• Table of Contents

      Department of Geosciences, The University of Arizona, 2010-01-01
    • Table of Contents

      Department of Geosciences, The University of Arizona, 2010-01-01
    • Table of Contents

      Department of Geosciences, The University of Arizona, 2010-01-01
    • Table of Contents

      Department of Geosciences, The University of Arizona, 2010-01-01
    • Temporal and Spatial Variations in Freshwater 14C Reservoir Effects: Lake Mývatn, Northern Iceland

      Ascough, P. L.; Cook, G. T.; Church, M. J.; Dunbar, E.; Einarsson, Á.; McGovern, T. H.; Dugmore, A. J.; Perdikaris, S.; Hastie, H.; Friðoriksson, A.; et al. (Department of Geosciences, The University of Arizona, 2010-01-01)
      Lake Mvatn is an interior highland lake in northern Iceland that forms a unique ecosystem of international scientific importance and is surrounded by a landscape rich in archaeological and paleoenvironmental sites. A significant freshwater reservoir effect (FRE) has been identified in carbon from the lake at some Viking (about AD 870-1000) archaeological sites in the wider region (Mvatnssveit). Previous accelerator mass spectrometry (AMS) measurements indicated this FRE was about 1500-1900 14C yr. Here, we present the results of a study using stable isotope and 14C measurements to quantify the Mvatn FRE for both the Viking and modern periods. This work has identified a temporally variable FRE that is greatly in excess of previous assessments. New, paired samples of contemporaneous bone from terrestrial herbivores and omnivores (including humans) from Viking sites demonstrate at least some omnivore diets incorporated sufficient freshwater resources to result in a herbivore-omnivore age offset of up to 400 14C yr. Modern samples of benthic detritus, aquatic plants, zooplankton, invertebrates, and freshwater fish indicate an FRE in excess of 5000 14C yr in some species. Likely geothermal mechanisms for this large FRE are discussed, along with implications for both chronological reconstruction and integrated investigation of stable and radioactive isotopes.
    • The 4000-Year-Old "Longshan Giant" Discovered in Shaanxi Province, China

      Yang, Yachang; Zhu, Yizhi (Department of Geosciences, The University of Arizona, 2010-01-01)
      A human skeleton of phenomenal size was uncovered during the excavation of a prehistoric site located in the city of Shangnan, Shaanxi province, China, in 2006. The skeleton dates to 4240-4100 cal yr BP, corresponding to the Longshan culture (4400-4000 yr ago). The skeletal characteristics point to a young male 16-18 yr old with a height of 193 cm. This is the tallest skeleton ever discovered in prehistoric China, and thus we name him the "Longshan Giant." The giant appears to be of the Mongoloid race and has many physical characteristics that are similar to those of modern southern Asians. Upon closer examination, 3 drilled holes of 5 cm in diameter were found in the right parietal bone of the skull. No rationale exists yet to explain the presence of these holes.
    • The Application of ICELS Systems for Radiocarbon Dating

      Tudyka, Konrad; Pazdur, Anna; Theodórsson, Pall; Michczyński, Adam; Pawlyta, Jacek (Department of Geosciences, The University of Arizona, 2010-01-01)
      Liquid scintillation counting (LSC) for radiocarbon dating is a less expensive method than accelerator mass spectrometry (AMS), provides a high degree of accuracy, and is less prone to contamination due to the larger sample sizes. However, to obtain high precision, a long counting time is needed. The Gliwice Radiocarbon Laboratory is seeking to obtain an increased counting capacity with 2-3 mL benzene samples than we presently can achieve with our 2 Quantulus systems. We are therefore investigating the possibility of using a simple, single-phototube LS system (ICELS) for dating samples younger than 5000 yr. We present the first results of this investigation, including the measurement of 3 VIRI and 3 FIRI intercomparison samples.
    • The Artemidorus Papyrus: Solving an Ancient Puzzle with Radiocarbon and Ion Beam Analysis Measurements

