Holocene lake salinity changes in the Wimmera, southeastern Australia, provide evidence for millennial-scale climate variability

Justine Kemp, Lynda Radke, Jon Olley, Steve Juggins, Patrick de Deckker

Research output: Contribution to journalArticlepeer-review

27 Citations (Scopus)

Abstract

Palaeosalinity records for groundwater-influenced lakes in the southwest Murray Basin were constructed from an ostracod-based,weighted-averaging transfer function, supplemented with evidence fromCampylodiscus clypeu (diatom), charophyte oogonia, Coxiella striata (gastropod), Elphidium sp. (foraminifera), Daphniopsis sp. ephippia (Cladocera), and brine shrimp (Parartemia zietziana) faecal pellets, the δ18O of ostracods, and N130 μmquartz sand counts. The chronology is based on optically stimulated luminescence and calibrated radiocarbon ages. Relativelywet conditions aremarked by lower salinities between 9600 yr and 5700 yr ago, butmutually exclusive high- and low salinity ostracod communities suggest substantial variability in effective precipitation in the early Holocene. A drier climate was firmly in place by 4500 yr and is marked at the groundwater-dominated NW Jacka Lake by an increase in aeolian quartz and, at Jacka Lake, by a switch from surfacewater to groundwater dominance. Short lived, low-salinity events at 8800, 7200, 5900, 4800, 2400, 1300 and 400 yr are similar in timing and number to those recorded on Australia's southern continental shelf, and globally, and provide evidence for the existence of the ~1500-yr cycle in mainland southern Australia. We surmise that these are cool events associated with periodic equatorward shifts in the westerly wind circulation.
Original languageEnglish
Pages (from-to)65-76
JournalQuaternary Research
Volume77
Issue number1
DOIs
Publication statusPublished - 2012

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