Comparison of XRF and PXRF for analysis of archaeological obsidian from southern Perú

Abstract

Chemical sourcing is becoming an increasingly important component of archaeological investigation. Instruments used for elemental analysis generally must be operated in a controlled laboratory environment. Further, many methods require destruction of a small portion of the objects under investigation. These facts inhibit the application of chemical sourcing studies in a number of research contexts. Use of portable nondestructive instruments would resolve these issues. Sixty-eight obsidian artifacts from the site of Jiskairumoko, in southern Perú, were examined by X-ray fluorescence spectrometry (XRF) and portable X-ray fluorescence spectrometry (PXRF). Results were compared for consistency in terms of source determination and individual element concentrations. Both instruments determined that the same sixty-six artifacts derived from the Chivay obsidian source and both identified the same two artifacts that could not be assigned to source. Individual element comparisons showed significant differences, but these can be resolved through instrument cross calibration, and differences had no bearing on source identification. PXRF was found suitable for determining obsidian sources in southern Perú and for identifying specimens that require more sensitive analytical methods such as, instrumental neutron activation analysis (INAA). Regular use of Chivay at Jiskairumoko suggests consistent trade relationships developed during the Archaic.

Exotic Goods, Chivay Obsidian, and Sociopolitical Change in the South-Central Andes

“…The vertical complementary model has been the subject of much discussion in the Andes (Aldenderfer 1993;Masuda et al 1985;Van Buren 1996), with related models proposed such as the "altiplano mode" of integration which proposes extensive networks based on trade in the (Browman 1981(Browman , 1990). In support of Browman's "altiplano mode," regional distributions of Chivay obsidian appear to be confined to middle-and high-altitude sites throughout Andean prehistory (Burger et al 2000;Craig et al 2007;Frye et al 1998;Giesso 2000;Tripcevich 2007: 183-191).…”

PXRF Determination of the Obsidian Industry from the S–F Area of Piani della Corona EBA Settlement (Bagnara Calabra–RC, South Italy)

“…Energy dispersive X-ray fluorescence (ED-XRF) has since been established, and hand-held models of XRF have become a preferred instrument for being portable, non-destructive, and increasingly, trace element detection abilities. pXRF and lab XRF have been compared (Craig et al, 2007), and recently pXRF analyses have been integrated with analyses using other instruments and methodologies (Orange et al, 2017). The literature on pXRF and obsidian is vast, and suffices here to say that the instrument has sufficient detection abilities to discriminate among sources and subsources within a continental area, with some current instruments achieving high levels of precision (Tykot, 2016).…”

Mobile Spectroscopic Instrumentation in Archaeometry Research

“…[99][100][101][102] All discuss the feasibility of mobile instrumentation compared to traditional laboratory-based XRF and alternative techniques such as instrumental neutron activation analysis for achieving the high accuracy required for obsidian sourcing. Quantitation approaches included linear regression, 101 quadratic regression, 99 fundamental parameters, 100 and corrections utilizing Compton scatter. 102 And while the researchers all concluded that mobile XRF can be successfully used for obsidian sourcing, concerns were noted by some.…”