• The Date of the Minoan Santorini Eruption: Quantifying the “Offset”

      Höflmayer, Felix (Department of Geosciences, The University of Arizona, 2012-10-15)
      Despite many recent attempts to settle the dispute concerning the absolute date of the Minoan Santorini eruption, there are still differences between some archaeologists and scientists on the absolute dates and the reliability of radiocarbon dating. The recent publication of over 200 new 14C dates for dynastic Egypt rules out a major flaw in the historical chronology of Egypt and proves the reliability of 14C dating in the Nile Valley. Therefore, the student of Aegean archaeology and eastern Mediterranean interconnections is still confronted with an archaeologically based conventional, or “low,” chronology and a 14C-backed “high” chronology. New 14C determinations from different sites of the Aegean support the high chronology for the Late Minoan (LM) IA, while recent re-evaluation of LM IB determinations are slightly higher but more or less in agreement with archaeological estimations. The present contribution reviews archaeological and scientific data for the LM IA period and argues that a reduced (~30 to 50 yr) offset between archaeological and 14C dates for the Minoan Santorini eruption may be possible, thus offering new perspectives for potential solutions for this problem.
    • The Chronology of Tell el-Daba: A Crucial Meeting Point of 14C Dating, Archaeology, and Egyptology in the 2nd Millennium BC

      Kutschera, Walter; Bietak, Manfred; Wild, Eva Maria; Bronk Ramsey, Christopher; Dee, Michael; Golser, Robin; Kopetzky, Karin; Stadler, Peter; Steier, Peter; Thanheiser, Ursula; et al. (Department of Geosciences, The University of Arizona, 2012-10-15)
      Radiocarbon dating at the Tell el-Daba site in the Nile Delta has created an enigma for many years. Despite great efforts, the difference of about 120 yr between the chronology based on 14C dates and the one based on archaeological evidence linked to the Egyptian historical chronology has not been solved. In order to foster open discussions on this discrepancy, we present here the results of 40 14C accelerator mass spectrometry (AMS) measurements on short-lived plant material assigned to 14 different phases of the Tell el-Daba excavation, spanning 600 yr (about 2000–1400 BC). On the one hand, the recently established agreement between 14C dates and dynastic Egypt (Bronk Ramsey et al. 2010) makes it unlikely that the problem lies in the 14C dates and/or the Egyptian historical chronology. On the other hand, the extensive archaeological evidence from Tell el-Daba linked to many different cultures in the eastern Mediterranean and to the Egyptian historical chronology provides strong evidence for an absolute chronology shifted by about 120 yr with respect to the 14C dates.
    • Lime Mortar and Plaster: A Radiocarbon Dating Tool for Dating Nabatean Structures in Petra, Jordan

      Al-Bashaireh, Khaled; Hodgins, Gregory W. (Department of Geosciences, The University of Arizona, 2012-10-15)
      This research aims at radiocarbon dating 2 structures of archaeological interest from Petra, south Jordan, using lime plaster and mortar. Initially, the samples’ content of calcareous contamination was examined by petrography and cathodoluminescence. In order to date clean lime binders, the samples were gently crushed and 63–45 µm powders were collected by dry sieving, then the CO2 gases, collected by a hydrochloric acid hydrolysis of the powders, were dated. The interpreted 14C dates clarify the chronology of the studied structures, show an agreement with the archaeological and historical data, and may indicate the efficiency of the cleaning and hydrolysis procedures.
    • Interpreting Radiocarbon Dates from Neolithic Halai, Greece

