Browsing by Author "Patton, NR"

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    Evaluating δ18O and δ13C variations within a modern Biggenden Banded snail (Figuladra bayensis) shell using radiocarbon dating: application for past climate reconstruction
    (Australian Nuclear Science and Technology Organisation, 2021-11-17) Patton, NR; Shulmeister, J; Leng, MJ; Jones, M; Hua, Q; Hughes, CE
    Gastropods are utilized to infer paleoclimate variability due to the preservation and incorporation of stable isotopes (δ18O and δ13C) in their aragonite shells. Analyses along the growth axis of larger gastropods have been suggested to contain high-resolution records of local seasonal climate variability and the organism’s biological life cycle. Here a Figuladra bayensis (Biggenden Banded snail) shell was collected shortly after death from Coalstoun Lakes National Park, Queensland, Australia. A total of 200 samples were collected for δ18O and δ13C analyses and an additional 8 radiocarbon dating samples were collected along the growth axis from the apex to the aperture. Results from our work indicates that the Biggenden Banded snail lived ~4.4 years, with evidence of two aestivation (dormant stage) periods during the dry, cool winters. As a result, its growth rate was episodic with the highest rates of ~90 mm/yr occurring shortly after large rain events. The δ18O and δ13C variation in the shell is closely related to total rainfall, diet and physiological changes. To our knowledge this is the highest resolution isotopic and radiocarbon dated study on a modern terrestrial snail, allowing the nuances of the stable isotope record to be more clearly interpreted and therefore used as a palaeoenvironmental proxy. © The Authors
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    Timing and causes of MIS 4 and MIS 3 glacial advances in South Island, New Zealand
    (International Union for Quaternary Research (INQUA), 2019-07-27) Schulmeister, J; Thackray, GD; Rittenour, TM; Fink, D; Patton, NR
    This poster summarises information on the timing and possible causes of glaciation in New Zealand prior to the LGM (26.5-19 ka). We recognise five regionally identifiable advances in MIS 4 and MIS 3 in South Island, NZ, including one which may mark the start of the LGM, but may also precede it. These advances, all secured by CRN and/or luminescence chronologies, occurred at 65 ± 3 ka, 47.5 ± 3 ka, 38.5 ± 2 ka, 31.5 ± 3 ka, and at 26.5 ± 2 ka. Not all advances have clear linkages to climate but some are coincident with periods of Southern Hemisphere insolation minima (65ka, and 31.5 ka advances), while another occurs during a notably cold phase (38.5 ka) and precipitation may play a role (65 ka and 26.5 ka advances). The timing of greatest glacial extent in the last glacial cycle is not simultaneous across New Zealand. The MIS 4 advance was the greatest in the southern South Island, while the MIS 3/2 advances (26.5-25 ka) were greatest in the central South Island. We attribute these spatio-temporal changes in the timing of maximum glaciation to precipitation changes related to a northward shift in the track of the southern-hemisphere westerlies.
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    The timing and nature of the last glacial cycle in New Zealand
    (Elsevier, 2019-02-15) Shulmeister, J; Thackray, GD; Rittenour, TM; Fink, D; Patton, NR
    This paper constitutes a review of the last (Otiran) glaciation in New Zealand, spanning marine isotope stages (MIS) 4-2. We highlight the nature of glaciation, which is characterised by exceptional sedimentation, relatively mild maritime climatic conditions and the widespread presence of water associated with proglacial settings. These conditions produce glacial systems characterised by extensive outwash fans and relatively small terminal moraines. Extensive recent geochronological work allows us to recognise at least eight glacial advances during the Otiran. These occurred at 65 ± 3.25ka, 47.5 ± 3 ka, 38.5 ± 2 ka, 31.5 ± 3 ka, 26.5 ± 2 ka, 20.5 ± 2 ka, 17 ± 2 ka and 13 ± 1 ka, which we term the Otira 1 to 8 advances, respectively. Though the analytical uncertainty ranges for some of these advances overlap, all are independently distinguished through moraine morphologic relationships and/or stratigraphic relationships in outcrop. Major advances appear to be associated with climate influences such as periods of Southern Hemisphere insolation minima (65ka, and 31.5 ka advances), the last glacial maximum cooling (LGM) (20.5 ka) and periods of Antarctic cooling (13ka). The timing of greatest glacial extent in the last glacial cycle is not simultaneous across New Zealand. The MIS 4 advance was the greatest in the southern South Island, while the MIS 3/2 advances (26.5 ka) were greatest in the central South Island. In the northern South Island and the North Island, MIS 4, MIS 3/2, and the last glacial maximum appear to be equivalent in extent. We attribute these spatio-temporal variations in the timing of maximum glaciation to precipitation changes related to a northward shift in the track of the westerlies. © 2018 Elsevier Ltd.
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    Using stable isotope analysis of archaeological pandanus nutshell to understand past rainfall at Madjedbebe, northern Australia
    (Australian Nuclear Science and Technology Organisation, 2021-11-17) Florin, A; Roberts, P; Marwick, B; Patton, NR; Schilmeister, J; Lovelock, CE; Barry, LA; Hua, Q; Nango, M; Djandjomerr, D; Fullagar, R; Wallis, LA; Faibairn, AS; Clarkson, C
    Archaeological research provides a long-term perspective on how humans live with various environmental conditions over tens of thousands of years. However, to do this, archaeologists rely on the existence of local and temporally comparable environmental proxies, which are often not available. Our research at Madjedbebe, a ~65,000-year-old archaeological site on Mirarr country in northern Australia, developed an on-site proxy for past rainfall from pandanus nutshell, a remnant of ancient meals eaten at the site. This talk will discuss how we can use ancient food scraps, such as pandanus nutshell, to document past rainfall and what the results of this research mean for communities living at Madjedbebe in the past.
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    Utilizing meteoric 10Be to define the mobile-stable regolith boundary within unconsolidated sediment
    (Australian Nuclear Science and Technology Organisation, 2021-11-17) Patton, NR; Shulmeister, J; Fujioka, T; Fink, D; Simon, KJ; Wilcken, KM
    Understanding the physico-chemical properties of soil profiles are fundamental to evaluate longterm landscape evolution in response to climate, tectonic and human activities. The thickness of the mobile regolith; the portion of the soil profile that is experiencing down slope movement, is a key parameter controlling soil production and erosion rates on hillslopes. However, delineating the interface between the mobile and stable boundary is difficult, specifically in thick (>1 m) unconsolidated sediment profiles. In this study we evaluate the utility of in situ and meteoric 10Be depth profiles to define the mobile-stable regolith boundary at the Cooloola Sand Mass coastal dune fields, Australia. Our results indicate a fairly uniform profile for in situ 10Be concentrations, suggesting the profile is largely dominated by inheritance thus not appropriate for this application. In contrast, meteoric 10Be concentration displays a humped profile, where the concentration significantly increases near the boundary of A(E)- and B-horizons. This observation is largely consistent with the qualitative field observation of the mobile-stable boundary. Despite these positive outcomes, however, it is still uncertain whether the observed meteoric 10Be soil profile reflects the mobile-stable boundary or other changes in physiochemical characteristics (e.g., bulk density, bioturbation, zone of illuviation). Consequently, work is being undertaken to test this approach on other dunes of varying ages (0.5, 2, 5, and 10 ka) in the same area that represent different soil maturity stages and thus variable degrees of physical/chemical evolution of soil profiles. If successful, the development of this new method will be utilized to quantify the mobile regolith layer, which can then be used to create mass balance models of soil erosion and deposition in landscape evolution studies. It will control an important, previously difficult to define parameter in soil production and erosion studies. © The Authors