ESR dose response of Al center measured in quartz samples from the Yellow River (China): Implications for the dating of Upper Pleistocene sediment

The ESR dating method requires to describe the evolution of the ESR signal intensities vs. increasing gamma doses, then to extrapolate the equivalent dose of radiation received by the sample since its deposition using mathematical fitting. The function classically used to describe the growth curves of ESR aluminium signal in quartz was recently discussed and challenged for Lower Pleistocene sediments. In the present work, some alluvial sediments sampled in Upper Pleistocene fluvial terraces of the Yellow River system (China) permit us to test the application of another extrapolation function (linear + exponential) recently proposed for Lower Pleistocene sediments. The equivalent doses obtained here for the recent deposits of the Yellow River system and the corresponding ages are promising and indicate the potential of ESR to date quartz deposits from Upper Pleistocene times.     

LUMINESCENCE DATING OF SEDIMENTS—THE DETECTION OF HIGH EQUIVALENT DOSE GRAINS USING AN IMAGING PHOTON DETECTOR*

In this paper we describe quantitative measurements on the thermoluminescence of many single grains, made with an imaging photon detector. In several of the sediments examined a few bright grains were found which had a high equivalent dose (ED). Physical measurements made on these grains using binocular microscopy and analytical scanning microscopy enabled several possible explanations for the causes of the high ED grains to be rejected. Insufficient bleaching at deposition or the intrusion of grains from an older sediment were identified as the most probable explanation for these grains.     

THE EFFICIENT COMPUTATION OF UNBIASED MAHALANOBIS DISTANCES AND THEIR INTERPRETATION IN ARCHAEOMETRY*

This paper argues for cross-validation to reduce bias in estimating Mahalanobis distances of individuals to groups, a particular problem with small sample sizes. Formulae for the efficient computation of cross-validated distances, which avoid excessive matrix inversion, are given. The use of Mahalanobis distances as measures of consistency, or as indications of outlying values, is described. The little-known technique of gamma plotting is outlined and discussed as an aid to interpreting distances in these terms. Both cross-validation and gamma plotting are illustrated in an example on marble composition.     

Luminescence dating of young coastal deposits from New Zealand using feldspar

A new measurement protocol has been tested on K-feldspars from Whanganui Inlet and Parengarenga Harbour, New Zealand. A Single Aliquot Regenerative (SAR) dose protocol, using two successive infrared (IR) stimulations (post-IR IR SAR protocol) is setup for these young (<1000 years) coastal sediments. Significant anomalous fading (g _2days =7 %/decade) is observed using the conventional IR signal measured at 50°C. In contrast, the fading rate of the IR signal measured at elevated temperature (150°C) after the IR stimulation at 50°C (a post-IR IR signal) is not significant (g _2days ≤ 1 %/decade). Surprisingly low residual infrared stimulated luminescence (IRSL) signals were observed for a surface sample, suggesting that accurate ages as young as ∼50 years can be obtained for these recent deposits. IRSL ages ranging between 48±6 years and 1050±50 years are obtained from six samples, indicating that sediment accumulation has occurred at the two sites during the last millennia, despite a falling trend in relative sea-level in Whanganui Inlet and a stable relative sea-level at Parengarenga Harbour.     

Dating mortar by optically stimulated luminescence: A feasibility study

Quartz is the datable component in mortar. Although its luminescence properties are very well studied, the problem of mortar dating arises from a low level of optical bleaching. In order to reduce the time consuming efforts for dating lime mortar in monuments by optically stimulated luminescence, we investigated the most suitable methods of dose and dose rate determination, and we explored tests which are suitable to predict the datability of a given material. Reverting to the large number of publications on sedimentary partially bleached quartz we found linear modulation techniques especially useful, equally we also recommend the determination of the level of optical depletion before starting analyses. Single grain analysis is regarded as an ultimate but infallible tool to date very poorly bleached quartz from mortar. Dose rate measurements need to take into account the radioactive equilibrium of the uranium decay and the short range inhomogeneity of the environmental gamma radiation field: gamma spectrometry and on-site TLD measurements are best suited.     

