Browsing by Author "Spooner, NA"

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    Cultural innovation and megafauna interaction in the early settlement of arid Australia
    (Springer, 2016-11-02) Hamm, G; Mitchell, P; Arnold, LJ; Prideaux, GJ; Questiaux, D; Spooner, NA; Levchenko, VA; Foley, EC; Worthy, TH; Stephenson, B; Coulthard, V; Coulthard, C; Wilton, S; Johnston, D
    Elucidating the material culture of early people in arid Australia and the nature of their environmental interactions is essential for understanding the adaptability of populations and the potential causes of megafaunal extinctions 50–40 thousand years ago (ka). Humans colonized the continent by 50 ka1, 2, but an apparent lack of cultural innovations compared to people in Europe and Africa3, 4 has been deemed a barrier to early settlement in the extensive arid zone2, 3. Here we present evidence from Warratyi rock shelter in the southern interior that shows that humans occupied arid Australia by around 49 ka, 10 thousand years (kyr) earlier than previously reported2. The site preserves the only reliably dated, stratified evidence of extinct Australian megafauna5, 6, including the giant marsupial Diprotodon optatum, alongside artefacts more than 46 kyr old. We also report on the earliest-known use of ochre in Australia and Southeast Asia (at or before 49–46 ka), gypsum pigment (40–33 ka), bone tools (40–38 ka), hafted tools (38–35 ka), and backed artefacts (30–24 ka), each up to 10 kyr older than any other known occurrence7, 8. Thus, our evidence shows that people not only settled in the arid interior within a few millennia of entering the continent9, but also developed key technologies much earlier than previously recorded for Australia and Southeast Asia. © 2016, Nature Publishing Group.
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    Environmental change through the last glacial cycle at Fraser Island, subtropical Australia
    (International Union for Quaternary Research (INQUA), 2019-07-29) Kemp, J; Heijnis, H; Longmore, M; Gadd, PS; Spooner, NA; Questiaux, D
    Recent programs to extract detailed and longer records of Australia’s Pleistocene environments have produced a number of efforts to analyse long sedimentary sequences in the subtropical sand islands of Australia’s east coast. Echo Lake is a perched fen within ancient dune sands on Fraser Island at 25° S that provides a record of precipitation change over ~100 ka. A 12 metre core into the (now) ephemeral swamp revealed lacustrine sedimentation in a period of higher precipitation, followed by a transition to swamp sedimentation as water levels fell. The chronology, based on 14C and OSL ages, suggests parts of the record may be interrupted or lost owing to drying or burning of the surface. Here we present an updated OSL chronology together with pollen analysis and ITRAX-XRF proxies for palaeoenvironmental change over the last glacial cycle in subtropical Australia.
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    Radionuclide uptake mechanisms by native flora in the vicinity of uranium mines in arid South Australia
    (ICRP, 2019-11-17) Pandelus, SB; Pring, A; Johansen, MP; Payne, TE; Stopic, A; Spooner, NA; Kalnins, GAG; Popelka-Filcoff, RS
    Environmental risk assessments for radiological impacts follow internationally accepted methods including use of the Environmental Risk from Ionising Contaminants: Assessment and Management (ERICA) tool. Concentration ratios (ratio of radionuclides in an organism to that of its host soil/water- CR) are an essential input for these models. However, the available international input data are primarily from temperate Europe and North America, and may not apply in arid conditions. Previous studies have shown that Australian native species accumulate radionuclides from their environment differently when compared to similar species from other climates. This research aims to develop a concentration ratio dataset relevant for U and Th series radionuclides in arid and semi-arid conditions. Olympic Dam, operated by BHP, is a large copper, uranium, gold and silver producer in South Australia, and utilises underground mining, with the ore being processed on site. To examine radionuclide uptake mechanisms by native flora, samples of flora and adjacent soil have been collected at Olympic Dam. Analyses of flora and soil samples included gamma-ray spectroscopy, neutron activation analysis, alpha-particle spectroscopy and inductively coupled plasma mass spectrometry (ICP-MS). Alternative analytical methods have been incorporated including alpha track analysis for flora samples. Alpha track analysis uses a nuclear emulsion gel layer applied to the individual leaf sample. Analysis of the gel is used to identify radionuclide accumulation and spatially-resolve its location within structures of the leaves. Soil from the surface to 10 cm below the surface was analysed by ICP-MS. Results show a gradient of uranium concentration from 4 ppm at the surface to 0.5 ppm at a depth of 10 cm. The soil depth profile data show that the most probable mechanism of radionuclide transport is airborne and therefore any potential uptake into flora is influenced by the depositional effects on the soil surface. Overall this research provides a better understanding of the behaviour of radionuclides in an arid environment and provides data on the mechanisms of radionuclide uptake in flora. It augments existing international data for use in models in Australia and other localities with similar arid environments.
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    Sedimentation and vegetation change through the last glacial cycle at Echo Lake, Fraser Island
    (Australiasian Quaternary Association Inc., 2018-12-10) Kemp, J; Heijnis, H; Longmore, M; Gadd, PS; Spooner, NA; Questiaux, D
    Echo Lake is an ephemeral swamp perched above the groundwater table within the subtropical dunes of Fraser Island at 100 m above sea level. A 12 metre core was extracted in 1997-1998, with preliminary pollen analysis and dating suggesting the site preserved a palaeoenvironmental record beginning at 2 ka and spanning most of the last glacial cycle. However, the chronology has been problematic and sedimentation may have been interrupted or lost through drying and burning of the surface. Radiocarbon and optically stimulated luminescence (OSL) dating suggested an age for the base of the sedimentary sequence of at least 100 ka. Here we present a new chronology based on OSL on lake sediments together with ITRAX-XRF proxies for palaeoenvironmental change. © Author(s)