• 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.
    • 14C Ages of Terrestrial Macrofossils from Lago Grande di Monticchio (Italy)

      Hajdas, Irka; Bonani, Georges; Zolitschka, Bernd; Brauer, Achim; Negendank, Jörg W. (Department of Geosciences, The University of Arizona, 1998-01-01)
      Lago Grande di Monticchio (Italy) contains long sedimentary records of >75 ka (Zolitschka and Negendank 1996). In a joint European project (Creer and Thouveny 1996), vegetation history and climatic changes for this part of the Mediterranean have been reconstructed (Watts, Allen and Huntley 1996; Watts et al. 1996). In addition to the time scale based on annual laminations and sedimentation rate, tephra layers and pollen spectra, radiocarbon dating was applied for the last 40 ka. Previous studies have shown that the age of bulk sediment from Lago Grande di Monticchio, which is a maar lake at the flanks of Mt. Vulture, was influenced by "dead carbon" of volcanic origin dissolved in the lake water. Thus, 14C dating of the record is problematic and must be limited to dating macrofossils of terrestrial origin. From a set of sediment samples, macrofossils were selected and dated using accelerator mass spectrometry (AMS). A 14C time scale based on seven data points between 9000 and 24,000 BP is compared with other dating of the record based on varve counting and tephrochronology (Zolitschka 1996).
    • 14C AMS Dating of Icelandic Lake Sediments

      Sveinbjörnsdóttir, Árný E.; Heinemeier, Jann; Kristensen, Peter; Rud, Niels; Geirsdóttir, Áslaug; Harđardóttir, Jóhann (Department of Geosciences, The University of Arizona, 1998-01-01)
      We report an age-depth profile for the sediments of the Lake Hestvatn, southern Iceland, based on 14C analyses of the organic fraction of bulk sediment samples, molluscs and foraminifera. Our age-depth curve is supported by the occurrence of the well-dated Vedde ash in the lowermost part of the sediments. Comparison of foraminifera dates with the age of the Vedde ash indicates a reservoir age of ca. 400 yr. The results suggest that the sediments at Hestvatn accumulated in a marine environment until ca. 8700 BP and thereafter in freshwater. Owing to the lack of terrestrial macrofossils and the low concentration of molluscs and foraminifera, we were forced to attempt to date most of the core with the organic fraction of the bulk sediment samples. We found, however, that this fraction is not homogeneous in density or 14C age. We believe that during sample pretreatment we managed to isolate a light organic fraction, which closely represents the true age of the sediment, whereas the denser fraction yields ages that are too high. This age diversity may to some extent be explained by the large drainage area of the lake, from which plant remains of different ages may have been washed into the lake.
    • 14C and 18O in Siberian Syngenetic Ice-Wedge Complexes

      Vasil'chuk, Y. K.; Vasil'chuk, A. C. (Department of Geosciences, The University of Arizona, 1998-01-01)
      We discuss the possibility of dating ice wedges by the radiocarbon method. We show as an example the Seyaha, Kular and Zelyony Mys ice wedge complexes, and investigated various organic materials from permafrost sediments. We show that the reliability of dating 18O variations from ice wedges can be evaluated by comparison of different organic materials from host sediments in the ice wedge cross sections.
    • 14C and 234U-Excess Dating of Groundwater in the Haifa Bay Region, Israel

      Rogojin, Vasily; Carmi, Israel; Kronfeld, Joel (Department of Geosciences, The University of Arizona, 1998-01-01)
      Radiocarbon activities and uranium isotopic disequilibria were measured in water samples from both the sandy Pleistocene coastal aquifer and within the upper Cretaceous Judea Group carbonate aquifer of northwestern Israel. The samples in both aquifers exhibit a decrease in 14C activity that is concomitant to the growth in 234U-excess. This suggests that under specific conditions, 234U-excess dating of groundwater can be used to corroborate 14C dates, while offering the possibility of extending the range of dating of groundwater beyond that of 14C.
    • 14C Chronology of Archaeological Sites in European Russia and Changes in Environmental Processes: A Database Investigation

      Zaitseva, Ganna I.; Dergachev, Valentin A.; Timofeev, Vladimir; Sementsov, Anatoly A. (Department of Geosciences, The University of Arizona, 1998-01-01)
      A large number of 14C dates for archaeological sites in European Russia have been entered into a new database. The database includes >1500 dates for ca. 500 archaeological sites. Because European Russia is a very large area, the database includes subdivisions of territories and regions. We analyzed our 14C dates according to archaeological periods (Paleolithic through Medieval period) and made a comparison with environmental (climatic) parameters. Our database for archaeological sites and monuments offers new possibilities for correlation between the development of ancient cultures and natural-climatic processes.
    • 14C Chronology of Stone Age Cultures in the Russian Far East

