Using pXRF and ICP-MS analyses to create a calibration curve for silicified sandstones in the upper mississippi river valley (UMRV)

Abstract

Silicified sandstones are commonly found in lithic assemblages at sites in, and around, the Upper Mississippi River Valley (UMRV). This study resulted in compositionally characterizing three silicified sandstones (Arcadia Ridge, Cataract, and Hixton) and created calibration and quantification standards for raw pXRF data using ICP-MS data as my known. My results indicate that pXRF analysis, coupled with quantification and calibration standards from ICP-MS analysis, can be conducted reliably on heterogeneous materials like silicified sandstones, to varying degrees dependent on the element being analyzed. In addition I found that these three silicified sandstones can be differentiated at the geologic formation, by using analysis of concentrations of several elements. The results of this study will allow for the non-destructive geochemical sourcing of these materials, to the formation level, using pXRF analysis alone. Upon determining lithic resource procurement strategies at sites, human behaviors can be examined by looking at the relationship between the lithic material utilized and the distance of the site from the source. These behaviors include, population movements, landscape patterning, and trade or exchange networks.