• Late Holocene Climatic Change in the Balkans: Speleothem Isotopic Data from Serbia

      Kacanski, Aleksander; Carmi, Israel; Shemesh, Aldo; Kronfeld, Joel; Yam, Ruth; Flexer, Akiva (Department of Geosciences, The University of Arizona, 2001-01-01)
      A detailed profile of the stable isotopes of carbon and oxygen was obtained from a speleothem (stalagmite) from the Ceremosjna Cave in eastern Serbia. The stalagmite is a low magnesian calcite that did not show any evidence of diagenetic alteration. It was precipitated under isotopic equilibrium conditions from dripping water. The age and rate of deposition was derived from six internally consistent radiocarbon dates. The initial 14C activity was determined to be approximately 80 pMC. The stalagmite appears to preserve a continuous record of calcite deposition from approximately 2300 BP until the present. Oxygen isotopic data, based upon 100 samples, are used to derive the first paleotemperature record for Serbia. A regression analysis of the all the data indicates that over the period of time that the speleothem was deposited there was a general trend of lowering of the average temperature. Superimposed upon this are significant long-term temperature fluctuations. These can be divided into four broader climatic groupings. Going from the oldest times to the present, there are two warm periods separated by a period when the temperatures fell below the temperature trend line. However, the absolute temperatures were generally above those of the more recent period that is generally characterized by the coolest climatic conditions.
    • Major Recent Tectonic Uplift in Iskenderun Bay, Turkey

      Koral, H.; Kronfeld, J.; Avsar, N.; Yanko, V.; Vogel, J. C. (Department of Geosciences, The University of Arizona, 2001-01-01)
      Radiocarbon dating was carried out in the sediment profiles of four marine sediment cores taken from Iskenderun Bay, Turkey. The bay is quite shallow in the present day, and a previous tectonic study had considered that the bay floor might have been subsiding. However, this cannot be so, for the 14C ages would thereby lead to the apparent paradox of normal marine sedimentation having taken place during times when glacio-eustatic sea level lowering would have exposed the bay floor. Rather, we conclude that the floor of Iskenderun Bay on the whole has been experiencing rapid uplift since the end of the Last Glacial, due to a combination of tectonic factors linked to the compression between the Anatolian and African plates.
    • Measurement of Radiocarbon Content in Leaves from Some Japanese Sites

      Muraki, Yasushi; Masuda, Kimiaki; Arslanov, K.; Toyoizumi, Hiroaki; Kato, Masataka; Naruse, Yukiko; Murata, Takuya; Nishiyama, Tohru (Department of Geosciences, The University of Arizona, 2001-01-01)
      We have measured radiocarbon contents in leaves collected from 15 sites in Japan, including mountain areas and big city areas for last three years. Comparing the radiocarbon contents in various areas, high 14C concentrations (80-100‰ as δ14C) are seen for the leaves from the mountain and country sites. On the contrary, low concentrations (5-40‰) were observed for the leaves from city region, especially near the road with heavy traffic. These results indicate that the atmosphere of the mountain and country sites in Japan is still clean but the CO2 gas coming from fossil non-radioactive carbon significantly pollutes the atmosphere of the city sites. The value of δ14C for the mountain areas implies that 14C produced by nuclear bomb test in 1960s still remains. The decrease of δ14C at heavy traffic sites in Tokyo is consistent with the increase of CO2 concentration in the atmosphere assuming that almost all CO2 gas in this region originates from the fossil fuel.
    • New Chronological Frame for the Young Neolithic Baden Culture in Central Europe (4th Millennium BC)

      Wild, Eva Maria; Stadler, Peter; Bondár, Maria; Draxler, Susanne; Friesinger, Herwig; Kutschera, Walter; Priller, Alfred; Rom, Werner; Ruttkay, Elisabeth; Steier, Peter (Department of Geosciences, The University of Arizona, 2001-01-01)
      The Baden Culture is a widely spread culture of the Young Neolithics in east-central Europe. In southeast Europe, several parallel cultures are found at different places. The main innovations in east-central Europe associated with the Baden Culture were traditionally thought to originate in southeast Europe, Anatolia, and the Levant. However, in recent years, doubt about this theory has arisen among archaeologists. Here, we try to contribute to this question by increasing the radiocarbon data set available for the Baden Culture. Thirty-two age determinations of samples from different sites assigned to the Baden Culture were performed by accelerator mass spectrometry (AMS) 14C dating. The new data were combined with previously published 14C dates. Data from the individual cultural phases of the entire Baden period and the parallel cultures in southeast Europe (Sitagroi, Cernavoda, and Ezero) were analyzed by sum calibration. Comparison of the results indicates that the southeastern cultures cannot be synchronized with the Boleráz period, the early phase of the Baden Culture. It seems that these cultures were parallel to the Baden Classical period. This finding, which has to be verified by more data from the southeastern cultures, contradicts the theory of the east–west spreading of these cultures.
    • New Data on Chronology of Landscape-Paleoclimatic Stages in Northwestern Russia During the Late Glacial and Holocene

