Paleoenvironmental history preserved in shoreline dunes of the Wimmera lake overflow system, Wotjobaluk Country, south-eastern Australia

Australia’s dryland margins are increasingly vulnerable to drought, flood and fire. Investigating past landscape and climate conditions using evidence preserved within landforms and their sediments provides important context for past, present and future climate-coupled water availability and landscape change. Such work is challenging in the Australian context, however, due to the sparse preservation of paleoenvironmental records and high spatial heterogeneity. Our study focuses on the Wimmera catchment, located on the dryland margins of south-eastern Australia, which is an understudied region of high agricultural, ecological and cultural importance. The landscapes of the Wimmera comprise a unique overflow-lake system with well-preserved shoreline dunes. Shoreline dunes form valuable archives of past hydrologic lake conditions in this semi-arid region; deflation of the lake floor, and transport of these sediments onto the dunes, records preservation of the adjacent lake’s condition within the sediments. We combine optically stimulated luminescence (OSL) dating of single grain quartz to derive depositional ages, and a larger chronological dataset using portable OSL measurements, with facies characterisation from field observations and grainsize measurements, to provide first insights into the rich history preserved within these lake shoreline dunes.