Using a database of Australian archaeological radiocarbon dates ( = 2996), this paper explores three key methodological issues associated with the use of summed probability plots of radiocarbon data: 1) the minimum sample size needed for a statistically reliable plot; 2) the effect of radiocarbon calibration on the structure of these plots; and 3) the application of a taphonomic correction to such time-series data. The results identify several protocols, recommended as best-practice when using summed probability plots: 1) a minimum sample size of 500 radiocarbon dates should be used, and the sample size and the mean of the standard deviations of the radiocarbon dates (Δ ) in the sample should both be reported; 2) a moving average trendline of 500–800 years should be used to offset the effects of the calibration process; and 3) Surovell et al. “Correcting temporal frequency distributions for taphonomic bias” [ 36 (2009) 1715–1724] is explored, with modifications and temporal limits (800 sites across Australia. ► Analysis shows sample size, calibration and taphonomic loss all have an effect. ► Protocols for future production of sum probability plots are proposed. ► Comparison of plots and other archaeological indices show good correlation.
In a previous study we presented a new method that used summed probability distributions (SPD) of radiocarbon dates as a proxy for population levels, and Monte-Carlo simulation to test the significance of the observed fluctuations in the context of uncertainty in the calibration curve and archaeological sampling. The method allowed us to identify periods of significant short-term population change, caveated with the fact that around 5% of these periods were false positives. In this study we present an improvement to the method by applying a criterion to remove these false positives from both the simulated and observed distributions, resulting in a substantial improvement to both its sensitivity and specificity. We also demonstrate that the method is extremely robust in the face of small sample sizes. Finally we apply this improved method to radiocarbon datasets from 12 European regions, covering the period 8000–4000 BP. As in our previous study, the results reveal a boom-bust pattern for most regions, with population levels rising rapidly after the local arrival of farming, followed by a crash to levels much lower than the peak. The prevalence of this phenomenon, combined with the dissimilarity and lack of synchronicity in the general shapes of the regional SPDs, supports the hypothesis of endogenous causes.
Archaeological practice within the European context of heritage management is facing huge challenges in ways of recording and reproduction of ex-situ preserved sites. As a consequence of the Valletta-treaty, numbers of archived images and drawings of excavated structures as prime sources of past human activity, are exponentially growing. Contrarily to portable remains however, their future study and revision is biased by the two-dimensional character of the recorded data, rendering difficult their future reconstruction for new study or public dissemination. A more realistic three-dimensional (3D) way of recording and archiving should be pursued. In this paper the possibilities for 3D registration of archaeological features are examined in a computer vision-based approach using the PhotoScan software package (Agisoft LCC). It proved to be a scientific and cost-effective improvement compared to traditional documentation methods. Advantages can be found in the high accuracy and straightforwardness of the methodology. The extraction of an orthophoto or a Digital Terrain Model from the 3D model makes it feasible to integrate detailed and accurate information into the digital archaeological excavation plan. The visual character of 3D surface modeling offers enhanced output-possibilities allowing a better documentation of in-situ structures for future research and a higher public participation and awareness for the archaeological heritage. ► Traditional excavation recordings are biased by their two-dimensional character. ► A realistic three-dimensional way of recording and archiving need to be pursued. ► Computer vision techniques provide a cost-effective solution. ► Highly detailed and accurate 3D models of excavation data can be generated.
A major debate in prehistory revolves around the time and place of the earliest habitual use of fire and the hominin species responsible for it. Here we present a newly discovered hearth at Qesem Cave (Israel) that was repeatedly used and was the focus of hearth-centered human activities, as early as three-hundred-thousand years ago. The hearth, identified based on mineralogical and microscopic criteria, contains two superimposed use cycles, each composed of shorter episodes – possibly the earliest superimposed hearth securely identified to date. The hearth covers ca. 4 m in area making it a uniquely large hearth in comparison to any contemporaneous hearth identified thus far, possibly indicating it has been used by a relatively large group of people. In addition, the hearth is located in the center of the cave and is associated with butchered animal remains and a dense flint assemblage. The flint assemblage indicates spatially differentiated meat cutting and hide working activity areas. The central location of the hearth within the cave and the activities associated with it may reflect an embedded perception of space organization of the Qesem Cave inhabitants. Since fire was habitually used throughout the 420–200 ky sequence of Qesem Cave, where preservation conditions are alike throughout, we suggest that this unique hearth may reflect a development in nature and most probably in the intensity of fire use in Qesem Cave, from ca. 300 ka ago onwards.
