• Radiocarbon Age of Vertisols and its Interpretation Using Data on Gilgai Complex in the North Caucasus

      Kovda, Irina; Lynn, Warren; Williams, Dewayne; Chichagova, Olga (Department of Geosciences, The University of Arizona, 2001-01-01)
      Radiocarbon dates were analyzed to assess Vertisols age around the world. They show an increase of radiocarbon age from mainly modern-3000 BP in 0-100 cm layer up to 10,000 BP at a depth 100-200 cm. Older dates reflect the age of parent material. The inversion of 14C dates seems to be a frequent phenomenon in Vertisols. A series of new dates of Vertisols from gilgai microhigh, microslope and microlow in the North Caucasus was done in order to understand the nature of this inversion. 14C age in the gilgai soil complex ranges from 70 +/45 BP in the microlow to 5610 +/180 BP in the microhigh. A trend of similar depths being younger in the microslope and microlow was found. We explain this by intensive humus rejuvenation in the microlows due to water downward flow. The older date in the microhigh represents the old humus horizon sheared laterally close to the surface and preserved by impermeable water regime. We explain inversions of 14C age-depth curves by the sampling procedures. In a narrow pit, genetically different parts of former gilgai could easily be as a genetically uniform soil profile. Because of this strong microvariability, Vertisols require sampling in a trench accounting for gilgai elements, even when gilgai are not obvious.
    • Radiocarbon Age Profiles and Size Dependency of Mixing in Northeast Atlantic Sediments

      Brown, Louise; Cook, Gordon T.; MacKenzie, Angus B.; Thomson, John (Department of Geosciences, The University of Arizona, 2001-01-01)
      In recent years, the most common technique for radiocarbon dating of deep-ocean sediments has been accelerator mass spectrometry (AMS) analysis of hand-picked planktonic forminifera (forams). Some studies have exposed age offsets between different sediment size fractions from the same depth within a core and this has important implications when establishing a chronological framework for palaeoceanographic records associated with a particular sediment component. The mechanisms generating the age offsets are not fully understood, a problem compounded by the fact that the fraction defined as "large"varies between different studies. To explore this problem, we dated samples of hand-picked forams from two Biogeochemical Ocean Flux Study (BOFS) cores, for which the presence of an offset between the bulk carbonate and >150 micrometers foraminiferal calcite had already been demonstrated. The presence of a constant age offset between bulk carbonate and coarse fraction material at the two BOFS sites has been confirmed, but the magnitude of the offset is dependent on whether a simple size-separation technique or hand-picking of well-preserved forams is applied. This may be explained if the selection of well preserved forams biases the sample towards those specimens that have spent least time in the surface mixed layer (SML) or have undergone less size selective mixing. Modeling of the 14C profiles demonstrates that SML depth and sediment accumulation rates are the same for both the bulk and coarse sediment fractions, which is consistent with the hypothesis that size-selective mixing is responsible for the age offset.
    • Radiocarbon Ages of Beach Rocks and Late Holocene Sea-Level Changes in the Southern Part of the Nansei Islands, Southwest of Japan

      Omoto, Kunio (Department of Geosciences, The University of Arizona, 2001-01-01)
      Beach rock is a good indicator of the past sea levels, as it is considered to have been formed within the range of intertidal zone. Radiocarbon dates of beach rocks collected from Iriomote Island, Ishigaki Island, and Miyako Island, in the southern part of the Nansei Islands, indicate that the beach rocks were formed between around 4000 BP and 400 BP. Late Holocene sea-level changes were revealed based on the elevations and 14C dates of the beach rocks. The results indicate that the sea level was similar to the present one for at least the past 4000 BP. Isotopic fractionations (delta-13C) of the beach rocks were between +9.4 per mil and -0.8 per mil, suggesting a different origin for calcium carbonate.
    • Radiocarbon AMS Dates for Paleolithic Cave Paintings

