1 Alexandra Cave, Naracoorte Caves World Heritage Area, South Australia. Credit: ABC South East SA: Isadora Bogle Athe AQUA PROGRAM AND ABSTRACT BOOKLET Adelaide 2022 1 A brief welcome from the organisers Nina Marni all to the biennial AQUA conference. It's very exciting to welcome so many people to Adelaide and to meet in person for the first time since 2018. Welcome, also, to those people joining online. It's lovely to think of seeing familiar faces once again. However, its particularly exciting that there is such a large number of student and early career researchers for whom this is their first AQUA meeting. Welcome and enjoy! There is a massive number of people who have contributed to this conference, often in ways that are unseen. I want to thank them enormously for their contributions. Please approach any of us if you have questions during the meeting. Looking forward to enjoying three fabulous days of Quaternary science. Associate Professor John Tibby (he/him/his) AQUA President and Organising Committee member on behalf of the organising committee: Lee Arnold, Tiah Bampton, Kym Edwards, Alexander Francke, Charlie Maxson, Vanessa Nowinski, Jon Tyler, John Tibby 2 AQUA 2022 Conference (6-8th December) program Monday night (5th December) 18:00 - 21:00 Icebreaker (with drinks and nibbles) Roxie’s Beer Garden. 182 Grenfell Street, Adelaide. http://www.roxies.com.au NB: There will be an opportunity to register at the ice breaker (but also at other times on Tuesday – see below) Day 1: Tuesday 6th December 8:00 -8:30 Registration Field Geology Room, Mawson Building NB: There will be an opportunity to register at morning tea 8:30 - 8:50 Welcome to country Mawson Lecture Theatre 8:50 -9:00 Conference opening Mawson Lecture Theatre 9:00 -9:30 Keynote Katharine Grant Abrupt change in North African hydroclimate and landscape evolution 3.2 million years ago? 9:30 -10:30 Session 1 - “People, Dust and Late Quaternary Environments” A Memorial Session for Dr Lynda Petherick, AQUA President 2018-2022 Mawson Lecture Theatre 9:30 -9:45 Rewi Newnham Antarctic black carbon whodunnit 9:45 -10:00 Sam Marx Linking distal dust deposits with proximal lake records within the Kati Thanda-Lake Eyre (KT-LE) Basin: Examining the environmental conditions http://www.roxies.com.au/ 3 responsible for Australian dust export and evaluating the role of aeolian processes in shaping KT-LE. 10:00 - 10:15 Kia Matley A multi-proxy record of environmental change at a glacial Nothofagus refugium, Wyelangta, Victoria 10:15 - 10:30 Patrick Moss Holocene Coastal Peatlands of the Tasmanian Wilderness World Heritage Area 10:30 - 10:45 Morning tea Sprigg Room 11:00 - 13:00 Session 2 - “Oceans and Coasts” Mawson Lecture Theatre 11:00 - 11:15 Vikki Lowe Water mass history of the Southwest Pacific through the last 160,000 years using radiolarians 11:15 - 11:30 Amy Prendergast Comparative sclerochronologies: evaluating gastropod shells and opercula as sea-surface temperature and seasonality archives for southeastern Australia 11:30 - 11:45 Colin V. Murray- Wallace Sea-level changes and coastal landscape evolution in south-eastern Australia during the Last Interglacial (MIS 5e) 11:45 - 12:00 Helen McGregor Millennial to seasonal scale views of El Niño-Southern Oscillation from central Pacific corals 12:00 - 12:15 Thomas Williams Circulation history of the deep Indian sector of the Southern Ocean since MIS 6 as revealed by εNd 12:15 - 12:30 Juliet Sefton Implications of anomalous relative sea-level rise for the peopling of Remote Oceania 12:30 - 12:45 Kotaro Shirai Reconstruction of past climate and its effects on environment, ecology, and ecosystem using long-lived bivalve shell. 12:45 - 13:00 Quan Hua Temporal variations in the marine radiocarbon reservoir effect during the Holocene – A review 4 13:00 - 14:00 Lunch Pizza Outside the Mawson Building 14:00 - 15:00 Lightning talks Mawson Lecture Theatre 14:00 - 14:05 Caroline Mather Holocene records of environment and freshwater availability from tufa archives: implications for human occupation at Murujuga, NW WA 14:05 - 14:10 Simon Connor A beginner’s guide to turning pollen data into estimates of vegetation cover 14:10 - 14:15 Chloe Stringer Window to past human-environment interactions? Preliminary results from a modern calibration study of freshwater mollusc species from the Central Murray River Basin 14:15 - 14:20 Felix Lauer Revisiting aeolian sediments in the Wagga Wagga region 14:20 - 14:25 Andrea Johansen High-resolution palaeodust archive from subantarctic Macquarie Island 14:25 - 14:30 Jonathan Tyler Palaeoclimate data and hydroclimate risk assessment: the role of archives, proxies and time 14:30 - 14:35 Zuorui Liu Investigations of Mammoth Teeth in Paleoenvironmental Reconstructions from Multiple Enamel Ridges 14:35 - 14:40 Harriet Magee Old flames: the relationship between cultural burring and fire histories on Gunaikurnai Country, Victoria 14:40 - 14:45 Sam Marx Reconstructing atmospheric particulate loads over the north-western Pacific Ocean during the mid to late Holocene: volcanism, dust and human perturbation of regional aerosol loads/composition. 14:45 - 14:50 Patrick Kennedy Fuel loads and fire: A palaeoecological analysis of long-term fire and fuel dynamics in Bundjalung National Park, New South Wales, Australia. 5 15:00 - 17:30 Poster session Sprigg Room Afternoon snacks served during poster session 16:00 – 16:30 17:30 CLOSE 17:45 - 19:00 Student and ECR event - Animals Anonymous and UniBar gathering Mawson Lecture Theatre and then Unibar NB: For those people not students and ECRs please find your own entertainment 6 Posters. *indicates a student poster which is eligible for a prize. Please vote for the best student poster using the slip provided Number and Author Title 1 Mahsa Alidoostsalimi * Unlocking seasonal variations in climate and Indigenous seasonal foraging practices associated with paleo-ENSO in Great Barrier Reef using marine gastropod shells as a paleoclimate archive 2 Kathryn Allen Spatiotemporal history of droughts and pluvials across eastern Australia's Natural Resource Management regions: a 600-year perspective. 3 Lee Arnold Examining sediment infill dynamics at Naracoorte Cave megafauna sites using multiple luminescence dating approaches 4 Kelsey Boyd * The potential of phytolith analysis in northern Australia. 5 Tomás Cortés Unveiling tsunami history on the Atacama Desert coast (northern Chile) using geological evidence and hybrid tsunami modelling 6 Bianca Dickson * Fossil pollen distributions in speleothems: an example from southwest Western Australia 7 Isabella Donato * Putting a Name to a Face: assessing the utility of geometric morphometrics on classifying the fossil varanids of Naracoorte Caves World Heritage Area. 8 Kym Edwards * Oxygen isotope ratios in plant phytoliths as a proxy for past climates and Environments 9 Alissa J Flatley Deciphering the role of terrigenous sediment supply for headwater channels in the Pilbara, WA 10 Alexander Francke Catchment vegetation and erosion controls soil carbon cycling in SE Australia during two Glacial-Interglacial complexes 11 Manoshi Hazra * The assembly of plant microfossil assemblages: Characterizing pollen and phytoliths from plants and soils to improve palaeoecological interpretations 12 Molly Husdell * Development of the Great Barrier Reef from the Last Glacial Maximum to present 13 Alysha Jones * A Late Quaternary low-angle fan-delta complex, Lake George, NSW. 14 Justine Kemp Late Quaternary river terrace development in subtropical Australia: climate change and human occupation 15 Alena Kimbrough Validation of glacial-interglacial rainfall variations in southwest Sulawesi using Mg/Ca and δ18O in speleothems 7 16 Sam Marx Reconstructing atmospheric particulate loads over the north-western Pacific Ocean during the mid to late Holocene: volcanism, dust and human perturbation of regional aerosol loads/composition. 17 Fletcher Nixon Clumped isotope analysis of central Australian carbonates: A potential palaeoclimate proxy for Australia’s arid interior 18 Ryan North * Historic imagery reveals magnitude of glacier response to ice shelf debuttressing in the Larsen B Inlet, Antarctica 19 Vanessa Nowinski * East Asian Monsoon response to abrupt global change during the last glacial period: evidence from the sediments of Lake Suigetsu, Japan. 20 Corey Port * The timing of Termination IX in Italian lake sediments: a test of orbital theory 21 Juliet Sefton A new Holocene sea-level database for Australia 22 Adrian Slee Landslides and periglacial deposits in Northern New England provide evidence of past climate. 23 Yanjie Tian * Environmental and Climate Controls on Late Quaternary Landscape Evolution along the Central Murray River, Australia 24 Lina Toben * A 1000-year isotope-based record of climate variability inferred from the sediments of Lake Yukidori, East Antarctica 25 Nerita Turner * Bite at the end of the tunnel: a quantitative literature review of the taphonomic effects of marsupial carnivores from Pleistocene Australia 8 Day 2: Wednesday 7th December 8:15 OPEN 8:30 -9:00 Keynote Kale Sniderman Uniformitarianism's epic fail: the glacial aridity paradigm 9:00 -10:00 Session 3 - “The past two thousand years of hydroclimate: from mean states to climate extremes” Mawson Lecture Theatre 9:00 -9:15 Pauline Treble Speleothem ‘uptick’ supports reduction in rainfall recharge to groundwater is unprecedented for last 800 years, SW Western Australia 9:15 -9:30 Tim Cohen Extreme pluvials over the last two millennia detected using ephemeral lakes 9:30 -9:45 Sophie Grunau Climate extremes recorded in playa lakes across continental Australia 9:45 -10:00 Maame Adwoa Maisie Investigating the links between recent fire events and the accumulation and characteristics of charcoal in Temperate Highland Peat Swamps in the Blue Mountains of NSW 10:00 - 10:30 Morning tea Sprigg Room 10:30 - 12:30 Joint session with the Australian Archaeology Association (Darwin) Session 4 - Human-Environment Interactions Mawson Lecture Theatre (in person) 10:30 - 10.50 Michael Westaway Investigating the Multi-Regional Emergence of Social and Economic Complexity Across Diverse Australian Environments 10:50 - 11:10 Ben Shaw Human-Environment Interactions in the Far Eastern New Guinea Islands (Massim Region) Since the Last Glacial Maximum 11:10 - 11:30 Racheal Minos Geomorphological Processes and Post-Depositional Movement on Stony Rises in Wurundjeri Country, Victoria 9 11:30 - 11.50 Lauren Cunningham The Use of High-Magnification Microscopy in Identifying the Impacts of Carnivores in Faunal Assemblages 11:50 - 12:10 Vito Hernandez The Microstratigraphy of Tam, Pà Ling Cave, Laos: Situating Early Humans Within the Changing Tropical Environment 12:10 - 12:30 Jonathan Benjamin Recent Developments from the Submerged Cultural Landscape of Murujuga Sea Country, Northwest Shelf (Dampier Archipelago), Western Australia 12:30 - 13:30 Lunch Sprigg Room OCTOPUS data base Mawson Lecture Theatre 13:30 - 15:30 Joint session with the Australian Archaeology Association (Darwin) Session 5 - Human-Environment Interactions Mawson Lecture Theatre (in person) 13:30 - 13.50 Rachel Popelka-Filcoff ARCAS State of the Art: Archaeological Science in Australasia in 2022 13:50 - 14:10 Jessica Gibbs Perched Springline Tufas Reveal a Warm-Wet Palaeoclimate for First Australians on the Late Quaternary Darling Downs, Southeast Queensland 14:10 - 14:30 Haidee Cadd (in person) Proxies, Models, and People: Using Transient iTrace Climate Models to Disentangle Proxy and Archaeological Records During the Penultimate Deglacial in Australia 14:30 - 14.50 Emma Rehn (in person) SahulArch: Age Determinations for Archaeological Sites from Sahul in the OCTOPUS Database 14:50 - 15:10 Rachel Rudd (in person) Kimberley Monsoon Rainforests: New Holocene Palaeoenvironmental Records from Northwestern Australia 10 15:10 - 15:30 Meghan McAllister (in person) Preservation Prevails at Tam Pà Ling, Laos: Reconstructing Palaeovegetation Dynamics via Higher Plant Biomarkers Offer New Insights into Environmental Variability Across MIS 3-MIS 1. 