      Fedi, M. E.; Carraresi, L.; Grassi, N.; Migliori, A.; Taccetti, F.; Terrasi, F.; Mandò, P. A. (Department of Geosciences, The University of Arizona, 2010-01-01)
      Ancient papyrus manuscripts are one of the most fascinating sources for reconstructing not only ancient life habits but also past literature. Recently, an amazing document has come to the fore due to the heated debates it raised: the so-called Artemidorus papyrus. It is a very long scroll (about 2.5 m) composed of several fragments of different sizes, with inscriptions and drawings on both sides. On the recto of the document, a text about geography and some drawings of heads, feet, and hands are present, while on the verso there are many sketches of animals, both real and fantastic. Its importance in classical studies comes from the fact that some scholars claim that it is the first known transcription of a relatively large fragment by the Greek geographer Artemidorus. However, other scholars think that the papyrus is a fake, drawn in the 19th century AD by a well-known forger. In order to overcome all possible ambiguities, the papyrus has been studied not only on the basis of historical and paleographic criteria but also by scientific techniques. We have contributed to the knowledge about the papyrus by radiocarbon dating the document and by analyzing the composition of the ink using ion beam analysis (IBA). Results are compatible with the scroll being an ancient manuscript: accelerator mass spectrometry (AMS) 14C measurements have dated the papyrus to a period between the 1st century BC and 1st century AD, while IBA measurements have pointed out the use of an organic (carbon-based) ink, which was typical of ancient Roman and Greek times. Details of the measurements are presented to emphasize the importance of combining AMS and IBA results.
    • The Carbon Origin of Structural Carbonate in Bone Apatite of Cremated Bones

      Van Strydonck, M.; Boudin, M.; Mulder, G. (Department of Geosciences, The University of Arizona, 2010-01-01)
      In order to reveal a possible carbon exchange between carbon dioxide of the fuel and the bone apatite during the cremation process an experiment was set up using fossil fuel. Two setups were constructed, one using natural gas and one using coal. In both experiments, a carbon substitution in the apatite was revealed.
    • The Chronology of Pleistocene Modern Humans in China, Korea, and Japan

      Keates, S. G. (Department of Geosciences, The University of Arizona, 2010-01-01)
      The chronological status of Pleistocene fossils of early modern humans in the People's Republic of China is based almost exclusively on indirect dating of the stratigraphic context and faunal and radiocarbon dating of associated or supposedly associated archaeological specimens. A similar pattern is observed in Korea and Japan. This paper examines the 14C and other dating techniques of early modern humans in East Asia to gain a more complete and up-to-date understanding of their chronology.
    • The Effect of Storage on the Radiocarbon, Stable Carbon and Nitrogen Isotopic Signatures and Concentrations of Riverine DOM

      Gulliver, P.; Waldron, S.; Scott, E. M.; Bryant, C. L. (Department of Geosciences, The University of Arizona, 2010-01-01)
      Chemical preservatives (e.g. mercuric chloride) are routinely added to freshwater samples to prevent biological activity compromising the isotopic signature of dissolved organic matter (DOM) with time. However, alternative preservation methods are needed due to regulations restricting the use of preservatives with potentially adverse environmental and health impacts, rendering such additions unviable. This study investigates whether a non-chemical storage method is sufficient to maintain the radiocarbon and stable carbon and nitrogen signatures of freshwater DOM from a low order river system draining a peaty catchment. Some 50 L of stream water were collected in 1 plastic carbuoy and, within 24 hr, 1-L aliquots were transferred to acid-washed plastic bottles. Five aliquots were analyzed immediately to determine the baseline values for 14C (pMC), 13C (VPDB), 15N (AIR), %C (mg L-1), and %N (mg L-1). Of the remaining subsamples, 20 were frozen and a further 20 refrigerated at 4 C. After 7, 30, 90, and 180 days, 5 frozen and 5 refrigerated aliquots were analyzed in the same manner as the baseline aliquots. Analysis of the results shows that there is no statistically significant interaction between the variables storage method or length of storage for any of the determinants. Storage method has a statistically significant effect on 14C (pMC) and [C] (mg L-1). Length of storage has a statistically significant effect on 13C (VPDB), [C] (mg L-1), and [N] (mg L-1) values. Neither storage method nor length of storage appear to have a statistically significant effect on 15N (AIR) values.
    • The Effects of Rainfall on Carbon Isotopes of POC in the Teshio River, Northern Japan