      Facorellis, Yorgos; Coleman, John E. (Department of Geosciences, The University of Arizona, 2012-10-15)
      Archaeological investigations at Halai, a small city-state on the sea coast of East Lokris in Greece, have been carried out since 1986 by the Cornell Halai and East Lokris Project (CHELP). The town’s acropolis, first inhabited in the Neolithic period, was in Greco-Roman times a political and cultural center controlling and serving a considerable territory. Radiocarbon dating of charred material unearthed from Neolithic deposits indicate that the Neolithic occupation probably lasted from about 6000 to 5300 BC. Details of dating are somewhat problematic, however, because of outlying determinations and lack of close agreement between determinations from the same or stratigraphically comparable material.
    • State Formation in Judah: Biblical Tradition, Modern Historical Theories, and Radiometric Dates at Khirbet Qeiyafa

      Garfinkel, Yosef; Streit, Katharina; Ganor, Saar; Hasel, Michael G. (Department of Geosciences, The University of Arizona, 2012-10-15)
      During the past 30 yr, the biblical narrative relating to the establishment of a kingdom in Judah has been much debated. Were David and Solomon historical rulers of an urbanized state-level society in the early 10th century BC, or was this level of social development reached only at the end of the 8th century BC, 300 yr later? Recent excavations at Khirbet Qeiyafa, the first early Judean city to be dated by radiocarbon, clearly indicate a well-planned, fortified city in Judah as early as the late 11th to early 10th centuries BC. This new data has far-reaching implications for archaeology, history, and biblical studies.
    • List of Laboratories

      McClure, Mark (Department of Geosciences, The University of Arizona, 2012-10-15)
    • Keeping the Sea Out: Early Medieval Structures at Ca’ Foscari University, Venice, Italy

      Meadows, John; Martinelli, Nicoletta; Pignatelli, Olivia; Cester, Rossella; Fozzati, Luigi; Kromer, Bernd (Department of Geosciences, The University of Arizona, 2012-10-15)
      In 2004, the courtyard of Ca’ Foscari University, Venice, was excavated in advance of building work, revealing an unbroken sequence of archaeological deposits. The earliest layers consisted of redeposited natural sediment, packed into wattle structures, a system of land reclamation first described by Cassiodorus in AD 537–8, and now known from several other sites in the city. The ground level was built up and extended several times with successive wattle structures, before the eventual construction of a stone waterfront. We have used Bayesian modeling of dendrochronological, radiocarbon, and stratigraphic dating evidence to obtain a precise chronology for the earliest phases of occupation, and to compare it to the chronology of land reclamation at similar sites elsewhere in Venice.
    • Isotopes, Plants, and Reservoir Effects: Case Study from the Caspian Steppe Bronze Age

      Shishlina, Natalia Ivanovna; Zazovskaya, E.; van der Plicht, J.; Sevastyanov, V. (Department of Geosciences, The University of Arizona, 2012-10-15)
      Bronze Age human and animal bone collagen from several steppe Bronze Age cultures (i.e. Early Catacomb, East and West Manych Catacomb, and Lola cultures) shows large variations in δ13C and δ15N values. In general, we observed that the older the sample, the lower the δ13C and δ15N values. We hypothesize that more positive values of δ13C and δ15N are caused by change in diet and a more arid climate. For ancient sheep during drier periods of the Early Catacomb, East and West Manych Catacomb, and Lola cultures, we observed 2 groups with different C and N isotopic compositions, reflecting consumption of different types of fodder. During periods of aridization, C4 and C3 plants with high δ15N values appeared in the vegetation, also influencing bone collagen values. Human bones show reservoir effects, caused by aquatic diet components. These effects can be quantified by paired dating of human bone and associated terrestrial samples. Reservoir corrections have revised chronologies for the region. Some paired dates do not reveal reservoir effects. This can be explained in 2 alternative ways. One is that the human diet did not include aquatic components; rather, the diet was based on C3 vegetation with high δ15N values (13–15‰), and flesh/milk of domesticated animals. An alternative explanation is that humans consumed food from freshwater resources without reservoir effects.
    • Identification, Extraction, and Preparation of Reliable Lime Samples for 14C Dating of Plasters and Mortars with the “Pure Lime Lumps” Technique

