• 14C Chronology of Mesolithic Sites from Poland and the Background of Environmental Changes

      Pazdur, Anna; Fogtman, Mariusz; Michczyński, Adam; Pawlyta, Jacek; Zając, Mirosław (Department of Geosciences, The University of Arizona, 2004-01-01)
      Mesolithic sites in modern Poland are mainly located in the southern part of the country. Radiocarbon dating of organic material, such as charcoals, wood, and peat, provide a time frame of human settlements in those regions, and dating of speleothems and peat formations provide information on climatic conditions and the timing of climatic change in the region. Here, we present the results of calibrated 14C ages from 3 main Mesolithic sites: Glanów, Chwalim, and Calowanie. Summary probability density distributions of the calendar ages were obtained, and time ranges were ascribed to the cultures in conjunction with archaeological information. These distributions also reveal the changes in human settlement.
    • 14C Concentrations of Single-Year Tree Rings from About 22,000 Years Ago Obtained Using a Highly Accurate Measuring Method

      Kato, Katoh Wataru; Takahash, Takahashi Yousuke; Gunj, Gunji Syuichi; Tokana, Tokanai Fuyuki; Matsuzak, Matsuzaki Hiroyuki (Department of Geosciences, The University of Arizona, 2004-01-01)
      We have measured the radiocarbon concentrations in single-yr tree rings of old wood by accelerated mass spectrometry (AMS) using a multicathode. The 14C concentrations of 10 single-yr tree rings were measured in 100 tree rings at intervals of 10. For each single-yr tree-ring sample, typically 80 measurements of the 14C concentrations were carried out using multicathodes. The sample standard deviations indicated that there are other fluctuations of typically 1.5%, in addition to the fluctuation of the Poisson counting statistics, which is typically 3% for each measurement. The average 14C date of the tree rings was 22,130 +/306 BP for all 624 data of single-yr tree-ring samples measured by the multicathodes. From the calibration data of Lake Suigetsu, the calendar dates of these 100 tree rings were located between 25,400 cal BP and 26,150 cal BP. The 14C dates changed between 21,979 BP and 22,272 BP, with an error of approximately 50 BP, corresponding to a precision of approximately 0.5%. There was a step with a change of approximately 144 BP for each 10 yr in the time profile.
    • 14C Sources and Distribution in the Vicinity of La Hague Nuclear Reprocessing Plant: Part II—Marine Environment

      Maro, D.; Fontugne, M.; Hatté, C.; Hebert, D.; Rozet, M. (Department of Geosciences, The University of Arizona, 2004-01-01)
      Carbon dioxide partial pressure and radiocarbon activity were measured in air and seawater in the Bay of Seine and around the COGEMA-La Hague nuclear reprocessing plant (northwest France) during 3 cruises in 2000 and 2002. Results clearly show that the sea is a source of CO2 and 14C to the atmosphere. High 14C concentrations in air and water related to the La Hague liquid waste are clearly recorded. For the restricted area of the Bay of Seine, CO2 carbon and 14C fluxes were estimated, indicating that less than 3% of the liquid 14C release is introduced in the atmosphere.
    • 14C Sources and Distribution in the Vicinity of La Hague Nuclear Reprocessing Plant: Part I—Terrestrial Environment

      Fontugne, M.; Maro, D.; Baron, Y.; Hatté, C.; Hebert, D.; Douville, E. (Department of Geosciences, The University of Arizona, 2004-01-01)
      COGEMA-La Hague nuclear reprocessing plant in the Cotentin Peninsula (northwest France) releases in the atmosphere about 19 TBq.yr-1 of radiocarbon. Three experiments in a terrestrial environment with sampling of a bio-indicator like furze were performed in 1997, 1998, and 1999, and additional air samples in the chimney plume were measured. Results presented here establish the 14C distribution in the La Hague environment and suggest that a part of the 14C content in the vegetation near the coast results from a 14CO2 degassing of seawater supplied with the liquid waste from the nuclear plant.
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      Department of Geosciences, The University of Arizona, 2004-01-01
    • A 14C Calibration with AMS from 3500 to 3000 BC, Derived from a New High-Elevation Stone-Pine Tree-Ring Chronology

