Patricia Fanning

Exposure ages from mountain dipsticks in Mac. Robertson Land, East Antarctica, indicate little change in ice-sheet thickness since the Last Glacial Maximum

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.

AN ASSESSMENT AND ARCHAEOLOGICAL APPLICATION OF CORTEX MEASUREMENT IN LITHIC ASSEMBLAGES

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 methods 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.

A geomorphic framework for understanding the surface archaeological record in arid environments

We present data from Australian study areas that support episodic nonequilibrium as a suitable model for developing a theoretical and methodological framework for interpreting the surface archaeological record. According to this model, long periods of little or no geomorphic activity are punctuated by catastrophic events that erode or deposit sediments, and hence remove or cover up surface stone artefact deposits discarded by Indigenous people in the past. We demonstrate the impact of a single rainfall event on the surface archaeological record at one of our western New South Wales study locations. We then use the results of Optically Stimulated Luminescence (OSL) of sediments underlying the artefact deposits and radiocarbon dating of associated heat-retainer hearths to suggest that both landscape chronology and the surface archaeological record are reflections of a series of episodic events such as this rain event. We conclude that, at least in our study area, the archaeological record is discontinuous in time because geomorphic events have removed the record equating to particular time periods. This process is cumulative so that the record of recent times is much more common when compared to that from earlier times. The episodic nature of geomorphic processes also has an effect on human behaviour, such that occupation of place is discontinuous. The methods by which the archaeological record is surveyed and interpreted need to take into account these spatial and temporal landscape discontinuities.

Artifact Visibility at Open Sites in Western New South Wales, Australia

Abstract Surface visibility is a significant constraint in archaeological survey, and estimates of surface visibility are a common addition to cultural resource management reports. Despite this, relatively few studies have attempted to identify the factors affecting visibility and quantify their effects. We report the results of such a study based on analysis of surface stone artifacts deposited by prehistoric hunter-gatherers from the Stud Creek area in what is now Sturt National Park, western New South Wales, Australia. While we are able to demonstrate and quantify relationships between high artifact visibility and erosional surfaces, and low visibility and vegetated or depositional surfaces, our findings also indicate a high degree of local variability. This variability sometimes obscures the predicted relationships. The outcome of this research leads us to question the way some sampling designs for archaeological survey are constructed.

Modelling the palimpsest : an exploratory agent-based model of surface archaeological deposit formation in a fluvial arid Australian landscape

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.

Assemblage formation as a result of raw material acquisition in Western New South Wales, Australia

Abstract Quarries are often defined as locations where people in the post gained access to raw material. Here we consider the definition of quarries in a raw material-rich environment. Stone artifacts found adjacent to two silcrete outcrops that might be labeled as “quarries” are compared with those found at a creek-side “occupation “location in western New South Wales, Australia. We investigate these attributions by considering the technology of raw material procurement in relation to the chronology implied by the age of the surfaces on which the artifacts rest. We assess assemblage patterning in relation to the time period over which assemblages were deposited at each of the locations. Time provides a more useful means than function for understanding differences in assemblage composition.

Burkes Cave and Flaked Stone Assemblage Variability in Western New South Wales, Australia

Abstract In 1970, Harry Allen excavated a small section of creek terrace adjacent to Burkes Cave in the Scope Range of western New South Wales, revealing a stratified deposit dated by a single radiocarbon determination to c.2000 BP. An analysis of the stone artefact assemblage was never fully published. In this paper we present a description of the technological characteristics and composition of the stone artefact assemblage from this important site and consider similarities to and differences from other western New South Wales assemblages we have studied.

Geoarchaeology in Australia: Understanding Human-Environment Interactions

Abstract This paper reviews the long history of interaction between scientists working in geomorphology, stratigraphy, sedimentology and chronology and those working in archaeology to understand past human–environment interactions in Australia. Despite this close collaboration, differentiating environmental impacts from the influence of human behaviour has proven difficult in research on key topics such as the causes of megafauna extinction, the significance of fire, and the impact of climatic shifts such as the El Niño–Southern Oscillation. Geoarchaeological research focused on depositional environments and post-depositional change in western New South Wales, Australia, provides important examples of how processes acting over different temporal scales affect archaeological deposits. The archaeological record is in some places discontinuous in time because geomorphological activity has removed the record of particular time periods, and it is discontinuous in space because it is preserved only in places that are geomorphologically relatively inactive. Important inferences concerning past human behaviours may be drawn from the record, but the processes responsible for both the presence and absence of the record must be considered. More attention needs to be given to ensuring that datasets with a similar temporal resolution are compared if the causes for behavioural changes in the past are to be correctly understood.

Footprints in the sand : appraising the archaeology of the Willandra Lakes, western New South Wales, Australia

Here is a paper of pivotal importance to all prehistorians attempting to reconstruct societies from assemblages of shells or stone artefacts in dispersed sites deposited over tens of thousands of years. The authors demonstrate the perilous connections between the distribution and content of sites, their geomorphic formation process and the models used to analyse them. In particular they warn against extrapolating the enticing evidence from Pleistocene Willandra into behavioural patterns by drawing on the models presented by nineteenth-century anthropologists. They propose new strategies at once more revealing and more ethical.

Aboriginal Use of Fire in a Landscape Context: Investigating Presence and Absence of Heat-Retainer Hearths in Western New South Wales, Australia

A case study from western New South Wales, Australia, illustrates the age, preservation, and distribution of late Holocene heat-retainer hearths that are abundant in the semiarid archaeological record in the region. These hearths were constructed as underground ovens with stone heat retainers. They appear archaeologically as eroded concentrations of heat-fractured stone sometimes protecting charcoal deposits. We explore geomorphic processes influencing hearth temporal and spatial distributions using a neutral agent-based model. Parallels between model outcomes and the distribution of hearths in space and time suggest that processes of sediment erosion and deposition are having complex effects on hearth survivorship and therefore on patterns of hearth frequency. We consider the various processes that explain why hearths were made in the past and how they manifest in the present. Despite the relatively recent age of the hearths when compared with evidence for fire use in the Paleolithic record, the presence and absence of these fire features reflect the outcome of a large number of processes interacting together, not all of them related to human behavior. We use the results of the case study to comment on current behavioral models for the presence and absence of fire use in the distant past.