      Pesce, Giovanni L. A.; Ball, Richard J.; Quarta, Gianluca; Calcagnile, Lucio (Department of Geosciences, The University of Arizona, 2012-10-15)
      Radiocarbon dating was first applied to historic lime mortars during the 1960s. However, despite the relative simplicity of the technique in principle, a number of subsequent studies have highlighted important aspects that should be considered. One of the most significant of these challenges arises from sample contamination by carbonaceous substances such as incompletely burnt limestone and aggregates of fossil origin containing “dead” 14C. More recent studies have shown that in the majority of old lime-based mixtures the contamination problem can be avoided through selection of pure lime lumps. These particular types of lumps are believed to originate from areas where the lime is incompletely mixed with the aggregate. It has been demonstrated that even a single lime lump can provide sufficient material for a 14C date of the mortar from which the lump was taken (Pesce et al. 2009). This paper describes the practical challenges associated with location, extraction, and preparation of 4 lime lumps extracted from 2 new sites for 14C dating. These include distinguishing the lime lumps from other lumps present in the matrix and the removal of material surrounding the lime lump. The coherence of 14C dating with other archaeological information on the chronology of historic sites is highlighted through case studies.
    • Integrating Non-Destructive Ion Beam Analysis Methods and AMS Radiocarbon Dating for the Study of Ancient Bronze Statues

      Quarta, Gianluca; Calcagnile, Lucio; Vidale, Massimo (Department of Geosciences, The University of Arizona, 2012-10-15)
      Analytical methods based on particle accelerators are widely used in cultural heritage diagnostics and archaeological sciences from the absolute dating of organic materials by means of radiocarbon accelerator mass spectrometry (AMS) to the analysis of the elemental composition of a wide range of materials (metals, obsidians, pottery) via ion beam analysis (IBA) techniques. At CEDAD (Centre for Dating and Diagnostics), the accelerator facility of the University of Salento, AMS 14C dating and PIXE (particle-induced X-ray emission)-PIGE (particle-induced gamma-ray emission) compositional analysis in external beam mode are combined to study certain archaeological materials. We present a review of the combined application of these analytical methods in the study of casting cores of the Riace bronzes, 2 classical Greek statues of extraordinary importance for the history of art.
    • Hunter-Gatherer Pottery and Charred Residue Dating: New Results on Early Ceramics in the North Eurasian Forest Zone

      Hartz, Sönke; Kostyleva, Elena; Piezonka, Henny; Terberger, Thomas; Tsydenova, Natalya; Zhilin, Mikhail G. (Department of Geosciences, The University of Arizona, 2012-10-15)
      This article discusses 18 accelerator mass spectrometry (AMS) radiocarbon dates from the peat bog sites Sakhtysh 2a, Ozerki 5, and Ozerki 17 in the Upper Volga region. The aim is to contribute to a better understanding of the emergence and dispersal of early ceramic traditions in northern Eurasia and their connection to the Baltic. With 1 exception, all dates were obtained from charred residue adhering to the sherd. A possible reservoir effect was tested on 1 piece of pottery from Sakhtysh 2a by taking 1 sample from charred residue, and another sample from plant fiber remains. Although a reservoir effect was able to be ruled out in this particular case, 4 other dates from Sakhtysh 2a and Ozerki 5 seem too old on typological grounds and might have been affected by freshwater reservoir effects. Considering all other reliable dates, the Early Neolithic Upper Volga culture, and with it the adoption of ceramics, in the forest zone of European Russia started around 6000 cal BC.
    • On the Resolution of 14C Dating Anomalies: Case Studies from New World Archaeology

