• AMS Radiocarbon Dating of an Ancient Pottery Workshop in Hepu County, China

      Ruan, X.; Guan, Y.; Xiong, Z.; Wu, W.; Wang, H.; Jiang, S.; He, M.; Liu, K.; Terrassi, F.; Capano, M. (Department of Geosciences, The University of Arizona, 2010-01-01)
      An ancient pottery workshop belonging to the Han Dynasty was excavated in Caoxie village, Hepu County. Caoxie village is an important archaeological site in Hepu County, Beihai City, in south China's Guangxi Zhuang Autonomous Region. It is believed that Hepu County was the oldest departure point on the ancient maritime trading route during the Han Dynasty (206 BC to AD 220) due to the ideal natural geographical conditions and the existence of a large number of Han tombs. Radiocarbon measurements on wood and charcoal samples from the Caoxie village site were performed at the Peking University AMS facility (PKU-AMS), Beijing, and the Centre for Isotopic Research for Cultural and Environmental Heritage (CIRCE) at Naples Second University, Italy. Calibrated ages were obtained with code CALIB 5 (Stuiver and Reimer 1993). The results of these measurements are presented and the related chronology is discussed.
    • Towards On-Line 14C Analysis of Carbonaceous Aerosol Fractions

      Perron, N.; Szidat, S.; Fahrni, S.; Ruff, M.; Wacker, L.; Prévôt, A. H.; Baltensperger, U. (Department of Geosciences, The University of Arizona, 2010-01-01)
      Atmospheric carbonaceous aerosol is traditionally divided into organic carbon (OC) and elemental carbon (EC). Their respective carbon amounts are usually analyzed by means of an OC/EC analyzer and their fossil and non-fossil origins can be determined by radiocarbon analysis, which has proven to be a powerful tool for carbonaceous aerosol source apportionment. Thus far, separation of OC and EC has been performed off-line by manual and time-consuming techniques. We present an on-line system that couples a commercial OC/EC analyzer with the gas ion source of the accelerator mass spectrometer (AMS) MICADAS and its CO2 feeding system. The performance achieved with reference materials and blanks are discussed to demonstrate the potential of this coupling for source apportionment of atmospheric carbonaceous particulate matter.
    • Atmospheric Fossil Fuel CO2 Measurement Using a Field Unit in a Central European City during the Winter of 2008/09

      Molnár, M.; Haszpra, L.; Svingor, É.; Major, I.; Svetlik, I. (Department of Geosciences, The University of Arizona, 2010-01-01)
      A high-precision atmospheric CO2 monitoring station was developed as a field unit. Within this, an integrating CO2 sampling system was applied to collect samples for radiocarbon measurements. One sampler was installed in the second largest city of Hungary (Debrecen station) and 2 independent 14CO2 sampling lines were installed ~300 km from Debrecen in a rural site at Hegyhtsl station as independent background references, where high-precision atmospheric CO2 mixing ratios have been measured since 1994. Fossil fuel CO2 content in the air of the large Hungarian city of Debrecen was determined during the winter of 2008 using both the measurements of CO2 mixing ratio and 14C content of air. Fossil fuel CO2 was significantly enhanced at Debrecen relative to the clean-air site at Hegyhtsl.
    • Direct Absorption Method and Liquid Scintillation Counting for Radiocarbon Measurements in Organic Carbon from Sediments

      Faurescu, I.; Varlam, C.; Stefanescu, I.; Cuna, S.; Vagner, I.; Faurescu, D.; Bogdan, D. (Department of Geosciences, The University of Arizona, 2010-01-01)
      In this paper, we investigate a procedure for radiocarbon determination in forest soil and slurry from lake sediments. The total carbon in these samples can be both inorganic and organic. Inorganic carbon can be analyzed in a straightforward manner using the direct absorption method by sample acidification and CO2 capture. For organic carbon, we investigate a hybrid method using the wet-oxidation of organic carbon followed by direct absorption. To evaluate the wet-oxidation processes with potassium dichromate (K2Cr2O7) and potassium permanganate (KMnO4), we performed several experiments using different quantities of soil and sediments in order to establish the quantity of CO2 for each type of sample. The 2 methods offer comparable results for 14C-specific activity (about 0.234 0.024 Bq/g C), values that are expected for these kinds of samples. We also investigated the possibility of isotopic fractionation occurring during CO2 production from raw material by measuring 13C levels from samples and obtained CO2.
    • Early Bronze Age Strata at Tell Ghanem al-Ali along the Middle Euphrates in Syria: A Preliminary Report of 14C Dating Results

