Sarah J. Kelloway

doctoral candidate
XRF Technical Officer
University of New South Wales · SSEAU,Mark Wainwright Analytical Centre


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    ABSTRACT: A study has been carried out to test the possibility of measuring detailed quantitative profiles of the abundance of different inorganic elements through exploration cores of coal seams using automated energy-dispersive X-ray fluorescence (ED-XRF) core scanning instrumentation. Such an approach has potential application for rapidly determining the distribution of mineral matter in a coal seam, identifying horizons at which particular elements (such as phosphorus) may be concentrated, evaluating in detail the relationships between different elements in the coal, and maximising the data available to guide broader-scale sampling for conventional analysis programs. Profiling was carried out on a series of segments from a 60 mm diameter core of the Goonyella Middle seam in the northern Bowen Basin of Queensland, using an Itrax core scanner (Cox Analytical, Sweden). The scanning process included high resolution optical imaging, X-radiography, and ED-XRF spectroscopy covering the principal major elements, with XRF spectra being obtained at intervals of 200 μm along the axis of each core. A series of calibration curves derived from separately-scanned pressed pellets of reference coals was used to determine the concentration of each element for each step in each sample, allowing a set of quantitative element profiles to be created for each core segment. These were evaluated in conjunction with the relevant X-radiographs and optical images to provide an integrated basis for assessing the variations in inorganic element characteristics through the core sections. The results were also compared to conventionally-determined chemical and mineralogical data for a representative core, to confirm the validity of the quantifications developed.
    International Journal of Coal Geology 08/2014; · 3.31 Impact Factor
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    ABSTRACT: A geochemical study using pXRF and LA–ICP–MS to characterise artefacts from sites dating to the initial phase of colonisation on Aore and Malo islands, Vanuatu, has confirmed the dominance of obsidian from the distant Kutau/Bao source in West New Britain, with a smaller group from local outcrops in the Banks Islands, Vanuatu. Three flakes from the Umleang/Umrei source in the Admiralty Islands have also been identified in later levels. Distance fall-off analysis of metric and technological attributes suggests that during the early phase of human colonisation of Remote Oceania, obsidian circulated within a series of separate, loosely connected social spheres.
    Archaeology in Oceania 02/2014; · 1.27 Impact Factor
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    ABSTRACT: Recent developments in instrumentation mean that chemical analysis of large drill cores taken for geological purposes can be performed rapidly at sub-millimetre scales using core scanners equipped with energy-dispersive X-ray fluorescence spectrometers. The present study describes the development of a calibration for the Itrax Core Scanner (Cox Analytical, Sweden), intended for whole cores of coal-seam sections, without the need for sample preparation. The calibration was developed for key major elements (Al, Si, P, S, K, Ca, Ti, and Fe) based on pressed pellets of reference coals, allowing semi-quantitative and, at times, quantitative analyses. The influence of core curvature and surface roughness compared with an ideal flat-surface was also examined using model samples, and their influence on the apparent sample composition evaluated.
    Powder Diffraction 01/2014; doi:10.1017/S088571561400089X. · 0.54 Impact Factor
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    ABSTRACT: We present U-Pb ages of zircons extracted from olive jars recovered from two sites associated with Alvaro de Mendaña y Neyra's colonising expedition to the Solomon Islands, c. 1595–1596 A.D. The olive jars were previously associated with Panamanian and Peruvian origins based on petrological and geochemical studies. To further define provenance, 143 zircons were extracted from five olive jar sherds, analyzed and dated. The resultant U-Pb ages range from the Archaean to the Cenozoic (2977.2 ± 29.0–3.2 ± 4.0 Ma), but the dominance of Cretaceous and Palaeogene ages (∼ 90% of the total age population is between ∼ 145 and 23 Ma) supports a Peruvian origin based on comparative geology, with the Coastal Batholith of Peru a prime candidate area of ceramic production. These results are significant for the characterization of 16th Century Peruvian-made pottery and our understanding of its production and trade.
    Geoarchaeology 01/2014; 29:47-60. · 1.03 Impact Factor
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    Robin Torrence, Sarah Kelloway, Peter White
    The Journal of Island and Coastal Archaeology 05/2013; 8:278-310.
  • Sarah J. Kelloway, Martin Gibbs, Steven Craven
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    ABSTRACT: We present evidence linking vessel forms with ceramic wares resulting from the petrological analysis of 33 sherds from two sixteenth century Spanish colonial sites in the Solomon Islands. Our results expand the range of fabric types previously published, and comparative literature analyses support earlier studies suggesting probable ceramic origins in the Americas and Spain.
    Archaeology in Oceania 01/2013; 48(1):53-59. · 1.27 Impact Factor
  • Robin Torrence, Sarah J. Kelloway, Peter White
    The Journal of Island and Coastal Archaeology 01/2013; 8(2):278-310.
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    Analytical Archaeometry, Edited by Howell G. M. Edwards, Peter Vandenabeele, 01/2012; Royal Society of Chemistry.
  • Robin Torrence, Peter White, Sarah J. Kelloway
    International Association for Obsidian Studies Bulletin. 01/2012; 46:9-15.
  • Sarah J. Kelloway, Judy Birmingham
    Australasian historical archaeology: journal of the Australasian Society for Historical Archaeology 01/2010; 28:35-42.
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    ABSTRACT: Obsidian is a naturally occurring volcanic silicate glass produced when highly viscous felsic lava cools rapidly through the glass transition temperature, not allowing sufficient time for crystal growth. Obsidian was a popular raw material in prehistory because its amorphous and isotropic nature means that little force is required to produce conchoidal fractures of predictable shapes and sizes and it is easily flaked or knapped into desired shapes.A class of obsidian artefacts known as ‘stemmed tools’ has been found in locations across lowland Papua New Guinea and has been roughly dated to the early and middle Holocene periods (ca. 10,000–3400 BP). The rarity of obsidian in the natural world, the large size, fragility, brilliance, and distinctive shapes of these objects, as well as their manufacture by craft specialists, suggest that the tools were highly valued in the past.This inter-disciplinary project aims to determine when and how prehistoric obsidian stemmed tools were used to structure social relations and if they defined status differences. This involves studying the history, typology, technology, function, and geological sources of the stemmed tools and comparing this information with other highly worked stone tools from the major obsidian sources of West New Britain and Manus.Raman spectroscopy and multivariate analysis have been previously used by the authors to discriminate between three major Pacific obsidian sources, an important first step in tracking the movement of stemmed tools through social networks. This paper assesses the viability of using a portable Raman spectrometer (EZRaman-i, 785 nm, ∼6 cm−1 spectral resolution) for identification of the geological source of obsidian through the comparison of spectra collected from 65 samples of known provenance using both a portable and laboratory-based instrument (Renishaw inVia, 785 nm, ∼1–2 cm−1 spectral resolution). The paper demonstrates that results achieved with the portable instrument are similar to those obtained with a laboratory-based instrument.
    Vibrational Spectroscopy 01/2010; 53(1):88-96. · 1.75 Impact Factor

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