

and summer (April to September) (Stoffer 2003). Rainfall 

usually occurs as short- duration thunderstorms. 

Average monthly temperatures range from –5.6o

C (22o F) 

in January to 22oC (72o F) in August with daytime 

temperatures typically reaching approximately 35o

C 

(95oF) in the afternoon. The combination of high 

summer temperatures and short rain events, along with 

dry cold winters, make growing conditions difficult for 

most plants. Lack of stabilizing vegetation promotes the 

physical processes that impact the Badlands landscape. 

The landforms are controlled by the characteristics of 

the rocks themselves. The Chadron Formation forms 

rounded, haystacklike features because it contains 

mostly clay- rich sediment. The Chadron also has a 

generally high precipitation infiltration rate due to 

desiccation cracks. This results in little surface runoff 

and reduced slope wash deposition (Schumm 1956; 

Kuehn 2002). The more rugged peaks and canyons in 

Badlands National Park are found in the Brule and 

Sharps Formations because their silty, ash- rich sediment 

is more resistant to erosion than the clay- rich Chadron 

strata. Because the Brule Formation is harder and less 

permeable than the Chadron Formation, slopes on the 

Brule Formation are influenced primarily by surface 

runoff, whereas sediment transport on Chadron 

Formation slopes is dominated by soil creep. 

The Wall 

The drainage networks of the White River (south of the 

park), the South Fork of the Cheyenne River (northwest 

of the park), and the Bad River (north of the park) 

deposited sediment, including the Medicine Root 

Gravel, in the Badlands National Park region. The White 

River cut a narrow valley, and about 500,000 years ago, 

erosion began to carve the serrated badlands 

topography. Closely spaced tributaries flowing 

southward down the steep north valley wall caused the 

valley side to erode and migrate northward as a line of 

cliffs that now stretches about 97 km (60 mi) from the 

town of Kadoka west towards Scenic. This long, narrow 

spine of buttes is known as the “Badlands Wall,” or 

“Wall.” In another 500,000 years, the badlands will have 

migrated north, destroying the Upper Prairie, which is 

the drainage divide between the White River and the 

Cheyenne River (Kiver and Harris 1999). 

The Wall separates the upper grasslands on the north 

from the lower grasslands on the south in Badlands 

National Park (fig. 8). The Wall towers as much as 46 m 

(150 ft) above the upper grasslands and as much as 137 m 

(450 ft) above the lower grassland area near the Cedar 

Pass Visitor Center (Weedon 1990). Separating the flat 

grassy Upper Prairie from the Lower Prairie, the Wall 

also acts as a water divide. Intermittent streams in the 

Lower Prairie flow southward into the White River. The 

slower, more sluggish streams that characterize the 

Upper Prairie flow northward to the Cheyenne River and 

to the Bad River. 

Other Badland Features 

Weakly consolidated, easily eroded fine- grained rock, 

steep slopes, sparse vegetation, and a semiarid climate 

combine to produce the stark terrain and classic 

erosional forms known as badland topography (fig. 8). 

Castles are large star- or block- shaped features that are 

the remnants of Tertiary and Cretaceous units. 

Monuments, or pinnacles, are isolated remnants of 

sedimentary rock. Both are prevalent throughout the 

region south of the High Pinnacles Overlook in the 

North Unit. 

Low mesas are scattered in the valley bottoms between 

the higher castles, walls, and monuments in the badlands. 

Sod tables are isolated erosional remnants of the once 

higher plains. Sod has formed a protective cover for the 

underlying, softer soil materials. The grass- covered 

surfaces are remnants of an earlier floodplain and record 

a wetter period when vegetation became established 

throughout the badlands. Sod tables can be seen in the 

“Grassy Tables” area and viewed from the High 

Pinnacles Overlook (Stoffer 2003). 

Hoodoos and caprocks are similar features. Harder 

rocks, such as sandstone, resist erosion and shelter 

softer, underlying claystone units. The harder sandstone 

is called a “caprock.” If the claystone erodes, leaving the 

caprock resting on a pedestal of softer material, the 

feature is called a “hoodoo.” They are also called 

“toadstool rocks” because of their form. Hoodoos, 
 NPS Geologic Resources Division 12 

which are smaller than castles or monuments, are 

numerous in the Badlands area. 

Yardangs were named for landscape features in the 

badlands of South Dakota (Baker 1951). These irregular, 

sharp- crested, undercut ridges are carved by wind 

erosion into soft but coherent deposits such as clayey 

sand. They are oriented in the direction of the dominant 

wind and may be as much as 6 m (20 ft) high and 40 m 

(130 ft) wide. 

Rapid erosion in channels has also formed natural arches 

and bridges in Badlands National Park. These fragile 

features, however, are short- lived. 

Flash floods remove sediment and often produce 

rounded, baseball- size clay masses called armored 

mudballs because their outer surfaces are coated with 

sand, pebbles and rock fragments. 

Globular shaped geodes are discrete nodules that 

weather out of all the White River Badlands formations, 

but they are most numerous in the nodular zones of the 

Brule Formation (Harris et al. 1997; Weedon 1990). The 

outer layer of the geodes is composed of dense 

chalcedony. Crystals, commonly calcite or quartz, 

project into the hollow center of the geode. 

Paleontological Resources 

Badlands National Park contains some of the most 

species- diverse Oligocene fossil beds in the world, 

contributing greatly to the science of vertebrate 

paleontology. All sizes of animals, from rodents to the 

elephant- size Titanotheres, lived on the floodplains that 

covered the Badlands region during the Oligocene. 

Golden moles, hedgehogs, and shrews ate Oligocene 

insects. Recent research on the Oligocene camelid, 

Poebrotherium wilsoni, has shed light on the dietary 

habits of these camelids as well as Oligocene climate 

(Wall and Hauptman 2001). 

Fossils from the Oligocene strata of the White River 

Badlands have nearly twice as many mammalian families 

than are known today for all of North America (Weedon 

1990). More than 50 species of herbivores and 14 species 

of carnivores have been discovered in the Eocene and 

Oligocene White River Group, primarily in the 

Oligocene Brule Formation (fig. 3) (Kiver and Harris 

1999). 

Brule Formation 

The Brule Formation was originally described as the 

“turtle and oreodont beds” by the Meek and Hayden 

Survey in the late 1850s (Stoffer 2003). Oreodonts were 

primitive ruminants only found in North America. They 

were about the size of sheep and roamed the plains in 

large herds (Harris et al. 1997). 

Remains of land turtles and oreodonts (especially 

Merycoidodon) are common in some layers of the lower 

Scenic Member of the Brule Formation. The lower 

Scenic Member includes the rocks between the 

underlying Chadron Member and the top of the first 

marker bed, called marker unit 1. This marker bed is a 

widespread greenish gray noncalcareous mudstone bed 

that is characterized by abundant mudstone and 

claystone rip- up clasts, root traces, and scattered streaks 

of white limestone (Benton et al. 2001). Channel sand 

deposits in the Scenic Member were originally called the 

“Metamynodon beds” for bone beds containing an 

aquatic variety of rhinoceros. Deposited in paleovalleys 

cut into the Chadron Formation, the lower Scenic 

Member ranges from 8.7- 25 m (29- 82 ft) in thickness. 

Oreodont fossils are abundant in both the Scenic 

Member and the Poleslide Member of the Brule 

Formation (Benton et al. 2001; Stoffer 2003; Benton et al. 

2004; Mintz et al. 2005).The overlying Poleslide Member 

of the Brule Formation preserves fossils of a horned 

sheep- sized herbivore, Proteroceras, and also contains 

oreodonts (genus Leptauchenia) (Stoffer 2003). 

In 1993, two visitors from Iowa discovered a large 

backbone near the Conata Picnic Area. This discovery 

became the Conata Picnic Area Paleontological Site and 

is one of the more significant paleontological finds in 

recent years at Badlands National Park (fig. 6) (Benton 

2003). The site, discussed above, is better known as the 

Big Pig Dig, or, simply, the Pig Dig, named for 

Archaeotherium, a large pig- like mammal uncovered 

there. As many as 100 elements per m2

 are preserved at 

the site, which is biased towards animals of a large body 

size (Bjork 1994; Ashworth et al. 1996; Benton 2003). 

Intermixed bones of such animals as Archaeotherium, 

Subhyracodon (a hornless rhinoceros), Mesohippus 

(Oligocene horse), and Leptomeryx (foot- high deer- like 

creature) are preserved in a light, olive- gray mudstone 

layer in the Scenic Member of the Brule Formation. This 

mudstone layer can reach a thickness of 89 cm (35 in) 

(Ashworth et al 1996; Benton et al. 2001). 

The fossil accumulation at the Pig Dig is unique in the 

badlands because of the density of bone material and the 

way in which the fossils were preserved. Vertebrate 

fossils are most commonly preserved in the badlands 

either as attritional bone accumulations on ancient land 

surfaces or bones that have been incorporated into 

channel sandstone deposits. In contrast, the randomly 

oriented, semi- articulated to disarticulated bones at the 

Pig Dig have been preserved in an Oligocene watering 

hole. The site gives visitors an opportunity to watch 

paleontologists conducting the arduous, timeconsuming task of carefully excavating and preparing 

fragile fossils for a move to the park’s museum collection. 

During a recent NPS survey more than 1000 fossil sites 

were documented in the Poleslide Member (Benton et al. 

2004). Fossils include a horned sheep- size herbivore, 

Protoceras, and oreodonts (Stoffer 2003). The 

association of vertebrate accumulations with paleosols 

supports the environmental interpretation of long- term 

stable land surfaces and periods of rapid eolian 

deposition when the bones were quickly buried. Stable 

land surfaces are marked by dense zones of fossil roots, 
 BADL Geologic Resource Evaluation Report 13

dung balls, and burrows, while times of eolian 

aggradation are marked by massive volcaniclastic 

siltstones with sparse paleosol features (Benton et al. 

2004; Mintz et al. 2005). 