      Aramaki, T.; Nakamura, Y-H.; Uchida, M.; Shibata, Y. (Department of Geosciences, The University of Arizona, 2010-01-01)
      During a rainfall event in early September 2006, the transport behavior of particulate organic carbon (POC) in a small river (Teshio River, northern Japan) with alluvial plain and forest characteristics was investigated chiefly with carbon isotopes. The radiocarbon (∆14C value) of POC varied widely from -56 at the beginning of the rain event to -10 at peak rainfall. The ∆14C values have a positive correlation with C/N ratios and a negative correlation with 13C values except for the data from when both turbidity and water level were at their maximums due to rainfall. These results indicate that the sources of organic matter in the river come from the surface layer of soil as the water level rises during a rainfall event.
    • The Fifth International Radiocarbon Intercomparison (VIRI): An Assessment of Laboratory Performance in Stage 3

      Scott, E. Marian; Cook, Gordon T.; Naysmith, Philip (Department of Geosciences, The University of Arizona, 2010-01-01)
      Proficiency testing is a widely used, international procedure common within the analytical chemistry community. A proficiency trial (which VIRI is) often follows a standard protocol, including analysis that is typically based on zscores, with one key quantity, p. From a laboratory intercomparison (sometimes called a proficiency trial), we hope to gain an assessment of accuracy (in this case, from dendro-dated samples), laboratory precision (from any duplicate samples), and generally, an overall measure of performance, including measurement variability and hence realistic estimates of uncertainty. In addition, given our stated aim of creating an archive of reference materials, we also gain a determination of consensus values for new reference materials. VIRI samples have been chosen to deliver these objectives and the sample ages included in the different stages, by design, spanned modern to background. With regard to pretreatment, some samples required intensive pretreatment (e.g. bone), while others required none (e.g. cellulose and humic acid). Sample size was not optimized, and indeed some samples were provided solely for accelerator mass spectrometry (AMS) measurement. In this sense, VIRI presented a more challenging exercise than previous intercomparisons, since by its design in stages, one can explore improvements (or deteriorations) over time in laboratory performance. At each stage, more than 50 laboratories have participated, with an increasing demographic shift towards more AMS and fewer radiometric laboratories.
    • The Impact of Holocene Climate on the Development of Prehistoric Societies in Southern Siberia

      Kulkova, Marianna; Krasnienko, Sergey (Department of Geosciences, The University of Arizona, 2010-01-01)
      Geochemical data of 10Be, 14C, 18O obtained from natural archives (tree rings, ice sheets, varves, corals) indicates that the climate during the Holocene was not stable. The cosmogenic isotope fluctuations are bound by the periodicity on solar activity and climatic changes. The sharpest and most abrupt climatic deteriorations are registered in the Early and Middle Holocene at 8200, 5800, 5400, 4300, and 2800 cal BP. These events are characterized by cold conditions. The impact of climate on human communities in steppe depressions in southern Siberia (Nazarovo, Minusinsk, and Turano-Uyuk) was noticeable. The differences of local landscape-climatic conditions in these depressions were connected with global climatic changes to determine the processes of occupation, development, and migrations of ancient societies during the Neolithic, Bronze Age, and Iron Age. The chronology of archaeological cultures was also correlated with the local and global climatic changes during the Early and Middle Holocene in southern Siberia. Here, we generalize the literature data about Holocene climatic changes and archaeological cultures in the southern Siberia region.
    • The Influences of Hydrology on the Radiogenic and Stable Carbon Isotope Composition of Cave Drip Water, Grotta di Ernesto (Italy)