15:30 - 16:00 Afternoon tea Sprigg Room 16:00 - 17:30 Session 6 - “New insights into abrupt climate changes, tipping points and major transitions throughout the Quaternary” Mawson Lecture Theatre 16:00 - 16:15 Alexander Francke East Asian Monsoon dynamics in Japan as inferred from the sediments of Lake Suigetsu 16:15 - 16:30 Ellen Corrick Characterising the expression of sub-millennial scale climate events in western Europe during the early last glacial period using multi-proxy speleothem records 16:30 - 16:45 William Henriquez Gonzalez Synchronous onset of the last glacial termination in the southern mid- latitudes 16:45 - 17:00 Helen Bostock The Mid-Pleistocene Transition in the Southwest Pacific 17:00 - 17:15 Russell Drysdale Last Interglacial cooling in New Zealand and its potential link to a West Antarctic meltwater pulse 17:15 - 17:30 Khairun Nisha Mohamed Ramdzan Insights for restoration: Reconstructing the long-term responses, resilience and recovery time of vegetation, hydrology and peat condition to fire events in the Sebangau peatland, Central Kalimantan. 17:30 CLOSE 19:00 Conference Dinner: Belgian Beer Café Belgian Beer Café, 27/29 Ebenezer Place, Adelaide 11 Day 3: Thursday 8th December 8:15 OPEN 8:30 -9:00 Keynote Kathryn Allen Summer and winter flow records for Tasmania derived from a local tree-ring network 9:00 -10:30 Session 7 - “Humans and ecosystems” Mawson Lecture Theatre 9:00 -9:15 Micheline Campbell Towards the development of fire proxies in speleothems using geochemical signatures in ashes from bushfires 9:15 -9:30 Anthony Romano Adding fuel to the fire: have fires in southeast Australia always burned so hot? 9:30 -9:45 Rebecca Ryan Developing Novel Techniques for Reconstructing Past Fire Histories in South-Eastern Australia 9:45 -10:00 Sarah Cooley Response, resilience and recovery of Tasmania’s endangered Pencil Pine using a multi-archive palaeoenvironmental record 10:00 - 10:15 Lucinda Duxbury Lake sedimentary ancient DNA reveals ecosystem response to fire and climate on Kangaroo Island (Karti), Australia 10:15 - 10:30 Michael Fletcher Clear and Present Danger: the pure state of ignorance that has led to Australia’s bushfire crisis 10:30 - 11:00 Morning tea Sprigg Room 11:00 - 12:45 Session 8 - “Humans and ecosystems, Climate and the Cryosphere” Mawson Lecture Theatre 11:00 - 11:15 Scott Mooney Simple and fast methods for sediment-based quantification of macroscopic charcoal: solutions to recently identified problems 12 11:15 - 11:30 Johanna Hanson Late Holocene environmental change of Te Whakaraupō | Lyttelton Harbour, New Zealand 11:30 - 11:45 Michael Reid Sediment records suggest post British-invasion declines in diversity of wetland plant communities in the Koondrook-Perricoota Forest, Murray River, NSW 11:45 - 12:00 Jess Macha Using ice core records to understand interannual -multidecadal trends in Antarctic Ice Sheet surface mass changes 12:00 - 12:15 Charles Maxson A Holocene subtropical hydroclimate reconstruction from Karboora (Blue Lake), Minjerribah, Queensland 12:15 - 12:30 Asika Dharmarathna A detailed study of Holocene climate variability in south-east Australia based on cellulose inferred lake water isotopes and monitoring and modelling approach at Lake Surprise, western Victoria. 12:30 - 12:45 Patrick De Deckker The Holocene hypsithermal in the Australian region 12:45 - 13:00 Special presentation and student poster prize presentation Ms Michelle Durant, Managing Director of Australian Institute of Nuclear Science and Engineering AINSE opportunities for postgraduate students and early career researchers 13:00 - 14:00 Lunch Sprigg Room Poster session redux. We encourage poster authors to stand with their posters this lunch time 14:00 - 16:00 Session 9 - Climates and Humans Mawson Lecture Theatre 14:00 - 14:15 Calla Gould-Whaley Last Glacial pluvial periods evident in subaqueous speleothems from Australia’s southern arid-margin 13 14:15 - 14:30 Mohammad (Sepehr) Akhavan Kharazian First geoarcheological study of a Palaeolithic site on the northern edge of the Iranian Central Desert: Mirak (Semnan, Iran) 14:30 - 14:45 Nathan Jankowski Willandra Lakes re-revisited: preliminary results from Lake Arumpo, NSW 14:45 - 15:00 Peter D. McIntosh Ancient shorelines of northwest Tasmania – a preliminary report 15:00 - 15:15 Timothy Barrows The age and origin of block deposits in the Victorian Alps, Australia 15:15 - 15:30 Bohao Dong Using giant clam shell geochemistry to understand past environmental change and human-environment interaction in the South Pacific 15:30 - 15:45 Cesca McInerney Straight from the kangaroo’s mouth: A quantitative relative humidity proxy 15:45 - 16:00 Louisa Sheridan Tracking an anomaly: a MIS 6 warming event in Tasmania, Australia. 16:00 - 16:30 Afternoon tea Sprigg Room 16:30 - 17:30 Session 10 - Varied (but exciting!) talks Mawson Lecture Theatre 16:30 - 16:45 Richard Jones Stability of the Antarctic Ice Sheet during the pre-industrial Holocene 16:45 - 17:00 Teresa Dixon Monsoonal variations in the Kimberley since human arrival – clues from new palaeoenvironmental records 17:00 - 17:15 Tiah Bampton Palaeodiet of Quaternary fossil rodents from Naracoorte Caves: implications for extinction and conservation 17:15 - 17:30 Rieneke Weij Speleothem U-Th-Pb dating, pollen and charcoal reveal cave antiquity and fossil accumulation window at the Naracoorte Caves 17:30 Conference close and presentation of awards 18:30 Quiz night Unibar 14 Day 4: Friday 9th December Field trip to the Coorong, lower lakes and Coorong coastal plain Depart 8:00 am Victoria Drive (C-9) on the map below Return 6:00 pm to the same location NB: More details provided at the conference 15 Length of presentations Full length oral presentations: 12 min speaking time and 3 min for questions Lightning presentations: 5 min (ideally 4 min with time for one question and answer) Poster size and orientation Posters should be no larger than A0 size (i.e. 841 x 1189 mm) and be oriented in Portrait format. Student poster and talk prizes Thanks to the generous sponsorship of both AINSE and UNSW’s CHRONOS 14Carbon-Cycle Facility there are prizes for the best student talks and posters. Prizes will be awarded in honour of our late colleague Dr Lynda Petherick, AQUA President 2018-2022. Venue locations – external Icebreaker: Roxie’s Beer Garden. 182 Grenfell Street, Adelaide. www.roxies.com.au. Dinner: Belgian Beer Café, 27/29 Ebenezer Place, Adelaide. www.oostende.com.au http://www.roxies.com.au/ file:///C:/Users/Kym/AppData/Local/Microsoft/Windows/INetCache/Content.Outlook/5EWZMOMP/www.oostende.com.au 16 Venue locations – University of Adelaide Mawson Lecture Theatre– Ground Floor Mawson Building, University of Adelaide (B-13) Sprigg Room – First Floor Mawson Building, University of Adelaide (B-13) Unibar – Ground floor, Union House, University of Adelaide (E-7) Mawson Building Unibar (Union House) 17 OCTOPUS Workshop Wednesday lunchtime, Mawson Lecture Theatre Dr Emma Rehn (James Cook University) and Dr Haidee Cadd (University of Wollongong) OCTOPUS is an open-access database of age determinations and denudation rates from archaeological, sedimentary, fossil, and glacial archives. OCTOPUS’ core collections are currently SahulArch (archaeological 14C, OSL, and TL-derived ages), SahulSED (sedimentary OSL and TL-derived ages) and CRN (10Be and 26Al-derived catchment-averaged denudation rates). In 2023, OCTOPUS core collections will expand to include charcoal data from sedimentary archives (SahulCHAR), and 14C dates from sedimentary archives (within SahulSED). OCTOPUS database centralises data gathered from a broad array of sources, including published works and grey literature, which were lacking consistent reporting standards. OCTOPUS standardises these data with detailed metadata fields specific to each sub-collection. Data collection standards were determined through community input and expert advice for each dating method. OCTOPUS provides homogenised, curated datasets containing relevant metadata that can be used by researchers for a range of applications such as review, modelling, and assessment of chronometric robustness. The database is cloud-based and open access, meaning users can access data via a web interface or directly through software such as QGIS or R using the Web Feature Service. This workshop will introduce participants to the OCTOPUS core collections and provide an interactive walk-through of accessing data through OCTOPUS via the web interface and Web Feature Service. The workshop is also an opportunity for open discussion, and feedback from the AQUA community, on how best to support the community to use and update OCTOPUS, and on the development of SahulCHAR. To access the OCTOPUS web interface, visit https://octopusdata.org/ For more information on OCTOPUS visit:https://epicaustralia.org.au/resource/octopus/ https://octopusdata.org/ file:///C:/Users/Kym/AppData/Local/Microsoft/Windows/INetCache/Content.Outlook/5EWZMOMP/https/epicaustralia.org.au/resource/octopus/ 18 With thanks to our generous sponsors CHRONOS 14Carbon-Cycle Facility (UNSW) 19 ABSTRACTS Key note speakers Summer and winter flow records for Tasmania derived from a local tree- ring network Allen, Kathryn1; Verdon-Kidd, Danielle2; Willis, Mark 3; Maxwell, Carolyn3; Baker, Patrick4 1 University of Tasmania; 2University of Newcastle; 3 Hydro Tasmania; 4 University of Melbourne To address questions around the availability of water resources into the future for renewable energy generation (a key focus for Tasmania) requires an awareness of past variability. Short term instrumental records are highly unlikely to represent the true range of natural variability in systems. We have developed four tree-ring based long flow records, two for western Tasmania and two for northern Tasmania. The summer (DJF) reconstructions extend over the past millennium while the winter (JA) reconstructions cover the past 450 years. According to the reconstructions, the north and west of the state experienced a very strong pluvial event in the 11th century, and severe and prolonged dry conditions from the late 15th to mid 16th century. The western summer reconstructions indicate that summers over the past century have generally been slightly drier than over much of the past millennium (late 15th-16th century excluded). Although very similar to one another there are important differences between the northern and western summer reconstructions around 1300 CE, middle of the 15th Century and latter part of the 20 18th Century. The winter reconstructions suggest that the most recent decades, especially in the north, have been steadily drying and are relatively unusual in the 1450-year context. The differences amongst the reconstructions highlight the importance of teasing out regional differences in our hydroclimate history, especially when 'high yield' dams are located in the central north of the state at higher elevations than typically much larger catchments in western Tasmania. 