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Archaeological deposits from Boodie Cave on Barrow Island, northwest Australia, reveal some of the oldest evidence for Aboriginal occupation of Australia, as well as illustrating the early use of marine resources by modern peoples outside of Africa. Barrow Island is a large (202 km2) limestone continental island located on the North-West Shelf of Australia, optimally located to sample past use of both the Pleistocene coastline and extensive arid coastal plains. An interdisciplinary team forming the Barrow Island Archaeology Project (BIAP) has addressed questions focusing on the antiquity of occupation of coastal deserts by hunter-gatherers; the use and distribution of marine resources from the coast to the interior; and the productivity of the marine zone with changing sea levels. Boodie Cave is the largest of 20 stratified deposits identified on Barrow Island with 20 m3 of cultural deposits excavated between 2013 and 2015. In this first major synthesis we focus on the dating and sedimentology of Boodie Cave to establish the framework for ongoing analysis of cultural materials. We present new data on these cultural assemblages – including charcoal, faunal remains and lithics – integrated with micromorphology, sedimentary history and dating by four independent laboratories. First occupation occurs between 51.1 and 46.2 ka, overlapping with the earliest dates for occupation of Australia. Marine resources are incorporated into dietary assemblages by 42.5 ka and continue to be transported to the cave through all periods of occupation, despite fluctuating sea levels and dramatic extensions of the coastal plain. The changing quantities of marine fauna through time reflect the varying distance of the cave from the contemporaneous shoreline. The dietary breadth of both arid zone terrestrial fauna and marine species increases after the Last Glacial Maximum and significantly so by the mid-Holocene. The cave is abandoned by 6.8 ka when the island becomes increasingly distant f

A whole emu egg, with infilling sediment believed to be coeval with egg laying and burial, was found in late Pleistocene lunette sediments near Lake Eyre, central Australia. The stratigraphic context and initial amino acid racemization (AAR) results suggested an age between 25 ka and 35 ka, ideal for a multiple cross-dating comparison. The sediment infilling the egg provided material for luminescence dating that minimized problems of association. Age estimations from AAR, 14C and U series methods were obtained from the eggshell and optically stimulated luminescence (OSL) of the infilling sediment. All methods agreed within their respective dating uncertainties confirming the utility of all four methods. They indicate an age for the emu egg of 31.24 ± 0.34 ka.

Our reconstructed history of Lake Eyre provides the first continuous continental proxy record of Australian monsoon intensity over the past 150 k.y. This continental record's broad correspondence to the marine isotope record demonstrates that this very large catchment, with its hydrology dependent on a planetary-scale climate element, responds to Milankovitch-scale climate forcing. Abrupt transitions from dry phases to wet phases (ca. 125 and 12 ka) coincide with Northern Hemisphere winter insolation minima rather than Southern Hemisphere summer insolation maxima, indicating that Northern Hemisphere insolation exerts a dominant control over the intensity of the Australian monsoon. Stratigraphic and dating uncertainties of other wet phases preclude conclusive correlation to specific insolation signals but, within the uncertainties, are consistent with Northern Hemisphere forcing. Regardless of the hemispheric forcing, the low intensity of the early Holocene Australian monsoon-by comparison with the last interglacial and particularly the last high-level lacustrine event at 65-60 ka when all forcing elements were modest-is an enigma that can be explained by a change in boundary conditions within Australia.

Lake Lewis is the furthest from the coast of Australia's salt lakes and lies at the southern edge of influence of the Australian monsoon regime. The MacDonnell Ranges south of the lake intercept moist air masses crossing the region and efficiently deliver water and sediment to the lake and its surrounding alluvial plain. We describe lacustrine, fluvial and aeolian environments of the basin and report optically stimulated luminescence (OSL) dates from representative sediments. A long period of generally wetter conditions during most of the Pleistocene is represented by thick uniform lacustrine clay beneath and near Lake Lewis. This is overlain by more heterogeneous lacustrine sediments deposited since hydrologic closure of the basin, which indicate fluctuating climatic conditions. OSL results show that dune building in the basin commenced before 95 ka, when salinity at the depocentre was high. Dune building peaked around 23-21 ka. OSL ages of fluvial deposits show that floods occurred during the last 20 ka, following the last phase of maximum aridity in the region.

Optical dating of river terrace sediments has been carried out in a test of the methodology for luminescence age determination of river terrace formation over the last 100 ka. In this study, samples were collected at river terraces, whose ages were estimated by marker tephra geochronology and from a recent riverbed in the Kanto Plain, Japan. Samples from the recent riverbed show a weak OSL signal only and gave young ages. Samples of river terrace sediments for optical dating were collected systematically from the section of about 8 m at the wall of a gravel quarry. The optical ages found corresponded well with those estimated by the age of the marker tephras for samples deeper than 2.5 m. However, the samples from the ground surface to 2.5 m exhibited considerable scatter in the growth curves and gave a wide range of ages, all significantly exceeding expectation. This was attributed to the mixing of different age sediments by inundation and/or human activities. Analyses of OSL from single grains of quartz confirmed that these sediments were composed of grains having a wide range of palaeodoses, consistent with such mixing.