      Valladas, H.; Tisnérat-Laborde, N.; Cachier, H.; Arnold, M.; de Quirós, F. Bernaldo; Cabrera-Valdés, V.; Clottes, J.; Courtin, J.; Fortea-Pérez, J. J.; Gonzáles-Sainz, C.; et al. (Department of Geosciences, The University of Arizona, 2001-01-01)
      Advances in radiocarbon dating by accelerator mass spectrometry (AMS) have made it possible to date prehistoric cave paintings by sampling the pigment itself instead of relying on dates derived from miscellaneous prehistoric remains recovered in the vicinity of the paintings. The work at the Laboratoire des Sciences du Climat et de l’Environnement (LSCE) concentrated on prehistoric charcoal cave paintings from southern France and northern Spain. In most caves, pigment samples were collected from several paintings, and in some instances the sample size allowed for multiple independent measurements on the same figure, so that the coherence of the calculated dates could be tested. Before being dated, each specimen was subjected to a thermal treatment preceded by an acid and basic treatment of intensity commensurate with the sample size. Nine bison drawings from three caves in the Cantabrian region of Spain—two from Covaciella, three from Altamira, and four from El Castillo—were sampled and dated. The 27 dates fell between 13,000 and 14,500 BP, allowing us to attribute the drawings to the Magdalenian period. The 24 dates for 13 drawings in the Cosquer cave indicated two distinct periods of painting activity—one around 28,000 BP and the other around 19,000 BP. The Chauvet cave paintings turned out to be the oldest recorded to date, as five dates fell between 32,000 and 31,000 BP. After discussing the sample preparation protocol in more detail, we will discuss the ages obtained and compare them with other chronological data.
    • Radiocarbon as a Tool for Modeling the Diachronic Analysis of the Occupation Phases at the Velzeke Site (Belgium)

      Van Strydonck, Mark; De Mulder, Guy; Deschieter, Johan (Department of Geosciences, The University of Arizona, 2001-01-01)
      The oldest traces of Velzeke go back to the Late Bronze Age and Early Iron Age, followed by a Gallo-Roman settlement and a later medieval village. Although the excavations document the history of the site in general, radiocarbon was used to clarify the successive phases within each feature. The results showed that the ditches at the Roman settlement and the neighboring temple area were already used during the Late Iron Age. The filling up of the ditches could be 14C correlated to a Gallo-Roman occupation phase. The oldest Christian cemetery at the site of the medieval church predates the construction of an important Carolingian stone building (9th to 10th centuries.). The stratigraphically lowest sediments of the ditches, surrounding the Carolingian church, are synchronous with the latest fill of the Iron Age ditch. According to historical and toponymical sources the area of the Iron Age ditch becomes at that time part of a medieval agricultural field system.
    • Radiocarbon Chronology of the Earliest Neolithic Sites in East Asia

      Kuzmin, Yaroslav V.; Keally, Charles T. (Department of Geosciences, The University of Arizona, 2001-01-01)
      The radiocarbon age of the earliest pottery from Russian Far East-Gromatukha and Osipovka cultures-is between around 13,300 BP and around 10,400 BP. This shows that the Amur River basin was one of the centers of origin of pottery in East Asia, at the end of the Pleistocene. Today, there are three areas within East Asia with pottery-associated 14C dates between around 14,000 BP and 13,000 BP—Southern China, the Japanese Isles, and Russian Far East.
    • Radiocarbon Dating of Charred Residues on the Earliest Pottery in Japan

      Nakamura, Toshio; Taniguchi, Yasuhiro; Tsuji, Sei Ichiro; Oda, Hirotaka (Department of Geosciences, The University of Arizona, 2001-01-01)
      Recently, primitive-type pottery was discovered in the Russian Far East, China, and Japan. Radiocarbon ages of far earlier than 10,000 BP have been obtained, relating directly or indirectly to the pottery. As an example of these very old 14C ages for incipient pottery, we report here 14C ages of charred adhesions on five potsherds and three charred wood fragments that were collected with the archeological artifacts (stone tools from the Chojakubo Culture) in the loam layers at the Odai Yamamoto I site (41 degrees 03'44"N, 140 degrees 033'20"E) in Aomori prefecture, at the northern end of the Japanese main island. The carbonaceous remains on the surface of the potsherds could be ancient food residues or soot from fuel for cooking. These small carbon samples were dated at the Tandetron accelerator mass spectrometry (AMS) 14C dating facility at Nagoya University, as well as by Beta Analytic Co. Ltd. Except for two charred wood 14C dates, 7070 +/40 and 7710 +/40 BP, all five charred-residue samples and one wood charcoal sample gave older 14C ages of 12,680-13,780 BP, corresponding to the period of the Chojakubo Culture in Japan. This culture marks the beginning of the Jomon Culture, which is characterized by pottery usage and bow-and-arrow hunting.
    • Radiocarbon Dating of delta-18O-delta-D Plots in Late Pleistocene Ice-Wedges of the Duvanny Yar (Lower Kolyma River, Northern Yakutia)

