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The design, simulation, manufacture and measurement of a W-band five-fold (5F) helically corrugated waveguide (HCW) is reported. The 5F HCW is based on the coupling of the traveling TE31 and near cut-off TE22 modes to create an operating eigenwave. The fabricated test structure has circular waveguide ports and features elliptical polariser sections and broadband TE11 to TE31 mode converters on either side of the 5F HCW. The optimised mode converter design, based on a four-fold (4F) HCW, has a predicted power conversion efficiency greater than 90% from 89 to 102.5 GHz, and 96% peak efficiency at 94 GHz. The optimization of the 5F HCW geometry produced an eigenwave suitable for gyro-devices, but the optimization could equally well have been directed to applications such as pulse compression and microwave undulators. Analysis of simulated electric field profiles showed that the propagating power in the 5F HCW was increased by a factor of 6 over that in the 3F HCW at equivalent peak electric field strength. This is due to the larger diameter of the waveguide. Test structures were manufactured through a combination of precision machining of a sacrificial mandrel, copper growth by electroforming followed by removal of the aluminium mandrel by chemically etching. Measurements of the 5F HCW structure’s dispersion showed excellent agreement with the prediction over the design range of 90 to 98 GHz.

Unresolved questions about the nature and coherence of microlithic production in Sri Lanka underlay many discussions about the microlith tradition in this region as well as the origins of those technologies and norms. Previous studies have not examined whether there were changes over time in the form of the microliths themselves, and in this paper, we conduct a geometric morphometric (GM) assessment of the shape differences over time at the Batadomba-lena site in the Wet Zone of Sri Lanka, excavated by Deraniyagala and Perera. We show that there were complex shifts in microlith shapes, with diversification of forms over time. This finding challenges conventional typological depictions of sameness within microliths and introduces a new approach to studying the evolution of microlith form.

International audience; HARMONI is the first light, adaptive optics assisted, integral field spectrograph for the European Southern Observatory’s Extremely Large Telescope (ELT). A work-horse instrument, it provides the ELT’s diffraction limited spectroscopic capability across the near-infrared wavelength range. HARMONI will exploit the ELT’s unique combination of exquisite spatial resolution and enormous collecting area, enabling transformational science. The design of the instrument is being finalized, and the plans for assembly, integration and testing are being detailed. We present an overview of the instrument’s capabilities from a user perspective, and provide a summary of the instrument’s design. We also include recent changes to the project, both technical and programmatic, that have resulted from red-flag actions. Finally, we outline some of the simulated HARMONI observations currently being analyzed.

This article re-envisages the human settlement of Australia’s deserts. It makes a case for their early occupation at the continental scale (a) by c. 60 ka; (b) during an early wet phase; (c) with rapid expansion of people; (d) relying on water features; and (e) showing changes through time in response to changing regional conditions. It is now well established that Australia’s deserts are as diverse as they are extensive and that ‘behavioural dynamism’ provides a better explanatory framework for arid zone social organization than ‘cultural conservatism’. Conceptual building blocks to explain desert settlement have included the process of human biogeography, the role of cryptic refugia in providing wide-scale foraging networks, and shifts in mobility in response to the Last Glacial Maximum (LGM) and other climatic events. The models which have emphasized different characteristics and scales of change in desert societies include peoples’ responses to ‘glacial refugia’, ‘desert transformations’, ‘water distribution’, and ‘cryptic refugia’. The article synthesizes new archaeological results and climate data from key sites across Australia’s deserts. The authors propose a new model for the settlement of Australia’s arid zone based on new climatic and archaeological data and finer-grained ecological and social approaches.

Modern satellite imaging offers radical new insights of the challenges and opportunities confronting traditional Aboriginal ecology and land use in Australia’s Western Desert. We model the likely dynamics of historic and precontact desert land use using Earth observation data to identify the distribution of suitable foraging habitats. Suitability was modelled for an ideal environmental scenario, based on satellite observations of maximal water abundance, vegetation greenness, and terrain ruggedness. Our model shows that the highest-ranked foraging habitats do not align with land systems or bioregions that have been used in previous reconstructions of Australian prehistory. We identify impoverished desert areas where unsuitable foraging conditions have likely persisted since early in the last glacial cycle, and in which occupation would always have been rare. These findings lead us to reconsider past patterns of land use and the predicted archaeological signature of earlier desert peoples.