      Kuzmin, Yaroslav V.; Jull, A. J. T.; Orlova, Lyobov A.; Sulerzhitsky, Leopold D. (Department of Geosciences, The University of Arizona, 1998-01-01)
      Ca. 150 unequivocal 14C dates from the prehistoric cultures in the Russian Far East can be used to elucidate chrono-cultural boundaries in that region. Microblade technology started as early as ca. 20,000 BP, and continued to exist in the middle Amur River basin until ca. 10,500 BP, and in Primorye until ca. 7800 BP. The emergence of pottery-making in the lower Amur River basin goes back to ca. 13,300 BP. The transition from Upper Paleolithic to Neolithic took place during the time interval 13,300-7800 BP and pottery was widely spread in the Russian Far East by ca. 6700-8400 BP. The first evidence of shellfish collection is estimated to ca. 6400 BP at Peter the Great Gulf coast, Sea of Japan. The beginning of agriculture in Primorye, based on finding of both millet seeds (Setaria italica L.) and pollen of cultivated cereals (Cerealia), is 14C-dated to ca. 4200-3700 BP (ca. 1980-2900 cal BC). The Neolithic/Early Iron Age boundary was estimated at ca. 3100-3300 BP (1400-1600 cal BC) in the mainland Russian Far East, and to ca. 1800-2300 BP (400 cal BC-200 cal AD) on the Sakhalin and southern Kuril Islands.
    • 14C Dating Ancient Japanese Documents

      Oda, Hirotaka; Nakamura, Toshio; Furukawa, Michiaki (Department of Geosciences, The University of Arizona, 1998-01-01)
      We measured radiocarbon ages of 11 pieces of ancient Japanese documents by accelerator mass spectrometry (AMS). The purpose of this study is to compare the relationship between the calibrated 14C age and the historical age of Japanese paper samples. Calibrated ages of nine pieces agree with their historical ages, indicating that Japanese ancient documents can be used for 14C dating in the recent historic period. On the other hand, the 14C age of paper that was used for reinforcement of a sutra is ca. 300 yr older than the historical age of the sutra. This shows that the sutra was repaired with old paper.
    • 14C Dating and Stable Carbon Isotopes of Soil Organic Matter in Forest-Savanna Boundary Areas in the Southern Brazilian Amazon Region

      Pessenda, L. C. R.; Gouveia, S. E. M.; Aravena, Ramon; Gomes, B. M.; Boulet, Rene; Ribeiro, A. D. S. (Department of Geosciences, The University of Arizona, 1998-01-01)
      This study, which was carried out in the southern Brazilian Amazon region (Rondonia state and Humaita, Southern Amazon state), presents and discusses the significance of carbon isotope data measured in soil profiles collected across natural boundaries of forest to savanna vegetation. The main objective of this study was to evaluate the expansion-regression dynamics of these vegetation units in relation to climate changes during the Holocene. 14C data from charcoal, soil organic matter (SOM) and its component humin fraction indicate that the organic matter in the studied soils is essentially Holocene in origin. 13C data indicate that C3 type plants were the dominant vegetation at all study areas in the early Holocene, and during the entire Holocene, in the forest sites of Central Rondonia state and in the forest site 50 km from the city of Humaita. 13C data also indicate that C4 plants have influenced significantly the vegetation at the transitional forest and the Cerrado (wooded savanna) sites of Southern Rondonia state and the forest ecosystem located 20 km from the Humaita city. These typical C4 type isotopic signatures probably reflect a drier climate during the mid-Holocene. The 13C records representing probably the last 3000 yr show an expansion of the forest, due to a climatic improvement, in areas previously occupied by savanna vegetation. These results and other published data for the Amazon region indicate that the areas representing today's forest-savanna boundaries have been determined by significant vegetation changes during the Holocene. The boundary between forest and savanna vegetation seems to be quite sensitive to climatic change and should be the focus of more extensive research to correlate climate and past vegetation dynamics in the Amazon region.
    • 14C Dating of a Neolithic Field System at Céide Fields, County Mayo, Ireland

      Caulfield, Seamas; O'Donnell, R. G.; Mitchell, P. I. (Department of Geosciences, The University of Arizona, 1998-01-01)
      Ceide Fields is a 12 km2 Neolithic field system in North Mayo in the west of Ireland. The fields, enclosed by an integrated system of stone walls, have been preserved intact by a cover of blanket bog that is >4 m deep in places. At many locations within this blanket bog the stumps of ancient pines (Pinus sylvestris) are found in situ. The pine roots in most cases are either on the surface of the mineral soil under the peat or at an intermediate level in the peat itself. The age of the trees in the bog overlying Ceide Fields is therefore of great significance for the dating of the fields, as the trees must be younger than the bog in which they are growing, which in turn must be younger than the field system beneath it. We present here the dates (N = 15) for pine trees from the bogs overlying Ceide Fields and the dates (N = 29) of pine trees from other areas of the North Mayo blanket bog. We compare these pine dates with published dates of peat associated with a major pollen analytical study from within the fields and with published dates for bog pine from Scotland. The results of the study suggest that the dates for the construction and period of use of Ceide Fields and other Neolithic pre-bog field systems in North Mayo are older than anticipated and that the date for initiation of blanket bog in many parts of North Mayo is also older than previously estimated. Further, the range of dates of the pine stumps indicates a synchronic event contemporary with a similar phenomenon observed in Scotland.
    • 14C Dating of Laminated Sediments from Loch Ness, Scotland