21 Abrupt change in North African hydroclimate and landscape evolution 3.2 million years ago? Grant, K.M.1; Amarathunga, U.1; Amies, J.D.1†; Hu, P.1; Qian, Y.1; Penny, T.1; Rodriguez-Sanz, L.1; Zhao, X.1; Liebrand, D.2; Hennekam, R.3,4; Westerhold, T.5; Gilmore, S.6; Lourens, L.J.4; Roberts, A.P.1; Rohling, E.J.1,2 1 Research School of Earth Sciences, Australian National University, Canberra; 2 University of Southampton, National Oceanography Centre, UK; 3 NIOZ Royal Netherlands Institute for Sea Research, Department of Ocean Systems, The Netherlands; 4 Department of Earth Sciences, University of Utrecht, The Netherlands; 5 MARUM, University of Bremen, Germany; 6 Geoscience Australia, Canberra; †Now at The Met Office, FitzRoy Road, Exeter EX1 3PB, United Kingdom On orbital timescales, North African climate variability is characterised by Green Sahara Periods (GSPs) alternating with more arid periods. GSPs correspond to minima in Earth’s orbital precession cycle and boreal summer insolation maxima, resulting in a more northerly and intensified African rainbelt. Reconstructing the timing and intensity of GSPs is therefore important for understanding past changes in Earth’s albedo, land-vegetation feedbacks, and hominin migrations. However, there are few continuous, well-dated records of GSPs that extend beyond the Pleistocene. Here, we present the first continuous, astronomically dated GSP record back to 5.2 Ma from Eastern Mediterranean Ocean Drilling Program (ODP) Site 967, based on Ba/Al, Ti/Al, and planktic 18O. From the same site, we also present records of Saharan dust and riverine inputs, based on environmental magnetic and scanning x-ray fluorescence records, which have been converted into element concentrations by multivariate log-ratio calibration. We find that wind-blown dust inputs 2 Sourced from https://earthsciences.anu.edu.au/ 22 increased sharply ~1.2 Myr ago, when global ice-ages intensified, whereas fluvial terrigenous inputs doubled abruptly 3.2 Myr ago, at the same time as a fundamental change in sapropel development. We evaluate different hypotheses (climatic vs tectonic) to explain this dramatic 3.2 Ma shift, and deduce that it likely indicates an abrupt state-transition to expanded Saharan aridity with extreme North African arid:humid variability. We further surmise that this critical North African landscape transition was in response to a global climate state-shift to icehouse conditions, as the timing closely coincides with the onset of intensified northern hemisphere glaciation. Preliminary simulations with the fully coupled GFDL CM2.1 climate model support our inferences. 23 Uniformitarianism's epic fail: the glacial aridity paradigm Sniderman, Kale 1; Weij, Rieneke2; Hellstrom, John1; Woodhead, Jon1 1 University of Melbourne, Parkville, Victoria, Australia; 2 University of Cape Town, Cape Town, South Africa For the past ~half century, the climate of the Last Glacial Maximum has usually been interpreted as substantially drier than today, in most low- to mid-latitude regions. This interpretation has been based largely on evidence from fossil pollen, indicating reduced vegetation biomass and/or treelessness, along with evidence of higher dust deposition rates and, in Australia, mobilisation of currently-stable sand dunes. However, there is an increasing understanding that the ‘arid’ character of LGM vegetation is partly an artefact of C3 plants’ reduced water-use efficiency under low atmospheric CO2. Nevertheless, LGM vegetation, and dust- and dune-based indicators, continue to be widely interpreted as self-evidently indicating arid LGM climates. In Australia, speleothems don’t strongly support a glacial aridity paradigm, and may contradict it, where they clearly grew through the LGM. Nevertheless, evidence of speleothem growth during the Late Pleistocene has so far had little influence on narratives of LGM climate. U-Th-dated speleothem palynology – the analysis of fossil pollen preserved within speleothems – can permit the development of vegetation and climate records supported by firm radiometric age models, which may allow detailed interrogation of LGM hydroclimate even in regions where ‘conventional’ wetland-based palynology has failed for lack of suitable sediments, or is uninformative because the pollen records are typically dominated by a small number of widespread plant taxa. Here, I will present new LGM speleothem pollen records from Naracoorte (South Australia) and Weelawadji caves (Western Australia). Both records show an expected, substantial 24 reduction in LGM vegetation biomass, but the presence of moisture-demanding taxa also demonstrates that current biomes persisted, rather than being replaced by more arid- adapted biomes. Quantitative reconstructions indicate that climatic moisture availability was similar to or higher than today, inconsistent with the idea of heightened LGM aridity. 25 Oral presentations First geoarcheological study of a Palaeolithic site on the northern edge of the Iranian Central Desert: Mirak (Semnan, Iran) Akhavan Kharazian, Mohammad 1; Jamet, Guillaume 2 ,3; Puaud, Simon 4; Vahdati Nasab, Hamed5; Hashemi, Milad 5; Guerin, Guillaume 6; Heydari, Maryam 6; Bahain, Jean- Jacques 4; Berillon, Gilles 4 1School of Geography, Earth and Atmospheric Sciences, University of Melbourne, Melbourne, Australia; 2GéoArchÉon Viéville-sous-les-Côtes, France; 3UMR 8591 Laboratoire de Géographie Physique Pierre Birot CNRS-Université Paris 1, Meudon, France; 4UMR7194 HNHP MNHN-CNRS-UPVD / Département Homme et Environnement, Musée de l'Homme, Paris, France; 5Department of Archaeology, Tarbiat Modares University, Tehran, IRAN ; 6UMR 5060 IRAMAT-CRP2A / Université Bordeaux Montaigne, Maison de l'Archéologie, Pessac, France Mirak is a Palaeolithic site in Iran comprising several localities (“mounds”) scattered over a floodplain extending from the southern foothills of the Alborz Mountains to the northern edge of the Central Desert in the Semnan area. The area was studied by a team of Iranian- French researchers between 2015 and 2017. The geoarchaeological excavations carried out at the Mirak N°8 mound uncovered a 7 m-thick pedo-sedimentary section, in which two sequences corresponding to different depositional environments have been observed. Sequence I, comprising alternating horizons of poorly pedogenised clayey silt intercalated with sand layers, is interpreted as an alluvial pedo-sedimentary body deposited in an active floodplain during the Late Pleistocene, periodically interrupted by shallow sheet flooding deposits. According to the stratigraphy and OSL dating there is an extended sedimentary hiatus before the occurrence of sequence II which corresponds to calcareous aeolian deposits typical of a desert environment. The Mirak N°8 deposits were affected by several 26 stages of incipient aridisol formation with features implying a gradually increasing prevalence of more arid conditions. The Mirak N°8 was deposited from the Late Pleistocene to the Late Holocene (52ka to 0.4ka) and within it several distinct upper Palaeolithic levels were detected, and the most recent level is most likely made up of palimpsests resulting from repeated human occupations. Elemental analyses show a homogenous mineralogy throughout the record regardless of the type of depositional regime, suggesting a local polygenic provenance. Both alluvial and aeolian accumulations were subjected to post-depositional pedogenesis processes indicated by pedofeatures characteristic of calcareous, gypsiferous aridisols (Bk, By). Colour differences between the two sequences at Mirak N°8 can be attributed to deposition in environments with varying oxidation/reduction conditions, presumably related to higher groundwater levels, especially for the units deposited during the late Pleistocene as opposed to the generally warm and dry conditions of the Holocene. 27 Palaeodiet of Quaternary fossil rodents from Naracoorte Caves: implications for extinction and conservation Bampton, Tiah1; Reed, Elizabeth1,2; Arnold, Lee3; DeSantis, Larisa4,5 1 Department of Ecology and Evolutionary Biology, The University of Adelaide, SA 5005, Australia; 2 Earth and Biological Sciences, South Australian Museum, Adelaide, SA, 5000, Australia; 3 Department of Earth Sciences, The University of Adelaide, SA 5005, Australia; 4 Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee, 37240, United States; 5 Department of Earth and Environmental Sciences, Vanderbilt University, Nashville, Tennessee, 37240, United States. Understanding the dietary and habitat niche of past faunas is important for elucidating faunal community response to changes in climate and environment through time. Stable isotopic analysis of carbon (ẟ13C) and oxygen (ẟ18O) obtained from fossil remains is a useful tool for interpreting palaeoecology of both extinct and extant fauna. Here we report on a community stable isotope study of Quaternary fossil vertebrates from the Naracoorte Caves World Heritage Area (NCWHA). We conducted ẟ18O and ẟ13C analyses on fossil teeth of two native rodent species (Pseudomys auritus and P. australis), obtained from a palaeontological excavation in the third chamber of Blanche Cave (5U6). P. auritus became totally extinct shortly after European colonisation; probably in the 1850s. Consequently, little is known of its diet or habitat preference. We analysed ẟ13C and ẟ18O from the bioapatite of fossilised tooth material, using isotope ratio mass spectrometry. Isotopic signatures from ẟ13C and ẟ18O were used to reconstruct palaeodiet and drinking behaviour for both species. These data were then compared with existing ecological records. A sample of modern P. australis was also analysed and compared to the data. The ẟ13C data show that P. auritus was more of a dietary specialist when compared to P. australis. While the ẟ18O indicate that the two species obtained their body water from a similar source. The modern P. australis shared the same diet between fossil and modern with a difference in δ18O values. Our results suggest the key driver of extinction for P. auritus may have been habitat loss and degradation through land clearing and livestock grazing. Predation by feral cats compounded this impact. Understanding the diets of extinct and extant species present in Naracoorte fossil 28 deposits has useful applications for modern conservation and reintroduction of species regionally. 29 The age and origin of block deposits in the Victorian Alps, Australia Barrows, Timothy T 1,2; Mills, Stephanie C 1; Fifield, L. Keith 3 1 School of Earth and Environmental Sciences, University of Wollongong; Wollongong 2 School of the Environment, Geography & Geosciences, University of Portsmouth, Portsmouth, UK; 3Research School of Physics, The Australian National University, Canberra Pleistocene glaciation was restricted in Australia to only the highest parts of the Snowy Mountains and Tasmania. However, periglacial activity was much more widespread. Periglacial landforms can be found down to 600 m in the Southern Tablelands and lower than this further to the south. Block deposits in the form of blockstreams and block slopes become common at higher elevations. The form and size of these deposits varies widely and their mode of formation is enigmatic. In Victoria, large-scale deposits occur above 900 m in the Mt Hotham region. In this talk we will describe the morphology of these deposits and their surface architecture. 3D modelling supports the idea that pits in the surface are ice segregation features. We present new exposure ages for blocks in these deposits using the cosmogenic nuclides 36Cl and 10Be. The re-establishment of forest at the end of the Pleistocene in the area is dated using radiocarbon. Weathering rind analysis is used on several deposits to explore its utility as a relative dating tool in the region. Lastly, based on modern analogues, we estimate that mean temperatures were at least 8 °C colder than at present when the deposits formed. 