The southern African MSA comprises a series of phases of unique technological innovations that fuel current models on the evolutionary processes of Anatomically Modern Humans. However, the nature and variability of these technological phases remain poorly documented. This study reports on the previously unpublished sequence of Diepkloof Rock Shelter (South Africa) and investigates the main technological changes therein, particularly emphasizing the emergence, succession and disappearance of the Still Bay (SB) and the Howiesons Poort (HP). We argue for technological change that occurred at different rates and under the influence of variable driving factors. Our model implies that the SB and the HP are not related to the influx of new populations but have regionally specific origins. Unlike the other techno-complexes, the HP at Diepkloof is subdivided into different phases (Early, Intermediate and Late) but only the upper phases resemble the so-called “classic” HP. Finally, the technological sequence of Diepkloof questions the homogeneous picture which has been so far assumed for the southern African MSA and places emphasis on the importance of exploring long regional sequences. ► Diepkloof documents distinct MSA techno-complexes, including the SB and the HP. ► Unlike other techno-complexes, the HP documents diachronic changes. ► Only the upper HP phases represent the so-called “classic” HP. ► The technological changes occurred at variable tempos and under different influences. ► The set of data suggests technological changes manifested on a local scale.
This paper explores the impact of animal manure application on the δ N values of a broad range of crops (cereals and pulses), under a range of manuring levels/regimes and at a series of locations extending from northwest Europe to the eastern Mediterranean. We included both agricultural field experiments and areas where ‘traditional’ farming is practised. Our aim is to ground-truth interpretation of δ N values in archaeobotanical crop remains as evidence of past growing conditions and husbandry practices. The results confirm the potentially radical impact of manuring on δ N values in cereals, depending on manuring level, but indicate only a slight effect on pulses, which can fix atmospheric nitrogen. The expected geographical trend towards greater δ N with increasing climatic aridity is not apparent, probably because the growing conditions for crops are ‘buffered’ through crop management. Each of these observations has fundamental implications for archaeobotanical interpretation of δ N values as evidence of land use practices and (together with analysis of bone collagen/tooth enamel in potential consumers) palaeodiet. ► We examine the affects of animal manure application on cereal grain δ N values. ► Crops grown in Syria, Germany, Denmark and the UK were given different manure levels. ► δ N values of manured grains were significantly higher compared to unmanured grains. ► The results will aid interpretation of growing conditions of ancient crop remains. ► The implications for palaeodiet and trophic level reconstructions are discussed.
The eastern Mediterranean, with its long archaeological and historical records, provides a unique opportunity to study human responses to climate variability. We review paleoclimate data and reconstructions from the region with a focus on the last 6000 years. We aim to provide an up-to-date source of information on climate variability and to outline present limitations and future opportunities. The review work is threefold: (1) literature review, (2) spatial and temporal analysis of proxy records, and (3) statistical estimation of uncertainties in present paleoclimate reconstructions (temperature, °C). On a regional scale the review reveals a wetter situation from 6000 to 5400 yrs BP (note: all ages in this paper are in calibrated years before present (i.e. before 1950), abbreviated yrs BP, unless otherwise stated). This is followed by a less wet period leading up to one of fully-developed aridity from c. 4600 yrs BP. There is a need for more high-resolution paleoclimate records, in order to (i) better understand regional patterns and trends versus local climate variability and to (ii) fill the gap of data from some regions, such as the Near East, Greece and Egypt. Further, we evaluate the regional occurrence of a proposed widespread climate event at 4200 yrs BP. This proposed climate anomaly has been used to explain profound changes in human societies at different locations in the region around this time. We suggest that although aridity was widespread around 4200 yrs BP in the eastern Mediterranean region, there is not enough evidence to support the notion of a climate event with rapidly drying conditions in this region. ► A compilation of ∼200 papers provides the current knowledge of the climate history. ► Widespread aridity developed from around 4600 yrs BP in the E Mediterranean. ► Data do not support a rapid climate event around 4200 yrs BP in the E Mediterranean. ► Our review highlights the need to improve paleoclimate reconstructions in the region.