      Nakamura, T.; Hoshino, M.; Tanaka, T.; Yoshida, H.; Saito, T.; Tsukada, K.; Katsurada, Y.; Aoki, Y.; Ohta, T.; Hasegawa, A.; et al. (Department of Geosciences, The University of Arizona, 2010-01-01)
      We collected charcoal fragments during an archaeological excavation at the Tell Ghanem al-Ali site, located on the lowest terrace of the middle Euphrates River, and measured their radiocarbon ages with accelerator mass spectrometry (AMS). Two trenches, Square-1 and Square-2, were dug on the slope of the tell; 8 building levels were detected in the Square-2 trench. In total, 31 charcoal samples were collected from the 2 trenches, and their calibrated ages ranged from 3100-2900 cal BC at the lowest building level to 2400-2050 cal BC at the uppermost layers of the mound, and concentrated in the period 2650-2450 cal BC. The pottery fragments collected on the surface of the mound before the excavation survey was started, as well as those collected from the sediment layers during the excavation, were assigned on the basis of typological sequences to the Early Bronze Age (EB)-III and EB-IV periods. Thus, the concentrated dates (2650-2450 cal BC) obtained by 14C dating are consistent with the age estimated by archaeological contexts. However, the oldest dates of the lowest level (level-7) go back to 3100-2900 cal BC, and these dates may suggest the existence of the human residence prior to the EB period at the site, and may therefore lead to a revision of the oldest age limit of the EB period currently accepted in the region.
    • Dietary Reconstruction of the Okhotsk Culture of Hokkaido, Japan, Based on Nitrogen Composition of Amino Acids: Implications for Correction of 14C Marine Reservoir Effects on Human Bones

      Naito, Y. I.; Chikaraishi, Y.; Ohkouchi, N.; Mukai, H.; Shibata, Y.; Honch, N. V.; Dodo, Y.; Ishida, H.; Amano, T.; Ono, H.; et al. (Department of Geosciences, The University of Arizona, 2010-01-01)
      The relative contribution of marine-derived carbon in the ancient diet is essential for correcting the marine reservoir effect on the radiocarbon age of archaeological human remains. In this study, we evaluated the marine protein consumption of 3 human populations from the Okhotsk culture (about AD 550-1200) in Hokkaido, Japan, based on stable carbon and nitrogen isotopic compositions in bulk bone collagen as well as the nitrogen isotopic composition of glutamic acid and phenylalanine. Despite the similarity of carbon and nitrogen isotopic composition of bulk collagens, nitrogen isotopic composition of their constituent amino acids suggests differences in fur seal contributions among northern Hokkaido (0-24% for Kafukai 1, 0-10% for Hamanaka 2) and eastern Hokkaido (78-80% for Moyoro) populations. It suggests that nitrogen composition of glutamic acid and phenylalanine could provide a detailed picture of ancient human subsistence.
    • Dietary Habits and Freshwater Reservoir Effects in Bones from a Neolithic NE German Cemetery