Signalling is a critical capacity in modern human cultures but it has often been difficult to identify and understand on lithic artefacts from pre-literate contexts. Often archaeologists have minimized the signalling role of lithic tools by arguing for strong form-function relationships that constrained signalling or else imposed ethnographic information on the archaeological patterns with the assumption they assist in defining the signalling carried out in prehistory. In this paper I present a case study for which it can be shown that function does not correlate with form and that the technology fell out of use 1000–1500 years ago. This means that neither presumptions of continuity in social practice nor reference to tool use provide strong explanations for the size, shape standardization and regional differentiation of Australian microliths. Sender-receiver signalling theory is harnessed to motivate a new synthesis of these microliths, and I demonstrate that not only were these artefacts probably key objects used in public signalling but also that sender-receiver frameworks enable us to infer details about the operation of the signalling system.

HyMap™ airborne hyperspectral imagery was used to discriminate and map hydrated silica mineralization in the Dalhousie Springs area of central Australia. A spectral feature fitting algorithm was used to match laboratory reference spectra with image pixel spectra, producing a scaled goodness-of-fit raster map of silicified “tool-stone” sources in our study area. Subsequent fieldwork indicated that the algorithm mapped silcrete, a rock composed of hydrated silica, and incidentally, the most frequently utilized raw material for stone artifact manufacture in this area of the Australian arid zone. The soundness of our hydrated silica mineralization map is supported with field observations and spectroscopic analysis of collected silcrete samples. Independent siliceous rock mapping produced by the Commonwealth Scientific and Industry Research Organization offers additional corroboration of our results. Based on the success of our approach, we suggest that archaeologists working in Australia and in similar arid environments elsewhere have much to benefit in using advanced remote sensing products to map lithic resources, including time and cost-saving advantages for field logistics, enriched assessments of land suitability for archaeological site types, and an improved understanding of resource distributions.

Religious stories of Australian Aboriginal people, myths, were not stable and long lasting; they were often short-lived and frequently changed. High rates of turnover in narrative content allowed t...

A previous use-wear and residue analysis of backed artefacts from Deep Creek Shelter showed that they had a range of functions and hadbeen used with a variety of raw materials. Were non-backed retouched flakes at Deep Creek used for different purposes? To answer thisquestion, 40 non-backed specimens were selected for microscopic use-wear and residue analysis. Not all of these non-backed artefacts hadbeen used, but we identified that many were scrapers, knives, incisors and saws. These tools were used for bone-working and wood-working,and possibly skin-working and non-woody plant-processing. Some of these non-backed retouched artefacts were hafted. For the first time,these results allow comparison of the tool use of backed and non-backed artefacts in Australia. At Deep Creek, the range of functions forthe non-backed component was extremely similar to that of the backed artefacts. Although both artefact categories displayed similar tooluse, they are distinguished in one interesting way: non-backed specimens were often single purpose, dedicated to one function, whereasbacked artefacts were often multifunctional and multipurpose. These results help us understand the structure of tool use in Australia

We document long-term evolution in the rate of heat treatment in Eastern Australia and explore them as a technological response to dynamic industrial and social contexts that developed in the last 25 millennia. We employed methods previously used in Africa but novel in Australia to infer long-term directional changes in the relative frequency of silcrete artefacts that were heat-treated. Our methods involved independent and cross-verifying tests of the presence or absence of heat treatment, employing visual classifications and surface roughness measures. These methods revealed a coherent series of increases over time in the landscapes around Sydney, so that Late Holocene assemblages displayed higher rates of heat treatment than terminal Pleistocene or Early Holocene ones. We hypothesise that the directional trend towards greater frequencies of heat-treated artefacts on Australia’s eastern seaboard is explicable in terms of the context of technological shifts towards microlith production superimposed onto an even longer term process of lithic resource depletion, perhaps compounded with the development of political barriers to the redistribution of knappable stone.

