Glacier National Park 

Geologic Resource Evaluation Report 

Natural Resource Report NPS/NRPC/GRD/NRR—2004/001 

National Park Service 

U.S. Department of the Interior 

Natural Resource Program Center 

Glacier National Park 

Geologic Resource Evaluation Report 

Natural Resource Report NPS/NRPC/GRD/NRR—2004/001 

Geologic Resources Division 

Natural Resource Program Center 

P.O. Box 25287 

Denver, Colorado 80225 

August 2004 

U.S. Department of the Interior 

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

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sending a request to the address on the back cover. 

Please cite this publication as: 

Thornberry-Ehrlich, T. 2004. Glacier National Park Geologic Resource Evaluation Report. Natural 

Resource Report NPS/NRPC/GRD/NRR—2004/001. National Park Service, Denver, Colorado. 

NPS D-450, August 2004 
 GLAC Geologic Resource Evaluation Report iii

Table of Contents 

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

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

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

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

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

Glacial Setting ............................................................................................................................................................4

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

Economic Resources..................................................................................................................................................9

Mining Issues..............................................................................................................................................................9

Avalanche Hazards ..................................................................................................................................................10

Wetlands ..................................................................................................................................................................10

Cave Resource Issues .............................................................................................................................................10

Seismicity .................................................................................................................................................................11

Slope Processes.......................................................................................................................................................11

Glacier Formation.....................................................................................................................................................12

Paleontologic Potential .............................................................................................................................................12

Faulting and Deformation Processes........................................................................................................................12

Glacial Retreat..........................................................................................................................................................13

Water Issues.............................................................................................................................................................13

Streamflow, Channel Morphology and Sediment Load.............................................................................................14

Wind Erosion and Deposition ...................................................................................................................................14

General Geology ......................................................................................................................................................14

Geologic Features and Processes............................................................................. 16

Glacial Features .......................................................................................................................................................16

Glacial Retreat..........................................................................................................................................................17

Glaciers ....................................................................................................................................................................18

Short-lived Glacial Features .....................................................................................................................................18

The Belt Supergroup ................................................................................................................................................18

Faults at Glacier .......................................................................................................................................................19

Akamina Syncline.....................................................................................................................................................20

Formation Properties.................................................................................................. 29

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

Geologic History.......................................................................................................... 33

References................................................................................................................... 44

Appendix A: Geologic Map Graphic .......................................................................... 48

Appendix B: Scoping Summary................................................................................. 49

Appendix C: Geoindicators Scoping Report ............................................................ 52

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

List of Figures 

Figure 1: Map of Montana with physiographic features surrounding Glacier National Park ...........................................6

Figure 2: Map of structural features in Glacier National Park area.................................................................................7

Figure 3: Map showing location of Glacier National Park in relation to Pinedale glacier and ice sheets........................8

Figure 4: Photo of three hanging valleys......................................................................................................................21

Figure 5: Diagrammatic view of a retreating glacier .....................................................................................................22

Figure 6: Map of Glacier National Park showing locations of the largest glaciers present today .................................23

Figure 7: The aerial extent of Sperry Glacier ...............................................................................................................24

Figure 8: Short-lived surface features on glaciers........................................................................................................24

Figure 9: Formation of stromatolites.............................................................................................................................25

Figure 10: Location of Glacier National Park relative to the entire Belt Terrane...........................................................26

Figure 11: Structural features east of Glacier National Park ........................................................................................27

Figure 12: Prominent structural features inside Glacier National Park.........................................................................28

Figure 13: Map of present day structural features superimposed on preexisting features ...........................................37

Figure 14: Depositional environment of the Prichard-Altyn Formation .........................................................................38

Figure 15: Conceptual depositional environment of the Ravalli Group.........................................................................38

Figure 16: Middle Belt Carbonate depositional facies ..................................................................................................39

Figure 17: Conceptual depositional environment of the Missoula Group .....................................................................40

Figure 18: Inferred Proterozoic structure of the Belt basin during Missoula Group deposition.....................................41

Figure 19: Subaqueous and subaerial phases of Purcell Lava ....................................................................................41

Figure 20: Deposition of the Kishenehn Formation ......................................................................................................42

Figure 21: Geologic Time Scale...................................................................................................................................43
 GLAC Geologic Resource Evaluation Report 1

Executive Summary 

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

numerous published and unpublished geologic maps of the area covering Glacier National 

Park in Montana. It contains information directed towards resource management and 

scientific research. National Park Service Geologic Resources Evaluation staff have 

assembled the digital geologic map that accompanies this report. 

The story of Glacier National Park is the story of geology 

and ice: the natural ice of snowfall and glaciers and the 

rocks that form the basis for the entire ecosystem. The 

experience of Glacier National Park begins with the 

geological processes that established the groundwork 

from which the present- day environments and scenery 

arise. Understanding the geologic resources can directly 

impact resource management decisions pertaining to the 

Park, future scientific research projects, interpretive 

needs, and economic resources associated with Glacier 

National Park. 

Geologic processes initiate complex responses that give 

rise to rock formations, mountains and valleys, waterfalls 

and lakes. The geology inspires wonder in visitors (some 

1,864,822 in 2002) to Glacier National Park, and emphasis 

of geologic resources should be encouraged so as to 

enhance the visitor’s experience. 

As the name suggests, Glacier National Park hosts some 

of the most spectacular glacial geomorphology on earth. 

The interplay of geology, water, ice, tectonic forces, and 

climate created this architectural elegance on the 

landscape at Glacier. It is not surprising then that some 

of the principal geologic issues and concerns pertain to 

protecting these features. Humans have modified the 

landscape both in and surrounding Glacier and 

consequently have modified its geologic system. This 

system is dynamic and capable of noticeable change 

within a human life span (less than a century). 

The following features, issues, and processes were 

identified as having the most geological importance and 

the highest level of management significance to the park: 

• Slope failures and processes. Alpine environments are 

especially susceptible to slumping and landslide 

problems due to the lack of stabilizing plant growth 

combined with the substantial seasonal runoff and 

relatively frequent occurrence of intense seasonal 

rainstorms. This runoff can dramatically alter the 

landscape, creating new hazard areas in the process. 

Road and trail construction also impacts the stability 

of a slope. Mudstone- rich units are typically found in 

outcrop as slopes which are prone to fail when water 

saturated. In addition to this hazardous situation, the 

more resistant units in the park are exposed as cliffs. 

This creates a situation exposing large blocks of 

jointed and faulted sandstone and limestone to the 

force of gravity. Rockfall and slope failure is a potential 

hazard almost everywhere along the roads and trails of 

Glacier National Park. 

• Glacial retreat. The park was created to preserve and 

protect some of the most spectacular glacial features in 

the world, including active glaciers. The glaciers at 

Glacier National Park have been retreating at a rapid 

rate, almost continuously since the mid 1800’s – and in 

some models will be gone entirely by 2015. This retreat 

is intimately linked with regional to global climatic 

changes. 

• Streamflow and channel morphology. In the climate of 

northwestern Montana, seasonal runoff and intense, 

short duration, seasonal rainstorms and subsequent 

flooding may impact channel morphology. These 

seasonal events also result in changes in the load and 

deposition of sediment in the valleys and along 

riverways. These changes affect aquatic and riparian 

ecosystems. Sediment loading can result in changes to 

channel morphology and overbank flooding 

frequency. 

• Economic resources. Intimately tied with the story of 

Glacier is the record of man’s quest to extract useful 

materials from the earth. Rocks in and near Glacier 

contain vast amounts of oil and gas as well as copper 

and other metallic ore deposits. Many of the 

Cretaceous age units underlying the park contain large 

amounts of coal. Management consideration must be 

given to these potential resources and their effect on 

the preservation of the pristine park environment. 

• Avalanche threat. Glacier receives vast amounts of 

snowfall each winter. This, when combined with steep 

slopes and southern exposures creates severe snow 

avalanche hazards within and around the park. For 

this reason, monitoring climate and snow conditions is 

essential for predicting avalanche dangers in high risk 

areas, especially along the southern boundary along 

US Highway 2 and Going to the Sun Road. Avalanches 

or ice rafts from glaciers can form temporary dams 

across waterways, causing a severe flood hazard. These 

processes leave a substantial trace on the landscape. 

The park staff should be prepared to adjust 

accessibility when necessary to protect resources and 

public safety. 
 NPS Geologic Resources Division 2 

Other geologic parameters and issues such as the 

paleontological potential of the area, wind erosion and 

deposition, gravel and sand deposits, the process of 

glacier formation, wetlands, mining problems, seismicity, 

water issues, faulting and deformation processes, and 

cave resources, were also identified as critical 

management issues for Glacier National Park. These are 

listed in detail along with recommendations for 

inventories, monitoring, and research on pages 15- 20. 

However, beyond just resource issues and concerns, the 

rocks of Glacier record the ancient beginnings of life on 

earth. The Precambrian Belt Supergroup strata range in 

age from about 1,325 million years ago (m.y.) to about 900 

m.y. The Belt Supergroup was thrust over Cretaceous age 

shales in the Glacier Park area. The Precambrian strata 

are mostly reddish- brown and greenish- gray argillite 

and siltite with some quartzite and carbonate (Prichard, 

Grinnell and Snowslip Formations). They were 

deposited in near and far shore environments. The 

Empire Formation is a transitional unit as much as 1,170 ft 

(375 m) thick between the under lying Grinnell 

Formation and overlying Helena Formation. The Altyn, 

Helena, and Shepard Formations compose the Belt 

carbonate units. They reflect deeper water depositional 

settings with a carbonate saturated water chemistry. 

Stromatolites in these carbonate units record the only 

traces of Proterozoic life in the Belt basin. These unique 

features are formed by blue- green algae, primarily 

responsible for the oxygen rich atmosphere we breathe 

today. 

Because of the nature of the landscape, several potential 

geological issues need to be considered with regard to 

land- use planning and visitor use in the Park. Along with 

a detailed geologic map and road log, a guidebook that 

would tie Glacier National Park to other Parks in the 

Pacific Northwest would enhance a visitor’s appreciation 

of the geologic history and dynamic processes that not 

only created Glacier but also created the spectacular 

landscape of the entire region. Strategically placed 

wayside exhibits can help explain the geology to the 

visitor. 
 GLAC Geologic Resource Evaluation Report 3

Introduction 

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

Park Service Geologic Resources Evaluation program. 

Purpose of the Geologic Resources Evaluation Program 

Geologic features and processes serve as the foundation 

of park ecosystems and an understanding of geologic 

resources yields important information needed for park 

decision making. The National Park Service Natural 

Resource Challenge, an action plan to advance the 

management and protection of park resources, has 

focused efforts to inventory the natural resources of 

parks. Ultimately, the inventory and monitoring of 

natural resources will become integral parts of park 

planning, operation and maintenance, visitor protection, 

and interpretation. The geologic component is carried 

out by the Geologic Resource Evaluation (GRE) Program 

administered by the NPS Geologic Resource Division. 

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

identified 274 “Natural Area” parks with a digital 

geologic map, a geologic resource evaluation report, and 

a geologic bibliography. Each product is a tool to support 

the stewardship of park resources and is designed to be 

user friendly to non- geoscientists. 

The GRE teams hold scoping meetings at parks to review 

available data on the geology of a particular park and to 

discuss the specific geologic issues in the park. Park staff 

are afforded the opportunity to meet with the experts on 

the geology of their park. Scoping meetings are usually 

held at each park to expedite the process although some 

scoping meetings are multipark meetings for an entire 

Vital Signs Monitoring Network. 

Bedrock and surficial geologic maps and information 

provide the foundation for studies of groundwater, 

geomorphology, soils, and environmental hazards. 

Geologic maps describe the underlying physical habitat 

of many natural systems and are an integral component 

of the physical inventories stipulated by the National 

Park Service (NPS) in its Natural Resources Inventory 

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

Strategic Plan. The NPS Geologic Resources Evaluation 

(GRE) is a cooperative implementation of a systematic, 

comprehensive inventory of the geologic resources in 

National Park System units by the Geologic Resources 

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

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

Geological Survey, and state geological surveys. 

For additional information regarding the content of this 

report please refer to the Geologic Resources Division of 

the National Park Service, located in Denver, Colorado 

with up- to- date contact information at the following 

website: 

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

Geologic Setting 

In December 1907, Montana Senator Thomas Carter first 

introduced legislation to authorize the land in northwest 

Montana as a national park over some objections of local 

residents. Fortunately for future generations, Montana 

Congressman Charles Pray, noted environmentalist 

George Bird Grinnell and James J. Hill of the Great 

Northern Railroad, fought to pass the legislation 

designating the park which was signed by President 

Howard Taft on May 11, 1910. By 1910, the controversy 

regarding potential mineral wealth had diminished in the 

face of hard economic reality. The rugged mountain 

wilderness with breathtaking scenery, rich in geologic 

wonders, was claimed by the federal government as a 

protected national park. 

Glacier National Park encompasses about 1545 square 

miles (4100 square kilometers) of rugged, glaciated, 

mountainous terrain in northwestern Montana. It is 

located within the northeastern section of Belt Terrane, 

covering parts of Montana, Idaho, Washington, and 

southern Canada, and contains incredible exposures of 

Precambrian age Belt Supergroup sedimentary rocks, 

which in Tertiary time were displaced eastward onto 

Cretaceous age rocks by the Lewis thrust fault. These 

remarkable ancient rocks are relatively undeformed and 

unchanged by the forces of pressure and heat and remain 

among the finest examples of Precambrian sedimentary 

rocks in the world. They record an ancient Belt basin 

(sea) environment, opening and closing intermittently 

over many millions of years. The rocks record a 

quiescent northwestern margin to the North American 

craton similar to the modern day Atlantic Coast. 

Paleozoic, Mesozoic, and Cenozoic rocks, deposited on 

top of the Belt rocks are missing at Glacier National Park. 

They were eroded long ago leaving the rocks we see in 

the present jagged peaks. This resulted in a unique as 

well as enigmatic geological setting. The Cretaceous 

rocks beneath the Lewis thrust sheet record the 

Cretaceous Inland Seaway, a vast inland sea that once 

stretched from the Arctic Ocean to the Caribbean Sea. 

This environment was rich in prehistoric flora and fauna. 

The park is defined by sweeping U- shaped, glaciated 

valleys bounded by dramatic, shear rock faces topped by 

pinnacles of layered rock. The many streams and lakes, 

following the paths of previous glaciers descend outward 

from the continental divide, which runs up the middle of 

the Park. Over 700 miles of trails traverse the park giving 

backcountry access to thousands of visitors each year. 

The Going to the Sun Road crosses the park with 

stretches clinging to the steep walls of the glacial valleys. 
 NPS Geologic Resources Division 4 

Completed in 1932, the road is an engineering marvel and 

is listed as a National Historic Landmark. 

Glacier National Park is in a southwesterly trending, 

structurally low area that is bounded on the north and 

south by southwest- trending structures or arches. The 

low, bowl- shaped depression of the basement rocks that 

influenced the present setting of the Glacier Park area 

was very likely established by the end of Cretaceous time, 

and it probably controlled, at least in part, the present 

northwest trending structural pattern in the area, a 

pattern resulting from the Laramide (early Tertiary) 

orogeny (Mudge 1977). 

The Park is dominated by two linear mountain ranges 

trending northwest- southeast. On the west side of the 

Park, the Livingstone Range runs about 35 km (22 miles) 

from the Park boundary to Lake McDonald. To the east, 

the Lewis Range extends the full length of the Park, a 

distance of about 100 km (61 miles) from the 

International Park boundary on the north to Marias Pass 

on the south. The Continental Divide runs along the 

crest of the Lewis Range from Marias Pass to about 16 km 

(10 miles) south of the U.S. – Canada border; then it 

swings west to the crest of the Livingstone Range into 

Canada (Elias 1985). 

Glacier National Park contains the eastern front of the 

Rocky Mountains of the United States (figure 1). It is also 

part of a series of northwest trending mountain ranges in 

Western Montana including the Whitefish Range 

(immediately west), the Flathead, Swan and Mission 

Ranges (to the southwest). The Sweetgrass Hills (part of 

the Sweetgrass Arch) bound the Park on the east. The 

Purcell Anticlorium, to the west of the Whitefish Range, 

contains the Purcell Mountains and the Salish 

Mountains in a region of broad folds that forms a large, 

elongate dome structure in far western Montana and 

eastern Idaho. The Bitterroot Mountains, which form 

the border between Montana and Idaho were mistaken 

by the Lewis and Clark survey team in 1805 as the 

continental divide. They followed the Bitterroots instead 

of the Anaconda Range north into Montana when 

surveying the boundary giving Idaho its “panhandle” and 

Montana some spectacular scenery. 

Glacier National Park is considered part of the 

Cordilleran fold and thrust belt of the United States; 

continuous with that known in the southern Canadian 

Cordillera (McGimsey 1982). Price (1981) has interpreted 

the region to be a portion of the complex structures that 

resulted from intermittent collisional plate interactions 

beginning nearly 200 m.y. ago. Prominent regional 

structural features include: 1) the Lewis thrust fault 

system, 2) the disturbed Belt, a zone of closely spaced 

imbricate thrust faults to the east, 3) the Rocky Mountain 

Trench, a zone of closely spaced normal faults to the 

west, and 4) the Lewis and Clark line to the south, a 

major intraplate tectonic boundary in the region (figure 

2). Deformation in the Cordilleran orogen was initiated 

during the late Jurassic and is believed to have 

terminated by late Eocene time (McGimsey 1982). This 

fold and thrust belt, however, has been undergoing 

extension since late Tertiary time along a series of major 

normal faults. 