Damage caused by insects during the mummification process: an experimental study

The process of mummification had been known since the Fourth Dynasty of the Old Kingdom (ca. 2600 bc) and continued to develop throughout ancient Egyptian history. Although mummification protected the body from decay, especially by microbes, some mummification techniques left the body susceptible to insect attack. Certain types of insects have been detected in the mummies. In scholarly publications, most authors have dealt with microorganisms, while few have concerned themselves in depth with the effect of insects on the mummies. This study aims to discuss the significance of insects and the changes they affected to the mummies during embalming. To achieve this goal, experiments were carried out replicating various mummification techniques using albino Wistar rats. Analysis and investigative techniques used included visual observation, Fourier transform infrared spectroscopy, investigation of the surface morphology by a scanning electron microscope, and color change by a spectrophotometer. The following insects could be identified as being present during the second and third processes of mummification: Dermestes maculatus, Necrobia rufipes, Saprinus gilvicornis, Chrysomya albiceps, Wohlfahrtia magnifica, and Attagenus fasciatus. In addition, the majority of our findings confirmed that the degradation by insects increased with the second and third methods of mummification. Finally, the experimental study conducted using the mummification techniques of the New Kingdom (ca. 1570–1070 bc) indicated that they were more resistant to insect attack than the other types.     

Radiocarbon dating by the accelerator technique

Radiometric dating of archaeological samples by the accelerator mass spectrometry (AMS) technique is well established today. The main advantage of this method compared to the old decay counting procedure is the small sample size (1 mg carbon equivalent weight) needed to carry out a dating. The basic principles as well as the present status of the technique are presented. Experiences from the first year of routine measurements in the Uppsala laboratory are discussed and some examples of the material analysed are given.     

Palaeontology of the Cerros Bayos section,Roca Formation (Danian), La Pampa Province,Argentina

Palynofloras from an outlier of Tertiary sediments in the One Tree Hill area north of Adelaide are nonmarine and correlate with similar assemblages from Middle Eocene North Maslin Sands from Maslin Bay and Golden Grove. Although there are similarities with time-equivalent Lower Nothofagidites asperus Zone palynofloras in the Gippsland Basin, a number of species in the South Australian palynofloras do not extend below the Late Eocene in the Gippsland sequences. This indicates earlier appearances for these species in southcentral Australia. The sediments overlie a highly weathered bedrock palaeosurface, indicating that a phase of significant weathering occurred prior to the Middle Eocene. A number of selected taxa are illustrated and their distribution in the palynofloras is discussed. Two new species, Proteacidites mildenhallii and Proteacidites parrawirrensis, are described and one species, Rhoipites byfieldensis, is emended.     

Concordant <Superscript>210</Superscript>Pb and <Superscript>137</Superscript>Cs ages of black sea anoxic unconsolidated sediments

Two independent geochronologic radiometric methods: ¹³⁷Cs and ²¹⁰Pb were used to determine the sedimentation rate and subsequently to date the oldest sediments of a 50 cm core containing unconsolidated sediments collected at a depth of 600 m below sea surface in the anoxic zone of the Western Black Sea, off the Romanian town of Constanta. Both methods gave coincident value within experimental uncertainties of 0.42±0.20 mm·y⁻¹ for ¹³⁷Cs and 0.49±0.03 mm·y⁻¹ in the case of ²¹⁰Pb, within the Constant Initial Concentration model, which gave for the lower most sediments an age of 1.00±0.01 ka. The constant sedimentation model as well as the possible causes of observed discrepancy between experimental uncertainties are discussed.     

