Holocene lake-level fluctuations in Lakes Keilambete and Gnotuk, southwestern Victoria, Australia

• Published in: The Holocene
• Main Authors: Wilkins, Daniel, Gouramanis, Chris, De Deckker, Patrick, Fifield, L Keith, Olley, Jon
• Format: Article in Journal/Newspaper
• Language: English
• Published: SAGE Publications 2013
• Subjects: Paleontology; Earth-Surface Processes; Ecology; Archeology; Global and Planetary Change; ice core
• Online Access: http://dx.doi.org/10.1177/0959683612471983; http://journals.sagepub.com/doi/pdf/10.1177/0959683612471983; http://journals.sagepub.com/doi/full-xml/10.1177/0959683612471983

Reconstructed Holocene lake-level curves from two saline, hydrologically closed maar crater lakes in southwestern Victoria, Australia, show near synchronous lake-level changes throughout the Holocene. We show that lake levels, reconstructed from sediment particle size and ostracod valve chemistry (δ 18 O and Sr/Ca) have undergone rapid (<100 yr), large (>10 m) fluctuations throughout the Holocene. Finer sampling resolution shows a more sensitive response to Holocene climate than was previously presented for Lake Keilambete. Both maar crater lakes show a short-lived maximum in Holocene lake levels around 7.2 ka. The period of lake filling leading to peak lake levels matches the phase of most effective precipitation (7.4–7.0 ka) reconstructed from a high-resolution speleothem record from northern Tasmania. Water levels declined in both lakes during the mid Holocene, with a more substantive decline after ~5 ka which coincides with the end of the Southern Hemisphere hypsithermal. Water levels continued to oscillate with a periodicity of around 300–700 years, before reaching a late-Holocene nadir around 1.8 ka (Keilambete) and 1.3 ka (Gnotuk). The trend and periodicity of oscillations in the maar water levels show commonalities to δD in the Dome C ice core, and suggest that temperature may be a significant component in influencing the Precipitation/Evaporation (P/E) ratio in southeastern Australia during the Holocene.