Chemical Characterization of Chert Artifacts from Caution Bay, Papua New Guinea: Exploring archaeological resource use via portable X-Ray Fluorescence
thesisposted on 26.11.2018, 21:08 by Gregory Edmond Morrissey
This thesis investigates the potential for the use of Portable X-Ray Fluorescence Spectrometry (pXRF) to identify chemically distinct groups of chert from an archaeological assemblage and explores how this data can be used to explore a range of questions about how chert was selected, used and discarded over time. The assemblage of chert artifacts used in this research is from Caution Bay, Papua New Guinea (PNG). It includes 2,454 chert artifacts from 12 archaeological sites with pre-Lapita, Lapita, and post-Lapita deposits. The pXRF analysis was conducted using a Niton XL3t GOLDD+ in the factory TestAllGeo mode and collected data from a total of 44 different elements. The data produced by the pXRF instrument were investigated using a variety of different statistical analyses and resulted in the successful identification of four chemically distinct groups of chert in the assemblage. These four groups of chemically distinct chert are interpreted as representing four distinct geological outcrops and are referred to here as Geological Source Groups (GSGs). Having identified the four GSGs, they were used to explore the archaeological assemblages from the Caution Bay sites. Each GSG is present from the earliest phase of occupation to the most recent; that is, each GSG occurs through the full span of occupation in each site. However, some GSGs are minimally represented in the earliest and most recent deposits, but occur in significant numbers in the middle phases. The Excavation Units with the greatest number of artifacts also have the greatest diversity of GSGs represented. This observation suggests, a correlation between increased lithic material use and more diverse resource use. A difference in the number of GSGs present at contemporaneous sites suggests that activities with different lithic requirements may have taken place. The occurrence of a range of chert colours indicates that specific colours may have been targeted. Cultural and geographic factors were both considered;without known source locations for the GSGs, however, specific source locations for the archaeological chert samples could not be determined. To further develop the archaeological interpretations of chert-use in Caution Bay, future research involving the locating and geochemical fingerprinting of natural chert outcrops in the broader Caution Bay area is recommended.