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AbstractThe automatic graphitization system (AGE3) by IonPlus is very popular among radiocarbon dating laboratories. Usually, solid samples are burnt in an elemental analyzer (EA), and the gaseous CO2is transferred for graphitization. Our system is coupled also with an isotope ratio mass spectrometer (IRMS), which measures the δ13C and δ15N of that gas. Some less routine pretreatment protocols require the production of gaseous samples and prevent the possibility of using the EA-AGE3 system, as the EA is used for solid samples only. In order to use that system, including the measurements of stable isotopes, we developed a glass tube cracker that connects to the EA. The device is routinely used in our laboratory and is mainly built from Swaglok catalog parts. We show that the background (blank) levels of a marble standard are indistinguishable between using the cracker and burning solid marble using the EA. We further demonstrate that the δ13C values are consistent and that the extraction efficiency when using the device is above 93%. Full descriptions, drawings, and working protocol are supplied.

ABSTRACTThe Minoan eruption of Santorini, Greece, is an important and often-debated chronological marker in contexts of the Eastern Mediterranean region. Among various age estimates of this event, one based on wiggle-matching of radiocarbon (14C) dates from an olive branch found in Santorini by Friedrich et al. (2006) has been widely discussed. Calibrated age estimates based on wiggle-matching of these 14C ages have been changing with improvements in the 14C calibration curve. As also shown earlier, calibration of average 14C age of multiple tree rings dated together should not be done using a single-year calibration curve. Since recent calibration curves include many single-year 14C datasets, a different approach should be considered to calibrate the average 14C age of block of multiple tree rings. Here we have demonstrated the use of multiple moving average (MA) calibration curves for calibrating the sequence of four 14C ages reported for the Santorini olive branch. The resultant calibrated ages for the Minoan Eruption are relatively younger than previous estimates and range from the late-17th century BCE to mid-16th century BCE date.

ABSTRACTVast burial fields, some with hundreds of burials, categorize the southern Levant’s Intermediate Bronze Age period (IBA). This phenomenon contrasts with a limited number of burials found from the preceding Early Bronze III period. This paper presents the first radiocarbon dating research of sampled bones from shaft tombs from five IBA burial sites across Israel: Yehud, Jebel Qaaqir, Sheikh-Danon, Hazorea, and Kefar-Veradim. Prescreening methods, including Fourier transform infrared analysis, were applied to identify best-preserved collagen in archaeological bones for radiocarbon dating. Overall, the measured date ranges cover the IBA timeline, supporting the observation that the IBA signature shaft tombs are a fundamental tradition of the IBA culture, at least in Israel. A single IBA shaft tomb at Jebel Qaaqir which contained remains of multiple humans, supplied different dates for various people, spanning over a few hundred years. These results suggest a tribal or family-oriented IBA community with a long-lasting tradition reflected in centuries of collective burial practices.

ABSTRACTThe following paper presents the results of radiocarbon (14C) dating of Middle Bronze Age (MB) contexts in Jerusalem. The dates, sampled with microarchaeology methods from three different locations along the eastern slopes of the city’s ancient core, reveal that Jerusalem was initially settled in the early phases of the period, with public architecture first appearing in the beginning of the 19th century BC and continued to develop until the 17th century BC. At that time, a curious gap in settlement is noted until the 16th century BC, when the site is resettled. The construction of this phase continued into the early 15th century BC. The dates presented are discussed in both the site-level, as well as their far-reaching implications regarding MB regional chronology. It is suggested here that the high chronology, dating the Middle Bronze Age between 2000 and 1600 BC is difficult to reconcile with dates from many sites. In contrast, a more localized chronology should be adopted, with the Middle Bronze Age continuing into the early 15th century BC in certain parts of the southern Levant, such as the region of Jerusalem.