      Olsen, J.; Heinemeier, J.; Lübke, H.; Lüth, F.; Terberger, T. (Department of Geosciences, The University of Arizona, 2010-01-01)
      Within a project on Stone Age sites of NE Germany, 26 burials from the Ostorf cemetery and some further Neolithic sites have been analyzed by more than 40 accelerator mass spectrometry (AMS) dates. We here present the results of stable isotope and radiocarbon measurements together with reference 14C dates on grave goods from terrestrial animals such as tooth pendants found in 10 of the graves. Age differences between human individuals and their associated grave goods are used to calculate 14C reservoir effects. The resulting substantial reservoir effects have revealed misleadingly high 14C ages of their remains, which originally indicated a surprisingly early occurrence of graves and long-term use of this Neolithic burial site. We demonstrate that in order to 14C date the human bones from Ostorf cemetery, it is of utmost importance to distinguish between terrestrial- and freshwater-influenced diet. The latter may result in significantly higher than marine reservoir ages with apparent 14C ages up to ~800 yr too old. The carbon and nitrogen isotopic composition may provide a basis for or an indicator of necessary corrections of dates on humans where no datable grave goods of terrestrial origin such as tooth pendants or tusks are available. Based on the associated age control animals, there is no evidence that the dated earliest burials occurred any earlier than 3300 BC, in contrast to the original first impression of the grave site (~3800 BC).
    • Dietary Reconstruction and Reservoir Correction of 14C Dates on Bones from Pagan and Early Christian Graves in Iceland

      Sveinbjörnsdóttir, Á. E.; Heinemeier, J.; Arneborg, J.; Lynnerup, N.; Ólafsson, G.; Zoëga, G. (Department of Geosciences, The University of Arizona, 2010-01-01)
      In this study, delta-13C and delta-15N of bone samples from 83 skeletons (79 humans, 2 horses, and 2 dogs) excavated from pagan and early Christian graves from 21 localities in Iceland are used to reconstruct diet of the early settlers in Iceland and possible differences in diet depending on the distance between the excavation site and the seashore. We have radiocarbon dated 47 of these skeletons and used the carbon isotopic composition (delta-13C) to estimate and correct for the marine reservoir effect (the 14C difference between terrestrial and mixed marine organisms). The reservoir-corrected ages lie in the range of AD 780-1270 (68.2% probability). Reservoir age corrections were checked by comparing 14C dates of a horse (terrestrial diet), a dog (highly marine diet), and a human (mixed diet) from the same burial. The range in measured marine protein percentage in individual diet is from about 10% up to 55%, mostly depending on the geographical position (distance from the sea) of the excavation site. We had access to the skeleton (AAR-5908) of the Skálholt bishop Páll Jónsson whose remains are enshrined at the Episcopal residence in Skálholt, southern Iceland. According to written sources, the bishop died in AD 1211. Using our dietary reconstruction, his bones were about 17% marine, which is within the range of human skeletons from the same area, and the reservoir-corrected calibrated 14C age of the skeleton is in accord with the historical date.
    • Editorial Board

      Department of Geosciences, The University of Arizona, 2010-01-01
    • Establishing a Firm Chronological Framework for Neolithic and Early Dynastic Archaeology in the Shangluo Area, Central China

      Zhu, Y.; Cheng, P.; Yu, S-Y.; Yu, H.; Kang, Z.; Yang, Y.; Jull, A. J. T.; Lange, T.; Zhou, W. (Department of Geosciences, The University of Arizona, 2010-01-01)
      Technological and theoretical advancements in modern radiocarbon chronology make the precise dating of archaeological and geological events possible. Here, we show examples of how these state-of-the-art methods can be used to establish and refine the archaeological cultural chronology for the Shangluo area in the Qinling Mountains of central China. In this study, the Donglongshan and Zijing sites were dated using the high-precision accelerator mass spectrometry (AMS) 14C method. Also, detailed magnetic-susceptibility measurements were conducted at both sites to gain preliminary information about past climate changes. The 14C dates, after being treated with Bayesian statistics, provide a firm constraint on the archaeological chronological framework for this area. Within this framework, the Malan loess-Holocene soil transition can be placed at 10,400-10,090 BC, while the duration of the Yangshao and Longshan cultures was dated to ~4200-2900 and ~2900-2100 BC, respectively, revealing an undisrupted history of human occupation in this area until the early dynastic period. Magnetic susceptibility values began to increase in the early Holocene, indicating a progressive amelioration of regional climate. The widespread development of paleosol during the middle Holocene indicates that warm and wet climate conditions prevailed, providing a favorable environmental context within which the Yangshao culture thrived. Magnetic susceptibility values then decreased from ~2100 BC when the Xia Dynasty started, and loess accumulated again, pointing to cooling and drying climate conditions that may have led to a cultural transition from the Neolithic to the dynastic civilization.
    • Estimation of Long-Term Trends in the Tropospheric 14CO2 Activity Concentration

