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Sample records for ams radiocarbon dating

  1. AMS radiocarbon dating of ancient Japanese sutras

    CERN Document Server

    Oda, H; Nakamura, T; Fujita, K

    2000-01-01

    Radiocarbon ages of ancient Japanese sutras whose historical ages were known paleographically were measured by means of accelerator mass spectrometry (AMS). Calibrated radiocarbon ages of five samples were consistent with the corresponding historical ages; the 'old wood effect' is negligible for ancient Japanese sutras. Japanese paper has been made from fresh branches grown within a few years and the interval from trimming off the branches to writing sutra on the paper is within one year. The good agreement between the calibrated radiocarbon ages and the historical ages is supported by such characteristics of Japanese paper. It is indicated in this study that Japanese sutra is a suitable sample for radiocarbon dating in the historic period because of little gap by 'old wood effect'.

  2. AMS radiocarbon dating of cemetery of Jin Marquises in China

    CERN Document Server

    Wu, X; Wang, J; Guo, Z; Liu, K; Lü, X; Ma, H; Li, K; Yuan, J; Cai, L

    2000-01-01

    Bones are very important samples to determine the hosts of the cemetery of Jin Marquises which were excavated at Tianma-Qucun site in Shanxi Province in China. In order to obtain accurate AMS radiocarbon dates, bones were pretreated by two kinds of methods, the gelatin-extraction method and the amino-acid method. Charcoals collected from the same sites were also used. The measured dates agree with historical record.

  3. AMS radiocarbon dating of very large Grandidier's baobabs (Adansonia grandidieri)

    Science.gov (United States)

    Patrut, Adrian; von Reden, Karl F.; Danthu, Pascal; Leong Pock-Tsy, Jean-Michel; Rakosy, Laszlo; Patrut, Roxana T.; Lowy, Daniel A.; Margineanu, Dragos

    2015-10-01

    The article reports the AMS radiocarbon investigation of the two largest known Adansonia grandidieri specimens. The two baobabs, which are named Tsitakakoike and Pregnant baobab, are located in Southwestern Madagascar, near Andombiro. A third specimen from this area, the House baobab, was also investigated. According to measurements, Tsitakakoike is the biggest individual above ground level of all Adansonia species. The House baobab was selected for its exposed structure, which is identical to the closed ring-shaped structure with false cavities identified by us in large and old Adansonia digitata specimens. According to our research, Tsitakakoike and the Pregnant baobab have multi-stemmed cylindrical trunks which are mainly hollow; the two very large baobabs also possess a ring-shaped structure. The radiocarbon dates of the oldest wood samples collected from the large trunks were 1274 ± 20 BP for Tsitakakoike and 930 ± 20 BP for the Pregnant baobab. According to their original positions and to the architectures of the two A. grandidieri, the ages of Tsitakakoike and Pregnant baobab would be between 1300 and 1500 years. Therefore, A. grandidieri becomes the third Adansonia species with individuals that can live over 1000 years, according to accurate dating results.

  4. Radiocarbon Dating

    Energy Technology Data Exchange (ETDEWEB)

    Buchholz, B A

    2007-12-20

    Radiocarbon dating can be used to determine the age of objects that contain components that were once alive. In the case of human remains, a radiocarbon date can distinguish between a crime scene and an archeological site. Documents, museum artifacts and art objects can be dated to determine if their age is correct for the historical context. A radiocarbon date does not confirm authenticity, but it can help identify a forgery.

  5. AMS radiocarbon dating on Campos Basin, Southeast Brazilian Continental Slope

    Energy Technology Data Exchange (ETDEWEB)

    Macario, K.D.; Anjos, R.M.; Gomes, P.R.S. E-mail: paulogom@if.uff.br; Figueiredo, A.G.; Lacerda de Souza, C.; Barbosa, C.F.; Coimbra, M.M.; Elmore, D

    2004-08-01

    We present results on radiocarbon dating of foraminifera shell samples, collected on the upper slope of Campos Basin, in Southern Brazil. This is the first time that the sedimentation rate of this area is measured with a fine scale (cm) stratigraphy. {sup 14}C ages vary from (2560 {+-} 80) years. BP at the top to (7260 {+-} 80) years. BP at the bottom of the sediment column. The mean accumulation ratio for the whole column is (6.2 {+-} 0.7) cm/kyears.

  6. Comparative AMS radiocarbon dating of pretreated versus non-pretreated tropical wood samples

    Energy Technology Data Exchange (ETDEWEB)

    Patrut, Adrian [Department of Chemistry, Babes-Bolyai University, 400028 Cluj-Napoca (Romania); Reden, Karl F. von, E-mail: kvonreden@whoi.ed [NOSAMS Facility, Department of Geology and Geophysics, Woods Hole Oceanographic Institution, Woods Hole, MA 02543 (United States); Lowy, Daniel A. [Nova Research Inc., Alexandria, VA 22308 (United States); Mayne, Diana H. [Baobab Trust, P.O. Box 1566, Parklands 2121, Johannesburg (South Africa); Elder, Kathryn E.; Roberts, Mark L.; McNichol, Ann P. [NOSAMS Facility, Department of Geology and Geophysics, Woods Hole Oceanographic Institution, Woods Hole, MA 02543 (United States)

    2010-04-15

    Several wood samples collected from Dorslandboom, a large iconic African baobab (Adansonia digitata L.) from Namibia, were investigated by AMS radiocarbon dating subsequent to pretreatment and, alternatively, without pretreatment. The comparative statistical evaluation of results showed that there were no significant differences between fraction modern values and radiocarbon dates of the samples analyzed after pretreatment and without pretreatment, respectively. The radiocarbon date of the oldest sample was 993 +- 20 BP. Dating results also revealed that Dorslandboom is a multi-generation tree, with several stems showing different ages.

  7. Comparative AMS radiocarbon dating of pretreated versus non-pretreated tropical wood samples

    Science.gov (United States)

    Patrut, Adrian; von Reden, Karl F.; Lowy, Daniel A.; Mayne, Diana H.; Elder, Kathryn E.; Roberts, Mark L.; McNichol, Ann P.

    2010-04-01

    Several wood samples collected from Dorslandboom, a large iconic African baobab ( Adansonia digitata L.) from Namibia, were investigated by AMS radiocarbon dating subsequent to pretreatment and, alternatively, without pretreatment. The comparative statistical evaluation of results showed that there were no significant differences between fraction modern values and radiocarbon dates of the samples analyzed after pretreatment and without pretreatment, respectively. The radiocarbon date of the oldest sample was 993 ± 20 BP. Dating results also revealed that Dorslandboom is a multi-generation tree, with several stems showing different ages.

  8. The use of AMS radiocarbon dating for Xia-Shang-Zhou chronology

    CERN Document Server

    Guo, Z Y; LiuKeXin; Lu Xiang Yang; Ma Hong Ji; Wu Xiao Hon; Yuan Si Xun

    2000-01-01

    The possibility and problems of using radiocarbon dating to historical chronology are discussed. The current situation of ancient Chinese chronology and the project of Xia-Shang-Zhou chronology are introduced. A chronological study requires the AMS radiocarbon dating with high precision, high reliability and high efficiency. The Peking University AMS facility (PKUAMS) has been upgraded and a series of quality control steps were adopted. To reduce the error of calendar age, wiggle matching with serial samples should be used. Some preliminary results of Xia-Shang-Zhou chronology are presented.

  9. Preliminary study on radiocarbon AMS dating of pollen

    Institute of Scientific and Technical Information of China (English)

    周卫建; 周杰; 萧家仪; D.Donahue; A.J.T.Jull

    1999-01-01

    17 samples were collected from aeolian and lacustrine profiles within the environment sensitive zone of the Loess Plateau, and an experimental method was established which is suitable for pollen extraction from aeolian sediment. A comparative study of pollen dating was carried out using the accelerator mass spectrometry (AMS) 14C dating of known age samples, and then an experiment with the pollen concentrates was performed. The results indicate that pollen that has been deposited simultaneously with sediment in a stable environment can provide reliable ages. This technique will provide a way of improving the chronological framework for the Loess Plateau since the late Pleistocene. The 14C dating was combined with field investigations, and from the geological record within this zone, evidence was extracted of four major monsoon precipitation changes during the transition from the late Pleistocene to Holoeene.

  10. Old ages of two historical Romanian trees assessed by AMS radiocarbon dating

    Energy Technology Data Exchange (ETDEWEB)

    Patrut, Adrian, E-mail: apatrut@gmail.com [Babes-Bolyai University, Department of Chemistry, Arany Janos 11, 400028 Cluj-Napoca (Romania); Reden, Karl F. von [Woods Hole Oceanographic Institution, Department of Geology and Geophysics, NOSAMS Facility, 360 Woods Hole Rd., Mailstop 8, Woods Hole, MA 02543 (United States); Lowy, Daniel A. [FlexEl, LLC, 387 Technology Drive, College Park, MD 20742 (United States); Patrut, Roxana T. [Babes-Bolyai University, Department of Biology and Geology, Gh. Bilascu 44, 400015 Cluj-Napoca (Romania); Lucian Vaida, D. [Museum of Border Regiment Nasaud, Granicerilor 19, 425200 Nasaud (Romania); Margineanu, Dragos [Babes-Bolyai University, Department of Chemistry, Arany Janos 11, 400028 Cluj-Napoca (Romania)

    2013-01-15

    Two large Romanian poplars are considered to be associated with significant historical events of the past. In order to verify these claims, wood samples collected from the broken trunks of the two poplars were radiocarbon dated by AMS. The oldest radiocarbon dates were found to be 275 {+-} 20 bp for the black poplar of Mocod and 316 {+-} 22 bp for the gray poplar of Rafaila. These values correspond to calibrated ages of 365 {+-} 10 and 465 {+-} 25 years, respectively. The dating results indicate old ages for the two trees, i.e., 455 years for the Mocod poplar and 560 years for the Rafaila poplar. Such age values validate historical information on the two large Romanian trees.

  11. AMS radiocarbon dating of mortar: The case study of the medieval UNESCO site of Modena

    Energy Technology Data Exchange (ETDEWEB)

    Carmine, Lubritto [Dipartimento di Scienze e Tecnologie Ambientali, Biologiche e Farmaceutiche & CIRCE lab, Seconda Università degli Studi di Napoli, I-81100 Caserta (Italy); Caroselli, Marta; Lugli, Stefano [Dipartimento di Scienze Chimiche e Geologiche, Università di Modena e Reggio Emilia, I-41100 Modena (Italy); Marzaioli, Fabio [Dipartimento di Matematica e Fisica & CIRCE lab, Seconda Università degli Studi di Napoli, I-81100 Caserta (Italy); Nonni, Sara [Università degli Studi “Sapienza”, Dipartimento di Scienze della Terra, I-00185 Roma (Italy); Marchetti Dori, S. [Dipartimento di Scienze Chimiche e Geologiche, Università di Modena e Reggio Emilia, I-41100 Modena (Italy); Terrasi, Filippo [Dipartimento di Matematica e Fisica & CIRCE lab, Seconda Università degli Studi di Napoli, I-81100 Caserta (Italy)

    2015-10-15

    The carbon dioxide contributing to binder formation during the set of a lime mortar reflects the atmospheric {sup 14}C content at the time of construction of a building. For this reason, the {sup 14}C dating of mortars is used with increasing frequencies in archaeological and architectural research. Mortars, however, may also contain carbonaceous contaminants potentially affecting radiocarbon dating. The Centre for Isotopic Research on Cultural and Environmental heritage (CIRCE) of the Second University of Naples (SUN) has recently obtained some promising results in mortar radiocarbon dating thanks to the development of a procedure (i.e. CryoSoniC/Cryo2SoniC) aiming to eliminate exogenous C contamination that may occur in a mortar. The construction history of the UNESCO World Heritage Site of Modena (Italy) is still controversial and represents a challenging case study for the application of absolute dating methodologies for different reasons. From the point of view of {sup 14}C dating, for example, given the high percentage of carbonate aggregates composing these samples, Modena mortars represent an experimental test particularly indicative of exogenous carbon sources suppression ensuring methodology accuracy. In this paper several AMS Radiocarbon dates were carried out on lime lumps with the aim to: (i) verify procedure accuracy by a comparison of the results obtainable from lime lumps dated after different treatments (i.e. bulk lime lumps vs. CryoSoniC purified lime lumps); (ii) compare different building phases absolute chronology for the medieval UNESCO site of Modena, with that assumed by historical sources in order to assess preliminary the {sup 14}C dating feasibility for of the site. Historical temporal constraints and mortar clustering, based on petrography, have been applied to define a temporal framework of the analyzed structure. Moreover, a detailed petrographic characterization of mortars was used both as a preliminary tool for the choice of samples

  12. AMS Radiocarbon Dating of Large Za Baobabs (Adansonia za) of Madagascar.

    Science.gov (United States)

    Patrut, Adrian; Patrut, Roxana T; Danthu, Pascal; Leong Pock-Tsy, Jean-Michel; Rakosy, Laszlo; Lowy, Daniel A; von Reden, Karl F

    2016-01-01

    The article reports the radiocarbon investigation of Anzapalivoro, the largest za baobab (Adansonia za) specimen of Madagascar and of another za, namely the Big cistern baobab. Several wood samples collected from the large inner cavity and from the outer part/exterior of the tree were investigated by AMS (accelerator mass spectrometry) radiocarbon dating. For samples collected from the cavity walls, the age values increase with the distance into the wood up to a point of maximum age, after which the values decrease toward the outer part. This anomaly of age sequences indicates that the inner cavity of Anzapalivoro is a false cavity, practically an empty space between several fused stems disposed in a ring-shaped structure. The radiocarbon date of the oldest sample was 780 ± 30 bp, which corresponds to a calibrated age of around 735 yr. Dating results indicate that Anzapalivoro has a closed ring-shaped structure, which consists of 5 fused stems that close a false cavity. The oldest part of the biggest za baobab has a calculated age of 900 years. We also disclose results of the investigation of a second za baobab, the Big cistern baobab, which was hollowed out for water storage. This specimen, which consists of 4 fused stems, was found to be around 260 years old.

  13. AMS Radiocarbon Dating of Large Za Baobabs (Adansonia za of Madagascar.

    Directory of Open Access Journals (Sweden)

    Adrian Patrut

    Full Text Available The article reports the radiocarbon investigation of Anzapalivoro, the largest za baobab (Adansonia za specimen of Madagascar and of another za, namely the Big cistern baobab. Several wood samples collected from the large inner cavity and from the outer part/exterior of the tree were investigated by AMS (accelerator mass spectrometry radiocarbon dating. For samples collected from the cavity walls, the age values increase with the distance into the wood up to a point of maximum age, after which the values decrease toward the outer part. This anomaly of age sequences indicates that the inner cavity of Anzapalivoro is a false cavity, practically an empty space between several fused stems disposed in a ring-shaped structure. The radiocarbon date of the oldest sample was 780 ± 30 bp, which corresponds to a calibrated age of around 735 yr. Dating results indicate that Anzapalivoro has a closed ring-shaped structure, which consists of 5 fused stems that close a false cavity. The oldest part of the biggest za baobab has a calculated age of 900 years. We also disclose results of the investigation of a second za baobab, the Big cistern baobab, which was hollowed out for water storage. This specimen, which consists of 4 fused stems, was found to be around 260 years old.

  14. AMS radiocarbon dating of very large Grandidier’s baobabs (Adansonia grandidieri)

    Energy Technology Data Exchange (ETDEWEB)

    Patrut, Adrian [Babeş-Bolyai University, Faculty of Chemistry, Cluj-Napoca (Romania); Reden, Karl F. von [NOSAMS Facility, Dept. of Geology & Geophysics, Woods Hole Oceanographic Institution, Woods Hole, MA (United States); Danthu, Pascal [Cirad, UPR BSEF, Montpellier (France); DP Forêt et Biodiversité, Antananarivo (Madagascar); Leong Pock-Tsy, Jean-Michel [DP Forêt et Biodiversité, Antananarivo (Madagascar); Rakosy, Laszlo; Patrut, Roxana T. [Babeş-Bolyai University, Faculty of Biology and Geology, Cluj-Napoca (Romania); Lowy, Daniel A. [Nova University, Alexandria Campus, Alexandria, VA (United States); Margineanu, Dragos [Babeş-Bolyai University, Faculty of Chemistry, Cluj-Napoca (Romania)

    2015-10-15

    The article reports the AMS radiocarbon investigation of the two largest known Adansonia grandidieri specimens. The two baobabs, which are named Tsitakakoike and Pregnant baobab, are located in Southwestern Madagascar, near Andombiro. A third specimen from this area, the House baobab, was also investigated. According to measurements, Tsitakakoike is the biggest individual above ground level of all Adansonia species. The House baobab was selected for its exposed structure, which is identical to the closed ring-shaped structure with false cavities identified by us in large and old Adansonia digitata specimens. According to our research, Tsitakakoike and the Pregnant baobab have multi-stemmed cylindrical trunks which are mainly hollow; the two very large baobabs also possess a ring-shaped structure. The radiocarbon dates of the oldest wood samples collected from the large trunks were 1274 ± 20 BP for Tsitakakoike and 930 ± 20 BP for the Pregnant baobab. According to their original positions and to the architectures of the two A. grandidieri, the ages of Tsitakakoike and Pregnant baobab would be between 1300 and 1500 years. Therefore, A. grandidieri becomes the third Adansonia species with individuals that can live over 1000 years, according to accurate dating results.

  15. AMS radiocarbon dating of pollen concentrates in a karstic lake system

    Science.gov (United States)

    Fletcher, William; Zielhofer, Christoph; Mischke, Steffen; Campbell, Jennifer; Bryant, Charlotte; Fink, David; Xu, Xiaomei

    2016-04-01

    In lake sediments where terrestrial macrofossils are rare or absent, AMS radiocarbon dating of pollen concentrates represents an important alternative solution for developing a robust and high resolution chronology suitable for Bayesian modelling of age-depth relationships. Here we report an application of the dense media separation approach (Vandergoes and Prior, Radiocarbon 45:479-492, 2003) to Holocene lake sediments from karstic Lake Sidi Ali, Morocco (33° 03'N, 05° 00'W; 2,080 m a.s.l.). Paired dates on terrestrial (macrofossil) and aquatic (ostracod) samples, and dating of bulk sediment surface material at the site indicate varying reservoir effects of up to 900 yr and highlight the need to date terrestrial carbon sources. Dating of pollen concentrates is a viable approach at Lake Sidi Ali, as pollen concentrations are high (~200,000 grains/cc), and pollen assemblages typically contain only minor percentages (standards (anthracite, IAEA C5 wood) were prepared and dated following the heavy liquid (sodium polytungstate, SPT) density separation protocol. A series of SPT solutions of progressively decreasing density (1.9-1.15 s.g.) were used to divide the samples into several fractions. The pollen purity of these fractions was evaluated by microscopic analysis of smear slides, and the richest fraction(s) were selected for dating. Sieving at 10 μm and at 50/125 μm (depending on the size of predominant pollen grains) was used to further concentrate the pollen grains, and the samples were freeze dried to determine the dry weight of material. The results show that the highest purity of pollen is sample dependent and may typically be achieved in the fractions precipitating at 1.4-1.2 s.g. With sieving, terrestrial pollen purity of ~50-80% can be achieved, offering a considerable improvement in terms of terrestrial carbon content over bulk sediment. These values reflect the challenge in some samples of fully separating pollen grains from common aquatic algae, e

  16. A reevaluation of the Pallett Creek earthquake chronology based on new AMS radiocarbon dates, San Andreas fault, California

    Science.gov (United States)

    Scharer, K.M.; Biasi, G.P.; Weldon, R.J.

    2011-01-01

    The Pallett Creek paleoseismic record occupies a keystone position in most attempts to develop rupture histories for the southern San Andreas fault. Previous estimates of earthquake ages at Pallett Creek were determined by decay counting radiocarbon methods. That method requires large samples which can lead to unaccounted sources of uncertainty in radiocarbon ages because of the heterogeneous composition of organic layers. In contrast, accelerator mass spectrometry (AMS) radiocarbon dates may be obtained from small samples that have known carbon sources and also allow for a more complete sampling of the section. We present 65 new AMS radiocarbon dates that span nine ground-rupturing earthquakes at Pallett Creek. Overall, the AMS dates are similar to and reveal no dramatic bias in the conventional dates. For many layers, however, individual charcoal samples were younger than the conventional dates, leading to earthquake ages that are overall slightly younger than previously reported. New earthquake ages are determined by Bayesian refinement of the layer ages based on stratigraphic ordering and sedimentological constraints. The new chronology is more regular than previously published records in large part due to new samples constraining the age of event R. The closed interval from event C to 1857 has a mean recurrence of 135years (?? = 83.2 years) and a quasiperiodic coefficient of variation (COV) of 0.61. We show that the new dates and resultant earthquake chronology have a stronger effect on COV than the specific membership of this long series and dating precision improvements from sedimentation rates. Copyright 2011 by the American Geophysical Union.

  17. 'Wiggle matching' radiocarbon dates

    NARCIS (Netherlands)

    Ramsey, CB; van der Plicht, J; Weninger, B

    2001-01-01

    This paper covers three different methods of matching radiocarbon dates to the 'wiggles' of the calibration curve in those situations where the age difference between the C-14 dates is known. These methods are most often applied to tree-ring sequences. The simplest approach is to use a classical Chi

  18. Radiocarbon Dating the Anthropocene

    Science.gov (United States)

    Chaput, M. A.; Gajewski, K. J.

    2015-12-01

    The Anthropocene has no agreed start date since current suggestions for its beginning range from Pre-Industrial times to the Industrial Revolution, and from the mid-twentieth century to the future. To set the boundary of the Anthropocene in geological time, we must first understand when, how and to what extent humans began altering the Earth system. One aspect of this involves reconstructing the effects of prehistoric human activity on the physical landscape. However, for global reconstructions of land use and land cover change to be more accurately interpreted in the context of human interaction with the landscape, large-scale spatio-temporal demographic changes in prehistoric populations must be known. Estimates of the relative number of prehistoric humans in different regions of the world and at different moments in time are needed. To this end, we analyze a dataset of radiocarbon dates from the Canadian Archaeological Radiocarbon Database (CARD), the Palaeolithic Database of Europe and the AustArch Database of Australia, as well as published dates from South America. This is the first time such a large quantity of dates (approximately 60,000) has been mapped and studied at a global scale. Initial results from the analysis of temporal frequency distributions of calibrated radiocarbon dates, assumed to be proportional to population density, will be discussed. The utility of radiocarbon dates in studies of the Anthropocene will be evaluated and potential links between population density and changes in atmospheric greenhouse gas concentrations, climate, migration patterning and fire frequency coincidence will be considered.