Glacial Setting 

The name Glacier National Park is somewhat of a 

misnomer. Many visitors come to the park expecting to 

see enormous glaciers similar to those in Alaska. While 

those undoubtedly existed at one time in Glacier as 

evidenced by the U- shaped valleys, hanging valleys, 

cirques and other glacial features, today the warmer, 

drier climate could not support such ice masses. There 

are glaciers in the park still viewable by the public, but 

most have retreated back to their source cirques. What 

does remain of the past ice ages are the sculpted rocks 

and remnants left behind when these massive glaciers 

melted some 10,000 years ago. 

Glaciers flowed ever so slowly down drainages that now 

contain narrow lakes. The numerous mountain valleys 

that wind their way between the high peaks are Ushaped, the typical product of glacial sculpting. The Park 

has been the setting for at least ten periods of widespread 

glaciation. It is difficult to determine just when the first 

advance took place, as evidence of early advances is 

often destroyed by later advances, but it may have been 

very early in the Pleistocene. 

The Wisconsin Glaciation (the most recent of the 4 

major Pleistocene Glaciations, from oldest to youngest: 

Nebraskan, Kansan, Illinoisan, and Wisconsin), is called 

the Pinedale Glaciation in the Rocky Mountain region 

(after terminal moraines near the town of Pinedale, 

Wyoming). The Pinedale Glaciation began after the last 

interglaciation, perhaps 110,000 years before present 

(B.P.), and included at least two major ice advances and 

retreats. Two ice sheets covered more than 16 million km2

(6 million square miles) of North America, stretching 

from coast to coast. Glacier National Park was uniquely 

situated, hemmed in by the two great ice sheets (Elias 

1996) (figure 3). 

At the height of the Pinedale Glaciation, about 20,000 

years ago, only the highest ridges and peaks in the Park 

were free of ice. These ice- free regions are called 

nunataks; today these appear as horns and arêtes. 

Mountain glaciers that formed on the western slope of 

the Continental Divide in the Livingstone Range flowed 

down the valley of the North Fork of the Flathead River. 

These glaciers joined with ice coming from the eastern 

slope of the Whitefish Range to the west, and the 

combined glaciers flowed south, overriding the lower 

Apgar Mountains, near West Glacier, and contributing 

ice to the Flathead Lobe of the much larger Cordilleran 

Ice Sheet. The Flathead Lobe gouged out a deep 

depression, and the terminal moraine left by this glacial 

lobe dammed the Flathead River about 20,000 years 

before present (B.P.), creating present day Flathead Lake 

(Elias 1996; Karlstrom 2000). 
 GLAC Geologic Resource Evaluation Report 5

Glaciers that flowed from the western side of the Lewis 

Range south of Lake McDonald merged with ice from 

the southeastern flank of the Flathead Range to the 

south. This ice flow, combined with other mountain 

glaciers southeast of the Park, formed a large body of ice 

around the southwestern corner of the Park. This body 

pushed up and over the low divide at Marias Pass and 

ended up becoming part of the large piedmont glacier 

called Two Medicine Glacier. 

This glacier was also fed by ice flowing from the southern 

end of the east slope of the Lewis Range. Two Medicine 

Glacier flowed out over the eastern plains for several 

kilometers, nearly intersecting with the massive 

continental ice sheet, or Laurentide Glacier, coming 

from the east. Farther north along the eastern slope of 

the Lewis range, mountain glaciers flowed out onto the 

plains to form the Cut Bank and St. Mary’s glaciers. Ice 

from the northwestern flanks of the Lewis Range and the 

northeastern flank of the Livingstone Range flowed 

north in to Canada (Elias 1996; Osborn and Gerloff 1997; 

Karlstrom 2000). 

During the Pinedale Glaciation, active volcanoes in the 

Cascade Range in Washington and Oregon erupted and 

deposited ash layers in the Glacier Park Region. These 

ash layers can be accurately identified, dated, and 

correlated in the large moraines left from Pinedale 

Glaciers. They provide useful dates about the timing of 

glacial recession in the area. Pinedale deglaciation was 

fairly rapid and by 11,200 years B.P. the ice had retreated 

to local mountain valleys in the Park, and by 11,300 and 

10,000 14C years B.P. (using radiocarbon dates, tree- ring 

data, macrofossils, and the presence of the Mazama, 

Glacier Peak G and St. Helens J volcanic ash beds) it had 

withdrawn to the same high- mountain cirques and 

shaded niches where small glaciers persist today (Carrara 

and Wilcox 1984; Elias 1996; Osborn and Gerloff 1997). 

The present day ice is probably not the remnants of 

Pinedale Glaciation. About 6,000 years ago all glacial ice 

probably disappeared from the mountains. After this 

there was a warm, dry climatic period during which it is 

probable that no glaciers were present (Carrara 1986). 

Then about 4,000 years ago the climate became wetter 

and cooler again, and small glaciers present today were 

formed (Dyson 1966). 
Figure 1: Map of Montana with physiographic features surrounding Glacier National Park. Modified version of map from PerryCastañeda Library Map Collection. 

 NPS Geologic Resources Division 6 
Figure 2: Map of structural features in Glacier National Park area, modified from McGimsey 1982. 

 GLAC Geologic Resource Evaluation Report 7
Figure 3: Map showing location of Glacier National Park in relation to glacier and ice sheets present during the Pinedale Glaciation’s 

maximum extent. Modified from Carrara 1986. 

 NPS Geologic Resources Division 8 
 GLAC Geologic Resource Evaluation Report 9

Geologic Issues 

A Geologic Resources Evaluation (GRE) workshop and Geoindicators scoping meeting 

were held at Glacier National Park on August 20- 22, 2002, to discuss the geologic 

resources, and to assess resource management issues and needs. The following pages 

synthesize the results of these meetings to address economic resources, potential 

geological issues, future scientific research projects, and interpretive needs for Glacier 

National Park. 

Economic Resources 

In the Glacier National Park area, many of the 

Cretaceous age rocks contain beds of coal. Coal is also 

present in the Tertiary age Kishenehn Formation. These 

beds are thin and discontinuous making economic 

extraction difficult. See Unit Properties and Limitations 

section for more information about specific units. 

The structural features present at Glacier National Park 

including faults and folds are natural fossil fuel traps. 

Exploration for oil and gas in the area began as early as 

1892. This exploration led to the formal report of the 

Canadian Geological Survey on the subject of the 

numerous oil seeps in the region. While the bulk of 

exploration for oil and gas takes place in Canada, the 

region has been continuously scrutinized for its potential 

fossil fuel abundance. Before the formation of the park, 

drilling along the western slope in the North Fork of the 

Flathead River Valley, near oil seeps, failed to achieve 

significant production in 1901 (Boberg 1984). The first oil 

well drilled in what is now the park was located at the 

east end of Lake Kintla, begun in October 1901. 

The primary structure in the Park area, the Lewis thrust 

system, is largely responsible for the capture of oil and 

gas. The thrust sheet covers Paleozoic, Mesozoic and 

Cenozoic age rocks, rich in organic materials. Upon 

burial, fossil fuels matured and flowed upwards through 

cracks and joints to produce the telltale seeps in the area. 

The oil in the seeps is high API gravity (low specific 

gravity), generally light in color, very volatile with little 

residue. The seeps are often coincident with water 

springs and are ephemeral as opposed to perennial 

(Boberg 1984). Seeps are located in the Park area at 

Kishenehn Creek, Sage Creek Headwaters, Bowman 

Lake, Kintla Lake, Christensen Ranch, and Mount Hefty 

among others. 

Pleistocene glaciation may also have played a role in the 

formation of some oil and gas interest in the Glacier 

National Park area. Organic debris trapped in glacial 

sediments such as till can be sufficiently sealed so that 

when it decays, it produces methane gas that can be 

trapped in place until released by drilling or erosion. This 

release can be mistaken for an oil seep. 

The lakes and marshes characteristic of the glacial 

landscape in the Park can also lead to organic matter 

decay and release of methane gas (swamp gas) from 

sediments underwater (Boberg 1984). 

The Waterton Lakes area and areas of British Columbia 

north of Glacier National Park produce oil and gas from 

the Lewis thrust sheet at the present time. There has 

been continual interest in the Glacier National Park area 

for pervasive exploration and drilling. Balancing the 

pristine nature of the Park and economic interests is 

essential to Park management. 

While not permissible within the park, development of 

coal, oil, and gas surrounding the Glacier area pose a 

threat to the park’s viewshed and ecosystem. The influx 

of drill rigs and extraction equipment necessary for oil 

and gas production creates new road construction, water 

pollution, noise pollution and a localized population 

increase. 

Inventory, Monitoring, and/or Research Needs 

• Park staff should remain aware of the potential 

encroachment of oil and gas exploration in the area of 

the park. 

• Acquire plugging records of oil and gas wells 

potentially connected to park groundwater systems. 

Mining Issues 

The initial interest in the Glacier National Park area was 

fueled by potential mineral wealth. After the Civil War, 

the region, like much of the American West, embodied 

the ideals of untamed capitalism, and was seen as a sea of 

endless possibilities for settlement, mining, and later, 

fossil fuel extraction. The various dikes, sills and other 

igneous intrusions led to the formation of the ore 

deposits in the Belt Supergroup rocks. 

When an early explorer, Dutch Lui’s, illegal prospecting 

efforts indicated the presence of copper ore east of the 

continental divide, word spread and soon other squatters 

were disregarding the Blackfeet Reservation laws. The 

Blackfeet, desperate and pressured, sold the “ceded 

strip” (area of Glacier Park east of the continental divide) 

for $1.5 million in 1896; an Act of Congress officially 

changed the land on April 15, 1898. 
 NPS Geologic Resources Division 10 

The area of the ceded strip was nearly half the area of the 

present day Park. Hundreds of anxious miners staked 

claims hoping to strike it rich, perhaps finding gold or 

silver as well. By 1902, the ceded strip, so alluring to 

impatient prospectors, was largely abandoned because 

no economically viable deposits of ore were uncovered. 

The prospectors all moved to the next “hill” in search of 

instant riches and the ceded strip was largely abandoned. 

Metallic mineral deposits were rare and few discoveries 

were made. Although copper is often associated with 

gold and silver, no economic deposits of base or precious 

metals were found in Glacier National Park. Mining in 

the area was abandoned prior to 1910. All that remains in 

the park are abandoned mine openings and deteriorating 

equipment. 

Abandoned mines pose a serious potential threat to the 

ecosystem from acid mine drainage and heavy metal 

concentrations in both surface and groundwater. Heavy 

metals may also contaminate the surrounding soil, 

adversely impacting plant and animal life. 

Inventory, Monitoring, and/or Research Needs 

• Periodic water (surface and groundwater) and soil 

sampling and testing should be conducted to detect 

heavy metals in those resources. Drinking water is 

especially important to monitor. 

• Research needs include a thorough investigation of ore 

bearing beds throughout the park including 

descriptions, ore content tests, and locations, i.e. 

where the beds crop out and are accessible to the 

public, flora and fauna. 

• Complete inventory of the ore content in the recent 

unconsolidated deposits and soils as well as the ore 

bearing stratigraphic units. 

Avalanche Hazards 

Glacier receives substantial snowfall each winter. This 

combined with the extreme slopes and exposures creates 

severe snow avalanche hazards within and around the 

park. Monitoring climate and snow conditions allows for 

some predictability of avalanche dangers in high risk 

areas such as the southern boundary along US Highway 2 

and Going to the Sun Road. 

Avalanches or ice rafts from glaciers can form temporary 

dams across waterways. One dramatic example of this 

was the damming of the Middle Fork of the Flathead 

River by an avalanche, destroying a bridge, in 1979. When 

the dam inevitably melted, the rush of water and debris 

destroyed many structures along U.S. Highway 2, and it 

created a long detour for motorists and a large mess for 

clean- up crews and residents below the slide. During the 

winter of 2002- 2003, an avalanche destroyed some of the 

railroad and blocked the highway along the Park’s 

southern boundary. 

These processes leave a large mark on the landscape and 

the Park should be prepared to adjust accessibility when 

necessary to protect the resources and public safety. 

Inventory, Monitoring, and/or Research Needs 

• Perform an exhaustive mapping study of where 

specific snow accumulation areas are located on the 

slopes above Glacier’s valleys to allow for more precise 

hazard assessment. 

• Using repeat aerial photography to document the 

change in snow avalanche paths over time and 

document the effects of slope processes can predict 

hazard areas in the park. 

• Update surficial geologic map including snow 

avalanche paths, landslide areas, and lake deposits. 

• Snow avalanche studies including the frequency, 

cycles, and locations of avalanche sites are possible 

using historic records, satellite imagery, tree rings. 

From this information, comparing east and west side 

(of continental divide) cycles of snow avalanches 

would give an overall view of the climatic differences 

in the park. 

• Use climate information and topographic information 

in a GIS to map areas unsuitable for recreational 

development due to avalanche danger. 

Wetlands 

The dynamic nature of wetland environments makes 

them an indicator of the overall status of the ecosystem. 

Many sites have yet to be identified. The first step toward 

an inventory would be to validate the classification of the 

Fish and Wildlife Service and refine is delineation 

according to their guidelines. Once sites are identified 

and compared with past photographs and records, 

monitoring trends becomes possible. Parameters could 

include water chemistry, sediment influx and vascular 

plants. 

Inventory, Monitoring, and/or Research Needs 

• Study the effects of fire on wetlands and slope stability. 

Cave Resource Issues 

Several units including the Helena Formation and the 

Snowslip Formation contain enough carbonate layers to 

support cave systems. The Park does not have a current 

inventory of caves or their contents. 

Inventory, Monitoring, and/or Research Needs 

Conduct a survey which would consist of identifying 

cave locations. The project will include the cartographic 

survey, inventory, and legal land description of know 

cave resources. 

Conduct the cave inventory project of the park’s known 

cave systems by developing and implementing an action 

plan for the inventory of all known caves. 
 GLAC Geologic Resource Evaluation Report 11

This project will include mapping and assessment of the 

natural and cultural resources as follows: 

Priority 1: Conduct cartographic surveys of all known 

caves within +/- 2% error of closure. Data should be 

delivered on computer disk, compatible with a 

Geographic Information System, and as finished plan 

and profile Class 1 maps. Cave locations will be recorded 

on aerial photographs of each park and on USGS 

topographic maps (UTMs will be required for each cave 

entrance marked on the maps). Brass survey markers at 

least one inch in diameter will be obtained for marking 

cave entrances and tying into surface and cave surveys. 

Priority 2: In conjunction with the cartographic survey 

base line resource inventories will be conducted. Initial 

data collection will include the following information: 

geology, mineralogy, archeology (including all cultural 

associations), paleontology, hydrology, and biology 

(flora and fauna). This data collection process will be 

accomplished through contracts, MOUs, and/or park 

personnel. 

Seismicity 

Earthquakes are common, but mostly too small to feel in 

the northwest Montana area. Tremors in conjunction 

with wet, unstable slopes could pose a serious threat to 

the parks resources, roads and visitors. 

Inventory, Monitoring, and/or Research Needs 

• Perform a comprehensive study of the faulting and 

seismic processes active at Glacier National Park, 

taking into account rock formations, slope aspects, 

location and likelihood of instability. 

• The cliffs above the Going to the Sun Road are prone 

to slumping and sliding (see Formation Properties 

table). The slopes of this area would likely fail in a 

moderate to large seismic event. Care must be taken 

when planning trails and other visitor access along 

steep walls beneath obvious rockfall prone areas. 

• Monitor seismic activity in the Glacier area by 

cooperating with local agencies including the USGS 

and Montana Geological Survey. 

• Perform exhaustive study of seismic/active faults in 

close proximity to the Glacier area including the 

mapping of small scale faults and shear fractures. 

Slope Processes 

The topographic relief in Glacier is extreme. In areas 

such as Going to the Sun Road and Many Glacier Road, 

the likelihood of landslides increases with precipitation 

and undercutting. Using a topographic map and a 

geologic map in conjunction with rainfall information 

could provide some warning for areas especially at risk. 

The intense erosion of the steep slopes is responsible for 

the stunning vistas at Glacier National Park. However, 

these erosional processes are also the cause of the most 

important geological resource management issue: mass 

wasting and rockfalls. 

The walls of many of the broad valleys at Glacier have 

extreme slopes. This renders them highly dangerous 

because of the likelihood of rock falls, landslides, slumps, 

and slope creep. This issue is a major concern in the 

weaker rock units such as shales and siltstones. Stronger 

rock units such as the Helena and Grinnell Formations 

are highly fractured making them a hazard in rock fall 

situations. 

Similarly, slumps and other forms of slope failure are 

common for units that are not necessarily associated 

with cliffs. Unconsolidated alluvium deposits for 

instance, are especially vulnerable to failure when 

exposed on a slope. The incredible large volume of 

runoff can scour alpine slopes lacking stabilizing plant 

and tree roots. The rock and soil, suddenly saturated 

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

mudslide, or flow. 

