Relationships Between Snake River Paleofloods, Occupational Patterns and Archaeological Preservation at Redbird Beach Archaeological Site in Lower Hells Canyon, Idaho

Tabitha Trosper
August 2011

Abstract

The Snake River basin drains 282,000 km2 of the northwestern U.S. and is the largest tributary to the Columbia River. Redbird Beach, an archaeological site located in the lower Hells Canyon reach of the Snake River, contains extensive vertical exposures of archaeological materials interbedded with Snake River flood sediments. Redbird Beach formed in the lee of the Redbird Creek debris fan, is composed of interfingering deposits from large floods on the Snake River and locally-derived alluvial sediments from Redbird Creek. Through stratigraphic analyses of slackwater deposits, this study compares the temporal and spatial patterns of human occupation at Redbird Beach with variations in the magnitude and frequency of floods from the Snake River. Results of this study will form a key component of a regional synthesis of floods and climate change in the inland Northwestern U.S., and contribute to our understanding of the archaeological record along this major regional waterway.

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