  19. Radiocarbon dating of ancient Japanese documents

    Energy Technology Data Exchange (ETDEWEB)

    Oda, H. [Nagoya Univ., Center for Chronological Research, Nagoya, Aichi (Japan)

    2001-06-01

    History is a reconstruction of past human activity, evidence of which is remained in the form of documents or relics. For the reconstruction of historic period, the radiocarbon dating of ancient documents provides important information. Although radiocarbon age is converted into calendar age with the calibration curve, the calibrated radiocarbon age is still different from the historical age when the document was written. The difference is known as 'old wood effect' for wooden cultural property. The discrepancy becomes more serious problem for recent sample which requires more accurate age determination. Using Tandetron accelerator mass spectrometer at Nagoya University, we have measured radiocarbon ages of Japanese ancient documents, sutras and printed books written dates of which are clarified from the paleographic standpoint. The purpose is to clarify the relation between calibrated radiocarbon age and historical age of ancient Japanese document by AMS radiocarbon dating. This paper reports 23 radiocarbon ages of ancient Japanese documents, sutras and printed books. The calibrated radiocarbon ages are in good agreement with the corresponding historical ages. It was shown by radiocarbon dating of the ancient documents that Japanese paper has little gap by 'old wood effect'; accordingly, ancient Japanese paper is a suitable sample for radiocarbon dating of recent historic period. (author)

  20. Peat record reflecting Holocene climatic change in the Zoige Plateau and AMS radiocarbon dating

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Through the use of reliable AMS dating of high resolution (15-30 years) peat and the establishment of monsoon climate proxies sequence, we have been able to recognize several cold, dry events in the Tibetan Plateau during the Holocene. The more obvious ones occurred around 12800, 11300, 10200, 9580, 8900, 6400, 4400, 3700, 2800 and 1500 cal. aBP. These events correlate well with both ice rafting events recorded in high latitude North Atlantic Ocean sediment cores and cooling events in the low latitude SST. Spectral analysis indicates high frequency climate variation on centennial-millennial time scale during the Holocene. This further reflects Holocene climate instability and the existence of centennial-millenium scale rhythm in mid latitude areas as well.

  1. Vulcanism and Radiocarbon Dates

    Science.gov (United States)

    Libby, L. M.; Libby, W. F.

    1972-10-01

    We consider whether the long term perturbation of radiocarbon dates, which is known to be approximately a sin function of period about 8000 years and amplitude of about 8% peak-to-peak, could have been caused in any major part by vulcanism. We conclude that this is not the case. On the contrary, present day volcanoes are a far less important source of inert CO{sub 2} (about 100 fold less) than is man's burning of fossil fuels which has caused the Suess dilution of about 2%. (auth)

  2. Microscale radiocarbon dating of paintings

    Energy Technology Data Exchange (ETDEWEB)

    Hendriks, Laura; Hajdas, Irka; McIntyre, Cameron [ETH Zurich, Ion Beam Physics, Zurich (Switzerland); Kueffner, Markus; Ferreira, Ester S.B. [SIK-ISEA, Zurich, Zurich (Switzerland); Scherrer, Nadim C. [Bern University of Applied Sciences, HKB, Bern (Switzerland)

    2016-03-15

    In this paper, radiocarbon dating of paintings using minimal sample sizes has been investigated, in an effort to address the problem of limited access to sample material in paintings. {sup 14}C analyses were conducted on signed and dated paintings from two Swiss artists of the twentieth century. The selected paintings dated from the 1930s and 1960s, provided the opportunity to evaluate the dating accuracy on paintings realized before and after 1950 AD when the {sup 14}C bomb peak was created, as a result of the nuclear tests conducted in the 1950/1960s. The work focused on the one hand on minimizing the size of the canvas sample required for accelerator mass spectrometer radiocarbon measurement on the gas ion source of the MICADAS and, on the other hand, on testing the possibility of dating the organic binder of the paint. Following careful characterization of the paint composition by X-ray fluorescence spectroscopy, Fourier transformed infrared spectroscopy, and Raman spectroscopy, paints containing no other carbon source than the natural organic binder were identified and dated. (orig.)

  3. Microscale radiocarbon dating of paintings

    Science.gov (United States)

    Hendriks, Laura; Hajdas, Irka; McIntyre, Cameron; Küffner, Markus; Scherrer, Nadim C.; Ferreira, Ester S. B.

    2016-03-01

    In this paper, radiocarbon dating of paintings using minimal sample sizes has been investigated, in an effort to address the problem of limited access to sample material in paintings. 14C analyses were conducted on signed and dated paintings from two Swiss artists of the twentieth century. The selected paintings dated from the 1930s and 1960s, provided the opportunity to evaluate the dating accuracy on paintings realized before and after 1950 AD when the 14C bomb peak was created, as a result of the nuclear tests conducted in the 1950/1960s. The work focused on the one hand on minimizing the size of the canvas sample required for accelerator mass spectrometer radiocarbon measurement on the gas ion source of the MICADAS and, on the other hand, on testing the possibility of dating the organic binder of the paint. Following careful characterization of the paint composition by X-ray fluorescence spectroscopy, Fourier transformed infrared spectroscopy, and Raman spectroscopy, paints containing no other carbon source than the natural organic binder were identified and dated.

  4. AMS radiocarbon dating of wood trunks in the pumiceous deposits of the Kikai-Akahoya eruption in Yakushima Island, SW Japan

    Energy Technology Data Exchange (ETDEWEB)

    Okuno, Mitsuru, E-mail: okuno@fukuoka-u.ac.jp [Department of Earth System Science, Faculty of Science, Fukuoka University, 814-0180 Fukuoka (Japan); AIG Collaborative Research Institute for International Study on Eruptive History and Informatics, Fukuoka University, 814-0180 Fukuoka (Japan); Nakamura, Toshio [Center for Chronological Research, Nagoya University, 464-8602 Nagoya (Japan); Geshi, Nobuo [Geological Survey of Japan, National Institute of Advanced Science and Technology, 305-8567 Tsukuba (Japan); Kimura, Katsuhiko [Division of Environment System Management, Faculty of Symbiotic System Science, Fukushima University, 960-1296 Fukushima (Japan); Saito-Kokubu, Yoko [Tono Geoscience Center, Japan Atomic Energy Agency (JAEA), 959-31 Jorinji, Toki, Gifu 509-5102 (Japan); Kobayashi, Tetsuo [Department of Earth and Environmental Sciences, Graduate School of Science and Engineering, Kagoshima University, 890-0065 Kagoshima (Japan)

    2013-01-15

    Radiocarbon dating using accelerator mass spectrometry (AMS) was performed on numerous wood trunks from pumiceous deposits along the Nagata, Isso and Miyanoura rivers on the northern side of Yakushima Island, 60 km south of Kyushu Island. The obtained {sup 14}C dates were around 6.5 ka BP, which, in combination with the geological characteristics of the pumiceous deposits indicates that these specimens were buried during the Kikai-Akahoya (K-Ah) eruption from the Kikai caldera. However, the fact that they are not charred suggests that the origin of these deposits are not pyroclastic flows. Fourteen taxa (Pinus subgen. Diploxylon, Tsuga, Cryptomeria, Chamaecyparis, Myrica, Castanea, Castanopsis, Quercus subgen. Cyclobalanopsis, Trochodendron, Phellodendron, Lagerstroemia, Rhododendron, Myrsine and Symplocos) were identified through anatomical characteristics. This is the first discovery of forest species on the Yakushima Island before the devastating eruption.

  5. AMS radiocarbon dating of wood trunks in the pumiceous deposits of the Kikai-Akahoya eruption in Yakushima Island, SW Japan

    Science.gov (United States)

    Okuno, Mitsuru; Nakamura, Toshio; Geshi, Nobuo; Kimura, Katsuhiko; Saito-Kokubu, Yoko; Kobayashi, Tetsuo

    2013-01-01

    Radiocarbon dating using accelerator mass spectrometry (AMS) was performed on numerous wood trunks from pumiceous deposits along the Nagata, Isso and Miyanoura rivers on the northern side of Yakushima Island, 60 km south of Kyushu Island. The obtained 14C dates were around 6.5 ka BP, which, in combination with the geological characteristics of the pumiceous deposits indicates that these specimens were buried during the Kikai-Akahoya (K-Ah) eruption from the Kikai caldera. However, the fact that they are not charred suggests that the origin of these deposits are not pyroclastic flows. Fourteen taxa (Pinus subgen. Diploxylon, Tsuga, Cryptomeria, Chamaecyparis, Myrica, Castanea, Castanopsis, Quercus subgen. Cyclobalanopsis, Trochodendron, Phellodendron, Lagerstroemia, Rhododendron, Myrsine and Symplocos) were identified through anatomical characteristics. This is the first discovery of forest species on the Yakushima Island before the devastating eruption.

  6. Radiocarbon dating of terrestrial carbonates

    Science.gov (United States)

    Pigati, Jeffrey S.; Rink, W. Jack; Thompson, Jeroen

    2014-01-01

    Terrestrial carbonates encompass a wide range of materials that potentially could be used for radiocarbon (14C) dating. Biogenic carbonates, including shells and tests of terrestrial and aquatic gastropods, bivalves, ostracodes, and foraminifera, are preserved in a variety of late Quaternary deposits and may be suitable for 14C dating. Primary calcareous deposits (marls, tufa, speleothems) and secondary carbonates (rhizoliths, fracture fill, soil carbonate) may also be targeted for dating when conditions are favorable. This chapter discusses issues that are commonly encountered in 14C dating of terrestrial carbonates, including isotopic disequilibrium and open-system behavior, as well as methods used to determine the reliability of ages derived from these materials. Recent methodological advancements that may improve the accuracy and precision of 14C ages of terrestrial carbonates are also highlighted.

  7. Increasing the dynamic range of radiocarbon AMS

    Energy Technology Data Exchange (ETDEWEB)

    Schulze-Koenig, Tim; Synal, Hans-Arno [Ion Beam Physics, ETH Zurich (Switzerland); Giacomo, Jason; Vogel, John [Vitalea Science, Davis, CA (United States)

    2009-07-01

    Whereas in radiocarbon dating efforts are done to minimize the background of an accelerator mass spectrometry (AMS) measurement, biomedical applications rather ask for an extension of the dynamic range on the upper end of the scale. Especially in the beginning of a {sup 14}C-tracer study, samples may have {sup 14}C/{sup 12}C ratios of up to 1000 fraction Modern Carbon (fMC). In a routine measurement procedure, those high ratios typically cause count rates of up to 100 kHz. Thus a detailed study of the detection system and its dead times becomes necessary. General considerations on dead times in detection systems as well as an analysis of the BioMICADAS detection system will be presented.

  8. Origins of the Iberomaurusian in NW Africa: new AMS radiocarbon dating of the Middle and Later Stone Age deposits at Taforalt Cave, Morocco.

    Science.gov (United States)

    Barton, R N E; Bouzouggar, A; Hogue, J T; Lee, S; Collcutt, S N; Ditchfield, P

    2013-09-01

    Recent genetic studies based on the distribution of mtDNA of haplogroup U6 have led to subtly different theories regarding the arrival of modern human populations in North Africa. One proposes that groups of the proto-U6 lineage spread from the Near East to North Africa around 40-45 ka (thousands of years ago), followed by some degree of regional continuity. Another envisages a westward human migration from the Near East, followed by further demographic expansion at ∼22 ka centred on the Maghreb and associated with a microlithic bladelet culture known as the Iberomaurusian. In evaluating these theories, we report on the results of new work on the Middle (MSA) and Later Stone (LSA) Age deposits at Taforalt Cave in Morocco. We present 54 AMS radiocarbon dates on bone and charcoals from a sequence of late MSA and LSA occupation levels of the cave. Using Bayesian modelling we show that an MSA non-Levallois flake industry was present until ∼24.5 ka Cal BP (calibrated years before present), followed by a gap in occupation and the subsequent appearance of an LSA Iberomaurusian industry from at least 21,160 Cal BP. The new dating offers fresh light on theories of continuity versus replacement of populations as presented by the genetic evidence. We examine the implications of these data for interpreting the first appearance of the LSA in the Maghreb and providing comparisons with other dated early blade and bladelet industries in North Africa.

  9. Radiocarbon dating of medieval manuscripts from the University of Seville

    Energy Technology Data Exchange (ETDEWEB)

    Santos, F.J., E-mail: fsantos@us.e [Centro Nacional de Aceleradores (CNA), Avda. Thomas Alva Edison 7, Isla de la Cartuja, 41092 Seville (Spain); Gomez-Martinez, I.; Garcia-Leon, M. [Centro Nacional de Aceleradores (CNA), Avda. Thomas Alva Edison 7, Isla de la Cartuja, 41092 Seville (Spain)

    2010-04-15

    Eleven samples (parchment and paper) from different medieval manuscripts belonging to the cultural heritage of the University of Seville have been radiocarbon dated on the 1 MV AMS facility at the CNA in Seville (Spain). The objective of this study is double. First of all, these are the first real 'unknown' samples treated in the radiocarbon laboratory and dated on our AMS facility, SARA (Spanish Accelerator for Radionuclide Analysis). Besides, some useful information about the manuscripts can be obtained, either to corroborate the dates, or in some cases, to decide between possible dates. As expected, a general agreement is found between radiocarbon results and palaeographical data. Nevertheless, some interesting facts have been learned through this study. We present in this paper the procedure to prepare the samples and the ages obtained with a brief discussion of the results.

  10. AMS radiocarbon dating at Oxford and its contribution to issues of the extinction of Neanderthals and the spread of Homo sapiens sapiens across Eurasia

    CERN Document Server

    Pettitt, P B; Hedges, R E M; Hodgins, G W L

    2000-01-01

    The Oxford Radiocarbon Accelerator Unit has participated in a number of projects central to the question of the evolutionary fate of the Neanderthals and the spread of our own species across Eurasia. This paper outlines some of the key issues in this field and reports on some dating projects which have refined our knowledge of these momentous events in human history.

  11. Time range for accumulation of shell middens from Higashimyo (western Japan) and Kimhae (southern Korea) by AMS radiocarbon dating

    Energy Technology Data Exchange (ETDEWEB)

    Nakamura, Toshio, E-mail: nakamura@nendai.nagoya-u.ac.jp [Center for Chronological Research, Nagoya University, Chikusa, Nagoya 464-8602 (Japan); Matsui, Akira [National Research Institute for Cultural Properties, Nara, Nijyo-cho, Nara 630-8577 (Japan); Nishida, Iwao; Nakano, Mitsuru [Saga-City Board of Education, Sakae-machi, Saga 840-8501 (Japan); Omori, Takayuki [University Museum, University of Tokyo, Hongo 7-3-1, Bunkyo, Tokyo 113-0033 (Japan)

    2013-01-15

    Numerous large and small shell middens have been reported throughout the world. An interesting question is when the huge and thick shell middens were formed, and how many years were required to build up the whole midden. Shell middens contain not only shell fragments but also organic substances such as bones, nuts, acorn, and plant residues, which are suitable substances with which to establish {sup 14}C chronology of the middens. We have conducted {sup 14}C dating on terrestrial and marine materials collected from two lowland shell middens, the Higashimyo site in Japan (the Earliest Jomon period) and the Kimhae site in Korea (the Proto-Three Kingdom period), to establish high precision {sup 14}C chronologies and determine the time required for shell accumulation. According to Bayesian analysis of {sup 14}C ages from terrestrial samples, accumulation of Midden No. 1 at Higashimyo (altitude from -1.1 to -2.3 m a.s.l., {Delta}d = 1.2 m) started at around 8050-7950 cal BP and ended at 7950-7750 cal BP, lasting for ca. 100 cal yr, while accumulation of Midden No. 2 (altitude from -0.5 to -2.0 m a.s.l., {Delta}d = 1.5 m) started at around 8050-7800 cal BP and ended at 7800-7650 cal BP, lasting for ca. 200 cal yr. Thus the Midden No. 1 was abandoned a bit earlier than Midden No. 2, but the time range for sediment accumulation overlaps each other. Accumulation at the Kimhae shell midden (altitude from 5 to 14 m a.s.l., {Delta}d = 9 m) started at around the middle of the 1st C cal BC and ended at around the middle of the 3rd C cal AD, lasting for ca. 250 to 300 cal yr.

  12. Radiocarbon dates to access the origin of the ice man

    Energy Technology Data Exchange (ETDEWEB)

    Niklaus, R. [Institute of Particle Physics, ETH Zurich, Hongerberg (Switzerland)]|[Commonwealth Scientific and Industrial Research Organisation (CSIRO), North Ryde, NSW (Australia). Div. of Exploration Geoscience; Bonani, G. [Institute of Particle Physics, ETH Zurich, Hongerberg (Switzerland); Prinoth-Fornwagner, R. [Innsbruck Univ. (Austria)

    1996-12-31

    Different samples from the Late and Final Neolithic in Northern Italy were radiocarbon dated at the AMS Facility in Zurich, Switzerland in order to determine the origin of the Ice Man from the Hauslabjoch. The cultural classification was obtained on the basis of topological studies of the cooper axe and of the flint dagger as well as studies of artefact materials (the flint or the wood of a composite arrow), while the chronological classification of the Ice Man was obtained with the help of new and old radiocarbon dates. 9 refs., 1 tab., 2 figs.

  13. ‘Wiggle Matching’ Radiocarbon Dates

    NARCIS (Netherlands)

    Bronk Ramsey, C.; Plicht, J. van der; Weninger, B.; Boaretto, E.; Carmi, I.

    2001-01-01

    This paper covers three different methods of matching radiocarbon dates to the ‘wiggles’ of the calibration curve in those situations where the age difference between the 14C dates is known. These methods are most often applied to tree-ring sequences. The simplest approach is to use a classical Chi-

  14. The freshwater reservoir effect in radiocarbon dating

    DEFF Research Database (Denmark)

    Philippsen, Bente

    The freshwater reservoir effect can result in too high radiocarbon ages of samples from lakes and rivers, including the bones of people whose subsistence was based on freshwater fish, and pottery in which fish was cooked. In my talk, I will explain the causes and consequences of this effect. Two...... case studies will show the degree of variability of the freshwater reservoir effect over short and long timescales. Radiocarbon dating of recent water samples, aquatic plants and animals, shows that age differences of up to 2000 years can occur within one river. In the Limfjord, freshwater influence...... caused reservoir ages to vary between 250 and 700 years during the period 5400 BC - AD 700. Finally, I will discuss the implications of the freshwater reservoir effect for radiocarbon dating of Mesolithic pottery from inland sites of the Ertebølle culture in Northern Germany....

  15. Radiocarbon dating prehistoric pottery from Northern Europe

    DEFF Research Database (Denmark)

    Philippsen, Bente; Craig, Oliver; Heron, Carl;

    2012-01-01

    , such as when aquatic products have been prepared in the pottery. Soot can derive from old wood that was used for the hearth fire, or from (potentially aquatic) food that boiled over. Plant remains may have been present in the clay for a long time before manufacture of the pottery. Post......Direct dating of the pottery is an important goal in archaeological research and many attempts have been made using radiocarbon. One important goal has been to date the earliest pottery in a region to assess the origin and dispersal of ceramic technology. Also with the increasing application...... of organic residue analysis to study pottery use, it has become important to combine residue data with direct dates on the artefact being investigated. In this study we have radiocarbon dated different organic materials associated with archaeological potsherds from three Ertebølle sites in Northern Germany...

  16. Radiocarbon Dates from a Tomb in Mexico.

    Science.gov (United States)

    Furst, P T

    1965-02-01

    The first series of radiocarbon dates to be obtained from a deep shaft-and-chamber tomb of the type restricted in Mesoamerica to parts of Nayarit, Jalisco, and Colima in western Mexico ranges from 2230 +/- 100 years to 1710 +/- 80 years. Examination of the evidence indicates that for the present a date equivalent to A.D. 250 should be accepted for at least one phase, possibly a late phase, of the shaft tomb culture and for the hollow, polychrome figurines associated with the tombs.

  17. The freshwater reservoir effect in radiocarbon dating

    DEFF Research Database (Denmark)

    Philippsen, Bente

    2013-01-01

    The freshwater reservoir effect can result in anomalously old radiocarbon ages of samples from lakes and rivers. This includes the bones of people whose subsistence was based on freshwater fish, and pottery in which fish was cooked. Water rich in dissolved ancient calcium carbonates, commonly known...... as hard water, is the most common reason for the freshwater reservoir effect. It is therefore also called hardwater effect. Although it has been known for more than 60 years, it is still less well-recognized by archaeologists than the marine reservoir effect. The aim of this study is to examine the order...... of magnitude and degree of variability of the freshwater reservoir effect over short and long timescales. Radiocarbon dating of recent water samples, aquatic plants, and animals, shows that age differences of up to 2000 14C years can occur within one river. The freshwater reservoir effect has also implications...

  18. A combined PIXE-PIGE approach for the assessment of the diagenetic state of cremated bones submitted to AMS radiocarbon dating

    Science.gov (United States)

    Quarta, Gianluca; Calcagnile, Lucio; D'Elia, Marisa; Maruccio, Lucio; Gaballo, Valentina; Caramia, Annalisa

    2013-01-01

    Bone samples from a Bronze age necropolis in Northern Italy, exposed to different combustion temperatures, were submitted to XRD (X-ray Diffraction), PIXE (Particle Induced X-ray Emission) and PIGE (Particle Induced Gamma Ray Emission) analyses in order to obtain information about their diagenetic state. Structural carbonate was then extracted by acid hydrolysis and used for 14C-AMS (Accelerator Mass Spectrometry) dating. These analytical techniques permitted the study of the effects of the combustion temperature on the crystallinity of the bone apatite and on its elemental chemical composition in terms of major, minor and trace elements. The results indicate that combustion at temperatures above ∼700 °C induces changes in the bone crystalline structure, reducing the diagenetic uptake of elements from the burial environment.

  19. A combined PIXE-PIGE approach for the assessment of the diagenetic state of cremated bones submitted to AMS radiocarbon dating

    Energy Technology Data Exchange (ETDEWEB)

    Quarta, Gianluca, E-mail: gianluca.quarta@unisalento.it [CEDAD-Department of Engineering for Innovation, University of Salento, via per Monteroni, 73100 Lecce (Italy); Calcagnile, Lucio; D' Elia, Marisa; Maruccio, Lucio; Gaballo, Valentina; Caramia, Annalisa [CEDAD-Department of Engineering for Innovation, University of Salento, via per Monteroni, 73100 Lecce (Italy)

    2013-01-15

    Bone samples from a Bronze age necropolis in Northern Italy, exposed to different combustion temperatures, were submitted to XRD (X-ray Diffraction), PIXE (Particle Induced X-ray Emission) and PIGE (Particle Induced Gamma Ray Emission) analyses in order to obtain information about their diagenetic state. Structural carbonate was then extracted by acid hydrolysis and used for {sup 14}C-AMS (Accelerator Mass Spectrometry) dating. These analytical techniques permitted the study of the effects of the combustion temperature on the crystallinity of the bone apatite and on its elemental chemical composition in terms of major, minor and trace elements. The results indicate that combustion at temperatures above {approx}700 Degree-Sign C induces changes in the bone crystalline structure, reducing the diagenetic uptake of elements from the burial environment.