Several fossil sites, also within the lower Scenic Member, 

have been documented within the Badlands Wilderness 

Area. One of the more recent discoveries is the Brian 

Maebius bone bed in Tyree Basin, the first valley west of 

the Sage Creek Basin in the North Unit (Benton et al. 

2001). The site contains a greater diversity of fauna than 

the Pig Dig site and also contains fossilized wood, pollen, 

and coprolites. 

Chadron Formation 

The Chadron Formation (uppermost Eocene), which 

underlies the Brule Formation, is known for 

Titanotheres (fig. 9). The Titanothere, Brontothere

(“thunder- beast”), discovered in 1846, was the first 

Badlands fossil to be described. Titanotheres belong to 

the genus, Brontotherium , an extinct family of

perissodactyls, or odd- toed ungulates, and are 

considered to be the largest and most impressive of the 

early mammals preserved at Badlands National Park. 

About the size of an Indian elephant, Titanotheres 

looked similar to the modern rhinoceros but were 

actually more closely related to modern horses. 

Titaontheres stood about 4 m (12 ft) high and had huge 

blunt paired horns on their snouts (Harris et al. 1997; 

Kiver and Harris 1999). These herbivores attained their 

peak in the Oligocene. The Titanothere Bone Bed is 

located in the South Unit in strata that represent an 

Oligocene channel system that originally flowed from the 

Black Hills. 

Fox Hills Formation 

Whereas Cenozoic fossils preserve terrestrial land 

animals, Mesozoic fossils from Badlands National Park 

are mostly marine organisms that represent the last 

vestige of a sea that inundated the Western Interior of 

North America. The fossils are found in sedimentary 

rocks of Late Cretaceous age that are exposed along the 

lower stream drainages in Badlands. These marine rocks 

have an impact on the modern environment of the park. 

They weather relatively slowly compared with the 

overlying Tertiary strata, yet produce soils that are both 

rich in nutrients and hold moisture. Consequently, plants 

well adapted to the high western prairie grow well in 

areas underlain by Cretaceous bedrock. 

Shelled mollusks (mostly clams and ammonites), 

arthropods, and rare bones, teeth, and scales of fish and 

swimming reptiles are preserved in Cretaceous marine 

beds. Both the Cretaceous Pierre Shale and Fox Hills 

Formation are subdivided into more discrete intervals by 

using species of ammonites as markers (Stoffer 2003). 

At its type locality (the location where a formation is first 

described and named) in the northern Missouri River 

Valley region of South Dakota, the Fox Hills Formation 

has been subdivided into four members, the lowest two 

being fossiliferous. The Fox Hills Formation in Badlands 

National Park is unlike the exposures in the type area. 

Rather than divided into four members, the formation is 

undifferentiated in the park (Stoffer 2003). Thin ledgeforming sandstone beds of the Fox Hills Formation cap 

hilltops throughout the southern Sage Creek Wilderness 

area (especially along the South and Middle Forks of 

Sage Creek). The coiled ammonite, Jeletzkeytes 

nebrascensis, has been recovered from a red concretion 

layer in the Fox Hills Formation (Chamberlain, Jr. et al. 

2001; Stoffer 2003).Above the zone of concretions, an 

interval of green- and red- colored fossiliferous marl (a 

clay- rich limestone) yields ammonites, belemnites 

(cigar- shaped cephalopods), fish remains, plant material, 

tiny clams, oyster fragments, and other material. 

Belemnites, especially Belemnitella bulbosa, are perhaps 

the most common fossils in this interval. 

A significant change in fauna is associated with the 

Disturbed Zone (DZ), a regional zone of intense softsediment deformation as much as 5 m (16 ft) thick within 

the Fox Hills Formation (fig. 3). Two classes of mollusks 

- bivalves (numerous) and cephalopods (rare) - are the 

most abundant invertebrate fossils preserved in the DZ 

(Chamberlain, Jr. et al. 2001). While the bivalve fauna is 

abundant, it is not diverse. Only nuculid pelecypods 

occur in significant numbers, and only one species of 

nuculid has been recovered: Nucula cancellata

(Chamberlain, Jr. et al. 2001). A poorly preserved 

specimen of what probably is the inoceramid (clam), 

Spyridoceramus (=Tenuipteria) tegulatus, also has been 

discovered from the DZ. 

Two groups of cephalopods have been found in the 

disturbed zone fauna: scaphitid ammonites and 

belemnites. Significantly, baculitid ammonites, which are 

ammonoids with uncoiled shells rather than the normal 

(planispiral) form of coiling, are not present. The lack of 

baculitid ammonites supports the hypothesis that 

straight- shelled ammonoids dropped out of the fossil 

record well before the end of the Cretaceous. 

Scaphitid ammonites also have an unusual form of 

coiling. The shell of these ammonoids grows first in a 

tight coil, then straight, and finally curves back upon the 

initial coil. Scaphitids are rare and occur as isolated 

fragments at Badlands. Complete adult specimens are 

exceedingly rare, thus making identification difficult. 

The only two species that have been identified are 

Discoscaphites gulosus and Jeletzkytes nebrascensis. 

Belemnite specimens have been recovered from beds 

below the DZ in the Wilderness Access Trailhead area. 

No belemnites have been found higher than about 1 m (3 

ft) below the base of the DZ. The specimens appear to be 

Belmnitella americana, common in the Western Interior 

Seaway (Chamberlain, Jr. et al. 2001). 

Although not common, vertebrate remains have been 

discovered in the Fox Hills Formation in the Badlands 

area. Osteichthean (bony fish) scales have been found 

above, below, and within the DZ at Creighton, about 50 

km (30 mi) north of the park, and below the DZ at 
 NPS Geologic Resources Division 14 

Wilderness Access Trailhead. Chondrichthian (also 

spelled “chondrichthyan”) remains and lamniform shark 

teeth also are present at Creighton and Wilderness 

Access Trailhead. Chondrichthians are a class of 

vertebrates that includes fish with skeletons of cartilage 

rather than bone. Sharks, for example, are 

chondrichthians. Chondrichthian remains have been 

recovered from the Timber Lake Member of the Fox 

Hills Formation and mark the youngest transitional 

marine chondrichthian assemblages yet recovered from 

Cretaceous rocks of the Western Interior (Becker et al. 

2004). 

The 15 surviving species of the order Lamniformes, 

which includes the great white and mako sharks, are 

mere remnants of a much greater lamniform lineage that 

has mostly become extinct. Lamniform sharks first 

appeared in the fossil record during the early Cretaceous 

period about 120 million years ago. Lamniform sharks are 

classified within the infraclass Neoselachii (“new 

sharks”). Neoselachians are the last common ancestor of 

living sharks. By the mid- Cretaceous, about 100 million 

years ago, most modern groups of sharks had appeared. 

A partial skeleton of what might be a small, neoselachian 

shark was found at Sage Creek Basin (Chamberlain, Jr. et 

al. 2001). 

Above the DZ` an unnamed marine unit of the Fox Hills 

Formation contains an abundance of marine trace fossils 

but very scarce body fossils (Stoffer 2003). Trace fossils 

(or ichnofossils) are tracks, trails, burrows, borings, fecal 

pellets and other traces made by organisms. Although 

difficult to identify, trace fossils can yield valuable 

information regarding paleoecology and environmental 

reconstruction. They are potential indicators of 

bathymetry, currents, food supplies, oxygen supply, rate 

of deposition, depositional history, substrate stability, 

and salinity. Ichnofossils have been arranged into nine 

recurring depositional environments, called ichnofacies, 

each named for a representative ichnogenus (Pemberton 

et al. 1992). Fish bone fragments, teeth of a barracudalike fish, and plant material in the unit above the DZ 

occur along with trace fossils that represent the Skolithos

and Cruziana ichnofacies. Both Skolithos and Cruziana

are genus (ichnogenus) names for trace fossil burrows. 

Skolithos ichnofacies are indicative of relatively high 

levels of wave or current energy developed in slightly 

muddy to clean, well- sorted, loose or shifting, sandy 

substrates. Cruziana ichnofacies are characteristic of 

subtidal, poorly- sorted and unconsolidated substrates in 

deeper, quieter marine waters (MacEachern and 

Pemberton 1992; Pemberton et al. 1992). Both varieties of 

ichnofacies occur within the intertidal or shallow 

subtidal zone. Trace fossils common to both facies 

include Diplacraterion (U- shaped burrows), 

Ophiomorphia (thick branching burrows with a knobby 

texture), Thalassinoides (burrows with Y- or T- shaped 

branches), and Cruziana (crawling traces with 

“herringbone,” or chevron- like, tracks) (Stoffer 2003). 

Pierre Shale 

The upper portion of the Pierre Shale is exposed in 

Badlands National Park along Sage Creek and Sage 

Creek valley, including the lower drainage basins of East 

Fork and Middle Fork and most of South Fork, in the 

North Unit and along Cedar Creek in the South Unit. 

The giant clam, Inoceramus sagensis, occurs in large gray 

concretions and was named by the Meek and Hayden 

Survey of the late 1850’s after Sage Creek (Stoffer 2003). 

Distinctive ammonite species found in the Pierre Shale 

either within the park or the adjacent area include: 

Baculites compressus, Baculites cuneatus, Baculites 

reesidei, Baculites corrugatus, Baculites grandis, Baculites 

baculus, Baculites clinolobatus, Hoploscaphites melloi, and 

Hoploscaphites birkelundi (Stoffer 2003). While Baculites 

species are straight shelled ammonites, Hoploscaphites

species are coiled ammonites. 

Stratigraphic Features 

Disturbed Zone of Soft Sediment Deformation: The 

Disturbed Zone (DZ) at Badlands National Park is part 

of a regional zone of intense soft sediment deformation 

that is preserved within the southernmost deposits of the 

Fox Hills Formation in and around Badlands NP (Stoffer 

2003; Chamberlain, Jr. et al. 2001; Terry, Jr. et al. 2004). 