The Still Bay is a key technocomplex within the Middle Stone Age (MSA), and Sibudu, in Kwa-Zulu Natal, South Africa, provides one of the longest and richest pre-Still Bay to Still Bay sequences. It has been hypothesised that the Still Bay industry emerged through technological revolution or alternatively through gradual change. In this paper we conduct a geometric morphometric (GM) assessment of the shape differences between the pre-Still Bay and Still Bay points at Sibudu to assess their implication for technological evolution. Pre-Still Bay points are often thought of as unifacial and single-pointed, and Still Bay points as bifacial and double-pointed. Our analysis reveals a more complex and evolving pattern, lending support for the gradual change hypothesis. When the earliest pre-Still Bay points are compared with the Still Bay points, a significant difference in shape is seen. However, intermediate units provide evidence of an evolutionary continuum between those distinct ends of the continuum.

Ground-edge artefacts (GEAs), also known as ground-edge axes, are an independent innovation that date to the earliest sites in Sahul (the continental landmass of Australia and New Guinea). During the Pleistocene, these tools were localized to the northern parts of the continent. Over time, significant changes took place in the distribution of GEAs, which became an almost continent-wide technology, with distinct regional variations in their form, production, and exchange patterns. This article explores the evolution of GEAs in Sahul, mapping the different trajectories in their production, use, and exchange, while also exploring the different roles that they may have played both socially and economically in their communities of use.

Heat treatment of stone for tool making has important implications for our understanding of the early human history of the Australian continent. New data on the antiquity of Australian heat treatment and its evolution through time in different regions have posed questions about the origin and temporal stability of technical practices. In this paper, we present the first evolutionary sequence of the use of heat treatment in Central Australia, with a trend to lower levels of heat treatment over time. Different trends are found in other regions across Australia: on the eastern seaboard, heat treatment became more prevalent over time, while in the inland, semi-arid Willandra lakes region heat treatment gradually disappeared over time. In central Australia, the long-term trend is towards fewer heat-affected specimens over time, but this happens in a single transition from stable high levels in the Pleistocene to stable moderate levels in the Mid- to Late Holocene. These evolutionary trends are consistent with regional diversification, reflecting adaptations to local conditions, and are not consistent with technological uniformity across the continent.

Landscapes throughout any region vary in the resources they contain. We investigate how Holocene forager populations adapted to this variation in a linear sand dune desert of arid South Australia. We use data from surface scatters of stone artefacts collected during pedestrian survey to compare behaviours at landform boundaries to behaviours at the centers of landforms. We propose a model of human use of the landscape that predicts the prehistoric occupants of the study were sensitive to the different economic potential of subtly dissimilar landscapes. In evaluating the model we find that there are different densities of archaeological sites in each landscape type. We also find indications of a boundary effect resulting from people having used marginal areas of each landscape type in response to the resource characteristics of adjoining landforms. In addition, we make some observations on our field data collection methods, identifying the general conditions where mobile GIS may be optimally efficient for archaeological survey.

Archaeological evidence of technology reflects myriad influences on past life, including economic contexts and mobility, which remain at the forefront of archaeological science. Given that forager groups needed to anticipate future technological needs and often had to transport tools, provisioning was necessary to enhance foraging success. Scheduling of production ensures suitable tools were available, maintained, and transported to where they were needed. This study investigates these fundamentals of interpreting past technological organisation via a critical examination of transport utility measures detected amongst bifacial points of late Holocene Australia. By focussing on one widely adopted model of these utility measures, we offer a new perspective on quantifying tool provisioning and interpreting forager mobility. These bifacial points were systematically geared to produce small and light specimens with low utility. Thus, foragers employed a strategy that sacrificed the benefits of extended utility in risky economic contexts. In return, they benefitted from having small points capable of being hafted to composite tools, enhanced the performance of those composite tools, and were light enough to permit multiple composite tools to be carried across the mid to late Holocene landscape of north Western Australia.

