Chronostratigraphy of long lacustrine sedimentary records from Tasmania, Australia

• Main Authors: Lise-Pronovost, Agathe, Fletcher, Michael-Shawn, Simon, Quentin, Jacobs, Zenobia, Heslop, David, Blaauw, Maarten
• Format: Conference Object
• Language: English
• Published: 2019
• Subjects: /dk/atira/pure/sustainabledevelopmentgoals/climate_action; name=SDG 13 - Climate Action; Antarctic; Antarc*; ice core
• Online Access: https://pure.qub.ac.uk/en/publications/02ff4e6f-885a-4ca0-aebd-a43af2ff3408; https://agu.confex.com/agu/fm19/meetingapp.cgi/Paper/528712

Lake sediments can be sensitive recorders of environmental change on glacial-interglacial timescales; however, they are notoriously challenging to date. Here we present new chronological results of two lake sediment cores from western Tasmania (Australia) covering several glacial cycles: Lake Selina (5.5 m– ca. 265 ka) and Darwin Crater (61 m – ca. 800 ka). We aim to combine these two records within a common chronological framework to construct the longest continuous continental paleoclimate record from Australia. To do so, we employed absolute dating methods, including radiocarbon ( 14 C) and optically stimulated luminescence (OSL) dating, together with paleomagnetic and climatic correlations. Absolute dating methods were successfully applied to the uppermost and most recent part of the records. We find remarkable similarities at the millennial scale between Tasmanian lakes and Antarctic ice core climate records and we are exploring if shorter-term climate events could be shared between both records and thus used as additional relative dating points. We use two complementary geomagnetic field strength proxies, relative paleointensity (RPI) and atmospheric 10 Be cosmogenic radionuclides, to independently constrain the chronology within reliable intervals where environmental biases are minimal.