Many trails in the park trail lead visitors through 

spectacular alpine and forest scenery, however, these 

trails are at extreme risk for rockfall and landslides. In 

less visited areas of the park slope processes are also 

creating an impact. 

Inventory, Monitoring, and/or Research Needs 

• Perform a comprehensive study of the 

erosion/weathering processes active at Glacier 

National Park, taking into account the different rock 

formations versus slope aspects, location and 

likelihood of instability. 

• Create a rockfall susceptibility map using rock unit 

versus slope aspect in a GIS; use the map in 

determining future developments and current 

resource management including trails, buildings, and 

recreational use areas. 

• Inventory and monitor debris flow potential near 

picnic areas, relate to slope and loose rock deposits. 

• Inventory runoff flood susceptible areas, relate to 

climate and confluence areas 

• Perform trail stability studies and determine which 

trails are most at risk and in need of further 

stabilization. 

• Siting facilities is also a major issue because of the 

fractures and potential for sloughing; these areas 

should be monitored for growth and potential danger. 

• Further research the causes of landsliding and 

slumping to help predict future events. 
 NPS Geologic Resources Division 12 

• The potential for landslides and rockfalls exists along 

all roads and trails at Glacier National Park. The risk of 

such occurrences is greatest during the spring runoff 

season when high levels of snowmelt saturate the thin 

alpine surficial deposits. 

Glacier Formation 

Glaciers form when the average snowfall exceeds the rate 

of average melting. When this happens, snow begins to 

accumulate from year to year in what is called an 

accumulation zone. The snow turns to ice, and as it 

thickens, the ice undergoes plastic deformation (a 

permanent change in shape of a solid that does not 

involve failure by rupture) and begins to creep 

downslope under the force of gravity. No other erosional 

process on earth is as effective as glacial erosion. As 

glaciers move downslope, they pluck underlying rocks 

from the hillside and carry them along in the glacial ice. 

The boulders act as abrasives to gouge, scour, and polish 

the floor and walls of the valley down which the glacier 

flows. 

During the mid- 19th century, more than 150 glaciers in 

Glacier National Park advanced to their furthest extent 

since the Pinedale glacial event. Glacier National Park is 

the only park in the conterminous U.S. Rocky Mountain 

region with a climate suitable for maintaining substantial 

glaciers since the end of the Pinedale glacial maximum 

some 10,000 years ago. This climate exists there for two 

reasons. One is that the Park is situated far enough north 

and its mountains are high enough to keep relatively cool 

in the short summers. The other reason is that the 

mountains in the Park are high enough to capture 

significant precipitation from moist Pacific air moving 

inland. 

The impressive glaciers that existed in northwestern 

Montana at the turn of the twentieth century, along with 

the incredible mountain scenery and wildlife, led to the 

creation of the Park. When the park was established in 

1910, the glaciers were already retreating from their 

interglacial maximum around 1850, when they were 

larger than they had been in the last 10,000 years (Elias 

1996). Since the Little Ice Age (16th – 18th centuries), many 

of the remaining glaciers have shrunk to the point of 

becoming snowfields, no longer capable of downslope 

movement. 

Inventory, Monitoring, and/or Research Needs 

• Monitor and inventory human signatures in the park 

on glaciers. 

• Study the role of enlarging fractures around glaciers 

due to freeze- thaw cycles. 

• Study how different lithologies respond to glacial 

movement. 

• To comprehensively study and monitor the 

atmospheric conditions and snow accumulation in the 

park 

Paleontologic Potential 

The alpine landscape at Glacier contains more than just a 

collection of glacial features, it contains a record of 

prolific ancient life. Fossils at the park record the first 

forms of life and include several types of Precambrian 

age algae (stromatolites) and later Cretaceous oysters, 

brachiopods and dinosaurs. These preserved specimens 

should be protected and catalogued for scientific study, 

future generations, and increased visitor appreciation of 

the entire park. 

Inventory, Monitoring, and/or Research Needs 

• Study the Cretaceous rocks to determine if dinosaur 

and other fossils are present in the backcountry. 

• Perform a comprehensive study of the paleontologic 

resources at Glacier National Park. 

• Compile an inventory of all paleontologic specimens 

present in the park. 

• Ongoing discussion of the lifeforms present during the 

Precambrian age demands more detailed, microscopic 

study of the preserved sedimentary Belt rocks of 

Glacier. 

• Attempt to determine the locations of paleontologic 

specimens removed from the park as part of private 

collections to obtain an accurate inventory. 

• Draw visitor attention to the fossil resources at Glacier 

with graphics, brochures and exhibits. 

• The susceptibility to erosion difference between 

Conophyton and Baicalia stromatolites 

Faulting and Deformation Processes 

The rock units present at Glacier have undergone 

multiple phases of deformation resulting in folds, faults, 

joints and other fractures. These features compromise 

the strength of any rock unit. These weaknesses have 

many effects on the features present at Glacier. For 

instance, a fault or fracture can serve to focus surface 

runoff, eventually widening into a stream gulley such as 

Sunrift Gorge. 

Deformation is still occurring at Glacier. Rocks are 

responding to pressures within the earth and recent 

small scale fractures and joints attest to this. 

Understanding the nature of these features allows 

predictions of where weathering and erosion are likely to 

be concentrated making this knowledge indispensable to 

resource management. 
 GLAC Geologic Resource Evaluation Report 13

Inventory, Monitoring, and/or Research Needs 

• Study the role of jointing versus faulting (including 

strike- slip, normal, and thrust faulting). 

• Determine extent of Cretaceous deformation below 

the Lewis thrust to the south and east. 

• Conduct an inventory of any recent fault scarps in the 

area. These are commonly present in Quaternary 

surficial deposits. 

Glacial Retreat 

Glacial retreat is of major interest to resource managers 

at Glacier as well as to climate researchers worldwide. 

The glacial response to climate change is immediate and 

striking. The overall trend of glacial retreat at Glacier 

National Park indicates the local climate is getting 

warmer, possibly evidence of a global greenhouse effect. 

From six glaciers mapped from 1993 aerial photos, and 

two mapped through 1979, retreat from ca. 1850 maxima 

ranged from 818- 1440 m and averaged 1244 m. Overall 

retreat rates varied between 6- 17 m/yr. Those glaciers 

were reduced in area by 62- 80%, for an average 

shrinkage to 27% of the estimated area in 1850. Climate 

models suggest that all the glaciers in the park will be 

gone by 2025. 

Inventory, Monitoring, and/or Research Needs 

• Research of how observed glacier changes might affect 

streams and surface characteristics across a mountain 

landscape is of interest to ecosystem modeling and 

climate change research. Further work in the Glacier 

National Park area is needed to complete regional 

assessment of glacial recession, and address 

climatological and ecological implications. 

• Study rates of edge retreat and migration, erosion, 

retreat of leading edge, rates of downcutting of streams 

on the glacier’s surface, and accumulation of fill 

(glacial till) at bottom. 

Water Issues 

Water is ubiquitous in the park and preserving its pristine 

state is crucial. The potential for pollution from human 

waste facilities, campgrounds, watercraft, and vehicular 

use requires intense regulation of the human impact in 

the Park. Groundwater, either from precipitation or 

snow melt moves quickly through the fractured bedrock 

and down steep hydraulic gradients in the Park. Because 

of the dynamic nature of the interaction between water 

and geologic processes at Glacier National Park the role 

of hydrogeology must be taken into consideration when 

making management decisions. 

The interaction between water and geology is especially 

obvious in a mountainous environment like Glacier 

which receives significant snowfall each year. The glacial 

features described above lend a unique aspect into the 

situation. The moraines left by glaciers commonly act as 

dams to the drainages in front of the glaciers. These can 

be found in any scale in Glacier from Lake McDonald, to 

a small alpine tarn (lake). If these dams should fail, the 

potential flash flood would have a tremendous impact on 

the valley below the lake. 

Water continues to play a critical role in sculpting the 

present landscape of Glacier National Park. During 

intense seasonal thunderstorms, rain acts like a 

sledgehammer on unprotected soil, knocking apart 

individual soil particles and washing unconsolidated 

sediment into the valleys. The steep slopes of Glacier’s 

valley walls are susceptible to intense erosion and rock 

fall during these storms. 

Fire activity only increases the likelihood of rock fall and 

landslides by removing the stabilizing plant material from 

the slopes. Water freezing and thawing also plays a large 

role in changing the landscape. The expansion upon 

freezing pries rocks apart, crack by crack. 

The thin, poorly sorted, glacially- derived alpine soils of 

glacier are susceptible to slumping and sliding especially 

when water- saturated. This can be a hazardous situation 

for roadways and trails which are situated on or near 

steep slopes and planners must be prepared to predict 

when the potential hazard is high and adjust accessibility 

to those areas accordingly. Slide Lake for instance, 

formed when a recent landslide blocked Sherburne 

Creek, diverting forever the trail that once was along the 

lakeshore. 

The North Fork Valley is largely underlain by the 

Tertiary age Kishenehn Formation. This formation 

contains clays derived from volcanic sediments including 

bentonite. Bentonite is a clay mineral which greatly 

expands when wet causing the rocks around it to crack 

and move. This type of shrink- and- swell clay poses an 

obstacle to road and trail builders. The presence of 

bentonite and its hydrogeologic properties in the North 

Fork Valley should be noted in the planning of future 

roads, facilities, and/or trails. 

Inventory, Monitoring, and/or Research Needs 

• Determine the nature of the park’s watershed by 

compiling baseline watershed, and surface to 

subsurface hydrogeologic data. 

• Monitor water quality on a multiple sample location 

basis within the park, drinking water sources are 

especially important. . 

• Conduct a thorough inventory of lakes in the park. 

• Create a “lake ice model” to determine climate change 

patterns and help the management of wildlife such as 

migrating waterfowl. 

• Install further wells for testing and drinking water 

access. 
 NPS Geologic Resources Division 14 

• The impacts of nearby mining are unknown (see above 

mining issues discussion) 

• Identify and study potential sources for groundwater 

quality impacts at the park. 

• Install transducers and dataloggers in wells. 

• Investigate additional methods to characterize 

groundwater recharge areas and flow directions. 

Streamflow, Channel Morphology and Sediment Load 

Surface water is drained from Glacier National Park by 

many rivers flowing down slopes on either side of the 

continental divide. In the high alpine climate of 

northwestern Montana, intense, short duration, seasonal 

rainstorms and subsequent floods in addition to seasonal 

runoff from snow melt profoundly impact channel 

morphology. These intense events may also result in 

periodic deposits of deep sediments. 

Sediment loads and distribution affect aquatic and 

riparian ecosystems, and because sediment loading can 

result in changes to channel morphology and overbank 

flooding frequency. 

Inventory, Monitoring, and/or Research Needs 

• Monitor seasonal spring and stream locations with 

regards to their location, water quality, and maximum 

flow. 

• Perform channel morphology studies, with regards to 

intense seasonal runoff. Consult professional 

geomorphologists with regards to erosional processes. 

• Measuring sediment load and erosion rates would give 

a detailed view of problem areas in the park. 

• Changes in streamflow record basin dynamics, climate 

and land use. 

• Study the sediment influx for small alpine lakes in the 

park 

• Inventory current channel morphological 

characteristics. 

• Monitor changes in channel morphology. 

• Conduct hydrologic condition assessment to identify 

actual and potential “problem reaches” for prioritized 

monitoring. 

• Once “problem reaches” are identified, monitor with 

repeat aerial photographs. 

• Research effects of land use and climatic variation on 

streamflow. 

• Investigate paleoflood hydrology. 

• Conduct research concerning ungaged stream 

sediment storage and load. 

• Measure sediment load on streams of high interest for 

comparative assessment. Data will provide 

information for making management decisions. 

Wind Erosion and Deposition 

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

redistribute snow, soil, and other materials (e.g., litter, 

organic matter, and nutrients) within and among 

ecosystems. Erosion and deposition by wind is important 

at Glacier National Park and can be accelerated by 

human activities. Accelerated losses of soil and soil 

resources by erosion can indicate degradation of 

ecosystems because ecosystem health is dependent on 

the retention of these resources. In addition, wind 

erosion and sediment transport may be strongly 

impacted by land- use practices outside the park. 

Because park management practices limit or prohibit 

off- road travel, human impacts within the park primarily 

are associated with off- trail hiking in high- use areas. 

Inventory, Monitoring, and/or Research Needs 

• Monitor movement of soil materials. 

• Investigate ecosystem consequences of movement 

• Investigate natural range of variability of soil 

movement in relation to landscape configuration and 

characteristics. 

General Geology 

The Precambrian Era (4600 – 570 Ma) is notoriously 

difficult to decipher. Much of the rock record necessary 

for tectonic correlation with other areas is missing or 

buried beneath younger rocks. For this reason study of 

the Belt Supergroup rocks at Glacier National Park is 

crucial for understanding at least one setting from the 

Precambrian, but the rock record gap leaves a heavy 

reliance on the study of adjacent areas to determine the 

tectonic setting between the Precambrian and the 

Tertiary. 

An understanding of the geological processes and 

resources at Glacier is fundamental to management 

decision making. This report hopes to further this long 

term goal at Glacier with further suggestions and 

baseline information, including the digital geologic map 

of the park to be incorporated into a natural resources 

GIS for help in management decision making. However, 

for the scientific community and the general public, the 

geology of Glacier National Park offers vast 

opportunities to further the knowledge of alpine 

erosional processes, geologic and earth history. 
 GLAC Geologic Resource Evaluation Report 15

Inventory, Monitoring, and/or Research Needs 

• Perform rock color studies. 

• Identify unconformity- bounded stratigraphic 

packages in order to better define the depositional 

systems present in the past. 

• The continuing study and implementation of 

geographic information systems (GIS) technology for 

interpretation, resource management, and 

maintenance areas of park management through 

interpretive mapping, 3- D visualization, a virtual field 

trip, and surface rockfall hazard assessment (McNeil et 

al. 2002). Develop more graphics and brochures 

emphasizing geology. These should target the average 

enthusiast. 

• Contact for geologic training sessions: UGS Geologic 

Extension Services. 

• .The Belt Supergroup records rare Precambrian age 

environments, yet a detailed correlation of the rocks 

present in the Park and those found to the south, north 

and west has not been completed. 

• Continued study of why the northern Rocky 

Mountains exist so far inland from a continental 

margin. How compressional stresses were translated 

so far inland remains a geologic enigma. 

• Further research is needed to determine if the Belt 

basin was a open marine environment, or a restricted 

lacustrine (lake) environment. 
 NPS Geologic Resources Division 16 

Geologic Features and Processes 

Glacial Features 

The rugged landscape of Glacier National Park was 

formed by glacial processes. A glacier is a powerful agent 

of erosion, capable of profoundly altering the landscape 

over which is passes. Glaciers erode primarily by two 

distinct processes, plucking and abrasion (Dyson 1966). 

In plucking, the glacier actually quarries out distinct 

masses of rock, incorporates them within the ice and 

carries them along. As the glacier moves forward these 

blocks of rock are dragged or carried along with it 

(Dyson 1966). 

Bergshrunds 

Usually a large crevasse, the bergschrund, develops in the 

ice at the head of a glacier as a result of gravitational 

stresses pulling the glacier away from the headwall. The 

bergschrund of most active glaciers in Glacier National 

Park consists of an opening, usually 10 to 20 feet wide at 

the top and as much as 50 feet deep, between the head of 

the glacier and the mountain wall. It is at this site that 

plucking is most active and dominant because water 

enters by day and freezes in the rock crevices at night. 

Cirques 

By quarrying headward and downward the glacier finally 

carves the formation of a steep- sided, bowl- shaped 

basin called a cirque or glacial amphitheatre. The cirque 

is the first place that ice forms and the place from which 

it disappears last, thus it is subjected to intense glacial 

erosion longer than any other part of the glacial valley. A 

body of water known as a cirque lake may form in the 

depression after the glacier melts (Dyson 1966). Iceberg 

Lake, for example, lies in one of the most magnificent 

cirques in the park. 

Glacial Stairways 

Rock fragments of various sizes frozen into the bottom 

and sides of the glacier form a huge file or rasp which 

abrades or wears away the bottom and sides of the valley 

course down which the glacier flows. The valley thus 

attains a characteristic U- shaped cross section, with 

steep sides and a broad bottom. Practically all the valleys 

of the Park, especially the major ones, possess this 

distinct U- shaped cross section. Splendid examples are 

the Swiftcurrent Valley, St. Mary Valley, and the Belly 

River Valley. The floors of many of the Park’s major Ushaped valleys are marked by several steep drops or 

“steps”, between which the valley floor has a 

comparatively gentle slope. Such a valley floor is called a 

glacial stairway (Dyson 1966). These features result from 

the differences of erosional resistance between different 

rock types of the of the underlying formations. 

A glacier will scour more deeply into a weaker rock 

forming a “tread” in contrast to the cliffs or “risers” 

formed by the erosion of stronger rocks. Resistant layers 

in the lower portion of the Altyn Formation, the upper 

part of the Appekunny Formation, and the upper part of 

the Grinnell Formation normally create risers in Glacier 

National Park. 