This review focuses on the relationships between palaeoenvironmental change and prehistoric occupation in the driest part of the Australian arid zone. Palaeoclimatic evidence from the last ∼60 ka identified fluctuating periods of wet and dry conditions during the late Pleistocene and Holocene. For most of this period conditions were arid, including during the Holocene, and maximum aridity occurred at the LGM which peaked at ∼21 ka. Maximum wetness occurred before ∼45 ka, at ∼33–31 ka and episodically during the deglaciation between ∼18 and 11 ka. The pre-LGM archaeological record is extremely sparse but records from the LGM through to the mid Holocene show people occupied the dunefields and stony plains during prolonged wet periods in the deglaciation and largely abandoned them during drier phases, retreating to better-watered refuges. Human occupation in dunefields from the LGM through to the mid Holocene can be used as a proxy for past climates. From the late Holocene changes in settlement patterns were made possible by the social, economic and technological adaptations which allowed people to occupy what became an increasingly harsh environment. These reconstructions were facilitated by discoveries in the Roxby dunefield of buried stratified layers of stone artefacts in dune sands, dated by single–grain luminescence analyses. These discoveries indicate the possibility that hitherto unreported cultural sequences, potentially dating back to >50 ka, may be present in many Australian dunefields.

We report evidence for the world’s earliest ground-edge axe, 44–49,000 years old. Its antiquity coincides with or immediately follows the arrival of humans on the Australian landmass. Ground/polished axes are not associated with the eastward dispersal of Homo sapiens across Eurasia and the discovery of axes in Australia at the point of colonisation exemplifies a diversification of technological practices that occurred as modern humans dispersed from Africa. Ground-edge axes are now known from two different colonised lands at the time humans arrived and hence we argue that these technological strategies are associated with the adaptation of economies and social practices to new environmental contexts.

Archaeological excavations at Ingaanjalwurr rockshelter in western Arnhem Land, Northern Territory, have revealed evidence of human settlement on the East Alligator River floodplain from approximately 1900 years ago through to the twentieth-century. This short report summarises the results of archaeological excavations at the site, focusing on dated distributions of stone artefacts as the primary retrieved cultural material. The excavations revealed two main periods of occupation: the earlier from c. 1900 to 1300 cal. BP and the latter from c. 460-300 cal. BP to the proto-historic period. The findings from Ingaanjalwurr broadly correspond to previously proposed regional settlement trends, whereby Aboriginal settlement shifted to newly stabilised freshwater environments during the later Holocene period.

This singular book represents a new kind of synthesis about Australian desert prehistory. We have seen some marvellous volumes that published the results of higher degree research, such as those by...

The evolution of heat treatment for stone artefact production is a subject of major interest for our understanding of early modern humans. In this study, we examine the evidence from one region in Australia to provide a new record of the antiquity of heat treatment, explore chronological shifts in the frequency of heat treatment, and discuss the implications of these findings for early population dynamics and the technical knowledge early settlers might have brought with them. Until now, Australian heat treatment has only dated back 25000 years. This study of the Willandra Lakes, including Lake Mungo, has identified the oldest systematic evidence of heat treatment yet reported in Australia, dating to ∼42000 years. We also document time-dependent directional change in the frequency of the practice. At those early times, with over 60% of all silcrete artefacts heat-treated, we hypothesize that the practice was mastered and integrated as a recurrent technical solution to the complexities of knapping silcrete. Over time, the use of heat treatment decreased progressively until less than 10% of the artefacts were heat-treated in the terminal Holocene. This trajectory has implications for understanding the antiquity of heat treatment on the Australian continent and for investigating the factors that governed its use.

Bipolar techniques enable knappers to (i) fracture very small lithic cores, (ii) reduce cores to a smaller size than is convenient and efficient with freehand knapping techniques, and (iii) to remove relatively large flakes from those small cores. In this paper the capacity of bipolar percussion knapping to extend reduction is explored with a model relating the level of engineering difficulty to the rate of core abandonment. This model allows us to examine the process by which small cores worked in the hand begin to be flaked with a bipolar technique. The value of this model is illustrated with case studies from northern and southern Australia.