  20. Precision and reproducibility in AMS radiocarbon measurements.

    Energy Technology Data Exchange (ETDEWEB)

    Hotchkis, M.A.; Fink, D.; Hua, Q.; Jacobsen, G.E.; Lawson, E. M.; Smith, A.M.; Tuniz, C. [Australian Nuclear Science and Technology Organisation, Lucas Heights, NSW (Australia)

    1996-12-31

    Accelerator Mass Spectrometry (AMS) is a technique by which rare radioisotopes such as {sup 14}C can be measured at environmental levels with high efficiency. Instead of detecting radioactivity, which is very weak for long-lived environmental radioisotopes, atoms are counted directly. The sample is placed in an ion source, from which a negative ion beam of the atoms of interest is extracted, mass analysed, and injected into a tandem accelerator. After stripping to positive charge states in the accelerator HV terminal, the ions are further accelerated, analysed with magnetic and electrostatic devices and counted in a detector. An isotopic ratio is derived from the number of radioisotope atoms counted in a given time and the beam current of a stable isotope of the same element, measured after the accelerator. For radiocarbon, {sup 14}C/{sup 13}C ratios are usually measured, and the ratio of an unknown sample is compared to that of a standard. The achievable precision for such ratio measurements is limited primarily by {sup 14}C counting statistics and also by a variety of factors related to accelerator and ion source stability. At the ANTARES AMS facility at Lucas Heights Research Laboratories we are currently able to measure {sup 14}C with 0.5% precision. In the two years since becoming operational, more than 1000 {sup 14}C samples have been measured. Recent improvements in precision for {sup 14}C have been achieved with the commissioning of a 59 sample ion source. The measurement system, from sample changing to data acquisition, is under common computer control. These developments have allowed a new regime of automated multi-sample processing which has impacted both on the system throughput and the measurement precision. We have developed data evaluation methods at ANTARES which cross-check the self-consistency of the statistical analysis of our data. Rigorous data evaluation is invaluable in assessing the true reproducibility of the measurement system and aids in

  1. Smart AMS : Optimizing the measurement procedure for small radiocarbon samples

    NARCIS (Netherlands)

    Vries de, Hendrik

    2010-01-01

    Abstract In order to improve the measurement efficiency of radiocarbon samples, particularly small samples (< 300 µg C), the measurement procedure was optimized using Smart AMS, which is the name of the new control system of the AMS. The system gives the

  2. Radiocarbon dating of late pleistocene marine shells from the southern north sea

    NARCIS (Netherlands)

    Busschers, F.S.; Wesselingh, F.P.; Kars, R.H.; Versluijs-Helder, M.; Wallinga, J.; Bosch, J.H.A.; Timmner, J.; Nierop, K.G.J.; Meijer, T.; Bunnik, F.P.M.; Wolf, De H.

    2014-01-01

    This article presents a set of Late Pleistocene marine mollusk radiocarbon (AMS) age estimates of 30-50 C-14 kyr BP, whereas a MIS5 age (>75 ka) is indicated by quartz and feldspar OSL dating, biostratigraphy, U-Th dating, and age-depth relationships with sea level. These results indicate that th

  3. Constructing deposition chronologies for peat deposits using radiocarbon dating

    Directory of Open Access Journals (Sweden)

    N. Piotrowska

    2011-06-01

    Full Text Available Radiocarbon dating is one of the main methods used to establish peat chronologies. This article reviews the basis of the method and its application to dating of peat deposits. Important steps in the radiocarbon dating procedure are described, including selection and extraction of material (and fractions for dating, chemical and physical preparation of media suitable for measurements, measurements of 14C activity or concentration, calculations, calibration of results and age-depth modelling.

  4. Assessing screening criteria for the radiocarbon dating of bone mineral

    Energy Technology Data Exchange (ETDEWEB)

    Fernandes, Ricardo, E-mail: ldv1452@gmail.com [Leibniz Labor for Isotopic and Radiometric Dating, Max-Eyth-Str. 11-13, 24118 Kiel (Germany); Graduate School Human Development in Landscapes, Christian Albrecht University, Kiel (Germany); Huels, Matthias [Leibniz Labor for Isotopic and Radiometric Dating, Max-Eyth-Str. 11-13, 24118 Kiel (Germany); Nadeau, Marie-Josee; Grootes, Pieter M. [Leibniz Labor for Isotopic and Radiometric Dating, Max-Eyth-Str. 11-13, 24118 Kiel (Germany); Graduate School Human Development in Landscapes, Christian Albrecht University, Kiel (Germany); Garbe-Schoenberg, C.-Dieter [Institute of Geosciences, Marine Climate Research and ICPMS Lab, Kiel University, Ludewig-Meyn-Str. 10, D-24118 Kiel (Germany); Graduate School Human Development in Landscapes, Christian Albrecht University, Kiel (Germany); Hollund, Hege I. [Institute for Geo- and Bioarchaeology, The VU University, De Boelelaan 1085, 1081 HV Amsterdam (Netherlands); Lotnyk, Andriy [Faculty of Engineering, Institute for Material Science, Synthesis and Real Structure, Kiel University, Kaiserstr. 2, D-24143 Kiel (Germany); Leibniz Institute of Surface Modification (IOM), Permoserstr. 15, D-04318 Leipzig (Germany); Kienle, Lorenz [Faculty of Engineering, Institute for Material Science, Synthesis and Real Structure, Kiel University, Kaiserstr. 2, D-24143 Kiel (Germany); Graduate School Human Development in Landscapes, Christian Albrecht University, Kiel (Germany)

    2013-01-15

    Radiocarbon dating of bone mineral (carbonate in the apatite lattice) has been the target of sporadic research for the last 40 years. Results obtained by different decontamination protocols have, however, failed to provide a consistent agreement with reference ages. In particular, quality criteria to assess bone mineral radiocarbon dating reliability are still lacking. Systematic research was undertaken to identify optimal preservation criteria for bone mineral in archeological bones. Six human long bones, originating from a single site, were radiocarbon-dated both for collagen and apatite, with the level of agreement between the dates providing an indication of exogenous carbon contamination. Several techniques (Histology, FTIR, TEM, LA-ICP-MS) were employed to determine the preservation status of each sample. Research results highlight the importance of a micro-scale approach in establishing bone preservation, in particular the use of trace element concentration profiles demonstrated its potential use as a viable sample selection criterion for bone carbonate radiocarbon dating.

  5. Radiocarbon dating of a very large African baobab.

    Science.gov (United States)

    Patrut, Adrian; von Reden, Karl F; Lowy, Daniel A; Alberts, Andries H; Pohlman, John W; Wittmann, Rudolf; Gerlach, Dana; Xu, Li; Mitchell, Clark S

    2007-11-01

    In late 2004, Grootboom, probably the largest known African baobab (Adansonia digitata L.), collapsed unexpectedly in northeastern Namibia. Ten wood samples collected from different areas of the trunk were processed and investigated by accelerator mass spectrometry radiocarbon dating. The radiocarbon dates of three samples were greater than 1000 years BP (radiocarbon years before present, i.e., before AD 1950). The corresponding calibrated calendar age of the oldest sample was 1275 +/- 50 years, making Grootboom the oldest known angiosperm tree with reliable dating results. Variations in radiocarbon dates among the wood samples indicated that, morphologically, Grootboom was a quintuple tree, whereas genetically, it was a single individual. Ages of extreme lateral samples revealed that, over the past 500-600 years, Grootbooom had almost ceased growing, providing information about climate changes in central southern Africa. The sudden demise of Grootboom coincided with the spread of the poorly studied baobab disease, which has become epidemic in Namibia.

  6. Radiocarbon dating of twentieth century works of art

    Science.gov (United States)

    Petrucci, F.; Caforio, L.; Fedi, M.; Mandò, P. A.; Peccenini, E.; Pellicori, V.; Rylands, P.; Schwartzbaum, P.; Taccetti, F.

    2016-11-01

    The atmospheric tests of nuclear weapons caused a sudden increase in the radiocarbon concentration in the atmosphere from 1955, reaching its maximum value in 1963-1965. Once the nuclear tests in the atmosphere were halted, the 14C concentration started to decrease. This behavior of the radiocarbon concentration is called the "Bomb Peak", and it has successfully been used as a tool for high-precision radiocarbon measurements, in forensic sciences and biology. In the art field, the possibility of dating canvas, wood and paper, widely used as supports for paintings, may be an invaluable tool in modern art studies.

  7. Radiocarbon dating of ancient bronze statues: Preliminary results from the Riace statues

    Energy Technology Data Exchange (ETDEWEB)

    Calcagnile, L., E-mail: lucio.calcagnile@unile.i [CEDAD, Department of Innovation Engineering, University of Salento, Via per Monteroni, 73100 Lecce (Italy); D' Elia, M.; Quarta, G. [CEDAD, Department of Innovation Engineering, University of Salento, Via per Monteroni, 73100 Lecce (Italy); Vidale, M. [Istituto Centrale per il Restauro, Piazza San Francesco di Paola, 9, 00184 Rome (Italy)

    2010-04-15

    The low amount of material needed for the measurements makes AMS radiocarbon a technique suitable for the dating of ancient bronze artefacts through the analysis of the organic residues contained into the casting cores. We present the results of the AMS radiocarbon dating analyses carried out on the organic remains extracted from the casting cores of the Riace bronzes, among the most famous and well preserved sculptures of the Greek-Classical period. Although different dating hypotheses have been suggested on the base of stylistic considerations, no conclusive answers are, so far, available. The sample selection and preparation protocols of the different kind of organic materials (charred wood, vegetal remains and animal hairs) are described as well as the interpretation of the results in the frame of the current dating hypotheses and available analytical information about the casting technology.

  8. Radiocarbon dating of Mesolithic pottery from Northern Germany

    DEFF Research Database (Denmark)

    Philippsen, Bente

    2013-01-01

    The earliest pottery in Schleswig-Holstein, Northern Germany, was produced by the Final Mesolithic Ertebølle culture. Radiocarbon dating of food crusts on Ertebølle pottery indicated that ceramics from inland sites were substantially older than those from the coast. Therefore, a freshwater...... of magnitude and the degree of variability of the freshwater reservoir effect in Schleswig-Holstein. Experiments with copies of Ertebølle vessels yielded reference material for radiocarbon dating and stable isotope analysis. Food crusts, terrestrial samples and fishbones from two Ertebølle inland sites were...... analysed as well. It could be shown that the inland pottery most probably has the same age as the coastal pottery. Furthermore, I will present some methodological considerations about pottery dating and a pilot study where food crusts as well as total lipid extracts were dated....

  9. Radiocarbon dating of ancient rock paintings

    Energy Technology Data Exchange (ETDEWEB)

    Ilger, W.A.; Hyman, M.; Rowe, M.W. [Texas A and M Univ., College Station, TX (United States). Dept. of Chemistry; Southon, J. [Lawrence Livermore National Lab., CA (United States)

    1995-06-20

    This report presents progress made on a technique for {sup 14}C dating pictographs. A low-temperature oxygen plasma is used coupled with high-vacuum technologies to selectively remove C-containing material in the paints without contamination from inorganic carbon from rock substrates or accretions.

  10. Radiocarbon accelerator mass spectrometry (AMS) sample preparation laboratory in Brazil

    Energy Technology Data Exchange (ETDEWEB)

    Macario, Kita D.; Gomes, Paulo R. S.; Anjos, Roberto M. dos; Linares, Roberto; Queiroz, Eduardo; Oliveira, Fabiana M. de; Cardozo, Laio [Universidade Federal Fluminense (UFF), Niteroi, RJ (Brazil); Carvalho, Carla R.A. [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil)

    2011-07-01

    Full text: For decades Accelerator Mass Spectrometry has been widely used for radiocarbon measurements all over the world with application in several fields of science from archaeology to geosciences. This technique provides ultrasensitive analysis of reduced size samples or even specific compounds since sample atoms are accelerated to high energies and measured using nuclear particle detectors. Sample preparation is extremely important for accurate radiocarbon measurement and includes chemical pre-treatment to remove all possible contaminants. For beam extraction in the accelerator ion source, samples are usually converted to graphite. In this work we report a new radiocarbon sample preparation facility installed at the Physics Institute of Universidade Federal Fluminense (UFF), in Brazil. At the Nuclear Chronology Laboratory (LACRON) samples are chemically treated and converted to carbon dioxide by hydrolysis or combustion. A stainless steel based vacuum line was constructed for carbon dioxide separation and graphitization is performed in sealed quartz tubes in a muffle oven. Successful graphite production is important to provide stable beam currents and to minimize isotopic fractionation. Performance tests for graphite production are currently under way and isotopic analysis will soon be possible with the acquisition of a Single Stage AMS System by our group. The Single Stage Accelerator produced by National Electrostatic Corporation is a 250 kV air insulated accelerator especially constructed to measure the amount of {sup 14}C in small modern graphite samples to a precision of 0.3 % or better. With the installation of such equipment in the first half of 2012, UFF will be ready to perform the 14C -AMS technique. (author)

  11. Radiocarbon dating of a pine tree (Pinus densiflora) from Yeongwol, Korea

    Energy Technology Data Exchange (ETDEWEB)

    Kim, C.H.; Lee, J.H.; Kang, J.; Song, S.; Yun, M.H. [AMS Lab., NCIRF, Seoul National University, Seoul 151-742 (Korea, Republic of); Kim, J.C. [Dept. of Physics and Astronomy, Seoul National University, Seoul 151-742 (Korea, Republic of)

    2015-10-15

    We report the results of the dating of a pine tree (Pinus densiflora) from Yeongwol, Korea. The age of the tree was estimated to be in the range of hundreds of years, however, the tree had been broken by a strong wind in March 2010 and now only the stump of the tree is left. At the time of sampling in 2014, there were several decayed parts in the stump, so using the usual dendrochronological method (i.e. ring counting) for dating was difficult. However, we found a small wood sample with tree rings near the center of the stump that could be used for radiocarbon wiggle-match dating. Radiocarbon dates were determined using Accelerator mass spectrometry (AMS). The IntCal13 curve was used to calibrate the radiocarbon dates, and the wiggle matching technique was used to reduce the error of the calibrated ages. Based on the dating results, we suggest that the pine tree is approximately 300 years or older.

  12. Radiocarbon dating of a pine tree (Pinus densiflora) from Yeongwol, Korea

    Science.gov (United States)

    Kim, C. H.; Lee, J. H.; Kang, J.; Song, S.; Yun, M. H.; Kim, J. C.

    2015-10-01

    We report the results of the dating of a pine tree (Pinus densiflora) from Yeongwol, Korea. The age of the tree was estimated to be in the range of hundreds of years, however, the tree had been broken by a strong wind in March 2010 and now only the stump of the tree is left. At the time of sampling in 2014, there were several decayed parts in the stump, so using the usual dendrochronological method (i.e. ring counting) for dating was difficult. However, we found a small wood sample with tree rings near the center of the stump that could be used for radiocarbon wiggle-match dating. Radiocarbon dates were determined using Accelerator mass spectrometry (AMS). The IntCal13 curve was used to calibrate the radiocarbon dates, and the wiggle matching technique was used to reduce the error of the calibrated ages. Based on the dating results, we suggest that the pine tree is approximately 300 years or older.

  13. Radiocarbon dating of small terrestrial gastropod shells in North America

    Science.gov (United States)

    Pigati, J.S.; Rech, J.A.; Nekola, J.C.

    2010-01-01

    Fossil shells of small terrestrial gastropods are commonly preserved in wetland, alluvial, loess, and glacial deposits, as well as in sediments at many archeological sites. These shells are composed largely of aragonite (CaCO3) and potentially could be used for radiocarbon dating, but they must meet two criteria before their 14C ages can be considered to be reliable: (1) when gastropods are alive, the 14C activity of their shells must be in equilibrium with the 14C activity of the atmosphere, and (2) after burial, their shells must behave as closed systems with respect to carbon. To evaluate the first criterion, we conducted a comprehensive examination of the 14C content of the most common small terrestrial gastropods in North America, including 247 AMS measurements of modern shell material (3749 individual shells) from 46 different species. The modern gastropods that we analyzed were all collected from habitats on carbonate terrain and, therefore, the data presented here represent worst-case scenarios. In sum, ~78% of the shell aliquots that we analyzed did not contain dead carbon from limestone or other carbonate rocks even though it was readily available at all sites, 12% of the aliquots contained between 5 and 10% dead carbon, and a few (3% of the total) contained more than 10%. These results are significantly lower than the 20-30% dead carbon that has been reported previously for larger taxa living in carbonate terrain. For the second criterion, we report a case study from the American Midwest in which we analyzed fossil shells of small terrestrial gastropods (7 taxa; 18 AMS measurements; 173 individual shells) recovered from late-Pleistocene sediments. The fossil shells yielded 14C ages that were statistically indistinguishable from 14C ages of well-preserved plant macrofossils from the same stratum. Although just one site, these results suggest that small terrestrial gastropod shells may behave as closed systems with respect to carbon over geologic

  14. Radiocarbon dating of diatom-bound organic compounds

    Science.gov (United States)

    Hatte, C.; Hodgins, G.; Jull, T.; Cruz, R.; Lange, T.; Biddulph, D.

    2006-12-01

    We present a new method for obtaining radiocarbon dates for the proteins intrinsic to diatom frustules (sillafin). By asserting age models for sediment cores that lack calcium carbonate, this method will improve interpretations of diatom-based paleoproxies either marine or lacustrine. In preparation for radiocarbon dating by Accelerator Mass Spectrometry, diatoms were first concentrated out of the sediment. Through chemical and physical treatments that will be discussed and compared here, diatoms frustules are then freed of any surface-bound organic matter. Compounds intrinsic to diatoms frustules are then released from their opal matrix by HF dissolution. Since we have eliminated any of potentially contaminating organic matter, this method differs from approaches based on specific compounds extraction from a complex organic mixture by preparative chromatography such as proposed by Ingalls et al. (2004, Mar. Chem). The advantage of our method is that it does not require heavy cost investment. The method was applied to samples from a marine core collected in the Southern Ocean, that spans the last climatic cycle. Diatoms rich sediments from a Holocene lacustrine/palustrine record from Texas were also investigated. We report on the radiocarbon dating results obtained on organic matter at each step of the chemical treatment, from bulk to sillafin and their interpretation.

  15. Reevaluation of dating results for some {sup 14}C - AMS applications on the basis of the new calibration curves available

    Energy Technology Data Exchange (ETDEWEB)

    Macario, K.D.; Gomes, P.R.S.; Anjos, R.M. [Universidade Federal Fluminense (UFF), Niteroi, RJ (Brazil). Inst. de Fisica

    2007-03-15

    In this paper we describe briefly some characteristics of the Accelerator Mass Spectrometry (AMS) technique and the need of corrections in the radiocarbon ages by specific calibration curves. Then we discuss previous results of some Brazilian projects where radiocarbon AMS had been applied in order to reevaluate the dates obtained on the basis of the new calibration curves available. (author)

  16. Radiocarbon dates from Wairau Bar and their implications for the prehistoric colonisation of New Zealand

    Energy Technology Data Exchange (ETDEWEB)

    Higham, T.F.G. [Waikato Univ., Hamilton (New Zealand); Anderson, A.J. [Australian National Univ., Canberra, ACT (Australia)

    1997-12-31

    A set of thirteen moa eggshell samples from burial features at the Wairau Bar site were used for dating. The samples were obtained from the Canterbury Museum in Christchurch where they have been displayed as part of a permanent exhibition.Three marine shell samples were also analysed. Radiocarbon dating of the samples was carried out using conventional and AMS techniques. The results will be presented and the archaeological implications for the prehistoric colonization of New Zealand will be discussed. Paper no. 39; Extended abstract. 7 refs.

  17. Biofuel proportions in fuels by AMS radiocarbon method

    Energy Technology Data Exchange (ETDEWEB)

    Oinonen, M., E-mail: markku.j.oinonen@helsinki.f [Dating Laboratory, Finnish Museum of Natural History, University of Helsinki, P.O. Box 64, FIN-00014 (Finland); Hakanpaeae-Laitinen, H. [Neste Oil Oyj, Research and Technology, Porvoo (Finland); Haemaelaeinen, K.; Kaskela, A.; Jungner, H. [Dating Laboratory, Finnish Museum of Natural History, University of Helsinki, P.O. Box 64, FIN-00014 (Finland)

    2010-04-15

    Within the context of expanding use of biofuels in transport worldwide, a need has emerged to accurately determine biofuel proportions of fuels. In this study, the radiocarbon method by AMS has been used to study the fuel mixtures containing 2%, 5% and 30% of the NExBTL renewable diesel, particularly. Special effort has been put to develop reproducible pretreatment and combustion methods and to verify the reliable determination of the low biofuel proportions - corresponding to the present status of the European-wide biofuel usage. The developed procedures are ready to meet the requirements set in the ASTM D 6866-06a standard and demonstrate our ability to perform reliable measurements on biofuel proportions in fuels.

  18. Year of Birth Determination Using Radiocarbon Dating of Dental Enamel

    Energy Technology Data Exchange (ETDEWEB)

    Buchholz, B A; Spalding, K L

    2009-03-10

    Radiocarbon dating is typically an archaeological tool rather than a forensic one. Recently however, we have shown that the amount of radiocarbon present in tooth enamel, as a result of nuclear bomb testing during the cold war, is a remarkably accurate indicator of when a person is born. Enamel isolated from human teeth is processed to form graphite and carbon-14 ({sup 14}C) levels are measured using accelerator mass spectrometry. Since there is no turnover of enamel after it is formed, {sup 14}C levels in the enamel represent {sup 14}C levels in the atmosphere at the time of its formation. In this paper we describe the strategy used to determine the date of birth of an individual based on radiocarbon levels in tooth enamel, focusing on the methodology of this strategy. Year of birth information can significantly assist police investigators when the identity of a deceased individual is unknown. In such cases police will try to match particulars of the unidentified individual (which is often only gender and/or an estimate of age), with particulars from missing persons lists.

  19. Accelerator radiocarbon dating of evidence for prehistoric horticulture in Illinois

    Science.gov (United States)

    Conard, N.; Asch, D.L.; Asch, N.B.; Elmore, D.; Gove, H.; Rubin, M.; Brown, J.A.; Wiant, M.D.; Farnsworth, K.B.; Cook, T.G.

    1984-01-01

    With the development of direct detection radiocarbon dating, which uses an accelerator as part of a highly selective mass spectrometer, it is now possible to determine the age of milligram samples of organic materials1-5. One application of accelerator dating is in evaluating scanty, sometimes controversial evidence for early horticulture throughout the world. We have now used the technique to date small samples of carbonized, cultivated plant remains from archaeological sites in Illinois. The results, reported here, establish (1) that squash was introduced by 7,000 yr ago, 2,500 yr before eastern North American records previously reported; (2) that horticulture involving indigenous plants had begun by 4,000 BP in eastern North America with domestication of Iva annua, a small-seeded annual; (3) that anomalous discoveries of Archaic period maize represent contaminants; and (4) that introduction of maize by initial Middle Woodland times (~2,000 BP) is questionable.

