Geodiversity Atlas—Southwest Alaska I&M Network Index

Geology and Stratigraphy of the Southwest Alaska I&M Network Parks

The Southwest Alaska Inventory and Monitoring Network (SWAN) includes five national park units located on the Alaska and Kenai peninsulas of southwestern Alaska. The five NPS units are Alagnak Wild River (ALAG), Aniakchak National Monument and Preserve (ANIA), Katmai National Park and Preserve (KATM), Kenai Fjords National Park (KEFJ), and Lake Clark National Park and Preserve (LACL). Collectively, the SWAN park units encompass approximately 3.8 million hectares (9.4 million acres) and preserve exceptional geologic features, landforms, marine coastlines, aquatic systems, wilderness, flora, and fauna.

The SWAN park units preserve a wide variety of geologic features and landscapes including mountains, volcanoes, and glaciers. ANIA preserves a large 3,600-year-old volcanic caldera along the volcanic arc of the Alaska Peninsula and Aleutian Islands. KATM preserves the Valley of Ten Thousand Smokes, Katmai caldera, and Novarupta which formed during the largest volcanic eruption 4 of the 20th century. KEFJ preserves the extensive Harding Ice Field. Geologic Resource Inventory reports for ALAG and KATM (Hults and Fierstein 2016), ANIA (Hults and Neal 2015), KEFJ (Lanik et al. 2018), and LACL (Lanik et al. in press) present detailed information on the geologic resources of these SWAN park units.

A Brief Geologic History

A few examples of events and Network resources in each geologic time period are highlighted below, from youngest to oldest.

Geology & Soils—Southwest Alaska Network Parks

Type Sections—Southwest Alaska Network

The geologic history above is excerpted from a report titled, "National Park Service geologic type section inventory: Southwest Alaska Inventory & Monitoring Network". Type sections are essential reference locations for the geoscientists who study geologic history and paleontology. A summary of the type sections in each park can be found at the links below.

• Alagnak Wild River, Alaska (no designated stratotypes identified)

• Aniakchak National Monument and Preserve, Alaska (contains two identified stratotypes)

• Katmai National Park and Preserve, Alaska (contains six identified stratotypes)

• Kenai Fjords National Park, Alaska (no designated stratotypes identified)

• Lake Clark National Park and Preserve, Alaska (contains seven identified stratotypes)

The full Network report is available in digital format from:

• DataStore - National Park Service geologic type section inventory: Southwest Alaska Inventory & Monitoring Network (nps.gov)

Please cite this publication as:

• Henderson T, Santucci VL, Connors T, Tweet JS. 2021. National Park Service geologic type section inventory: Southwest Alaska Inventory & Monitoring Network. Natural Resource Report. NPS/SWAN/NRR—2021/2296. National Park Service. Fort Collins, Colorado.

NPS Stratotype Inventory

Fossil Resources—Southwest Alaska Network

Between 2002 and 2011, network-based paleontological resource inventories were completed for all the 32 I&M networks, and six of the earliest were completely updated between 2012 and 2016. The report linked below summarizes the paleontological resources of all park units in the Southwest Alaska Inventory & Monitoring Network (SWAN). The report provides geologic background and paleontological resource data for each park to support management operations, planning, and science-based decision making as required by NPS management policies and the Paleontological Resources Preservation Act (2009).

The full report is available in digital format from

• DataStore - Paleontological resource inventory and monitoring Southwest Alaska Network (nps.gov)

Please cite this publication as:

• Kenworthy J and Santucci VL. 2003. Paleontological resource inventory and monitoring Southwest Alaska Network. Southwest Alaska Network, National Park Service.

Related Links

• Southwest Alaska Inventory & Monitoring Network
• NPS Geodiversity Atlas
• NPS—Geologic Resources Inventory

Geodiversity Atlas pages—by Inventory & Monitoring Network

Geodiversity Atlas pages—by State, U.S. Commonwealth, and Territories