• 14C Ages of Tephra Layers from the Holocene Deposits of Kunashir Island (Russian Far East)

      Razjigaeva, N. G.; Grebennikova, T. A.; Ganzey, L. A.; Bazarova, V. B.; Mokhova, L. M.; Korotky, A. M.; Sulerzhitsky, L. D. (Department of Geosciences, The University of Arizona, 1998-01-01)
      Holocene deposits from the central and southern regions of the Kunashir Island contain tephra from 12 volcanic eruptions (Kn1-12). We studied radiocarbon data, mineralogical composition, and distribution of the tephra layers in different Holocene facies. The main sources of the Holocene tephra samples were the volcanoes of Hokkaido Island. The distribution of ash layers on Kunashir Island allows us to estimate their direction. Ash layers can be reliable markers for age determination of different coastal landforms on open oceanic shores. We propose here a tephrastratigraphical scheme for different Middle-Late Holocene facies.
    • Isotopic Analysis and Cycling of Dissolved Inorganic Carbon at Lake Biwa, Central Japan

      Nakamura, Toshio; Kojima, Sadao; Ohta, Tomoko; Oda, Hirotaka; Ikeda, Akiko; Okuno, Mitsuru; Yokota, Ki-Ichiro; Mizutani, Yoshihiko; Kretschmer, Wolfgang (Department of Geosciences, The University of Arizona, 1998-01-01)
      This paper reports on concentrations and carbon isotopic results of dissolved inorganic carbon (DIC) in water samples collected at four locations and from several depths in Lake Biwa, central Japan, covering every season of the year, starting in the spring of 1995. Depth profiles of DIC concentration and DIC delta-13C showed a strong seasonal pattern, as a result of vertical mixing of the lake water in winter and early spring, or lack of mixing in the other seasons. No seasonal change in DIC Delta-14C depth profiles was recognizable, mainly owing to the wide scatter of DIC Delta-14C. Values typically ranged from 0.47 to 0.65 mmol kg-1 for DIC concentration, and from -4 to -8 per mil from +10 to +80 per mil for DIC delta-13C and DIC Delta-14C, respectively, for the Lake Biwa water.
    • 14C Dating of Terrestrial Moss in Tern Lake Deposits, Antarctica

      Shen, Chengde; Liu, Tungsheng; Yi, Weixi; Sun, Yanmin; Jiang, Mantao; Beer, Jürg; Bonani, Georges (Department of Geosciences, The University of Arizona, 1998-01-01)
      Accurate radiocarbon ages were obtained from terrestrial moss from two drill holes in Tern Lake deposits, Antarctica, using liquid scintillation counting (LSC) and accelerator mass spectrometry (AMS). The results show that the lake deposits have been accumulating since the end of the last glacial epoch ca. 12,600 cal BP at the rate of 0.13-1.1 mm a-1. We discuss the validity of 14C ages of Antarctic lake deposits, with respect to the latitude effect of 14C productivity, the reservoir effect, the environment effect and the hard-water effect.
    • 14C Studies of Natural Ice

      Wilson, A. T. (Department of Geosciences, The University of Arizona, 1998-01-01)
      There are many kinds of natural ice found on our planet. These include glacier ice, ice sheets, cave ice, massive ground ice, ice-wedge ice and permafrost ice. The problems associated with the recovery and dating of the CO2 and other gases contained in these kinds of ice is reviewed. New data are presented on various kinds of natural ice. How this kind of data can be used to help determine the origin and history of natural ice samples is discussed, along with the kind of paleoclimatic information that might be obtained from natural ice samples.
    • America's Oldest Basketry

      Berger, Rainer; Bendat, Millie; Parker, Andrea (Department of Geosciences, The University of Arizona, 1998-01-01)
      We have determined the earliest calibrated dates on three types of basketry from the Great Basin of western North America. The oldest twined basketry dates to 10,380-10,918 cal BP, reed duck decoys to 2355-2773 cal BP, and wooden sandals of sagebrush bark or twined tule to 9247-10,375 cal BP and 9242-9836 cal BP, respectively.
    • AMS 14C Dating Historic Eruptions of the Kirishima, Sakurajima and Kaimondake Volcanoes, Southern Kyushu, Japan