      Fohlmeister, J.; Schröder-Ritzrau, A.; Spötl, C.; Frisia, S.; Miorandi, R.; Kromer, B.; Mangini, A. (Department of Geosciences, The University of Arizona, 2010-01-01)
      14C and 13C values of C-containing species in cave drip waters are mainly controlled by the C isotope composition of karst rock and soil air, as well as by soil carbon dynamics, in particular the amount of soil CO2 in the unsaturated soil zone and the process of calcite dissolution. Here, we investigate soil carbon dynamics by analyzing the 14C activity and 13C values of C dissolved in cave drip water. Monthly over a 2-yr period, we collected drip water from 2 drip sites, one fast and one relatively slow, within the shallow Grotta di Ernesto Cave (NE Italy). The 14C data reveal a pronounced annual cycle. In contrast, the 13C values do not show an annual pattern and only small interannual variability compared to the 13C values of soil waters. The annual 14C drip-water cycle is a function of drip-rate variability, soil moisture, and ultimately hydrology.
    • The Iron I/IIA Transition in the Levant: A Reply to Mazar and Bronk Ramsey and a New Perspective

      Finkelstein, Israel; Piasetzky, Eli (Department of Geosciences, The University of Arizona, 2010-01-01)
      Mazar and Bronk Ramsey (2008) recently proposed that the Iron I/IIA transition in the Levant took place during the first half of the 10th century. In the first part of this article, we challenge their method and conclusions. We argue against the inclusion of charcoal in their model, which could lead to an 'old wood effect.' We also argue that in dealing with a transition date, all available data must be taken into consideration. In the second part of the article, we propose Bayesian Model I for the Iron I/IIA transition, which is based on 2 sets of data--for the periods immediately before and after this transition. Our model, along with the other 11 published Bayesian models for this transition that used only short-lived samples, agrees with the Low Chronology system for the Iron Age strata in the Levant and negates all other proposals, including Mazar's Modified Conventional Chronology. The Iron I/IIA transition occurred during the second half of the 10th century. In the third part of the article, we present a new insight on the Iron I/IIA transition. We propose that the late Iron I cities came to an end in a gradual process and interpret this proposal with Bayesian Model II. Mazar and Bronk Ramsey (2008) recently challenged Sharon et al. (2007; also Boaretto et al. 2005) and us (e.g. Finkelstein and Piasetzky 2003, 2007a,b) regarding the date of transition from the Iron I to the Iron IIA in the Levant. While we and Sharon et al. placed this transition in the second half of the 10th century BCE, Mazar and Bronk Ramsey positioned it 'during the first half of the 10th century BCE' and argued that 'the second half of the 10th century BCE should be included in the Iron IIA' (Mazar and Bronk Ramsey 2008:178). We discuss some problems in the methodology of Mazar and Bronk Ramsey that may have influenced their results. In particular, we discuss 1) the exclusion of data; 2) the inclusion of data (charcoal samples); and 3) show that even according to Mazar and Bronk Ramsey, excluding these samples position the late Iron I/IIA transition in the late 10th century. Finally, we present our own 2 Bayesian models for the Iron I/IIA transition.
    • The Keck Carbon Cycle AMS Laboratory, University of California, Irvine: Status Report

      Beverly, R. K.; Beaumont, W.; Tauz, D.; Ormsby, K. M.; von Reden, K. F.; Santos, G. M.; Southon, J. R. (Department of Geosciences, The University of Arizona, 2010-01-01)
      We present a status report of the accelerator mass spectrometry (AMS) facility at the University of California, Irvine, USA. Recent spectrometer upgrades and repairs are discussed. Modifications to preparation laboratory procedures designed to improve sample throughput efficiency while maintaining precision of 2-3 for 1-mg samples (Santos et al. 2007c) are presented.
    • The Late Paleolithic-Neolithic Transition in Korea: Current Archaeological and Radiocarbon Perspectives

      Bae, C. J.; Kim, J. C. (Department of Geosciences, The University of Arizona, 2010-01-01)
      The application of chronometric dating studies in Korean archaeology has lagged behind similar research in China and Japan. The focus of this article is to provide an update on the accelerator mass spectrometry (AMS) radiocarbon dates derived from Korean Paleolithic and Early Neolithic sites. One of the major highlights from recent AMS 14C studies in Korea is that blade (and microblade) technologies may have diffused directly from Siberia, rather than through northern China as originally thought. In addition, a Neolithic wooden boat has been discovered in Korea that is as old as, if not older than, similar discoveries from eastern China. More detailed archaeological and chronometric studies in Korea in the coming years will certainly clarify many of the points mentioned here. In particular, through more detailed studies, we will be able to further evaluate the causal factors that provided the impetus for the Late Paleolithic-Neolithic transition in Korea.
    • The Low-Energy Isobar Separator for Anions: Progress Report