  20. Brief communication: preliminary radiocarbon dates from Florida crania in Hrdlička's gulf states catalog.

    Science.gov (United States)

    Stojanowski, Christopher M; Johnson, Kent M

    2011-05-01

    Aleš Hrdlička produced a tremendous amount of data in his career, much of which was published in a series of catalogs by the US National Museum. The Gulf States catalog, for example, contains raw craniometric data for over 700 individuals from the state of Florida alone. However, many of these skeletons are poorly sourced by Hrdlička, thus limiting their utility in modern bioarchaeological analyses where context is critical. In particular, the age of the skeletal material is often based solely on associated material culture and information on the sites themselves is not presented by Hrdlička. To address this impasse we attempted radiocarbon dates for 10 of the largest Florida sites published in the Gulf States catalog. In addition, archival data in the form of unpublished field notes and personal correspondence were accessed to better contextualize the radiocarbon dates and to provide some guidance on the degree of temporal variability at the sites. Eight AMS radiocarbon dates were successful. Archival data was of variable quality per site. In some cases very little is known about the provenience of the specimens. In other cases, however, individual burials could be allocated to specific strata within specific mounds. The relevance of using published raw data is discussed with respect to the Howells and Boas Immigrant datasets and the impact the dissemination of these resources has had on the discipline.

  1. New radiocarbon dates for Milu (Elaphurus davidianus) sub-fossils from southeast China

    Energy Technology Data Exchange (ETDEWEB)

    Ding, X.F. [State Key Laboratory of Nuclear Physics and Technology and Institute of Heavy Ion Physics, School of Physics, Peking University, Beijing 100871 (China); Shen, C.D., E-mail: cdshen@gig.ac.cn [State Key Laboratory of Isotope Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, 510640 Guangzhou (China); Ding, P.; Yi, W.X. [State Key Laboratory of Isotope Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, 510640 Guangzhou (China); Fu, D.P.; Liu, K.X. [State Key Laboratory of Nuclear Physics and Technology and Institute of Heavy Ion Physics, School of Physics, Peking University, Beijing 100871 (China)

    2013-01-15

    Milu (Elaphurus davidianus, Pere David's deer) is one of the few species of large mammals that became extinct in the wild, but survived domestically. A good understanding of expansion and habitat is required if the reintroduction of Milu into the wild is to be implemented. Among the widely reported findings of Milu sub-fossils, only a small fraction have been dated. Here we report new AMS radiocarbon dates on Milu sub-fossil samples unearthed from two sites at Qingdun, Jiangsu and Fujiashan, Zhejiang in southeast China. These AMS {sup 14}C ages of Milu sub-fossils provide new evidence for the presence of Milu expansion in the lower reaches of the Yangtze River during the Holocene Optimum interval from 5000 yr BC to 3000 yr BC. These new ages also have important implications for the reconstruction of the paleoclimate and paleogeography during the Neolithic Period in southeast China.

  2. Radiocarbon dating of VIRI bone samples using ultrafiltration

    Energy Technology Data Exchange (ETDEWEB)

    Minami, Masayo, E-mail: minami@nendai.nagoya-u.ac.jp [Center for Chronological Research, Nagoya University, Nagoya 464-8602 (Japan); Yamazaki, Kana [Faculty of Science, Nagoya University, Nagoya 464-8602 (Japan); Omori, Takayuki [University Museum, University of Tokyo, Tokyo 113-0033 (Japan); Nakamura, Toshio [Center for Chronological Research, Nagoya University, Nagoya 464-8602 (Japan)

    2013-01-15

    Ultrafiltration can effectively remove low-molecular-weight (LMW) contaminants from bone gelatin to extract high-molecular-weight (HMW) proteins that are derived from original bone collagen, though it cannot remove HMW collagen crosslinked with humic acids. Therefore, ultrafiltration is often used to obtain more accurate {sup 14}C dates of bones. However, ultrafiltration may introduce new contaminants to bone gelatins, mainly from ultrafilters used. To study the effects of ultrafiltration on {sup 14}C age, we analyzed the C/N ratio, {delta}{sup 13}C{sub PDB} and {delta}{sup 15}N{sub AIR} values, and {sup 14}C ages of acid-soluble bone collagen obtained by decalcification, gelatin extracted from acid-insoluble bone collagen, and the HMW gelatin and LMW fractions produced during ultrafiltration of the extracted gelatin. Bone samples from the Fifth International Radiocarbon Intercomparison (VIRI) were used: VIRI-E (mammoth), -F (horse), -G (human), and -I (whale). In this study, carbon and nitrogen content and gelatin yields were used to evaluate collagen preservation in the VIRI bone samples. Radiocarbon ages, {delta}{sup 13}C{sub PDB} and {delta}{sup 15}N{sub AIR} values of unfiltered and HMW gelatins were obtained and compared with the published consensus values. The LMW fraction was found to exhibit different values from those of the other fractions, indicating the possible presence of extraneous contamination. The Vivaspin Trade-Mark-Sign 6 ultrafilters used in this study were analyzed and radiocarbon dated both before and after cleaning. We present evidence to suggest that LMW fraction contaminants could be derived from the ultrafilters rather than humic substances. Excessively long ultrafiltration time was suspected to have contaminated the bone samples with material from the ultrafilter, because those samples exhibited older {sup 14}C ages than did those filtered for shorter durations. The results in this study indicate that {sup 14}C ages of unfiltered

  3. Radiocarbon dating and compositional analysis of pre-Columbian human bones

    Science.gov (United States)

    Andrade, E.; Solís, C.; Canto, C. E.; de Lucio, O. G.; Chavez, E.; Rocha, M. F.; Villanueva, O.; Torreblanca, C. A.

    2014-08-01

    Analysis of ancient human bones found in "El Cóporo", an archaeological site in Guanajuato, Mexico; were performed using a multi techniques scheme: 14C radiocarbon dating, IBA (Ion Beam Analysis), SEM-EDS (Scanning Electron Microscope Energy Dispersive X-ray Spectroscopy). We measured the elemental composition of the bones, especially some with a superficial black pigmentation. Soil samples collected from the burial place were also analyzed. The 14C dating was performed with a new High Voltage Europe 1 MV Tandentron Accelerator Mass Spectrometer (AMS) recently installed in the IFUNAM (Instituto de Física, Universidad Nacional Autónoma de México). The radiocarbon dating allowed us to determine the date of death of the individual in a period between the year 890 and 975 AD, which is consistent with the late period of the Cóporo civilization. The element sample analysis of bones with the surface black pigmentation show higher levels of Fe, Mn and Ba compared when bone's black surface was mechanically removed. These three elements were found in soil samples from the skeleton burial place. These results indicate more likely that the bone black coloration is due to a postmortem alteration occurring in the burial environment.

  4. Radiocarbon dating and compositional analysis of pre-Columbian human bones

    Energy Technology Data Exchange (ETDEWEB)

    Andrade, E., E-mail: andrade@fisica.unam.mx [Instituto de Física, Universidad Nacional Autónoma de México, Apartado Postal 20-364, 01000 México D.F. (Mexico); Solís, C.; Canto, C.E.; Lucio, O.G. de [Instituto de Física, Universidad Nacional Autónoma de México, Apartado Postal 20-364, 01000 México D.F. (Mexico); Chavez, E. [ESIME-Z, Instituto Politécnico Nacional, ALM Zacatenco, 07738 México D.F. (Mexico); Rocha, M.F.; Villanueva, O.; Torreblanca, C.A. [Centro INAH Zacatecas, Miguel Auza No. 205, Col. Centro, Zacatecas/Zacatecas CP 98000 (Mexico)

    2014-08-01

    Analysis of ancient human bones found in “El Cóporo”, an archaeological site in Guanajuato, Mexico; were performed using a multi techniques scheme: {sup 14}C radiocarbon dating, IBA (Ion Beam Analysis), SEM-EDS (Scanning Electron Microscope Energy Dispersive X-ray Spectroscopy). We measured the elemental composition of the bones, especially some with a superficial black pigmentation. Soil samples collected from the burial place were also analyzed. The {sup 14}C dating was performed with a new High Voltage Europe 1 MV Tandentron Accelerator Mass Spectrometer (AMS) recently installed in the IFUNAM (Instituto de Física, Universidad Nacional Autónoma de México). The radiocarbon dating allowed us to determine the date of death of the individual in a period between the year 890 and 975 AD, which is consistent with the late period of the Cóporo civilization. The element sample analysis of bones with the surface black pigmentation show higher levels of Fe, Mn and Ba compared when bone’s black surface was mechanically removed. These three elements were found in soil samples from the skeleton burial place. These results indicate more likely that the bone black coloration is due to a postmortem alteration occurring in the burial environment.

  5. Radiocarbon dating of glacier ice: overview, optimisation, validation and potential

    Science.gov (United States)

    Uglietti, Chiara; Zapf, Alexander; Jenk, Theo Manuel; Sigl, Michael; Szidat, Sönke; Salazar, Gary; Schwikowski, Margit

    2016-12-01

    High-altitude glaciers and ice caps from midlatitudes and tropical regions contain valuable signals of past climatic and environmental conditions as well as human activities, but for a meaningful interpretation this information needs to be placed in a precise chronological context. For dating the upper part of ice cores from such sites, several relatively precise methods exist, but they fail in the older and deeper parts, where plastic deformation of the ice results in strong annual layer thinning and a non-linear age-depth relationship. If sufficient organic matter such as plant, wood or insect fragments were found, radiocarbon (14C) analysis would have thus been the only option for a direct and absolute dating of deeper ice core sections. However such fragments are rarely found and, even then, they would not be very likely to occur at the desired depth and resolution. About 10 years ago, a new, complementary dating tool was therefore introduced by our group. It is based on extracting the µg-amounts of the water-insoluble organic carbon (WIOC) fraction of carbonaceous aerosols embedded in the ice matrix for subsequent 14C dating. Since then this new approach has been improved considerably by reducing the measurement time and improving the overall precision. Samples with ˜ 10 µg WIOC mass can now be dated with reasonable uncertainty of around 10-20 % (variable depending on sample age). This requires about 300 to 800 g of ice for WIOC concentrations typically found in midlatitude and low-latitude glacier ice. Dating polar ice with satisfactory age precision is still not possible since WIOC concentrations are around 1 order of magnitude lower. The accuracy of the WIOC 14C method was validated by applying it to independently dated ice. With this method, the deepest parts of the ice cores from Colle Gnifetti and the Mt Ortles glacier in the European Alps, Illimani glacier in the Bolivian Andes, Tsambagarav ice cap in the Mongolian Altai, and Belukha glacier in the

  6. Earliest Human Presence in North America Dated to the Last Glacial Maximum: New Radiocarbon Dates from Bluefish Caves, Canada

    Science.gov (United States)

    Bourgeon, Lauriane; Burke, Ariane; Higham, Thomas

    2017-01-01

    The timing of the first entry of humans into North America is still hotly debated within the scientific community. Excavations conducted at Bluefish Caves (Yukon Territory) from 1977 to 1987 yielded a series of radiocarbon dates that led archaeologists to propose that the initial dispersal of human groups into Eastern Beringia (Alaska and the Yukon Territory) occurred during the Last Glacial Maximum (LGM). This hypothesis proved highly controversial in the absence of other sites of similar age and concerns about the stratigraphy and anthropogenic signature of the bone assemblages that yielded the dates. The weight of the available archaeological evidence suggests that the first peopling of North America occurred ca. 14,000 cal BP (calibrated years Before Present), i.e., well after the LGM. Here, we report new AMS radiocarbon dates obtained on cut-marked bone samples identified during a comprehensive taphonomic analysis of the Bluefish Caves fauna. Our results demonstrate that humans occupied the site as early as 24,000 cal BP (19,650 ± 130 14C BP). In addition to proving that Bluefish Caves is the oldest known archaeological site in North America, the results offer archaeological support for the “Beringian standstill hypothesis”, which proposes that a genetically isolated human population persisted in Beringia during the LGM and dispersed from there to North and South America during the post-LGM period. PMID:28060931

  7. Mortar radiocarbon dating: preliminary accuracy evaluation of a novel methodology.

    Science.gov (United States)

    Marzaioli, Fabio; Lubritto, Carmine; Nonni, Sara; Passariello, Isabella; Capano, Manuela; Terrasi, Filippo

    2011-03-15

    Mortars represent a class of building and art materials that are widespread at archeological sites from the Neolithic period on. After about 50 years of experimentation, the possibility to evaluate their absolute chronology by means of radiocarbon ((14)C) remains still uncertain. With the use of a simplified mortar production process in the laboratory environment, this study shows the overall feasibility of a novel physical pretreatment for the isolation of the atmospheric (14)CO(2) (i.e., binder) signal absorbed by the mortars during their setting. This methodology is based on the assumption that an ultrasonic attack in liquid phase isolates a suspension of binder carbonates from bulk mortars. Isotopic ((13)C and (14)C), % C, X-ray diffractometry (XRD), and scanning electron microscopy (SEM) analyses were performed to characterize the proposed methodology. The applied protocol allows suppression of the fossil carbon (C) contamination originating from the incomplete burning of the limestone during the quick lime production, providing unbiased dating for "laboratory" mortars produced operating at historically adopted burning temperatures.

  8. Dating the time of birth: A radiocarbon calibration curve for human eye-lens crystallines

    DEFF Research Database (Denmark)

    Kjeldsen, Henrik; Heinemeier, Jan; Heegaard, Steffen;

    2010-01-01

    Radiocarbon bomb-pulse dating has been used to measure the formation age of human eye-lens crystallines. Lens crystallines are special proteins in the eye-lens that consist of virtually inert tissue. The experimental data show that the radiocarbon ages to a large extent reflect the time of birth...

  9. Molecular sieve sampling of CO{sub 2} from decomposition of soil organic matter for AMS radiocarbon measurements

    Energy Technology Data Exchange (ETDEWEB)

    Haemaelaeinen, K. [Dating Laboratory, Finnish Museum of Natural History, P.O. Box 64, University of Helsinki, FIN 00014 (Finland); Fritze, H. [Finnish Forest Research Institute (METLA), Vantaa (Finland); Jungner, H. [Dating Laboratory, Finnish Museum of Natural History, P.O. Box 64, University of Helsinki, FIN 00014 (Finland); Karhu, K. [Finnish Environment Institute (SYKE), Helsinki (Finland); Oinonen, M., E-mail: markku.j.oinonen@helsinki.f [Dating Laboratory, Finnish Museum of Natural History, P.O. Box 64, University of Helsinki, FIN 00014 (Finland); Sonninen, E. [Dating Laboratory, Finnish Museum of Natural History, P.O. Box 64, University of Helsinki, FIN 00014 (Finland); Spetz, P.; Tuomi, M.; Vanhala, P.; Liski, J. [Finnish Environment Institute (SYKE), Helsinki (Finland)

    2010-04-15

    A molecular sieve based procedure has been established for sampling CO{sub 2} of decomposing soil organic matter for AMS radiocarbon measurements. The sampling and desorption lines are capable to produce well measurable (>1 mg) AMS targets.

  10. ASSESSMENT OF INTERLABORATORY PRETREATMENT PROTOCOLS BY RADIOCARBON DATING AN ELK BONE FOUND BELOW LAACHER SEE TEPHRA AT MIESENHEIM IV (RHINELAND, GERMANY)

    NARCIS (Netherlands)

    Fiedel, Stuart J.; Southon, John R.; Taylor, R. E.; Kuzmin, Yaroslav V.; Street, Martin; Higham, Thomas F. G.; van der Plicht, Johannes; Nadeau, Marie-Josee; Nalawade-Chavan, Shweta; Hatté, C.; Jull, A.J.T.

    2013-01-01

    Four accelerator mass spectrometry (AMS) facilities undertook an interlaboratory exercise designed to examine the reliability and reproducibility of radiocarbon determinations on bone by dating a sample of elk (Alces alces) from Miesenheim IV. This specimen is derived from a secure geological contex

  11. VARIABILITY IN RADIOCARBON DATES IN MIDDLE PLENIGLACIAL WOOD FROM KURTAK (CENTRAL SIBERIA)

    NARCIS (Netherlands)

    Haesaerts, P.; Damblon, F.; Drozdov, N.; Checha, V.; van der Plicht, J.

    2014-01-01

    The chronology of long Upper Pleistocene loess sequences in Eurasia is based on combined pedostratigraphy and radiocarbon dating of high-quality charcoal. The accuracy of such a chronology depends on the reproducibility and precision of the C-14 dates. However, certain dates may show discrepancies w

  12. New hydroxyproline radiocarbon dates from Sungir, Russia, confirm early Mid Upper Palaeolithic burials in Eurasia.

    Science.gov (United States)

    Nalawade-Chavan, Shweta; McCullagh, James; Hedges, Robert

    2014-01-01

    Sungir (Russia) is a key Mid-Upper Palaeolithic site in Eurasia, containing several spectacular burials that disclose early evidence for complex burial rites in the form of a range of grave goods deposited along with the dead. Dating has been particularly challenging, with multiple radiocarbon dates ranging from 19,160±270 to 28,800±240 BP for burials that are believed to be closely similar in age. There are disparities in the radiocarbon dates of human bones, faunal remains and charcoal found on the floor of burials. Our approach has been to develop compound-specific methods using High Performance Liquid Chromatography (HPLC) to separate single amino acids, such as hydroxyproline, and thereby avoid the known human contamination on the bones themselves. Previously, we applied this technique to obtain radiocarbon dates of ∼30,000 BP for Sungir 2, Sungir 3 and a mammoth bone from the occupation levels of the site. The single amino acid radiocarbon dates were in good agreement with each other compared to all the dates previously reported, supporting their reliability. Here we report new hydroxyproline dates for two more human burials from the same site, Sungir 1 and Sungir 4. All five hydroxyproline dates reported are statistically indistinguishable and support an identical age for the group. The results suggest that compound-specific radiocarbon analysis should be considered seriously as the method of choice when precious archaeological remains are to be dated because they give a demonstrably contaminant-free radiocarbon age. The new ages are, together with the previously dated 'Red Lady of Paviland' human in the British Isles, the earliest for Mid Upper Palaeolithic burial behaviour in Eurasia, and point to the precocious appearance of this form of rite in Europe Russia.

  13. Establishing the date of Maori environmental impact in New Zealand through pollen analysis and radiocarbon dating

    Energy Technology Data Exchange (ETDEWEB)

    McGlone, M.S.; Wilmshurst, J.M. [Landcare Research, Lincoln, (New Zealand)

    1997-12-31

    Full text: Over the last decade there has been an intense debate about whether New Zealand prehistory is long ( > 1500 years) or short ( < 800 years). Pollen and charcoal analyses have played a key role in this debate by helping to pinpoint the transition from relatively undisturbed environments to those deforested by anthropogenic fires. Problems with in situ contamination, reworking of sediments, confusion of natural with anthropogenic impacts, and different theoretical expectations of growth, spread and impact of early Maori populations have led to disparate conclusions. We review pollen based studies carried out on a variety of fossil sites, including peat bogs, swamps, estuaries and lakes, and contribute new results. Different sedimentary environments show varying susceptibilities to contamination and have resulted in a wide spread of ages for initial Maori impact. Datable materials least susceptible to contamination by old or young carbon are pure peat and macrofossils, whereas lake, swamp and silty sediments are most susceptible. Analysis of the radiocarbon ages obtained for the start of Maori deforestation show that ages falling in the `long` prehistory period are exclusively derived from lake sediments and swamps. In contrast, the bulk of the ages falling in the `short` prehistory period are from pure peat and selected plant fragments. We conclude from our analysis of radiocarbon ages for pollen based deforestation that the first evidence of Maori environmental impact began about 700-550 calendar years BP (1250-1400 AD). Finer age resolution is limited by dating techniques, site limitations and the uncertainty associated with identifying the first signs of human impact. The period we have identified corresponds with the oldest dated archaeological sites and supports the short prehistory hypothesis. We discuss how to distinguish reliable fossil sites from those that have a high risk of giving misleading results.

  14. Radiocarbon dating of extinct fauna in the Americas recovered from tar pits

    Energy Technology Data Exchange (ETDEWEB)

    Jull, A.J.T. E-mail: jull@email.arizona.edu; Iturralde-Vinent, M.; O' Malley, J.M.; MacPhee, R.D.E.; McDonald, H.G.; Martin, P.S.; Moody, J.; Rincon, A

    2004-08-01

    We have obtained radiocarbon dates by accelerator mass spectrometry on bones of extinct large mammals from tar pits. Results on some samples of Glyptodon and Holmesina (extinct large mammals similar to armadillos) yielded ages of >25 and >21 ka, respectively. We also studied the radiocarbon ages of three different samples of bones from the extinct Cuban ground sloth, Parocnus bownii, which yielded dates ranging from 4960 {+-} 280 to 11 880 {+-} 420 yr BP. In order to remove the tar component pretreat the samples sufficiently to obtain reliable dates, we cleaned the samples by Soxhlet extraction in benzene. Resulting samples of collagenous material were often small.

  15. Radiocarbon dating of extinct fauna in the Americas recovered from tar pits

    Science.gov (United States)

    Jull, A. J. T.; Iturralde-Vinent, M.; O'Malley, J. M.; MacPhee, R. D. E.; McDonald, H. G.; Martin, P. S.; Moody, J.; Rincón, A.

    2004-08-01

    We have obtained radiocarbon dates by accelerator mass spectrometry on bones of extinct large mammals from tar pits. Results on some samples of Glyptodon and Holmesina (extinct large mammals similar to armadillos) yielded ages of >25 and >21 ka, respectively. We also studied the radiocarbon ages of three different samples of bones from the extinct Cuban ground sloth, Parocnus bownii, which yielded dates ranging from 4960 ± 280 to 11 880 ± 420 yr BP. In order to remove the tar component pretreat the samples sufficiently to obtain reliable dates, we cleaned the samples by Soxhlet extraction in benzene. Resulting samples of collagenous material were often small.

  16. Radiocarbon dating in near-Eastern contexts : Confusion and quality control

    NARCIS (Netherlands)

    van der Plicht, J; Bruins, HJ; Bruins, Hendrik J.; Boaretto, E.; Carmi, I.

    2001-01-01

    Near-Eastern archaeology has long remained oblivious to radiocarbon dating as unique historical calendars brought about a perception that C-14 dating is superfluous. Circular chronological reasoning may occur as a result. There is now strong C-14 evidence that the early part of Egyptian history seem

  17. What is the true age uncertainty of radiocarbon dated Holocene records?

    Science.gov (United States)

    Ho, Sze Ling; Groeneveld, Jeroen; Refeld, Kira; Mollenhauer, Gesine; De Pol-Holz, Ricardo; Nürnberg, Dirk; Laepple, Thomas

    2016-04-01

    Radiocarbon-based age-depth models are the backbone of the chronology of Holocene sediment records. The uncertainty of such age-depth models is often estimated from the uncertainty of the calibrated radiocarbon samples. A necessary assumption hereby is that the age of the samples is representative for the proxies in the same sediment layer they originate from. Here we generate radiocarbon and multiple temperature proxy data in three Holocene sediment cores from the same multi-corer employed in the Southwest Pacific. Surprisingly, whilst radiocarbon ages at the same sediment depth strongly differ between the tubes, multiple independent proxy time-series measured in each of the sediment cores suggest stratified sediments at the site. This is based on the finding that proxy time-series correlate significantly better between sediment cores when analyzed over depth, rather than against core-specific age-depth models based on the radiocarbon dates. If our site is not a pathological special case - an argument which we have no evidence for - our finding has important implications for age-depth modeling and the interpretations of paleoclimate time-series. It suggests that the true age uncertainty of a sediment layer can be much higher than the uncertainty obtained from the radiocarbon dates. An alternative but less likely hypothesis is that the proxy values are modified post-deposition in the sediments, resulting in more consistent stratification than the original climate signal time-series. Our study demonstrates the usefulness of replication of the proxy time series and radiocarbon dates in the quest for chronologic precision and proxy reliability, which are crucial for a more quantitative understanding of Holocene climate evolution.