Advances in remote sensing and space-based imaging have led to an increased understanding of past settlements and landscape use, but – until now – the images in tropical regions have not been detailed enough to provide datasets that permitted the computation of digital elevation models for heavily forested and hilly terrain. The application of airborne LiDAR (light detection and ranging) remote sensing provides a detailed raster image that mimics a 3-D view (technically, it is 2.5-D) of a 200 sq km area covering the settlement of Caracol, a long-term occupied (600 BC-A.D. 250–900) Maya archaeological site in Belize, literally “seeing” though gaps in the rainforest canopy. Penetrating the encompassing jungle, LiDAR-derived images accurately portray not only the topography of the landscape, but also, structures, causeways, and agricultural terraces – even those with relatively low relief of 5–30 cm. These data demonstrate the ability of the ancient Maya to modify, radically, their landscape in order to create a sustainable urban environment. Given the time and intensive effort involved in producing traditional large-scale maps, swath mapping LiDAR is a powerful cost-efficient tool to analyze past settlement and landscape modifications in tropical regions as it covers large study areas in a relatively short time. The use of LiDAR technology, as illustrated here, will ultimately replace traditional settlement mapping in tropical rainforest environments, such as the Maya region, although ground verification will continue to be necessary to test its efficacy.
Human and domesticate animal bone collagen δ N values in prehistory differ generally by 3‰ or more from Neolithic to post- Roman times in Northwest Europe, leading to an assumed dietary animal protein fraction of 60–80% using a standard interpretation of δ N values. We examine the assumptions on which this model rests and the limitations of our knowledge in the analysis of δ N values in archaeology. We have developed a set of models which, with small changes made in assumptions (on the order of 1‰), can produce substantially lower estimates of the dietary animal protein fraction for given δ N values. We consider the implications of various dietary animal protein fractions on agricultural carrying capacities and human population densities in prehistory.
Microscopic signatures have previously been used to emphasize the similarities of butchery and trampling marks. The experimental background applied to differentiate both types of marks has been rather limited and authors have sometimes reached conflicting conclusions. This is partly due to methodological reasons: some authors have used very high magnification to examine microscopic features, whereas others have relied on more reduced magnification. Likewise, some experiments have exposed bones to trampling for reduced periods (minutes) whereas others have used longer time periods (hours). The present study stresses that the use of a scanning electronic microscope is not practical for identifying the impact of butchery and trampling marks in complete bone assemblages. It also emphasizes that previous studies have not addressed all the possible variables that could potentially be used to discriminate these marks, nor have they quantified the morphological patterns of each type of mark. Here we present a multivariate analysis of more than a dozen variables and show that butchery and trampling marks have very distinctive microscopic morphology. We advocate the use of a low magnification approach (≤40×), which can enable the analysis of complete assemblages using either hand lenses or binocular lenses. We also show the morphological criteria that differentiate butchery cut marks made with simple and retouched tools. We show that whereas complete discrimination of marks is impossible due to some degree of overlap, the list of criteria derived through multivariate analyses can be confidently used to correctly differentiate butchery and trampling marks in more than 90% of cases.
The logic of using summed radiocarbon ( C) calibrations (cumulative probability density functions for large numbers of calibrated C dates) as proxies for past populations rests on the presumption of a proportional relationship between population size and the production, and subsequent preservation, recovery, and analysis, of C-datable material. Critiques of this approach have generally focused on the various problems that may undermine the validity of this assumption. Here, instead, we presume a perfect correspondence between population size and the quantity of datable material produced at any given time, and explore the question of how well summed C calibrations can track demographic changes under such ideal circumstances. We introduce a method of generating a random sample of simulated C determinations, from a specified distribution, with variable data densities and measurement errors. In other words, we generate a random sample of C dates not from an ideal statistical distribution but rather using a defined population curve to determine the probability distribution from which the calendar dates of the simulated C samples are drawn. We generate simulated C ages for these samples, calibrate them, and sum those calibrations. We compare the resulting proxy population curve to the known population distribution from which it was generated, to see whether known population fluctuations are unambiguously visible on a proxy curve derived from C data sets that are realistic in terms of the number and precision of the C determinations included. Results highlight 1) the critical role played by the magnitude and duration of any population fluctuation, and 2) the importance of sample size, and the reality that the numbers of samples required to detect significant population changes are generally far higher than those available to researchers proposing demographic reconstructions on the basis of literature searches for radiocarbon dates. We conclude that even if archaeological C data sets could be corrected for taphonomic filters and research biases, demographic signals would be difficult to distinguish from statistical noise in summed probability distributions. We suggest that simulation studies should be integral components of any attempt to reconstruct prehistoric demography from C dates.