      Taylor, R. E.; Southon, John (Department of Geosciences, The University of Arizona, 2012-10-15)
      We submit that anomalies in radiocarbon data in archaeological studies should be viewed positively as a stimulus to undertake further targeted research. Additional analyses to resolve anomalies have the potential to provide important insights into heretofore unstudied or incompletely understood depositional or geochemical processes affecting 14C values, particularly in certain types of samples and samples from certain types of environments. We consider 2 major categories or sources of 14C dating anomalies that we posit are mostly responsible for the vast majority of problematic 14C results: anomalous sample contexts and anomalous sample composition. Two additional sources of 14C anomalies are much more rarely encountered. Six case studies taken from New World archaeological studies are briefly presented to provide examples of where questions concerning the validity of 14C measurements generated additional and ultimately more accurate understandings of temporal relationships. AMS-based 14C measurement technology has rendered detailed investigations of 14C anomalies routinely feasible.
    • 14C Marine Reservoir Variability in Herbivores and Deposit-Feeding Gastropods from an Open Coastline, Papua New Guinea

      Petchey, Fiona; Ulm, Sean; David, Bruno; McNiven, Ian J.; Asmussen, Brit; Tomkins, Helen; Richards, Thomas; Rowe, Cassandra; Leavesley, Matthew; Mandui, Herman; et al. (Department of Geosciences, The University of Arizona, 2012-10-15)
      Herbivorous and deposit-feeding gastropods are a major component of archaeological shell middens worldwide. They provide a wealth of information about subsistence, economy, environment, and climate, but are generally considered to be less than ideal for radiocarbon dating because they can ingest sediment while they graze, inadvertently consuming terrestrial carbon in the process. However, few studies of 14C activity in herbivores or deposit-feeding gastropods have been conducted into this diverse range of animals that inhabit many environmental niches. Here, we present results investigating 14C variability in shells belonging to the families Strombidae and Potamididae from the Bogi 1 archaeological site, Caution Bay, southern coastal Papua New Guinea (PNG). These shells make up 39.3% of the shell MNI [minimum number of individuals] in the excavation units studied and some of these species are the most common taxa of neighboring sites. It would therefore be advantageous to establish if there are any 14C offsets associated with such animals, and identify those that can give reliable calendar ages. Our methodology combines a high-resolution excavation protocol, selection of short-lived samples identified to species level, and a tri-isotope approach using 14C, δ13C, and δ18O to evaluate the source of variability in shells. Our results indicate that considerable variation exists between different species of Strombidae with some inhabiting muddier environments that act as sinks for limestone-derived sediments with depleted 14C content. The magnitude of variation is, however, overshadowed by that measured in the mudwhelk, Cerithidea largillierti, which has the largest spread in 14C of any shellfish studied so far at Caution Bay. This animal ingests sediment within the estuary that contains 14C derived from both enriched and depleted sources.
    • Preliminary Radiocarbon Analyses of Contemporaneous and Archaeological Wood from the Ansanto Valley (Southern Italy)

      Capano, Manuela; Marzaioli, Fabio; Passariello, Isabella; Pignatelli, Olivia; Martinelli, Nicoletta; Gigli, Stefania; Gennarelli, Ida; De Cesare, Nicola; Terrasi, Filippo (Department of Geosciences, The University of Arizona, 2012-10-15)
      The Ansanto Valley (southern Italy) is characterized by hydrothermal phenomena, with volcanic gas emissions arising from some vents. In the 1st millennium BC, a sanctuary dedicated to the goddess Mephitis was built but later destroyed by landslides in the valley. During archaeological excavations in the 1950s, many items were found including wooden artifacts, preserved thanks to the imbibition and subsequent mineralization of the wood tissues due to the gas emissions. Radiocarbon dating of these objects is underway at CIRCE (Centre for Isotopic Research on Cultural and Environmental Heritage), in Caserta, Italy. Unfortunately, 2 main problems arise in dating these materials. The first is possible fossil dilution caused by the CO2 emitted from the nearby volcanic vents, which could affect the trees of the valley and also the archaeological materials. In order to determine the magnitude of the fossil dilution in the area, 14C measurements were performed on contemporaneous wood cored from 2 oak trees growing near the vents. 14C values measured in these samples confirmed the presence of a strong fossil dilution in the Ansanto Valley. The second problem is the restoration that the objects underwent during the last century (mostly by using modern organic substances). To investigate suitable pretreatment procedures for removing the restoration materials from the archaeological findings, contemporaneous wood was also analyzed. The wood of trees from the Ansanto Valley and from a distant village (unaffected by the Ansanto fossil dilution) were submitted to the same restoration process applied to the archaeological artifacts, followed by an “artificial weathering” process.  Some archaeological materials were also tested for the removal of restoration materials. We subjected the artificially aged trees and the archaeological samples to different chemical processes. Here, we present the results of these processes. Almost all methods turned out to be suitable for the contemporaneous wood, while the results for the archaeological samples remain uncertain. For this reason, more tests are needed, concerning the “artificial weathering,” the restoration, and the chemical procedure for removing the consolidation materials.
    • Plaster Characterization at the PPNB Site of Yiftahel (Israel) Including the Use of 14C: Implications for Plaster Production, Preservation, and Dating