Previously hypothesized to be the result of the Chicxulub 

impact that marks the Cretaceous- Tertiary boundary, 

the DZ has been dated using dinoflagellate 

biostratigraphic data as late middle to early late 

Maastrichtian, which is equivalent to the Timber Lake 

Member of the Fox Hills Formation (Chamberlain, Jr. et 

al. 2001; Terry, Jr. et al. 2001; Stoffer 2003; Palamarczuk et 

al. 2003; Terry, Jr. et al. 2004). 

The Badlands DZ is the only zone of distorted, 

convoluted bedding anywhere in the Upper Cretaceous 

beds of southwestern South Dakota and seems to mark 

the occurrence of some unusual Late Cretaceous event 

(Chamberlain, Jr. et al. 2001; Stoffer et al. 2001; Terry, Jr. 

et al. 2004). The DZ has been documented over 300 km2

(116 mi2

) in the badlands area of South Dakota and ranges 

in thickness between about 0.5 m (1.6 ft) to as much as 5 

m (16 ft) where exposed (Chamberlain, Jr. et al. 2001; 

Stoffer 2003; Terry, Jr. et al. 2004). 

In the Badlands area, the DZ is exposed at the following 

locations: headwaters region of Conata Creek; 5 km (3 

mi) directly west of the Pinnacles Ranger Station and 

south of the Sage Rim Road near the Grassy Tables 

Overlook; at the Wilderness Access Trailhead; at stream 

level in the headwaters region of Dry Creek in the Sage 

Creek Wilderness Area near the park’s southern 

boundary; and about 1.6 km (1 mi) north of the park 

boundary in the Buffalo Gap National Grasslands. 

Physical characteristics of the DZ and adjacent strata 

include the following (Stoffer 2003): 

• Dinoflagellates that record a late middle to early late 

Maastrichtian age, 

• A diverse Late Cretaceous marine fauna below the DZ 

but not above the DZ, 
 BADL Geologic Resource Evaluation Report 15

• Mappable exposures throughout the northern portion 

of Badlands NP across a region at least 25 km (16 mi) 

wide and extending north of the park at least 30 km (19 

mi), 

• As much as 16 m (52 ft) of marine beds above the DZ 

contain abundant trace fossils but have not yielded 

Cretaceous fauna – identified fossils and traces in this 

upper interval all have modern descendents (such as 

barracuda, sharks, oysters, sand fleas, and others), 

• Oriented roll structures in the DZ with sediment layers 

rolled up like a carpet while they were soft and pliable 

– these roll structures have an east- to- west 

orientation in outcrop indicating that sediment 

movement was toward the south, 

• Other soft- sediment features, including clastic dikes, 

slump glide plane surfaces, and dewatering structures 

– none of these structures penetrate the beds above or 

below the DZ, 

• Local deposits of charcoal and fragmented plant 

material, and 

• Flat lying and conformable strata along the scoured 

upper DZ surface. 

Similar soft- sediment disruption has been documented 

after hurricanes or tsunamis along coastal regions. 

However, the disruption across such a large region 

within the Western Interior Seaway suggests that 

something possibly larger than a storm or earthquake 

formed the DZ (Terry et al. 2004). The origin of the DZ 

soft- sediment deformation may correspond with some 

yet unknown late Cretaceous impact or it may simply be 

the result of a regional geotectonic event. More answers 

may come from research that continues into the 

biostratigraphy and magnetostratigraphy of the South 

Dakota DZ sections (Terry et al. 2004). 

Paleosols 

In Badlands National Park, ancient soil profiles 

(paleosols) developed on the changing landscape (fig. 7). 

The Yellow Mounds paleosol formed partly on the 

Upper Cretaceous Fox Hills Formation and partly on the 

Upper Cretaceous Pierre Shale where the Fox Hills 

Formation had been eroded (Retallack 1983; Stoffer 

2003). A cut bank along a tributary of Sage Creek in the 

Grassy Tables Overlook displays the unconformable 

relations between the green shale of the Fox Hills 

Formation, the Yellow Mounds paleosol, the reddish 

flood plain deposits of the Chamberlain Pass Formation, 

and the gray clay and siltstone of the Chadron Formation 

(Stoffer 2003). 

The Yellow Mounds paleosol is a thick, very strongly 

developed paleosol with a yellow, sandy horizon that 

overlies a red, silty- claystone, large clay- filled root 

channels, and a calcareous layer at depth (Retallack 

1983). The Yellow Mounds paleosol was well drained 

with a low water table. Paleosols in the Yellow Mounds 

series are complex with considerable relict bedding, 

possible re- sorted paleosol material, and buried 

horizons. Located at a major regional unconformity with 

about 25 m (82 ft) of erosional relief, the Yellow Mounds 

silty clay loam paleosol developed on a moderately hilly, 

rolling terrain. The size and deep penetration of root 

casts in the Yellow Mounds paleosol indicate that forests 

of large trees grew in the region (Retallack 1983). 

The Interior paleosol, part of the Chamberlain Pass 

Formation, is a red soil that reflects higher oxygenating 

conditions than were present during weathering of the 

Yellow Mounds paleosol (Stoffer 2003). The red soil 

stands out in contrast to the gray floodplain sediments of 

the overlying Chadron Formation. An abundance of 

fossil termite nests and other burrows occur locally 

throughout the Interior paleosol in the Grassy Tables 

Overlook exposure belt. 

The Yellow Mounds and Interior paleosols record sea 

level fluctuations in the Badlands region. A eustatic sea 

level fall led to pedogenic modification of the Pierre 

Shale and the formation of the Yellow Mounds paleosol 

series. Local subsidence caused a subsequent sea level 

rise, which backfilled stream channels and deposited the 

channel sandstone and overbank mudstone facies of the 

Chamberlain Pass Formation. Lateral changes within 

Chamberlain Pass paleosols indicate proximal and distal 

floodplain settings that have distinctive pedological 

characteristics (Terry, Jr. and Evans 1994). 

The paleo- Red River valley incised into the landscape 

when relative sea level again lowered. Sea level lowering 

led to intensified pedogenic modification of the 

Chamberlain Pass Formation and the Interior paleosol 

series (Retallack 1983; Terry, Jr. and Evans 1994; 

Ashworth et al. 1996). When sea level rose again, the 

valley backfilled with the Chadron Formation. 

Fossil remains and paleosols in the Eocene Chadron 

Formation and Oligocene Brule Formation record a 

change from forested uplands to dryer savannah- like 

environments in Badlands National Park (Benton et al. 

2001; Stoffer 2003). The Eocene and early Oligocene 

contained widespread woodlands with interspersed 

streams or marsh areas, but by the end of the Oligocene, 

cooler and drier conditions prevailed (Retallack 1983; 

Wall and Hauptman 2001). 

Other stratigraphic and sedimentary features 

The Verendrye Member of the Pierre Shale is a gray 

shale interval that contains abundant limestone 

concretions between the underlying Degrey Member 

and the overlying bentonitic shale beds of the Virgin 

Creek Member of the Pierre Shale. The Verendrye 

Member is exposed along Cedar Creek in the South Unit 

and along Sage Creek in the North Unit. The limestone 

concretions are septarian (containing an irregular 

polygonal pattern of internal cracks) and many display 

fossil debris or preserve the mostly broken shells of a 

variety of marine invertebrates and an abundance of 

bioturbation structures (Stoffer 2003). 

The concretions may be gutter casts, sedimentary 

structures that down- bulge the bottom of a sedimentary 
 NPS Geologic Resources Division 16 

bed. In cross- section they take the form of a small 

channel that may be a meter or more in length. Gutter 

casts are commonly interpreted as features of highenergy events in which storm or wave- generated 

currents erode bottom surfaces (Duke 1990; Myrow 1992; 

Graham and Ethridge 1995). Bioturbation data and gutter 

casts can provide information about water depth, oxygen 

availability on the seabed, and the orientation of the 

paleo- shoreline. 

An unconformity separates the marine shale of the Fox 

Hills Formation from the underlying Elk Butte Member 

of the Pierre Shale. Highlighting this unconformity is an 

ironstone concretion layer. Large, brown weathered, 

ironstone concretions in sandy mudstone and shale crop 

out on the hilltops around the Sage Creek Campground 

(Stoffer 2003). 

The Rockyford Ash defines the base of the Oligocene 

Sharps Formation. The ash bed forms a white, massive 

resistant, ledge- forming cap rock. An example of the ash 

bed can be seen at the Pinnacles Overlook area. The ash 

is from tremendous pyroclastic flows (ignimbrites) that 

erupted from volcanoes in the Great Basin region, 

episodically blanketing the Badlands area with ash 

(Stoffer 2003). 

Gravel deposits on some of the highest tablelands in the 

park area consist of materials carried by fast- moving 

streams flowing away from the Black Hills. These 

deposits are called the Medicine Root Gravel and are 

about 2 million years old. They were deposited prior to 

or near the beginning of the Pleistocene Ice Age. 

Structural Features 

Folds and faults 

The geologic setting of the Badlands National Park 

North Unit is controlled partly by the Sage Creek 

anticline, or Sage Creek Arch, a southeast- tonorthwest- trending system of folds and faults that is one 

of the region’s more prominent geological structures. 

The eastern end of the Sage Creek Arch begins in the 

eastern end of the North Unit in the vicinity of the Big 

Badlands. It is partly responsible for the south- facing 

Badlands escarpment. The crest of the anticline parallels 

the park’s Badlands Loop Road and the Sage Rim Road 

in the western part of the North Unit. The anticline 

looses its surficial expression west of Sage Creek. The 

upper drainages of Conata Creek along the Badlands 

Loop Road offer the best views of the anticline. In the 

Grassy Tables Overlook area, small hills in the Yellow 

Mounds and Interior paleosols mark the crest of the Sage 

Creek anticline (Stoffer 2003). 

Faults in Badlands National Park mainly display offsets 

in the range of several meters (feet). Northwest of the 

Conata Basin Overlook, a normal fault that puts Fox 

Hills adjacent to Chadron Formation has about 10 m (30 

ft) of displacement. Along Sage Creek, north of the Sage 

Rim Road Bridge, a normal fault cuts Pierre Shale beds. 

