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.
Geologic Features and Processes
[Site Under Development]
Lake Clark is the scene of a dynamic, living geology. A young landscape shaped by uplift, intrusion, earthquakes, volcanism, and glaciation. The Aleutian Range in Lake Clark is a segment of the circum-pacific Ring of Fire, one of the most active volcanic belts in the world. Quaternary volcanism in the Aleutians is the result of plate convergence, approximately 7.0 cm/year, between the American and Pacific plates (Kienle and Swanson, 1983). Modern tectonism is evident from the frequent strong earthquakes and four active volcanoes in the region (Redoubt, Illiamna, Augustine, and Douglas). Clusters of shallow and deep seismicity, with some magnitudes exceeding 6.0 on the Richter scale, have been recorded beneath Iliamna, Augustine, and Douglas volcanoes (Hampton, 1982).
Most of the southern portion of the park, east of Lake Clark, consists of sedimentary andmetamorphic rock of Mesozoic age. The geology in the northern half of the park is dominated by Tertiary and Mesozoic intrusive rocks (Dale and Stottlemyer, 1986). In detail, the geology and associated structure are very complex with igneous, metamorphic and sedimentary lithologies interacting at various scales.
Two major thrust faults are located within the park. The Bruin Bay Fault can be traced 300 miles from Becharof Lake on the Alaska Peninsula to Mount Susitna, northwest of Anchorage, bisecting Chinitna and Tuxedni bays. The Lake Clark Fault, also referenced as the Castle Mountain Fault by Stone (1983), runs approximately 80 miles to the northeast end of Lake Clark (Alaska Geographic Society, 1986).
The Lake Clark Fault underlies Lake Clark, structurally producing the lake's long linear geometric shape. The fault is characterized by a right lateral displacement of approximately 8 miles (Ivanhoe, 1962).
Geologic Resources Inventory
- 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.
- Lake Clark—Volcanoes
- Lake Clark—Mountains
- Lake Clark—Glaciers
- Lake Clark—Fossils
- Lake Clark—Rivers and Streams
- Lake Clark—Photo Gallery
- Lake Clark—Park Home
- NPS—Beaches and Coastal Landforms
- NPS—Fossils and Paleontology
- NPS—Glaciers and Glacial Landforms
- NPS—Volcanic Landforms: Extrusive Igneous
- NPS—Geologic Time
Related ArticlesLake Clark 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.
Series: National Park Service Geodiversity Atlas
Last updated: October 30, 2019