Hanging Valleys 

The “tributaries” of glacial valleys, filled with smaller 

glaciers which feed into the larger ones, are known as 

hanging valleys. They form as a result of differences in 

erosional power between the smaller glacier and the 

valley glacier. The thicker a stream of ice, the more 

erosion it is capable of; consequently, the main valley 

becomes greatly deepened, whereas the smaller glacier in 

the tributary valley does not cut down so rapidly, leaving 

its valley hanging high above the floor of the major valley 

once all the ice melts (figure 4) (Dyson 1966). The valleys 

of Virginia and Florence Creeks, tributaries to St. Mary 

Valley are excellent examples of hanging valleys. 

Arêtes 

Conspicuous throughout the park are the long, sharp 

ridges which form most of the backbone of the Lewis 

and Livingston Ranges. These features, of which the 

Garden Wall is one of the most renowned, are known as 

arêtes and also owe their origin to glacial processes. As 

the long valley glaciers enlarged their cirques by cutting 

farther in toward the axis of the mountain range, the 

latter finally was reduced to a very narrow steep- sided 

ridge, the arête. In certain places glaciers on opposite 

sides of the arête essentially cut through the ridge 

creating a low place known as a col, usually called a pass 

(Dyson 1966). Gunsight, Logan, and Red Eagle passes are 

a few examples. At locations where three or more 

glaciers plucked their way back toward a common point, 

they left at their heads a sharp- pointed peak known as a 

horn. Reynolds, Bearhat and Clements Mountains are 

excellent examples of horns. 
 GLAC Geologic Resource Evaluation Report 17

Waterfalls and Lakes 

Other features of the park which can be attributed to 

glaciation, at least in part, are the spectacular waterfalls. 

There are two principal types of falls at Glacier. One 

occurs in the bottom of the main valleys, the other at the 

mouth of the hanging tributary valleys (Dyson 1966). The 

former exemplified by Trick Falls of the Two Medicine 

River, is located where the stream drops over the risers 

of the glacial stairway (see description above). Examples 

of the hanging tributary type of fall, are Bird Woman and 

Grinnell Falls. 

Most lakes throughout the Park also owe their existence 

directly or indirectly to glaciers. They may be divided 

into five main types, depending on their origin: 1) cirque 

lakes, 2) other rock- basin lakes, 3) lakes held in by 

outwash, 4) lakes held by alluvial fans, and 5) moraine 

lakes (Dyson 1966). 

Cirque lakes fill the depression plucked out of solid rock 

by a glacier at its source. Other rock- basin lakes fill 

depressions created where glaciers moved over areas of 

comparatively weak rock. In all cases of cirque or rockbasin lakes, the water is contained by a bedrock dam. A 

typical example of this type of feature is Swiftcurrent 

Lake. 

Lakes held in by glacial outwash are dammed by 

stratified gravel which was washed out from former 

glaciers when they extended down into the lower parts 

of the valleys. Lake McDonald exemplifies this type of 

lake. Lakes held by alluvial fans differ from the previous 

lake type in that they may have started as rock- basin 

lakes, but at a relatively recent date streams entering the 

lake valley have completely blocked the valley with 

deposits of gravel; thus creating a lake or raising the level 

of the one already present. St. Mary and Lower St. Mary 

lakes probably were joined originally, but the alluvial fan 

of Divide Creek, entering the basin from the south 

created a dam which cut the original lake body into two 

separate bodies. Finally, moraine lakes are formed when 

a moraine deposit blocks a stream outlet. Josephine Lake 

is a prominent example of a moraine lake. Another type 

of unique moraine lake has a glacier for part of its 

shoreline. In Glacier National Park, there are two of 

these lakes at Sperry Glacier and one at Grinnell Glacier. 

Glacial Deposits 

As the glacial ice moves it continually breaks rock 

fragments lose. Some of these are ground into a type of 

powder as they move against each other and against the 

bedrock under the glacier. Most types of rock, especially 

the limestones and shales on which the glaciers rest in 

Glacier National Park, yield a gray powder when finely 

ground. All melt- water streams issuing from presentday glaciers are cloudy or milky from their load of this 

finely ground “rock flour”. Much of this silt is deposited 

in lakes giving them a milky, turquoise color. 

Although the former large glaciers of the Ice Age 

transported huge amounts of rock debris down the 

valleys of the Park, the moraines which they deposited 

are, as a rule, not conspicuous features of the landscape. 

They are susceptible to intense erosion immediately 

following deposition as well as the obscuring effects of a 

vegetative cover of over 10,000 years The Going- tothe- Sun Road transverses a number of moraines along 

the shore of Lake McDonald. Because of the large 

proportions of rock flour (clay) in these accumulations, 

the material continually slumps, sometimes sliding onto 

the road surface. Knowledge of the location of such 

deposits is critical for maintenance of the road. 

Glacial Retreat 

In the late 1800’s, all 150 glaciers began to shrink in 

response to a slight change in climate, probably involving 

both a temperature rise and a decrease in annual 

precipitation. From about 1900 to 1945 glacial retreat was 

very rapid (Dyson 1966). Over a period of several years 

such shrinkage is apparent to the eye of an observer and 

is manifested by a lowering of the glacier’s surface 

elevation and a reduction of surface area. When the 

yearly snow accumulation decreases, the ice front of the 

glacier seems to retreat or move back, whereas the mass 

of the glacier is merely decreasing by melting on top and 

along the edges, analogous to an ice cube melting on a 

kitchen counter. 

Six glaciers mapped from 1993 aerial photos, and two 

others mapped through 1979, retreat from 1850 maxima 

ranged from 818- 1440 m and averaged 1244 m. Overall 

retreat rates varied between 6- 17 m/yr. Those glaciers 

were reduced in area by 62- 80%, for an average 

shrinkage to 27% of the estimated area in 1850. Retreat 

rates were never constant over time on any single glacier, 

but roughly correlative with warmer climate trends. 

Pulses of recession occurred during the 1920’s through 

the mid- 1940’s, and seem to be recurring now, as 

evidenced by dramatic change in glacier size since 1979. 

This inconsistency also means there have been periodic 

glacial advances throughout recorded history in Glacier 

National Park. Between 1966 and 1979, several of the 

larger glaciers in the Mount Jackson area advanced as 

much as 100 m (Key et al. 1996). This means that glacial 

response to climatic trends is very rapid, and could be 

relevant to the recent worries about the greenhouse 

effect and global warming. 

Recent moraines of two different age groups have been 

identified fronting the present- day glaciers and 

snowfields in Glacier National Park, ranging in size from 

a few m to more than 60 m (200 feet) (Dyson 1966; 

Carrara 1987). The subdued, vegetated moraines (sparse 

willows and other forms of dwarf vegetation) of the older 

group have been found at 25 sites, mainly in the central 

part of the Lewis Range. 
 NPS Geologic Resources Division 18 

These older moraines are in places overlain by volcanic 

ash from the eruption of Mount Mazama (now Crater 

Lake) in Oregon and therefore must predate the 6,800 

year old B.P. event (Carrara and Wilcox 1984; Carrara 

1986; Osborn and Gerloff 1997). 

The younger set of moraines, which has accumulated 

during the last several hundred years, consists of fresh 

bouldery rubble on which only small pioneer plants and 

lichens have begun to establish themselves. They are 

common throughout Glacier Park (Dyson 1966; Carrara 

1986). Tree- ring analyses indicate that some of these 

younger moraines were deposited by advances that 

culminated during the mid- 19th century (Carrara and 

Wilcox 1984; Carrara 1986). The moraines are particularly 

striking at Grinnell, Sperry, Blackfoot, Agassiz and 

Sexton Glaciers. Because of recent glacial retreat most, if 

not all, of the glaciers are no longer in contact with these 

newer moraines. In some cases a quarter of a mile or bare 

rock surface intervenes between the moraine and the 

glacier terminus (figure 5) (Dyson 1966). 

A few glaciers have disappeared within recent years, but 

their distinctive moraines remain as evidence of former 

glacier activity. One of the most notable examples is the 

former Clements Glacier, a small body of ice which 

existed until about 1938 in the shadow of Clements 

Mountain at Logan Pass. The trail to Hidden Lake skirts 

the outside edge of the moraine. Between the mountain 

and moraine lies an obvious, bare expanse of rock where 

the Clements Glacier once existed (Dyson 1966). 

Glaciers 

Some 37 named glaciers (50- 60 total) currently exist in 

various cirque, niche, ice apron, group and remnant 

forms in Glacier National Park (Key et al. 1996). Only 

two have surface areas of nearly one- half square mile, 

and not more than seven others exceed one- fourth 

square mile in area (Dyson 1966) (figure 6). 

All the present- day bodies of ice in Glacier National 

Park lie at the heads of valleys with high steep headwalls, 

on the east and north sides of high ridges at elevations 

between 6,000 and 9,000 feet, in all cases well below the 

snowline (the elevation above which more snow falls in 

winter than can be melted or evaporated during the 

summer, about 10,000 feet in Glacier). Consequently, 

these glaciers owe their origin and existence almost 

entirely to wind- drifted snow (Dyson 1966; Allen et al.

1995). Ice within these glaciers moves slowly. The 

average rate in the smallest ones may be as low as 6 to 8 

feet a year, and in the largest glaciers probably 25 to 30 

feet a year. 

There is no time of year when the glaciers are motionless, 

although movement is somewhat slower in winter than in 

summer. Despite its slow speed, over a period of years, 

the glacial ice transports large quantities of rock material 

ultimately to the glacier’s end where it is piled up in the 

form of a moraine. The largest glacier in the Park is 

Grinnell Glacier. In 1960 it had a surface area of 315 acres. 

Sperry Glacier is the second largest glacier in the Park. Its 

surface in 1960 was 287 acres (figure 7). Both Grinnell 

and Sperry Glaciers probably have maximum thicknesses 

of 400 to 500 feet (Dryson 1966; Key et al. 1996). Retreat 

has continued since 1960 and the glaciers are all much 

smaller now. 

Other important Park glaciers, although much smaller 

than the first two mentioned, are Harrison, Chaney, 

Sexton, Jackson, Blackfoot, Siyeh, and Ahern Glaciers. 

Several others approach some of these in size, but 

because of isolated locations they are seldom measured. 

There are people who visit Glacier National Park 

without seeing a single glacier, while others, although 

they actually see glaciers, leave the park without realizing 

they have seen them. This is because the roadways afford 

only distant views of the glaciers, which from a distance 

appear as mere accumulations of snow. 

Short-lived Glacial Features 

There is a myriad of interesting, short- lived surface 

features which can be seen at times on any glacier. These 

include crevasses, moulins (glacier wells), debris cones, 

and glacier tables (figure 8). Crevasses are cracks which 

occur in the ice of all glaciers due to tensions caused by 

differences in ice velocity throughout the body of the 

glacier. They can be hidden by skiffs of snow or debris 

and thus can pose an access problem to visitors. Debris 

cones result from the insulating effect of rock debris, 

usually deposited by a stream running over the glacier’s 

surface, which protects the ice underneath from the 

sun’s rays. As the surface of the glacier is lowered by 

melting, cones or mounds form beneath the rockinsulated area and grow gradually higher until the debris 

slides from them. They are seldom higher than 3 or 4 feet, 

but can pose a hazard to hikers on the glacier. A glacier 

table is a mound of ice which is capped and insulated by 

a large boulder. Its history is similar to that of the debris 

cone or mound (Dyson 1966). Snow which fills crevasses 

and wells during the winter often melts out from below 

leaving thin snowbridges over the cracks in the early part 

of the summer. These pose a very real danger to those 

traveling on a glacier because of their inherent weakness 

and instability. 

The Belt Supergroup 

Glacier National Park contains the best exposed and 

most complete sections of the Belt Supergroup rocks. A 

partial section of the Belt Supergroup is about 2900 m 

(9514 ft) thick in the central and northeastern margin of 

the Park, with the base being in fault contact with 

underlying Cretaceous strata and the top having been 

removed by erosion. Neither the base nor the top of the 

Belt Supergroup is present anywhere in Glacier National 

Park. Although these strata were subjected to lowermost 

greenschist- facies metamorphism (~300oC and 2 Kbar), 

details of sedimentary structures and fine sedimentary 

laminae are extremely well preserved, and for the 

purposes of sedimentary study are considered to be 

essentially unmetamorphosed (Horodyski 1983). 
 GLAC Geologic Resource Evaluation Report 19

Because they were deposited before the evolution of 

complex plants and animals, the Belt Supergroup 

provides a unique context to study ancient sediments 

undisturbed by the bioturbation ubiquitous with younger 

rocks. The only organisms present to leave their mark on 

Belt rocks are stunningly variable stromatolites or algal 

mats present in many rock formations of Glacier 

National Park (figure 9). 

The Belt Supergroup is generally regarded to be of 

Middle Proterozoic age (~1100 – 1850 Ma), but its exact 

span within the Middle Proterozoic is poorly 

constrained. It was deposited in either (1) a large 

intracratonic rift basin, like the East African Rift Zone, or 

(2) a passive margin, such as that along the present day 

eastern United States (McGimsey 1985; Moe et al. 1996). 

There has been considerable discussion about whether 

the Belt Supergroup rocks were deposited in a basin that 

was marine (open ocean) or lacustrine (constrained, 

fresh water). Evidence points to either possibility in the 

Belt basin (figure 10). Winston (1986) proposed a 

lacustrine intracratonic basin for the deposition of the 

Belt Supergroup, however, Hoffman (1988) suggested an 

episutural basin (a basin which persists between two 

converging land masses) underlain by oceanic crust 

trapped in the North America continent. Whether 

marine or lacustrine, what all researchers agree upon is 

that the Belt Supergroup was deposited in a largely 

shallow basin with a variety of nearshore and subaerially 

exposed deposition environments recorded in the rocks 

of Glacier National Park. 

In either hypothesized depositional environment, the 

Belt Supergroup was deposited in water, with a variety of 

near and far shore environments recorded in Glacier’s 

rock formations. The carbonate units record deeper 

water environments as do fine- grained clay rich rocks. 

Sandstones and desiccated mudstones record beach and 

other near shore subaerially exposed deposition sites. 

The ancient Belt basin was a dynamic system intimately 

tied to the surrounding tectonic setting. 

Faults at Glacier 

The Proterozoic rocks at Glacier are now exposed at the 

surface because of the movement associated with the 

Sevier- Laramide orogeny along the Lewis thrust fault. In 

Glacier, the Lewis thrust fault not only underlies the 

entire park, but is responsible in part for the rugged 

alpine scenery. The fault initiated intermittent 

deformation and movement some 200 million years ago 

and ceased some 15 million years ago. 

The Lewis thrust fault, discovered and named by Willis 

in 1902, juxtaposes mid- Proterozoic Belt Supergroup 

rocks (~1600 million years old) in its upper plate with the 

late Cretaceous age Marias River Shale (~90 million years 

old) in its lower plate. The surface of the fault is usually 

covered by talus and other slope debris which makes it 

difficult to measure the surface directly. 

Ross (1959) described the average strike, or compass 

direction of a horizontal line of intersection of a plane 

with Earth’s surface, of the thrust fault in this area as 

N30oW and the dip of the gently folded fault surface as 

generally less than 10o SW. From a point 225 km (140 mi) 

north of the International boundary, the fault extends 

southward for 452 km (281 mi) (McGimsey 1982). 

Maximum translation, or horizontal distance the fault 

has moved, of the Lewis thrust is approximately 65 km 

(40 mi), this measurement was inferred from a location 

along the southern edge of the Glacier. The fault is 

located at an elevation of about 1829 m (6000 ft) along 

the eastern edge of Glacier National Park, and dips down 

to less than 1372 m (4500 ft) in elevation in western areas 

of the Park (Yin 1988). 

The Lewis thrust has long been considered the “classic” 

example of an overthrust. The architecture of the Lewis 

thrust is extremely complex. It consists of symmetric and 

asymmetric concentric folds, high- angle and low- angle 

contractional and extensional faults, zones of complex 

structures, and imbricate thrust systems (Yin1988). The 

fault overlies the Cretaceous age rocks of the disturbed 

belt; a narrow north- south trending strip of land to the 

east of Glacier National Park (figure 11). Individual faults 

within the disturbed belt are difficult to distinguish given 

the extreme, pervasive deformation. East of the 

disturbed belt lies the Sweetgrass Arch and associated 

Kevin Sunburst Dome. These features are likely the 

results of flexural folding of the crust in response to the 

weight of the thick rock column to the west (Lewis thrust 

sheet). The Lewis thrust sheet (column of rock above the 

fault surface) is several kilometers thick, and is 

characterized by broad open folds in relatively 

undeformed rocks. 

The Lewis thrust sheet is offset by the Flathead- Blacktail 

normal fault zone in the North Kootenay Pass and 

Marias Pass areas (Yin 1988). This indicates that after the 

Lewis thrust ceased movement around 15 Ma, the 

younger normal faults became dominant. The Flathead 

fault is a family of major listric normal faults (Flathead, 

Blacktail and Roosevelt faults) with an average high angle 

(40o or greater westward dip), but seismic data indicates 

the fault flattens with depth and may either sole into or 

just offset the Lewis thrust at depth. Displacement along 

the Flathead fault is estimated to be at least 13 km (8 mi) 

(McGimsey 1982; Yin 1988). 

Running along the western edge of Glacier National Park 

is the Kishenehn Basin. This basin formed on the downdropped side of the Flathead- Blacktail normal fault 

system. As the Roosevelt (to the west) and FlatheadBlacktail normal fault systems sole into and locally offset 

structures in the Lewis thrust sheet, the Roosevelt and 

Flathead- Blacktail fault postdate the Lewis thrust fault. 