Total displacement along this fault is about 50 m (160 ft), 

but whether the offset is a result of faulting related to the 

Sage Creek Arch or to a deep- seated slump is not clear. 

West of the Roberts Prairie Dog Town, a reverse fault 

with about 20 m (66 ft) of offset juxtaposes Chadron 

Formation adjacent to strata of the Fox Hills Formation 

(Stoffer 2003). 

The Dillon Pass fault is believed to be part of a series of 

northwest- trending normal faults as much as 30 km (19 

mi) in length that define the northern boundary of a 40 

km (25 mi) wide asymmetrical basin (Ashworth et al. 

1996). Displacement along this fault can be seen in the 

misalignment of banding in the Brule Formation. Other 

northwest- trending normal faults can be seen at 

Norbeck Pass and along both sides of SD 240 between 

the Interior Road turnoff and the Cedar Pass Visitor 

Center (Ashworth et al. 1996). 

Unconformities 

Unconformities mark substantial gaps in time between 

rock units. If the strata beneath an unconformity is tilted 

at an angle relative to the overlying strata, the 

unconformity is called an ‘angular’ unconformity. An 

angular unconformity between tilted Fox Hills 

Formation strata and the overlying Chadron Formation 

is visible along a cut bank of upper Conata Creek (Stoffer 

2003). The angular unconformity suggests that the 

Cretaceous Fox Hills Formation was deformed (tilted) 

and eroded prior to the deposition of the Eocene 

Chadron Formation. Deformation was related to the 

growth of the Sage Creek anticline, and the angular 

unconformity indicates that the anticline was already 

developing before late Eocene time. 

Clastic dikes 

Prominent clastic dikes, located directly southwest of the 

SD 240- Old NE Road junction, run nearly perpendicular 

to the surrounding horizontal layers (fig. 10). Clastic 

dikes typically form when vertical cracks caused by 

sediment shrinkage and compaction fill with sediment, 

which subsequently hardens to form sedimentary rock. 

The dikes at Badlands, especially in the North Unit, 

contain a large component of ash, which suggests that 

the Rockyford Ash may be a potential source of the 

sediment. However, many of the dikes continue through 

the Rockyford Ash horizon indicating that additional 

sediment must also have contributed to the vertical crack 

(Ashworth et al. 1996). 

In the South Unit, near the town of Scenic, groundwater 

circulating through the dikes has deposited silica cement 

making the dikes more resistant to erosion than the 

surrounding strata. The silica is in the form of brown 

chalcedony. Native Americans used chalcedony, a 

cryptocrystalline variety of quartz, for spear points, tools 

and arrowheads since the time of the Paleo- Indians 

(Weedon 1990; Kiver and Harris 1999). 

Because they are relatively resistant to erosion, the dikes 

often form straight ridges that project above the 

surrounding sedimentary rocks. These features can be 

seen at Homestead Overlook and at the Pinnacles 
 BADL Geologic Resource Evaluation Report 17

Overlook area (Kiver and Harris 1999; Stoffer 2003). 

Numerous clastic dikes crosscut the upper Scenic 

Member of the Brule Formation and the Sharps 

Formation. 

Clastic dikes that have been mapped along two major 

linear trends suggest that the clastic dikes might occupy 

fracture sets rather than simple cracks opened by 

sediment desiccation (Ashworth et al. 1996). More 

research is needed to explain the origin of these clastic 

dikes. 

Geoarcheology 

In Badlands National Park an active area of research is 

geoarcheology, the application of earth science 

techniques to the study of archaeological questions 

(Kuehn 2002). Researchers who study soil horizons in 

individual Quaternary stratigraphic sections describe the 

horizon in detail, age date the minerals, and analyze the 

horizon for potential cultural sites. A recent study 

(Kuehn 2002) analyzed eight stratigraphic sections 

selected from the following land surface categories: 

• Upper Prairie surface and the Wall 

• Pleistocene (?) Cheyenne River terraces 

• Early Pleistocene or late Tertiary surface 

• Lower Prairie surface 

All three sections from the Upper Prairie surface and 

from the Wall are associated with sod tables. A Late 

Prehistoric hearth filled with broken pieces of firecracked rock, mammal bone, and abundant fragments of 

charcoal was dated at 1435 ± 210 years B.P. The oldest 

archaeological remains are associated with Paleo- Indian 

traditions and are found at sites located in the South Unit 

on top of an early Pleistocene- Tertiary plateau surface 

and from a gravel- covered sod table on the Upper 

Prairie surface. Sod tables on the Upper Prairie surface 

also are associated with two of the eight previously 

recorded Late Plains Archaic and Pelican Lake sites 

(Kuehn 2002). Data suggest that the Upper Prairie 

surface near the edge of the Wall has generally good 

potential for Late Prehistoric, Archaic, and Paleo- Indian 

sites. 

The early Pleistocene or late Tertiary plateau surfaces are 

most common in the South Unit of Badlands National 

Park and contain extensive mantles of loess (eolian silt) 

and sand. Loess unconformably overlies silty loam in a 

section at Sheep Mountain Table and Pleistocene 

Medicine Root Gravel in a section at Cuny Table. The 

eolian deposits have the potential to contain 

archaeological materials dating from Paleo- Indian 

through the Late Prehistoric. These upland settings have 

sediment records that span the late Pleistocene through 

the Holocene, some of the most complete sediment 

records of any major landform category in the White 

River Badlands (Kuehn 2002). 

The Lower Prairie surface includes all landforms situated 

below the Wall such as previously active and currently 

active floodplains and the channels of today’s streams 

and gullies. The landforms vary considerably in age and 

elevation. In Sage Creek Basin charcoal dated at 2870 ± 

90 yr B.P. has been found in a channel incised into older 

terrace deposits and into the Pierre Shale. A complete 

bison vertebra was recovered from planar- laminated 

sand deposits and yielded an age of 5900 ± 250 yr B.P. In 

addition, two Late Archaic sites were found in prominent 

slump block deposits just below the top of the Wall 

(Kuehn 2002). 

Kuehn’s study was a preliminary search for relationships 

between geologic, geomorphic, and landform sequences 

and the distribution and preservation of archaeological 

sites in Badlands National Park. The data suggest that 

additional work is needed to describe the prehistoric and 

historic use of the badlands, the role of badland 

environments in the settlement pattern of seasonally 

mobile hunter- gatherer groups, and other cultural 

aspects of the culture of the region’s oldest inhabitants. 
 NPS Geologic Resources Division 18 

Figure 7. Badlands topography and paleosols at Badlands National Park. The red bands are paleosols in the Brule Formation. Typical 

badlands topography of sharply eroded buttes and pinnacles. Photo courtesy of Brian Franzone http://academic.wsc.edu/faculty/raberto1/ 

explorers_club/black_hills_pix/blackhills_photos_page_2.html (access August 20, 2007). 
 BADL Geologic Resource Evaluation Report 19

Figure 8. The Wall at Badlands National Park. The Wall separates the upper grassland from the lower grassland prairies. Reddish bands are 

paleosols. Photo courtesy of Brian Franzone http://academic.wsc.edu/faculty/raberto1/explorers_club/black_hills_ 

pix/blackhills_photos_page_2.html (access August 20, 2007). 
 NPS Geologic Resources Division 20 

Figure 9. Titanothere skeleton, South Dakota School of Mines and Technology museum, http://www.sdsmt.edu/services/museum/bronto.gif 

(accessed August 17, 2007). 

Figure 10. Clastic dike in Badlands National Park. Note that the dike is composed of material that is more resistant to erosion than the 

surrounding strata. 
 BADL Geologic Resource Evaluation Report 21

Map Unit Properties 

This section identifies characteristics of map units that appear on the Geologic Resource 

Evaluation digital geologic map of Badlands National Park. The accompanying table is 

highly generalized and is provided for background purposes only. Ground- disturbing 

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

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

digital geologic map or by contacting the National Park Service Geologic Resources 

Division. 

This section explains specific properties associated with 

different rock units that the park should be aware of 

when making resource management decisions. Geologic 

features and processes often occur in or can be restricted 

to a particular stratigraphic unit (group, formation, or 

member). The geologic units in the following table and 

their geologic features and properties correspond to the 

units found in the accompanying digital geologic data. 

Source data for the GRE digital geologic map are from: 

Raymond, W.H. and King, R.U., 1976, Geologic map of 

Badlands National Park and Vicinity, West- Central 

South Dakota: U.S. Geological Survey Miscellaneous 

Investigations Map I- 934, scale 1:62,500. 

King, R. U., and Raymond, W. H., 1971, Geologic map of 

the Scenic area, Pennington, Shannon, and Custer 

Counties, South Dakota: U.S. Geological Survey 

Miscellaneous Investigations Map I- 662, scale 

1:24,000., and 

Ellis, M.J., and Adolphson, D.G., 1971, Hydrogeology of 

the Pine Ridge Indian Reservation, South Dakota: U.S. 

Geological Survey Hydrologic investigation Atlas HA357 , scale 1:125,000. 

The following table presents a list of units exposed in 

Badlands National Park and features for each map unit. 

This table includes several properties specific to each 

unit present in the stratigraphic column including: age, 

map unit name and symbol, unit description, 

topographic expression, resistance to erosion, 

paleontologic and cultural resources, hazards and 

suitability for development.

 BADL Geologic Resource Evaluation Report 25

Geologic History 

This section describes the rocks and unconsolidated deposits that appear on the digital 

geologic map of Badlands National Park, the environment in which those units were 

deposited, and the timing of geologic events that created the present landscape. 

This section provides a more detailed description of the 

structure, tectonics, depositional and erosional history, 

and general stratigraphy of Badlands National Park and 

the surrounding area. The sedimentary rock layers 

exposed in the park are only a fraction of the thick 

sediment package that was deposited in the high Great 

Plains region. These sedimentary rocks overlie an ancient 

crust consisting of igneous and metamorphic rocks, 

similar to those exposed in the core of the Black Hills. 

Thee ancient basement rocks are billions of years old and 

form the North American craton. Wells drilled for water 

and petroleum show that the thickness of sedimentary 

rock above the basement varies throughout the region. 