      Okuno, Mitsuru; Nakamura, Toshio; Kobayashi, Tetsuo (Department of Geosciences, The University of Arizona, 1998-01-01)
      In the historic period, several large eruptions were recorded from Kirishima, Sakurajima and Kaimondake volcanoes in southern Kyushu, Japan. Estimated dates of volcanic activity were established on these volcanoes through historical documentation of major eruption events. This study presents the correspondence between these documents and the records of AMS 14C dating of soils underlying tephra layers. We conclude that AMS 14C dates of soil materials can be useful in correlating tephra layers with documentary records of eruption.
    • Duration of Tell Settlements at Four Prehistoric Sites in Hungary

      Hertelendi, Ede; Svingor, Éva; Raczky, Pál; Horváth, Ferenc; Futó, István; Bartosiewicz, László (Department of Geosciences, The University of Arizona, 1998-01-01)
      The chief objective of this paper is to improve our understanding of the Neolithic in eastern Hungary using absolute chronological data. To accomplish this we calibrated new measurements as well as previously published dates. The up-to-date, standardized evaluation of 147 calibrated measurements showed temporal overlaps between archaeological cultures defined on the basis of ceramic styles. The average timespan of tell settlements of 285 yr was obtained using radiocarbon dates from four major settlements in eastern Hungary: Berettyóújfalu-Herpály, Hódmezóvásáhely-Gorzsa-Cukortanya, Öcsöd-Kováshalom and Polgár-Csószhalom.
    • Minimal Extension Phases of Unteraarglacier (Swiss Alps) During the Holocene Based on 14C Analysis of Wood

      Hormes, Anne; Schlüechter, Christian; Stocker, Thomas F. (Department of Geosciences, The University of Arizona, 1998-01-01)
      Tree trunks and wood fragments in minerotrophic fen peat that accumulated as the result of a jökulhlaup in the outwash plain of Unteraarglacier were radiocarbon-dated using conventional beta -counting. Different pretreatment methods were tested on two wood samples to determine the reliability of our dates. We dated the wood compounds after extended acid-alkali-acid treatment, as well as extraction of cellulose and lignin. The results of the samples Picea (B-6687) and Pinus cembra (B-6699) show insignificant differences of <1 sigma. The 14C dates represent retreat of Unteraarglacier due to warmer and/or drier phases in the Holocene compared to modern climate conditions. The glacier was at least several hundred meters smaller in extent than today ca. 8100-7670 BP, 6175-5780 BP, 4580-4300 BP, 4100-3600 BP and 3380-3200 BP. The 14C dates suggest a ca. 2000-yr cyclicity of tree growth in the area covered by the present Unteraarglacier. The most intense warm and dry period occurred between 4100 BP (probably extending back to 4580 BP) and 3600 BP, with growth of fen peat between 3800 and 3600 BP attributed to wetter conditions.
    • Early Bronze Jericho: High-Precision 14C Dates of Short-Lived Palaeobotanic Remains

      Bruins, Hendrik J.; van der Plicht, Johannes (Department of Geosciences, The University of Arizona, 1998-01-01)
      Reliable series of high-precision radiocarbon dates in a stratified archaeological context are of great importance for interdisciplinary chronological and historical studies. The Early Bronze Age in the Near East is characterized by the beginning of the great civilizations in Egypt and Mesopotamia, as well as by urbanization in the Levant. We present stratified high-precision dates of short-lived material of Tell es-Sultan (Jericho), covering Late Proto-Urban/EB I, EB II and EB III layers from Trench III. Our calibrated dates, refined by Bayesian sequence analysis involving Gibbs sampling, are ca. 150-300 yr older than conventional archaeological age assessments. The corpus of 14C dates measured in the first decades after the discovery of 14C dating should not be taken too seriously. The 14C dates of Jericho measured by the British Museum 14C laboratory in 1971 appear to be erroneous.
    • Chronology of the Burial Finds from Scythian Monuments in Southern Siberia and Central Asia

      Sementsov, Anatoly A.; Zaitseva, G. I.; Görsdorf, J.; Nagler, A.; Parzinger, H.; Bokovenko, N. A.; Chugunov, K. V.; Lebedeva, L. M. (Department of Geosciences, The University of Arizona, 1998-01-01)
      We present here new radiocarbon dates for the different barrows (burial mounds) of the nomadic tribes of the Scythian period in the Khakassia and Tuva regions (Central Asia). The time scale of these barrows is compared with the elite barrows of the Sayan-Altai. In agreement with archaeological evidence, some barrows in Khakassia are chronologically close in time to the Arzhan barrow. The first 14C dates produced for the barrows from the Tuva region belong to a later Scythian period, compared with the elite Arzhan barrow. We determined the final stage of the barrow construction, but to establish the starting time, more dates are necessary (both by dendrochronology and 14C).
    • Climatic Events and Upper Paleolithic Chronology in the Dniester Basin: New 14C Results from Cosautsi

