Trace element studies of the Arkansas novaculite

Novaculite color and texture can be widely variable. This pilot study assessed how much variability in trace element concentration is detectable throughout the formation as well as within individual sample areas and compared two analytical procedures for their suitability for source characterization in archaeology. Trace-element analysis was conducted through the use of instrumental neutron activation analysis (INNA) at the University of Missouri Research Reactor and scanning electron microscopy-energy dispersive x-ray spectrometry (SEM-EDS) at the University of Arkansas ESEM laboratory. The raw data from INAA were subjected to principle component analysis with encouraging results. Two distinct populations, Arkansas-Oklahoma and Texas, have emerged in the analysis. Three smaller groups that correspond with the sample areas can also be seen in the Arkansas-Oklahoma population. While the results are preliminary they do provide a glimpse of the potential variation present throughout the formation at large. Based on these results further study is recommended to further characterize the formation as a whole, including the novaculite outcrops in Oklahoma and Texas. A comparison of the results from the INAA and EDS methodologies was also undertaken to determine whether EDS was a valid method for trace element characterization. The EDS results from this study are not amenable to the same statistical analyses that the INNA were. Therefore, further testing using EDS is recommended to fully examine the utility of this methodology.