  18. Radiocarbon dating of glacier ice: overview, optimisation, validation and potential

    Directory of Open Access Journals (Sweden)

    C. Uglietti

    2016-12-01

    of 10 000 years. WIOC 14C dating was not only crucial for interpretation of the embedded environmental and climatic histories, but additionally gave a better insight into glacier flow dynamics close to the bedrock and past glacier coverage. For this the availability of multiple dating points in the deepest parts was essential, which is the strength of the presented WIOC 14C dating method, allowing determination of absolute ages from principally every piece of ice.

  19. Analysis of Artificial Radiocarbon in Different Skeletal and Dental Tissue Types to Evaluate Date of Death

    Energy Technology Data Exchange (ETDEWEB)

    Ubelaker, D H; Buchholz, B A; Stewart, J

    2005-07-19

    Radiocarbon dating, with special reference to the modern bomb-curve, can provide useful information to elucidate the date of death of skeletonized human remains. Interpretation can be enhanced with analysis of different types of tissues within a single skeleton because of the known variability of formation times and remodeling rates. Analysis of radiocarbon content of teeth, especially the enamel in tooth crowns provides information about the date of formation in the childhood years and in consideration of the known timing of tooth formation can be used to estimate the birth date after 1950 A.D. Radiocarbon analysis of modern cortical and trabecular bone samples from the same skeleton may allow proper placement on the pre-1963 or post-1963 sides of the bomb-curve since most trabecular bone generally undergoes more rapid remodeling than does most cortical bone. Pre-1963 bone formation would produce higher radiocarbon values for most trabecular bone than for most cortical bone. This relationship is reversed for formation after 1963. Radiocarbon analysis was conducted in this study on dental, cortical and trabecular bone samples from two adult individuals of known birth (1925 and 1926) and death dates (1995 and 1959). As expected, the dental results correspond to pre-bomb bomb-curve values reflecting conditions during the childhoods of the individuals. The curve radiocarbon content of most bone samples reflected the higher modern bomb-curve values. Within the bone sample analyses, the values of the trabecular bone were higher than those of cortical bone and supported the known placement on the pre-1963 side of the bomb-curve.

  20. AMS {sup 14}C dating of early Anasazi petroglyphs from the North American southwest desert region

    Energy Technology Data Exchange (ETDEWEB)

    Beck, W.; Donahue, D.; Burr, G.; Jull, A.J.T. [Arizona State Univ., Tempe, AZ (United States). Dept. of Physics

    1997-12-31

    Full text: Since it was first developed in the early 1980`s, direct dating of rock surfaces by AMS radiocarbon analysis has become an integral tool in the fields of geomorphology and archaeology. Recently, the AMS Laboratory at the University of Arizona has become directly involved in a series of measurements in an attempt to determine the age of the petroglyphs found in the Petrified Forest region of NE Arizona, in the American Southwest. There are several generations of these petroglyphs, the most recent of these have been ascribed to the so-called Pueblo Indians which lived in this region between 700-1450 AD. Three earlier epochs of petroglyph makers also inhabited this region which have been grouped into the Basketmaker, Archaic, and Paleo-Indian periods. This original focus of this study was an attempt to identify the timing of development of the Paleo-Indian and Archaic Indian styles of petroglyphs from this region using AMS {sup 14}C measurements. Microscopic examination of samples from these petroglyphs, showed that the samples contained two types of black, carbon-rich materials with distinctly different visual properties. Detailed examination of these particles reveal that one type strongly resembles finely ground bituminous coal, whereas the other strongly resembles ground pyrolized wood. Subsequent measurements of the radiocarbon contents of separated fractions of the two types of materials have shown that they have widely differing radiocarbon ages. In such cases, the radiocarbon age of the entire sample would yield results which are, at best, ambiguous.

  1. Radiocarbon dating of prehistoric phytoliths: a preliminary study of archaeological sites in China

    OpenAIRE

    Xinxin Zuo; Houyuan Lu; Jianping Zhang; Can Wang; Guoping Sun; Yunfei Zheng

    2016-01-01

    Phytoliths can occlude some organic carbon during their deposition in plants. This carbon fraction is recognised as an ideal dating material because of its high resistance to decomposition and post-deposition contamination at the time of phytolith formation. However, the reliability of phytolith radiocarbon dating has recently been questioned. The development of a new extraction protocol for phytoliths, with paired dating between phytoliths and other materials from the same sediment, may prov...

  2. {sup 14}C AMS dating Yongcheon cave

    Energy Technology Data Exchange (ETDEWEB)

    Lee, J.H., E-mail: jefflee@snu.ac.kr [AMS Lab., NCIRF, Seoul National University, Seoul 151-742 (Korea, Republic of); Choe, K. [AMS Lab., NCIRF, Seoul National University, Seoul 151-742 (Korea, Republic of); Kim, J.C. [Dept. of Physics and Astronomy, Seoul National University, Seoul 151-742 (Korea, Republic of); Choi, S.H.; Kang, J.; Song, S.; Song, Y.M. [AMS Lab., NCIRF, Seoul National University, Seoul 151-742 (Korea, Republic of); Jang, J.G. [Jeju National Museum, Jeju 690-782 (Korea, Republic of)

    2013-01-15

    The biggest island in South Korea is Jeju Island, which lies 80 km south of the mainland and has one shield volcano, Mt. Halla. The volcanic island and its lava tubes were added to the world heritage list by UNESCO in 2007. Among the many lava tubes on the island, a unique cave had been accidentally found in 2005 while some workers were replacing a telephone pole. Until the discovery, it had been completely isolated from the outside by naturally-built sand blocks. Yongcheon cave is a lime-decorated lava tube showing both the properties of a volcanic lava tube and a limestone cave. This cave, about 3 km in length, is acknowledged to be the best of this type in the world and includes a large clean-water lake, lava falls, and richly developed speleothems inside it. Even though there is archaeological evidence from well preserved pottery that ancient people entered this place, the preservation of artifacts was ensured by a geological change that made later entrance difficult. We have collected charcoal samples scattered around the cave and dated them using AMS. Ages were in the range of ca. 1570-1260 BP (A.D. 340-880) and this corresponds to the Ancient Three Kingdoms and the Unified Silla era in Korean history. The {sup 14}C AMS measurement results presented in this paper on wood charcoal provide precise dates which will be very useful not only to clarify the nature of human activities in this cave but also to provide reference dates when comparing other dating methods.

  3. Radiocarbon dating of fluvial organic matter reveals land-use impacts in boreal peatlands

    DEFF Research Database (Denmark)

    Hulatt, Chris J.; Kaartokallio, Hermanni; Oinonen, Markku

    2014-01-01

    This study measured the effects of land use on organic matter released to surface waters in a boreal peat catchment using radiocarbon dating of particulate and dissolved organic carbon (POC and DOC), DOC concentration, stable carbon and nitrogen isotope composition, and optical measurements. Undi...

  4. The most direct and precise radiocarbon date for the Minoan eruption of Santorini

    DEFF Research Database (Denmark)

    Friedrich, Walter L.; Heinemeier, Jan

    for the Minoan eruption. Together with a second olive tree, excavated only 9 meters from the first one, it enables us to repeat the earlier measurements of the first tree 2006 (Friedrich, W.L . Kromer, B Friedrich, M. Heinemeier, J. Pfeiffer, T. Talamo, S. Santorini Eruption Radiocarbon Dated to 1627-1600 BC...

  5. The radiocarbon dating project at Aboriginal Affairs, Victoria

    Energy Technology Data Exchange (ETDEWEB)

    Godfrey, M.C.S. [La Trobe Univ., Bundoora, VIC (Australia). School of Chemistry

    1997-12-31

    The purpose of this project has been to publish a complete list of the age estimates relating to the archaeological sites in the State of Victoria from 1951 to 1995, and to assess the value and the limitations of this information for interpreting the prehistory of this region. This project has recorded 476 dates coming from 14 laboratories, and ranging in age from the time of European settlement to the limit of the technique at around 40,000 years BP. However, the available evidence indicates that large discrepancies may exist in these results, and this has lead to the recommendation that this data should not be used in research projects requiring dating accuracies of less than a few hundred years. Paper no. 34; 1 refs., 2 tabs.

  6. From 14C/12C measurements towards radiocarbon dating of ice

    NARCIS (Netherlands)

    Oerlemans, J.; Wal, R.S.W. van de; Roijen, J.J. van; Raynaud, D.; Borg, K. van der; Jong, A.F.M. de; Lipenkov, V.; Huybrechts, P.

    1994-01-01

    A dry extraction method of CO2 included in glacier ice adds a contamination equivalent to 1.8 μg modern carbon for a 35 μg C sample. This enables radiocarbon dating by accelerator mass spectrometry of 35 μg C samples to about 25 000 BP. Measured 14C/12C ratios are presented for a part of the Vostok

  7. Matanchen complex: new radiocarbon dates on early coastal adaptation in west Mexico.

    Science.gov (United States)

    Mountjoy, J B; Taylor, R E; Feldman, L H

    1972-03-17

    Samples of marine shell from archeological context on the coast of Nayarit, Mexico, have given radiocarbon determinations of 1810 +/- 80 B.C., 2000 +/- 100 B.C., and 2100 +/- 100 B.C. Even with maximum correction for upwelling these are the earliest dates for coastal occupation in West Mexico north of Acapulco, Guerrero. Analysis of the midden contents has provided new insights regarding early coastal adaptation.

  8. Rewriting the Central European Early Bronze Age Chronology: Evidence from Large-Scale Radiocarbon Dating.

    Science.gov (United States)

    Stockhammer, Philipp W; Massy, Ken; Knipper, Corina; Friedrich, Ronny; Kromer, Bernd; Lindauer, Susanne; Radosavljević, Jelena; Wittenborn, Fabian; Krause, Johannes

    2015-01-01

    The transition from the Neolithic to the Early Bronze Age in Central Europe has often been considered as a supra-regional uniform process, which led to the growing mastery of the new bronze technology. Since the 1920s, archaeologists have divided the Early Bronze Age into two chronological phases (Bronze A1 and A2), which were also seen as stages of technical progress. On the basis of the early radiocarbon dates from the cemetery of Singen, southern Germany, the beginning of the Early Bronze Age in Central Europe was originally dated around 2300/2200 BC and the transition to more complex casting techniques (i.e., Bronze A2) around 2000 BC. On the basis of 140 newly radiocarbon dated human remains from Final Neolithic, Early and Middle Bronze Age cemeteries south of Augsburg (Bavaria) and a re-dating of ten graves from the cemetery of Singen, we propose a significantly different dating range, which forces us to re-think the traditional relative and absolute chronologies as well as the narrative of technical development. We are now able to date the beginning of the Early Bronze Age to around 2150 BC and its end to around 1700 BC. Moreover, there is no transition between Bronze (Bz) A1 and Bronze (Bz) A2, but a complete overlap between the type objects of the two phases from 1900-1700 BC. We thus present a revised chronology of the assumed diagnostic type objects of the Early Bronze Age and recommend a radiocarbon-based view on the development of the material culture. Finally, we propose that the traditional phases Bz A1 and Bz A2 do not represent a chronological sequence, but regionally different social phenomena connected to the willingness of local actors to appropriate the new bronze technology.

  9. Radiocarbon dating of the Early Natufian at el-Wad Terrace, Mount Carmel, Israel

    Science.gov (United States)

    Eckmeier, E.; Yeshurun, R.; Weinstein-Evron, M.; Mintz, E.; Boaretto, E.

    2012-04-01

    The Natufian culture (15-11.5 kyr BP) of the Levant played an integral role in the transition from nomadic hunter-gatherers to the establishment of sedentism and, finally, to food producing societies of the Neolithic. The Natufian sites in the Southern Levant are characterised by a lack of macrobotanical remains, including charcoal, and a poor preservation of bone collagen. A result of the scarcity of radiocarbon dateable material is that only about 30 reliable radiocarbon dates from the Natufian are available for constructing a chronology of this period, which would enable a better synchronisation of archaeological and environmental data. A key question of Natufian research is if and to what extent past climate changes influenced the lifestyle of the Natufian communities, but the prerequisite for the correlation of cultural and environmental events in time are accurate chronologies. Therefore, a chronological framework with dates from well-defined contexts and samples of good quality is essential for the investigation of the Natufian. We present new C-14 data from the site of el-Wad Terrace, one of the major Natufian hamlets of the 'core area' of this culture. The samples (12 charcoals and 34 bones, of which 6 charcoals and 5 bones were suitable for dating) were derived from Early Natufian (15-13 kyr BP) living surfaces, dwellings and burials. Using FTIR, we investigated the environmental factors that influenced the preservation of material for radiocarbon dating of the site, and we tested a modified pre-treatment method for poorly preserved charcoal samples. We found that the usual pre-treatment protocol for C-14 samples (W-ABA) removed more charcoal material than the method modified by Rebollo et al. (2008) which omits the first acid treatment (W-BA). This first acid step enhanced the extraction of humic substances during the subsequent base step. The modified W-BA method is a promising tool for dating poorly preserved charcoals which needs further testing with

  10. Correlating the ancient Maya and modern European calendars with high-precision AMS 14C dating.

    Science.gov (United States)

    Kennett, Douglas J; Hajdas, Irka; Culleton, Brendan J; Belmecheri, Soumaya; Martin, Simon; Neff, Hector; Awe, Jaime; Graham, Heather V; Freeman, Katherine H; Newsom, Lee; Lentz, David L; Anselmetti, Flavio S; Robinson, Mark; Marwan, Norbert; Southon, John; Hodell, David A; Haug, Gerald H

    2013-01-01

    The reasons for the development and collapse of Maya civilization remain controversial and historical events carved on stone monuments throughout this region provide a remarkable source of data about the rise and fall of these complex polities. Use of these records depends on correlating the Maya and European calendars so that they can be compared with climate and environmental datasets. Correlation constants can vary up to 1000 years and remain controversial. We report a series of high-resolution AMS (14)C dates on a wooden lintel collected from the Classic Period city of Tikal bearing Maya calendar dates. The radiocarbon dates were calibrated using a Bayesian statistical model and indicate that the dates were carved on the lintel between AD 658-696. This strongly supports the Goodman-Martínez-Thompson (GMT) correlation and the hypothesis that climate change played an important role in the development and demise of this complex civilization.

  11. NON-DESTRUCTIVE RADIOCARBON DATING: NATURALLY MUMMIFIED INFANT BUNDLE FROM SW TEXAS

    Energy Technology Data Exchange (ETDEWEB)

    Steelman, K L; Rowe, M W; Turpin, S A; Guilderson, T P; Nightengale, L

    2004-09-07

    Plasma oxidation was used to obtain radiocarbon dates on six different materials from a naturally mummified baby bundle from the Lower Pecos River region of southwest Texas. This bundle was selected because it was thought to represent a single event and would illustrate the accuracy and precision of the plasma oxidation method. Five of the materials were clearly components of the original bundle with 13 dates combined to yield a weighted average of 2135 {+-} 11 B.P. Six dates from a wooden stick of Desert Ash averaged 939 {+-} 14 B.P., indicating that this artifact was not part of the original burial. Plasma oxidation is shown to be a virtually non-destructive alternative to combustion. Because only sub-milligram amounts of material are removed from an artifact over its exposed surface, no visible change in fragile materials has been observed, even under magnification. The method is best applied when natural organic contamination is unlikely and serious consideration of this issue is needed in all cases. If organic contamination is present, it will have to be removed before plasma oxidation to obtain accurate radiocarbon dates.

  12. Radiocarbon dates for beeswax figures in the prehistoric rock art of northern Australia

    Energy Technology Data Exchange (ETDEWEB)

    Nelson, D.E. [Simon Fraser Univ., Burnaby, BC (Canada). Dept. of Archaeology; Chaloupka, G. [Northern Territory Museum, Darwin, NT (Australia); Chippindale, C. [Cambridge Univ. Museum (United Kingdom); Alderson, M.S. [Australian Nature Conservation Agency, Jabiru, NT (Australia). Kakadu National Park; Southon, J.R. [Lawrence Livermore National Lab., CA (United States)

    1995-02-01

    Accelerator mass spectrometry radiocarbon ages have been taken for a test suite of small samples of material removed from some of the ``beeswax`` art figures found in rock shelters in northern Australia. The results indicate that we can reliably date this unique form of rock art with no noticeable damage. We had not expected to find figures of any great antiquity, and so were surprised to find that the ages obtained spanned the time period from the recent past to about 4000 BP. (Author).

  13. Comparative radiocarbon dating of lignite, pottery, and charcoal samples from Babeldaob Island, Republic of Palau

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, A.; Chappell, J.; Clark, G.; Phear, S. [Australian National University, Canberra, ACT (Australia)

    2005-07-01

    It is difficult to construct archaeological chronologies for Babeldaob, the main island of Palau (western Micronesia), because the saprolitic clays of the dominant terraced-hill sites and associated ceramic sherds often contain old carbon that originated in lignites. This has implications, as well, for chronologies of sedimentary sequences. Comparative analysis of the dating problem using lignite, pottery, and charcoal samples indicates that, in fact, there are both old and young sources of potential contamination. It is concluded that radiocarbon samples from Babeldaob need to be tested for appropriate carbon content rather than relying solely upon material identification.

  14. Prehistoric peyote use: alkaloid analysis and radiocarbon dating of archaeological specimens of Lophophora from Texas.

    Science.gov (United States)

    El-Seedi, Hesham R; De Smet, Peter A G M; Beck, Olof; Possnert, Göran; Bruhn, Jan G

    2005-10-01

    Two archaeological specimens of peyote buttons, i.e. dried tops of the cactus Lophophora williamsii (Lem.) Coulter, from the collection of the Witte Museum in San Antonio, was subjected to radiocarbon dating and alkaloid analysis. The samples were presumably found in Shumla Cave No. 5 on the Rio Grande, Texas. Radiocarbon dating shows that the calibrated 14C age of the weighted mean of the two individual dated samples corresponds to the calendric time interval 3780-3660 BC (one sigma significance). Alkaloid extraction yielded approximately 2% of alkaloids. Analysis with thin-layer chromatography (TLC) and gas chromatography-mass spectrometry (GC-MS) led to the identification of mescaline in both samples. No other peyote alkaloids could be identified. The two peyote samples appear to be the oldest plant drug ever to yield a major bioactive compound upon chemical analysis. The identification of mescaline strengthens the evidence that native North Americans recognized the psychotropic properties of peyote as long as 5700 years ago.

  15. Radiocarbon dating late Quaternary loess deposits using small terrestrial gastropod shells

    Science.gov (United States)

    Pigati, Jeff S.; McGeehin, John P.; Muhs, Daniel R.; Bettis, E. Arthur

    2013-01-01

    Constraining the ages and mass accumulation rates of late Quaternary loess deposits is often difficult because of the paucity of organic material typically available for 14C dating and the inherent limitations of luminescence techniques. Radiocarbon dating of small terrestrial gastropod shells may provide an alternative to these methods as fossil shells are common in loess and contain ∼12% carbon by weight. Terrestrial gastropod assemblages in loess have been used extensively to reconstruct past environmental conditions but have been largely ignored for dating purposes. Here, we present the results of a multi-faceted approach to understanding the potential for using small terrestrial gastropod shells to date loess deposits in North America. First, we compare highly resolved 14C ages of well-preserved wood and gastropod shells (Succineidae) recovered from a Holocene loess section in Alaska. Radiocarbon ages derived from the shells are nearly identical to wood and plant macrofossil ages throughout the section, which suggests that the shells behaved as closed systems with respect to carbon for at least the last 10 ka (thousands of calibrated 14C years before present). Second, we apply 14C dating of gastropod shells to late Pleistocene loess deposits in the Great Plains using stratigraphy and independent chronologies for comparison. The new shell ages require less interpretation than humic acid radiocarbon ages that are commonly used in loess studies, provide additional stratigraphic coverage to previous dating efforts, and are in correct stratigraphic order more often than their luminescence counterparts. Third, we show that Succineidae shells recovered from historic loess in the Matanuska River Valley, Alaska captured the 20th century 14C bomb spike, which suggests that the shells can be used to date late Holocene and historic-aged loess. Finally, results from Nebraska and western Iowa suggest that, similar to other materials, shell ages approaching ∼40 ka should

  16. Radiocarbon dating of prehistoric phytoliths: a preliminary study of archaeological sites in China.

    Science.gov (United States)

    Zuo, Xinxin; Lu, Houyuan; Zhang, Jianping; Wang, Can; Sun, Guoping; Zheng, Yunfei

    2016-05-26

    Phytoliths can occlude some organic carbon during their deposition in plants. This carbon fraction is recognised as an ideal dating material because of its high resistance to decomposition and post-deposition contamination at the time of phytolith formation. However, the reliability of phytolith radiocarbon dating has recently been questioned. The development of a new extraction protocol for phytoliths, with paired dating between phytoliths and other materials from the same sediment, may provide further evidence for the reliability of phytolith dating. We present an improved method for extracting phytoliths from soils. We compared the dating of phytoliths and other materials (e.g., charcoal and plant seeds) recovered at the same depth from seven pits at six archaeological sites in China. The estimated ages of the phytoliths and other materials were generally consistent, except for one outlier. We attribute this inconsistency to the post-depositional processes of phytoliths in soil, rather than to the uptake of old carbon from the soil. Our results clearly show the potential for phytolith carbon dating at archaeological sites in the absence of other dating materials.

  17. Comparison of sampling methods for radiocarbon dating of carbonyls in air samples via accelerator mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Schindler, Matthias, E-mail: matthias.schindler@physik.uni-erlangen.de; Kretschmer, Wolfgang; Scharf, Andreas; Tschekalinskij, Alexander

    2016-05-15

    Three new methods to sample and prepare various carbonyl compounds for radiocarbon measurements were developed and tested. Two of these procedures utilized the Strecker synthetic method to form amino acids from carbonyl compounds with either sodium cyanide or trimethylsilyl cyanide. The third procedure used semicarbazide to form crystalline carbazones with the carbonyl compounds. The resulting amino acids and semicarbazones were then separated and purified using thin layer chromatography. The separated compounds were then combusted to CO{sub 2} and reduced to graphite to determine {sup 14}C content by accelerator mass spectrometry (AMS). All of these methods were also compared with the standard carbonyl compound sampling method wherein a compound is derivatized with 2,4-dinitrophenylhydrazine and then separated by high-performance liquid chromatography (HPLC).