Image-based 3D modeling has already proven its value for the recording of excavations, however until now its application has remained rather small-scale. We have examined the possibilities and limitations of image-based 3D modeling in the recording of an entire excavation, and its impact on the workflow of the excavation process and the post-excavation processing. Our results suggest that image-based 3D modeling can be an excellent and suitable method for the recording, documentation and visualization of the excavated archaeological heritage. It offers great possibilities for increasing the quality of the archived archaeological excavation record. The high-resolution geometric information allows a straightforward quantification of the data. However it also brings along new challenges, including a change in the workflow of the excavation and the post-excavation process. Although there are limitations, these are greatly surpassed by the possibilities of the method. We believe that image-based 3D modeling can cause a(n) (r)evolution in archaeological excavation practice.
Comprehensive review of archaeological data shows that Sahul (Pleistocene Australia-New Guinea) was first occupied by humans ca. 47 ka (47,000 years ago); evidence for earlier arrival is weak. Colonizing populations remained low – perhaps two orders of magnitude below those estimated at European contact – for many millennia, and were long restricted to relatively favorable habitats. Though human arrival coincided with changes in native flora and fauna, these were mainly the products of climatic factors, not human interference. The genetic makeup of founding populations and their arrival date are consistent with the Late Dispersal Model of anatomically modern humans beyond SW Asia, beginning ca. 50 ka. Early Dispersal Models (120–70 ka) are not refuted, but draw no support from the Sahul record as currently understood.
To date, aerial archaeologists generally apply simple rectification procedures or more expensive and time-consuming orthorectification algorithms to correct their aerial photographs in varying degrees for geometrical deformations induced by the topographical relief, the tilt of the camera axis and the distortion of the optics. Irrespective of the method applied, the georeferencing of the images is commonly determined with ground control points, whose measurement and identification is a time-consuming operation and often limits certain images from being accurately georeferenced. Moreover, specialised software, certain photogrammetric skills, and experience are required. Thanks to the recent advances in the fields of computer vision and photogrammetry as well as the improvements in processing power, it is currently possible to generate orthophotos of large, almost randomly collected aerial photographs in a straightforward and nearly automatic way. This paper presents a computer vision-based approach that is complemented by proven photogrammetric principles to generate orthophotos from a range of uncalibrated oblique and vertical aerial frame images. In a first phase, the method uses algorithms that automatically compute the viewpoint of each photograph as well as a sparse 3D geometric representation of the scene that is imaged. Afterwards, dense reconstruction algorithms are applied to yield a three-dimensional surface model. After georeferencing this model, it can be used to create any kind of orthophoto out of the initial aerial views. To prove the benefits of this approach in comparison to the most common ways of georeferencing aerial imagery, several archaeological case studies are presented. Not only will they showcase the easy workflow and accuracy of the results, but they will also prove that this approach moves beyond current restrictions due to its applicability to datasets that were previously thought to be unsuited for convenient georeferencing. ► Aerial archaeological oblique frame images suffer serious geometrical deformations. ► Accurate orthophoto creation is essential but costly and time-consuming. ► New computer vision-based approach for orthophoto and DSM production is examined. ► 3 case studies indicate the multiple advantages over conventional approaches. ► Future improvements are discussed.
Projectiles have enjoyed a lot of attention over the last few years as an indication of the existence of hafted hunting technology and as one of the arguments in discussions on complex human behaviour. More and more frequently, the identification of projectile points is based on a limited range of macro-fractures, despite the diversity and variability in wear features from projectile use. Such a methodological simplification does not support the wide-ranging interpretations often proposed. We address the many difficulties involved in reliably identifying projectiles and we suggest how these should preferably be dealt with.
While it is true that the use of fire is undoubtedly an important behavioral trait, fire can also leave important traces in archaeological deposits, including altering previously deposited sediments and artifacts. The set of controlled experiments reported here do not focus on fire per se, but rather on the effects of some of the most important variables underlying the transfer of heat to subsurface sediments. These variables, including temperature, duration, sediment type, moisture, and mineralogy, are altered here in ways that essentially bracket the range of conditions under which past fires may have existed. The results show that sediments as much as 10 cm directly below a heat source routinely reach temperatures of 200 °C, with higher temperatures and greater depth of heat transfer possible with longer durations or higher surface temperatures. One of the implications of these results is that a surface can produce substantial thermal-alterations of archaeological artifacts and sediments deposited much earlier in the sequence. Likewise, there are significant implications for the analyses and chronometric dating of thermally altered sediments and burned artifacts.