      Svetlik, I.; Povinec, P. P.; Molnár, M.; Meinhardt, F.; Michálek, V.; Simon, J.; Svingor, É. (Department of Geosciences, The University of Arizona, 2010-01-01)
      Fossil CO2 emissions have been diluting the global 14C/C ratio of atmospheric CO2 (Suess effect). We estimated the 14CO2 amount in the atmosphere (and its trend) utilizing the calculated 14CO2 activity concentration in the atmosphere (aacn, reported in mBq m^(-3)). This parameter, calculated from ∆14CO2 and the CO2 mixing ratio (reported in micromoles of CO2 per mole of air), is connected with the 14CO2 quantity in the volume or mass unit of air, which is not influenced by the Suess effect. This parameter can only be influenced by processes linked to 14CO2 emissions/uptake, e.g. associated with atmosphere-biosphere or atmosphere-ocean CO2 exchange as well as by anthropogenic emissions of 14CO2. Results obtained from measurements at Schauinsland station, Germany, indicate a stable amount of 14CO2 in the atmosphere since the early 1990s.
    • Chronostratigraphic Sequence of Santuario della Madonna Cave (Calabria, Southern Italy): AMS Radiocarbon Data from a New Excavation Area

      Calcagnile, L.; Tinè, V.; Quarta, G.; D'Elia, M.; Fiorentino, G.; Scarciglia, F.; Robustelli, G.; Abate, M.; La Russa, M. F.; Pezzino, A. (Department of Geosciences, The University of Arizona, 2010-01-01)
      The Santuario della Madonna Cave, located near Praia a Mare (Cosenza), along the northwestern coast of Calabria (southern Italy), has an impressive stratigraphy, with occupation phases spanning from the late Paleolithic to the advanced phases of the Middle Bronze Age. Recently, a new excavation area has been opened in the cave from which short-lived vegetal remains were sampled and submitted for accelerator mass spectrometry (AMS) radiocarbon dating. The aim of this study was to define an accurate chronology of the different cultural aspects and to explore the potentialities resulting from application of advanced statistical tools for 14C data analysis in such a context.
    • Chronology of the Obi-Rakhmat Grotto (Uzbekistan): First Results on the Dating and Problems of the Paleolithic Key Site in Central Asia

      Krivoshapkin, A. I.; Kuzmin, Y. V.; Jull, A. J. T. (Department of Geosciences, The University of Arizona, 2010-01-01)
      The Obi-Rakhmat Grotto is one of the key Paleolithic sites in Central Asia. Archaeological excavations have revealed 22 strata containing archaeological materials. Lithic assemblages from all cultural layers display features similar to both late Middle Paleolithic blade industries and early Upper Paleolithic complexes in Southwest Asia and the Siberian Altai Mountains; this suggests a gradual Middle-to-Upper Paleolithic transition occurred in western Central Asia. Hominid remains found at Obi-Rakhmat (layer 16) show a mixture of archaic and modern traits. Different chronometric methods (radiocarbon, optically stimulated luminescence [OSL], U-series, and electron spin resonance [ESR]) were applied to the site's deposits. It appears that 14C dates are more reliable in terms of correspondence to the general framework of the Paleolithic of Central Asia and neighboring regions, and after critical analysis and the deletion of outliers, the upper part of the site's cultural sequence can be dated between 36,000-41,400 BP (layer 7) and ~48,800 BP (layer 14.1). The U-series dating results are less secure due to the high uranium content and the presence of detritus, which contaminates dated sediments (travertine). The OSL dating gave uniform ages for all cultural succession (~8 m of deposits), and confirms a very rapid sedimentation rate. Results of ESR dating depend greatly on the choice of uptake model. Dates calculated for the early uptake to some extent correspond to 14C data. The linear uptake chosen by Skinner et al. (2007) makes sediments very old (about 55,000-90,000 yr ago), which contradicts 14C dates and does not correspond well to the regional archaeological context.
    • 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.
    • Alternative Explanations for Anomalous 14C Ages on Human Skeletons Associated with the 612 BCE Destruction of Nineveh

