Methods of dating glass beads from protohistoric sites in the South Platte River Basin, Colorado

Abstract

Morphological characteristics and chemical trace elements counts acquired using Laser Ablation-Inductively Coupled Plasma-Mass Spectrometry analyses were documented for glass trade beads from 24 protohistoric archaeological assemblages in the South Platte River Basin. The resulting database was used to provide quantitative descriptions of each recorded assemblage and to characterize the types of glass beads currently reported in the region. Statistical analyses were then conducted to determine if and to what extent morphological and chemical traits change through time. Characteristics of beads in dated contexts were then used to develop a linear regression model in an attempt to determine if it is possible to estimate the age of beads from undated contexts. It is concluded that morphological and chemical characteristics of glass beads in dated contexts can be used to estimate the age of glass beads in undated contexts using linear regression. The results of this thesis demonstrate that morphological characteristics are currently more accurate and precise than chemistry although both methods hold potential for revision and improvement as more dated sites become available to supplement the statistical models.