      Dellinger, Franz; Kutschera, Walter; Nicolussi, Kurt; Schießling, Peter; Steier, Peter; Wild, Eva Maria (Department of Geosciences, The University of Arizona, 2004-01-01)
      High-precision radiocarbon accelerator mass spectrometry (AMS) measurements of a new high-altitude stone-pine tree-ring chronology from the European Alps were performed for a 500-yr stretch in the second half of the 4th millennium BC. A 14C calibration curve with a typical 1-sigma uncertainty of about 20 14C yr was achieved. Although the general agreement of our data set with INTCAL98 is very good (confirming once more that INTCAL98 is also proper for calibration of samples of extraordinary sites), we found small deviations of 17 +/5 14C yr, indicating possible seasonal effects of the delayed growing season at high altitude.
    • A Direct Estimate of the Initial Concentration of 14C in the Mountain Aquifer of Israel

      Carmi, Israel; Kronfeld, Joel; Yechieli, Yoseph; Boaretto, Elisabetta; Bar-Matthews, Miryam; Ayalon, Avner (Department of Geosciences, The University of Arizona, 2004-01-01)
      Five radiocarbon analyses were performed on 5 different sources within Soreq Cave, which was used as a model for the Judea Group Aquifer of Israel (pMCq0). The transit time of rainwater through the roof of the cave to sources within it had been determined with tritium. From this information, the year of deposition of rain on the roof of the cave, which later appeared in one of the sources, was estimated and the atmospheric 14C concentration at that time was ascertained (pMCa0). The parameter Q = pMCq0 / pMCa0 was found to be Q = 0.60 +/0.04. This makes it possible to calculate the age of water in any well in the Judea Group Aquifer of Israel by measuring its 14C concentration (pMCqt) by use of the decay equation and applying Q.
    • An AMS 14C Pollen-Dated Sediment and Pollen Sequence from the Late Holocene, Southern Coastal Hawke's Bay, New Zealand

      Chester, Pamela I.; Prior, Christine A. (Department of Geosciences, The University of Arizona, 2004-01-01)
      Hawke's Bay is a region of New Zealand where earliest settlement of indigenous people may have occurred. A sedimentological and palynological study of lake sediments from a small catchment was undertaken to reconstruct erosion, vegetation, and fire histories to determine human environmental impact, and thus add to knowledge of the timing of initial settlement of New Zealand. Precise dating was an essential facet of the research because of the short time span of human occupation in New Zealand. A chronology is proposed based on accelerator mass spectrometry (AMS) radiocarbon dating of palynomorph concentrates. Known-age tephras were used as a check on the validity of the 14C ages obtained using this technique, which is being developed at Rafter Radiocarbon Laboratory. Two episodes of sustained erosion occurred between about 1500 and 1050 BC with a period of approximately 50 yr at about 1300 BC when no erosion occurred. Five episodes of erosion of very short duration occurred at about 625 BC, 450 BC, 100 BC, AD 950, and AD 1400. Erosion probably resulted from landslides induced by earthquakes or severe storms, with the exception of the last event which coincides with local burning and is probably a consequence of this. A conifer/broadleaved forest surrounded the lake until soon after AD 1075-1300, when a dramatic decline in pollen of forest plants and an increase in charcoal occurred. Forest was replaced by fire-induced scrub, interpreted as a result of anthropogenic burning by prehistoric Polynesians. A further decline in woody vegetation occurred when European-introduced plants appear in the pollen record and extensive pasture was established.
    • Bayesian Periodic Signal Detection Applied to INTCAL98 Data

      Palonen, V.; Tikkanen, P. (Department of Geosciences, The University of Arizona, 2004-01-01)
      A Bayesian multiple-frequency model has been developed for spectral analysis of data with unknown correlated noise. A description of the model is given and the method is applied to decadal atmospheric INTCAL98 Delta-14C data. The noise of the INTCAL98 data is found to be red, and there seems to be no support for continuous harmonic frequencies in the data.
    • Carbon Isotopic Composition of Tree Rings as a Tool for Biomonitoring CO2 Level