30 The Mid-Pleistocene Transition in the Southwest Pacific Helen Bostock1; Ben Houseman1; Patrick Moss; Gavin Dunbar 2; Joel Pedro3; Molly Husdell1; Kim Baublys1; Luna Walther1 1 School of Earth and Environmental Sciences, University of Queensland; 2 Antarctic Research Centre, Victoria University Wellington; 3Australian Antarctic Division A Mid-Pleistocene Transition (MPT) in global climate is evident from a shift in the frequency and characteristics of glacial-interglacial cycles, from small amplitude symmetrical 41 kyr cycles to large amplitude asymmetrical 100 kyr cycles starting around 1.2 Ma. The reason for this shift is highly debated as there is no change in the long-term pattern of insolation at this time. There are several hypotheses for this transition including (and not mutually exclusive); enhanced CO2 removal from the atmosphere; coeval timing of ice sheet expanse in the northern and southern hemisphere, deep ocean cooling and reduced ventilation in the Southern Ocean; and intensification of the tropical Pacific Ocean/atmosphere circulation. To provide context for the Million Year Ice Core (MYIC) project that is being drilled at Little Dome C in East Antarctica over the next few years, we have developed two new Tasman Sea marine oxygen stable isotope records from Lord Howe Rise (DSDP591A) and east of Tasmania (ODP1172). We have also compiled the existing data covering the last 1.2 Myrs from marine cores from the Southwest Pacific Ocean. Previous work largely focussed on sea surface temperature (SST) changes as the MPT evolved. These studies found a large increase in the glacial/interglacial SST amplitude across the subtropical front These data suggest there were broader changes in circulation in the Southwest Pacific across the MPT transition. These surface water oceanographic changes would have had a major influence on the climate of the region as indicated by pollen evidence from the marine cores. There is also evidence for a major benthic foraminifera extinction across this time period. Although the reason for this extinction is unknown, it may have been linked to changes in the deep-water characteristics and circulation or to a change in biological productivity. 31 Towards the development of fire proxies in speleothems using geochemical signatures in ashes from bushfires Campbell, Micheline 1; McDonough, Liza2; Naeher, Sebastian3; Treble, Pauline2,1; Grierson, Pauline4; Sinclair, Dan5; Howard, Daryl6; Baker, Andy1,2 1 UNSW Sydney; 2 ANSTO; 3 GNS Science; 4 The University of Western Australia; 5 Victoria University of Wellington; 6Australian Synchrotron, ANSTO Our knowledge of past fire regimes is limited by short observational records. Proxy archives (such as sediment cores, ice cores, speleothems, and tree scars) are used to extend these records and develop a better understanding of past fire regimes. Recently, stalagmites (i.e., cave deposits), have been shown to record past fire events, and it is possible that they include other attributes of the fire regime (e.g. burn severity). Stalagmite fire proxies are both chemical (e.g. oxygen isotope composition of calcite, and nutrient and trace metal concentrations), and physical (e.g. growth rate, fabric). Trace metals and nutrients are leached from ash and subsequently transported to the stalagmite via hydrological pathways. We collected ash from four Australian karst sites which experienced fires in recent years (2019 and 2022). Ash chemical composition was determined by analysis of leachates (inorganic chemistry) and by analysis of the ash itself (organic biomarker concentrations of a subset of the ash dataset). The concentrations of inorganic components (e.g. of trace metals strontium and magnesium) show a clear difference between more- and less-combusted materials, as inferred by ash colour. Common fire biomarker concentrations (e.g. polycyclic aromatic hydrocarbons and levoglucosan) showed no clear relationship with inferred burn severity. Together, this has implications for the use of both organic and inorganic fire proxies in stalagmites and other sedimentary proxy archives. Inorganic ash geochemistry results will be used to contextualise changes in stalagmite geochemistry from Western Australian stalagmites (as measured by LA-ICP-MS and 32 Synchrotron micro-XFM) which experienced bushfires during the satellite era. We aim to determine whether stalagmite chemistry can be used as a proxy for burn severity. 33 Extreme pluvials over the last two millennia detected using ephemeral lakes Cohen, Tim1; Rui, Xue2; Goodwin, Ian3; Armon, Moshe4; Enzel, Yehouda5; Grunau, Sophie1; May, Jan-Hendrik6; Marx, Sam1; Mogensen, Laura1; Carvalho, Rafael7 1 School of Earth, Atmospheric and Life Sciences, University of Wollongong; 2 College of Earth Sciences, Jilin University, Changchun, China; 3 Climalab; 4 ETH Zurich; 5 The Hebrew University of Jerusalem; 6 The University of Melbourne; 7 Deakin University The Australian continent is characterised by thousands of ephemeral lakes that only fill after extreme (daily or seasonal maxima) rainfall conditions. Many have little to no contributing/catchment area, while others drain up to one seventh of the continent (e.g. Kati Thanda-Lake Eyre [KT-LE], draining 1.14 M km2). Here we use ephemeral lakes from diverse moisture sources across the Australian continent and with catchment areas varying over three orders of magnitude to reconstruct past pluvial phases over the last two millennia. We present preliminary chrono-stratigraphic data of beaches/palaeoshorelines that are all at or above the modern maximum, therefore representing extreme runoff conditions. Such landforms represent unambiguous evidence of pluvials that have occurred over the last 2000 years. Data from Lake Woods (Northern Territory), Kati Thanda-Lake Eyre, Lake George (NSW) and Lake Buchanan (Queensland) are discussed with the aim of assessing recurrence intervals for such wet extremes. These sedimentary archives, whilst discontinuous, add to the capacity to evaluate late Holocene climate change within context of the observational record. 34 Response, resilience and recovery of Tasmania’s endangered Pencil Pine using a multi-archive palaeoenvironmental record Cooley, Sarah1; Fletcher, Michael-Shawn1; Drysdale, Russell 1 1 School of Geography, Earth & Atmospheric Sciences, University of Melbourne, Melbourne The Tasmanian Wilderness World Heritage Area (TWWHA) is home to globally significant and highly valued flora with ancestries in the supercontinent of Gondwana. Anthropogenic climate change is shifting baseline conditions and increasing pressures on long-lived palaeoendemic tree species directly via increasing temperatures and aridity across southeast Australia and indirectly via increased frequency of lightning-ignited wildfires. During the summer of 2016 over 80 wildfires were ignited across the Central Plateau decimating stands of Gondwanan refuge in TWWHA, severely threatening core refugia of extremely fire-sensitive palaeoendemic conifer Athrotaxis cupressoides (Pencil Pine). Despite significant funding to manage these threatened Tasmanian/Lutruwitan ecosystems, the long-term impact of climate change (and other factors) on the resilience of these systems remains poorly understood. Thus, there is a lack of understanding of how to apply the most efficient, impactful and cost-effective management strategy. Here, there is a need to develop a deep, long-term understanding of these long-lived ecosystems to execute well- informed land-management strategies for their future preservation. This project takes a multi-proxy approach by applying both palaeoecological and geochemical analysis techniques on organic sediments extracted from lake and bog sites across the Central Plateau (Lutruwita) in conjunction with high-resolution palaeoclimatological speleothem analysis performed on a stalagmite section collected from nearby Kubla Khan Cave (Mole Creek). This ongoing research will provide a detailed multifaceted understanding of how historical species composition, fire regime and moisture variability has influenced the response, resilience and post-fire recovery of Pencil Pine dominated systems across the Central Plateau throughout the Holocene (ca ~11.7 kyrs to 35 present). Such findings aim to facilitate a holistic understanding of how best to target management efforts to preserve highly threatened Pencil Pine, and similar long-lived fire- sensitive ecosystems in the wake of the climate crisis. 36 Characterising the expression of sub- millennial scale climate events in western Europe during the early last glacial period using multi-proxy speleothem records Corrick, Ellen1; Drysdale, Russell 2; Hellstrom, John2; Couchoud, Isabelle3; Wong, Henri4; Cailhol, Didier 5; Cheng, Hai6; Jaillet, Stéphane 3; Tocino, Stéphane7 1 School of Earth, Atmosphere and Environment, Monash University, Australia; 2 School of Geography, Earth and Atmospheric Sciences, The University of Melbourne, Australia; 3 Laboratoire EDYTEM, Université Savoie Mont Blanc, France; 4 Australian Nuclear Science and Technology Organisation, Australia; 5 Inrap and TRACES - UMR5608, Jean Jaurès - Toulouse University, France; 6 Institute of Global Environmental Change, Xi’an Jiaotong University, China; 7 Aven d’Orgnac, Grand site de France, France. Past abrupt climate changes act as critical analogues for understanding how the climate system may respond to future abrupt changes. One of the best examples of naturally occurring abrupt climate change is the series of millennial-scale Dansgaard-Oeschger (D-O) events that took place during the last glacial period (115,000 – 11,500 years ago). D-O events are clearly recorded in ice-cores from Greenland, with coincident climate changes detected in marine and terrestrial records spanning a range of climate zones. Greenland ice cores also record shorter-lived ‘sub-millennial’ scale events that occur within the main D-O event sequence, particularly during the early last glacial period. To what extent these sub- millennial events were expressed outside of Greenland is currently poorly understood. Here we characterise the response to sub-millennial scale climate changes in western Europe using five multi-proxy (18O, 13C, Mg and Sr) speleothem records from Saint-Marcel and Orgnac Caves, France, that collectively span 127 – 87 kyr BP. The replicated speleothem records clearly preserve both millennial D-O events and sub-millennial events, demonstrating the strong coupling between the climate of south-east France and the North Atlantic across both millennial and sub-millennial timescales. Interestingly, the multiproxy record reveals a decoupling between broad temperature (indicated by 13C) and precipitation changes (indicated by 18O) during some of these sub-millennial scale events. 37 This suggests that climate teleconnections operating during sub-millennial events were in some ways different to those during the stronger millennial-scale D-O events. 