      Vasil'chuk, Y. K.; Vasil'chuk, A. C.; Rank, Dieter; Kutschera, Walter; Kim, Jong-Chan (Department of Geosciences, The University of Arizona, 2001-01-01)
      The Duvanny Yar cross-section located in the Lower Kolyma River valley of Northern Yakutia (69 degrees N, 158 degrees E, height above the Kolyma River level 55 m), has been studied and dated in detail by radiocarbon. The sequence mainly consists of sandy loam sediments with large syngenetic ice wedges. Their width at the top is 1-3.5 m. Allochthonous organic material occurs in high content, concentrating as 0.5-0.7 m lenses. Shrub fragments, twigs, and mammoth bones are accumulated in peaty layers. Through interpolation based on a series of 14C dates, dating of the host sediments provides an approximate age for the ice wedges. The 14C dates of various types of organic material are sometimes very close, but not all in agreement. Therefore, the dates do not accurately show the age of the delta-18O and delta-D plots. A new approach is developed to a 14C dating strategy of syncryogenic sediments with high admixture of allochthonous organic material. The main purpose of this study is to consider detection of inversions or disturbances in the syngenetic permafrost sediment at the Duvanny Yar cross-section by 14C date series. Direct accelerator mass spectrometry (AMS) dating of the ice confirmed the relatively young age of ice wedges.
    • Radiocarbon Dating of Porewater – Correction for Diffusion and Diagenetic Processes

      Sivan, Orit; Herut, Barak; Yechieli, Yoseph; Lazar, Boaz (Department of Geosciences, The University of Arizona, 2001-01-01)
      Two simple algorithms are suggested here to correct for the effect of diffusion and diagenetic sulfate reduction on radiocarbon age determination of marine porewater. The correction algorithms were developed from mass balances of sulfate, dissolved inorganic carbon (DIC), and 14C of the DIC (14C(DIC)) in vertical concentrations profiles in porewater starting from the sediment water interface. The algorithms were tested on data collected during our recent study of sediment porewaters extracted from the deep Eastern Mediterranean. The real ages of these porewaters varied from present (top of the core) to approximately 30 ka BP (bottom of the core) covering most of the dynamic range of the 14C method (approximately 5 half lives). These ages were markedly older than the ages calculated from 14C(DIC) analyses by the regular age equation. It is clearly demonstrated that in this case the correction of the apparent age for diffusion across the sediment/water interface is overwhelmingly larger than the correction for the effect of sulfate reduction. The correction for the effect of 14C diffusion alone results in a perfect match between the calculated apparent 14C ages and the real ages of porewater and therefore is the preferred algorithm for correcting apparent ages of porewater.
    • Radiocarbon Dating of the Human Occupation of Australia Prior to 40 ka BP: Successes and Pitfalls

      Fifield, L. K.; Bird, M. I.; Turney, C. S. M.; Hausladen, P. A.; Santos, G. M.; di Tada, M. L. (Department of Geosciences, The University of Arizona, 2001-01-01)
      Charcoal samples from ancient human occupation sites in Australia have been subjected to a rigorous pretreatment and stepped combustion regime in order to explore the possibility that these sites may be older than previous radiocarbon dating had suggested. In one case, the Devil's Lair site in southwest Australia, the methodology has clearly removed vestiges of contamination by more modern carbon and has led to a revised radiocarbon chronology that provides evidence for human occupation of southwest Australia by at least 44 ka BP and probably by 46-47 ka BP. In contrast, charcoal from the Nauwalabila site has been so severely altered that insufficient of the original carbon remains for reliable 14C dating. Finally, where the charcoal is well preserved, such as at the Carpenter's Gap site, the new results provide reassurance that earlier 14C results of approximately 40 ka BP are indeed true ages and are not simply at the limit of the 14C technique.
    • Radiocarbon Dating of Total Soil Organic Matter and Humin Fraction and its Comparison with 14C Ages of Fossil Charcoal