      Poduska, Kristin M.; Regev, Lior; Berna, Francesco; Mintz, Eugenia; Milevski, Ianir; Khalaily, Hamudi; Weiner, Steve; Boaretto, Elisabetta (Department of Geosciences, The University of Arizona, 2012-10-15)
      The Pre-Pottery Neolithic B (PPNB) site of Yiftahel, Israel, contains abundant plaster floors. We surveyed the states of preservation of the plasters using an infrared spectroscopic assay that characterizes the extent of disorder of the atoms in the calcite crystal lattice. We identified the 3 best-preserved plaster samples that had disorder signatures most similar to modern plaster. We then studied the surface layers, fine-grained matrices, and large aggregates of these samples using micromorphology, Fourier transform infrared (FTIR) microscopy, stable carbon and radiocarbon concentrations. Even though some of the plaster components have a geogenic appearance in micromorphology slides and in FTIR spectra, the 14C analyses show that all components were exposed to high temperatures and as a result were equilibrated with the 14C content of the atmosphere ~10,000 yr ago. This implies that the plasters at Yiftahel were produced entirely from heat-altered calcite. We also show that these plasters have undergone significant diagenesis. The plaster component with the most disordered atomic signature, and hence the most similar in this respect to modern plaster, did indeed produce a 14C date close to the expected age.
    • Plant Remains and AMS: Dating Climate Change in the Aeolian Islands (Northeastern Sicily) During the 2nd Millennium BC

      Caracuta, V.; Fiorentino, G.; Martinelli, M. C. (Department of Geosciences, The University of Arizona, 2012-10-15)
      Archaeological plant remains, used to establish a reliable chronology by radiocarbon dating, are used here to investigate trends in past rainfall intensity.  The stable carbon isotope ratio in botanic remains depends on environmental conditions during the plant’s life. By comparing the δ13C and 14C of selected plant specimens from 3 protohistoric sites in the Aeolian Archipelago, it is possible to identify short-term changes in the rainfall intensity during the 2nd millennium BC. The climate signals inferred from carbon isotope analyses are compared to pollen data for the region and are found to be consistent with changes in vegetal cover. Finally, the climate signals are integrated with the history of the Aeolian communities and the resilience of settlers is evaluated.
    • Radiocarbon Age for the Cultural Layer of the Neolithic-Bronze Age Settlement Pesochnoe-1 (Lake Nero, Russia)

