NPS Geodiversity Atlas—Glacier National Park, Montana

Geodiversity refers to the full variety of natural geologic (rocks, minerals, sediments, fossils, landforms, and physical processes) and soil resources and processes that occur in the park. A product of the Geologic Resources Inventory, the NPS Geodiversity Atlas delivers information in support of education, Geoconservation, and integrated management of living (biotic) and non-living (abiotic) components of the ecosystem.

glacier report cover with landscape image
In-depth geologic information is contained in the baseline inventory products of the Geologic Resources Inventory, see table below.

Geologic Features and Processes

The Lewis Overthrust – this surface, best seen exposed north of Marias Pass, represents older (950 million years old) limestones, shales, and sandstones thrusted eastward for over 60 kilometers on top of younger (90 million year old) shales. Within the geologic science community, it is considered one of the finest examples of such an overthrust in the world. The relatively hard rocks in the overlying sheet provided the resistance to the alpine glaciers of the last ice age that created the sculpted landforms we see today. Without this hard carapace, the ice would likely have left little relief beneath it, similar to what we see on the Blackfoot Reservation today.

Chief Mountain – standing alone in front of the ranges to its west, Chief Mountain is a klippe, a geologic term for the erosional remnant of older rocks in a thrust sheet completely detached from comparably aged rocks trailing behind. Like the Lewis Overthrust itself, Chief Mountain is considered one of the world’s outstanding examples of a klippe; its images grace the pages of many geologic textbooks.

Sedimentary Rock Structures – while well known among geologists, the general public is largely unaware of the significance of these small features which are remarkably well preserved and represent conditions that the rocks were deposited under. Notable are mud cracks, raindrop impressions, and ripple marks.

Purcell Lava flow and associated features – this igneous dike, whose mineralogy gives it a dark gray to black appearance, was intruded as a molten fluid into the surrounding carbonate rocks. The high temperature of the fluid essentially baked the light gray carbonates into a white chill zone, providing the distinctive white-gray-white striping seen wherever the flow is exposed.

Glacial landforms – almost too many to mention, but notable are bergschrunds, crevasses, cirques, horns, arêtes, hanging valleys, glacial stairways, paternoster lakes, waterfalls, moraines, moraine lakes, and glacial deposits.

Stromatolites – described in the paleontology section.

Pillow basalts – lava extruded onto a lake or ocean floor will solidify in pillow shaped blocks. The inaccurately named Granite Park (actually a basalt), is an excellent location to see these.

Goat lick – the rocks at this location are rich in sodium, something lacking elsewhere in local mountain goats’ diet. This exposure is a significant attraction to goats determined to make up this deficiency.

More information on these features can be found in the Geologic Resources Inventory Report.

Paleontological Resources

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. 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.

All NPS fossil resources are protected under the Paleontological Resources Preservation Act of 2009 (Public Law 111-11, Title VI, Subtitle D; 16 U.S.C. §§ 470aaa - 470aaa-11).

Cave and Karst

There are at least 16 known caves in Glacier National Park with the longest being slightly over 1 mile in length and the deepest being 365 feet deep. The Helena Formation, part of the older Mesoproterozoic units consists of thick beds of dolomite and limestone and contains caves. Eighteen percent of the park is considered to be karst.

All NPS cave resources are protected under the the Federal Cave Resources Protection Act of 1988 (FCRPA)(16 U.S.C. § 4301 et seq.).

Abandoned Mineral Lands

There was considerable mineral exploration activity that predated the establishment of the park in 1910. This includes copper mining and oil and gas exploratory wells. Approximately 28 AML sites having 48 distinct features have been identified in the park.

NPS AML sites can be important cultural resources and habitat, but many pose risks to park visitors and wildlife, and degrade water quality, park landscapes, and physical and biological resources. Be safe near AML sites—Stay Out and Stay Alive!

Geology Field Notes

Students and teachers of college-level (or AP) introductory geology or earth science teaching courses will find that each park's Geologic Resource Inventory report includes the Geologic History, Geologic Setting, and Geologic Features & Processes for the park which provides a useful summary of their overall geologic story. See Maps and Reports, below.

Regional Geology

Glacier National Park is a part of the Northern Rocky Mountains Province and shares its geologic history and some characteristic geologic formations with a region that extends well beyond park boundaries.

Maps and Reports

image of gri geologic map

The Geologic Resources Inventory produces digital geologic maps and reports for more than 270 natural resource parks. The products listed below are currently available for this park, check back often for updates as many maps, reports, and posters are still in progress.
  • Scoping summaries are records of scoping meetings where NPS staff and local geologists determined the park’s geologic mapping plan and what content should be included in the report.
  • Digital geologic maps include files for viewing in GIS software, a guide to using the data, and a document with ancillary map information. Newer products also include data viewable in Google Earth and online map services.
  • Reports use the maps to discuss the park’s setting and significance, notable geologic features and processes, geologic resource management issues, and geologic history.
  • Posters are a static view of the GIS data in PDF format. Newer posters include aerial imagery or shaded relief and other park information. They are also included with the reports.
  • Projects list basic information about the program and all products available for a park.

Source: Data Store Saved Search 2879. To search for additional information, visit the Data Store.

NPS Soil Resources Inventory project has been completed for Glacier National Park and can be found on the NPS Data Store.

Source: Data Store Saved Search 2950. To search for additional information, visit the Data Store.

Related Articles

Glacier National Park

National Park Service Geodiversity Atlas

The servicewide Geodiversity Atlas provides information on geoheritage and geodiversity resources and values within the National Park System. This information supports science-based geoconservation and interpretation in the NPS, as well as STEM education in schools, museums, and field camps. The NPS Geologic Resources Division and many parks work with National and International geoconservation communities to ensure that NPS abiotic resources are managed using the highest standards and best practices available.

For more information on the NPS Geodiversity Atlas, contact us.

Glacier National Park

Last updated: December 28, 2020