ABSTRACTRadiocarbon (14C) dating of anthropogenic carbonates (CaCO3) such as ash, lime plaster and lime mortar, has proven a difficult task due to the occurrence of a number of contaminants embedded within the CaCO3pyrogenic binder. These include 14C-free geologic components and/or secondary phases bearing an unknown amount of 14C, and thus the alteration of the original pyrogenic isotopic signature of the material results in major age offsets when carbon recovery is performed through acid hydrolysis. Here we present a characterization/quantification approach to anthropogenic carbonates that includes Fourier transform infrared spectroscopy (FTIR), X-ray diffraction, thin section petrography, thermogravimetric analysis and scanning electron microscopy coupled with high-resolution cathodoluminescence, with which we identified the pyrogenic CaCO3fraction in an aerial lime plaster and two hydraulic mortars. The preserved pyrogenic component was then isolated by density separation and its purity checked again using FTIR. Carbon was recovered through thermal decomposition in vacuum. The resulting 14C age matches the expected age of the lime plaster, whereas hydraulic mortars are slightly offset due to the carbonation of calcium hydroxide lumps. This approach highlights the importance of a dedicated characterization strategy prior to dating and may be applied to aerial lime plasters to obtain accurate ages.

•The new charcoal assemblage from the Epipalaeolithic sequence at EQS indicates an Eastern Mediterranean vegetation and the common use of oaks (both evergreen and deciduous/semi-deciduous) and almond throughout the sequence.•New δ13C measurements of almond charcoals from EQS and EWT provide a precipitation proxy spanning from the LGM to the end of the Pleistocene suggesting that the Epipalaeolithic climate was generally more humid than at present.•Our experimental results suggest that almond is more susceptible than oak to climate change and more suitable as a palaeoclimatic proxy.

AbstractInsoluble bone collagen is one of the most common materials used for high-resolution radiocarbon (14C) dating. Unfortunately, in some bones, poor preservation of the insoluble collagen excludes the possibility of dating. During the burial of the bone the collagen sometimes degrades into peptides. These peptides are soluble in the acid used to dissolve the bone mineral. It is known that under appropriate conditions, collagen has the ability to self-assemble. Here we exploit this capability and present a method for reassembling the soluble collagen peptides in archaeological bones and dating them. We treated the acid fraction generated during the demineralization of the bone by desalting and neutralizing the solution by dialysis. During the dialysis, the soluble collagen peptides reassemble and precipitate in the dialysis bag. We used FTIR spectroscopy to determine that the precipitated material is indeed collagen. The 14C dates obtained from the reassembled collagen were compared to the dates of “standard” insoluble collagen, extracted in parallel from the same bone. Although there are some divergences of the dates, 3 out of 10 samples could have been dated only by the reassembled collagen. This shows that collagen peptides reassembly can be a valuable tool for dating bones with little or no insoluble collagen.

New radiocarbon dates are reported for Late Middle Paleolithic (MP) layers of Ciemna and Obłazowa Caves in Southern Poland. The sites present methodological challenges for radiocarbon dating related to post-depositional mixing, materials preservation, and radiocarbon measurements near the detection limit. We describe strategies to address these issues, which allowed for estimation of the timing of lithostratigraphic layers. At Ciemna, bones associated with Late MP artifacts are older than 50ka. At Obłazowa, bones associated with Late MP artifacts produced dates 50‐45kacal BP and a possible Szeletian phase occurred sometime 45‐39kacal BP. These new dates add to the regional chronology and strengthen the case that a number of distinct archaeological industries appeared in Southern Poland and Moravia during Marine Isotope Stage 3.

During the ongoing excavations of Area Q at Tel Megiddo, a variety of on-site geoarchaeological analytical methods have been used in the study of Iron Age occupations dating to the Iron Age IIA. The aim of this approach is to optimally combine macroarchaeology with microarchaeology in order to reconstruct activities that were carried out within an Iron Age urban neighborhood. The macroscopic finds indicate that this area belonged to a quarter that features both domestic and public structures. Of particular interest are (a) evidence for abandonment and spatial differentiation of activities in Level Q-5 associated with a large, well-built structure with 18 pillars; and (b) localized small-scale destruction associated with ephemeral metalworking activity related to occupation during Level Q-4. Similar approaches have been carried out at other sites in Israel (e.g., Tel Dor and Tell e?-?âfi/Gath), yet only at Megiddo have we been able to use these methods to study a large excavation area (ca. 200 m2). The results shed new light on the variability of human activities in public and domestic contexts in an urban environment, and contribute to understanding the uses of space and the phenomenon of destruction by fire.

