Comparison of Radiometric Dating Techniques: Pacific Northwest

Presenter Information

James Brown

Document Type

Oral Presentation

Campus where you would like to present

SURC Ballroom B/C/D

Start Date

21-5-2015

End Date

21-5-2015

Keywords

Radiocarbon Dating, Thermoluminescence Dating, Archaeology

Abstract

Radiometric dating is problematic in non-midden sites of the Pacific Northwest. Charcoal is ubiquitous in the forest soils and unburned bone readily dissolves. This fact impedes development of regional chronologies and understanding of the process of resource intensification that was so important to development of Northwest cultures. To alleviate this deficiency, DirectAMS and Central Washington University undertook research to demonstrate the validity of alternatives to traditional radiocarbon dating of charcoal and bone, by using radiocarbon dating of calcined bone and luminescence dating. Calcined bone (i.e., bone burned in excess of 600°C) survives well in archaeological sites with acidic soils that are common to archaeological contexts along the Northwest Coast and has been found in the Old World to provide accurate radiocarbon dating. Luminescence dating can be applied to fire-cracked rock, which is common, particularly in food processing features. We developed a protocol for comparing calcined bone and luminescence dates with charcoal dates, taking all from the same features contexts. The comparison of the radiocarbon dating of charcoal and calcined bone to the luminescence dating of fire-cracked rock identifies the differences in the events that each medium dates and their association with the cultural activity associated with the cooking features. Results were compared for seven sites, demonstrating the validity of this approach to solving the region’s dating dilemma.

Poster Number

45

Faculty Mentor(s)

Steven Hackenberger, Patrick McCutcheon

Department/Program

Resource Management

Additional Mentoring Department

Anthropology & Museum Studies

Additional Mentoring Department

Anthropology and Museum Studies

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May 21st, 11:30 AM May 21st, 2:00 PM

Comparison of Radiometric Dating Techniques: Pacific Northwest

SURC Ballroom B/C/D

Radiometric dating is problematic in non-midden sites of the Pacific Northwest. Charcoal is ubiquitous in the forest soils and unburned bone readily dissolves. This fact impedes development of regional chronologies and understanding of the process of resource intensification that was so important to development of Northwest cultures. To alleviate this deficiency, DirectAMS and Central Washington University undertook research to demonstrate the validity of alternatives to traditional radiocarbon dating of charcoal and bone, by using radiocarbon dating of calcined bone and luminescence dating. Calcined bone (i.e., bone burned in excess of 600°C) survives well in archaeological sites with acidic soils that are common to archaeological contexts along the Northwest Coast and has been found in the Old World to provide accurate radiocarbon dating. Luminescence dating can be applied to fire-cracked rock, which is common, particularly in food processing features. We developed a protocol for comparing calcined bone and luminescence dates with charcoal dates, taking all from the same features contexts. The comparison of the radiocarbon dating of charcoal and calcined bone to the luminescence dating of fire-cracked rock identifies the differences in the events that each medium dates and their association with the cultural activity associated with the cooking features. Results were compared for seven sites, demonstrating the validity of this approach to solving the region’s dating dilemma.