Recently, there has been significant interest in the use of portable X-ray fluorescence spectrometers (pXRF) for cultural materials applications, especially ceramics and sediments. Although modern pXRF spectrometers have lower detection limits and better resolution than those of decades past, portable instruments remain subject to the same limitations as bench-top ED-XRF instruments, particularly with respect to sample preparation, instrument calibration, and ability to accurately quantify low-Z elements. In this paper, we evaluate the strengths and limitations of pXRF analysis for the quantitative compositional analysis of archaeological ceramics and sediments and propose an analytical protocol and calibration designed to optimize pXRF performance for these materials.
Surveys for archaeological sites in the De Hoop Nature Reserve, southern Cape, South Africa resulted in the discovery of a cave complex comprising two locations, Klipdrift Cave and Klipdrift Shelter. Excavations commenced in 2010 with Later Stone Age deposits initially being recovered at the former site and Middle Stone Age deposits at the latter. The lithic component at Klipdrift Shelter is consistent with the Howiesons Poort, a technological complex recorded at a number of archaeological sites in southern Africa. The age for these deposits at Klipdrift Shelter, obtained by single grain optically stimulated luminescence, spans the period 65.5 ± 4.8 ka to 59.4 ± 4.6 ka. Controlled and accurate excavations of the discrete layers have resulted in the recovery of a hominin molar, marine shells, terrestrial fauna, floral remains, organic materials, hearths, lithics, ochre, and ostrich eggshell. More than 95 pieces of the latter, distributed across the layers, are engraved with diverse, abstract patterns. The preliminary results from Klipdrift Shelter presented in this report provide new insights into the Howiesons Poort in this sub-region and contribute further to ongoing knowledge about the complex behaviours of early Homo sapiens in southern Africa. Excavations at the Klipdrift Complex will continue in the future.
Graphic and metric archaeological documentation is an activity that requires the capture of information from different sources, accurate processing and comprehensive analysis. If monitoring of the state of conservation is required, this task has to be performed before intervention, during and after the completion of the works in a repetitive way. This paper presents the use of terrestrial laser scanning (TLS) in order to effectively produce, prior to intervention, accurate and high-resolution 3D models of a cave with engravings dating back to the Upper Palaeolithic era. The processing of the TLS data is discussed in detail in order to create digital surface models. The complexity of the cave required the integration of two techniques, TLS and close range photogrammetry to yield not only traditional drawings such as sections and elevations, but also photo-realistic perspective views and visual navigation worlds fully operational in 3D environments. This paper demonstrates the potential of integrating TLS and close range photogrammetry to provide both accurate digital surface models and photo-realistic outputs. This processed data can be used to systematically improve archaeological understanding of complex caves and relief panels of prehistoric art with tiny engravings.
A multi-disciplinary study assessing the evidence for agriculture in Neolithic Ireland is presented, examining the timing, extent and nature of settlement and farming. Bayesian analyses of palaeoenvironmental and archaeological C data have allowed us to re-examine evidential strands within a strong chronological framework. While the nature and timing of the very beginning of the Neolithic in Ireland is still debated, our results – based on new Bayesian chronologies of plant macro-remains – are consistent with a rapid and abrupt transition to agriculture from c. 3750 cal BC, though there are hints of earlier Neolithic presence at a number of sites. We have emphatically confirmed the start of extensive Neolithic settlement in Ireland with the existence of a distinct ‘house horizon’, dating to , lasting for up to a century. Cereals were being consumed at many sites during this period, with emmer wheat dominant, but also barley (naked and hulled), as well as occasional evidence for einkorn wheat, naked wheat and flax. The earliest farmers in Ireland, like farmers elsewhere across NW Europe, were not engaged in shifting cultivation, but practised longer-term fixed-plot agriculture. The association between early agriculture and the Elm Decline seen in many pollen diagrams shows that this latter event was not synchronous across all sites investigated, starting earlier in the north compared with the west, but that there is a strong coincidence with early agriculture at many sites. After this early boom, there are changes in the nature of settlement records; aside from passage tombs, the evidence for activity between 3400 and 3100 cal BC is limited. From 3400 cal BC, we see a decrease in the frequency of cereal evidence and an increase in some wild resources (e.g. fruits, but not nuts, in the records), alongside evidence for re-afforestation in pollen diagrams (3500–3000 cal BC). Changes occur at a time of worsening climatic conditions, as shown in Irish bog oak and reconstructed bog surface wetness records, although the links between the various records, and assessment of causes and effects, will require further investigation and may prove complex. This period seems to have been one of environmental, landscape, settlement and economic change. The later 4th millennium BC emerges as a period that would benefit from focused research attention, particularly as the observed changes in Ireland seem to have parallels in Britain and further afield.