Thus, the Tertiary age of the Kishenehn basin 

presumably provides an upper limit for the movement 

along the Lewis thrust (Yin 1988). The basin is very deep, 

more than 600 m (1969 ft). 
 NPS Geologic Resources Division 20 

These faults are among a number of roughly parallel 

faults west of Glacier National Park which sole into the 

Lewis Thrust fault. They record the extensional tectonic 

regime which followed the orogenic compressional 

events in the Rocky Mountains. 

Akamina Syncline 

The prominent syncline, the Akamina Syncline, running 

up the axis of the park is a broad open structure which 

lies totally within the upper plate of the Lewis thrust 

(figure 12). The trend of the syncline is roughly parallel to 

the strike of the thrust and numerous local normal faults 

in the Glacier National Park area (McGimsey 1982). The 

Akamina syncline is a doubly plunging structure (a fold 

that reverses its direction of plunge within an area, 

resembles the surface of a upturned bread loaf) that 

occupies the entire Lewis salient (portion of the thrust 

sheet which projects further than surrounding areas) 

from North Kootenay Pass to Marias Pass. It records the 

structural low, bowl shaped depression, in which the 

Park lies. Regionally, the Akamina syncline is bounded 

by the Lewis thrust to the east, and the FlatheadBlacktail normal fault system to the west. Within Glacier 

National Park, the hinge or axis of the syncline follows 

the continental divide and ends at the south- central edge 

of the Park (Yin 1988). 
Hanging valleys 

U- Shaped 

Figure 4: Three hanging valleys left as remnants of former glaciers flowing into the larger that once occupied the U-shaped valley 

running up the axis of the image. Modified from photo by Dawes and Dawes 2001. For more information see: 

http://wvcweb.ctc.edu/rdawes/VirtualFieldSites/GrinnellGlacier/VFSGrinnell.html

 GLAC Geologic Resource Evaluation Report 21
Figure 5: Diagrammatic view of a retreating glacier with a recent terminal moraine and a broad space between the moraine and the 

glacier front. Note the variety of deposits associated with glacial melt. 

 NPS Geologic Resources Division 22 
Figure 6: Map of Glacier National Park showing locations of the largest glaciers present today. Modified from Dyson 1966. 

 GLAC Geologic Resource Evaluation Report 23
Figure 7: The aerial extent of Sperry Glacier reflecting steady glacial retreat from 1850-1993. Modified from Key et al. 1996 

Figure 8: Short-lived surface features on glaciers. 

 NPS Geologic Resources Division 24 
Figure 9: Formation of stromatolites from a combination of precipitation of calcium carbonate from seawater and layers of blue green 

algae. 

 GLAC Geologic Resource Evaluation Report 25
Figure 10: Location of Glacier National Park relative to the entire Belt Terrane (basin). 

 NPS Geologic Resources Division 26 
 GLAC Geologic Resource Evaluation Report 27

Figure 11: Structural features east of Glacier National Park. Note the structure contour lines recording the elevation below the surface 

of the top of the Cretaceous age Colorado Group rocks. The contours record the subsurface depression the Park is situated in. 
Figure 12: Prominent structural features inside Glacier National Park, including Akamina syncline. Modified from McGimsey 1982 

 NPS Geologic Resources Division 28 
 GLAC Geologic Resource Evaluation Report 29

Formation Properties 

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

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

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

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

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

Resources Division at 303- 969- 2090. 

Glacier National Park is underlain almost entirely by 

Proterozoic age rocks. Beneath the Lewis thrust fault and 

filling valleys are Cenozoic age rocks. Because of the 

intense regional erosion these rocks are on striking 

display, indicative of the history of the area. 

The oldest rocks of the area, composing the Ravalli 

Group, the Middle Belt Carbonate and the Missoula 

Group are Late Proterozoic in age. These were deposited 

in an ancient Belt sea basin. In the early Cretaceous Era, 

the sediments deposited include the sands, silts and 

muds for the Kootenai, Willow Creek, St. Mary River, 

Telegraph Creek, Two Medicine, and Blackleaf 

Formations, the mud for the Marias River and Bearpaw 

Shales, and the sand for the Virgelle and Horsethief 

Sandstones. 

The late Cretaceous to early Tertiary compressional 

Sevier–Laramide orogenic events caused huge blocks of 

buried rock to slide over younger rock in an easterly 

direction. These episodes caused the dramatic 

juxtaposition of rock ages found today at Glacier. The 

Tertiary age Kishehnehn Formation is the result of the 

local basins filling with sediments when extension along 

normal faults followed mountain building. Pleistocene 

glaciation and other geomorphological agents such as 

streams and landslides have all left recent, Quaternary 

age deposits on the landscape of Glacier National Park. 

Formation Properties Table 

The following three pages present a table view of the 

stratigraphic column and an itemized list of features per 

rock unit. This table includes several properties specific 

to each unit present in the stratigraphic column 

including: map symbol, name, description, resistance to 

erosion, suitability for development, hazards, potential 

paleontologic resources, cultural and mineral resources, 

potential karst issues, recreational use potential, and 

global significance. 

Geologic History 

The story at Glacier begins in the Proterozoic Eon (see 

Figure 21). Little is known about this period of earth’s 

history. Most rocks on earth of Precambrian age are 

incredibly deformed and metamorphosed, losing most, if 

not all traces of their original structures. Glacier, 

however, hosts one of the most pristine Precambrian 

sedimentary records on earth. It is by examination of this 

rock record that the tectonic history of the region is 

revealed. 

The Proterozoic rocks at Glacier are part of the Belt 

Supergroup. This name refers to a stack of rocks formed 

in the ancient Belt basin that covered large parts of 

Montana, Idaho, Alberta, and Washington. The Belt 

basin formed in response to high angle faulting and 

subsidence of large continental basement rock blocks, 

veneered by a discontinuous blanket of quartz sand. 

Dark quartzite, argillite, and carbonate of lower Belt 

formations including the Prichard, Altyn and Appekunny 

mark the first and most extensive spread of the great Belt 

lake over basement crystalline rocks (Winston 1989b). 

Perhaps the most striking tectonic event during lower 

Belt deposition was block faulting along the Perry line, 

which uplifted the Dillon crustal block of the Archean 

Wyoming province to the south and downdropped 

crustal rocks to the north, forming the southern margin 

of the basin (figure 13). The resulting eastern indentation 

is called the Helena embayment and comprises an arm of 

the Belt basin. The Prichard, Altyn and Appekunny 

Formations filled the main part of the basin that 

extended across western Montana, northern Idaho, and 

into eastern Washington (Winston 1989b). 

The western side of Glacier National Park has the dark 

gray to nearly black quartzite and argillite as well as 

graded arenite beds of the Prichard Formation (Winston 

1989; Winston 1989b). Most of the Prichard formation is 

composed of subaqueous, sub- wave base, pelagic and 

turbidite deposits that pass to the deltaic facies in the 

west, reflecting sediment influx from the west of the Belt 

basin (Winston 1989). Interlayered carbon- poor and 

carbon- rich sediments indicate alternating oxygenated 

and anoxic, stagnant bottom conditions for the Belt 

basin. Paleocurrent data from western Prichard 

exposures indicate that the basin deepened eastward to 

the vicinity of the Purcell anticlorium, west of Glacier 

National Park, near Libby, Montana, where currents 

were deflected northwestward (Winston 1989b). 

Simultaneously, sediments entering the eastern, more 

tectonically stable side of the basin, appear to be limited 

to coarse quartz sand, most likely reworked from the 

Neihart sediments. The coarse sand was mixed with 

carbonate mud forming the micritic limestone - 

sandstone mixture of the Altyn Formation, now present 

along the eastern side of Glacier National Park (figure 14) 

(Winston 1989; Winston 1989b). Micrite deposition along 

the eastern and northeastern margin of the basin 

probably reflects tectonic stability of the Archean craton 

to the east and south. 

The Altyn is overlain by black, green and red argillite and 

coarse- grained arenite of the Appekunny Formation. 

Deposition of the siliciclastic Appekunny Formation 

over the Altyn Formation may reflect the filling of the 

Purcell trough (with sediments of the Prichard 

Formation) and the spreading of suspended mud from 

the west across the eastern part of the basin (Winston 

1989). 

From the relatively quiet, subaqueous, evenly layered 

deposits of the lower Belt formations, the upward 

transition into the ripplemarked, mudcracked redbeds of 

the Ravalli Group indicate progradation of playas and 

alluvial aprons from the west across the Belt basin 

(Winston 1989b). In other words, the advance of 

continental environments, as opposed to marine, broadly 

across the basin (figure 15). The dominantly redbed 

Ravalli Group is represented in Glacier National Park by 

the Grinnell Formation, and the green argillite unit, the 

Empire Formation. 

The well- exposed Grinnell Formation records the 

intermittent emergence of subaerial shoreline in the Belt 

basin. The lowermost units of the Grinnell record 

subaqueous accumulation of sediments settling from 

suspension, and being partly reworked by wave 

oscillation. Upsection, desiccated mud, indicates 

exposure on extensive flats. Thin, rare beds of mediumto coarse- grained sand record ephemeral flooding 

across these exposed mud flats (Kuhn 1987). Periodic 

floods ripped up mudcracked polygons and moved them 

as mudchips to be deposited as unique thin 

conglomeratic beds. Laterally continuous silt beds, 

indicate sheetlike deposition over broad, flat surfaces, 

with occasional microlaminated beds recording 

submergence. The increasing amounts of coarser grained 

sand upsection signal the return to a prograding sandflat 

(Kuhn 1987). Westward thinning of the sand layers 

within the Grinnell indicates an eastern source terrain 

for medium- to coarse- grained sand in the Ravalli 

Group (Winston 1989). 

The Empire Formation is dominated by shallow water 

rippled and mudcracked rocks (Winston and Lyons 

1993). With deeper water facies increasing gradually 

upsection. The green argillite of the Empire Formation 

on the eastern side of the Belt basin becomes calcareous 

and tan weathering upsection. The upsection change 

from redbeds of the Grinnell Formation into greenbeds 

at the base of the Empire Formation signals submergence 

and the onset of the Middle Belt carbonate progression 

across the Belt basin (Winston 1989b). 

 GLAC Geologic Resource Evaluation Report 33 
 NPS Geologic Resources Division 34 

The first change recorded in the Empire is water 

deepening and a shift from oxidizing to reducing 

conditions. The second dramatic change recorded in the 

Empire is the decline of the supply of terrigenous clastic 

material, from both the eastern and southwestern 

sources. This clastic supply was replaced by carbonate 

mud (Link 1993). 

The Helena Formation, consisting of a thick sequence of 

interlayered siliciclastic and carbonate cycles, represents 

the eastern facies of the Middle Belt carbonate. The 

Helena contains deeper water sediments than the 

underlying Empire Formation, recording an overall 

transgression of the sea onto the shoreline. The 

sediments fine and thin eastward. This is interpreted to 

record periodic turbidite underflows and interflows 

from the west that spread out above the sub wave base 

floor of the Belt basin (Winston 1989) (figure 16). The 

sediment may have come mostly from floods that 

drained the western side of the basin. Along the eastern 

side of the basin, authigenic carbonate mud precipitation 

overwhelmed siliciclastic influx forming the carbonate 

mud sediments there. The occasional siliciclastic beds in 

the Helena Formation record the episodic expansion of 

the Belt “sea” across subjacent exposed surfaces in 

response to wetter climatic conditions. Erosion scoured 

the carbonate flats exposed as the shoreline further 

regressed seaward, shifting the carbonate deposition 

westward. 

The outcrop extent of the Helena Formation is immense. 

Today is extends from eastern Washington to Glacier 

National Park, which shows that, during its maximum 

spread, the Belt sea had a fetch of more than 300 km, and 

this is not including the western edge of the basin, now 

lost as described earlier. This inferred basin is 

comparable in scale to the northern part of the modern 

Caspian Sea (Winston and Lyons 1993). 

Above the Helena Formation is a thick sequence 

dominated by red argillite, pink arenite and green 

argillite, containing some carbonate and black argillite 

intervals. These rocks comprise the formations of the 

Missoula Group, which are from bottom to top: the 

Snowslip Formation, the Shepard Formation, the Mount 

Shields Formation, the Bonner Quartzite, and the 

McNamara Formation and several others not exposed at 

Glacier National Park (the Garnet Range Formation, and 

the Pilcher Formation). Major transgression and 

regression of the Belt sea during Missoula Group 

deposition resulted in four progradational sequences 

separated by transgressive (highstand) sequences (figure 

17). The Snowslip and Mount Shields (lower beds) 

Formations, the Bonner Quartzite and upper McNamara 

Formation comprise the major progradational sequences 

whereas the remaining rocks comprise the transgressive 

(deeper water) sequences. The progradational deposits 

probably reflect periods of tectonic uplift in the Belt 

source area and a corresponding downdrop of the basin 

(Ackman 1988) (figure 18). 

The red argillite of the Snowslip that characterizes the 

base of the Missoula Group passes progressively 

westward to green argillite, thus the westward correlative 

of the Snowslip becomes green and black argillite, 

overlain by black argillite and carbonate of the Shepard 

Formation correlative unit (Winston 1989). This indicates 

deeper water environments progressively westward in 

the Belt basin at the time of the initial Missoula Group 

deposition. The red argillite also records the regressional 

environment that signaled the end of Helena Formation 

deposition as the mudflats were exposed. Alluvial aprons 

of great areal extent bordered the uplifted continent 

southwest of the Belt basin and sloped gently into the 

Belt sea. 

Missoula Group rocks record the changing of sea level 

along this alluvial apron. During lowstand conditions, 

the variety of shoreline environments including: 1) 

braided flood channels filled with cross bedded sand, 2) 

shallow sheetflood tracks, 3) shallow ponds with mud 

layers and small- scale ripplemarks, 4) exposed, 

desiccated mudflats, vulnerable to rip- ups during 

occasional floods, 5) broad sandflats, and 6) beaches, all 

moved progressively basinward whereas in transgressive 

situations, these environments retreated from the basin 

towards the craton. 

The Snowslip Formation is representative in its record of 

the variety of environments present during Missoula 

Group Formation. From deposition on distal sandflats, 

exposed mudflats and submerged mudflats during 

shoreline transgression, to basinward progradation of 

the alluvial aprons (Ackman 1988; Winston 1989). Some 

beds contain laminated sand, sheetflood deposits, 

desiccation cracks and abundant mudchips, ripped up 

during occasional floods over the increasingly exposed 

apron (Ackman 1988). The Purcell Lava, which is a basalt 

flow (1,075 m.y.) in the Snowslip, as well as gabbroic sills 

and some dikes of similar age provide isotopic dating 

opportunities. Pillow basalts of the Purcell Lava poured 

out into the waters of the Belt sea and were succeeded by 

a regressive sequence of red microlaminated beds 

capped by lenses of coarse sand and larger clasts and 

stromatolites (figure 19) (Winston 1989). 

The base of the Shepard Formation is marked by thin 

beds of coarse sand and larger clast sediments and 

stromatolites. These deposits were overlain by dark 

carbonaceous beds, signaling deeper water and a 

transgression of the great Belt sea (Winston 1989). The 

middle and upper parts of the Shepard are composed of 

calcareous varieties of sediments. During Missoula 

Group deposition, when terrigenous sediment was not 

included in carbonate deposits, this is interpreted to 

indicate quiet, protected environments of the Belt sea at 

this time, not necessarily deeper water conditions 

(Ackman 1988). 
 GLAC Geologic Resource Evaluation Report 35

Carbonate mud in the northwestern part of the basin was 

succeeded by widespread development of 

microlaminated, fine- grained sediment record 

expansion, transgression and freshening of the Belt sea 

high in the Mount Shields Formation. The pink 

crossbedded, coarse- grained sand of the Bonner 

Quartzite records yet another progradational advance of 

the alluvial apron complex from the southwest across 

Montana, north into Canada. The argillite of the 

overlying McNamara Formation records another 

transgressive drowning of the alluvial aprons and 

advance of playa flats. A wedge of sand sediment high in 

the McNamara marks progradation of a final alluvial 

apron complex in the southern part of the basin from 

that direction (Winston 1989). 

Rocks of Mesozoic age are not present at Glacier 

National Park. They were eroded from the uppermost 

reaches of the Belt Supergroup rocks upon uplift along 

the Lewis thrust fault. This missing rock record makes 

determining the paleoenvironment of the Mesozoic at 

Glacier very difficult. Geologists refer to surrounding 

areas to determine the history in a regional context. This 

report is focusing on the map units (rocks) present at 

Glacier National Park today. Reference texts on the 

history of the Rocky Mountain Region should be 

consulted for further information. 

The Cretaceous age rocks, present in limited exposure 

beneath the Lewis thrust sheet and east of the fault in 

Glacier record a myriad of marine environments present 

during the intermittent progradations and regressions of 

the Cretaceous Interior Seaway. These units include the 

Kootenai, Blackleaf, Telegraph Creek, Two Medicine, 

St. Mary, and Willow Creek Formations, the Marias 

River and Bearpaw Shales, and the Horsethief and 

Virgelle Sandstones. The fossils contained in these rocks 

indicate incredible biodiversity during this time and 

should be protected. 