      Pawełczyk, Sławomira; Pazdur, Anna (Department of Geosciences, The University of Arizona, 2004-01-01)
      Carbon isotopes are widely used as indicators in the study of atmospheric CO2 variability in space and time. Preliminary results are part of a project investigating 13C and 14C concentration changes during the last 150 yr in Poland, both in industrial and ecologically clean regions, using annual tree rings (Pinus sylvestris, Populus nigra). The results describe the local Suess effect recorded in the industrial Krakow and Upper Silesia regions compared to changes of background radiocarbon concentration caused by global human activity in a "clean region", Augustów Wilderness. The delta-13C record also shows the influence of the local Suess effect.
    • Changes in Sediment Accumulation Rate in an Oxbow Lake Following Late 19th Century Clearing of Land for Agricultural Use: A 210Pb, 137Cs, and 14C Study in Mississippi, USA

      Davidson, Gregg R.; Carnley, Meredith; Lange, Todd; Galicki, Stanley J.; Douglas, Andrew (Department of Geosciences, The University of Arizona, 2004-01-01)
      Sediment cores were collected from 2 sites in the forested fringe of an oxbow lake surrounded by land that was converted from forest to agricultural use in the late 19th century. The 2 sampling areas were selected to represent areas of high (West site) and low (east site) current sediment accumulation rates, based on distance from a perennially discharging stream. Modern (post settlement and land clearing) sediment accumulation rates were calculated using 210Pb and 137Cs on bulk sediment samples from 2 cores from each site. Two additional cores were collected from each site for radiocarbon analysis of twig cellulose with the assumption that most twigs in the sediment within the forested fringe fell from overhead and are contemporaneous with the sediment. Only the West site, however, yielded sufficient identifiable twig material for analysis. Modern sediment accumulation rates based on 210P and 137Cs fall between 0.2-0.4 cm/yr at the East site, and 0.7-1.3 cm/yr at the West site (nearest the stream inlet), with approximate agreement between the 210Pb and 137Cs methods. Modern sediment accumulation rate based on bomb-pulse 14C activity of twigs from cores from the West site is approximately 1.0 cm/yr, in agreement with the 210Pb and 137Cs results results. Historic sediment accumulation rates were estimated at the West site using twigs from deeper intervals with pre-bomb 14C activity. Sediment covering approximately 1000 yr of pre-settlement sediment accumulation exhibited evidence of minor bioturbation or in-washing of reworked material, but with a clearly lower accumulation rate of less than 0.1 cm/yr.
    • Differentiating Bone Osteonal Turnover Rates by Density Fractionation; Validation Using the Bomb 14C Atmospheric Pulse

      Shin, Ji Young; O'Connell, Tamsin; Black, Stuart; Hedges, Robert (Department of Geosciences, The University of Arizona, 2004-01-01)
      The density (BSG) of bone increases, at the osteon scale, during lifetime aging within the bone. In addition, post-mortem diagenetic change due to microbial attack produces denser bioapatite. Thus, fractionation of finely powdered bone on the basis of density should not only enable younger and older populations of osteons to be separated but also make it possible to separate out a less diagenetically altered component. We show that the density fractionation method can be used as a tool to investigate the isotopic history within an individual's lifetime, both in recent and archaeological contexts, and we use the bomb 14C atmospheric pulse for validating the method.
    • Holocene Environmental Changes in Western Hungary

      Szántó, Zsuzsanna; Medzihradszky, Zsófia (Department of Geosciences, The University of Arizona, 2004-01-01)
      We review the reasons for change in paleoecological conditions and their effects on different cultures at the beginning and during the Holocene period in western Hungary using radiocarbon data combined with paleoecological and paleolimnological results. Two sites were investigated in the southern and northern part of the ancient bay of Balaton Lake: Keszthely-Úsztatómajor and Fónyed I. 14C dating of 2 core samples represented a chronology from 11,000 cal BC to 2000 cal BC (10,700 BP to 3700 BP) and from 6200 cal BC to 1200 cal BC (7300 BP to 3000 BP), respectively. A relatively constant inverse sediment accumulation rate was observed in both cases (23 yr/cm and 33 yr/cm, respectively). In the case of Fonyed I, a sharp break was observed in the sedimentation curve around 6000-4800 cal BC (6000 BP). Changes in the vegetation due to human activity were observed in a larger extent only at the end of Late Neolithic, with the most significant changes detected in the landscape coinciding with the presence of Lengyel III culture in the region. The appearance of higher amounts of pollen of cereals at the sites proved the presence of crop cultivation. However, the role of plant cultivation may have been limited for the ancient inhabitants of the Kis-Balaton region due to a limited amount of soil suitable for agriculture and due to the extensive water table. Further changes in vegetation were observed during the Late Copper Age (Baden culture) and the period of Early and Middle Bronze Age, respectively. Signs of forest clearing during the period have not been detected and the increased peak of Fagus indicates climatic change. The low intensity of anthropogenic activity should not be attributed to geographic isolation.
    • Holocene Evolution of the Outer Lake of Hwajinpo Lagoon on the Eastern Coast of Korea; Environmental Changes with Holocene Sea-Level Fluctuation of the East Sea (Sea of Japan)