Over time some areas subsided, forming basins, while 

others rose forming domes or plateaus. Since the 

Precambrian (fig. 11), shallow have seas advanced and 

retreated many times across the region around Badlands 

National Park. The sedimentary cover in some of these 

basins, such as the Williston Basin in North Dakota and 

Montana and the Powder River Basin in Wyoming, is 

more than 4,000 m (13,000 ft) thick. In the Badlands area, 

however, the sedimentary cover is only about 980 m 

(3,200 ft) thick. 

The rock record of the Paleozoic Era (251- 542 Ma), is not 

exposed at Badlands National Park, but in the subsurface 

it is dominated by limestone formed from calcareous 

sediments deposited in shallow seas (fig. 12). Uplift of the 

Ancestral Rocky Mountains in the late Paleozoic 

generated large quantities of clastic sediments (mostly 

sand and clay) that filled basins across the region (fig. 13). 

Additional sediments were episodically deposited across 

the badlands area of South Dakota during the Triassic 

and Jurassic Periods of the Mesozoic Era. By the Early 

Triassic, the process of plate tectonics had assembled all 

of the large landmasses around the globe into one large 

supercontinent, Pangaea. Soon after forming, however, 

Pangaea began to split apart and the lithospheric plates 

moved away from one another. Rivers draining westward 

from the Appalachian region flowed into a low, subdued 

mid- continent landscape. On the west coast of North 

America, the Cordilleran mountain belt was actively 

developing, and ongoing volcanism and mountain 

building began the events that would lead to the 

formation of the Western Interior Seaway in the 

Cretaceous Period. 

Cretaceous Period 

As mountain building occurred along the west coast of 

North America, about 115 Ma (Early Cretaceous), the 

region east of the mountains gradually subsided and 

eventually formed a broad, shallow inland sea. At its 

maximum extent roughly 80 Ma, this Western Interior 

Seaway extended from the present Wyoming- Idaho 

border to perhaps the Mississippi Valley region and from 

the Arctic Ocean to the Gulf of Mexico (fig. 14) (Stoffer 

2003). The oldest rocks exposed at the surface in 

Badlands National Park formed from sediments 

deposited about 75 Ma in the Western Interior Seaway. 

Cretaceous rocks in Badlands National Park preserve a 

history of gradual changes in sea level and also record the 

evolution of marine species and environmental changes. 

Two formations, the Pierre Shale and the lower part of 

the overlying Fox Hills Formation, represent the Upper 

Cretaceous in the park. 

Pierre Shale: In the Late Cretaceous, between 80 and 60 

Ma, the silts and muds of the Pierre Shale were deposited 

in the Western Interior Seaway (Harris et al. 1997; Stoffer 

2003). The fossils and sedimentary features in the Pierre 

Shale reveal subtle changes in the conditions of the 

seaway. At times, the seaway supported diverse marine 

fauna that lived both in and on the seabed, or swam 

above in the water column. Waves and currents mixed 

the seawater when sea level was relatively shallow, 

allowing oxygen- rich water to support a large variety of 

fauna. Preserved in the sediments that accumulated 

during periods of low- standing sea level is a mix of 

shelled mollusks (mostly clams and ammonites); 

arthropods; and, rare bones, teeth, and scales of fish and 

swimming reptiles. Traces of burrows and tracks of 

bottom fauna also are preserved. 

At other times, when the seaway was either deeper or 

stagnant, conditions in the seaway became hypoxic 

(oxygen- depleted) and inhospitable to many organisms, 

including invertebrates living in the seabed. In these 

hypoxic intervals, ammonite shells are relatively scarce, 

but where they occur they tend to be more complete 

because they were not subjected to bioturbation. Shell 

material in some beds provides evidence of massive dieoffs. Storms or upwelling events may have mixed the 

water column, robbing the little available oxygen in the 

thin oxygenated zone near the surface, and suffocating 

most of the organisms (Stoffer 2003). 

Different species migrated into the seaway from either 

the Gulf of Mexico or from the Arctic region. Eventually, 

the new arrivals either died off or adapted and became 

endemic to the seaway. Cretaceous ammonites in the 

Pierre Shale and Fox Hills Formation provide excellent 

documentation of evolution, competition, and 

environmental change through time. Ammonite species 
 NPS Geologic Resources Division 26 

that were abundant, yet short- lived, provide a useful 

marker bed for mapping and correlating layers of 

Cretaceous sedimentary rock. 

Fox Hills Formation: The lower three units of the Fox Hills 

Formation (Trail City Member, Timber Lake Member, 

and Enning Member) record the final Cretaceous 

deposition in the Badlands National Park region. The 

Fox Hills Formation is recognized as a complex series of 

marine, transitional, and terrestrial environments that 

interfinger across the Western Interior region (Stoffer 

2003). In Badlands National Park, however, these lower 

three units contain ammonites, indicating a marine 

environment of deposition. 

Assemblages of chondrichthian teeth from the Timber 

Lake Member of the Fox Hills Formation (fig. 3) suggest 

a diverse, marine and transitional, nearshore ecosystem 

in the Maastrichtian Stage of South Dakota (Becker et al. 

2004). The teeth and other fossils are found in small 

discontinuous lag deposits in clean, well- sorted, medium 

to fine quartz sands with hummocky and high- angle 

tangential cross- stratification. The geometry of the 

cross- beds and flow directions measured from the 

cross- beds suggest a complex interaction of storms, 

wave action, and tides. This type of depositional 

environment is common in shoreface marine 

environments. Ophiomorpha burrows, coarse- grained 

vertical burrows common to the Skolithos ichnofacies, 

and wood fragments found in the sand also support an 

interpretation of a shoreface depositional setting at this 

time (Becker et al. 2004). 

Transitional marine chondrichthian assemblages are the 

youngest yet recovered from Cretaceous rocks of the 

Western Interior. The Cretaceous assemblages are so 

different from chondrichthians recovered from 

Paleocene deposits in North Dakota that researchers 

hypothesize that there was a significant turnover among 

Western Interior chondrichthians during the interval 

between the deposition of the Upper Cretaceous and 

Paleocene units (Becker et al. 2004). The cause of this 

extinction is yet to be explained. The regional Disturbed 

Zone that contains large- scale slump- roll structures, 

clastic dikes, flame structures, and massive, homogenized 

beds supports the notion that a major deformation event 

occurred in the Late Cretaceous. 

Body fossils are scarce in an unnamed marine facies of 

the upper Fox Hills Formation (fig. 3) but marine trace 

fossils are common (Stoffer 2003). The types of trace 

fossils found in this facies represent the lower intertidal 

zone to shallow subtidal zone of the both Skolithos and

Cruziana ichnofacies (Pemberton et al. 1992; Stoffer 

2003). 

The Yellow Mounds paleosol developed on an erosional 

surface on both the Pierre Shale and the Fox Hills 

Formation (Rachel Benton, NPS paleontologist, 

Badlands National Park, written communication June 27, 

2006). Badlands is at the very southern exposure of the 

Fox Hills Formation in the region so Fox Hills strata only 

occur sporadically in the park along the northern 

margins. The orange “Yellow Mounds” consist of soils 

and (or) reworked soil that may have been associated 

with mixed brackish and freshwater environments. 

Tertiary Period 

During the early Tertiary, the Badlands area was near sea 

level and brackish inland seas and lakes still existed 

throughout the Western Interior region. The Laramide 

Orogeny that began in the Late Cretaceous and 

continued through mid- Tertiary resulted in the rise of 

the Rocky Mountains, including the Black Hills (fig. 15). 

Forests gave way to savannah or steppes as the climate 

became drier (Stoffer 2003). Rivers spread sediments 

over vast expanses of the exposed plains. In a final phase 

of volcanism at the end of the Laramide Orogeny, white, 

airborne- volcanic ash rained down upon the region. 

Sand, silt, and clay, mixed and interbedded with volcanic 

ash, stacked up thousands of meters thick. Arid 

conditions existed by the close of the Tertiary. 

Chamberlain Pass Formation: The Eocene Chamberlain 

Pass Formation crops out along an unconformable 

surface between the top of the Pierre Shale (Yellow 

Mounds) and the bottom of the Chadron Formation 

(Terry, Jr. and Evans 1994; Stoffer 2003). The 

Chamberlain Pass Formation in Badlands National Park 

consists of floodplain deposits that lack gravel and so is 

indistinguishable from the Interior paleosol. 

The Interior paleosol separates the Chamberlain Pass 

Formation from the overlying Chadron Formation. In 

contrast to the Yellow Mounds paleosol, the red Interior 

paleosol reflects higher oxygenating conditions. The 

abundant fossil termite nests and other burrows found in 

the Interior paleosol support this interpretation. 

Chadron Formation: The poorly consolidated mudrocks 

of the Chadron Formation are also Eocene in age (fig. 3). 

The strata were originally named the “Titanotherium

beds” for the abundance of bones of Titanotherium, large 

rhinoceros- like mammals found by early investigators. 

The high bentonitic- clay content becomes sticky, 

impervious and plastic when wet and dries to a popcorn 

texture, making the surface an inhospitable environment 

for most vegetation. 

The gravel and sand in the formation consist of chert, 

granitic rocks, and metamorphic materials that probably 

derived from streams draining the core and surrounding 

sedimentary outcrop belts of the Black Hills region. 

Freshwater limestone beds that occur intermittently in 

the lower part of the Chadron Formation contain fish 

and plant remains. 

Bones, invertebrate remains, plant material, root traces, 

animal burrows, coprolites, animal tracks, fossil soils, 

and sedimentary deposits are typical of stream and 

floodplain deposits that include shallow, warm water 

lakes (Stoffer 2003). The fossil remains in the Chadron 

Formation are consistent with a forested floodplain with 
 BADL Geologic Resource Evaluation Report 27

scattered sedge meadows, oxbow ponds, and forested 

upland environments. 