38 The Holocene hypsithermal in the Australian region Patrick De Deckker1 1 Research School of Earth Sciences, The Australian National University, Canberra Close examination of key and well-dated Holocene sites, both on land and at sea in the Australian region indicate that at the very beginning of the Holocene, the region was locked into a continuous positive Southern Annular Mode (SAM) as a result of strong westerlies. After that period , the entire region switched to a negative SAM scenario and, during that time, the westerlies must have retreated further south of Australia. Afterwards, a period of time spaning ~8,200 to ~5,500 years ago, temperatures were higher than today, including in the oceans. We refer to this as the Holocene Hyspithermal. Coincident to this period, lake levels and postulated rainfall were extraordinarily high and vegetation spectra in places very different compared to today. The extent of this period varies by a few centuries between sites, but this may result from the level of resolution and also appears to be controlled by latitude. There is also clear indication that the influence of the westerlies was reduced over Australia during those two and a half millennia. In contrast, air temperatures recognised in Antarctic ice cores are at the opposite to those recognised in Australia for the Australian hypsithermal, and atmospheric CO2 levels were at their lowest for the entire Holocene. Climatic conditions then progressively deteriorated everywhere a bit after ~6,000 years BP until recent times as ENSO signals with alternating El Niño and La Niña conditions across the entire Pacific region as already described by Perner et al. (2018) based on the same cores studied here. Brief mention is also made to the presence of humans in SE Australia during the Holocene. It seems that human activities changed well after the period of high temperatures and rainfall, with more sedentary activities along the major rivers, with an enhancement of food production in organized settings suggestive of villages. 39 A detailed study of Holocene climate variability in south-east Australia based on cellulose inferred lake water isotopes and monitoring and modelling approach at Lake Surprise, western Victoria. Dharmarathna, Asika 1; Tyler, Jonathan J. 1; Tibby, John 2; Barr, Cameron 2; Cadd, Haidee 3; Ankor, Martin J. 1; Jones, Matthew D. 4; Tadros, Carol 5; Hua, Quan 5; Child, David 5; Zawadzki, Atun 5; Hotchkis, Michael 5; Gadd, Patricia 5; Klaeb, Robert 1; Hall, Tony 1 1Department of Earth Sciences, University of Adelaide, SA 5005, Australia; 2Department of Geography, Environment and Population, University of Adelaide, SA 5005, Australia; 3School of Biological, Earth and Environmental Sciences, University of New South Wales, Australia; 4School of Geography, University of Nottingham, NG7 2RD, United Kingdom; 5Australian Nuclear Science and Technology Organisation (ANSTO), Lucas Heights, Australia During the Holocene, southeast Australia experienced intense climate conditions including extended droughts. However, knowledge of the frequency and intensity of such episodes is restricted due to the scarcity of quantitative, high-resolution climate records from the region. Where conditions are possible, oxygen isotopes preserved in lake sediments are a useful tool for retracing the past climatic and environment. Here we present a well-dated, highly resolved Holocene record based on δ18O values of aquatic cellulose, alongside organic carbon isotopes and carbon/nitrogen ratios from sediments at Lake Surprise in western Victoria. Our interpretation of the palaeo-data is supported by both monitoring of water and sediment accumulation and lake isotope mass balance modelling to track the modern hydrology of the lake. The lake is highly groundwater dependant alongside its evaporative enrichment of major ions and stable isotopes. The cellulose record indicates a trend of gradually increasing aridity towards the present day, with notable extreme wet periods prevailing from 10900 – 10000, 7600 – 7000 and 5600 – 4500 cal yr BP. the lake represent a significant climate transition to towards aridity at 4500 cal yr BP and remained consistent over the last 4000 years, along with the driest period recorded from 2000 – 1550 40 cal yr BP. while our record is consistent with other studies from western Victoria, we demonstrate a strong coherence with SWW variability suggesting that the southern Ocean processes were the dominant controls of Holocene climate change at least over the study area. Further, we suggest an increasing influence of ENSO and IOD during the last two millennia. Our record also agrees with the pattern of variation in solar forcing to some extent which may symbolize a connection to proxy data and climate drivers. However, detailed analyses focused on solar activity and climate modes are required to understand teleconnections among these climate drivers and their mechanisms. 41 Monsoonal variations in the Kimberley since human arrival – clues from new palaeoenvironmental records Dixon, Teresa1; Howie, Charmaine1; Kemp, Justine2; Rudd, Rachel1; Moss, Patrick1; McGowan, Hamish1 1 School of Earth and Environmental Sciences, University of Queensland; 2 Australian Research Centre for Human Evolution, Griffith University The wet-dry tropical climate of the Kimberley region in north-western Australia is characterised by the Indo-Australian Summer Monsoon (IASM). Variations in the strength and position of the monsoon are caused by its interaction with other regional climate drivers and have significant control on the vegetation of the region. Since the arrival of humans to Sahul, large-scale climatic changes, including Heinrich and Dansgaard–Oeshger events and the Last Glacial Maximum have influenced tropical Australasian climate phenomena. There are several intervals over the last 60,000 years, including Heinrich Stadials 5 and 1, during which the response of the IASM to these global and regional climatic events is unclear or debated, owing partly to the scarcity of records extending through this time in the Kimberley region. We present a pollen, charcoal and geochemical record extending ∼56,000 years, near to the first known arrival of humans to the continent around 60,000 years ago, collected from the southeast of the Kimberley region, on the northern edge of the Tanami Desert. The core’s location in a low-lying, seasonally inundated floodplain is consistent with regular sedimentation, capturing an environmental signal from the present-day southern edge of monsoonal influence. Preliminary results show variations in the regional environment, which indicate intervals of stronger and weaker monsoon activity. Variations in the proportion of taxa in the Amaranthaceae, Cyperaceae and Brassicaceae families alongside microcharcoal indicate changing water availability and precipitation patterns. 42 Using giant clam shell geochemistry to understand past environmental change and human-environment interaction in the South Pacific Dong, Bohao1; Prendergast, Amy L1; Drysdale, Russell1; Ulm, Sean2 1 School of Geography, Earth and Atmospheric Science, University of Melbourne, Melbourne, Australia; 2 School of Arts Society and Education, James Cook University, Cairns Climate change has been of consistent and considerable concern for the past decades and high-resolution paleoenvironmental proxies are increasingly providing critical baselines for understanding Earth’s climate system. Giant clams (Tridacnidae spp.) have a widespread distribution in the subtropical-tropical Pacific region. Compared with other archives, giant clams have advantages including high growth rate, clear increment bands and long lifespans, enabling long continuous paleoenvironmental reconstructions. The clear annual and daily shell increment bands can provide monthly, and even ultra-high daily resolution paleoenvironmental reconstruction. By analysing the geochemical composition of giant clam shells, we can faithfully reconstruct paleoclimate records, including sea surface temperature (SST), sea surface salinity (SSS), dissolved inorganic carbon (DIC), daily light cycles, rainfall, river input, marine primary productivity and extreme weather events. In this study, we apply multiple traditional and novel techniques, including Microscopy, XRF, IRMS, ICP-AES and LA-ICP-MS, to investigate giant clam shells’ growth patterns, geochemical compositions, surrounding seawater parameters and climate change in the Great Barrier Reef (GBR). Initial results show that the studied shell records 28~30 years of growth, with daily growth increments visible. The oxygen isotope-reconstructed temperature range mirrors local instrumental records, indicating that this species is a reliable paleothermometer. LA-ICP-MS trace element records show sub-annual climatic variability and extreme weather events in the GBR. We have 43 evaluated differences in proxy records between different parts of the shell and found that both inner and outer shell layers yield reliable records. This project is providing calibrated proxies for ultra-high-resolution paleoenvironmental reconstructions from the GBR, giving insight into environmental change from the last 30 yrs, and ultimately the Holocene more broadly. This provides baselines for understanding long- term social-ecological systems in the GBR and data for the future management of the reef. 44 Last Interglacial cooling in New Zealand and its potential link to a West Antarctic meltwater pulse Drysdale, Russell1; Couchoud, Isabelle2; Hellstrom, John1; Ryan, Matt3; Menviel, Laurie4; Kosarac, Nevena4; Newnham, Rewi M.5; Dunbar, Gavin D.5; Vandergoes, Marcus J.6; Hayward, Bruce7; Bostock, Helen8; Neil, Helen L.9; Lorrey, Andrew9 1 University of Melbourne, Australia; 2 Université Savoie Mont Blanc, France; 3 Pattle Delamore Partners, New Zealand; 4 University of NSW, Australia; 5 Victoria University Wellington, New Zealand; 6 GNS Science, New Zealand; 7 Geomarine Research, New Zealand; 8 University of Queensland, Australia; 9 National Institute of Water and Atmospheric Research, New Zealand The Last Interglacial (LIG) was the last time when Earth’s temperatures were warmer than present, making it an interesting target for understanding the consequences of global warming. Excess melting of polar ice sheets during the LIG produced sea levels 6 to 9 metres above present, but the source and timing of meltwater releases are debated. One way forward is to interrogate proxy records from the southern mid latitudes for evidence of a regional climate perturbation due to a high-latitude meltwater release, and test this against climate-model simulations. Here we present a precisely dated speleothem record from Nettlebed Cave (NW Nelson, New Zealand) containing an uninterrupted growth phase spanning most of the LIG (~131 - 119 ka). The chronology is anchored by 63 U-Th ages, yielding an age model with an average 95% uncertainty of 500 years. Growth-rate and carbon and oxygen isotope data reveal a millennial-scale cooling event between ~127.4 and ~124. 6 ka. The timing is consistent with a sea-surface temperature reversal preserved in nearby Tasman Sea sediments, and is broadly synchronous with cooling over Antarctica immediately following the local LIG thermal optimum. Authigenic uranium changes in sediments from the Atlantic sector of the Southern Ocean indicate reduced bottom-water oxygen at this time, and suggest a shutdown of Antarctic Bottom Water, linking Antarctic cooling to an ice-sheet meltwater pulse. 45 We ran a LOVECLIM climate-model hosing experiment to test whether collapse of the West Antarctic ice sheet (WAIS) could trigger cooling over southern New Zealand. The results reveal depressed ocean temperatures in the likely moisture-source region south of Nettlebed Cave, consistent with the Tasman Sea SST decrease and with deuterium-excess- derived SST anomalies in the source region of Antarctic precipitation. The combined evidence not only potentially constrains the timing of a complete or partial melting of the WAIS during the LIG, but also indicates a southern mid-latitude climatic response to such melting. This has implications for regional climate impacts of a future WAIS collapse. 