Archaeological excavations at Bindjarran rockshelter in Kakadu National Park, Northern Territory, have revealed evidence of human settlement on the East Alligator River floodplain from the terminal Pleistocene through to the twentieth century. This excavation report summarises the archaeological, ethnographic and rock art research from the site, focusing on dated distributions of stone artefacts. The findings from Bindjarran conform to archaeological findings from previously investigated sites in the region and contribute to a greater understanding of Aboriginal society in this region during the Big Swamp phase, Freshwater phase and in the last 600 years.

Can archaeologists describe human population size and population growth in prehistoric Australia? This question is at the heart of some of the most intense debates about Australian prehistory: investigations into the spread of people into Australia, the rate of dispersal of people across the continent and the impact of colonisers on the environment. Australian researchers have proposed explicit models of population change based on measurements of quantities of “things” as proxies for regional and continental-wide demographic change, the most common being numbers of habitation sites and/or numbers of artefacts per millennium. Recent researchers have focused on the number of radiometric dates as the proxy for numbers of people. This paper offers an overview of existing models, concluding with a brief critique of the proposition that number of dates per unit time must be reflecting demographic patterns. We suggest that alternative and novel interpretations of large compiled radiometric databases be considered, as these data can contribute to research questions beyond those of demography. Expanding the range of research agendas that employ radiometric datasets may repay the labour invested in their compilation while allowing exploration of the diverse questions about the Australian past that remain unanswered.

A study of lithic artefacts at Haua Fteah, North Africa, documents the recycling of scrapers and burins during the period 70–15,000 BP. Rates of recycling are high during the Middle and Upper Palaeolithic but far lower during the post-LGM Epi-palaeolithic industry. These data indicate that factors other than cognitive capacity and ‘modern behaviour’ can be responsible for creating industries structured around reworking/recycling or around formalised and distinctive implement forms. In the case of Haua Fteah the proposed explanation is a shift to lithic production focussed on craft specialists in the Epi-palaeolithic, with an accompanying shift to strong normative views about socially acceptable tool forms, and probably increased functional specificity in tool use.

Throughout the Palaeolithic and across the globe small, regular cores were made using bipolar techniques, in which the object was placed between an anvil and hammer. While there has been much discussion about whether they might have been used as tools or were debris from a manufacturing process it is likely that both are true in different locations and at different times. What is distinctive about the bipolar technique is that it allows knappers to work artefacts down to a very small size, and this may facilitate the extension of both core life and tool life. In this article a model of that miniaturization process is evaluated against Holocene material from Australia and Middle Stone Age material from South Africa. It is likely that the capacity to miniaturize lithic artefacts would have been valuable in a variety of Palaeolithic contexts.

In Australia lithic technologies were entangled in the diverse processes by which people occupied environmental and social niches. Over the last few millennia, technological shifts were synchronized to paleoenvironmental transitions, but the mechanisms connecting technology and environment were multivalent. The mid-to-late-Holocene-intensified use of microliths (backed artifacts) in southeastern Australia reflects an emphasis on the production of craft objects for the reliable acquisition/processing of resources, but these artifacts were also employed to convey social information in changing times.

Geographical variation in backed artefact size and morphology has long been recognised in Australia. This paper evaluates a novel measure of symmetry that can quantify regional and continental-scale geographic patterns in backed artefact forms. The result indicates that we can construct new depictions of regional differences in Australian backed artefacts, and that evolutionary explorations of those differences are worthwhile.

This article reconsiders the early hominid “lithic niche” by examining the social implications of stone artifact making. I reject the idea that making tools for use is an adequate explanation of the elaborate artifact forms of the Lower Palaeolithic, or a sufficient cause for long-term trends in hominid technology. I then advance an alternative mechanism founded on the claim that competency in making stone artifacts requires extended learning, and that excellence in artifact making is attained only by highly skilled individuals who have been taught and practiced for extensive periods. Consequently both competency and expertise in knapping comes at a high learning cost for both the individual learner and the social group to which they belong. Those high intrinsic costs of learning created contexts in which groups selected cost-reducing forms of social learning and teaching, and in which specialization could develop. Artifacts and their manufacturing processes probably acquired functions as social signals—as honest signals of valuable capacities. The magnification of these signals, through competition between knappers and through inspiring later craftspeople, may account for a substantial amount of the accumulated elaboration visible in the archaeological record. Consequently lithic artifacts operated as material symbols from an early time in hominid evolution.