The chronology of the Neolithic sequence at Dikili Tash,Macedonia, Greece: TL dating of domestic ovens*

The chronological sequence of a major reference site for Neolithic periods in southeastern Europe and the Aegean, Dikili Tash (Macedonia, Greece), has been reassessed by TL. Baked adobe material samples extracted from domestic ovens, directly associated with specific occupational levels, have been studied. The fine‐grain technique has been used for equivalent dose determination. K, U and Th contents and the equilibrium state of U‐series have been measured by low‐background gamma spectroscopy. Since the archaeological levels were already partly excavated, the environmental dose‐rate was evaluated by a reconstruction technique combining laboratory analysis and on‐site measurements. The TL results (weighted average of multiple age determination, oven 400, middle of the Dikili Tash I (DT‐I) phase, 5500 ± 320 bc ; oven 600, end of DT‐I, 4920 ± 310 bc ; house 3, DT‐II, 4260 ± 280 bc ; house 4, DT‐II, 4510 ± 410 bc ) are in general agreement with the timeframe deduced from previous radiocarbon dates. This convergence strengthens the settlement's chronology, established now by independent dating methods.     

Virtual assembly of pottery fragments using moiré surface profile measurements

Reconstruction of archaeological monuments and potteries from fragments found at archaeological sites is a tedious task that requires many hours of work from archaeologists and restoration personnel. Excavations from famous archaeological sites in Jordan such as Petra, Jerash, Um Qeis, Ajlun etc. indicated civilization throughout centuries, from prehistoric periods, up to present. The restoration process is tedious and lengthy due to the mass of fragile fragments which consists of thousands of sherds found at excavation sites. An approach is the use of shadow moiré experimental technique to obtain the 3D model of pots from 3D measurements of the surface profile using the photos captured. This method is a non-destructive optical technique used for visual surface inspection, and surface profile measurements. The approach is simple, requires minimal mathematical calculations and reduces the risk of frequent handling of the fragile sherds, because the photos can be captured using a simple experimental setup in the site. Matching of fragments and aligning them geometrically is based on matching the profiles and edges of the broken parts virtually. This virtual assembly technique may assist the archaeologists as much as possible in solving their task with minimum time and minimum damages to fragments. The technique, of course, does not completely replace the archaeologist, but provides a useful estimation of valid fragment combinations, and accurately measures fragment matches. It also simplifies modeling the pots virtually using 3D-MAX modeling software to obtain the missing pieces.     

Rock surface luminescence dating of prehistoric rock art from central Iberia

Rock art paintings are notoriously difficult to date numerically. Recently, luminescence dating has been shown to provide reliable rock surface burial ages in various archaeological settings. Here we use the cross-cutting relationship between a fallen rock and two paintings of the Iberian Levantine (older) and Schematic (younger) styles to constrain the age of the paintings by dating the rockfall event using rock surface luminescence dating. Infrared-stimulated luminescence (IRSL) signals as a function of depth into the buried face of the talus border indicate that the IRSL signal measured at 50°C (IR₅₀) was sufficiently reset to a depth of about 1.6 mm prior to burial. An uncorrected IR₅₀ age of 1.6 ± 0.2 ka was calculated for the rockfall event by dividing the surface equivalent dose (D_e) by the total dose rate. This age was corrected using both conventional and field-to-laboratory saturation approaches to yield indistinguishable ages of 2.7 ± 0.5 and 2.9 ± 0.3 ka, respectively. Since the panel with Schematic art was first available to the artist after the rockfall, we conclude the Schematic rock art at Villar del Humo is younger than ~2.9 ka. The Levantine rock art was painted on a panel constrained by the talus boulder before detachment, and so it is likely to be older than ~2.9 ka.     

Finding a Relatively Flat Archaeological Site with Minimal Ceramics: A Case Study from Iraqi Kurdistan

ABSTRACT

We present a new technique to detect flat archaeological sites with minimal ceramics using an unmanned aerial vehicle that maps surface stone concentrations. Methods deployed include point pattern analysis of stone concentrations and a machine-learning technique using unsupervised classification of visible stone signature qualities, which are used in simple linear regressions to compare with geophysical and ceramic surface survey results of a site in Iraqi Kurdistan. There is a stronger fit (r^2?=?0.77) between surface stone concentrations and architecture identified by geophysical measurement, while surveyed ceramics show a weaker fit to defined architecture (r^2?=?0.31). Surface stone concentrations are potentially a better proxy than ceramics for determining the presence of past settlement in regions where stone was commonly used, sites are relatively flat, and ceramics are found in low concentrations. The methods advanced here can be scaled to wider areas, particularly in mountainous regions, where surface stone features are present.     

