Past changes in East Antarctic Ice Sheet (EAIS) volume are poorly known and diffi cult to measure, yet are critical for predicting the response of the ice sheet to modern climate change. In particular, it is important to identify the sources of sea-level rise since the Last Glacial Maximum (LGM), and ascertain the present-day stability of the world's largest ice sheet. We present altitudinal transects of 10 Be and 26 Al exposure ages across the Framnes Mountains in Mac. Robertson Land that allow the magnitude and timing of EAIS retreat to be quantifi ed. Our data show that the coastal EAIS thinned by at most 350 m in this region during the past 13 k.y. This reduction in ice-sheet volume occurred over a ~5 k.y. period, and the present icesheet profi le was attained ca. 7 ka, in contrast to the West Antarctic Ice Sheet, which continues to retreat today. Combined with regional offshore and terrestrial geologic evidence, our data suggest that the reduction in EAIS volume since the LGM was smaller than that indicated by contemporary ice-sheet models and added little meltwater to the global oceans. Stability of the ice margin since the middle Holocene provides support for the hypothesis that EAIS volume changes are controlled by growth and decay of Northern Hemisphere ice sheets and associated global sea-level changes.

We describe an experimental test and archaeological application of the solid geometry method for the interpretation of cortical surface area in lithic assemblages proposed by Dibble et al. (2005). Experimental results support the method's accuracy while archaeological application to assemblages from western New South Wales, Australia suggests a repeated pattern of the selective removal of artifacts away from their location of manufacture. These findings shed light on the role curation and mobility play in the use and eventual discard of those artifact classes for which conventional measures of curation are not applicable. The results raise new questions about Aboriginal technological organization and land use, while simultaneously highlighting the complex relationship between past human behavior and archaeological assemblage content.

Archaeologists make inferences about past human behaviour based on patterned material residues in various depositional contexts, including existing landsurfaces. These deposits are generated by processes that may obscure patterns at some observational scales while highlighting others, and interpretive differences can arise from a lack of explicit models of deposit formation. Here, an exploratory agent-based model based on the concept of the palimpsest is used to examine the effects of episodic sediment transport on the visibility and preservation of surface archaeological deposits in a fluvial context. Outcomes from the model indicate that the compound influences of preservation and visibility are capable of transforming a static radiocarbon record into one of increasing intensity towards the present, while simultaneously displaying periodic chronological gaps – features that have been used in our Australian study area to argue for demographic change driven by social or environmental factors. To differentiate between interpretations, expectations derived from the model are assessed against a second proxy from the same study area: Optically Stimulated Luminescence dates from hearth stones in surface contexts. Results indicate that patterns in the chronometric proxies from the study area are more consistent with episodic geomorphic change than explanations invoking changes in the local organization of human activity.

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SH, GC, TO, SG, JR:

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An analysis of surface scatters of stone artifacts from late Holocene contexts at Stud Creek, Sturt National Park in the northwest of New South Wales, Australia, is reported. A sedimentological and archaeological chronology for Stud Creek shows archaeological remains are no older than 2000 years and Stud Creek saw repeated occupation during the last two millennia. Methods are proposed whereby conflated stone artifact assemblages from different locations within the Stud Creek catchment can be analyzed to understand how use of the catchment differed from place to place. We propose "place use history," as a more useful concept than "settlement system" for understanding surface artifact assemblages.