Comparing interglacials in eastern Australia: a multi-proxy investigation of a new sedimentary record

dc.contributor.authorForbes, MSen_AU
dc.contributor.authorCohen, TJen_AU
dc.contributor.authorJacobs, Zen_AU
dc.contributor.authorMarx, SKen_AU
dc.contributor.authorBarber, Een_AU
dc.contributor.authorDodson, JRen_AU
dc.contributor.authorZamora, Aen_AU
dc.contributor.authorCadd, Hen_AU
dc.contributor.authorFranke, Aen_AU
dc.contributor.authorConstantine, Men_AU
dc.contributor.authorMooney, SDen_AU
dc.contributor.authorShort, Jen_AU
dc.contributor.authorTibby, Jen_AU
dc.contributor.authorParker, Aen_AU
dc.contributor.authorCendón, DIen_AU
dc.contributor.authorPeterson, MAen_AU
dc.contributor.authorTyler, JJen_AU
dc.contributor.authorSwallow, Een_AU
dc.contributor.authorHaines, HAen_AU
dc.contributor.authorGadd, PSen_AU
dc.contributor.authorWoodward, CAen_AU
dc.date.accessioned2021-06-29T04:36:32Zen_AU
dc.date.available2021-06-29T04:36:32Zen_AU
dc.date.issued2021-01-01en_AU
dc.date.statistics2021-06-11en_AU
dc.description.abstractThe widespread formation of organic rich sediments in south-east Australia during the Holocene (Marine Isotope Stage [MIS] 1) reflects the return of wetter and warmer climates following the Last Glacial Maximum (LGM). Yet, little is known about whether a similar event occurred in the region during the previous interglacial (MIS 5e). A 6.8 m sediment core (#LC2) from the now ephemeral Lake Couridjah, Greater Blue Mountains World Heritage Area, Australia, provides insight into this question. Organic rich sediments associated with both MIS 1 and 5e are identified using 14C and optically stimulated luminescence (OSL) dating techniques. Also apparent are less organic sedimentary units representing MIS 6, 5d and 2 and a large depositional hiatus. Sediment δ13C values (−34 to −26‰) suggests that C3 vegetation dominates the organic matter source through the entire sequence. The pollen record highlights the prevalence of sclerophyll trees and shrubs, with local hydrological changes driving variations in the abundance of aquatic and lake-margin species. The upper Holocene sediment (0–1.7 m) is rich in organic matter, including high concentrations of total organic carbon (TOC; 20–40%), fine charcoal and macrophyte remains. These sediments are also characterised by a large proportion of epiphytic diatoms and a substantial biogenic component (chironomids and midges). These attributes, combined with low δ13C and δ15N values, and C:N ratios of approximately 20, indicate a stable peat system in a swamp like setting, under the modern/Holocene climate. In comparison, the lower organic rich unit (MIS 5e-d) has less TOC (5–10%), is relatively higher in δ13C and δ15N, and is devoid of macrophyte remains and biogenic material. Characterisation of the organic matter pool using 13C-NMR spectroscopy identified a strong decomposition signal in the MIS 5e organic sediments relative to MIS 1. Thus the observed shifts in δ13C, δ15N and C:N data between the two periods reflects changes in the organic matter pool, driven by decompositional processes, rather than environmental conditions. Despite this, high proportions of aquatic pollen taxa and planktonic diatoms in the MIS 5e–d deposits, and their absence in the Holocene indicates that last interglacial Lake Couridjah was deeper and, or, had more permanent water, than the current one. ©2020 Elsevier Ltd.en_AU
dc.identifier.articlenumber106750en_AU
dc.identifier.citationForbes, M., Cohen, T., Jacobs, Z., Marx, S., Barber, E., Dodson, J., Zamora, A., Cadd, H., Franke, A., Constantine, M., Mooney, S., Short, J., Tibby, J., Parker, A., Cendón, D., Petersen. M., Tyler, J., Swallow, E., Haines, H., Gadd, P. & Woodward, C. (2021). Comparing interglacials in eastern Australia: a multi-proxy investigation of a new sedimentary record. Quaternary Science Reviews, 252, 106750. doi:10.1016/j.quascirev.2020.106750en_AU
dc.identifier.issn0277-3791en_AU
dc.identifier.journaltitleQuaternary Science Reviewsen_AU
dc.identifier.urihttps://doi.org/10.1016/j.quascirev.2020.106750en_AU
dc.identifier.urihttps://apo.ansto.gov.au/dspace/handle/10238/10947en_AU
dc.identifier.volume252en_AU
dc.language.isoenen_AU
dc.publisherElsevieren_AU
dc.subjectPollenen_AU
dc.subjectCharcoalen_AU
dc.subjectPeaten_AU
dc.subjectSedimentsen_AU
dc.subjectDiatomsen_AU
dc.subjectPlantsen_AU
dc.subjectStable isotopesen_AU
dc.subjectCarbon 14en_AU
dc.subjectLuminescenceen_AU
dc.subjectAustraliaen_AU
dc.titleComparing interglacials in eastern Australia: a multi-proxy investigation of a new sedimentary recorden_AU
dc.typeJournal Articleen_AU
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