      Taylor, R. E.; Beaumont, W. C.; Southon, J.; Stronach, D.; Pickworth, D. (Department of Geosciences, The University of Arizona, 2010-01-01)
      Three factors--contamination, a dietary reservoir effect, and a regional ∆14C anomaly--are considered as possible contributing explanations for an almost 2-century offset between the historically documented age of 612 BCE and the calibrated ages of 9 14C determinations obtained on 3 human skeletons directly associated stratigraphically with an archaeologically--and historically--defined 612 BCE event at the ancient site of Nineveh in northern Mesopotamia (Iraq). We note that on the order of a 1% (~80 yr) offset caused by one or a combination of these 3 factors, or other as yet unidentified additional factor(s), would be sufficient to move the average measured 14C age of these bone samples within the major "warp" in the 14C timescale during the mid-1st millennium BCE. We provide what we believe to be sufficient evidence that contamination is not a major factor in the case of these bone samples. At this time, we lack appropriate data to determine with sufficient rigor the degree to which a dietary reservoir effect may be contributing to the offset. At present, a posited regional ∆14C anomaly does not appear to be supported on the basis of data from several other localities in the Near East of similar age. One purpose of presenting this data set is to solicit comparisons with 14C values obtained on samples from additional, historically well-documented, known-age archaeological contexts for this time period in this and adjacent regions.
    • Environmental Changes of the Aral Sea (Central Asia) in the Holocene: Major Trends

      Krivonogov, S. K.; Kuzmin, Y. V.; Burr, G. S.; Gusskov, S. A.; Khazin, L. B.; Zhakov, E. Y.; Nurgizarinov, A. N.; Kurmanbaev, R. K.; Kenshinbay, T. I. (Department of Geosciences, The University of Arizona, 2010-01-01)
      Changes of the Aral Sea level have been observed in 3 sediment boreholes, 2 outcrops, and associated archaeological sites. The obtained results are supported by 25 radiocarbon dates. Major trends of lake-level changes have been reconstructed in some detail for the last 2000 yr, and additional data provide an outline of fluctuations throughout the Holocene. Several distinct changes are shown to precede the modern, human-induced regression of the Aral Sea. These include: 1) the latest maximum in the 16th-20th centuries AD (53 m asl); 2) a Medieval "Kerderi" minimum of the 12th-15th centuries AD (29 m asl); 3) the early Medieval maximum of the 4th-11th centuries AD (52 m asl); and 4) a near BC/AD lowstand, whose level is not well established. Since then, events are only inferred from sparse data. The studied cores contain several sandy layers representing the lowering of the lake level within the Holocene, including the buried shore-bar of ~4500 cal BP (38 m asl), and shallow-water sediments of ~5600 cal BP (44 m asl), 7200 cal BP (28 m asl), and 8000 cal BP (26.5 m asl).
    • Experimental Study on the Origin of Cremated Bone Apatite Carbon

      Hüls, C. M.; Erlenkeuser, H.; Nadeau, M.-J.; Grootes, P. M.; Andersen, N. (Department of Geosciences, The University of Arizona, 2010-01-01)
      Changes of the Aral Sea level have been observed in 3 sediment boreholes, 2 outcrops, and associated archaeological sites. The obtained results are supported by 25 radiocarbon dates. Major trends of lake-level changes have been reconstructed in some detail for the last 2000 yr, and additional data provide an outline of fluctuations throughout the Holocene. Several distinct changes are shown to precede the modern, human-induced regression of the Aral Sea. These include: 1) the latest maximum in the 16th-20th centuries AD (53 m asl); 2) a Medieval "Kerderi" minimum of the 12th-15th centuries AD (29 m asl); 3) the early Medieval maximum of the 4th-11th centuries AD (52 m asl); and 4) a near BC/AD lowstand, whose level is not well established. Since then, events are only inferred from sparse data. The studied cores contain several sandy layers representing the lowering of the lake level within the Holocene, including the buried shore-bar of ~4500 cal BP (38 m asl), and shallow-water sediments of ~5600 cal BP (44 m asl), 7200 cal BP (28 m asl), and 8000 cal BP (26.5 m asl).
    • Fish Reservoir Effect on Charred Food Residue 14C Dates: Are Stable Isotope Analyses the Solution?