During the Cretaceous- age Sevier Orogeny (about 105 to 

75 Ma), great sheets of sedimentary rocks that covered 

miles of terrain were thrust westward from what is now 

western Nevada into central Utah, a distance of roughly 

500 km (300 mi). The emplacement of these thrust sheets 

can be seen today in the mountains of Arizona, Utah, 

Wyoming, Montana, and Idaho. The Sevier Orogeny 

showed an example of thin- skinned thrust faulting 

wherein just the upper sedimentary strata of Earth’s crust 

were transported on laterally extensive thrust planes that 

dip at a low angle, generally 10- 15 degrees, from the 

horizontal surface of Earth. In contrast, thrust faults 

associated with the Late Cretaceous- Early Tertiary 

Laramide Orogeny are thick- skinned, that is, they are 

faults with nearly vertical fault planes at the surface of 

Earth that flatten and sole out in Precambrian basement 

crystalline rock at depths up to 9,000 m (30,000 ft) below 

sea level (Gries, 1983; Erslev, 1993). 

During the Laramide Orogeny, tectonic forces folded 

and faulted the entire geologic column, from 

Precambrian to Cretaceous age rocks, into the northsouth trending Rocky Mountains and adjoining basins 

(Graham et al. 2002). 

At one time, the Proterozoic Belt Supergroup and 

overlying rocks were buried beneath thick deposits of 

Cretaceous strata. Then the Laramide orogeny started. 

The Lewis thrust fault, though having moved 

intermittently for some 200 m.y., became the primary 

plane of movement for the massive rock column 

containing the Belt Terrane. This column moved 

eastward some 10’s of miles. This changed the Glacier 

area, once underwater during the tenure of the interior 

seaway into a mountainous highland. The Laramide 

event transformed the extensive basin of the Cretaceous 

Interior Seaway into smaller interior basins bordered by 

high arches (anticlines and synclines on the scale of 

miles) (Ehrlich 1999). The Laramide Orogeny (active 

from about 75 to 35 Ma) is one of the more perplexing 

episodes in the structural history of the Rocky 

Mountains. The orogeny affected rocks hundreds of 

miles inland from the continental margin where the socalled Farallon plate was subducting beneath North 

America. Modern geologists have struggled with models 

to predict these results (Graham et al. 2002). 

By 20 Ma, only remnants of the Farallon plate remained. 

The San Andreas strike- slip fault system between the 

Pacific plate and the North American plate began to 

grow and as it lengthened, the southwestern margin of 

North America began to undergo extensional 

deformation. As the crust was extended around 15 Ma, 

the surface began to be broken into the basin- and- range 

topography we see today in western Utah, Nevada, 

Arizona, and the Rio Grande Rift in New Mexico. In 

summary, from the Late Cretaceous to the Late Tertiary, 

the tectonic regime on the western margin of the North 

American continent changed from a steeply- dipping 

subduction zone to flat- plate subduction to extension 

caused by a growing transform fault system (Graham et 

al. 2002). 

This extensional tectonic setting in Tertiary time is 

recorded in the array of normal faults in Glacier National 

Park. These include the Roosevelt, Flathead and 

Blacktail faults as well as many parallel faults west of the 

park. When one block of rock falls relative to another, 

the resulting graben valley forms a substantial sediment 

sink. Such was the case for the North Fork valley and the 

resulting sedimentary fill, the Tertiary Kishenehn 

Formation (figure 20). The Kishenehn is characterized by 

its variety of sediments ranging from sandstone, 

mudstone, limestone, and coal to volcanic ash deposits. 

This assortment indicates the tectono- climatic variations 

during the Tertiary. The volcanic ash records volcanic 

activity along the western margin of North America, 

mostly in the Cascade Mountains of Oregon and 

Washington. 
 NPS Geologic Resources Division 36 

The limestone and coal seams imply the presence 

intermittent ponds and restricted lakes that formed in 

the graben. These occur in isolated patches probably 

indicating a relatively dry climate. However, the 

abundant petrified wood specimens in the Kishenehn 

Formation indicate that the climate was not desert like, 

but wet enough to support abundant plant life. 

The Quaternary Period is subdivided into two epochs: 1) 

the Pleistocene, which ranges from about 1.6 Ma to 

10,000 years before present (B.P.), and 2) the younger 

Holocene Epoch that extends from 10,000 years B.P. to 

the present. The Pleistocene Epoch is known as the Ice 

Age and is marked by multiple episodes of continental 

and alpine glaciation. Great continental glaciers, 

thousands of feet thick, advanced and retreated over 

approximately 100,000- year cycles. Huge volumes of 

water were stored in the glaciers during glacial periods so 

that sea level dropped as much as 300 feet (Fillmore, 

2000). When sea level lowered, land bridges emerged 

such as the Bering Land Bridge that linked North 

America and the Eurasian continents. During interglacial 

periods, Earth warmed and the glaciers retreated toward 

the polar regions. Sea level rose and the great land masses 

were once again isolated (Graham et al. 2002). 

Glaciers played a huge role in forming the landscape now 

present in Glacier National Park. This role is manifested 

in the glacial features and deposits now omnipresent in 

the Park. These deposits include huge terminal and 

lateral moraines which record the greatest glacial extent. 

Many of these deposits dam glacial valleys resulting in 

the narrow lakes so characteristic of the Park. Jumbled 

glacial till, esker, and outwash deposits are strewn along 

every valley traversed by a glacier in the Park. These 

impacts are described in detail in a following section. 

Quaternary age rocks in Glacier are represented by the 

glacial deposits from the Pleistocene and Holocene and 

recent alluvial gravel deposits, present along Glacier’s 

myriad of streams and rivers. Landslide and slope 

deposits are also prevalent in recent sediments due to the 

spectacular relief of the Park. 

The Holocene, of course, is the Age of Humans and our 

impact on our global ecosystem is complex. With the 

retreat of the glaciers and the end of widespread 

glaciation about 12,000 years ago, the climate continued 

to warm and global sea level rose. In some local areas 

(i.e., the coast of Maine and the Great Lakes region), 

however, relative sea level lowered as the land 

rebounded from the weight of the glaciers. 

Local tectonism, sediment input, global warming, and 

global cooling are some of the factors affecting global sea 

level and their relative importance, and humans’ 

influence on them, continues to be debated today 

(Graham et al. 2002). Climate change is readily 

observable in the retreat of the Park’s remaining glaciers. 

The response time of a glacier to climate change is rapid 

and the recent melting rate serves to substantiate the 

greenhouse effect hypothesis. 

The Glacier Park area is experiencing significant growth 

in population. The Park boundaries are being inundated 

with the effects of development. Man- made bridges, 

roads and dams, such as the Hungry Horse Dam in 

Hungry Horse, Montana change the course of rivers and 

sediment deposition. Questions constantly arise about 

how to balance man’s use of nature with its preservation. 
Figure 13: Map of present day structural features in the Glacier National Park area superimposed on Mid-Proterozoic fault lines (blue) 

with cratonic blocks labeled in green. Red lines indicate fold axes, black lines with teeth indicate thrust faults with teeth on overriding 

plate, black lines with bar and ball show normal faults with the symbol on the downthrown block. Adapted from Winston 1989. 

 GLAC Geologic Resource Evaluation Report 37
Figure 14: Depositional environment of the Prichard-Altyn Formation atop the Neihart Quartzite which acts as a sediment source. 

Figure 15: Conceptual depositional environment of the Ravalli Group, showing basinward progression from the western continent to 

the near shore and deeper water settings. Adapted from Winston 1989. 

 NPS Geologic Resources Division 38 
Figure 16: Middle Belt Carbonate depositional facies. Modified from Winston 1989. 

 GLAC Geologic Resource Evaluation Report 39
Figure 17: Conceptual depositional environment of the Missoula Group up to the Garnet 

Range. Deeper water facies to the northwest. Adapted from Winston 1989. 

 NPS Geologic Resources Division 40 
Figure 18: Showing inferred Proterozoic structure of the Belt basin during Missoula Group deposition. Note numerous faults providing 

means for uplift south of the basin (sediment source area). “U” indicates the uplifted side of the fault, “D”, the downdropped side. 

Modified from Ackman 1988. 

Figure 19: Subaqueous (pillow layers) and subaerial (flows) phases of Purcell Lava enclosed by Snowslip Formation strata in Glacier 

National Park. The lower diagram depicts the vent facies found within the Purcell Lava locally. Modified from Raup et al. (1997). 

 GLAC Geologic Resource Evaluation Report 41
Figure 20: Deposition of the Kishenehn Formation as sediments continuously filled the graben valley of the North Fork of the Flathead 

River. 

 NPS Geologic Resources Division 42 
Figure 21: Geologic Time Scale; Red lines indicate major unconformities between eras. Included are major events in life history and 

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

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

 GLAC Geologic Resource Evaluation Report 43
 NPS Geologic Resources Division 44 

References 

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

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 GLAC Geologic Resource Evaluation Report 45

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 NPS Geologic Resources Division 46 

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White, B., 1984, Stromatolites and associated facies in 

shallowing- upward cycles from the middle 

Proterozoic Altyn formation of Glacier National Park, 

Montana. Precambrian Research, vol. 24, no. 1, pp. 1-

26. 

Willis, B., 1902, Stratigraphy and structure, Lewis and 

Livingston ranges, Montana. Geological Society of 

America Bulletin, pp.305- 352. 

Winston, D., 1986, An alluvial apron and playa- margin 

interpretation of Cu- and Ag- bearing sedimentary 

rocks, middle Proterozoic Belt Supergroup, Montana 

and Idaho. Program with Abstracts – Geological 

Association of Canada; Mineralogical Association of 

Canada; Canadian Geophysical Union, Joint Annual 

Meeting, vol. 11, pp. 146. 

Winston, D., 1989, Introduction to the Belt. In: 

Volcanism and plutonism of western North America; 

Volume 2, Middle Proterozoic Belt Supergroup, 

western Montana. Hanshaw, P.M., ed. American 

Geophysical Union, pp. 1- 6. 

Winston, D., 1989b, A Sedimentologic and tectonic 

interpretation of the Belt Supergroup. In: Volcanism 

and plutonism of western North America; Volume 2, 

Middle Proterozoic Belt Supergroup, western 

Montana. Hanshaw, P.M., ed. American Geophysical 

Union, pp. 1- 6. 

Winston, D., Lyons, T., 1997, Sedimentary cycles in the 

St. Regis, Empire and Helena Formations of the middle 

Proterozoic Belt Supergroup, northwestern Montana. 

In: Geologic guidebook to the Belt- Purcell 

Supergroup, Glacier National Park and vicinity, 

Montana and adjacent Canada; field trip guidebook 

for Belt symposium III. Link, P.K., ed., pp. 21- 51. 

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

Definition of members of Jurassic Entrada Sandstone 

in east- central Utah and west- central Colorado: 

American Association of Petroleum Geologists 

Bulletin, v. 46, no. 11, p. 2057- 2070. 

Yin, A., 1988, Geometry, kinematics, and a mechanical 

analysis of a strip of the Lewis Allochthon from Peril 

Peak to Bison Mountain, Glacier National Park, 

Montana. Dissertation, University of Southern 

California, Los Angeles, CA. 
Appendix A: Geologic Map Graphic 

Bedrock geologic units shown for graphic clarity, surficial geologic units and contacts 

are included on CD. For a detailed digital geologic map with all available coverages and 

cross sections produced by the GRE of the parks see included CD. 

The original maps digitized by NPS staff to create this product were: Carrara, P.E., 1990, Surficial geologic map of Glacier National 

Park, Montana, U.S. Geological Survey, I-1508-D, 1:100000 scale, and Whipple, James W., 1992, Geologic map of Glacier National Park, 

Montana, U.S. Geological Survey, I-1508-F, 1:100000 scale. For a detailed digital geologic map and cross sections, see included CD. 

 NPS Geologic Resources Division 48 
 GLAC Geologic Resource Evaluation Report 49

Appendix B: Scoping Summary 

The following excerpts are from the GRE Workshop Summary for Glacier National 

Park. Please contact Bruce Heise at the NPS Geologic Resources Division, Denver, CO 

for more information (Bruce_Heise@nps.gov, (303) 969- 2017). 

Executive Summary 

A geologic resources inventory workshop was held for 

Glacier NP (GLAC) on August 20- 22, 2002 to view and 

discuss the park’s geologic resources, to address the 

status of geologic mapping for compiling both paper and 

digital maps, and to assess resource management issues 

and needs. Cooperators from the NPS Geologic 

Resources Division (GRD), Natural Resources 

Information Division (NRID), NPS Glacier NP, the 

Montana Bureau of Mines and Technology, the 

Canadian Geological Survey, Parks Canada and other 

academics were present for the workshop. 

This involved a field trip to view the geology of the 

Glacier NP area and a scoping session to present 

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

program, the Geologic Resources Division, and the ongoing Geologic Resources Evaluation (GRE). Round 

table discussions involving geologic issues for Glacier NP 

included interpretation, the status of geologic mapping 

efforts, sources of available data, and action items 

generated from this meeting. 

Currently, some of the biggest geologic issues the park 

faces are retreat of its glaciers (it’s estimated that they 

will all be melted by 2030) and landslides and geologic 

hazards along Going to the Sun Road. 

Overview of Geologic Resources Evaluation 

The NPS GRE has the following goals: 

• to assemble a bibliography of associated geological 

resources for NPS units with significant natural 

resources (“GRBIB”) to compile and evaluate a list of 

existing geologic maps for each unit, 

• to conduct a scoping session for each park, 

• to develop digital geologic map products, and 

• to complete a geological report that synthesizes much 

of the existing geologic knowledge about each park. 

It is stressed that the emphasis of the inventory is not to 

routinely initiate new geologic mapping projects, but to 

aggregate existing "baseline" information and identify 

where serious geologic data needs and issues exist in the 

National Park System. In cases where map coverage is 

nearly complete (ex. 4 of 5 quadrangles for Park “X”) or 

maps simply do not exist, then funding may be available 

for geologic mapping. 

After introductions by the participants, Tim Connors 

and Bruce Heise (both NPS- GRD) presented overviews 

of the Geologic Resources Division, the NPS I&M 

Program, the status of the natural resource inventories, 

and the GRE in particular. 

They also presented a demonstration of some of the 

main features of the GRE digital geologic database. This 

has become the prototype for the NPS digital geologic 

map model as it reproduces all aspects of a paper map 

(i.e. it incorporates the map notes, cross sections, legend 

etc.) with the added benefit of being geospatially 

referenced. It is displayed in ESRI ArcView shape files 

and features a built- in Microsoft Windows help file 

system to identify the map units. It can also display 

scanned JPG or GIF images of the geologic cross sections 

supplied with the paper "analog" map. Geologic cross 

section lines (ex. A- A') are subsequently digitized as a 

line coverage and are hyperlinks to the scanned images. 

Tim further demonstrated the developing NPS Theme 

Manager for adding GIS coverage’s into projects "onthe- fly". With this functional browser, numerous NPS 

themes can be added to an ArcView project with relative 

ease. Such themes might include geology, paleontology, 

hypsography (topographic contours), vegetation, soils, 

etc. 

At the scoping session, individual Microsoft Word 

Documents of Geologic Bibliographies for GLAC were 

distributed. 

The sources for this compiled information are as follows: 

• AGI (American Geological Institute) GeoRef 

• USGS GeoIndex 

• ProCite information taken from specific park libraries 

These bibliographic compilations were validated by GRE 

staff to eliminate duplicate citations and typographical 

errors, as well as to check for applicability to the specific 

park. After validation, they become part of a Microsoft 

Access database parsed into columns based on park, 

author, year of publication, title, publisher, publication 

number, and a miscellaneous column for notes. 

From the Access database, they are exported as 

Microsoft Word Documents for easier readability, and 

eventually turned into PDF documents. 
 NPS Geologic Resources Division 50 

Geologic Mapping 

After the bibliographies were assembled, a separate 

search was made for any existing surficial and bedrock 

geologic maps for GLAC. The bounding coordinates for 

each map were noted and entered into a GIS to assemble 

an index geologic map. Separate coverage’s were 

developed based on scales (1:24,000, 1:100,000, etc.) 

available for the specific park. Numerous geologic maps 

at varying scales and vintages cover the area. Index maps 

were distributed to each workshop participant during 

the scoping session. 

At present, the USGS has produced numerous 

publications on the Geology of Glacier NP. Their I- 1508 

map series has both bedrock (Whipple, J.W., 1992, 

Geologic map of Glacier National Park, Montana, US 

Geological Survey, I- 1508- F, 1:100000 scale) and surficial 

(Carrara, P.E., 1990, Surficial geologic map of Glacier 

National Park, Montana, US Geological Survey, I- 1508-

D, 1:100000 scale) geologic paper maps covering the 

current park boundary. 

The general consensus of those cooperators at the 

meeting was that these existing maps were quite 

adequate for resource management purposes. 

Suggested improvements included upgrading a layer 

showing geologic hazards and landslides, as well as 

further refinement of a few surficial units. 

Digital Geologic Map coverage 

The GLAC GIS staff has obtained completed digital 

geologic coverages for the two maps mentioned above 

along with FGDC compliant metadata. Tim Connors 

previewed this data to the group and Richard Menicke 

also showed an image of the geology draped over a 

shaded relief map to illustrate the bedrock control on the 

topography.Apparently, these maps were digitized out of 

North Carolina State University. They captured geologic 

polygons on both maps, but excluded other coverages 

from the bedrock map such as folds, faults, contact line 

types, cross sections, etc. It will be likely that GRE staff 

will have to re- digitize these maps to capture this other 

necessary attribute data, but we will try to work with the 

existing linework and match it up to the original 

attributes on paper as best as possible. 