  18. Comparison of sampling methods for radiocarbon dating of carbonyls in air samples via accelerator mass spectrometry

    Science.gov (United States)

    Schindler, Matthias; Kretschmer, Wolfgang; Scharf, Andreas; Tschekalinskij, Alexander

    2016-05-01

    Three new methods to sample and prepare various carbonyl compounds for radiocarbon measurements were developed and tested. Two of these procedures utilized the Strecker synthetic method to form amino acids from carbonyl compounds with either sodium cyanide or trimethylsilyl cyanide. The third procedure used semicarbazide to form crystalline carbazones with the carbonyl compounds. The resulting amino acids and semicarbazones were then separated and purified using thin layer chromatography. The separated compounds were then combusted to CO2 and reduced to graphite to determine 14C content by accelerator mass spectrometry (AMS). All of these methods were also compared with the standard carbonyl compound sampling method wherein a compound is derivatized with 2,4-dinitrophenylhydrazine and then separated by high-performance liquid chromatography (HPLC).

  19. Radiocarbon dating of silica sinter deposits in shallow drill cores from the Upper Geyser Basin, Yellowstone National Park

    Science.gov (United States)

    Lowenstern, Jacob B.; Hurwitz, Shaul; McGeehin, John

    2016-01-01

    To explore the timing of hydrothermal activity at the Upper Geyser Basin (UGB) in Yellowstone National Park, we obtained seven new accelerator mass spectrometry (AMS) radiocarbon 14C ages of carbonaceous material trapped within siliceous sinter. Five samples came from depths of 15–152 cm within the Y-1 well, and two samples were from well Y-7 (depths of 24 cm and 122 cm). These two wells, at Black Sand and Biscuit Basins, respectively, were drilled in 1967 as part of a scientific drilling program by the U.S. Geological Survey (White et al., 1975). Even with samples as small as 15 g, we obtained sufficient carbonaceous material (a mixture of thermophilic mats, pollen, and charcoal) for the 14C analyses. Apparent time of deposition ranged from 3775 ± 25 and 2910 ± 30 14C years BP at the top of the cores to about 8000 years BP at the bottom. The dates are consistent with variable rates of sinter formation at individual sites within the UGB over the Holocene. On a basin-wide scale, though, these and other existing 14C dates hint that hydrothermal activity at the UGB may have been continuous throughout the Holocene.

  20. Radiocarbon dates on cave bear (Ursus spelaeus) and brown bear (Ursus arctos) from Late Pleistocene of Poland

    Science.gov (United States)

    Nadachowski, Adam; Lipecki, Grzegorz; Stefaniak, Krzysztof; Wojtal, Piotr

    2010-05-01

    Although cave bear (Ursus spelaeus) is far more abundant in last glacial in Europe than brown bear (Ursus arctos), the co-occurrence of both species during Oxygen Isotope Stage 3 (OIS 3) is not questioned. The cave bear (Ursus spelaeus) has been an important part of the European large mammal fauna of last glaciation. Most of the remains come from karst areas where larger caves were used as hibernation sites. In Poland caves occur in the Sudetes Mts, Kraków-Częstochowa Upland, Świętokrzyskie Mts and in the Carpathians (especially in Tatra and Pieniny Mts). The AMS 14C dates were obtained for 14 sites (23 dates) distributed in all karst areas of Poland. All samples dated in Poznań Radiocarbon Laboratory (Poz) were subject of pre-treatment procedures (ultrafiltration and removal of consolidants). Dates are given as an uncalibrated radiocarbon dates (BP) and as calendar dates (cal. BP). The Eastern Sudetes sites are represented by two cave bear remains from Niedźwiedzia Cave, Kletno. Most of samples come from several localities located in different parts of Kraków-Częstochowa Upland (Nietoperzowa, Mamutowa, Ciemna, Wylotne and Zawalona caves - all near Kraków; Komarowa, Deszczowa, Stajnia and Niedźwiedzia near Olsztyn caves - all from the middle part of the Upland). Raj Cave is located in Świętokrzyskie Mts. The Carpathians samples come from two caves in Tatra Mts: Magurska and Poszukiwaczy Skarbów. Results obtained suggest that in the early part of OIS 3, ca. 50-33 ka (ca. 54-37,5 cal. ka), when the climate was relatively stable and warm, cave bears occurred probably more or less continuously from Sudetes Mts to Kraków-Częstochowa Upland and in the Carpathians. The available 18 dates range from >52,000 BP (Poz-24205) to 33,000±400 BP (Poz-23655) (cal. 38,571±1,449 BP). Around 33 ka BP (cal. 38,5 ka BP) cave bears probably disappeared, or at least reduced their number, in the area north from Sudetes and the Carpathians for next ca. 4-5 millennia

  1. Direct radiocarbon dates for prehistoric paintings at the Altamira, El Castillo and Niaux caves

    Energy Technology Data Exchange (ETDEWEB)

    Valladas, H.; Cachier, H.; Maurice, P.; Arnold, M. (Centre National de la Recherche Scientifique (CNRS), 91 - Gif-sur-Yvette (France)); Quiros, F.B. de (Universidad de Leon (Spain). Area de Prehistoria); Clottes, J. (Ministere de la Culture et de la Communication, Foix (France)); Valdes, V.C. (UNED, Madrid (Spain). Departmento de Prehistoria e Historia Antigua); Uzquiano, P. (Centre National de la Recherche Scientifique (CNRS), 34 -Montpellier (France). Laboratoire de Paleobotanique)

    1992-05-07

    Among things that most strikingly distinguish modern humans from other hominids and the rest of the animal kingdom is the ability to represent things and events pictorially. Complex paintings of the type discovered in the Altamira, El Castillo, Niaux and Lascaux caves represent an important stepping stone in the cultural evolution of humankind. Until now dates were derived from style or dated remains left by prehistoric visitors and could be biased by prolonged occupation or visits unrelated to painting activity. Here we report the first radiocarbon dates for the charcoal used to draw stylistically similar bisons in these caves: 14,000 {+-} 400 yr BP in the Spanish caves of Altamira, 12,990 {+-} 200 yr BP in El Castillo, and 12,890 {+-} 160 yr BP for a bison of different style in the French Pyrenean cave of Niaux. Our results demonstrate the imprecise nature of stylistic dating and show that painting dates derived from remains of human activities should be used with caution. (Author).

  2. Radiocarbon dating of prehistoric rock paintings by selective oxidation of organic carbon

    Energy Technology Data Exchange (ETDEWEB)

    Russ, J.; Hyman, M.; Shafer, H.J.; Rowe, M.W. (Texas A and M Univ., College Station, TX (USA))

    1990-12-27

    Dating of prehistoric rock paintings (pictographs) has traditionally relied on indirect evidence. This includes inferences based on the archaeological context, such as superpositions of pictorial styles and the depiction of images that constrain their ages, as well as dating of deposits that either cover the art in situ or contain separated fragments of the painted surface. Migration of ions between the bulk rock and the natural coatings that form on a newly exposed surface has also been exploited to date petroglyphs (rock carvings) in desert regions. Until recently, however, direct dating (by radiocarbon techniques) of pictographs has not been possible, mainly because of the problem of separating inorganic carbon from the organic material in the pigments. Here we report on a new technique which allows this separation to be effected by using a low-temperature, low-pressure oxygen plasma to oxidize selectively the organic component; this may then be analysed using standard {sup 14}C methods. We have applied this technique to a portion of a pictograph from the Lower Pecos region of southwest Texas. The date obtained, 3,865{plus minus}100 yr BP (before present) is consistent with that expected on the basis of archaeological inference. As organic carbon is a ubiquitous component of pictograph paints, this technique should be applicable to rock paintings throughout the world. (author).

  3. AMS radiocarbon age for fossil bone by XAD-2 chromatography method

    Science.gov (United States)

    Minami, Masayo; Nakamura, Toshio

    2000-10-01

    The XAD-2 chromatography method was examined for its ability to efficiently eliminate exogenous organic matter from fossil bones and to improve the accuracy of radiocarbon ( 14C) dating and stable isotope determinations on bone proteins. The fossil bones used in the experiment were animal fossil bones collected from the Awazu submarine archaeological site, Shiga, Japan. For comparison, the gelatin-extraction method was also applied to the same samples. It was found that the gelatin-extraction method is sufficient for 14C dating on well-preserved bones, but insufficient on poorly preserved bones, containing less than 1% extractable gelatin. The XAD-2 resin is useful for the clean up of proteins especially from poorly preserved bones. The carbon stable isotope fractionation of around 1‰ by XAD-2 treatment on modern collagen standards was larger than reported previously. The isotopic variation by sequential extraction of bones probably originates from changes in the amino acid composition and seems to be less sensitive to the indication of the removal of organic contamination.

  4. Late Pleistocene Holocene stratigraphy and radiocarbon dating of La Malinche volcano, Central Mexico

    Science.gov (United States)

    Castro-Govea, Renato; Siebe, Claus

    2007-04-01

    Previous studies of La Malinche identified and radiocarbon dated several volcanic layers, the youngest of which yielded an age of ca. 7.5 ka. An additional ash fallout layer that crops out at high altitudes was considered the most recent deposit, with an estimated age of 6 ka. In the present work 38 new radiocarbon ages are presented. From these, several date the young ash fallout layer and lie around 3.1 ka. With the aid of these dates a new and comprehensive stratigraphy documenting the Late Pleistocene-Holocene eruptive history of La Malinche is presented. The stratigraphy indicates two main stages of volcanic activity: Pre-Malinche and Malinche. The first undoubtedly comprises the major part of the eruptive history, but its deposits are largely covered by the products of the latter stage, on which this study is focused. The Malinche stage was subdivided into three eruptive periods. Period 1 started with the emplacement of the Huamantla Pumice more than 45 ka ago. This deposit consists of a thick pumice fallout overlain by pyroclastic flow deposits. Subsequently, several episodes of construction and collapse of summit domes occurred. The oldest dome was dated at ca. 45 ka. Period 2 started 21.5 ka ago with the Malinche Pumice I, a widespread pumice fallout covering the entire slopes of the volcano. Pyroclastic flows and lahars related to this eruption were channeled along deep barrancas and reached considerable distances. Deposits produced by partial sector collapse and dated at ca. 20.9 ka, and a pumice-and-ash flow deposit dated at 15.9 ka were also generated during this period. The last period started with the eruption of the Malinche Pumice II, a distinctive fallout deposit overlain by ash flow deposits on the NE slope of the volcano. The age of this pumice layer is estimated between 12 and 9 ka. Formation of block-and-ash flows, lahars and pumice-and-ash flows followed during this period, and peaked in a most intensive episode that was dated at 7.5 ka

  5. Effects of sample mass and macrofossil type on radiocarbon dating of arctic and boreal lake sediments

    Energy Technology Data Exchange (ETDEWEB)

    Oswald, W W; Anderson, P M; Brown, T A; Brubaker, L B; Hu, F S; Lozhkin, A V; Tinner, W; Kaltenrieder, P

    2006-05-29

    Dating lake sediments by accelerator mass spectrometry (AMS) {sup 14}C analysis of plant macrofossils overcomes one of the main problems associated with dating bulk sediment samples, the presence of old organic matter. Even so, many AMS dates from arctic and boreal sites appear to misrepresent the age of the sediment. To understand the nature of these apparent dating anomalies better, we conducted a series of {sup 14}C dating experiments using samples from Alaskan and Siberian lake-sediment cores. First, to test whether our analytical procedures introduced a sample-mass bias, we obtained {sup 14}C dates for different-sized pieces of single woody macrofossils. In these sample-mass experiments, sized statistically equivalent ages were found for samples as small as 0.05 mg C. Second, to assess whether macrofossil type influenced dating results, we conducted sample-type experiments in which {sup 14}C dates were obtained for different macrofossil types sieved from the same depth in the sediment. We dated materials from multiple levels in sediment cores from Upper Capsule Lake (North Slope, northern Alaska) and Grizzly Lake (Copper River Basin, southern Alaska), and from single depths in other records from northern Alaska. In several of the experiments there were significant discrepancies between dates for different plant tissues, and in most cases wood and charcoal were older than other macrofossil types, usually by several hundred years. This pattern suggests that {sup 14}C dates for woody macrofossils may misrepresent the age of the sediment by centuries, perhaps due to their longer terrestrial residence time and the potential in-built age of long-lived plants. This study identifies why some {sup 14}C dates appear to be inconsistent with the overall age-depth trend of a lake-sediment record, and it may guide the selection of {sup 14}C samples in future studies.

  6. Radiocarbon-dating and ancient DNA reveal rapid replacement of extinct prehistoric penguins

    Science.gov (United States)

    Rawlence, Nicolas J.; Perry, George L. W.; Smith, Ian W. G.; Scofield, R. Paul; Tennyson, Alan J. D.; Matisoo-Smith, Elizabeth A.; Boessenkool, Sanne; Austin, Jeremy J.; Waters, Jonathan M.

    2015-03-01

    Prehistoric faunal extinctions dramatically reshaped biological assemblages around the world. However, the timing of such biotic shifts is often obscured by the fragmentary nature and limited temporal resolution of fossil records. We use radiocarbon-dating and ancient-DNA analysis of prehistoric (ca A.D. 1450-1834) Megadyptes penguin specimens to assess the time-frame of biological turnover in coastal New Zealand following human settlement. These data suggest that the final extirpation of the endemic Megadyptes waitaha, and subsequent replacement by the previously sub-Antarctic-limited Megadyptes antipodes, likely occurred within a narrow temporal window (e.g. a century or less). This transition represents one of the most rapid prehistoric faunal turnover events documented, and is likely linked to human demographic and cultural transitions during the 15th Century. Our results suggest that anthropogenic forces can trigger rapid biogeographic shifts.

  7. Radiocarbon dating of the human eye lens crystallines reveal proteins without carbon turnover throughout life

    DEFF Research Database (Denmark)

    Lynnerup, Niels; Kjeldsen, Henrik; Heegaard, Steffen

    2008-01-01

    , there is no subsequent remodelling of these fibers, nor removal of degraded lens fibers. Human tissue ultimately derives its (14)C content from the atmospheric carbon dioxide. The (14)C content of the lens proteins thus reflects the atmospheric content of (14)C when the lens crystallines were formed. Precise radiocarbon...... on a yearly basis this allows very accurate dating. METHODOLOGY/PRINCIPAL FINDINGS: Our results allow us to conclude that the crystalline formation in the lens nucleus almost entirely takes place around the time of birth, with a very small, and decreasing, continuous formation throughout life. The close...... that the eye lens is a soft structure, subjected to almost continuous deformation, due to lens accommodation, yet its most important constituent, the lens crystalline, is never subject to turnover or remodelling once formed. The determination of the (14)C content of various tissues may be used to assess...

  8. Radiocarbon dating and wood density chronologies of mangrove trees in arid Western Australia.

    Directory of Open Access Journals (Sweden)

    Nadia S Santini

    Full Text Available Mangrove trees tend to be larger and mangrove communities more diverse in tropical latitudes, particularly where there is high rainfall. Variation in the structure, growth and productivity of mangrove forests over climatic gradients suggests they are sensitive to variations in climate, but evidence of changes in the structure and growth of mangrove trees in response to climatic variation is scarce. Bomb-pulse radiocarbon dating provides accurate dates of recent wood formation and tree age of tropical and subtropical tree species. Here, we used radiocarbon techniques combined with X-ray densitometry to develop a wood density chronology for the mangrove Avicennia marina in the Exmouth Gulf, Western Australia (WA. We tested whether wood density chronologies of A. marina were sensitive to variation in the Pacific Decadal Oscillation Index, which reflects temperature fluctuations in the Pacific Ocean and is linked to the instrumental rainfall record in north WA. We also determined growth rates in mangrove trees from the Exmouth Gulf, WA. We found that seaward fringing A. marina trees (~10 cm diameter were 48 ± 1 to 89 ± 23 years old (mean ± 1 σ and that their growth rates ranged from 4.08 ± 2.36 to 5.30 ± 3.33 mm/yr (mean ± 1 σ. The wood density of our studied mangrove trees decreased with increases in the Pacific Decadal Oscillation Index. Future predicted drying of the region will likely lead to further reductions in wood density and their associated growth rates in mangrove forests in the region.

  9. Radiocarbon dating and wood density chronologies of mangrove trees in arid Western Australia.

    Science.gov (United States)

    Santini, Nadia S; Hua, Quan; Schmitz, Nele; Lovelock, Catherine E

    2013-01-01

    Mangrove trees tend to be larger and mangrove communities more diverse in tropical latitudes, particularly where there is high rainfall. Variation in the structure, growth and productivity of mangrove forests over climatic gradients suggests they are sensitive to variations in climate, but evidence of changes in the structure and growth of mangrove trees in response to climatic variation is scarce. Bomb-pulse radiocarbon dating provides accurate dates of recent wood formation and tree age of tropical and subtropical tree species. Here, we used radiocarbon techniques combined with X-ray densitometry to develop a wood density chronology for the mangrove Avicennia marina in the Exmouth Gulf, Western Australia (WA). We tested whether wood density chronologies of A. marina were sensitive to variation in the Pacific Decadal Oscillation Index, which reflects temperature fluctuations in the Pacific Ocean and is linked to the instrumental rainfall record in north WA. We also determined growth rates in mangrove trees from the Exmouth Gulf, WA. We found that seaward fringing A. marina trees (~10 cm diameter) were 48 ± 1 to 89 ± 23 years old (mean ± 1 σ) and that their growth rates ranged from 4.08 ± 2.36 to 5.30 ± 3.33 mm/yr (mean ± 1 σ). The wood density of our studied mangrove trees decreased with increases in the Pacific Decadal Oscillation Index. Future predicted drying of the region will likely lead to further reductions in wood density and their associated growth rates in mangrove forests in the region.

  10. Sun, Ocean, Nuclear Bombs, and Fossil Fuels: Radiocarbon Variations and Implications for High-Resolution Dating

    Science.gov (United States)

    Dutta, Koushik

    2016-06-01

    Radiocarbon, or 14C, is a radiometric dating method ideally suited for providing a chronological framework in archaeology and geosciences for timescales spanning the last 50,000 years. 14C is easily detectable in most common natural organic materials and has a half-life (5,730±40 years) relevant to these timescales. 14C produced from large-scale detonations of nuclear bombs between the 1950s and the early 1960s can be used for dating modern organic materials formed after the 1950s. Often these studies demand high-resolution chronology to resolve ages within a few decades to less than a few years. Despite developments in modern, high-precision 14C analytical methods, the applicability of 14C in high-resolution chronology is limited by short-term variations in atmospheric 14C in the past. This article reviews the roles of the principal natural drivers (e.g., solar magnetic activity and ocean circulation) and the anthropogenic perturbations (e.g., fossil fuel CO2 and 14C from nuclear and thermonuclear bombs) that are responsible for short-term 14C variations in the environment. Methods and challenges of high-resolution 14C dating are discussed.

  11. Rapidly Melting Ice Caps of Northern Baffin Island: Insights From Cosmogenic and Conventional Radiocarbon Dating

    Science.gov (United States)

    Anderson, R. K.; Miller, G. H.; Briner, J. P.; Lifton, N.; Devogel, S. B.

    2006-12-01

    The interior plateau of northern Baffin Island in the eastern Canadian Arctic is home to several small (history on the plateau since deglaciation 6 ka, several techniques have been used in concert. The recent extent of the ice caps during the Little Ice Age can be estimated from the preservation of lichen trimlines across much of the plateau. These trimlines represent previous multi-year snow or ice cover and their aerial extent can be measured via satellite imagery. Based on these measurements, modern ice caps represent only ~3% of ice-cap extent during the Little Ice Age. Radiocarbon dating of moss, preserved beneath the ice caps due to their cold-based nature, suggests a sudden expansion of ice cover around 520 calendar years before present (cal BP), indicated by a mode of 7 dates of approximately this age. This coincides with a pulse of global volcanic activity; predicted cooling from increased aerosol loading may have triggered rapid ice-cap growth. However, dead moss emerging at three sites is more than 1000 years old, with a maximum age of 1326±15 cal BP, indicating that portions of the remaining ice caps have remained intact from more than 1000 years Further constraints on ice cap size are provided by 14C cosmogenic exposure dating. 14C concentrations in rocks at the modern ice margin are too low to be the result of continuous exposure since deglaciation followed by shielding for 500-1000 years by ice cover. Exposure history modeling indicates at least one additional prior period of ice cover of approximately 1000 years. This cold interval most likely occurred sometime since 4 ka, after the Holocene Thermal Maximum in the Arctic and coeval with the onset of Neoglaciation. Radiocarbon dating reveals that some plateau ice caps have been continuously present for more than 1000 years, whereas others formed early in the Little Ice Age (~520 cal BP). Even without additional warming, continuation of current climatic conditions on northern Baffin Island will

  12. Direct radiocarbon dating and genetic analyses on the purported Neanderthal mandible from the Monti Lessini (Italy).

    Science.gov (United States)

    Talamo, Sahra; Hajdinjak, Mateja; Mannino, Marcello A; Fasani, Leone; Welker, Frido; Martini, Fabio; Romagnoli, Francesca; Zorzin, Roberto; Meyer, Matthias; Hublin, Jean-Jacques

    2016-07-08

    Anatomically modern humans replaced Neanderthals in Europe around 40,000 years ago. The demise of the Neanderthals and the nature of the possible relationship with anatomically modern humans has captured our imagination and stimulated research for more than a century now. Recent chronological studies suggest a possible overlap between Neanderthals and anatomically modern humans of more than 5,000 years. Analyses of ancient genome sequences from both groups have shown that they interbred multiple times, including in Europe. A potential place of interbreeding is the notable Palaeolithic site of Riparo Mezzena in Northern Italy. In order to improve our understanding of prehistoric occupation at Mezzena, we analysed the human mandible and several cranial fragments from the site using radiocarbon dating, ancient DNA, ZooMS and isotope analyses. We also performed a more detailed investigation of the lithic assemblage of layer I. Surprisingly we found that the Riparo Mezzena mandible is not from a Neanderthal but belonged to an anatomically modern human. Furthermore, we found no evidence for the presence of Neanderthal remains among 11 of the 13 cranial and post-cranial fragments re-investigated in this study.

  13. Preceramic, Aceramic or Early Ceramic? The radiocarbon dated beginning of the Neolithic in the Aegean

    Directory of Open Access Journals (Sweden)

    Agathe Reingruber

    2015-12-01

    Full Text Available The Pre-Pottery-Neolithic refers to a period in the Eastern Mediterranean when ceramic containers were not yet in use (although small objects made of clay were already being created. This concept, which reflects a specific and quite unique stage in the development of human history, was introduced to Aegean prehistory under the term of Preceramic during the 1950’s (e.g., in Argissa Magoula and Sesklo. Shortly thereafter, a different term, the Aceramic, was applied in the Aegean (e.g., in Knossos for levels devoid of pottery, although ceramic products were supposedly used in the wider region. In some cases, the thin levels interpreted as Preceramic or as Aceramic contained sherds that were regarded as being intrusive from above (e.g., Argissa-Magoula, Franchthi Cave. The new sequences of radiocarbon dates allow a more precise description of this early period and thereby contribute, not least, also to the clarification of terminological issues.

