Climates of the last three interglacials in subtropical eastern Australia inferred from wetland sediment geochemistry
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Date
2020-01-15
Journal Title
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Publisher
Elsevier
Abstract
Records of Australian climate during Marine Isotope Stages 5 and 7 (130–71 and 243–191 ka) are rare, preventing detailed assessments of long-term climate, drivers and ecological responses across the continent over glacial-interglacial timescales. This study presents a geochemistry-based palaeoclimate record from Fern Gully Lagoon on North Stradbroke Island (also known as Minjerribah) in subtropical eastern Australia, which records climates in MIS 7a–c, MIS 5 and much of the Holocene, in addition to MIS 4 (71–57 ka), and parts of MIS 6, MIS 3 and MIS 2 (191–130, 57–29 and 29–14 ka). Indicators of inorganic sedimentation from a 9.5 m sediment core – focussed on high-resolution estimates of sediment geochemistry supported by x-radiography, inorganic content and magnetic susceptibility – were combined with a chronology consisting of six radiocarbon (14C) and thirteen single-grain optically stimulated luminescence (OSL) ages. Hiatuses occurred at ~178–153 ka, ~36–21 ka and ~7–2 ka and likely result from the wetland drying. Low values of locally sourced aeolian materials indicate a wet MIS 7a–c and early MIS 6 before a relatively dry MIS 5. Inorganic flux during the Holocene was up to four times greater than during MIS 5, consistent with long-term interglacial drying observed in other regions, most notably in central Australia. This study highlights the importance of employing a combination of multiple dating approaches and calibrated geochemical proxies to derive climate reconstructions and to identify depositional complexities in organic-rich wetland records. © 2020 Elsevier B.V
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Keywords
X-ray fluorescence analysis, Geochemistry, Climates, Wetlands, Sediments, Quaternary period, Islands, Queensland, Australia
Citation
Kemp, C. W., Tibby, J., Arnold, L. J., Barr, C., Gadd, P. S., Marshall, J. C., McGregor, G. B. & Jacobsen, G. E. (2020). Climates of the last three interglacials in subtropical eastern Australia inferred from wetland sediment geochemistry. Palaeogeography, Palaeoclimatology, Palaeoecology, 538, 109463. doi:10.1016/j.palaeo.2019.109463