These coverages are currently downloadable from: 

http://www.nps.gov/gis/available_data 

Other desired GIS data 

Soils maps are also of interest to GLAC staff. Tim 

Connors will check with Pete Biggam (NPS- Soil 

Scientist) on the status of soils mapping for the area; will 

require more follow- up. 

Miscellaneous

Another bibliography was distributed by David Butler to 

some meeting attendees; needs to be compared and 

synthesized into our GRBIB 
 GLAC Geologic Resource Evaluation Report 51

List of Scoping Meeting attendees with contact information 

NAME AFFILIATION TITLE PHONE E- MAIL 

Berger Tony University of Victoria, 

BC Geologist 250- 480- 0840 aberger@uvic.ca 

Biggam Pete NPS, Natural Resources 

Information Division soil scientist (303) 987- 6948 Pete_Biggam@nps.gov 

Butler David Southwest Texas State 

University Geologist 512- 245- 7977 db25@swt.edu 

Campbell Walt USGS IM coordinator, 

Rocky Mt. Network 970- 226- 9487 walton.campbellj@att.net 

Carolin Tara NPS- GLAC ecologist 406- 888- 7919 tara_carolin@nps.gov 

Connors Tim NPS, Geologic 

Resources Division geologist (303) 969- 2093 Tim_Connors@nps.gov 

Covington Sid NPS, Geologic 

Resources Division geologist (303) 969- 2154 Sid_Covington@nps.gov 

Deal Ed Montana Bureau of 

Mines and Geology geologist edeal@mtech.edu 

Dolan Bill NPS- Waterton Lakes chief park warden 403- 859- 5118 bill.dolan@pc.gc.ca 

Fagre Dan USGS ecologist 406- 888- 7922 dan_fagre@usgs.gov 

Gonzalez Ignacio University of 

Saskatchewan geologist 306- 966- 8591 iag140@mail.usask.ca 

Graham John 

Colorado State 

University, GRE report 

writer 

geologist 970- 225- 6333 jpgraham250@msn.com 

Gregson Joe NPS, Natural Resources 

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

Heise Bruce NPS, Geologic 

Resources Division geologist (303) 969- 2017 Bruce_Heise@nps.gov 

Higgins Bob NPS, Geologic 

Resources Division geologist (303) 969- 2018 Bob_Higgins@nps.gov 

KellerLynn Katie geologist 970- 586- 7243 katie.david@prodigy.net 

Malanson George University of Iowa ecologist 319- 335- 0540 george- malanson@uiowa.edu 

Marnell Leo NPS- GLAC biologist 406- 888- 7995 leo_marnell@nps.gov 

Martin Larry NPS- WRD hydrogeologist 970- 225- 3515 larry_martin@nps.gov 

McNeil Ron University of Lethbridge soil scientist 403- 320- 5099 landys@telusplanet.net 

Menicke Richard NPS- GLAC GIS 406- 888- 7918 richard_menicke@nps.gov 

Michels Bill NPS- GLAC natural resources bill_michels@nps.gov 

Ozaki Vicki NPS- REDW geologist 707- 825- 5142 vicki_ozaki@nps.gov 

Pellatt Marlow Parks Canada paleontologist 604- 666- 2556 marlow_pellatt@pc.gc.ca 

Potter Jack NPS- GLAC chief ranger 406- 888- 7821 jack_potter@nps.gov 

Relyea Scott Flathead Lake Biological 

Station research coordinator 406- 982- 3301, ext. 222 srelyea@selway.umt.edu 

Schumann Randy USGS geologist 303- 236- 5344 rschumann@usgs.gov 

Smith Cyndi Parks Canada biologist 403- 859- 5137 cyndi.smith@pc.gc.ca 

Tonnessen Kathy University of Montana research coordinator kat@forestry.umt.edu 

Welch David Parks Canada 819- 994- 5532 david.welch@pc.gc.ca 

Wood Jim NPS, Geologic 

Resources Division physical scientist (303) 969- 2149 Jim_F._Wood@nps.gov 
 NPS Geologic Resources Division 52 

Appendix C: Geoindicators Scoping Report 

The following are excerpts of the Geoindicators Scoping Report for Glaciers National 

Park, compiled by Katie KellerLynn, 2002. A complete version of the report may be 

found at the following web address: 

http://www2.nature.nps.gov/grd/geology/monitoring/ib4/index.htm. 

Introduction 

The National Park Service, Parks Canada, U.S. 

Geological Survey, and International Union of 

Geological Sciences sponsored a geoindicators scoping 

meeting in Waterton- Glacier International Peace Park in 

West Glacier, Montana on August 20- 22, 2002. 

Purpose of meeting 

The purpose of the meeting was threefold: (1) to identify 

significant geological processes and features that are part 

of the park’s ecosystem, (2) to evaluate human influences 

on those processes and features, and (3) to provide 

recommendations for studies to support resource 

management decisions, geologic inventory and 

monitoring projects, and research to fill data gaps. The 

scoping meeting was designed to use the participants’ 

expertise and institutional knowledge and build on the 

synergy of the participants through field observations, 

group discussion, and the exchange of ideas. 

Government Performance and Results Act (GRPA) Goal Ib4 

This meeting satisfies the requirements of the GPRA 

Goal Ib4, which is a knowledge- based goal that states, 

“Geological processes in 53 parks [20% of 265 parks] are 

inventoried and human influences that affect those 

processes are identified.” The goal was designed to 

improve park managers’ capabilities to make informed, 

science- based decisions with regards to geologic 

resources. It is the intention of the goal to be the first step 

in a process that will eventually lead to the mitigation or 

elimination of human activities that severely impact 

geologic processes, harm geologic features, or cause 

critical imbalance in the ecosystem. 

Because GPRA Goal Ib4 inventories only a sampling of 

parks, information gathered at Waterton- Glacier 

International Peace Park may be used to represent other 

parks with similar resources or human influences on 

those resources, especially when findings are evaluated 

for Servicewide implications. 

Geoindicators background information 

A Working Group of the International Union of 

Geological Sciences developed geoindicators as an 

approach for identifying rapid changes in the natural 

environment. 

The National Park Service uses geoindicators during 

scoping meetings as a tool to fulfill GPRA Goal Ib4. 

Geoindicators are measurable, quantifiable tools for 

assessing rapid changes in earth system processes. 

Geoindicators evaluate 27 earth system processes and 

phenomena that may undergo significant change in 

magnitude, frequency, trend, or rates over periods of 100 

years or less and may be affected by human actions. 

Geoindicators are used as a framework to guide the 

discussion and field observations during scoping 

meetings. The geoindicators scoping process for the 

National Park Service was developed to help determine 

the studies necessary to answer management questions 

about what is happening to the environment, why it is 

happening, and whether it is significant. 

The health and stability of an ecosystem is evaluated 

during the geoindicators scoping process. The geologic 

resources of a park—soils, caves, streams, springs, 

beaches, volcanoes, etc.—provide the physical 

foundation required to sustain the biological system. 

Geological processes create topographic highs and lows; 

affect water and soil chemistries; influence soil fertility, 

hillslope stability, and the flow styles of surface water 

and groundwater. These factors, in turn, determine 

where and when biological processes occur, such as the 

timing of species reproduction, the distribution of 

habitats, the productivity and type of vegetation, and the 

response of ecosystems to human impacts. 

Park Selection 

The idea to hold a geoindicators scoping meeting in 

Waterton- Glacier International Peace Park developed at 

the “International Workshop on Geoindicators for 

Ecosystem Monitoring in Parks and Protected Areas” in 

Gros Morne National Park, Newfoundland, Canada on 

September 10- 14, 2001. The desire for continued 

collaboration between the National Park Service and 

Parks Canada, in particular, made hosting a meeting in 

the Peace Park an ideal location. In addition the park was 

selected for is its unique geologic resources, park setting, 

and human use. 

It is important to note that 95% of Glacier National Park 

is proposed wilderness, and over 80% of Waterton Lakes 

National Park has been recommended for wilderness 

declaration. 
 GLAC Geologic Resource Evaluation Report 53

The remaining small percentage of land—that is, the 

developed corridors along the Going- to- the- Sun Road, 

all roads and part of Blakiston Fan in Waterton Lakes, 

and established townsites—is where park staff focuses 

much of their energy and resources on managing the 

effects of human activities. 

Summary of Results 

During the scoping meeting, geoindicators appropriate 

to Waterton- Glacier International Peace Park were 

addressed. Of the 27 geoindicators, 21 were recognized as 

on- going processes in the park. The issues surrounding 

each geoindicator were identified, and participants rated 

the geoindicator with respect to the importance to the 

ecosystem and human influence (Geoindicator table). 

The park staff rated the significance for park 

management. A compilation of the notes taken during 

the scoping session and field trip are included with the 

report. These notes highlight additional information 

regarding geoindicators that may be useful to park 

managers. 

Significant geoindicators 

The following is a summary of the results for the 11 

geoindicators that rated the highest in all three 

categories, as well as the recommendations for these 

geoindicators that were proposed during the meeting. 

Snow Avalanches 

Snow avalanches are ubiquitous throughout the park; 

they are a major landscape disturbance that shapes the 

park’s ecosystem. Snow- avalanche tracks have great 

importance to the ecosystem; they are: productive 

environments, key habitat that serve as migration paths 

for grizzly and mountain goats, fuel breaks for fire, 

conduits for carbon and sediment from higher to lower 

elevations, including streams. 

Human impacts 

Snow avalanches are a public safety issue, particularly for 

winter backcountry users. Park staff spends a 

considerable amount of time forecasting snow 

avalanches. Snow- avalanche hazards are a factor in 

determining the opening date of the Going- to- the- Sun 

Road and may influence the clearing of Akamina 

Parkway through the winter months. Snow avalanches 

are also significant to management as creators of wildlife 

habitat, particularly grizzly bear, a threatened species in 

the United States. 

Soil and sediment erosion 

Soil erosion is part of the natural system in WatertonGlacier International Peace Park. Concerns arise for 

ecosystem health when effects of soil and sediment 

erosion are human- caused and detrimental, such as soil 

erosion resulting from poor design and construction of 

facilities and infrastructure. 

Estimates of soil erosion are essential to issues of land 

and water management and to ecosystem health and 

function. 

Human impacts 

Management issues include construction projects that 

result in pulses of sediment carried downstream. For 

example, sediment resulting from the construction of the 

Going- to- the- Sun Road can be seen in the sediment 

column in McDonald Creek and in Lake McDonald. 

Reclamation of soils degraded by human actions is of 

high management significance. 

Soil quality 

Concerns regarding soil quality in the park include: 

breakdown of soil structure, loss of function, harm to 

soil biota, regional acid deposition, nitrate deposition 

(from urban pollution and fertilizers), and airbornemercury deposition from power plant emissions. 

Human Impacts 

Park managers spend time and resources dealing with 

soil quality and restoration issues, particularly because of 

the human impacts in developed areas, such as social 

trails and trail maintenance; borrow pits (historically 

became garbage pits, which attracted bears); horse use 

(primarily a legacy issue); popular lakes with multiple 

entry points; locating and constructing park facilities, 

e.g., Logan Pass Visitor Center; depletion of soils along 

roadsides, which causes greater amount of noxious 

weeds; plowing which causes soil compaction and 

depletion along roadsides; and salt and petrochemical 

runoff from roads. 

Streamflow 

Streamflow affects riparian zones and wetlands in the 

park. Streamflow directly reflects climatic variation. 

Stream systems play a key role in the regulation and 

maintenance of biodiversity. Changes in streams and 

streamflow are indicators of changes in basin dynamics 

and land use. 

Human impacts 

The potential for human impact to stream sediment 

erosion, storage, and load is great. These impacts include 

building parking lots and structures in or near channels, 

building structures (e.g., culverts and bridges) in 

floodplains, grazing in uplands and stream channels, 

roads and trails up streambeds, introduction of exotic 

species, and impacts from flow regulation and diversion. 

Wetlands extent, structure, and hydrology 

Waterton- Glacier International Peace Park has many 

different kinds of wetlands, including fens, bogs, 

nutrified lakes, and swamps. Glacial retreat has 

influenced wetlands. Wetlands in the park are extremely 

dynamic, and nearly all species of wildlife rely on 

wetlands in one way or another. 
 NPS Geologic Resources Division 54 

Human impacts 

In the United States, law mandates that land managers 

always consider wetlands in management decisions. In 

Canada, it is not legally mandated, but managers 

recognize the significance of wetlands and the potential 

impact of human uses on them. 

Surface water quality 

In addition to being a public health issue, surface water 

quality is an essential component of ecosystem health. All 

forms of life depend on clean water. Waterton- Glacier 

International Peace Park sits at the headwaters of the 

Waterton and Belly rivers. Since water quality exceeds 

standards, the surface water quality geoindicator is a 

good indicator of change, and minor changes are easily 

detectable. 

Human impacts 

Human practices that affect surface water quality include 

herbicide and pesticide applications, e.g., for eradicating 

knapweed. Locations of campgrounds, lodges, roads, 

and other facilities and infrastructure in sensitive 

floodplain and stream delta areas have produced runoff 

that impacts fragile invertebrate communities in streams. 

Localized situations, such as boating on St. Mary Lake 

and Upper and Middle Waterton Lake, have resulted in 

diesel fuel spills. For instance, during a high wind event, a 

barge capsized on St. Mary Lake spilling 50 gallons of 

diesel fuel. 

Wetlands extent, structure, and hydrology 

Wetlands are important ecosystems because they 

stabilize streambanks, act as filters to improve water 

quality, attenuate floodwaters, enhance biodiversity 

(important habitat for amphibians, reptiles, birds, and 

Threatened and Endangered Species), are highly 

productive in terms of biomass and nutrient 

productivity, and are valuable water sources for wildlife 

and recreationists. 

Human impacts 

The potential for human impacts on wetlands is great. 

These impacts include building parking lots and 

structures in or near channels, building structures (e.g., 

culverts and bridges) in floodplains, grazing in uplands 

and stream channels, roads and trails up streambeds, 

introduction of exotic species, and impacts from flow 

regulation and diversion. In addition, agricultural 

activities and past extirpation of beaver have affected 

wetlands. 

Groundwater quality 

Management concerns revolve around human influences 

on groundwater quality, such as the effects of sewage 

treatment, inholders’ septic systems, salt application to 

roads (in Waterton Lakes National Park only), road 

runoff, pesticides, gasoline leaks from underground 

storage tanks (e.g., in Apgar), and service stations in the 

park. 

Slope failure 

Slumping along Many Glacier Road is a continuing 

maintenance issue. Not only does the road undercut the 

slope, but water from adjacent Lake Sherburne saturates 

and weakens the slope. Slumping along Blakiston Creek 

is a concern along parts of the Red Rock Parkway. Also, a 

pending question with respect to climate change and 

slope failure is whether increased rainfall events will 

cause more landslides. 

Sediment sequence and composition 

One geoindicator in particular was singled out and 

warrants mention. Unlike the other geoindicators, 

sediment sequence and composition is not a geological 

process, but rather a tool with great significance for 

enhancing the information base of the park’s ecosystem, 

identifying human influences on the ecosystem, and 

providing data for resource management decisions and 

planning. It provides the necessary background 

information and a past context of both natural processes 

and human activities. The chemical, physical, and 

biological character of aquatic sediments can provide a 

finely resolvable record of environmental change, in 

which natural events may be clearly distinguished from 

human inputs. 

Soil and sediment erosion and deposition by water 

During the discussion of this geoindicator, participants 

chose to focus on water transport and deposition, 

therefore the words, “and deposition by water” were 

added to this geoindicator. Transport and/or loss of soil 

may result in degradation of soil quality (see Soil quality 

geoindicator). 
 GLAC Geologic Resource Evaluation Report 55

Summary of Recommendations 

The following summary of recommendations lists ideas 

that were discussed during the August 20- 22, 2002 

scoping meeting held in Waterton- Glacier International 

Peace Park. The summary includes recommendations for 

inventory and monitoring, as well as research. 

Recommendations are not listed in any order of priority. 

Inventory and monitor wetlands 

There are many different kinds of wetlands in the park: 

fens, bogs, nutrified lakes, swamps, etc. Park managers 

need more accurate and consistent descriptions of these 

wetlands. The first step toward an inventory would be to 

validate the classification of the Fish and Wildlife Service 

and refine its delineation. Once sites have been 

identified, historical aerial photographs (in sequence) 

followed by ground- truthing could be used to verify and 

characterize the sites. The inventory could be 

supplemented by remote sensing, although remote 

sensing can be expensive and the tree canopy may hide 

some wetlands. 

Monitoring is needed to determine future changes in 

wetlands. If significant changes are detected, then 

research will be required to determine the cause(s). 

Monitoring of wetlands could be multi- faceted, 

including vascular plants and water chemistry. Wetland 

studies suggest opportunities for integrated research and 

collaboration. Paleoecological methods can be used to 

date peat and/or sediments to determine the 

hydrological succession of wetlands. 