Brule Formation: The alternating rusty- red and grayishwhite strata of the Brule Formation are derived from 

stream and floodplain deposits that accumulated during 

the early part of the Oligocene Epoch. The Scenic 

Member records a series of reddish paleosols that 

formed on a broad, aggrading floodplain in which land 

turtles and oreodonts were common (Stoffer 2003). 

Tuffaceous mudstones were derived from the alteration 

of volcanic glass that fell onto the Great Plains as dust 

(Evanoff and Terry, Jr. 2004). The broadly undulatory 

contact at the base of the Scenic Member has as much as 

24.5 m (80.4 ft) of relief, reflecting an erosional 

topography cut into the underlying Chadron Formation. 

During the time that sediment was deposited forming the 

Scenic Member, paleovalleys filled with light- gray 

sandstones that coalesced into broad blankets of fluvial 

deposits. These blankets of sand are capped by thin, very 

widespread mudstones that extend along the entire 

length of the Wall and are important marker beds. 

The mudstone markers are paleosols and represent a 

temporary shift from active fluvial deposition to slow 

accumulation and weathering of volcanic dust. The 

mudstones are similar to modern Alfisols, mineral soils 

developed under forests in temperate, humid climates. 

The paleosols that formed between individual marker 

beds are thinner, less well developed, and are similar to 

modern Entisols, and Inceptisols, mineral soils that are 

not well developed and are characterized by relatively 

non- distinct layers (Evanoff and Terry, Jr. 2004). 

The shift from mudstone beds to thick siltstone beds 

marks the contact between the Scenic Member and the 

overlying Poleslide Member. Reworked eolian 

volcaniclastics and occasional fluvial channel and 

overbank deposits record a change from wet, subhumid 

conditions where the volcaniclastic dust was weathered, 

to drier semiarid conditions where the dust accumulated. 

(Evanoff and Terry, Jr. 2004; Terry, Jr. and Kosmidis 

2004). Retallack (1983) documented 31 paleosols in the 

Poleslide Member, these define periods of landscape 

stability during which eolian input was reduced. 

Larger stream channels developed as conditions became 

drier in the mid to late Oligocene. Continuous streams 

became more ephemeral, and episodic flood events 

replaced deposition by perennial streams. Many species 

adapted to open plain environments and became more 

dependent on water holes for survival. 

One of these watering holes may have been a lake that 

formed in the Badlands region. The lake contained 

charophytes (green algae), aquatic snails, stromatolites, 

and fish and covered several hundred square meters 

(Terry, Jr. and Kosmidis 2004). The paleoclimatic 

interpretation of associated paleosols suggest that the 

lake was probably spring fed. 

Sharps Formation: The overall change in geologic and 

environmental conditions that began 28 to 26 Ma is 

reflected in the Sharps Formation (Stoffer 2003). During 

the time of deposition of the Sharps Formation, the 

region became even drier. The Badlands region was 

episodically blanketed by voluminous ash- fall deposits 

associated with tremendous ignimbrite- type volcanic 

eruptions in the Great Basin region. The tuffaceous 

sandstones, stream channel sands, and floodplain muds 

are typical of steppe or even desert- like conditions. 

The region that is now the White River Badlands 

supported many kinds of animals during the Oligocene 

Epoch approximately 34 to 23 million years ago. The land 

was lush, well watered, and warmer than it is now. 

Animals roamed the floodplains and were sometimes 

trapped in floods and quickly buried in river sediments. 

Preservation was excellent so that the Oligocene beds in 

Badland National Park are one of the world’s most 

prized vertebrate fossil sites. 

Medicine Root Gravel: The Medicine Root Gravel that 

caps the highest upland areas in the Pinnacles Overlook 

area is the youngest Tertiary- age sedimentary deposit in 

Badlands National Park (Stoffer 2003). The gravels are 

stream terrace deposits that probably were originally 

derived from fast- flowing streams draining the core of 

the Black Hills about 2 Ma. During dryer periods of the 

Pleistocene, eolian dust deposits accumulated on top of 

the gravel deposits. 

Quaternary Period 

Although the Badlands National Park region was not 

directly impacted by continental glaciation during the 

Pleistocene, the continental glaciers impacted the 

landscape because of their influence on regional river 

systems (fig. 16). Before the Pleistocene Ice Age, western 

interior rivers flowed north into the Hudson Bay region. 

As continental ice sheets blocked the north- flowing 

rivers, large lakes formed along the ice front. Eventually 

the water breached the divides and modern river systems 

evolved with the Missouri and Ohio Rivers merging with 

the Mississippi River system. In general, the Missouri 

River follows the southwestern boundary of the last 

major glaciation. 

Prior to glaciation, the north- flowing rivers probably 

had a gentler stream gradient than that of the Missouri 

River when it formed along the southern ice front. The 

Missouri River has carved a gorge about 91 m (300 ft) 

deep for most of its length across the western interior 

region, and this downcutting has been gradually 

translating upstream into the headwaters of all its 

tributaries. This downcutting is producing the relief seen 

in the badlands region (Stoffer 2003). 

The rate of downcutting has not been equal across the 

region. The Cheyenne River captured all the major 

streams draining from the Black Hills region, as 

evidenced by the dry, low divides between the White 

River and Cheyenne River valleys throughout the 

western part of the park. 
 NPS Geologic Resources Division 28 

Through the Quaternary, the Cheyenne, White, and Bad 

Rivers and their tributaries have gradually carved into 

the plateau that includes Badlands National Park. Stream 

capture and erosion have created a landscape of mesas 

and rock pinnacles. Erosion has gradually carved back 

the bounding escarpments or “walls” of this plateau. 

Today’s badlands landscape reflects factors and 

conditions related to the physical character of the rocks 

as well as climate. The volcanic ash at Badlands National 

Park is easily eroded and succumbs quickly to erosion as 

the Wall retreats northward into the upper plain, which 

is the original land surface (fig. 8). As the ash is eroded, 

the more durable underlying beds of the Brule 

Formation are exposed. Slender spires, knife- sharp 

ridges, and intricately creased slopes of Badlands 

National Park result from the erosion of the steeper 

slopes (fig. 8). The softer mudstone of the Chadron 

Formation forms more rounded ridges and spurs and 

gentler slopes than the Brule Formation. 

Like the character of the bedrock, climate is an 

important factor with regard to weathering and erosion 

processes. The combination of high summer 

temperatures, short intense rain events, and dry, cold 

winters make growing conditions difficult for most 

vegetation. The harsh, soil- free conditions around the 

badlands also limit growth. 

Heavy rainfall from thunderstorms flows as sheet wash 

across the barren land surface, forming rills and rivulets, 

and eventually flows into stream channels. Sediment, 

loosened by the heavy rainfall, washes into streams. Mass 

wasting, such as slumping and rock falls, contributes 

sediment directly to stream channels. With erosion rates 

in the barren terrain as much as 2.54 cm (1.00 in) of 

sediment per year, the landscape of Badlands National 

Park is constantly changing. 
 BADL Geologic Resource Evaluation Report 29

Figure 11. Geologic time scale adapted from the U.S. Geological Survey and International Commission on Stratigraphy. Absolute ages 

shown are in millions of years (Ma). Red lines indicate major unconformities between eras. Included are major events in life history and 

tectonic events occurring on the North American continent. Strata exposed at Badlands National Park include only the latest approximately 

75 million years of Earth history. 
 NPS Geologic Resources Division 30 

Figure 12. Paleogeographic map of the North American continent during the Late Devonian, approximately 360 Ma. Shallow seas (light blue) 

cover the Badlands National Park region. Subaerial topography is shown in shades of brown. Map courtesy of Dr. Ron Blakey, Northern 

Arizona University, available at http://jan.ucc.nau.edu/~rcb7/namD360.jpg (accessed August 21, 2007). 
 BADL Geologic Resource Evaluation Report 31

Figure 13. Paleogeographic map of the North American continent during the Late Permian, approximately 260 Ma. Streams transported 

sediments eroded from the Ancestral Rocky Mountains in Colorado into the Badlands National Park area where the final remnants of a 

shallow sea were disappearing. To the east, the plate tectonic collision of the African plate with North America resulted in the Alleghenian 

Orogeny. Map courtesy of Dr. Ron Blakey, Northern Arizona University, available at http://jan.ucc.nau.edu/~rcb7/namP260.jpg (accessed 

August 18, 2007). 
 NPS Geologic Resources Division 32 

Figure 14. Paleogeographic map of the North American continent during the Late Cretaceous, approximately 85 Ma. The Western Interior 

Seaway covers the Badlands National Park region. The mountain belt that stretches from Alaska to Mexico is a result of the Sevier Orogeny. 

Map courtesy of Dr. Ron Blakey, Northern Arizona University, available at http://jan.ucc.nau.edu/~rcb7/namK85.jpg (accessed August 21, 

2007). 
 BADL Geologic Resource Evaluation Report 33

Figure 15. Paleogeographic map of the North American continent during the Eocene Epoch of the Tertiary Period, approximately 40 Ma. 