      Haesaerts, Paul; Borziak, Ilic; van der Plicht, Johannes; Damblon, Freddy (Department of Geosciences, The University of Arizona, 1998-01-01)
      We discuss the radiocarbon chronology of the loess deposited during the Upper Pleniglacial (Isotope Stage II) for the key site of Cosautsi (Republic of Moldova), which presents some major problems in 14C dating. Special care was paid to accurate microstratigraphic positioning of samples, collection of top-quality material (mainly conifer charcoal), and selection of uncontaminated pieces for dating and crossdating with bones by accelerator mass spectrometry (AMS) and/or conventional 14C dating. The results provide reliable and precise information on the sedimentation processes, the succession of short climatic events and the cycle of recurrent human settlements on the site between approximately 20,000 and 16,000 BP. Two sets of climatic improvements can be ascribed to interstadial oscillations named, successively, Cosautsi VI (19,500-19,000 BP) and Cosautsi V (18-17,500 BP).
    • Wadi Shaw 82/52: 14C Dates from a Peridynastic Site in Northwest Sudan, Supporting the Egyptian Historical Chronology

      Lange, Mathias (Department of Geosciences, The University of Arizona, 1998-01-01)
      In the framework of the interdisciplinary project "Settlement History of the Eastern Sahara" at the Universitat zu Koln, a large number of sites were excavated during the 1980s in northern Sudan, where the Laqiya-region with the Wadi Shaw and Wadi Sahal was one of the main research areas. About 150 sites have been surveyed and partly excavated. One of these sites, Wadi Shaw 82/52, yielded sherds of a Maidum bowl, which is dateable to the Egyptian IVth and Vth Dynasty. This site was dated by four radiocarbon dates. The dates are compared with the historical chronology of Egypt for the IVth and Vth Dynasty, and are shown to be in good agreement.
    • Apparent 14C Ages of Marine Mollusk Shells from a Greek Island: Calculation of the Marine Reservoir Effect in the Aegean Sea

      Facorellis, Yorgos; Maniatis, Yannis; Kromer, Bernd (Department of Geosciences, The University of Arizona, 1998-01-01)
      The excavation of the Cyclope cave, situated on the deserted island of Youra in the Northern Sporades (39 degrees 22'N, 24 degrees 10'E), revealed material of marine and terrestrial origin in undisturbed layers, suitable for radiocarbon dating. In some cases, material from different reservoirs was found together in the same archaeological layer. This research had two aims. The first was the dating of charcoal-seashell pairs in order to determine the marine reservoir effect in this region, based on samples with ages spanning from the end of the 8th millennium to the beginning of the 7th millennium BC. The second aim was dating the stratigraphy of this site, by using the calculated Delta-R value in conjunction with the marine calibration curve. This enabled the accurate calibration of the 14C ages of marine samples found in layers without charcoal pieces. The results show that this is the oldest human settlement ever found on an island in the Aegean Sea.
    • Application of 14C Data for the Estimation of Sphagnum Peat Increment in Estonian Ombrotrophic Mires

      Punning, J.-M.; Koff, Tiiu (Department of Geosciences, The University of Arizona, 1998-01-01)
      We calculated apparent increment values based on the radiocarbon dates of 21 Estonian ombrotrophic mires (raised bogs). For short periods, the values vary significantly, but the integrated increment for the total complex of ombrotrophic peat shows a strong increasing tendency with decreasing peat age. This is probably due to the decay of accumulated organic matter. Our hypotheses concern the mechanisms of decay and methods for increasing the reliability of the interpolation and extrapolation of 14C data.
    • Dating Grimes Graves

      Ambers, Janet (Department of Geosciences, The University of Arizona, 1998-01-01)
      More radiocarbon analyses have been produced for the Neolithic flint mines of Grimes Graves than for any other site with which the British Museum's Radiocarbon Laboratory has been involved. Despite this heavy concentration of effort, a recent review of these figures concluded that poor sample selection, combined with a lack of sufficient quality assurance procedures, severely limit the use that can be made of this database. To overcome these difficulties, a redating program has been undertaken using a carefully selected subset of the original material. In this paper I discuss the flaws in the original data set, due to both technical and sampling problems; set out ways to avoid similar problems in the future, with particular reference to quality assurance; and discuss the new results and their archaeological implications.
    • Temporal Changes of the 14C Reservoir Effect in Lakes