46 Lake sedimentary ancient DNA reveals ecosystem response to fire and climate on Kangaroo Island (Karti), Australia Duxbury, Lucinda1,2 ,3; Pérez Godoy, Vilma2,3; Cadd, Haidee4,5; Tyler, Jonathan1; Francke, Alexander1; Law, W Boone6; Armbrecht, Linda3,7; 1 Department of Earth Sciences, The University of Adelaide, Adelaide, SA 5005; 2 Centre for Australian Biodiversity and Heritage, The University of Adelaide node, Adelaide, SA 5005; 3 Australian Centre for Ancient DNA, The University of Adelaide, Adelaide, SA 5005; 4 University of Wollongong, Wollongong, NSW 2500; 5 Centre for Australian Biodiversity and Heritage, University of Wollongong node; 6 Department of Biological Sciences, The University of Adelaide, SA 5005; 7 Institute for Marine and Antarctic Studies (IMAS), University of Tasmania, Hobart, TAS 7004 Increasingly hotter and drier climate combined with post-colonial changes in land management have led to more catastrophic fires across southern Australia in recent decades - threatening people and the environment. However, there is still a lot we don't understand about the complex interplay between climate, fire, ecosystems, and people - especially on longer timescales that pre-date British colonisation. Our study focuses on Kangaroo Island, where devastating bushfires decimated the island’s unique ecosystems in 2019-2020. We used shotgun metagenomics of sedimentary ancient DNA (sedaDNA) to reconstruct the aquatic and terrestrial biodiversity within the green plants group (Viridiplantae) over the last ~ 7,000 years from the sediments of Lashmars Lagoon. We compared our sedaDNA record to a pollen record, charcoal-inferred fire history and geochemical proxies for catchment and climate processes to provide new insights into plant community responses to climate and fire. We found compositional changes statistically linked to fire history and climate change. Specifically, sediment calcite content (linked to drier climates) significantly explained changes in composition within the Viridiplantae. Statistical analysis further revealed that the major compositional change within the Viridiplantae, including a decrease in the Fabaceae family (which includes the genus Acacia), coincided with an inferred increase in fire activity at ~3.3 ka. Interestingly, we also found evidence for increased amounts of plant DNA during this period of increased biomass 47 burning and or more frequent fires, alluding to the role of fuel loads and vegetation density in controlling fire regimes. Overall, our study sheds new light on the way climate and fire have shaped past biodiversity on Kangaroo Island, providing insights relevant to future fire management and further contextualising the complex human history of Kangaroo Island. Finally, this study demonstrates the potential for the preservation of sedaDNA dating back to at least ~ 7,000 years in an Australian lake and encourages the application of this novel proxy in the region. 48 Clear and Present Danger: the pure state of ignorance that has led to Australia’s bushfire crisis Fletcher, Michael-Shawn1,2 1 School of Geography, Earth and Atmospheric Sciences, The University of Melbourne, Carlton, Australia; 2Indigenous Knowledge Institute, The University of Melbourne, Parkville, Australia2 The dominant view of the causes driving many of the environmental challenges facing Australia is rooted in a misanthropic view of human-environment interactions. This view casts human activities as almost universally deleterious to the environment and posits that the antidote to our damage to the “natural” world is the removal/exclusion of humans. This view is grounded within a long history of dehumanising narratives that cast Aboriginal Australians as “intelligent parasites” who had no discernible influence on Australian environments, and thus much of Australia was in a “wilderness” state when the British invaded. Quaternary science provides the only means of empirically testing the “intelligent parasite” model, yet overly simplistic human-environment paradigms constructed from dehumanising narratives have and continue to be applied to the framing and interpretation of our data. One very real outcome of this cultural bias in science is the failure to recognise, understand and address the underlying causes of southeast Australia’s bushfire crisis. Here, I critique the deep bias inherent in palaeoecology in Australia and how this loads the dice against identifying Aboriginal agency in our data. I then synthesise more than 10 years of data arising from our laboratory that unequivocally demonstrates that culture, not climate, underpins the current bushfire crisis in southeast Australia – the removal of cultural burning unleashed an explosion of Eucalypts across southeast Australia at a scale that now threatens our very survival on this continent. Finally, I will use this data to empirically challenge the “intelligent parasite” model, highlighting the urgent need for the meaningful incorporation of alternate world views in our disciplines. 49 East Asian Monsoon dynamics in Japan as inferred from the sediments of Lake Suigetsu Francke, Alexander 1 ,2; Tyler, Jonathan 1,2; Nowinski, Vanessa 1 ,2; Tibby, John 2 ,3; Lacey, Jack H. 4; Leng, Melanie C. 4; Rex, Charlie 5; Staff, Richard A. 5; Nakagawa, Takeshi 6 1Department of Earth Science, University of Adelaide, Adelaide, Australia; 2Sprigg Geobiology Centre, The University of Adelaide, Adelaide, Australia; 3Department of Geography, Environment and Population, Faculty of Arts, Business, Law and Economics, The University of Adelaide, Adelaide, Australia; 4National Environmental Isotope Facility (NERC), British Geological Survey, Keyworth, UK; 4Scottish Universities Environmental Research Centre (SUERC), University of Glasgow, East Kilbride, UK; 5Ritsumeikan University, Shiga, Japan The climatic drivers controlling the East Asian Summer Monsoon (EASM), which directly affects water resources and water-borne geohazards for over half of the Earth’s population, are still highly debated. The long-proposed alignment between EASM and high latitude climate forcing suggested by the similarities between Greenland ice core records and speleothem archives from China is increasingly challenged by sedimentary terrestrial and marine records. But there are only a handful of palaeorecords with sufficiently accurate chronological constraints to provide insights into the lead and lag of EASM variability compared to global benchmarks, such as ice core records. The annually layered sediments of Lake Suigetsu (Japan) provide a unique opportunity to study EASM variability during periods of rapid climate change at unprecedented precision. The chronologic framework for Lake Suigetsu is an integral component of the IntCal20 radiocarbon calibration, and sampling and chronological work follows strict protocols. Lake Suigetsu’s location at the western coastline of Japan’s main island, Honshu, makes it sensitive to climatic influences by the north-westerly winter monsoon, and summer to autumn south-western and Pacific monsoonal influences. Here, we aim to use the Lake Suigetsu sediments to untangle rapid EASM variability during the last glacial cycle. Hydrologic change is reconstructed by stable isotope analysis (oxygen, carbon) of non- traditional lake sediment material, namely biogenic silica (diatoms) and early diagenetic 50 siderite (FeCO3); supported by FTIR (Fourier-Transform Infrared Spectrometry) estimates of sedimentary mineral composition. More than 1,100 samples at 1 cm resolution (siderite isotopes) and 2 cm (diatom isotopes) have been sampled at sub-millimetre precision covering rapid climate oscillations during Heinrich events 4 (around 38 kilo years ago) and 5 (around 45 kilo years ago). Analytical work is ongoing but preliminary isotope and FTIR analyses, in concert with previously collected X-ray fluorescence and pollen data, imply a delayed hydrologic response in Japan at the end of Heinrich event 4 compared to the onset of Greenland Interstadial 8. Moreover, our preliminary results display some interesting similarities between the Suigetsu proxy data and Antarctic ice core records. 51 Last Glacial pluvial periods evident in subaqueous speleothems from Australia’s southern arid-margin Gould-Whaley, Calla1; Drysdale, Russell1; May, Jan-Hendrik 1; Hellstrom, John 1; Treble, Pauline 2 ,3; Grieg, Alan 1; Cheng, Hai 4; Buswell, Clare 5 1The University of Melbourne, Australia; 2The Australian Nuclear Science and Technology Organisation, Sydney, Australia; 3The University of New South Wales, Australia; 4Institute of Global Environmental Change, Xi’an Jiaotong University, China; 5Flinders University, Australia Archives from Kati Thanda (Lake Eyre) basin indicate at least three distinct periods of lake filling during the Last Glacial Period. The headwaters of the megalake lie as far north as -19 °, therefore filling events are indicative of increased intensity of the Indo-Australian Summer Monsoon (IASM). However, due to the nature of unconsolidated materials, these archives are limited in how precisely they can constrain the timing of Last Glacial pluvial periods, and they cannot capture millennial-scale climate variability. Speleothems from Mairs Cave (Flinders Ranges, South Australia), present an opportunity to address these issues. The cave lies on the boundary between the arid and semi-arid regions and currently receives rainfall from both the Southern Hemisphere Westerly Winds (SHWW) and the IASM. The cave contains pendulites: stalactites with an external overgrowth of subaqueously precipitated calcite. The stalactites were initially submerged ~ 89 ka by rising groundwaters, which flooded the cave. From that point forward, the pendulites grew subaqueously during periods of regional groundwater recharge. Preliminary findings suggest periods of subaqueous growth align with higher Southern Hemisphere summer insolation, suggesting the site received enhanced tropical rainfall due to moisture delivery from the IASM. Growth rate and magnesium concentrations both appear to be responsive to millennial-scale climate change, exhibiting increases during both Heinrich events and the cold limbs of Dansgaard-Oeschger events. This is consistent with increased delivery of tropical moisture due to southerly incursions of the IASM. 52 The study site lies near the intersection of two ‘superhighways’ of early human expansion proposed by Crabtree et al. (2021). The cave is also 200 km directly south of the Warratyi shelter, one of the earliest sites of human occupation in southern-central Australia. Therefore, the palaeoclimate record to emerge from this research could potentially provide a more detailed climatic contextualisation for this period of human history. 53 Climate extremes recorded in playa lakes across continental Australia Grunau, Sophie1; 1 University of Wollongong; The recent flooding in Queensland and NSW has affirmed the impacts that extreme precipitation has on people’s lives and their livelihood. To be better prepared for such extremes in the future we need to know how often and under which climatic circumstances they occur. However, climate models for Australia still involve high uncertainty in predicting precipitation extremes. This is attributed to the limited paleo record of magnitude and frequency of past extremes. Though efforts have been made to improve the terrestrial record of hydro-climatic paleo data in Australia, there still exists a gap in scientific knowledge, especially on the spatial scale. Our project tackles this challenge by utilising paleoenvironmental evidence collected from various ephemeral lakes across the country. Since filling events of ephemeral lakes are strongly linked to precipitation events the terrestrial record from lakes in key quadrants of the country allows the establishment of timing, magnitude, variability, and trend of precipitation extremes in the past. A timeframe of the last thousand years permits the comparison of frequency and magnitude to inter- annual variability. While previous studies have focused on high resolution at specific locations the large spatial scale of this project enables the analysis of spatial variability and thus will result in an improved understanding of the importance of varying climatic drivers in different regions across Australia. Ultimately, by comparing the importance of climatic drivers for precipitation extremes in different regions against global climate simulations uncertainty can be reduced and future predictions of precipitation extremes can be improved. 