      Pessenda, L. C. R.; Gouveia, S. E. M.; Aravena, R. (Department of Geosciences, The University of Arizona, 2001-01-01)
      During the last decade radiocarbon dating has been used extensively in distinct regions of Brazil to provide information about soil chronology in paleoenvironmental studies. This paper presents 14C dating of soil organic matter (SOM), humin fraction, and charcoal in several soil profiles under natural vegetation from different Brazil locations (north, central, and southeast regions). The main objective is to compare the obtained 14C dating of total SOM with humin, the oldest fraction of SOM. In order to validate the humin ages these data are compared with the age of charcoal collected at similar depths. The 14C ages obtained on charcoal were, in most of the cases, in agreement with the humin fraction considering the experimental errors, or 20% older in average. The dates obtained from total SOM showed significantly younger ages than the humin fraction indicating contamination by younger carbon. These results show the humin fraction is considered a reliable material for 14C dating in soils. However, the humin fraction ages could be assumed as the minimum ages for carbon in soils.
    • Radiocarbon in Seawater at Radioactive Waste Dumping Sites in the Northeast Atlantic and Northwest Pacific

      Povinec, P. P.; Jull, A. J. T.; Burr, G. S. (Department of Geosciences, The University of Arizona, 2001-01-01)
      Radiocarbon has been an important constituent of radioactive wastes dumped in the open ocean and marginal seas as well as wastes released from nuclear reprocessing plants. Therefore, in some regions these sources could have a greater impact on 14C concentration in seawater than global fallout. The high analytical sensitivity of 14C measurement by accelerator mass spectrometry (AMS) allows even tracer amounts of 14C to be found in seawater at radioactive waste dumping sites and their comparison with the global distribution of this radionuclide. Data on measurements of 14C in samples taken at former dumping sites in the northeast Atlantic and northwest Pacific Oceans and in the open ocean are discussed and compared with other anthropogenic radionuclides, namely 3H. Small increases in 14C concentrations observed in some bottom and surface seawater samples collected at the Northwest Pacific Ocean dumping sites require further 14C analyses before final conclusions can be made on possible leakages from dumped radioactive wastes.
    • Radiocarbon in Seawater Intruding into the Israeli Mediterranean Coastal Aquifer

      Yechieli, Yoseph; Sivan, Orit; Lazar, Boaz; Vengosh, A.; Ronen, D.; Herut, Barak (Department of Geosciences, The University of Arizona, 2001-01-01)
      Saline groundwaters from the Israeli coastal aquifer were analyzed for their radiocarbon and tritium content to assess the rate of seawater penetration. The low 14C values (28-88 pMC versus 100-117 pMC in seawater) imply an apparent non-recent seawater source, or water-rock interactions along the penetration route. The latter process is supported by measurable tritium values at some locations, which imply a relatively rapid rate of seawater intrusion. In other locations, low tritium values (<2 T.U.) indicate that recent seawater (<50 yr) did not penetrate inland. The low delta-13C values in saline groundwater (average of -5.3 per mil versus 0 per mil in seawater) indicate that the dissolved carbon pool is comprised of a significant fraction of organic carbon. A linear negative correlation between delta-13C and 14C implies that this organic source is old (low 14C values).
    • Radiocarbon Studies of Peat Bogs: An Investigation of South Kamchatka Volcanoes and Upper Volga Archaeological Sites

      Zaretskaia, N. E.; Ponomareva, V. V.; Sulerzhitsky, L. D.; Zhilin, M. G. (Department of Geosciences, The University of Arizona, 2001-01-01)
      We have undertaken extensive programs of natural radiocarbon measurement to date the evidence for various events buried in peat bogs. Two case studies are described here: 1) the chronological reconstruction of South Kamchatka volcanic eruptions and, 2) investigation of multi-layered archeological sites in the Upper Volga River Basin. Studies of sample composition and peat taphonomy allowed us to determine the source of 14C age deviations and to reconstruct the environmental history of organic matter accumulation. Data sets, obtained from different types of peat bog and containing traces of these Holocene events, are discussed.
    • Spatial Variations of Radiocarbon in the Coastal Aquifer of Israel—Indicators of Open and Closed Systems

      Bruce, Debbie; Friedman, Gerald M.; Kaufman, Aaron; Yechieli, Yoseph (Department of Geosciences, The University of Arizona, 2001-01-01)
      The spatial variation in radiocarbon concentration was studied in the Coastal Aquifer of Israel. Lower concentrations were found in the western section of the aquifer (55-70 pMC) as compared to the eastern section (80-100 pMC). Since no correlation was found between the tritium and radiocarbon values, these variations could not simply be explained by a difference in ages, or by a difference in the degree of old calcite dissolution as similar delta-13C values were found throughout the aquifer. The results are best explained when viewing the differences in 14C values within the same coastal aquifer, where the eastern section of the aquifer is a more open system and the western section is a more closed system. In general, the age of the groundwater in the coastal aquifer was found to be less than 50 years old (14C>55 and measurable tritium).
    • The Age of Upper Paleolithic Sites in the Middle Dnieper River Basin of Eastern Europe