      Boudin, M.; Van Strydonck, M.; Crombé, P.; De Clercq, W.; van Dierendonck, R. M.; Jongepier, H.; Ervynck, A.; Lentacker, A. (Department of Geosciences, The University of Arizona, 2010-01-01)
      In order to verify the relative dating based on pot type morphology and decoration of the Swifterbant pottery collected at the Final Mesolithic site of Doel "Deurganckdok" (Belgium) and of the Late Iron Age pottery excavated at Grijpskerke (the Netherlands), direct radiocarbon dates were obtained on charred food residue preserved on the inner surface of numerous potsherds. In addition, a number of indirect 14C dates were obtained from samples of organic material. In the case of Doel, the results indicate an important incompatibility between the charred food residue dates and the other dates, the former being systematically older. This difference may be explained by a reservoir effect of the charred food residue, caused by the processing of (freshwater) fish. The 14C dates for the rijpskerke site are in agreement between the charred food residue and the organic material. The stable isotopes of the charred food residue were analyzed to demonstrate fish processing in the pottery, but the results were inconclusive.
    • Fire History of a Giant African Baobab Evinced by Radiocarbon Dating

      Patrut, A.; Mayne, D. H.; Von Reden, Karl F.; Lowy, Daniel A.; van Pelt, Robert; McNichol, Ann P.; Roberts, Mark L.; Margineanu, D. (Department of Geosciences, The University of Arizona, 2010-01-01)
      The article reports the first radiocarbon dating of a live African baobab (Adansonia digitata L.), by investigating wood samples collected from 2 inner cavities of the very large 2-stemmed Platland tree of South Africa. Some 16 segments extracted from determined positions of the samples, which correspond to a depth of up to 15-20 cm in the wood, were processed and analyzed by accelerator mass spectrometry (AMS). Calibrated ages of segments are not correlated with their positions in the stems of the tree. Dating results indicate that the segments originate from new growth layers, with a thickness of several centimeters, which cover the original old wood. Four new growth layers were dated before the reference year AD 1950 and 2 layers were dated post-AD 1950, in the post-bomb period. Formation of these layers was triggered by major damage inside the cavities. Fire episodes are the only possible explanation for such successive major wounds over large areas or over the entire area of the inner cavities of the Platland tree, able to trigger regrowth.
    • Laser-Heated Microfurnace: Gas Analysis and Graphite Morphology

      Smith, A. M.; Yang, B.; Hua, Q.; Mann, M. (Department of Geosciences, The University of Arizona, 2010-01-01)
      We describe progress in developing a novel miniaturized laser-heated 'microfurnace' aimed at preparing ultra-small (~5 g) graphite samples from CO2 (Smith et al. 2006, 2007, 2010). Recent effort has focused on automation of the process using a LabVIEW interface, which has permitted feedback control of the catalyst temperature as the reaction proceeds and the logging of reaction parameters. We trialed a number of different pure iron catalysts as well as Fe2O3 (which is reduced in situ to iron) and discuss the reaction rates. We studied the graphite morphology by scanning electron microscopy (SEM) and found there is a marked difference in graphite morphology with catalyst type. We assessed how each catalyst performs in the cesium sputter ion source of the ANTARES Accelerator Mass Spectrometry (AMS) facility. We utilized a quadrupole mass spectrometer to study the gas composition during the reaction, in order to better understand the underlying chemical reactions for such small samples and to better estimate the overall efficiency of the process. Results show that all CO2 is converted to CO by reduction on the iron catalyst within a few minutes of applying laser power. The reaction pressure stabilizes after 40 min; however, some CO is not converted to graphite. The cold trap temperature of -80 C is effective at trapping H2O, so there is little CH4 production.