Recent excavations at the Birriwilk rockshelter in Mikinj Valley, southwest Arnhem Land, have revealed evidence for mid- to late Holocene settlement, including a major period of site use in the last millennium. The site is important to the traditional owners, with a rich oral tradition associated with 'Birriwilk', an ancestor of the Urningangk tribe, who is depicted in rock art at the site. Oral traditions link Birriwilk with an adjacent lagoon, as well as a number of other rock art sites and features in the landscape, including the renowned Ubirr complex. The Birriwilk site and vicinity are significant places to the Nayinggul family, traditional owners for the Manilikarr estate. This post-fieldwork report summarises key archaeological findings at Birriwilk, using frequencies of stone artefacts and faunal remains as proxies of occupation from ca 5000 years ago. The most intense occupation occurred within the last 700 years, a period characterised by foraging and hunting in adjacent wetland habitats, changing technological emphasis to the manufacture of bifacial quartzite points, increased artefact discard rates and increased ochre grinding. The site has little archaeological evidence of use during the last 200 years, although oral histories indicate it was visited regularly until the mid-twentieth century. The rockshelter remains an important story site today.

Changes in mythology and ritual practice are studied in southern Australia. In the early nineteenth century a reworked set of myths that have incorporated Christian motifs was grafted onto a pre-existing system of axe production, revealing the malleability of cosmological notions and the persistence of the tool production system. Transformations of mythology are displayed archaeologically in the disjunction between archaeological evidence of late Holocene axe exchange and historical statements of Aboriginal cosmology in southern Australia. This is a specific test of the widely held proposition that Aboriginal religion was stable. A number of archaeological studies now show significant, sometimes repeated, change in cosmology during the last millennium. Such studies not only illustrate the impact of external culture contact as a force generating religious change but also raise the possibility that the rate and magnitude of cosmological change may be able to be measured in ancient Australia.

Abstract Close analysis of modern movies reveals — yet archaeologists and historians have failed to understand — that the dominant representation of archaeological research and ancient human culture in mainstream cinema involves explorations of supernatural objects and events. Cinematic archaeology tends to be mythic rather than realistic in focus. Movies frequently present images of the human past that are pseudoarchaeological in the sense that these films tell the same stories as ‘alternative archaeology,’ even though they may not make an explicit claim to the truthfulness of the events depicted. This pattern is documented through a review of films employing the ancient astronaut model in which visiting aliens changed human development in the past, and through an examination of the work of writer/director Roland Emmerich who has specialized in those films. The cinematic history of these narratives is long, demonstrating that cinema does not merely reproduce popular pseudoarchaeological research, it has also contributed to the growth of these stories.

The distinctive tool called 'tula' is an endemic adaptation, which was adopted by Aboriginal people across central and western Australia, encompassing some two-thirds of the continent. The tula is a hafted tool used for working hardwoods as well as other tasks including butchery and plant-processing. The geographic spread of tulas appears to have been rapid and no antecedent form has been identified. The sudden appearance of tulas was coincident with the onset of El Nino Southern Oscillation (ENSO) conditions. While we do not yet have the data to establish an unequivocal causal link, in this paper we hypothesise that the appearance of this new and specialised tool at c.3700 BP was very likely a human response to the intensification of ENSO. This intensification resulted in increased aridity and climatic variability lasting almost 2000 years. We posit that this technological adaptation, an element of a risk minimisation toolkit, was part of a wider economic and social strategy adopted by Aboriginal people to cope with increasing climatic uncertainty. This possibility has implications for the diversity of innovation processes operating in Australia during the Holocene, which is further explored in this paper with concluding suggestions for future research. We offer this discussion as a platform for these future, and what we believe, are very necessary critical studies.