Document Type


Date of Degree Completion

Winter 2018

Degree Name

Master of Science (MS)


Cultural and Environmental Resource Management

Committee Chair

Patrick T. McCutcheon

Second Committee Member

Karl D. Lillquist

Third Committee Member

Patrick M. Lubinski


The Sunrise Ridge Borrow Pit Site is a precontact archaeological site located in the upland forest soils of Mount Rainier National Park. Site stratigraphy is complicated, consisting of tephra deposits from mostly known origins that are intercalated with dark sediments of unknown origin, referred to here as dark mats. Precontact occupation has been split previously into two components based on the ambiguous depositional history of the dark mats, notably their unknown parent material, depositional environment, and relationship with adjacent tephra strata. Stratigraphic samples from excavation units, features, and one off-site excavation unit was used to investigate these data gaps. Grain size, chemistry, organic content, pH, and calcium carbonate content are characterized to document parent material and depositional environment of adjacent strata. Dark mats typically had higher organic content and similar chemistry and grain-size properties compared to underlying tephra strata, and interpreted as buried A horizons that formed in tephra of known regional origin. However, a few dark mats were reworked, and at times the product of multiple or unknown parent material. These determinations are used to revise a depositional history model of the Sunrise Ridge Borrow Pit Site that places the main occupation at 471 years BP to 2,200 cal years BP yet supports previous site assemblage organization into two precontact components.