Sun-dried mud bricks are used around the world and have been found in the Levant and Mesopotamia since the Neolithic period. Their form and composition lend important information pertaining to social and technological meaning in human cultures. Fired mud bricks are well known in the southern Levant, often identified in Bronze and Iron Age strata and used as a marker for destruction by fire (conflagration events). Only a few studies have attempted to reconstruct conflagration conditions from fired mud bricks because many variables impact the formation of the final fired brick. These include brick composition, heat intensity (i.e., maximum temperature), heat duration and firing atmosphere (i.e., oxidizing vs. reducing). The myriad combinations of these factors may result in different appearance of fired bricks. Infrared spectroscopy is one method that has been exploited quite extensively in relation to fired clay-based materials: studies were conducted on powdered sediment samples for a fixed duration and in oxidizing conditions, producing calibration curves that were then utilized for reconstruction of past maximal heat. Here we report on an experimental study of the thermal behavior of mud bricks under differing composition, heat intensity, heat duration and firing atmosphere. We carried out experiments in a furnace oven using micro-thermocouples which allowed us to simultaneously measure heat across bricks, from edge to core. The resulting mud bricks were analyzed using Fourier Transform Infrared (FTIR) spectroscopy. We identify a previously unknown thermal effect that occurs in bricks tempered with organic material while they are fired; namely a correlation between the amount of organic temper and elevation of temperatures up to 100°C above the oven chamber temperature. We record the color patterns obtained at different temperatures and duration of heating, as well as the colors obtained from heating in different atmospheres. We report that the FTIR spectrum of bricks heated in oxidizing conditions differs from that of bricks heated in reducing conditions at the same temperature. We note that the position of the main clay absorbance band cannot be used alone to infer firing temperature as its shift is not systematic. We show that combining this parameter with the width of the same band in the FTIR spectrum makes it possible to achieve better temperature reconstructions from fired bricks. Lastly, we report a small scale case study in which we tested the applicability of the experimental results to the remains of a mud brick wall unearthed within the largest known destruction event in the ancient city of Megiddo, i.e., Tel Megiddo Stratum VIA. We show that this wall was burnt as one unit, having a reduced core and oxidized outer part, where the core experienced temperatures in the range of 500–600°C and the edge 600–700°C. The detailed analysis of brick compositions carried out in this study further allows us to reconstruct the ancient bricks' preparation recipe. The results of this study bear important implications for future studies of archaeological conflagration events, and the destruction phenomenon in general.

We show that two different sources of calcite (geogenic flowstones and anthropogenic lime plaster) have complex, yet distinctive, structural disorder signatures. It is effective to identify these differences by pairing a rapid, fieldwork-compatible technique (Fourier transform infrared (FTIR) spectroscopy) with a robust laboratory-based technique (X-ray diffraction (XRD) peak width analyses). We demonstrate that crystalline domain size, microstrain fluctuations, and lattice strain each affect the FTIR spectra of calcite. To focus on each variable separately, XRD data and FTIR absorption spectra are compared among calcite samples formed by different processes. Small crystalline domain sizes cause changes to FTIR peak intensity ratios (grinding curves). However, larger microstrain fluctuations or larger lattice strain also produce similar changes. Thus, inferring structural differences from calcite FTIR spectra alone is not advisable. Instead, we advocate using FTIR grinding curves in conjunction with analyses of angle-dependent XRD peak widths using the Williamson–Hall relation. Thus, combining these two analysis techniques is more powerful and informative than using either one alone. These findings are relevant for heritage science, including archaeology.

•A pottery kiln was identified and characterized using macro- and microarchaeology.•Pottery typology and radiocarbon dating showed that the kiln was in operation for about a hundred years.•The ash in the firing chamber is composed almost entirely of phytoliths, indicating that grasses were the main fuel used.•Firing chamber temperatures resulted in the formation of phytolith slags.