Mountains in Colorado and Wyoming are the result of the Laramide Orogeny. Sediments eroded from these mountain ranges were deposited 

in the Badlands National Park area to form the Chamberlain Pass Formation. Map courtesy of Dr. Ron Blakey, Northern Arizona University, 

available at http://jan.ucc.nau.edu/~rcb7/namPe40.jpg (accessed August 20, 2007). 
 NPS Geologic Resources Division 34 

Figure 16. Paleogeographic map of the North American continent during the Pleistocene Epoch of the Quaternary Period, approximately 

0.126 Ma. The continental ice sheet does not impact the Badlands National Park region, but surface water from the Black Hills flows from 

west to east across western South Dakota. Map courtesy of Dr. Ron Blakey, Northern Arizona University, available at 

http://jan.ucc.nau.edu/~rcb7/namQ.jpg (accessed August 21, 2007). 
 BADL Geologic Resource Evaluation Report 35

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. 

aggradation (geomorph). The building- up of the Earth’s 

surface by deposition, specifically by a stream in order 

to establish or maintain uniformity of grade or slope. 

alluvium. Stream deposited sediment that is generally 

rounded, sorted, and stratified. 

angular unconformity. An unconformity where the strata 

above and below are oriented differently; generally 

caused by structural deformation and erosion of the 

lower units prior to deposition of the beds above the 

unconformity. 

anticline. A fold, generally convex upward, whose core 

contains the stratigraphically older rocks. 

ash (volcanic). Fine pyroclastic material ejected from a 

volcano (also see tuff). 

basement. The undifferentiated rocks, commonly 

igneous and metamorphic, that underlie the rocks of 

interest. 

basin (structural). A doubly- plunging syncline in which 

rocks dip inward from all sides (also see dome). 

basin (sedimentary). Any depression, from continental 

to local scales, into which sediments are deposited. 

bed. The smallest sedimentary strata unit, commonly 

ranging in thickness from one centimeter to a meter or 

two and distinguishable from beds above. 

bedding. Depositional layering or stratification of 

sediments. 

calcareous. A rock or sediment containing calcium 

carbonate. 

chalcedony. A cryptocrystalline variety of quartz. 

chondrichthian. Of or relating to vertebrates, especially 

fish, that have skeletons of cartilage rather than bone. 

clastic. Rock or sediment made of fragments or preexisting rocks. 

clastic dike. A sedimentary dike consisting of a variety of 

clastic materials derived from underlying or overlying 

beds. 

clay. Clay minerals or sedimentary fragments the size of 

clay minerals (<2 cm). 

craton. The relatively old and geologically stable interior 

of a continent (also see continental shield). 

cross-bedding. Uniform to highly- varied sets of inclined 

sedimentary beds deposited by wind or water that 

indicate distinctive flow conditions. 

crust. The outermost compositional shell of Earth, 10- 40 

km (6- 25 mi) thick, consisting predominantly of 

relatively low- density silicate minerals (also see 

oceanic crust and continental crust). 

deformation. A general term for the process of faulting, 

folding, shearing, extension, or compression of rocks 

as a result of various Earth forces. 

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. 

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

action of the wind. 

epoch. A geochronologic unit that is longer than a stage 

but shorter than a period; Paleocene, Eocene, and 

Oligocene are epochs. 

eustatic. Relates to simultaneous worldwide rise or fall 

of sea level in Earth’s oceans. 

facies (sedimentary). The depositional or environmental 

conditions reflected in the sedimentary structures, 

textures, mineralogy, fossils, etc. of a sedimentary 

rock. 

fault. A subplanar break in rock along which relative 

movement occurs between the two sides. 

flame structure. Wave- or flame- shaped plumes of mud 

preserved in sediment; probably formed by loadcasting of mud squeezed upward into an overlying 

layer. 

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, fault) 

frost wedging. The breakup of rock due to the expansion 

of water freezing in fractures. 

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. 

ichnofacies. A sedimentary facies characterized by a 

particular type of tracr fossil. 

ichnofossil. A trace fossil. 

igneous. Refers to a rock or mineral that originated from 

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

igneous, metamorphic, and sedimentary. 

ignimbrite. A pyroclastic flow deposit; welded tuff. 

joint. A semi- planar break in rock without relative 

movement of rocks on either side of the fracture 

surface. 

karst topography. Topography characterized by 

abundant sinkholes and caverns formed by the 

dissolution of calcareous rocks. 

Lamniformes. An order of sharks, also known as 

mackerel sharks, that includes familiar species of 

sharks, such as the great white, mako, and thresher 

sharks. 

landslide. Any process or landform resulting from rapid 

mass movement under relatively dry conditions. 

lithology. The description of a rock or rock unit, 

especially the texture, composition, and structure of 

sedimentary rocks. 
 NPS Geologic Resources Division 36 

loess. Silt- sized sediment deposited by wind, generally 

of glacial origin. 

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. 

metamorphic. Pertaining to the process of 

metamorphism or to its results. 

normal fault. A dip- slip fault in which the hanging wall 

moves down relative to the footwall. 

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. 

overbank deposits. Alluvium deposited outside a stream 

channel during flooding. 

paleogeography. The study, description, and 

reconstruction of the physical geography from past 

geologic periods. 

paleontology. The study of the life and chronology of 

Earth’s geologic past based on the phylogeny of fossil 

organisms. 

Pangaea (also spelled Pangea). A theoretical, single 

supercontinent that existed during the Permian and 

Triassic Periods (see Laurasia and Gondwana). 

pebble. Generally, small, rounded, rock particles from 4 

to 64 mm in diameter. 

pedogenic. Pertaining to soil formation. 

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

extent and elevation above the surrounding plains, 

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

plate tectonics. The theory that the lithosphere is broken 

up into a series of rigid plates that move over Earth’s 

surface above a more fluid asthenosphere. 

pseudokarst: A karst- like terrain having closed 

depressions, sinking streams, and caves, but produced 

by a process other than the dissolving of rock. 

reverse fault. A contractional, high angle (>45o), dip- slip 

fault in which the hanging wall moves up relative to the 

footwall (also see thrust fault). 

sandstone. Clastic sedimentary rock of predominantly 

sand- sized grains. 

scarp. A steep cliff or topographic step resulting from 

vertical displacement on a fault or by mass movement. 

scaphitid ammonite. An ammonite with an unusual 

coiling pattern that begins in a tight coil, then 

straightens out, and finally coils back towards the 

initial coil. 

sediment. An eroded and deposited, unconsolidated 

accumulation of lithic and mineral fragments. 

sedimentary rock. A consolidated and lithified rock 

consisting of detrital and/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. 

strata. Tabular or sheet- like masses or distinct layers 

(e.g., of rock). 

stratigraphy. The geologic study of the origin, 

occurrence, distribution, classification, correlation, 

age, etc. of rock layers, especially sedimentary rocks. 

stream piracy. The process by which active headward 

stream erosion breaches a drainage divide and 

intercepts part of an adjacent drainage basin. 

strike. The compass direction of the line of intersection 

that an inclined surface makes with a horizontal plane. 

subsidence. The gradual sinking or depression of part of 

Earth’s surface. 

taphonomy. The branch of paleoecology dealing with all 

processes that occur after the death of an organism 

until its discovery. 

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 flood plain(s), stream bed(s), and/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 fossil. Sedimentary structure, such as tracks, trails, 

burrows, etc., that preserve evidence of an organism’s 

life activities, rather than the organism itself. 

trend. The direction or azimuth of elongation or a linear 

geological feature. 

tuff. Generally fine- grained, igneous rock formed of 

consolidated volcanic ash. 

type locality. The geographic location where a 

stratigraphic unit is well displayed, is formally defined 

as a typical section, and derives its name. 

unconformity. A surface within sedimentary strata that 

marks a prolonged period of nondeposition or 

erosion. 

uplift. A structurally high area in the crust, produced by 

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. 

yardang. A long, irregular, sharp- crested, undercut ridge 

between two round- bottomed troughs, carved on a 

plateau or unsheltered plain in a desert region by wind 

erosion, and consisting of soft but coherent deposits. 
 BADL Geologic Resource Evaluation Report 37

References 

This section lists references cited in this report. A more complete geologic bibliography is 

available from the National Park Service Geologic Resources Division. 

Ashworth, Allan C., Rachel C. Benton, Robert F. Biek, 

Edward C. Murphy, George W. Shurr, Kimberlee K. 

Stevens, and Dennis O. Terry, Jr. 1996. A Field Guide 

to Tertiary Tectonism in the Northern Great Plains: 

Road Log, Field Trip 1. In Guidebook to the Geology of 

the Black Hills, South Dakota, edited by Colin J. 

Paterson and James G. Kirchner. Rapid City: South 

Dakota School of Mines and Technology, Bulletin No. 

19, 14- 18. 

Baker, C.L. 1951. Yardangs in South Dakota badlands. 

Boulder: Geological Society of America Bulletin, Vol. 

62, no. 12, pt. 2, abstract, 1532. 

Becker, Martin A., John A. Chamberlain, Jr., and Dennis 

O. Terry, Jr. 2004. Chondrichthians from the Fairpoint 

Member of the Fox Hills Formation (Maastrichtian), 

Meade County, South Dakota. Journal of Vertebrate 

Paleontology, Vol. 24, 780- 793. 

Benton, Rachel. 2003. The Big Pig Dig: Integrating 

paleontological research and visitor education at 

Badlands National Park, South Dakota. Journal of 

Geoscience Education, Vol. 51, 313- 316. Also available 

online at http://findarticles.com/p/articles/ 

mi_qa4089/is_200305/ai_n925857 (accessed August 21, 

2007). 

Benton, Rachel C., Emmett Evanoff, Carrie L. Herbel, 

and Dennis O. Terry, Jr. 2001. Baseline mapping of 

fossil bone beds at Badlands National Park. In 

Proceedings of the 6th Fossil Resource Conference, edited 

by Vincent L. Santucci and Lindsay McClelland. 

Denver: National Park Service, Geologic Resources 

Division Technical Report NPS/NRGRD/GRDTR01/01, 85- 94. Also available online at http://www2. 

nature.nps.gov/geology/paleontology/pub/fossil_conv

erence_6/benton.htm (accessed June 28, 2006). 

Benton, Rachel C., Emmett Evanoff, Carrie L. Herbel, 

and Dennis O. Terry, Jr. 2004. Paleontology, 

sedimentology and stratigraphy of the Poleslide 

Member, Brule Formation, Badlands Natonal Park. 

Boulder: Geological Society of America, Abstracts with 

Programs, Vol. 36, 53. 

Benton, Rachel C., Emmett Evanoff, Carrie L. Herbel, 

and Dennis O. Terry, Jr. 2006. Baseline mapping of 

fossil bone beds at Badlands National Park, South 

Dakota, Natural Resources Preservation Program 

Grant 2000- 2002. On file at Badlands National Park. 

Benton, Rachel C., Emmett Evanoff, Carrie L. Herbel, 

and Dennis O. Terry, Jr. In progress. Documentation 

of significant paleontological localities within the 

Poleslide Member, Brule Formation, Badlands 

National Park, South Dakota, Natural Resources 

Preservation Program Grant 2003- 2005. 