Constraints on the precision of SAR in equivalent dose estimations close to saturation in quartz

Difficulties in evaluating accurate equivalent doses for Late Quaternary sediments from the south coasts of Greece arose in the course of SAR measurements. Large scatter among apparent equivalent doses perplexed the evaluation of accurate mean estimates in circumstances where very large doses were involved. Besides, dose recovery experiments revealed that when intersection of the natural signal occurs onto the saturating segment of the growth curve, a distinct relationship between D_e and growth curve shape occurs. At very low slope angles, SAR tends to overestimate the recovered dose. The mechanism which controls the spread in equivalent dose estimation is investigated.     

DETECTING FORGERIES AMONG ANCIENT GOLD OBJECTS USING THE U,Th–4He DATING METHOD*

Forgeries of ancient gold objects are prevalent in almost every collection and some public exhibitions in the past have been exposed as containing forgeries to an embarrassing extent. This situation comes from the fact that it is sometimes impossible to unequivocally recognize forgeries based on their patina or manufacturing and decoration characteristics. We demonstrate that for 13 ancient gold objects the time of their last melting process can be estimated using the U,Th–⁴He dating technique. The extremely small quantities of radiogenic ⁴He found, due to the young age and small sample size, require the use of a specially designed ultrasensitive mass spectrometer. We show that the proposed method is a powerful, and the only, quantitative tool in archaeometry for discriminating between fake and genuine ancient gold objects.     

Real‐time quadrupole mass spectrometer analysis of gas in borehole fluid samples acquired using the U‐tube sampling methodology

Sampling of fluids in deep boreholes is challenging because of the necessity of minimizing external contamination and maintaining sample integrity during recovery. The U‐tube sampling methodology was developed to collect large volume, multiphase samples at in situ pressures. As a permanent or semi‐permanent installation, the U‐tube can be used for rapidly acquiring multiple samples or it may be installed for long‐term monitoring applications. The U‐tube was first deployed in Liberty County, TX to monitor crosswell CO₂ injection as part of the Frio CO₂ sequestration experiment. Analysis of gases (dissolved or separate phase) was performed in the field using a quadrupole mass spectrometer, which served as the basis for determining the arrival of the CO₂ plume. The presence of oxygen and argon in elevated concentrations, along with reduced methane concentration, indicates sample alteration caused by the introduction of surface fluids during borehole completion. Despite producing the well to eliminate non‐native fluids, measurements demonstrate that contamination persists until the immiscible CO₂ injection swept formation fluid into the observation wellbore.     

Deformation of Ancient Buildings inferred by Terrestrial Laser Scanning methodology: the Cantalovo church case study (Northern Italy)*

The study of the health of a building connects humanistic and scientific research, and a complete characterization can be achieved by integrating all the available historical documentation, architectural and metrological studies, as well as laboratory and in situ analyses of the materials. A contactless, non‐invasive surveying technique such as terrestrial laser scanning (TLS) allows the acquisition of dense and accurate geometric and radiometric (electromagnetic measurements such as signal intensity) information about the observed surface of the building, which can be easily integrated with data provided by high‐resolution digital imaging. The early Christian Cantalovo church was surveyed for the first time in April 2011, by means of the ILRIS‐3D ER very long range scanner. The second and last survey was performed in June 2012, after the main shocks of the Emilia earthquake seismic sequence. A very long range instrument is suitable for fast, simple and independent measurements, due to its technical characteristics and, for this reason, is easily usable for accurate surveying in emergency conditions. The main results are obtained by applying a data analysis strategy based on the creation of TLS‐based morphological maps computed as point‐to‐primitive differences, which allow the creation of a deformation map and its evolution in time.     