      Alexandrovskiy, A. L.; Voronin, K. V.; Dolgikh, A. V.; Kovalukh, N. N.; Skripkin, V. V.; Glavatskaya, E. V. (Department of Geosciences, The University of Arizona, 2012-10-15)
      Organic matter in the cultural layer of the ancient settlement Pesochnoe-1 near Lake Nero (NE of Moscow) yields reliable radiocarbon dates. The reason for this is the high concentrations of calcium and phosphorus in the cultural layer, especially in calcined bones. Several cultural epochs are distinguished in the cultural layer consisting of more or less homogeneous habitation deposits colored with humic susbstances. Artifacts of the Ljalovo culture are found in the lower part of the cultural layer; above these, artifacts of the Volosovo culture are present, and the upper part of the cultural layer corresponds to the Textile Ceramics culture. The 14C dates for humic substances in the layers show a good chronological stratification and correspond to known ages of these cultural stages. The 14C dates for the Ljalovo cultural layer cover 5600–5100 BP (4430–3900 cal BC), and dates for the Volosovo cultural layer span 4400–4200 BP (3000–2840 cal BC). Most dates from the upper part of the cultural layer correspond to the chronological interval of the Textile Ceramics culture and range from 3700 to 3200 BP (2100–1460 cal BC). More precise 14C dates were obtained for humic substances from archaeological objects in the upper cultural layer (hearths, fillings of pottery vessels, etc.): 3900–3500 BP (2100–1800 cal BC).
    • 14C Dating of the Early Natufian at el-Wad Terrace, Mount Carmel, Israel: Methodology and Materials Characterization

      Eckmeier, Eileen; Yeshurun, Reuven; Weinstein-Evron, Mina; Mintz, Eugenia; Boaretto, Elisabetta (Department of Geosciences, The University of Arizona, 2012-10-15)
      The Natufian (15–11.5 kyr BP) sites in the southern Levant are characterized by a lack of macrobotanical remains, including charcoal, and poor preservation of bone collagen. As a result, only about 30 reliable radiocarbon dates are available for building a chronology of the Natufian period. Here, we present new 14C data from the Natufian site of el-Wad terrace that fall in the range of the Early Natufian period. Using Fourier transform infrared (FTIR) analysis, we investigated the environmental factors that influenced the preservation of material for 14C dating of the site, and we tested a modified pretreatment method for poorly preserved charcoal samples. The normal pretreatment protocol for 14C samples (W-ABA) removed more charcoal material than the modified method, which omits the first acid treatment (W-BA). This first acid step seems to enhance the extraction of humic substances during the subsequent base step. We found that the poor preservation of charcoal could be attributed to the presence of calcite, and therefore an alkaline pH of sediments. The most important factor determining bone collagen preservation may have been the hydrological setting, i.e. fluctuating water levels due to oversatu-ration of the dense sediments after rainfall.
    • 14C Dating of Fire-Damaged Mortars from Medieval Finland

      Lindroos, Alf; Regev, Lior; Oinonen, Markku; Ringbom, Åsa; Heinemeier, Jan (Department of Geosciences, The University of Arizona, 2012-10-15)
      This study focuses on radiocarbon dating of mortars that have withstood city fires and display visible fire damage effects. Some fire-damaged and undamaged original Medieval mortars from the same site have also been tested. The mortars were heated at different temperatures and then analyzed using the same preparation procedures as in 14C dating of mortars to see what kind of changes the heating would introduce to the mineralogy, chemistry, and the carbon and oxygen isotope ratios. We found that decarbonation during heating starts at ~600 °C and recarbonation starts as soon as the temperature drops. Already after a few days, most of the lost CO2 has been replaced with atmospheric CO2. The renewed carbonates are readily soluble in the acid hydrolysis process and their carbon and oxygen isotopes have a light signature. Fire-damaged historical mortars display the same features. If a long time has elapsed between hardening of the original mortar and the fire, the new carbonates have 14C concentrations that point to the fire event rather than to the building event. In several cases, the fire-damaged mortars have an easily soluble carbonate fraction with a 14C age that could be related to a major fire event, but still most of the soluble carbonate yields a 14C age that seems like a reasonable age for the original construction.
    • Preface from the Guest Editors

      Boaretto, Elisabetta; Rebollo Franco, Noemi (Department of Geosciences, The University of Arizona, 2012-10-15)