Pacific obsidian sourcing by portable XRF

Abstract

the use of portable XRF analysis to characterise the geochemistry of Pacific obsidians is reported. Obsidian source samples from New Britain, the Admiralties, Fergusson Island and the Banks Islands were successfully characterised and then used to source 966 samples of obsidian from three (SE=SZ-8, SE-RF-2, SE-RF-6) Reef/Santa Cruz lapita sites. the analysis demonstrates the capabilities of portable XRF and confirms the previous analysis of this material by combined density and PIXE-PIGME techniques. Our conclusions also indicate the importance of the Bao source region at talasea and support the earlier suggestion that during the lapita period an important passage crossed the Willaumez Peninsula in the vicinity of the talasea airstrip and the Bao sources.

Tongan and Samoan volcanic glass: pXRF analysis and implications for constructs of ancestral Polynesian society

“…Phillips andSpeakman (2009: 1262) succinctly characterize pXRF as an "analytically accurate and precise method" for their study of Kuril Island obsidians from the Russian Far East. Sheppard et al (2010) similarly demonstrate the efficacy of pXRF specifically for southwest Pacific obsidian studies, successfully differentiating geological samples for West New Britain, Admiralty Islands, Ferguson Island and Banks Islands sources. They further analyze a large number (n ¼ 966) of archaeological materials from Reef/ Santa Cruz Island sites, replicating earlier PIXE results and refining source region identifications.…”

“…To calibrate results, NIST SRM-278 standard obsidian (powdered obsidian from Clear Lake, Newberry Crater, Oregon) and laboratory specific powdered obsidian standards (MI 9.3, determined by WD-XRF in the Department of Geology, University of Auckland) were also run. Elemental values were calibrated using the method and correction factors reported in Sheppard et al (2010: Table 1). …”

Evaluation of portable X-ray fluorescence (pXRF) in exploration and mining: Phase 1, control reference materials

“…Other papers in mineral exploration include: Vanhoof et al (2004), ED-XRF (lab and portable instruments) in the assessment of contaminated soils; Makinen et al (2006), performance of pXRF in the analysis of soils for As and Cu; Binstock et al (2008), Pb by pXRF in contaminated soils; Markey et al (2008), investigation of different ways of drying the soil sample prior to Pb determination as an alternative to the EPA-recommended oven procedure; Morris (2009), study of count time, detection limit, precision, accuracy, and effects of the sample bag; Haffert & Craw (2009), evaluation of accuracy in a survey of soils and sediments for As, with moisture correction; Sheppard et al (2010), characterization of obsidian samples; Peinado et al (2010), pXRF as a screening tool in a study of the spatial distribution of As, Pb, Zn and Cu in soils; Berger et al (2010), sulphur in sediments using pXRF with a helium path; and Kenna et al (2011), calibration strategies in the analysis of soils and sediments for various elements. More recent papers of relevance include: Marsala et al (2012), mineralogical and lithological characterization of drill cuttings; Kessler & Nagarajan (2012), determination of Rb in sedimentary rocks; Wu et al (2012), reliability of pXRF in the analysis of soils for various elements; Parsons et al (2013), optimization of pXRF to determine As in soils; and Rowe et al (2012), optimization of and calibration strategies for pXRF analysis of mudrock chemostratigraphy and geochemistry.…”

Obsidian sources and distribution systems in Island Southeast Asia: new results and implications from geochemical research using LA-ICPMS

“…It is proposed that future projects and surveys include geological investigation of possible undetected obsidian outcrops in Borneo, Sulawesi, Mindanao, and particularly the Moluccas and the Lesser Sunda chain. These aims get easier to achieve as new geochemical analytical techniques, for example non-destructive portable XRF machines (Sheppard et al, 2010), become more widely available. The techniques allow for in situ analysis of outcrops and larger ensembles of obsidian artefacts, avoiding the danger of biased selection of artefacts.…”