Contacts 

Marlow Pellatt, 604- 666- 2556, 

Marlow_Pellatt@pc.gc.ca 

Randy Schumann, 303- 236- 5344, rschumann@usgs.gov 

Kathy Tonnesson, 406- 243- 4449, kat@forestry.umt.edu 

Provide groundwater data to Montana Bureau of Mines and 

Geology 

The Montana Bureau of Mines and Geology has a 

statewide groundwater program. Park staff is welcome to 

share/submit data to Montana Bureau of Mines and 

Geology for entry into the Bureau’s Ground- Water 

Information Center (GWIC) database. Information in 

the database is available via the Bureau’s GWIC Web site 

at http://mbmggwic.mtech.edu/. High mountain areas, 

such as those in the park, typically do not have many 

wells, so information for these areas is limited. 

Contact 

Tom Patton, Manager, Ground Water Assessment 

Program, 406- 496- 4153, tpatton@mtech.edu or directly 

access the database 

Verify soil survey 

Both Waterton Lakes National Park and Glacier 

National Park have soil surveys but need a consistent 

interpretation of soil classification, derivative products, 

and sampling to characterize locales (e.g., along road 

corridors). 

Contacts 

Pete Biggam, 303- 987- 6948, pete_biggam@nps.gov 

Barry Dutton, 406- 721- 0354, info@landandwater.net 

Ron McNeil, 403- 320- 0407, landys@telusplanet.net 

Monitor change in soil carbon storage 

Participants recommend that park managers monitor 

changes in carbon storage once every 5 to 10 years, by 

measuring the organic carbon in surface soil layer(s) 

through sampling and then resampling at the same 

locations. The use of Douglas fir, which is very sensitive 

to CO2

, can be used as an indicator species and as an 

early warning of detrimental changes in the ecosystem. 

See Appendix I for corresponding proposal. 

Contacts 

Pete Biggam, 303- 987- 6948, pete_biggam@nps.gov 

Ron McNeil, 403- 320- 0407, landys@telusplanet.net 

Randy Schumann, 303- 236- 5344, rschumann@usgs.gov 

References 

Thompson, R.S., Hostetler, S.W., Bartlein, P.J., and 

Anderson, K.H., 1998, A strategy for assessing potential 

future changes in climate, hydrology, and vegetation in 

the western United States: U.S. Geological Survey 

Circular 1153, 20 p. 

White, J.D., Running, S.W., Thornton, P.E., Keane, R.E., 

Ryan, K.C., Fagre, D.B., and Key, C.H., 1998, Assessing 

simulated ecosystem processes for climate variability 

at Glacier National Park, USA: Ecological 

Applications, v. 8, no. 3, p. 805- 823. 

White, J.D. and Running, S.W., 1994, Testing scaledependent assumptions in regional ecosystem 

simulations: Journal of Vegetation Science, v. 5, no. 5, 

p. 687- 702. 

Sources of information on the Web 

http://www.forestry.umt.edu/ntsg/ 

Web site of work done by Steve Running on carbon and 

climate change 
 NPS Geologic Resources Division 56 

Monitor streamflow and seek secure funding 

The park needs basic monitoring of streamflow in the 

interior of park. Secure funding is needed. Participants 

recommend that park managers pursue a partnership 

with U.S. Geological Survey. The NPS Water Resources 

Division can assist with defining needs including 

monitoring locations, number of monitoring stations 

needed, and cost. Redwood National and State Park has 

an established partnership with U.S. Geological Survey 

for monitoring gauging stations and could serve as a 

model. 

Contacts 

Larry Martin, 970- 225- 3515, larry_martin@nps.gov 

Vicki Ozaki, 707- 825- 5142, Vicki_Ozaki@nps.gov 

Randy Schumann, 303- 236- 5344, rschumann@usgs.gov 

Repeat survey of lakes 

A survey of baseline water quality data for lakes needs to 

be repeated. 

Contact 

Dan Fagre, 406- 888- 7922, dan_fagre@usgs.gov 

Use aerial photography to document changes and features 

in the landscape 

Use repeat aerial photography to document the change 

in snow- avalanche paths (extent, location) over time and 

document features caused by slope failure. Scan past 

aerial photographs, contained in park archives, to use for 

analysis and interpretation of future slope failure in a 

digital format. 

Add seismic station(s) within park boundary 

A seismic monitoring program run by Montana Bureau 

of Mines and Geology (MBMG) currently has 34 

stations, mostly in the western part of Montana. 

Additionally, they receive data from stations in bordering 

areas, including a station in Waterton Lakes National 

Park. The latter, in conjunction with other stations that 

they operate, allows MBMG to locate earthquakes in the 

vicinity of the park, but resolution is poor and the 

smaller earthquakes go undetected. Much better 

detection and resolution could be obtained with 1 or 2 

additional stations inside the park. MBMG data feed into 

the national U.S. Geological Survey system in Colorado. 

Detected quakes are automatically analyzed and 

information is posted on MBMG’s Web site within 

minutes: http://mbmgquake.mtech.edu/. Each station 

costs $15,000- $25,000 plus nominal upkeep of the 

station. 

Contact 

Mike Stickney, Manager, Earthquake Studies Office, 

406- 496- 4332, mstickney@mtech.edu 

Monitor dust storms as part of air quality monitoring 

Dust storms may be a factor in the decline of air quality 

and visibility in Waterton- Glacier International Peace 

Park. If air quality declines, an analysis of particles (size 

and composition) would help determine source area(s). 

It would assist in answering the question, What impact 

are western Washington’s agricultural practices having 

on the park? This type of data collection is being 

conducted in Olympic National Park. 

Inventory cave resources 

Park managers in Glacier National Park have basic 

information, e.g., number and location, about the 

significant caves within its boundaries, but do not have 

information on cave resources or whether conditions 

within the caves are changing. Local cavers could be used 

to perform an inventory, specifically there is a “grotto” 

(cavers group of the National Speleological Society) in 

Missoula. Such groups have the necessary expertise to 

perform such an inventory and have been known to 

provide this service for free. 

Contact 

Ron Kerbo, Cave Specialist, NPS Geologic Resources 

Division, 303- 969- 2097, ron_kerbo@nps.gov 

Study wind erosion on an ecosystem-wide scale 

How significant overall is the wind as an erosion- causing 

agent? What ecosystem- wide impact does wind erosion 

have? In order to answer these questions, wind erosion 

would need to be identified and separated from impacts 

caused by other forms of erosion, including humancaused erosion. Once these impacts are identified, sitespecific inventories could be performed using repeat 

photography and Global Positioning System (GPS) 

surveys. 

Inventory stream channels 

Natural Resources Conservation Service (NRCS) in 

Montana is photographing stream reaches using digital 

video camcorder (with GPS and Red Hen software 

systems). The effort was initiated for fisheries and 

riparian management, but information could be 

extrapolated and used for stream channel morphology 

and stream sediment storage and load. 

Contact 

Tom Pick, tpick@mt.nrcs.usda.gov 
 GLAC Geologic Resource Evaluation Report 57

Monitor mass balance of glaciers 

Knowledge of seasonal mass balances (e.g., summer and 

winter) would shed light on glacier fluctuations in 

Waterton- Glacier International Peace Park. For 

example, it would help answer questions such as: Is 

glacier contraction caused primarily by less nourishment 

in winter or by more melt in summer? Monitoring of 

mass balance would also assist in the interpretation of 

streamflow records. 

Having a glacier mass balance site at the longitude of 

Waterton- Glacier International Peace Park would make 

an excellent contribution to the Global Terrestrial 

Network- Glacier (GTN- G) of World Meteorological 

Organization’s (WMO) Global Climate Observing 

Network (GCOS). A site this far south may provide a 

good analog for what could be expected further north in 

the Canadian Rocky Mountains over the next century 

with respect to global climate change. In addition, 

Waterton- Glacier International Peace Park could be 

part of the Global Terrestrial Observing Systems 

(GTOS), Terrestrial Monitoring System (TEMS). 

Contact 

Michael N. Demuth, 613- 996- 0235, 

mdemuth@nrcan.gc.ca 

Create “lake ice model” 

Information about lake ice (annual first thaw and first 

freeze) would provide data regarding climate change and 

serve as an early- warning indicator of change. It is also 

significant for the arrival of migrating waterfowl. 

Creating a “lake ice model” could be done using existing 

meteorological data and information from past issues of 

the Hungry Horse newspaper, which records years that 

the large lakes in the area have frozen over. 

Contact 

Dan Fagre, 406- 888- 7922, dan_fagre@usgs.gov 

Determine whether small lakes are being filled in with 

sediment 

Radiometric dating techniques could be used to address 

the question of whether the small lakes in the park are 

being filled in with sediment. 

Contact 

Marlow Pellatt, 604- 666- 2556, 

Marlow_Pellatt@pc.gc.ca 

Update surficial geologic map 

The surficial geologic map of Glacier National Park 

needs to be updated. The current map does not show all 

of the locations of snow- avalanche paths, all the areas of 

landsliding, or all the lake deposits. A coordinated 

mapping effort between Glacier National Park and 

Waterton Lakes National Park is recommended for 

consistency across the Canadian- United States 

boundary. 

Once this map is updated, a derivative map that shows 

landslide- hazard areas could be produced that would 

provide needed information to park managers. 

Reference 

Carrara, P.E., 1990, Surficial geologic map of Glacier 

National Park, Montana: U.S. Geological Survey 

Miscellaneous Investigation Series, No. I- 1508- D, 

1:100,000. 

Conduct snow-avalanche studies 

The significance of snow avalanches on the park’s 

ecosystem and for park management was discussed 

previously. Having more information regarding the 

frequency, cycles, and locations of snow avalanches 

would be useful to park managers. Park managers are 

encouraged to seek funding through the NPS 

Geoscientist- in- the- Parks program. Possible projects 

include: 

Develop frequency of event analysis and historical 

record (e.g., from Waterton townsite record). Some 

attempt as this has been made using tree rings. 

Compare east and west side cycles of snow avalanches. 

Establish landscape- level disturbance agent and look at 

drivers. Check against Pacific Decadal Oscillation 

climatic variations and see if it is tied to the response of 

snow avalanches. 

Answer questions such as, Does snowfall level influence 

frequency? How much woody debris do snow 

avalanches deliver to the Highway 2 corridor? What is 

the relative amount of woody debris vs. rock material in 

snow avalanches? 

Contacts 

David Butler, 512- 245- 7977, db25@swt.edu 

George Malanson, 319- 335- 0504, georgemalanson@uiowa.edu 

Judy Geniac, Manager, Geoscientist- in- the- Parks, 303-

969- 2015, judy_geniac@nps.gov 

Answer research questions regarding slope failure 

What is the relative importance of mass movement vs. 

stream transport? Will an increase in rain events cause 

more landslides? 

Reference 

Rapp, A., 1960, Recent development of mountain slopes 

in Karkevagge and surrounding northern Scandinavia: 

Geografisk Annaler, v. 42, p. 73- 200. 
 NPS Geologic Resources Division 58 

Answer research questions regarding wetlands 

What is the effect of fire on wetlands? Where and to what 

extent do wetlands exist from year to year? What are past 

impacts of glacier fluctuations on wetlands? 

References 

Hansen, H.P., 1948, Postglacial forests of the Glacier 

National Park region: Ecology, v. 29, p. 146- 152. 

Elias, S.A., 1988, Climatic significance of Late Pleistocene 

insect fossils from Marias Pass, Montana: Canadian 

Journal of Earth Sciences, v. 25, p. 922- 926. 

Carrara, P.E., 1995, A 12,000 year radiocarbon date of 

deglaciation from the Continental Divide of 

northwestern Montana: Canadian Journal of Earth 

Sciences, v. 32, p. 1203- 1307. 

Carrara, P.E., 1989, Late Quaternary glacial and 

vegetative history of the Glacier National Park region, 

Montana: U. S. Geological Survey Bulletin 1902, 64 p. 

Other recommendations 

Recommend that the Vital Signs Network hire a soil 

scientist. Many of the natural resources staff members in 

Glacier National Park have strong backgrounds in plant 

ecology and work with the Natural Resource 

Conservation Service (NRCS). However, there is a need 

for expertise in soil science. Hiring a soil scientist would 

be extremely difficult at the park- level because of 

budgetary constraints, so the participants suggest that 

park staff encourage the Rocky Mountain Vital Signs 

Network to hire a soil scientist that could be shared with 

the other parks in the network. 

List of Participants 

Glacier National Park 

Tara Carolin, Ecologist 

Leo Marnell, Senior Scientist 

Richard Menicke, Geographer 

Bill Michels, Resource Management Specialist 

Jack Potter, Assistant Chief Ranger 

Waterton Lakes National Park 

Bill Dolan, Chief Park Warden 

Cyndi Smith, Conservation Biologist 

National Park Service 

Pete Biggam, Natural Resources Information Division, 

Lakewood, Colorado 

Walt Campbell, Rocky Mountain Inventory and 

Monitoring Network, Ft. Collins, Colorado 

Tim Connors, Geologic Resources Division, Lakewood, 

Colorado 

Sid Covington, Geologic Resources Division, Lakewood, 

Colorado 

Joe Gregson, Natural Resources Information Division, 

Ft. Collins, Colorado 

Bruce Heise, Geologic Resources Division, Lakewood, 

Colorado 

Bob Higgins, Geologic Resources Division, Lakewood, 

Colorado 

Larry Martin, Water Resource Division, Ft. Collins, 

Colorado 

Vicki Ozaki, Redwood National and State Parks, Arcata, 

California 

Jim Wood, Geologic Resources Division, Lakewood, 

Colorado 

Parks Canada 

Marlow Pellatt, Western Canada Service Center, 

Vancouver, British Columbia 

David Welch, National Parks Directorate, Ottawa, 

Ontario- Gatineau, Québec 

U.S. Geological Survey 

Dan Fagre, USGS Science Center, Glacier National Park 

Randy Schumann, Denver, Colorado 

Other Participants 

Tony Berger, International Union of Geological 

Sciences, Victoria, British Columbia 

David Butler, Southwest Texas State University, San 

Mancos, Texas 

Ed Deal, Montana Bureau of Mines and Geology, Butte, 

Montana 

Michael N. Demuth, Geological Survey of Canada, 

Ottawa, Ontario (report review only) 

Ignacio J. Gonzalez, University of Saskatchewan, 

Saskatoon, Saskatchewan 

John Graham, Colorado State University, Ft. Collins, 

Colorado 

Katie KellerLynn, NPS Contractor, Estes Park, Colorado 

George Malanson, University of Iowa, Iowa City, Iowa 

Ron McNeil, LandWise Inc., Lethbridge, Alberta 

Scott Relyea, Flathead Lake Biological Station, Polson, 

Montana 

Kathy Tonnessen, University of Montana (CESU), 

Missoula, Montana 
 GLAC Geologic Resource Evaluation Report 59

Geoindicator table for Glacier National Park. 

GEOINDICATOR Importance to park 

ecosystem 

Human influence on 

geology 

Significance for natural 

resource management 

AEOLIAN 

Dust storm magnitude, duration, and frequency 2 1 1 

Wind erosion (transport and deposition) 3 3 4 

GLACIAL & PERIGLACIAL 

Frozen ground activity 2 1 1 

Glacier fluctuations 4 N/A 2 

GROUNDWATER 

Groundwater chemistry in the unsaturated zone 1 1 (3 locally) 3 

Groundwater quality 4 1 (5 locally) 3 

Groundwater level 4 1 2 

SURFACE WATER 

Lake levels and salinity (including lake ice) 2 1 3 

Stream channel morphology 4 2 (4 locally) 4 

Stream sediment storage and load 4 2 (4 locally) 4 

Streamflow 5 1 3 

Surface water quality 5 1 (5 locally) 3 

Wetlands extent, structure, hydrology 5 2 (4 locally) 5 

SOILS 

Soil quality 5 2 (4 locally) 5 

Soil and sediment erosion 5 2 (4 locally) 5 

TECTONICS & GRAVITY 

Seismicity 1 N/A 1 

Slope failure 4 1 5 

Snow avalanches 5 1 5 

OTHER 

Karst activity 1 U 2 

*Sediment sequence and composition 5* 5* 5* 

Subsurface temperature regime U U U 

N/A - Not Applicable 

1 - LOW or no substantial influence on, or utility for 

3 - MODERATELY influenced by, or has some 

utility for 

5 - HIGHLY influenced by, or with important utility 

for 

U - Unknown; may require study to determine 

applicability 

*Sediment sequences and composition is a tool with great significance for 

enhancing the information base of the park’s ecosystem, identifying human 

influences on the ecosystem, and providing data for management decisions 

and planning. 

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. 

Glacier National Park 

Geologic Resource Evaluation Report 

Natural Resource Report NPS/NRPC/GRD/NRR—2004/001 

NPS D-450, August 2004 

National Park Service 

Director • Fran P. Mainella 

Natural Resource Stewardship and Science 

Associate Director • Michael A. Soukup 

Natural Resource Program Center 

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

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

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

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

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

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

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

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

outside units of the national park system. 

Geologic Resources Division 

Chief • David B. Shaver 

Planning Evaluation and Permits Branch Chief • Carol McCoy 

Credits 

Author • Trista Thornberry-Ehrlich

Editing • Sid Covington and Bruce Heise 

Digital Map Production • Stephanie O’Meara, Matt Schaffer, and Rachel Johnson 

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 

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National Park Service 

U.S. Department of the Interior