54 Late Holocene environmental change of Te Whakaraupō | Lyttelton Harbour, New Zealand Hanson, Johanna1; Reid, Catherine1; Prebble, Matiu1; Shulmeister, James1; Moy, Chris2; Zawadzki, Atun3, Hua, Quan3 1 School of Earth and Environment, University of Canterbury, 20 Kirkwood Avenue, Upper Riccarton, Christchurch 8041, New Zealand; 2 Department of Geology, University of Otago, 362 Leith Street, North Dunedin, Dunedin 9016, New Zealand; 3 Australian Nuclear Science and Technology Organisation, New Illawarra Road, Lucas Heights, New South Wales 2234, Australia Due to the increasing impacts of climate change, global sea levels and ocean temperatures have been rapidly increasing. One region which will be affected by these increased sea levels are the bays of Horomaka | Banks Peninsula on the east coast of the South Island, New Zealand. Horomaka is a poorly understood landscape that has been highly modified by human land management in both Māori and European times. This research will investigate the interactions between changes in the coastal system and the surrounding catchments which are deeply incised valleys in the flanks of an old volcanic complex. The work focusses on three locations: Te Whakaraupō | Lyttelton Harbour, Kawatea | Okains Bay and Te Wairewa | Lake Forsyth and uses a combination of micro-fossil, geochemical and sedimentological proxies to decipher ecological, hydrological and anthropomorphic changes in these catchments. Here we present our preliminary findings from Te Whakaraupō | Lyttelton Harbour, where a 3.4 m shallow marine sediment core was collected from the mudflats of the innermost harbour. Foraminiferal records indicate a rapid infilling of the harbour with a shift in conditions from low intertidal to high intertidal to present day salt marsh. This change in sedimentation is reflected in our X-ray Fluorescence results, which show increased variability in terrigenous sediment and organic content at the top of the record. This research presents the first of its kind in Horomaka to reconstruct past environmental conditions over time. 55 Future research will include pollen and micro-charcoal analyses and grain size analysis to amplify the palaeoenvironmental data. This research will develop key information on changes in both marine and terrestrial environmental change and sedimentation rates over the late Holocene, which will help inform the management response to enhanced climate change and urban development in the harbour. 56 Synchronous onset of the last glacial termination in the southern mid-latitudes Henríquez, William1; Fletcher, Michael-Shawn1; Newnham, Rewi2; Moreno, Patricio 3; Callard, Louise 4 1School of Geography, University of Melbourne, 221 Bouverie Street, Carlton, Victoria, 3050, Australia; 2School of Geography, Environmental and Earth Sciences, Victoria University of Wellington, PO BOX 600, Wellington, New Zealand; 3Millennium Nucleus Paleoclimate, Las Palmeras 3425, Ñuñoa, 7800003 Santiago, Chile; 4School of Geography, Politics and Sociology, Newcastle University, Newcastle upon Tune, UK Detailed comparisons of Antarctic and Greenland ice core records suggest an inter- hemispheric asynchrony of climate change at the end of the last glaciation. The extent to which this climate variability, its timing and regional synchrony affected the southern mid- latitudes remains uncertain. Here we present a compilation of multiples selected terrestrial proxy paleoclimate data from key mid-latitude Southern Hemisphere landmasses spanning the last glacial-interglacial transition, focusing on the onset of the last termination (T1). Our results show that synchronous deglacial climate conditions induced terrestrial environmental shifts in Tasmania, New Zealand’s southern Island and western Patagonia at the beginning of T1, consistent with the commencement of the deglacial warming revealed by Antarctic ice records following the Last Glacial Maximum. 57 Temporal variations in the marine radiocarbon reservoir effect during the Holocene – A review Hua, Quan1 1Australian Nuclear Science and Technology Organisation, Lucas Heights, Australia This paper presents a review of spatial and temporal radiocarbon (14C) variations in the surface ocean for the Tropical and South Pacific. Radiocarbon has been recognised as a powerful transient tracer for the study of ocean circulation, and its variations associated with environmental and climatic changes. Investigation of radiocarbon changes in the surface ocean with time and space, thus, not only is crucial for accurate dating of marine samples but also delivers useful information on the carbon cycle and climatic systems. Accurate and reliable dating of marine samples (e.g., shells, corals, coralline algae and foraminifers), is increasingly critical for correlating them with terrestrial and ice-core records, and consequently for better understanding of palaeoclimate. The dating, however, is not straightforward and involves estimates of the marine radiocarbon reservoir effect (or simply the marine reservoir effect, MRE), an aging effect of the surface ocean relative to the atmosphere. Traditionally, for a given location or region the MRE is generally assumed to be constant through time and its modern, pre-1950 value is used for calibrating marine 14C ages. However, there is growing evidence that the effect is not constant but varies with time. Temporal MRE variability has been reported for a number of oceans and seas during the late Quaternary and Holocene. For the Tropical and South Pacific, large temporal changes in the MRE of several hundred to almost a thousand of years during the Holocene were documented for a number of sites across the basin. Mechanisms of these changes, and their implications for climate variability and changes in ocean circulation are discussed. 58 Willandra Lakes re-revisited: preliminary results from Lake Arumpo, NSW Jankowski, Nathan R. 1,2; Turnbull, Molly1; Parker, Adrian3; Willandra Lakes Region Aboriginal Advisory Group4 1 Centre for Archaeological Science, School of Earth, Atmospheric and Life Science, University of Wollongong, NSW, Australia; 2 ARC Centre of Excellence for Australian Biodiversity and Heritage, University of Wollongong, NSW, Australia ; 3 School of Social Sciences, Faculty of Humanities and Social Sciences, Oxford Brookes University, UK; 4 NSW National Parks & Wildlife Service, PO Box 318, Buronga, NSW, 2739 The Willandra Lakes Region is a key location for understanding both past environmental changes in south-eastern Australia and the Aboriginal heritage of the Australian continent. The landscape record here charts the interplay between fluctuating lake levels and lunette formation, while preserving the activity traces of generations of people who called this Country home. Despite ~60 years of study and the shear wealth of evidence available throughout the Willandra, the focus of geological research has remained almost entirely within the confines of the Lake Mungo basin. This study forms part on an ongoing ARC DECRA project that aims to systematically construct high-resolution chronological and stratigraphic records of landscape and vegetation change at critical locations throughout the Willandra. In this presentation, we revisit and present preliminary findings for two previously investigated locations within Lake Arumpo, downstream from Lake Mungo; Top Hut 1 (TH1) and Long Waterhole Gully (TH3). The TH1 site is located within a blow out on the Outer Arumpo lunette. Here, a succession of clean quartz sand dunes were deposited between 50 and 40 ka over the top of a basal red dune. The quartz dune is then overlain by a series of interbedded clean quartz sands and pelletal clay beds, each ~20–30 cm thick, before being capped with a well-developed palaeosol and modern mobile quartz sands. The now ~4m deep Long Waterhole Gully location was formed via catastrophic down-cutting of a drainage ditch excavated into the margin of Lake Arumpo’s floor. Here, four distinct phases of sandier sediments, representing pulses of returning water to the lake basin, are 59 interbedded with both deflated pelletal clay beds and shallow water lacustrine deposits. Preliminary optical ages indicate a punctuated sequence of deposition at Long Waterhole Gully beginning at ~46–38 ka ago and terminating sometime after ~13–9 ka ago. 60 Stability of the Antarctic Ice Sheet during the pre-industrial Holocene Jones, Richard1; Johnson, Joanne2; Lin, Yucheng3; Mackintosh, Andrew1; Sefton, Juliet1,4; Smith, James2; Thomas, Liz2; Whitehouse, Pippa 3. 1 Monash University, Australia; 2 British Antarctic Survey, UK; 3 Durham University, UK; 4 Tufts University, USA The rate and magnitude of the Antarctic Ice Sheet (AIS) contribution to global sea-level rise beyond 2100 CE remains highly uncertain. Past changes of the AIS, however, offer opportunities to understand contemporary and future ice sheet behaviour. Based on a review of evidence to date, here we outline how the AIS evolved through the pre-industrial Holocene, 11,700 years ago to 1850 CE. Three main phases of ice sheet behaviour are identified: a period of rapid ice volume loss across all sectors in the Early and Mid Holocene; a retreat inland of the present-day ice sheet margin in some sectors, followed by readvance; and continued ice volume loss in several sectors during the past few millennia, and in some areas up to and into the industrial era. Global sea levels rose by 2.4–12 m owing to the period of rapid Antarctic ice loss and possibly fell by 0.35–1.2 m owing to subsequent readvance. Changes in the AIS during the Holocene were likely driven by similar processes to those acting today and predicted for the future, which are associated with oceanic and atmospheric conditions as well as bed topography. Periods of both ice volume loss and ice volume gain would have influenced Southern Ocean circulation, with potential implications for Southern Hemisphere climate. More work is needed to better understand Antarctica’s contribution to sea-level change and role in Southern Hemisphere climate variability during the Holocene. 61 62 Reconstruction of past climate and its effects on environment, ecology, and ecosystem using long-lived bivalve shell. Kotaro, Shirai1; Kaoru, Kubota2; Naoko, Murakami-Sugihara1; Shiono, Miki1; 1 Atmosphere and Ocean Research Institute, The University of Tokyo, Japan; 2 Japan Agency for Marine-Earth Science and Technology, Japan Bivalve shells can provide a unique opportunity to reconstruct past climate and its effects on the bivalve mollusc ecology and habitat coastal environment and ecosystem. Oxygen isotopic composition of the shell is a reliable proxy for ambient temperature and salinity. Shell growth pattern provides ecological information (e.g. growth) of bivalve mollusk, which is controlled by ambient environment (e.g. temperature) and ecosystem (e.g. food source). Geochemical signatures can also provide independent information from each proxy. The Stimpson’s hard clam Melcenaria stimpsoni is a long-lived bivalve species that distributes around the north-eastern Pacific coast and is a suitable archive for such purposes. Oxygen isotope analysis of modern specimens demonstrated that the bivalve generally grew between spring to late-autumn, and maximum seawater temperature can be reconstructed. The timings of the growth cessation and re-start are likely to be affected by food availability and not solely controlled by temperature. The annual growth rate presented multi-decadal fluctuation, but its pattern was partly different from the Pacific Decadal Oscillation, likely because the dynamics of coastal productivity are slightly different from the physical oceanographic dynamics. The fossil specimens from MISs 5, 7, and 9 showed more rapid growth at the earlier ontogenetic stage, while the maximum size was smaller than the modern specimens. Reconstructed temperature suggested that the cold water Oyashio current was stronger during the MISs 5, 7 and 9, the interglacial periods. 