  14. Dynamics of nival and glacial slope processes in the Baksan and Teberda river basins from radiocarbon dating of buried soils

    Directory of Open Access Journals (Sweden)

    O. N. Solomina

    2013-01-01

    Full Text Available Radiocarbon and tree-ring dating of the soil horizons, buried in the slope and fluvioglacial deposits in Baksan and Teberda valleys, bring evidence of the reduction of the avalanche activity, stabilization of the slopes and soil formation on their surfaces. In the Baksan section three such horizons are identified, while in the Teberda section only one. The radiocarbon dates of the two thickest soil horizons in the Baksan section are 170±50 BP (1650–1890 CE and 380±60 BP (1430–1650 CE. The dendrochronological date of the wood (after 1677 in the upper layer of the buried soil horizon in the in the Dombai section probably indicate the increase of the river runoff and debris flow activity in relation with the glacier advance in the upperstream of Ammanauz river. However it is also close to the Terskoye earth quake occurred in 1688. The radiocarbon dates of the buried soils cluster in three groups (270–290, 340–440, 1280–1440 yrs BP. It is possible that their burial is connected to the climatic (increase in precipitation, especially extreme ones or seismic causes.

  15. AMS dating of early shellmounds of the Southeastern Brazilian coast

    Energy Technology Data Exchange (ETDEWEB)

    Lima, T. A. [Universidade Federal, Rio de Janeiro (UFRJ), RJ (Brazil). Museu Nacional. Dept. de Antropologia; Macario, K.D.; Anjos, R.M.; Gomes, P.R.S. [Universidade Federal Fluminense (UFF), Niteroi, RJ (Brazil). Inst. de Fisica; Coimbra, M.M. [Universidade Estadual de Londrina, PR (Brazil). Dept. de Fisica; Elmore, D. [Purdue Univ., IN (United States). Purdue Rare Isotopes Measurement Lab.

    2003-06-01

    This paper discusses the chronology of prehistoric settlements of the central-south Brazilian coast. A charcoal sample from a coastal shell mound of Rio de Janeiro State was dated by {sup 14} C-AMS to 7, 860+- 80 years B P as part of an interdisciplinary project between physicists and archaeologists. This is an unexpected result that reinforces two similar previous early dates for the same region, which were questioned by Brazilian archaeologists because they implied in pulling back by some two thousand years the antiquity consensually accepted for the settlement of that region. (author)

  16. Radiocarbon calibration - past, present and future

    NARCIS (Netherlands)

    van der Plicht, J

    2004-01-01

    Calibration of the Radiocarbon timescale is traditionally based on tree-rings dated by dendrochronology. At present, the tree-ring curve dates back to about 9900 BC. Beyond this limit, marine datasets extend the present calibration curve INTCAL98 to about 15600 years ago. Since 1998, a wealth of AMS

  17. Blank corrections for ramped pyrolysis radiocarbon dating of sedimentary and soil organic carbon.

    Science.gov (United States)

    Fernandez, Alvaro; Santos, Guaciara M; Williams, Elizabeth K; Pendergraft, Matthew A; Vetter, Lael; Rosenheim, Brad E

    2014-12-16

    Ramped pyrolysis (RP) targets distinct components of soil and sedimentary organic carbon based on their thermochemical stabilities and allows the determination of the full spectrum of radiocarbon ((14)C) ages present in a soil or sediment sample. Extending the method into realms where more precise ages are needed or where smaller samples need to be measured involves better understanding of the blank contamination associated with the method. Here, we use a compiled data set of RP measurements of samples of known age to evaluate the mass of the carbon blank and its associated (14)C signature, and to assess the performance of the RP system. We estimate blank contamination during RP using two methods, the modern-dead and the isotope dilution method. Our results indicate that during one complete RP run samples are contaminated by 8.8 ± 4.4 μg (time-dependent) of modern carbon (MC, fM ∼ 1) and 4.1 ± 5.5 μg (time-independent) of dead carbon (DC, fM ∼ 0). We find that the modern-dead method provides more accurate estimates of uncertainties in blank contamination; therefore, the isotope dilution method should be used with caution when the variability of the blank is high. Additionally, we show that RP can routinely produce accurate (14)C dates with precisions ∼100 (14)C years for materials deposited in the last 10,000 years and ∼300 (14)C years for carbon with (14)C ages of up to 20,000 years.

  18. Insights into Holocene megafauna survival and extinction in southeastern Brazil from new AMS 14C dates

    Science.gov (United States)

    Hubbe, Alex; Hubbe, Mark; Karmann, Ivo; Cruz, Francisco W.; Neves, Walter A.

    2013-03-01

    The extinction of late Quaternary megafauna in South America has been extensively debated in past decades. The majority of the hypotheses explaining this phenomenon argue that the extinction was the result of human activities, environmental changes, or even synergism between the two. Although still limited, a good chronological framework is imperative to discuss the plausibility of the available hypotheses. Here we present six new direct AMS 14C radiocarbon dates from the state of São Paulo (Brazil) to further characterize the chronological distribution of extinct fauna in this part of South America. The new dates make evident that ground sloths, toxodonts, and saber-toothed cats lived in the region around the Pleistocene/Holocene transition, and, in agreement with previous studies, also suggest an early Holocene survival for the ground sloth Catonyx cuvieri. Taken together with local paleoclimatic and archaeological data, the new dates do not support hunting or indirect human activities as a major cause for megafauna extinction. Although more data are required, parsimony suggests that climatic changes played a major role in this extinction event.

  19. Thermal history of the Acoculco geothermal system, eastern Mexico: Insights from numerical modeling and radiocarbon dating

    Science.gov (United States)

    Canet, Carles; Trillaud, Frederic; Prol-Ledesma, Rosa María; González-Hernández, Galia; Peláez, Berenice; Hernández-Cruz, Berenice; Sánchez-Córdova, María M.

    2015-10-01

    Acoculco is a geothermal prospective area hosted by a volcanic caldera complex in the eastern Trans-Mexican Volcanic Belt. Surface manifestations are scarce and consist of gas discharges (CO2-rich) and acid-sulfate springs of low temperature, whereas hydrothermal explosive activity is profusely manifested by meter-scale craters and mounds of hydrothermal debris and breccias. Silicic alteration extends for several square kilometers around the zone with gas manifestations and explosive features, affecting surficial volcanic rocks, primarily tuffs and breccias. In the subsurface, an argillic alteration zone (ammonium illite) extends down to a depth of ∼ 600 m, and underneath it a propylitic zone (epidote-calcite-chlorite) occurs down to ∼ 1000 m. Thermal logs from an exploratory borehole (EAC-1, drilled in 1995 down to 1810 m) showed a conductive heat transfer regime under high geothermal gradient (∼ 140 °C/1000 m). In contrast, the thermal profile established from temperatures of homogenization of fluid inclusions-measured on core samples from the same drill hole-suggests that convection occurred in the past through the upper ~ 1400 m of the geothermal system. A drop in permeability due to the precipitation of alteration minerals would have triggered the cessation of the convective heat transfer regime to give place to a conductive one. With the purpose of determining when the transition of heat transfer regime occurred, we developed a 1D model that simulates the time-depth distribution of temperature. According to our numerical simulations, this transition happened ca. 7000 years ago; this date is very recent compared to the lifespan of the geothermal system. In addition, radiocarbon chronology indicates that the hydrothermal explosive activity postdates the end of the convective heat transfer regime, having dated at least three explosive events, at 4867-5295, 1049-1417 and 543-709 y cal. BP. Therefore, hydrothermal explosions arise from the self-sealing of

  20. Radiocarbon dating of the human eye lens crystallines reveal proteins without carbon turnover throughout life.

    Directory of Open Access Journals (Sweden)

    Niels Lynnerup

    Full Text Available BACKGROUND: Lens crystallines are special proteins in the eye lens. Because the epithelial basement membrane (lens capsule completely encloses the lens, desquamation of aging cells is impossible, and due to the complete absence of blood vessels or transport of metabolites in this area, there is no subsequent remodelling of these fibers, nor removal of degraded lens fibers. Human tissue ultimately derives its (14C content from the atmospheric carbon dioxide. The (14C content of the lens proteins thus reflects the atmospheric content of (14C when the lens crystallines were formed. Precise radiocarbon dating is made possible by comparing the (14C content of the lens crystallines to the so-called bomb pulse, i.e. a plot of the atmospheric (14C content since the Second World War, when there was a significant increase due to nuclear-bomb testing. Since the change in concentration is significant even on a yearly basis this allows very accurate dating. METHODOLOGY/PRINCIPAL FINDINGS: Our results allow us to conclude that the crystalline formation in the lens nucleus almost entirely takes place around the time of birth, with a very small, and decreasing, continuous formation throughout life. The close relationship may be further expressed as a mathematical model, which takes into account the timing of the crystalline formation. CONCLUSIONS/SIGNIFICANCE: Such a life-long permanence of human tissue has hitherto only been described for dental enamel. In confront to dental enamel it must be held in mind that the eye lens is a soft structure, subjected to almost continuous deformation, due to lens accommodation, yet its most important constituent, the lens crystalline, is never subject to turnover or remodelling once formed. The determination of the (14C content of various tissues may be used to assess turnover rates and degree of substitution (for example for brain cell DNA. Potential targets may be nervous tissues in terms of senile or pre

  1. Molecular Radiocarbon Dating of Tropical Lake Sediments: Insights into the Chronology of Leaf Wax Stable Isotope Records

    Science.gov (United States)

    Douglas, P. M.; Pagani, M.; Eglinton, T. I.; Brenner, M.; Curtis, J. H.; Hodell, D. A.

    2010-12-01

    Leaf wax δD and δ13C measurements in marine and lacustrine sediment cores are promising proxies for past climatic and environmental change. However, a number of studies of marine sediments indicate centennial to millennial scale offsets between the radiocarbon ages of leaf waxes and the age of surrounding sediments due to long-term storage of these lipids in soils. These offsets present a complication for the interpretation of leaf wax stable isotope records that has not been thoroughly addressed. We present leaf wax δD, δ13C and Δ14C values for a sediment core from Lake Chichancanab in southeastern Mexico. This lake was previously studied using mineralogical (gypsum) and carbonate isotopic (δ18O) climate proxies, which indicated a sequence of severe droughts from 750 to 1000 AD, coincident with the collapse of the Classic Maya civilization. A suite of leaf wax δD values was plotted against the original sediment core chronology, which was developed using radiocarbon dates on terrestrial macrofossils. The leaf wax results also indicated major hydrological variability over the past 3000 years, but were not temporally coherent with the other climate proxy records. Leaf wax radiocarbon ages are 400 to 1200 years older than terrestrial macrofossil radiocarbon ages from the same depths, suggesting that leaf waxes are retained in the watershed for extended periods prior to deposition in the lake. We fit a 2nd-order polynomial equation to the depth profile of leaf wax radiocarbon ages (r2 =0.99) and refit the leaf wax δD profile to this “leaf wax age model”. This approach yielded much greater coherence with mineralogical and carbonate isotopic proxy records, including evidence for a period of severe drought (35‰ D-enrichment) from 750 to 1000 A.D. Our results indicate that long-term storage of leaf waxes in drainage basin soils can lead to temporal inaccuracies in leaf wax stable isotope records. These inaccuracies, however, can be corrected using a

  2. Radiocarbon calibration - past, present and future

    Energy Technology Data Exchange (ETDEWEB)

    Plicht, J. van der E-mail: plicht@phys.rug.nl

    2004-08-01

    Calibration of the Radiocarbon timescale is traditionally based on tree-rings dated by dendrochronology. At present, the tree-ring curve dates back to about 9900 BC. Beyond this limit, marine datasets extend the present calibration curve INTCAL98 to about 15 600 years ago. Since 1998, a wealth of AMS measurements became available, covering the complete {sup 14}C dating range. No calibration curve can presently be recommended for the older part of the dating range until discrepancies are resolved.

  3. Hard-water dynamics and their reservoir effects on radiocarbon dating of Lake Heihai sediments (NE Tibetan Plateau, Qinghai, China)

    Science.gov (United States)

    Lockot, Gregori; Hartmann, Kai; Wünnemann, Bernd; Ramisch, Arne; Diekmann, Bernhard

    2014-05-01

    Age determination of lake sediments with radiocarbon dating can always entail a perturbation with hard water. Atmospheric carbon (expressing the "real" ages) can be mixed with older carbon from allochthonous input (e.g. marl or limestone), causing an overestimation of 14C ages. The usual approach to eliminate this effect is to date living plants or shells to determine the modern offset in age. Subsequently, this offset is subtracted from 14C ages of a sediment core to attain hard water corrected ages. However, this approach assumes a constant hard water effect over the entire period under consideration, which generally is unlikely. Here we present a highly variable hard water effect through time determined from a combined chronology of two long sediment cores from Lake Heihai (NE Tibetan Plateau). The chronology is based on 20 14C AMS dates of Potamogeton spec. Based on the relation between 14C ages and the input of allochthonous carbonates as well as calculated sedimentation rates, we developed an age-depth-model that estimates the actual ages of the sediments and allows the quantification of hard water effect through time. As a result this model suggests a fluctuating hard water effect varying between 102 to 103 ka. Ages in the lower 3 meter of the core, which corresponds to late glacial times, strongly correlate with the input of dolomite (CaMg(CO3)2). The correlation suggests a strong linkage between the allochthonous input of old carbon and the variations in dating results. In this section, the estimated hard water effect shows its highest values. Results of XRD, grain size and pollen data confirm a shallow lake with high rates of detrital input. The Late Glacial - Holocene transition to warmer and wetter conditions is marked by prominent changes in the mineralogy of lacustrine carbonates and the composition of pollen taxa. During this time the lake constantly rose and increasingly buffered the influence of allochthonous carbonates. The episode is

  4. A simple radiocarbon dating method for determining the age and growth rate of deep-sea sponges

    Energy Technology Data Exchange (ETDEWEB)

    Fallon, S.J., E-mail: stewart.fallon@anu.edu.a [Research School of Earth Sciences, Australian National University (Australia); James, K.; Norman, R. [Research School of Earth Sciences, Australian National University (Australia); Kelly, M. [National Centre for Aquatic Biodiversity and Biosecurity, National Institute of Water and Atmospheric Research (NIWA) Ltd., Auckland (New Zealand); Ellwood, M.J. [Research School of Earth Sciences, Australian National University (Australia)

    2010-04-15

    The ability to reliably age siliceous sponges is explored using radiocarbon dating of several hexactinellid sponge specimens including Rossella racovitzaeracovitzae Topsent, 1901 (C. Hexactinellida: O. Lyssacinosida: F. Rossellidae), collected from the Ross Sea, Antarctica. The optimal pretreatment was found to consist of both sequential acid digestion and pre-roasting at temperatures >400 deg. C. Subsequent combustion at 900 deg. C liberated the proteinaceous material within the spicule matrix and once the reservoir age of the surrounding water was accounted for, a linear extension rate was calculated to be around 2.9 mm yr{sup -1}, aging the sponge at approx440 years old.

  5. A radiocarbon-dated cave sequence and the Pleistocene/Holocene transition in Hungary

    Science.gov (United States)

    Sümegi, Pál; Náfrádi, Katalin

    2015-11-01

    The Petény Cave located on the Hungarian Highlands yielded one of the most well-documented vertebrate fauna of the Late Pleistocene and Holocene in Hungary. In addition to the vertebrate remains, considerable numbers of mollusc shells and charcoals were retrieved from the profile of the rock shelter. Furthermore, a pollen sequence close to the cavewas also evaluated in order to reconstruct the flora of the region. A new radiocarbon analysis of samples from the Petény Cave was used to correlate data of different methods and to correct the earlier outcomes. The cave sequence exposes layers from 15.180 cal BP to 483 cal BP. Nevertheless, based on our new radiocarbon data, the sequence is incomplete and layers corresponding to the Pleistocene/Holocene boundary are missing from the profile. The results of our radiocarbon analysis clearly support considerable amounts of thermo-mesophylous gastropod species appearing as early as 15.180 cal BP. The appearance of deciduous woodlands in the Carpathian Basin along with the concomitant mollusc elements is much earlier than previously assumed, supporting the presence of temperate woodland refugia in the study area.

  6. Fully automated radiocarbon AMS measurements with elemental analyser and gas ion source

    Energy Technology Data Exchange (ETDEWEB)

    Ruff, Matthias; Gaeggeler, Heinz [University of Berne (Switzerland)]|[Paul Scherrer Institute (Switzerland); Suter, Martin [ETH Zurich (Switzerland)]|[PSI/ETH Zurich (Switzerland); Synal, Hans-Arno [PSI/ETH Zurich (Switzerland); Szidat, Soenke [University of Berne (Switzerland); Lukas, Wacker [ETH Zurich (Switzerland)

    2008-07-01

    The MIACADAS gas ion source in Zurich for measuring radiocarbon in small samples in the range of 2-50 ug carbon is now routinely running semi-automated for more than one and a half years. So far the carbon dioxide to be measured is supplied in glass ampoules and released in an ampoule cracker. The gas is flushed into a syringe with helium and transported onto the surface of a titanium gas target in the Cs sputter ion source. Thereby, the syringe acts as an adjustable tool according to the sample size and can also be moved by a stepping motor to keep a constant flow into the source. For full automation of this system an elemental analyser has been connected for combustion of the sample and separation of the combustion gases. The isolated carbon dioxide leaves the elemental analyser in a high helium stream of about 80 ml/min and has to be first concentrated on a small trap before feeding it into the syringe. Some technical solutions and first results of this automated online system are discussed.

  7. Spatial gradients in Clovis-age radiocarbon dates across North America suggest rapid colonization from the north.

    Science.gov (United States)

    Hamilton, Marcus J; Buchanan, Briggs

    2007-10-02

    A key issue in the debate over the initial colonization of North America is whether there are spatial gradients in the distribution of the Clovis-age occupations across the continent. Such gradients would help indicate the timing, speed, and direction of the colonization process. In their recent reanalysis of Clovis-age radiocarbon dates, Waters and Stafford [Waters MR, Stafford TW, Jr (2007) Science 315:1122-1126] report that they find no spatial patterning. Furthermore, they suggest that the brevity of the Clovis time period indicates that the Clovis culture represents the diffusion of a technology across a preexisting pre-Clovis population rather than a population expansion. In this article, we focus on two questions. First, we ask whether there is spatial patterning to the timing of Clovis-age occupations and, second, whether the observed speed of colonization is consistent with demic processes. With time-delayed wave-of-advance models, we use the radiocarbon record to test several alternative colonization hypotheses. We find clear spatial gradients in the distribution of these dates across North America, which indicate a rapid wave of advance originating from the north. We show that the high velocity of this wave can be accounted for by a combination of demographic processes, habitat preferences, and mobility biases across complex landscapes. Our results suggest that the Clovis-age archaeological record represents a rapid demic colonization event originating from the north.

  8. High-precision radiocarbon dating of political collapse and dynastic origins at the Maya site of Ceibal, Guatemala.

    Science.gov (United States)

    Inomata, Takeshi; Triadan, Daniela; MacLellan, Jessica; Burham, Melissa; Aoyama, Kazuo; Palomo, Juan Manuel; Yonenobu, Hitoshi; Pinzón, Flory; Nasu, Hiroo

    2017-02-07

    The lowland Maya site of Ceibal, Guatemala, had a long history of occupation, spanning from the Middle Preclassic Period through the Terminal Classic (1000 BC to AD 950). The Ceibal-Petexbatun Archaeological Project has been conducting archaeological investigations at this site since 2005 and has obtained 154 radiocarbon dates, which represent the largest collection of radiocarbon assays from a single Maya site. The Bayesian analysis of these dates, combined with a detailed study of ceramics, allowed us to develop a high-precision chronology for Ceibal. Through this chronology, we traced the trajectories of the Preclassic collapse around AD 150-300 and the Classic collapse around AD 800-950, revealing similar patterns in the two cases. Social instability started with the intensification of warfare around 75 BC and AD 735, respectively, followed by the fall of multiple centers across the Maya lowlands around AD 150 and 810. The population of Ceibal persisted for some time in both cases, but the center eventually experienced major decline around AD 300 and 900. Despite these similarities in their diachronic trajectories, the outcomes of these collapses were different, with the former associated with the development of dynasties centered on divine rulership and the latter leading to their downfalls. The Ceibal dynasty emerged during the period of low population after the Preclassic collapse, suggesting that this dynasty was placed under the influence from, or by the direct intervention of, an external power.

  9. Development of a method for fast and automatic radiocarbon measurement of aerosol samples by online coupling of an elemental analyzer with a MICADAS AMS

    Energy Technology Data Exchange (ETDEWEB)

    Salazar, G., E-mail: gary.salazar@dcb.unibe.ch [Department of Chemistry and Biochemistry & Oeschger Centre for Climate Change Research, University of Bern, 3012 Bern (Switzerland); Zhang, Y.L.; Agrios, K. [Department of Chemistry and Biochemistry & Oeschger Centre for Climate Change Research, University of Bern, 3012 Bern (Switzerland); Paul Scherrer Institut (PSI), 5232 Villigen (Switzerland); Szidat, S. [Department of Chemistry and Biochemistry & Oeschger Centre for Climate Change Research, University of Bern, 3012 Bern (Switzerland)

    2015-10-15

    A fast and automatic method for radiocarbon analysis of aerosol samples is presented. This type of analysis requires high number of sample measurements of low carbon masses, but accepts precisions lower than for carbon dating analysis. The method is based on online Trapping CO{sub 2} and coupling an elemental analyzer with a MICADAS AMS by means of a gas interface. It gives similar results to a previously validated reference method for the same set of samples. This method is fast and automatic and typically provides uncertainties of 1.5–5% for representative aerosol samples. It proves to be robust and reliable and allows for overnight and unattended measurements. A constant and cross contamination correction is included, which indicates a constant contamination of 1.4 ± 0.2 μg C with 70 ± 7 pMC and a cross contamination of (0.2 ± 0.1)% from the previous sample. A Real-time online coupling version of the method was also investigated. It shows promising results for standard materials with slightly higher uncertainties than the Trapping online approach.

  10. Holocene radiocarbon-dated sites in northeastern Siberia: issues of temporal frequency, reservoir age, and human-nature interaction.

    Science.gov (United States)

    Kuzmin, Yaroslav V

    2010-01-01

    The existing corpus of data on radiocarbon dates for Holocene sites in Northeastern Siberia was used as proxy to reconstruct the chronology of human occupation of the region. The problem of reservoir age correction in the Bering Sea region complicated this task and this issue needs to be solved in order to obtain more reliable age determinations for coastal archaeological sites. Using a chronology built after excluding the questionable dates from the database, the major patterns of human population dynamics and their possible correlation with climatic fluctuations were examined. No direct relationship appears to exist between these two processes. Additional archaeological and paleo environmental work needs to be carried out in this region of the North.