      Cooper, M. C.; O'Sullivan, P. E.; Harkness, D. D.; Lawson, E. M.; Bull, D.; Kemp, A. E. S.; Peglar, Sylvia M.; Matthews, Nina M.; Jones, R. I.; Shine, A. J. (Department of Geosciences, The University of Arizona, 1998-01-01)
      Radiometric and AMS radiocarbon dating of a 6-m sediment core from Loch Ness, Scotland, indicates that it represents perhaps the very end of the Late Pleistocene, and the first ca. 7500 yr of the Holocene. Counts of laminations observed in the Holocene section of the core suggest that they are present in sufficient number to constitute annual laminations (varves), an hypothesis consistent with the pollen record, which contains a sequence of zones representative of the Early, Middle and part of the Late Holocene regional vegetation history. On the basis of BSEM and X-ray studies of sediments, and modern seston trap data, the laminations are believed to be produced by winter floods, which introduce increased silt loading into the Loch. Sediment for the rest of the year is mostly composed of clay-sized material. This hypothesis is being further tested, however, by continuing sedimentological and microfossil studies. Time-depth relations for the core based on calibrated 14C dates and lamination counts, respectively, illustrate the close correspondence between the two sets of data. The latter are therefore now being used to develop a varve chronology for the Holocene for Loch Ness. This will then in turn be used for further chronological studies, and for investigations of palaeoclimatic variations over the eastern North Atlantic, to which the signal of lamination thickness in the sediments is thought to be particularly sensitive. They may also eventually be used for calibration studies, employing 14C dating of specific carbon compounds, or groups of compounds extracted from the sediment using modern organic geochemical methods.
    • 14C Dating of Late Pleistocene-Holocene Events on Kunashir Island, Kuril Islands

      Bazarova, V. B.; Razjigaeva, N. G.; Grebennikova, T. A.; Ganzey, L. A.; Mokhova, L. M.; Korotky, A. M.; Sulerzhitsky, L. D. (Department of Geosciences, The University of Arizona, 1998-01-01)
      Kunashir Island is a very important site for paleoenvironmental reconstructions. Until recently, very little information on Quaternary deposits was available. We studied the environmental evolution of this oceanic island under the influence of geomorphological processes, volcanism and strong marine currents. This paper presents new data that allow a detailed reconstruction of the environmental development of Kunashir Island during the Late Pleistocene-Holocene, based on ca. 80 radiocarbon dates and diatom, pollen and sedimentological data. The vegetation development reflects climate changes and warm/cold current migrations.
    • 14C Dating of Modern Marine and Estuarine Shellfish

      Hogg, A. G.; Higham, T. G.; Dahm, J. (Department of Geosciences, The University of Arizona, 1998-01-01)
      We measured the 14C content of 36 living marine molluscs from Tairua Harbour and the rocky coast on the Coromandel Peninsula of New Zealand. We identified species suitable for radiocarbon dating and show that the open marine intertidal zone is enriched in 14C compared to the open marine subtidal zone or estuary. We also found a uniform 14C distribution in the Tairua Harbour, by analyzing samples of the estuarine bivalve Austrovenus stutchburyi collected up to 5 km from the harbor entrance.
    • 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.
    • An Extended Prehistoric Well Field in the Opencast Mine Area of Zwenkau, Germany

      Stäuble, Harald; Hiller, Achim (Department of Geosciences, The University of Arizona, 1998-01-01)
      In the opencast mine area of Zwenkau, Germany, many prehistoric wells and pits have recently been excavated. In this region there is generally no bone preservation and charred seeds are rare, seldom encountered in a reliable archaeological context, whereas charcoal is frequently found. From an archaeological point of view, however, charcoal from wood is not as reliable for radiocarbon dating as short-lived materials. Fortunately, many deep features were found where wood has been preserved. Over a dozen structures turned out to be prehistoric wells, some of them typologically dated by ceramics to between Early Bronze Age and Early Middle Ages. For other features without archaeological finds, 14C dating was the only way to get an age. Analysis showed that different types of wells were constructed by the same culture. On the other hand, the same constructions are not characteristic for a defined cultural period and were applied over a time span of three millennia.
    • 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.