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West of the Aleutian Range in southwest Alaska, the Alagnak Wild River protects 110 km (67 mi) of the Alagnak River: its scenery, natural features, cultural heritage and recreation. It lies in the Bristol Bay and Lake and Peninsula Boroughs.
Rafting the Alagnak. Image from the National Park Service's Geologic Resources Inventory.
The river
Established on December 2, 1980, the wild river covers about 12,409 hectares (30,741 acres). The river rises in neighboring Katmai National Park and Preserve and flows northwest from Kukaklek Lake to join the Kvichak River. It supports a wide range of wildlife, including an important sockeye (red) salmon fishery, and is a critical natural resource for southwest Alaska.
An active landscape
Volcanism, glaciation, wind and river erosion, and active tectonics have all shaped the valley.
| Age | Unit | Where |
|---|---|---|
| Late Jurassic and older | Kakhonak Complex, metamorphic rock | the oldest rock, along the northeastern boundary |
| Eocene–Oligocene | Meshik Volcanics | exposed as the river flows northwest |
| Pleistocene | glacial drift and outwash of the Mak Hill and Brooks Lake glaciations | most of the valley |
| Quaternary | alluvium (loose clay, silt, sand and gravel), alluvial terraces, solifluction ("soil flow") deposits, abandoned channel deposits, eolian deposits | along the river |
Geologic map of Alagnak Wild River. Image from the National Park Service's Geologic Resources Inventory.
Maps and inventories
The Park Service's Geologic Resources Inventory, which produces digital geologic maps and reports for more than 270 natural resource parks, has a map and report for the Alagnak, and a Soil Resources Inventory has been completed. Both are on the NPS DataStore.
Sources
Based on "NPS Geodiversity Atlas—Alagnak Wild River, Alaska," National Park Service Geologic Resources Inventory, which cites Anderson (2017) and Hults and Fierstein (2016); a work of the United States government in the public domain. The Geologic Resources Inventory report cover shown on the atlas page is not reproduced.
Licencia: CC0 1.0 (dominio público) · Adaptado de www.nps.gov
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