      Yum, Jong-Gwon; Yu, Kang-Min; Takemura, Keiji; Naruse, Toshiro; Kitamura, Akihisa; Kitagawa, Hiroyuki; Kim, Jong-Chan (Department of Geosciences, The University of Arizona, 2004-01-01)
      The evolution of the outer lake of Hwajinpo Lagoon in Korea has been reconstructed using environmental proxies (lithologic, geochemical, and fossil data) with a chronology established using 7 accelerator mass spectrometry (AMS) radiocarbon dates. Grain size, water content, and X-ray analyses from the core of outer coastal lakes (HJ99) were used to reconstruct sedimentary environments by using total organic carbon, C/N, S, and C/S chemical proxies. Assemblages of mollusc remains also provided paleoenvironmental information. The environmental changes of the outer lake of Hwajinpo Lagoon can be divided into 6 depositional phases. The basin of the Hwajinpo was exposed and underwent a weathering process before the Holocene period. The muddy sand layer on the weathered bedrock indicated an estuarine system about 6000 BP. The laminated layer implies that the lagoonal system was anoxic between about 5500-2800 BP. The marl layer implies a relatively oxic lagoonal condition with mollusc presence about 2500 BP. The layer of very low sulfur content indicates a freshwater lake system isolated by a sand barrier about 1700 BP. Beginning about 1000 BP, the river system deposits progress progradation on the marl layer. Two erosional landforms could be related with a high standing sea level span during Holocene. These high-stands are dated at 5700 BP and 2200 BP and are supposed to have formed erosional landforms of about 1.6 amsl and 0.8 amsl, respectively. Environmental changes of the outer lake of Hwajinpo Lagoon are considered due mainly to the lake-and sea-level fluctuation during Holocene.
    • Holocene Variations in the Scottish Marine Radiocarbon Reservoir Effect

      Ascough, Philippa L.; Cook, Gordon T.; Dugmore, Andrew J.; Barber, John; Higney, Elaine; Scott, E. Marian (Department of Geosciences, The University of Arizona, 2004-01-01)
      We assessed the evidence for variations in the marine radiocarbon reservoir effect (MRE) at coastal, archaeological Iron Age sites in north and west Scotland by comparing AMS measurements of paired marine and terrestrial materials (4 pairs per context). Delta-R values were calculated from measurements on material from 3 sites using 6 sets of samples, all of which were deposited around 2000 BP. The weighted mean of the Delta-R determinations was -79 +/17 14C yr, which indicates a consistent, reduced offset between atmospheric and surface ocean 14C specific activity for these sites during this period, relative to the present day (Delta-R = ~0 14C yr). We discuss the significance of this revised Delta-R correction by using the example of wheelhouse chronologies at Hornish Point and their development in relation to brochs. In addition, we assess the importance of using the concepts of MRE correction and Delta-R variations when constructing chronologies using 14C measurements made on materials that contain marine-derived carbon.
    • Influence of 14C Concentration Changes in the Past on Statistical Inference of Time Intervals

      Michczyński, Adam (Department of Geosciences, The University of Arizona, 2004-01-01)
      The influence of the calibration curve on the statistical inference of time intervals was investigated. For this purpose, the calculation of the summed probability density function was used. Computer simulations were done for batches of 11 samples, each time uniformly covering 200-yr time intervals. The results show that the calibration curve causes the summed probability density function of a group to cover a wider interval than the real-time interval of the phenomenon. Moreover, the estimated time interval may be often shifted in relation to the real-time interval.
    • Interannual 14C Variations During 1977–1998 Recorded in Coral from Daya Bay, South China Sea