63 Water mass history of the Southwest Pacific through the last 160,000 years using radiolarians Lowe, V.1, Cortese, G.2, Bostock, H.1 1School of Earth and Environmental Sciences, University of Queensland, Brisbane, QLD, Australia; 2Surface Geoscience, GNS Science, Lower Hutt, New Zealand It is widely accepted that the Southern Ocean plays a key role in global climate by influencing atmospheric carbon dioxide over a glacial cycle. However, questions remain regarding the changes in productivity and ocean circulation as they relate to Southern Ocean water masses. Polycystine radiolarians are a group of siliceous microplankton that inhabit the whole water column from surface to sea floor. They peak in abundance between 100 and 400 m depth and display significant diversity in the modern Southern Ocean, and their distribution is related to water masses and ocean circulation (Lawler et al., 2021; Lowe et al., 2022). Here we present a history of Southwest Pacific water mass history over the last glacial cycle using a newly developed statistical approach. We apply the Southern Ocean Water Mass Method (SOWM) and Southern Ocean Sea Ice Index (SOSI) to a transect of sediment cores through the Southwest Pacific Sector of the Southern Ocean. The cores span from the Subtropical Front to the Polar Front and represent the last glacial cycle (160,000 years). We compare the results of the SOWM and SOSI with geochemical (stable isotopes, opal content elemental variations) and other microfossil data (diatom assemblages), on the same cores. We investigate the changes in ocean circulation and water mass structure over the glacial cycle and the implications of those changes on the climate and carbon cycle. References: Lawler et al., 2021, The Southern Ocean Radiolarian (SO-RAD) dataset: a new compilation of modern radiolarian census data. Earth System Science Data 13(11): 5441-5453. Lowe et al., 2022, Ecoregionalisation of the Southern Ocean using radiolarians. Frontiers in Marine Science, 159 64 Lowe et al., In Prep, Southern Ocean Water Mass Method: A combined 3-tool statistical approach to provide new insights on the paleoceanography of the SW Pacific from radiolarian assemblages 65 Using ice core records to understand interannual- multidecadal trends in Antarctic Ice Sheet surface mass changes Macha, Jessica1; Mackintosh, Andrew1; McCormack, Felicity1; Henley, Ben2; Jones, Richard1 1 Monash University; 2 University of Wollongong; The Antarctic Ice Sheet (AIS) is currently losing mass and the causes of these changes are not fully understood. Satellite records extend 40 years, but ice sheets respond to climate from seasonal to centennial and longer timescales, meaning hundreds of years of observational data are required to understand the physical processes driving AIS surface mass balance change on interannual, decadal, multi-decadal and centennial timescales. Therefore, paleoclimate data is necessary to be able to characterise variability to differentiate between trends and variability in surface mass balance, as well as to understand the processes which drive changes in surface mass balance. This research addresses these critical gaps by characterising past variability in surface mass balance changes in Antarctic ice core accumulation records over the past 1000 years. Ice cores provide annually resolved records of accumulation changes and climate signals dating back through recent centuries. This study utilises regional composites of ice core data, which provide a helpful circum-Antarctic perspective. Regional (composite) differences as well as local (specific) ice core trends in snow accumulation are compared. Significant changes in accumulation trends are witnessed in pre-industrial and post-industrial periods, predominant frequencies of variability are identified. Distinct similarities in trends and variability in accumulation rates over the past 1000 years are witnessed across different regions of Antarctica. This study characterises present surface mass balance changes in the context of natural past variability and the anthropogenic influence on Antarctic surface mass balance changes. 66 Investigating the links between recent fire events and the accumulation and characteristics of charcoal in Temperate Highland Peat Swamps in the Blue Mountains of NSW Maisie, Maame 1,2; Mooney, Scott3; Ryan, Rebecca1,2; Zhu Xiaohong3; Thomas, Zoe3,4; Dosseto, Anthony1,2 1 Wollongong Isotope Geochronology Laboratory, School of Earth, Atmospheric and Life Sciences, University of Wollongong, Australia; 2 Organization GeoQuEST Research Centre, School of Earth, Atmospheric and Life Sciences, University of Wollongong, Australia; 3 Earth and Sustainability Research Centre, School of Biological Earth and Environmental Sciences, UNSW Sydney; 4 CHRONOS 14Carbon-Cycle Facility, UNSW Sydney; Fire is the dominant ecological disturbance and a prominent natural hazard in south- eastern Australia and its management continues to pose a number of issues. Consideration about recent trends in fire (e.g., fire becoming more extreme, more hazardous) are hampered by a relatively short instrumental and historic record. Although the accumulation of charcoal in sedimentary archives continues to be the dominant proxy of past fire, and offer much longer temporal perspectives, links between fire and charcoal are not well established globally or in Australia. Here, I will be describing my research located in several Temperate Highland Peat Swamps on Sandstone (THPSS) located in the Blue Mountains. This research primarily uses high-resolution 14C dating and charcoal analysis to consider how recent fires (intensity, area burnt, distance from the sites) are represented in the THPSS sediments (e.g., charcoal accumulation, charcoal morphology). Our aims include investigating how fire regimes have evolved over the past 100 years and to consider drivers of fire including climatic variability and historic changes in natural resource management (e.g., hazard reduction fire). Ultimately our goal is to use this calibration exercise to quantify links between charcoal characteristics and fire regime, such that this can be used to better characterize fire regimes over the many thousands of years (also preserved in sediments of these THPSS mires). 67 Linking distal dust deposits with proximal lake records within the Kati Thanda-Lake Eyre (KT-LE) Basin: Examining the environmental conditions responsible for Australian dust export and evaluating the role of aeolian processes in shaping KT-LE. Marx, Sam1; Cohen, Tim2,1; May, Jan-Hendrik3,1; McGowan, Hamish4; Kamber, Balz5; Petherick, Lynda6 1GeoQuEST Research Centre, School of Earth, Atmosphere and Life Sciences, The University of Wollongong, Australia; 2ARC Centre of Excellence for Australian Biodiversity and Heritage, University of Wollongong, Australia; 3School of Geography, Earth and Atmospheric Sciences, University of Melbourne, Australia; 4School of Earth and Environmental Sciences, The University of Queensland, Australia; 5School of Earth and Atmospheric Sciences, Queensland University of Technology, Australia; 6School of Geography, Environment and Earth Sciences, Victoria University of Wellington, New Zealand. The lower Kati Thanda-Lake Eyre (KT-LE) Basin, including Kati Thanda-Lake Eyre (KT-LE) itself, is Australia’s biggest dust source today and likely has been throughout the late Quaternary. Distal dust records from the Australian seaboard and marine basins indicate high variability in continental dust emissions, implying changing conditions in dust source areas (or changing source areas). Contemporary studies point to hydro-climate variability being the most significant control on dust activity. At KT-LE, palaeo-shoreline records indicate pronounced hydrological variability over the past glacial cycle, which could account for variability in dust emissions. This includes a generalised reduction in lake levels during the last 100 ka, particularly after 48 ka. Recent detailed revaluation of the iconic Williams Point sequence at KT-LE confirms this general pattern, but also indicates variability within this generalised drying trend. Previous work at Williams Point suggested a number of net dust deflation episodes, hypothesised to have resulted in lake-bed lowering. In this study we re- 68 examine the links between continental-scale dust emissions reconstructed along Australia’s seaboard/marine basins and palaeo-environmental conditions at KT-LE. Results show long- term dust emissions are well linked to hydrological conditions at KT-LE throughout the last two glacial cycles. However, they imply that the formation of the substantive proximal Williams Point aeolian unit has little association within continental scale dust emissions, implying aeolian activity is not a uniform process across KT-LE. There is also little evidence of significant net-dust deflation events recorded downwind of KT-LE, with the exception of a dust pulse during the Last Glacial Maximum. In summary, we still have much to learn about dust emission processes at KT-LE. 69 A multi-proxy record of environmental change at a glacial Nothofagus refugium, Wyelangta, Victoria Matley, K A1; Drinnan, A N1; Sniderman, J M K2; Hua, Q3 &Porch, N4 1 University of Melbourne School of Biosciences; 2 University of Melbourne School of Geography, Earth and Atmospheric Sciences; 3 Australian Nuclear Science and Technology Organisation; 4 Deakin University School of Life and Environmental Sciences Despite its widespread use in palaeoecology, pollen-based reconstructions are limited by coarse taxonomic resolution. Pollen of narrow-range species that might be used as ecological indicators, for example, can be difficult or impossible to distinguish from the pollen of geographically widespread, and therefore less informative, taxa. Plant macrofossils, by contrast, are routinely identified to species level, and a majority of the species present in Southeast Australia during the late Quaternary still exist today. These improvements to the taxonomic precision of palaeobotanical records allow for the use of bioclimatic niche models to quantitatively reconstruct palaeoclimate, based on fossil species’ modern day climatic niches. Combining these two proxies, we are able to produce a more nuanced interpretation of late-Quaternary vegetation and climate. We sampled for pollen and plant macrofossils at a known late Quaternary palynological site in the Otways, Victoria (McKenzie & Kershaw, 2000). Here, we present a detailed pollen record and use plant macrofossil remains to confirm species identifications and conduct bioclimatic niche modelling. Our study reveals that, although the site has remained a rare mainland refugium for Nothofagus cunninghamii throughout the entire period of the record, the regional vegetation has undergone significant environmental change. By employing a multi-proxy approach that encompasses both pollen and macrofossil analysis, this study provides precise new estimates of the composition of Southeast Australian biotic communities and climates. These results contribute to the globally significant debate around the influence of the late Quaternary climate over the generation 70 and maintenance of terrestrial biodiversity, and to t