      Geyh, Mebus A.; Schotterer, U.; Grosjean, M. (Department of Geosciences, The University of Arizona, 1998-01-01)
      Conventional radiocarbon dates for sediment samples from aquatic systems and of coeval terrestrial samples deviate from each other due to the reservoir effect. The reservoir correction is usually assumed to be constant with time for a specific aquatic system. Our studies confirm that seasonal and secular changes are frequent and are governed by the limnological conditions. Lakes have two principal sources of 14C: atmospheric CO2 and the total dissolved inorganic carbon (TDIC) of the entering groundwater and runoff. The former has values of ca. 100 pMC; the latter usually has a 14C value well below 100 pMC. Atmospheric CO2 enters the lake by exchange via its surface. The proportions of these two kinds of input determine the magnitude of the reservoir correction in freshwater lakes. It is mainly a function of the volume/surface ratio of the lake and, consequently a function of the water depth. The surface of lakes with outflow does not change when sedimentation decreases the depth of the water. The depth of Schleinsee Lake in southern Germany has decreased from 30 to 15 m since ca. 9000 BP. As a result, the reservoir correction has decreased from ca. -1550 to -580 yr. In contrast, the depth of Lake Proscansko in Croatia increased with growth of the travertine dam and the reservoir correction changed from ca. -1790 to -2650 yr during the last 8800 yr. The largest fluctuations of lake levels occur in closed lakes in arid regions when the climate changes from humid to arid and vice versa. As a result, the reservoir correction of the 14C dates for the total organic fraction from Lejía Lake in the Atacama Desert of Chile varied between <-1800 yr and -4700 yr over a period of only 1800 yr between 11,500 and 9700 BP. The corresponding reservoir correction for the marl fraction is much higher. In summary, accurate and reliable 14C dating of lake sediments requires a study of the temporal changes of the reservoir effect by analysis of both the organic and marl fractions. The most reliable 14C dates are obtained from terrestrial plant remains.
    • Carbon Isotope Variations and Chronology of the Last Glacial-Interglacial Transition (14-9 ka BP)

      Turney, Chris M.; Harkness, Douglas D.; Lowe, J. J. (Department of Geosciences, The University of Arizona, 1998-01-01)
      We present delta-13C data from both bulk organic sediment samples and terrestrial plant macrofossils from five high-resolution sedimentary sequences from the United Kingdom from which extensive multiproxy data sets have been obtained. These span the last glacial-interglacial transition. Chronological control has been provided by radiocarbon dating and/or tephrochronology. The results demonstrate that significant shifts in bulk organic delta-13C can be identified at key climatic transitions in most of the sites. The data are affected by site-specific influences that restrict their use as chronological markers. However, terrestrial plant macrofossil records are more consistent and reveal shifts that appear to be synchronous and which therefore offer a basis for interregional correlation as well as significant paleoenvironmental information.
    • Using 14C as a Tracer of Carbon Accumulation and Turnover in Soils

      Milton, G. M.; Kramer, S. J. (Department of Geosciences, The University of Arizona, 1998-01-01)
      Three very different Canadian soils—clay soils of the St. Lawrence Lowlands, sandy forest soils of the Ottawa Valley, and organic-rich sediments from a wetland on the Canadian Shield—have been cored, sliced and separated into different density fractions, and the radiocarbon content of these soil fractions measured. In two of the areas sampled, cores were obtained close to operating nuclear reactors, as well as from beyond their region of influence. As a consequence, it has been possible to ascertain the depths of penetration of both the weapons-testing pulse (peaking in 1963), and a 25-50-yr chronic reactor input of 14C. The percentage of carbon stored in different density fractions varied with soil type. Turnover times for bulk soil organic carbon, estimated from soil degassing rates, have been compared with those predicated on the residual "bomb" 14C in background cores, and/or on the ratio of reactor-emitted 14C retained in the soils to the total deposited during the lifetime of operation. Residence times for the heavy carbon fraction present at depths below the influence of anthropogenic inputs have also been estimated. The accumulated data will be incorporated in a revised soil model, adjusted for the parameters deemed to be most important to carbon turnover rates under Canadian conditions.
    • The 14C Age of Palsas in Northern Eurasia

      Vasil, Chuk K.; Vasil, Chuk C. (Department of Geosciences, The University of Arizona, 1998-01-01)
      We discuss results of 14C dating peat of palsa of different regions of Northern Eurasia. We apply these dates to determine the age of active palsa growth during different periods of the Holocene in permafrost zone.