      Abramova, Z. A.; Grigorieva, G. V.; Zaitseva, G. I. (Department of Geosciences, The University of Arizona, 2001-01-01)
      This paper discusses the comparative chronology of Upper Paleolithic sites in the Middle Dnieper River basin, based on archaeological and radiocarbon evidence. Three chronological periods of the development of the Upper Paleolithic are distinguished in this area. According to the data obtained, the third period is similar to the European Magdalenian, yet its economies were different. The base of the subsistence economy for Dnieperian hunters was the procurement of mammoth, while reindeer was the most important for the subsistence of European Magdalenian. The abundance of mammoths and the raw material in the form of mammoth tusks made a deep impact on both the economy and material culture of the hunters in the Dnieper River basin. The 14C dates confirm the chronological subdivision.
    • The Cave of Theopetra, Kalambaka: Radiocarbon Evidence for 50,000 Years of Human Presence

      Facorellis, Yorgos; Kyparissi, Apostolika Nina; Maniatis, Yannis (Department of Geosciences, The University of Arizona, 2001-01-01)
      The cave of Theopetra is located on the northeast side of a limestone rock formation, 3 km south of Kalambaka (21 degrees 40'46"E, 39 degrees 40'51"N), in Thessaly, central Greece. It is a unique prehistoric site for Greece, as the Middle and Upper Paleolithic, Mesolithic, and Neolithic periods are present here, bridging the Pleistocene with the Holocene. Several alternations of the climate during the Pleistocene are recognized in its stratigraphy. Among the most striking finds, two human skeletons, one from the Upper Paleolithic period after the Last Glacial Maximum and one from the Mesolithic period, should be emphasized, while in a deep Middle Paleolithic layer, the oldest human footprints, with remains of fire, were uncovered. During the 13 years of excavation, evidence of human activity suitable for radiocarbon dating was collected, such as charcoal samples from hearths and bones from the two human skeletons. The use of proportional counters for the measurement of 14C in combination with the recent improvement of the calibration curve has enabled the production of high-precision reliable ages Sixty 14C-dated samples, originating from 19 pits and from depths ranging from 0.10 m to 4.20 m, have already provided an absolute time framework for the use of the cave. The earliest limit of human presence probably exceeds 48,000 BP and the latest reaches World War II. Within these limits the 14C dating of samples from consecutive layers, in combination with the archaeological data, permits the resolution of successive anthropogenic and environmental events.
    • The Copper Age in Northern Italy

      Zoppi, U.; Fulcheri, E.; Gambari, F. M.; Hua, Q.; Lawson, E. M.; Micheletti Cremasco, M.; Venturino Gambari, M. (Department of Geosciences, The University of Arizona, 2001-01-01)
      During the period between the IVth and IIIrd millennia BC, profound changes for the ancient populations inhabiting the northern region of Italy occurred. The first Indo-European migrations were altering the ethnographic characteristics and, with the production of the first copper artifacts, the Neolithic Age was drawing to an end. The most significant testimony of that dramatic period is unquestionably the Otztal iceman. In addition, many other valuable archaeological sites, such as Alba (Cuneo, Italy), have been discovered. Although Alba produced the oldest evidence of copper objects in a Neolithic context (5380 +/40 BP; GX-25859-AMS), more recent discoveries have underlined the importance of this archaeological site. In this paper we will report on a series of radiocarbon measurements of bone remnants which, combined with morphologic, stratigraphic, paleoanthropologic, and paleopathologic studies, have allowed us to gain new insights into the culture and chronology of the European Copper Age.
    • The Kennewick Skeleton: Chronological and Biomolecular Contexts

      Taylor, R. E.; Smith, David Glenn; Southon, John R. (Department of Geosciences, The University of Arizona, 2001-01-01)
      A human skeleton recovered near Kennewick, Washington, USA in 1996 has been dated to the early Holocene on the basis of multiple radiocarbon determinations, an analysis of a style of a temporally diagnostic projectile point found embedded in the ilium of the skeleton, and geological investigations of the locality where the skeleton was recovered. Based on morphological criteria, the Kennewick skeleton, which is one of the most complete early Holocene human skeletons recovered so far in the Western Hemisphere, appears to be more similar to those of modern South Asians and Europeans than to modern Native Americans or to contemporary indigenous populations of Northeast Asia.