      Kieser, W. E.; Eliades, J.; Litherland, A. E.; Zhao, X; Cousins, L.; Ye, S. J. (Department of Geosciences, The University of Arizona, 2010-01-01)
      The suppression of interferences from atomic and molecular isobars is a key requirement for the extension of accelerator mass spectrometry (AMS) to the analysis of new cosmogenic isotopes and for increasing the range of applications for small AMS systems. In earlier work, it was shown that unwanted isobars can be eliminated by anion-gas reactions (Litherland et al. 2007). Recently, a prototype system in which such reactions could be applied to ions from an AMS ion source, the Isobar Separator for Anions (ISA), was described (Eliades et al. 2009). This system decelerates the beam of rare anions from keV to eV energies, guides them through a single radiofrequency quadrupole (RFQ) gas cell, and re-accelerates them for further analysis in a 2.5MV AMS system. Tests of this system with Cl and S anions and NO2 gas showed a suppression of S with respect to Cl of over 6 orders of magnitude, with a transmission of ~30% for the Cl beam. In this work, results of the analysis of a range of standard reference materials are reported; these show the linearity of the system for measuring the 36Cl/35Cl ratio over a span of 2 orders of magnitude. Further tests, using the AMS system as a diagnostic tool, have provided clues about the loss of Cl at higher cell pressure and the nature of the residual low level of S transmission. These lead to the assessment of various gases for cooling the Cl- beam. Suppression measurements for 41K in the analysis of 41Ca, using NO2 as a reaction gas, are also discussed. These preliminary measurements have provided data for the development of a more advanced system with separate cooling and reaction cells.
    • The Origin of Pottery in East Asia and Its Relationship to Environmental Changes in the Late Glacial

      Kuzmin, Y. V. (Department of Geosciences, The University of Arizona, 2010-01-01)
      Mazar and Bronk Ramsey (2008) recently proposed that the Iron I/IIA transition in the Levant took place during the first half of the 10th century. In the first part of this article, we challenge their method and conclusions. We argue against the inclusion of charcoal in their model, which could lead to an 'old wood effect.' We also argue that in dealing with a transition date, all available data must be taken into consideration. In the second part of the article, we propose Bayesian Model I for the Iron I/IIA transition, which is based on 2 sets of data--for the periods immediately before and after this transition. Our model, along with the other 11 published Bayesian models for this transition that used only short-lived samples, agrees with the Low Chronology system for the Iron Age strata in the Levant and negates all other proposals, including Mazar's Modified Conventional Chronology. The Iron I/IIA transition occurred during the second half of the 10th century. In the third part of the article, we present a new insight on the Iron I/IIA transition. We propose that the late Iron I cities came to an end in a gradual process and interpret this proposal with Bayesian Model II. Mazar and Bronk Ramsey (2008) recently challenged Sharon et al. (2007; also Boaretto et al. 2005) and us (e.g. Finkelstein and Piasetzky 2003, 2007a,b) regarding the date of transition from the Iron I to the Iron IIA in the Levant. While we and Sharon et al. placed this transition in the second half of the 10th century BCE, Mazar and Bronk Ramsey positioned it 'during the first half of the 10th century BCE' and argued that 'the second half of the 10th century BCE should be included in the Iron IIA' (Mazar and Bronk Ramsey 2008:178). We discuss some problems in the methodology of Mazar and Bronk Ramsey that may have influenced their results. In particular, we discuss 1) the exclusion of data; 2) the inclusion of data (charcoal samples); and 3) show that even according to Mazar and Bronk Ramsey, excluding these samples position the late Iron I/IIA transition in the late 10th century. Finally, we present our own 2 Bayesian models for the Iron I/IIA transition.