Bjork, P.R. 1994. First quarterly report on the Pig Wallow 

Site, Badlands National Park, South Dakota. 

Unpublished report of investigations, Badlands 

National Park Archives, 10 pages. 

Chamberlain, Jr., John A., Dennis O. Terry, Jr., Philip W. 

Stoffer, and Martin A. Becker. 2001. Paleontology of 

the K/T boundary interval: Badlands National Park, 

South Dakota. In Proceedings of the 6th Fossil Resource 

Conference, edited by Vincent L. Santucci and Lindsay 

McClelland. Denver: National Park Service, Geologic 

Resources Division Technical Report 

NPS/NRGRD/GRDTR- 01/01, 11- 22. 

Duke, W.L. 1990. Geostrophic circulation or shallow 

marine turbidity currents? The dilemma of paleoflow 

patterns in storm- influenced prograding shoreline 

systems. Journal of Sedimentary Petrology, Vol. 60, 

870- 883. 

Ellis, M.J. and D.G. Adolphson. 1971. Hydrogeology of 

the Pine Ridge Indian Reservation, South Dakota. U.S. 

Geological Survey Hydrologic Investigations Atlas, 

HA- 0357, scale 1:250,000. 

Evanoff, Emmett, and Dennis O. Terry, Jr. 2004. 

Architecture of the lower Oligocene Scenic Member of 

the Brule Formation in the north unit of Badlands 

National Park, South Dakota. Boulder: Geological 

Society of America, Abstracts with Programs, Vol. 36, 

99. 

Graham, John, and Frank G. Ethridge. 1995. Sequence 

stratigraphic implications of gutter casts in the Skull 

Creek Shale, Lower Cretaceous, northern Colorado. 

The Mountain Geologist, Vol. 32, 95- 106. 

Harris, Ann G., Esther Tuttle, and Sherwood D. Tuttle. 

1997. Geology of National Parks. Dubuque: 

Kendall/Hunt Publishing Company, 5th edition, 113- 126. 

Kiver, Eugene P., and David V. Harris. 1999. Geology of 

U.S. Parklands. New York: John Wiley & Sons, Inc., 5th

edition, 710- 718. 
 NPS Geologic Resources Division 38 

Kuehn, David D. 2002. Preliminary Geoarchaeological 

reconnaissance in Badlands National Park, South 

Dakota. El Paso: David Kuehn, Consultant, prepared 

for the National Park Service, 68 p. 

Larson, Edwin E., and Emmett Evanoff. 1998. 

Tephrostratigraphy and source of the tuffs of the 

White River sequence. Boulder: Geological Society of 

America, Special Paper 325, 1- 14. 

MacEachern, J.A., and S. George Pemberton. 1992. 

Ichnological aspects of Cretaceous shoreface 

successions and shoreface variability in the Western 

Interior Seaway of North America. In Applications of 

Ichnology to Petroleum Exploration, edited by S. 

George Pemberton. Calgary: SEPM (Society for 

Sedimentary Geology) Core Workshop No. 17, 57- 85. 

Mintz, Jason, Ashley Edelman, Dennis O. Terry, Jr., and 

Ryan Bright. 2005. Paleosols and vertebrate 

taphonomy of the Oligocene Poleslide Member, Brule 

Formation, Badlands National Park, South Dakota. 

Boulder: Geological Society of America, Abstracts with 

Programs, Vol. 37, 13. 

Myrow, P.M. 1992. Pot and gutter casts from the Chapel 

Island Formation, southeast Newfoundland. Journal of 

Sedimentary Petrology, Vol. 62, 992- 1007. 

National Park Service. 1998. Baseline water quality data 

inventory and analysis, Badlands National Park. Fort 

Collins: Water Resources Division, National Park 

Service, Technical Report NPS/NRWRD/NRTR98/161, 317 pages. Also available online at 

http://nrdata.nps.gov/BADL/nrdata/water/baseline_w

q/docs/BADLWQAA.pdf (accessed August 25, 2007). 

National Park Service. 2005. General Management 

Plan/Environmental Impact Statement Badlands 

National Park/North Unit. Denver: Department of the 

Interior, National Park Service, Denver Service Center, 

280 pages. Also available online at http://www.nps. 

gov/badl/pphtml/ documents.html (accessed January 

9, 2006). 

Palamarczuk, Susana, John A. Chamberlain, Jr., and 

Dennis O. Terry, Jr. 2003. Dinoflagellates of the fox 

Hills Formation (Maastrichtian), Badlands area of 

South Dakota: biostratigraphic and paleoenvironmental implications. St. Catharines, Canada, 

Joint meeting AASP/CAP/NAMS, not paginated. 

Pemberton, S. George, R.W. Frey, M.J. Ranger, and J.A. 

MacEachern. 1992. The conceptual framework of 

ichnology. In Applications of Ichnology to Petroleum 

Exploration, edited by S. George Pemberton. Calgary: 

SEPM (Society for Sedimentary Geology) Core 

Workshop No. 17, 1- 33. 

Raymond, W.H., and R.U. King. 1976. Geologic map of 

the Badlands National Monument and vicinity, westcentral South Dakota. U.S. Geological Survey 

Miscellaneous Investigations Series, Map I- 934, 

reprinted 1984, scale 1:62,500. 

Retallack, G.J. 1983. A paleopedological approach to the 

interpretation of terrestrial sedimentary rocks: the 

mid- Tertiary fossil soils of Badlands National Park, 

South Dakota. Boulder: Geological Society of America 

Bulletin 94, 823- 840. 

Schumm, Stanley A. 1956. The role of creep and rainwash 

on the retreat of badland slopes. American Journal of 

Science, Vol. 254, 693- 706. 

Stoffer, Philip W. 2003. Geology of Badlands National 

Park: A preliminary report. U.S. Geological Survey 

Open- File Report 03- 35, 62 pages. Also available 

online at http://geopubs.wr.usgs.gov/open- file/of03-

35.pdf (accessed September, 2005). 

Stoffer, Philip W., P. Messina, John A. Chamberlain, Jr., 

and Dennis O. Terry, Jr. 2001. The CretaceousTertiary boundary interval in Badlands National Park, 

South Dakota. U.S. Geological Survey Open- File 

Report 01- 056. 

Terry, Jr., Dennis O., and J.E. Evans. 1994. Pedogenesis 

and paleoclimatic implications of the Chamberlain 

Pass Formation, basal White River Group, badlands of 

South Dakota. Palaeogeography, Palaeoclimatology, 

Palaeoecology, Vol 110, 197- 215. 

Terry, Dennis O., Jr., and Paul Kosmidis. 2004. An 

Oligocene springfed carbonate lake in the middle of a 

volcaniclastic eolianite, Badlands National Park, South 

Dakota. Boulder: Geological Society of America, 

Abstracts with Programs, Vol. 36, 35. 

Terry, Dennis O., Jr., John A. Chamberlain, Jr., Phillip W. 

Stoffer, P. Messina, Patricia A. Jannett. 2oo1. Marine 

Cretaceous- Tertiary boundary section in 

southwestern South Dakota. Geology, Vol. 29, no. 11, 

1055- 1058. 

Terry, Dennis O., Jr., John A. Chamberlain, Jr., Philip W. 

Stoffer, Martin A. Becker, Patricia A. Jannett, Susana 

Palamarczuk, Matt Garb, and Brett Beeney. 2004. A 

widespread zone of soft sediment deformation and 

ejecta in the Fox Hills Formation of southwest South 

Dakota; an impactite without a crater. Boulder: 

Geological Society of America, Abstracts with 

Programs, Vol. 36, 90. 
 BADL Geologic Resource Evaluation Report 39

Wall, William P., and Jacqueline M. Hauptman. 2001. A 

craniodental interpretation of the dietary habits of 

Poebrotherium wilsoni (Camelidae) from the Oligocene 

of Badlands National Park, South Dakota. In 

Proceedings of the 6th Fossil Resource Conference, edited 

by Vincent L. Santucci and Lindsay McClelland. 

Denver: National Park Service, Geologic Resources 

Division Technical Report NPS/NRGRD/GRDTR01/01, 76- 82. 

Weedon, Ronald R. 1990. Badlands. In Natural History of 

the Black Hills and Badlands, by Sven G. Froiland. 

Sioux Falls: The Center for Western Studies, 

Augustana College, 177- 195. 

Wicander, R., and J.S. Monroe. 1993. Historical Geology. 

Minneapolis/St. Paul, West Publishing, 640 p. 
 NPS Geologic Resources Division 40 

Appendix A: Geologic Map Graphic 

The following pages are a preview or snapshot of the geologic maps for Badlands 

National Park. For poster- size PDFs of these maps or for digital geologic map data, 

please see the included CD or visit the Geologic Resource Evaluation publications Web 

page (http://www2.nature.nps.gov/geology/inventory/gre_publications). 
The Department of the Interior protects and manages the nation’s natural resources and cultural heritage; provides scientific and other 

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

Communities. 

Badlands National Park 

Geologic Resource Evaluation Report 

Natural Resource Report NPS/NRPC/GRD/NRR—2008/036 

NPS D-155, June 2008 

National Park Service 

Director • Mary A. Bomar 

Natural Resource Stewardship and Science 

Acting Associate Director • Mary Foley, Chief Scientist of the Northeast Region 

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 • Dave Steensen 

Planning Evaluation and Permits Branch Chief • Carol McCoy 

Credits 

Author • John Graham

Review • Rachel Benton and Carol McCoy 

Editing • Thomas W. Judkins, Sid Covington, and Melanie Ransmeier 

Digital Map Production • Stephanie O'Meara and Trista Thornberry-Ehrlich 

Map Layout Design • Melanie Ransmeier
Geologic Resources Division 

Natural Resource Program Center 

P.O. Box 25287 

Denver, CO 80225 

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

(303) 969-2090 

EXPERIENCE YOUR AMERICATM 

National Park Service 

U.S. Department of the Interior