NPS Geodiversity Atlas—Alagnak Wild River, Alaska

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.

In-depth geologic information is contained in the baseline inventory products of the Geologic Resources Inventory, see table below.

Introduction

Alagnak Wild River (ALAG) is west of the Aleutian Range in the Bristol Bay and Lake and Peninsula Boroughs, Alaska. Established on December 2, 1980, ALAG encompasses ~12,409 hectares (30,741 acres) and protects 110 km (67 mi) of the Alagnak River, its scenic landscape, natural features, cultural heritage, and recreational activities (Anderson 2017). The headwaters of the Alagnak River are in neighboring Katmai National Park and Preserve, where the river flows northwest from Kukaklek Lake to its confluence with the Kvichak River. The river system is home to a diverse array of wildlife, including an important sockeye (red) salmon fishery, and is a critical natural resource for southwest Alaska (Hults and Fierstein 2016).

Geologic Setting

The geology along the Alagnak River reflects an active landscape shaped by the dynamic forces of volcanism, glaciation, wind and river erosion, and active tectonics. Geologic units along the Alagnak River Valley predominantly consist of Pleistocene glacial drift and outwash deposits of the Mak Hill Glaciation and Brooks Lake Glaciation. The oldest units within the park unit are found along the northeastern boundary and are the metamorphic rocks of the Late Jurassic and older Kakhonak Complex. As the Alagnak River flows northwest, exposed units along the river include the Eocene–Oligocene Meshik Volcanics, Pleistocene glacial deposits, and Quaternary alluvium (unconsolidated clay, silt, sand, and gravel), alluvial terrace deposits, solifluction deposits (“soil flow”), abandoned channel deposits, and eolian deposits.

Maps and Reports

Geologic Resources Inventory

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 2675. To search for additional information, visit the Data Store.

Soil Resources inventory

A NPS Soil Resources Inventory project has been completed for Alagnak Wild River and can be found on the NPS Data Store.

Source: Data Store Saved Search 2688. To search for additional information, visit the Data Store.

GRI Geology Image Gallery

Related Links

• Alagnak—Erosion of riverbanks

• Alagnak—Park Home

• NPS—Glaciers and Glacial Landforms

• NPS—Plate Tectonics

• NPS—Geologic Time

• NPS—Geology

• Alaska Division of Geological & Geophysical Surveys

Related Articles

Alagnak Wild River

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.

NPS Geodiversity Atlas