      Arslanov, Kh A.; Savelieva, L. A.; Klimanov, V. A.; Chernov, S. B.; Maksimov, F. E.; Tertychnaya, T. V.; Subetto, D. A. (Department of Geosciences, The University of Arizona, 2001-01-01)
      Two lake and bog sediments have been thoroughly studied using palynological and radiocarbon dating methods. These are the Lembolovskoye Lake section located in the southern part of the Karelian Ithmus and the Mshinskoye bog section located in the southwestern part of the Leningrad province. The data obtained allow us to reconstruct the main features of the vegetation cover evolution, the chronology for the appearance and a real distribution of the main arboreal species from the south of the Leningrad province to the north, and to construct curves of the paleoclimate parameter changes for the area under study. Thirty-six 14C dates were obtained for the Lembolovskoye Lake section (7 m thick). According to those dates, the organic gyttja formation in the lake began 9870 +/170 BP. Spore-pollen spectra with high percentage of herbs, arborescent, and shrub-birch dated back to the Younger Dryas were found out in clay layers at a depth of 6.5 m. An appearance of spruce and alder pollen is dated at 6860 +/120 and 7510 +/150 BP, respectively. The maximal percentage of broad-leaved species falls on the first half of the Atlantic (AT-1). Thirty-two dates were obtained for the Mshinskoye bog section (6 m thick): from 60 +/70 to 9520 +/170 BP (the last date fixed the beginning of peat formation); 12 palinozones from the Preboreal to the Subatlantic were recognized there. The spruce and alder pollen began to appear 7520 +/110 and 7670 +/130 BP, respectively. The maximal amount of broad-leaved species is observed at 4690 +/80 BP. The detailed reconstruction of changes in vegetation communities during the Late Glacial and Holocene was correlated with paleoclimatic characteristics, which have been reconstructed for the section under study by using the information from a statistical method of spore-pollen data processing.
    • New Radiocarbon Dates of the North Asian Steppe Zone and its Consequences for the Chronology

      Göersdorf, Jochen; Parzinger, Hermann; Nagler, Anatoli (Department of Geosciences, The University of Arizona, 2001-01-01)
      The chronological problems of the Steppe zone have been under intensive investigation during the last years but no generally accepted chronological system existed up to now. We present new radiocarbon dates of samples from several excavation sites. The dates allow a comparison of the Bronze Age development in the Siberian Steppe Zone with other neighboring regions.
    • Paleoenvironment in Dae-Am San High Moor in the Korean Peninsula

      Yoshioka, T.; Lee, J. Y.; Takahashi, H. A.; Kang, S. J. (Department of Geosciences, The University of Arizona, 2001-01-01)
      We discuss paleoenvironmental changes at the Dae-Am San high moor, located near the Demilitarized Zone at 38 degrees N. This area has been reported to be the only high moor in the Korean peninsula. The 14C age of the bottom sediment (75-80 cm in depth) at this site is about 1900 BP. Since the radiocarbon ages for the intervals at 50-55 cm and 75-80 cm were almost the same, we conclude that the deep layers (55-80 cm) in the high moor were all part of the original soil. Low organic C and N contents in the deeper layers support this inference. The 50-55 cm layer consists of sandy material with very low organic content, suggesting erosion from the surrounding area. The surface layer (0-5 cm) was measured as 190 BP, and the middle layer (30-35 cm) was 870 BP. The bulk sedimentation rate was estimated to be about 0.4 mm yr-1 for the 0-30-cm interval. The delta-13C value of organic carbon in the sediments fluctuated with depth. The delta-13C profile of the Dae-Am San high moor may be explained by climatic changes which occurred during the Little Ice Age and Medieval Warm Period.
    • 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).