Estimation of the Radiocarbon Reservoir Effect, Snake River Basin, Northwestern North America

Abstract

Many archaeological sites along coastlines and rivers contain large quantities of marine and riverine bivalve shell. Often shell is the only datable organic material available to determine radiocarbon age estimates of features and to build regional chronologies. Shell is difficult to date accurately because of reservoir effects, and archaeologists have avoided it despite its abundance. If reservoir effects are understood, shell can provide accurate radiocarbon age estimates. This report provides an example using regression relations computed from radiocarbon assays of paired shelll charcoal samples from archaeological sites along the middle and lower Snake River, Northwestern North America.