      Shen, C. D.; Yi, W. X.; Yu, K. F.; Sun, Y. M.; Yang, Y.; Zhou, B. (Department of Geosciences, The University of Arizona, 2004-01-01)
      Twenty-two annually banded samples of coral from 1977 to 1998 were collected from Daya Bay, South China Sea, and bomb 14C concentrations were determined. The interannual variation of coral ∆14C is controlled mainly by oceanic factors. In ENSO years, the coastwise upwelling current of the South China Sea has been intensified; hence, the coral ∆14C displays its minimum value. The interannual variation curve of ∆14C in coral bears a relationship with the Southern Oscillation Index (SOI) curves: the correlation coefficient between ∆14C and (SOI)w is 0.43 and the correlation coefficient between ∆14C and (SOI)y is 0.27. The coral ∆14C has no remarkable response to the variation of solar radiation energy. In the past 20 yr or so, the general situation and oceanic thermal structure of the South China Sea are still stable even though interannual variations in atmosphere-sea interaction and upwelling current driven by the tropical energy have occurred.
    • Interpreting Radiocarbon Dates Using Evidence from Tree Rings

      Bayliss, Alex; Tyers, Ian (Department of Geosciences, The University of Arizona, 2004-01-01)
      Often it is not possible to date a sample of wood from the final growth ring of the tree from which it came. In these cases, an "old-wood offset" is apparent. A number of quantitative approaches for the assessment of this offset are available, dependent on the actual tree rings that have been dated. A range of examples are given, demonstrating how such radiocarbon measurements can be interpreted using additional information from archaeology and dendrochronology.
    • Late Holocene Environmental Reconstruction of St. Michiel Saline Lagoon, Curacao (Dutch Antilles)

      Klosowska, Bogumila B.; Troelstra, Simon R.; van Hinte, Jan E.; Beets, Dirk; van der Borg, Klaas (Department of Geosciences, The University of Arizona, 2004-01-01)
      Two sediment cores collected from the saline lagoon St. Michiel on Curaçao (Dutch Antilles) preserve a approximately 5000-yr record of environmental change. Investigation of radiocarbon-dated sections by accelerator mass spectrometry (AMS) is based on faunal assemblage analyses, sediment mineralogy, and the interpretation of sedimentary facies. The cores recovered from different parts of the lagoon demonstrate different development. Initially, in the proximal part of the lagoon (core STM-2), the sediment accumulated in a coastal, semi-protected bay with strong marine influence, whereas the distal part (STM-1) was dominated by chemical precipitation (gypsum, aragonite). By about 3500-3400 BP, connection with the open sea became very limited due to the gradual formation of a coral rubble barrier at the coastline. Subsequently, the record reveals undisturbed sedimentation in the highly restricted shallow lagoon. Around 1100-1000 BP, biological and sedimentological records indicate a change to less evaporitic conditions. Stages of increased salinity are intercalated with intervals of episodic freshening due to increased runoff and precipitation. The authors demonstrate that since permanent human settlements were established on the island about 1100 BP, the watershed has undergone intensive deforestation, especially during the European colonization at the beginning of the 16th century. Deforestation resulting from agriculture and construction caused increased erosion, which was translated to increased sediment accumulation rates and a shift in lagoon sedimentation from almost entirely endogenic to mostly detrital.
    • Levels of 14C in the Terrestrial Environment in the Vicinity of Two European Nuclear Power Plants

      Magnusson, Åsa; Stenström, Kristina; Skorg, Göran; Adliene, Diana; Adlys, Gediminas; Hellborg, Ragnar; Olariu, Agata; Zakaria, Mohamad; Rääf, Christopher; Mattsson, Sören (Department of Geosciences, The University of Arizona, 2004-01-01)
      Radiocarbon is produced in all types of nuclear reactors. Most of the 14C released into the environment is in the form of gaseous emissions. Recent data on the 14C concentration found in terrestrial samples taken in the vicinity of nuclear power plants in Romania and Lithuania are presented. We found increased 14C levels in the surroundings of both power plants. At the Romanian power plant Cernavoda, we found excess levels of 14C in grass within a distance of about 1000 m, the highest 14C specific activity being 311 Bq/kg C (approximately 28% above the contemporary 14C background) found at a distance of 200 m from the point of release (nearest sampling location). At the Lithuanian power plant Ignalina, samples of willow, pine, and spruce showed a 14C excess of similar magnitude, while significantly higher values were found in moss samples. The samples were analyzed at the accelerator mass spectrometry facility in Lund, Sweden.