Browsing by Author "David, B"

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    AMS radiocarbon dating of micro samples from the rock paintings of Malakula (Vanuatu)
    (Oxford University School of Archaeology, 2002-04-09) Zoppi, U; David, B; Wilson, M; Hua, Q; Williams, AA; Watchman, A
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    Determining the origin and changing shape of landscape-scale rock formations with three-dimensional modelling: the Borologa rock shelters, Kimberley region, Australia
    (Wiley, 2021-05-02) Genuite, K; Delannoy, JJ; David, B; Unghango, A; Balanggarra Aboriginal Corporation; Cazes, G; Fulop, R; Fink, D; Codilean, AT; Ouzman, S; Veth, P; Harper, S; Green, H; Finch, D; Urwin, C
    Archaeologists often wonder how and when rock shelters formed, yet their origins and antiquity are almost never systematically investigated. Here we present a new method to determine how and when individual boulders and rock shelters came to lie in their present landscape settings. We do so through 3D laser (LiDAR) mapping, illustrating the method by example of the Borologa Aboriginal site complex in the Kimberley region of northwestern Australia. Through a combination of geomorphological study and high-resolution 3D modelling, individual blocks of rock are refitted and repositioned t680their originating cliff-line. Preliminary cosmogenic nuclide ages on exposed vertical cliff faces and associated detached boulders above the Borologa archaeological sites signal very slow detachment rates for the mass movements of large blocks down the Drysdale Valley slopes, suggesting relative landscape stability over hundreds of thousands of years (predating the arrival of people). These findings offer hitherto unknown details of the pace of regional landscape evolution and move us toward a better understanding of patterns of human occupation in a context of relatively stable rock outcrops both within the sites and across the region. © 1999-2021 John Wiley & Sons, Inc
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    Marine carbon reservoir variability in Torres Strait: preliminary results of AMS dating of live-collected shell specimens.
    (International Union for Quaternary Research, 2007-07) Ulm, S; Barham, AJ; David, B; Jacobsen, GE; McNiven, IJ; Petchey, F; Rowland, MJ
    Despite routine dating of marine shell by Quaternary scientists in the Torres Strait region, no systematic evaluation of the applicability of the recommended DeltaR value has been undertaken. This value can be shown to be problematic. It is based on only three samples from Torres Strait and two from the west coast of Cape York Peninsula, together spanning 125±60 to -14±60 years; the samples are from different oceanographic provinces; the dated taxa are not amongst those commonly dated by contemporary researchers; and all of the dates were obtained over 20 years ago before the advent of high precision AMS dating. This project attempts to address this deficiency through the dating of a suite of well-provenanced live-collected shell specimens using the high precision ANTARES AMS facilities at ANSTO. Dated samples are largely derived from a unique assemblage of well-documented live-collected shell specimens in the Australian Museum from Murray Island and Albany Passage collected by Charles Hedley in August-October 1907, supplemented by smaller collections from elsewhere in Torres Strait. Sample selection focused on suspension-feeders (Arcidae, Mesodesmatidae, Veneridae), although carnivores (Volutidae), herbivores/omnivores (Neritidae) and algae grazers (Trochidae) were included to examine inter-taxa variability. Preliminary results help establish more robust regional DeltaR values for the region based on shellfish commonly dated by Quaternary scientists and allow examination of localised variability in DeltaR values. These findings have broad implications for refining chronologies in coastal archaeology and geomorphology in the Torres Strait region, including studies of sea-level change, reef and coral cay development, coastal dune sequences, storm event frequency and archaeological trends.
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    Radiocarbon determinations for Chillagoe rock paintings: small sample AMS
    (Australian Institute of Nuclear Science and Engineering, Australian Nuclear Science and Technology Organisation and Australian Museum, 1997-02-11) Armitage, RA; David, B; Hyman, M; Rowe, MW; Tuniz, C; Lawson, EM; Jacobsen, GE; Hua, Q
    Indirect dating methods have been applied to the rock paintings of Chillagoe, north Queensland, revealing patterns of superimposition, depictions of items of known antiquity, the use of fragile paints such as mud, and in-situ pigment stratigraphies (David 1994). These patterns suggest that the Chillagoe rock paintings are relatively young, likely less than 3000 years old. A change in the geographical distribution of rock painting styles suggests a regionalization of the styles starting around 3000 years BP. Such regionalization implies that major cultural changes accompanied the changes in rock painting styles. This model of temporal change is now being investigated through a collaboration between the University of Queensland, ANSTO and the Department of Chemistry, Texas A&M University to directly analyze radiocarbon in the charcoal pigments in several of the Chillagoe rock paintings. Samples were collected from fourteen separate charcoal rock drawings at five rock shelters in the Chillagoe region. A small area of each drawing was scraped using a sterile scalpel blade and the material was collected on a square of aluminum foil. The resulting powder was a mixture of limestone substrate, charcoal pigment and overlying accretion. Latex gloves were worn when sampling and when handling the foil to prevent contamination. Enclosed in the foil, each sample was placed in a zipper-seal polyethylene bag, carefully labeled and brought back to the laboratory at Texas A&M University. They were then photographed under magnification and weighed after foreign debris (fabric fibers, etc.) were removed; weights ranged from 9 to 66 milligrams of total material. One sample weighing 263 milligrams was to be divided for duplicate analysis. Typically, 100 micrograms of carbon is sufficient for radiocarbon analysis by AMS.