Towards the application of desorption electrospray ionisation mass spectrometry (DESI-MS) to the analysis of ancient proteins from artefacts

The detection and identification of protein residues from archaeological artefacts has been the subject of considerable controversy over the past two decades, this controversy spurring the application of a range of different analytical methods. Part of the debate surrounds the ability of the methods to uniquely identify original proteins. Another is the apparent contradiction between the ease of extraction in the laboratory of residues that have managed to survive in sediment over millennia; some studies use simple solvents including water, whilst others claim that efficient extraction requires the destruction of the artefact.Desorption electrospray ionisation mass spectrometry (DESI-MS) offers the potential to directly analyse proteins bound to the surface of artefacts. The method permits desorption of analytes under ambient conditions directly from a wide range of surfaces with little or no sample preparation. This has already led to its application in a range of areas, including forensic analysis of trace levels of narcotic drugs. It does not require destruction of the artefact (e.g. by drilling or dissolution) and can work in concert with other methods (for instance it could be used as a screening tool prior to lipid extraction).Here we report the construction of a DESI-MS interface and consider the potential of the method to contribute to the debate surrounding the preservation of proteins on artefacts. The DESI-MS interface was fitted to a conventional ion trap mass spectrometer and tested using peptides and proteins artificially applied to the surface of flint flakes and potsherd samples. A range of intact proteins was analysed; the DESI interface identified test proteins up to a maximum molecular weight of approximately 20 kDa. Peptides generated from these and larger proteins could be detected using DESI-MS following tryptic digestion in situ. The collected data allowed identification of the originating proteins. The potential applications to archaeological science of this new analytical tool are discussed.     

Neosecoptera,a new insect suborder based on specimen discovered in the Late Carboniferous of Tasmania

Psychroptilus burrettae gen. et sp. nov., from the Late Carboniferous of Tasmania, combines characters of the insect orders Palaeodictyoptera and Megasecoptera. Psychroptilus is referred to the Megasecoptera because it lacks paratergal processes on the pronotum, and because its wing venation is simple, with reduced cross veins. However, its wings are not narrowed at their bases, but are as broad as those of the Palaeodictyoptera. It is placed in a new suborder of the Megasecoptera, the Neosecoptera. This suborder differs from the Suborders Eumegasecoptera and Protohymenoptera in having: 1, broad wings that are not narrowed at base; 2, the hind wing slightly broader than the fore wing; and 3, anal veins that all arise from close to the wing base. The insect is possibly the oldest recorded in the southern hemisphere although age determinations of this and the only other known probable Late Carboniferous species, Hadentomoides dwykensis Riek, are not precise. The inclusion of the insect fossil in varve-like sediments and the very few associated fossil species, are indicative of a very cold habitat either at or adjacent to the area producing the sediments. The great majority of insect fossils are associated with abundant plant remains or other fossils indicative of warm conditions in the area of sedimentation. None is recorded from an area apparently as cold as that under which Psychroptilus burrettae was preserved.     

Lichenometric constraints on the age of the Huashan Grottoes, East China

Lichenometry is a method of dating that has been widely used in glaciated areas for determining the minimum age of exposure of a geomorphic landform during the late Holocene. This paper presents a regional calibration data set of lichen thallus sizes versus rock surface ages for the Huashan area, East China, based on measurements of yellow-green Rhizocarpon lichens on the known-age substrates at eight sites. An empirical relationship between thallus sizes and rock surface ages was established using both the traditional regression and the Bayesian approaches. Using the Bayesian calibration, the minimum age of the Huashan Grottoes was dated from 450 ± 60 to 330 ± 60 years ago, corresponding to the late Ming Dynasty (AD 1477–1632). These dates are generally consistent with those predicted from the regression-based linear growth curve. Our results suggest that applications of this technique can be safely extended to the non-glaciated areas.