  11. Environmental changes in the western Amazonia: morphological framework, geochemistry, palynology and radiocarbon dating data

    Energy Technology Data Exchange (ETDEWEB)

    Horbe, Adriana M.C., E-mail: ahorbe@ufam.edu.b [Universidade Federal do Amazonas (UFAM), Manaus, AM (Brazil). Dept. de Geociencias; Behling, Hermann [Georg August Universitaet Goettingen (Germany). Albrecht von Haller Institut fuer Pflanzenwissenschaften. Abteilung fuer Palynologie und Klimadynamik; Nogueira, Afonso C.R. [Universidade Federal do Para (UFPA), Belem, PA (Brazil). Inst. de Geociencias; Mapes, Russell [University of North Carolina, Chapel Hill, NC (United States). Dept. of Geological Science

    2011-09-15

    The sediments from the Coari lake, a 'terra firme' lake sculpted into Plio-Pleistocene deposits, and the Acara lake, a flooding-type lake developed on Quaternary sediments in the flood plain of the mid-Solimoes river, in the western Amazonia, Brazil, were studied to investigate the environmental condition of their developing. This study includes mineral composition, geochemistry, Pb isotope, palynology, radiocarbon-age and morphological framework of the lakes obtained from SRTM satellite images. The geological and the environmental conditions in the two lakes are highly variable and suggest that their evolution reflect autogenic processes under humid rain forest condition. Although kaolinite, quartz, muscovite, illite, and smectite are the main minerals in both lakes, the geochemistry indicates distinct source, the Acara lake sediments have higher concentrations of Al{sub 2}O{sub 3}, Fe{sub 2}O{sub 3}, FeO, CaO, K{sub 2}O, MgO, Na{sub 2}O, P{sub 2}O{sub 5}, Ba, V, Cu, Ni, Zn, Pb, Sr, Li, Y and La and have more radiogenic Pb than the Coari lake sediments. The radiocarbon ages suggest that at 10160 yr BP the Coari lake started to be developed due to avulsion of the Solimoes river, and the Acara lake was formed by the meander abandonment of Solimoes river retaining its grass dominated shore at ca. 3710 yr BP. (author)

  12. Peeking Under the Ice… Literally: Records of Arctic Climate Change from Radiocarbon Dating Moss Emerging from Beneath Retreating Glaciers

    Science.gov (United States)

    Briner, J. P.; Schweinsberg, A.; Miller, G. H.; Lifton, N. A.; Beel, C. R.; Bennike, O.

    2014-12-01

    Dramatic changes are taking place throughout the Arctic. Many glaciers have already melted away completely, and most others are well on their way as rising snowline elevations promise continued glacier retreat. Emerging from beneath retreating glacier margins is a landscape rich in information about past climate and glacier changes. Within newly exposed bedrock is an inventory of cosmogenic nuclides that archive past ice cover timing and duration. Lake basins re-appearing due to retreating ice preserve sediment archives that tell of cooling climate and advancing ice. And ancient surfaces vegetated with tundra communities that have long been entombed beneath frozen-bedded ice caps are now being revealed for the first time in millennia. This presentation will focus on the climate and glacier record derived from radiocarbon dating of in situ moss recently exhumed from retreating local ice cap margins on western Greenland. Dozens of radiocarbon ages from moss group into several distinct modes, which are interpreted as discrete times of persistent summer cooling and resultant glacier expansion. The data reveal a pattern of glacier expansion beginning ~5000 years ago, followed by periods of glacier growth around 3500 and 1500 years ago. Because these times of glacier expansion are recorded at many sites in western Greenland and elsewhere in the Arctic, they are interpreted as times of step-wise summer cooling events during the Holocene. These non-linear climate changes may be a result of feedbacks that amplify linear insolation forcing of Holocene climate. In addition to these insights into the Arctic climate system, the antiquity of many radiocarbon ages of ice-killed moss indicate that many arctic surfaces are being re-exposed for the first time in millennia due to retreating ice, emphasizing the unprecedented nature of current summer warming.

  13. Preparing and measuring ultra-small radiocarbon samples with the ARTEMIS AMS facility in Saclay, France

    Energy Technology Data Exchange (ETDEWEB)

    Delque-Kolic, E., E-mail: emmanuelle.delque-kolic@cea.fr [LMC14, CEA Saclay, Batiment 450 Porte 4E, 91191 Gif sur Yvette (France); Comby-Zerbino, C.; Ferkane, S.; Moreau, C.; Dumoulin, J.P.; Caffy, I.; Souprayen, C.; Quiles, A.; Bavay, D.; Hain, S.; Setti, V. [LMC14, CEA Saclay, Batiment 450 Porte 4E, 91191 Gif sur Yvette (France)

    2013-01-15

    The ARTEMIS facility in Saclay France measures, on average, 4500 samples a year for French organizations working in an array of fields, including environmental sciences, archeology and hydrology. In response to an increasing demand for the isolation of specific soil compounds and organic water fractions, we were motivated to evaluate our ability to reduce microgram samples using our standard graphitization lines and to measure the graphite thus obtained with our 3MV NEC Pelletron AMS. Our reduction facility consists of two fully automated graphitization lines. Each line has 12 reduction reactors with a reduction volume of 18 ml for the first line and 12 ml for the second. Under routine conditions, we determined that we could reduce the samples down to 10 {mu}g of carbon, even if the graphitization yield is consequently affected by the lower sample mass. Our results when testing different Fe/C ratios suggest that an amount of 1.5 mg of Fe powder was ideal (instead of lower amounts of catalyst) to prevent the sample from deteriorating too quickly under the Cs+ beam, and to facilitate pressing procedures. Several sets of microsamples produced from HOxI standard, international references and backgrounds were measured. When measuring {sup 14}C-free wood charcoal and HOxI samples we determined that our modern and dead blanks, due to the various preparation steps, were of 1.1 {+-} 0.8 and 0.2 {+-} 0.1 {mu}g, respectively. The results presented here were obtained for IAEA-C1, {sup 14}C-free wood, IAEA-C6, IAEA-C2 and FIRI C.

  14. Age validation of canary rockfish (Sebastes pinniger) using two independent otolith techniques: lead-radium and bomb radiocarbon dating.

    Energy Technology Data Exchange (ETDEWEB)

    Andrews, A H; Kerr, L A; Cailliet, G M; Brown, T A; Lundstrom, C C; Stanley, R D

    2007-11-04

    Canary rockfish (Sebastes pinniger) have long been an important part of recreational and commercial rockfish fishing from southeast Alaska to southern California, but localized stock abundances have declined considerably. Based on age estimates from otoliths and other structures, lifespan estimates vary from about 20 years to over 80 years. For the purpose of monitoring stocks, age composition is routinely estimated by counting growth zones in otoliths; however, age estimation procedures and lifespan estimates remain largely unvalidated. Typical age validation techniques have limited application for canary rockfish because they are deep dwelling and may be long lived. In this study, the unaged otolith of the pair from fish aged at the Department of Fisheries and Oceans Canada was used in one of two age validation techniques: (1) lead-radium dating and (2) bomb radiocarbon ({sup 14}C) dating. Age estimate accuracy and the validity of age estimation procedures were validated based on the results from each technique. Lead-radium dating proved successful in determining a minimum estimate of lifespan was 53 years and provided support for age estimation procedures up to about 50-60 years. These findings were further supported by {Delta}{sup 14}C data, which indicated a minimum estimate of lifespan was 44 {+-} 3 years. Both techniques validate, to differing degrees, age estimation procedures and provide support for inferring that canary rockfish can live more than 80 years.

  15. Methodological aspects about the use of the radicarbon dating in historical time sites

    Directory of Open Access Journals (Sweden)

    Lubritto, Carmine

    2009-01-01

    Full Text Available In this paper basic concepts concerning radiocarbon dating and Accelerator Mass Spectrometry (AMS technique, and specifically the Centre for Isotopic Research on Cultural and Environmental heritage (CIRCE Laboratory AMS facility, will be given. Problem of contaminations in radiocarbon AMS measurements will be introduced, and the sample preparation laboratory and the graphitisation lines that are used at the CIRCE Laboratory will be presented. Moreover problems of sampling and interpretation of the archaeological radiocarbon dates will be treated in consideration of the nature of interdisciplinary research and of the impact of radiocarbon dating on archaeology.

  16. THE EFFECTS OF POSSIBLE CONTAMINATION ON THE RADIOCARBON DATING OF THE DEAD SEA SCROLLS II : EMPIRICAL METHODS TO REMOVE CASTOR OIL AND SUGGESTIONS FOR REDATING

    NARCIS (Netherlands)

    Rasmussen, Kaare Lund; van der Plicht, Johannes; Doudna, Gregory; Nielsen, Frederik; Hojrup, Peter; Stenby, Erling Halfdan; Pedersen, Carl Th; Højrup, Peter

    2009-01-01

    While kept at the Rockefeller Museum in East Jerusalem, many Dead Sea Scroll fragments were exposed to castor oil by the original team of editors in the course of cleaning the parchments. Castor oil must be regarded as a serious contaminant in relation to radiocarbon dating. If modern castor oil is

  17. On the Reliability of the Radiocarbon Dating of Archaeological Series Samples%关于考古系列样品碳十四测年方法的可靠性问题

    Institute of Scientific and Technical Information of China (English)

    仇士华; 蔡莲珍

    2001-01-01

    The method of radiocarbon dating of series samples unearthed from archaeological sites is briefly explained on both theoretical and practical levels. Some questions raised by archaeologists are answered. It is emphasized that the method of radiocarbon dating of series samples should be widely used especially when chronological problems in ancient civilization studies need to be solved.

  18. Radiocarbon Dates Link Marine Incursion and Neoglacial Ice Terminus Advance With Tlingit Ethnohistory and Archeology in Lower Glacier Bay

    Science.gov (United States)

    Connor, C. L.; Monteith, D.; Howell, W.; Strevelar, G.; Leirer, M.

    2004-12-01

    Radiocarbon dates from wood, organic sediments, and marine shells were collected from eroded beach terraces and upper beach sediments in the Beardslee Islands and Berg Bay in Glacier Bay National Park, Alaska. These provide a timetable for the the outwash plain construction and final advance of the Late Neoglacial glacier front over this outwash plain into lower Glacier Bay. On Kidney Island in the central Beardslee Islands, marine sediments containing Macoma baltica shells were deposited 4310 +/- 40 years BP. Outwash from advancing up-bay glaciers, buried these sediments and created terrestrial substrates upon which forests existed by 1630 +/- 60 BP and 1300 +/- 50 yrs BP. Final ice advance over this forested outwash plain occurred after 430 +/- 60 BP (1430 to 1510 AD) on Kidney Island. This ice arrived at the southern edge of Lester Island in Bartlett Cove after 370 +/- 50 BP (1440 to 1520 AD); preceding the arrival of George Vancouver in 1794 AD. In nearby Icy Straits, archeological investigations have yielded some of the oldest dates of human occupation in the region at 10,180 +/- 800 uncorrected years BP (Ackerman, 1968). In Glacier Bay's ethno-historically rich areas of Bartlett Cove, the Beardslee Islands and Berg Bay the Huna people have names for places and narratives that describe late Neoglacial landscapes. S'é Shuyee is the "area at the end of the glacial mud", L'awsha Shakee Aan "town on top of the glacial sand dunes". There are accounts of villages overrun by surging glaciers, and a name for the bay Sit' eeti Geeyi that translates as "bay in place of the glacier". These dates provide linkage between the geological, archeological, and ethnohistorical evidence that chronicles the history of the Huna people in this dynamic glacier marine environment.

  19. Investigations on alluvial deposits through borehole stratigraphy, radiocarbon dating and passive seismic technique (Carnic Alps, NE Italy)

    Science.gov (United States)

    Viero, Alessia; Marchi, Lorenzo; Cavalli, Marco; Crema, Stefano; Fontana, Alessandro; Mozzi, Paolo; Venturini, Corrado

    2016-04-01

    Alluvial sediment investigations provide fundamental tools to infer the processes that control geomorphological evolution of mountain environments. By analyzing sediment stratigraphy in depth, it is possible to retrieve the source, the geology, the time of deposition, the relative distance travelled by material as well as to distinguish among different type of transport (i.e., gravitational, fluvial or glacial). In this work, we present a combination of log stratigraphy, radiocarbon dating and geophysical surveys carried out on the valley floor of the But River (Carnic Alps, North East Italy). The But River basin drains an area of 326 km2 with a range in elevation from 2769 to 323 m a.s.l.; the bedrock mainly consists of carbonates and quartz arenites with minor inclusions of effusive rocks. After Pleistocene the gravitational deposits from mountain slopes have impounded the But River several times. In particular, we analyzed a sector of the upper portion of the But valley close to the confluence of the Moscardo Torrent, frequently affected by debris flows. A borehole was drilled in the But River floodplain, at the intersection with the Moscardo Torrent alluvial fan, down to a depth of 80 m. The analysis of the core samples allowed discerning three sedimentary levels rich in clay and organic materials, which testify the presence of small dam lakes, originated from the Moscardo debris-flow deposits. Three samples of wood and plant debris were collected from 13, 14 and 23 m of depth, respectively. They were analyzed through radiocarbon dating in order to determine the age of the lakes and, thus, to infer the activity of the debris flows building the Moscardo cone. The calibrated ages of the 3 samples are close to the younger limit of the radiocarbon method indicating a fast aggradation of the valley floor, starting from a period ranging between 1450 - 1632 AD. Historical maps and documents confirm the presence of the lakes until 19th century and they permit to assess

  20. Coastal rainforest boundary dynamics during the late Holocene in monsoonal Australia: evidence from radiocarbon dates of abandoned nests of Orange-footed Scrubfowl

    Energy Technology Data Exchange (ETDEWEB)

    Bowman, D.M.J.S.; Panton, W.J. [Parks and Wildlife Commission of the Northern Territory, Darwin, NT (Australia); Head, J. [Australian National Univ, Canberra, ACT (Australia). Quaternary Dating Research Centre

    1997-12-31

    The late Holocene history of monsoon rainforest retreat was explored by radiocarbon dating abandoned Orange-footed Scrubfowl (Megapodius reinwardt Gaimard) nests in coastal savannas in the Northern Territory of Australia. Previous work has demonstrated that in savanna environments this rainforest bird can not build nor maintain the large heaps of soil and leaf litter that it uses for nests. Excavations of two earthen mounds in a savanna habitat verified that they were abandoned Scrubfowl nests, and not Aboriginal middens, given their lack of stratigraphy, non-sequential dating of charcoal in a vertical profile, and absence of archaeological material. Radiocarbon dates of material taken from the surface of abandoned nests were determined for three sites on the coast of the Northern Territory. These analyses revealed that for all three sites, rainforests have contracted within the last 1800 years BP. On Elcho Island an abandoned nest was found to contain the land snail Xanthomelon spheroidea Le Guillou (known to prefer rainforest habitat) with a modern radiocarbon age, suggesting recent contraction of rainforest. The results of this study further weaken the theory that Aboriginal burning was a major cause of rain forest fragmentation in the monsoon tropics, and possibly elsewhere in Australia.

  1. A review of single-sample-based models and other approaches for radiocarbon dating of dissolved inorganic carbon in groundwater

    Science.gov (United States)

    Han, L. F; Plummer, Niel

    2016-01-01

    underlying assumptions on which the various models and approaches are based can result in a wide range of estimates of 14C0 and limit the usefulness of radiocarbon as a dating tool for groundwater. In each of the three generalized approaches (single-sample-based models, statistical approach, and geochemical mass-balance approach), successful application depends on scrutiny of the isotopic (14C and 13C) and chemical data to conceptualize the reactions and processes that affect the 14C content of DIC in aquifers. The recently developed graphical analysis method is shown to aid in determining which approach is most appropriate for the isotopic and chemical data from a groundwater system.

  2. Fine-tuning of age integrating magnetostratigraphy, radiocarbon dating, and carbonate cyclicity: Example of lacustrine sediments from Heqing basin (Yunnan, China) covering the past 1 Myr

    Science.gov (United States)

    Hu, Shouyun; Goddu, Srinivasa Rao; Appel, Erwin; Verosub, Ken

    2007-05-01

    High-resolution magnetostratigraphy, wavelength spectra of carbonate cyclicities, and AMS radiocarbon dating are integrated to establish an optimum age model for a 168 m long drill core of lacustrine sediments from Heqing basin, Yunnan Province, southwestern China. A 14C age of 51.62 +2.42/-1.85 kyr BP is obtained at a depth of 7.3 m. Remanent magnetization is carried by maghemite and partly in addition by magnetite, both showing the same direction. The polarity sequence clearly reveals the Brunhes/Matuyama (B/M) boundary at 141.5 m. Blake Event is found between 16.3 and 17.5 m, and the upper boundary of Jaramillo is indicated at 167.0 m. Carbonate content and magnetic susceptibility were used for spectral analysis. Fourier analysis was done on the depth section for sliding windows with different window lengths. The spectra within the range of window centers (30-140 m) show a dominant long wavelength, which changes from about 18.5 m in the lower part (>65 m depth) to about 14.5 m in the upper part (B/M boundary and Blake Event match very well with this model, but the age of Jaramillo is strongly underestimated. Fourier spectra of sliding windows slightly indicate a drop of the sedimentation rate at the lowermost part of the core. An optimum age model is calculated by cubic spline interpolation using tie points from 14C dating, magnetostratigraphy ('true' ages of Blake Event, B/M boundary, and Jaramillo), and wavelengths of carbonate (change in sedimentation rate at 65 m). Alternative depth-to-age transfer functions were tested, i.e. a wavelength age model (using sedimentation rates with 14C as a tie point), a cyclostratigraphic model (using bandpass-filtered carbonate data corresponding to 95 kyr eccentricity cycles) and correlation of carbonate variations to the marine oxygen isotope curve. However, none of the approaches lead to a convincing Milankovitch spectrum of whole-core carbonate data. The Fourier spectra of whole-core carbonate and susceptibility time

  3. Radiocarbon dates of the Iron Age hillfort of O Achadizo (Boiro, A Coruña, NW Iberia: an approach to the dating of marine shells

    Directory of Open Access Journals (Sweden)

    Rubinos Pérez, Antonio

    1999-06-01

    Full Text Available The excavation of the hillfort of O Achadizo has brought to light several domestic structures intermingled with rubish heaps, belonging to the Iron Age Castro culture of NW Iberia. The abundant organic remains have constituted the basis for a systematic programme of radiocarbon dating of the different stratigraphic levels, which shows that the main occupation of the site took place between the VI and the II centuries cal. BC. Moreover, we have checked the 14C dates obtained from terrestrial samples (bones and charcoal against those made on marine shells coming from the same strata. As a result, we have found that the latter have an apparent age of 316±I9 years, caused by the reservoir effect. Therefore, we stress the need for taking into account -and correcting whenever possible- such a deviation before using samples of marine origin for chronological purposes.

    La excavación del castro de O Achadizo (Boiro, A Coruña puso al descubierto una serie de estructuras domésticas, así como varios basureros, encuadrables todos ellos dentro de la cultura castreña del Noroeste ibérico. El hecho de poder disponer de una gran cantidad de material orgánico procedente de los distintos niveles de habitación ha permitido llevar a cabo un programa sistemático de datación mediante el radiocarbono. Como resultado de los análisis radiométricos se deduce que la principal ocupación del yacimiento tuvo lugar entre los siglos VI al II cal BC. Por otra parte hemos cotejado las dataciones obtenidas sobre muestras con la misma procedencia estratigráfica, de origen terrestre (huesos y carbones y oceánico (conchas, a fin de evaluar el efecto de reserva marina. El valor medio de la edad aparente de las conchas de O Achadizo (316 ±19 es semejante al calculado para la costa portuguesa y subraya la necesidad de efectuar una corrección de las dataciones hechas sobre material orgánico de origen marino.

  4. Radiocarbon dating of charred human bone remains preserved in urns excavated from medieval Buddhist cemetery in Japan

    Energy Technology Data Exchange (ETDEWEB)

    Nakamura, Toshio, E-mail: nakamura@nendai.nagoya-u.ac.j [Center for Chronological Research, Nagoya University, Chikusa, Nagoya 464-8602 (Japan); Sagawa, Shinichi; Yamada, Tetsuya [Gangoji Institute for Research of Cultural Properties, Nakain, Nara 630-8392 (Japan); Kanehara, Masaaki [School of Science Education, Nara University of Education, Takabatake, Nara 630-8528 (Japan); Tsuchimoto, Norio [Ichinomiya City Museum, Yamato, Ichinomiya 491-0922 (Japan); Minami, Masayo [Center for Chronological Research, Nagoya University, Chikusa, Nagoya 464-8602 (Japan); Omori, Takayuki [Graduate School of Environmental Studies, Nagoya University, Chikusa, Nagoya 464-8602 (Japan); Okuno, Mitsuru [Faculty of Science, Fukuoka University, Jonan, Fukuoka 814-0180 (Japan); Ohta, Tomoko [Center for Chronological Research, Nagoya University, Chikusa, Nagoya 464-8602 (Japan)

    2010-04-15

    For a preliminary test of {sup 14}C dating of cremated human remains, we have collected charred bone and wood-charcoal fragments from cremated remains contained in cinerary urns that had been excavated from medieval Buddhist cemetery at the Hoenji temple in Aichi prefecture, central Japan. More than 230 urn vessels were discovered from the excavated area of ca. 14 m wide and 14 m long. The identification of charred bone or charcoal fragments among the remains was performed by observation of surface appearance, inspection of fine structures by a microscope, bubble formation during the HCl treatments in preparing target material for AMS {sup 14}C dating, carbon and nitrogen contents, delta{sup 13}C and delta{sup 15}N values of the fragments. All {sup 14}C ages obtained for the samples that were identified as charred bone remains were almost consistent with the archeological age estimated based on typological analysis of respective urns. On the other hand, some {sup 14}C ages for the remains identified as wood charcoal, which had been produced from firewood or a wooden coffin during the cremation, were not consistent with archeological estimation, shifting toward older {sup 14}C ages, most probably as the result of old wood effect.

  5. Radiocarbon dating of dissolved inorganic carbon in groundwater from confined parts of the Upper Floridan aquifer, Florida, USA

    Science.gov (United States)

    Plummer, Niel; Sprinkle, Craig

    2001-03-01

    Geochemical reaction models were evaluated to improve radiocarbon dating of dissolved inorganic carbon (DIC) in groundwater from confined parts of the Upper Floridan aquifer in central and northeastern Florida, USA. The predominant geochemical reactions affecting the 14C activity of DIC include (1) dissolution of dolomite and anhydrite with calcite precipitation (dedolomitization), (2) sulfate reduction accompanying microbial degradation of organic carbon, (3) recrystallization of calcite (isotopic exchange), and (4) mixing of fresh water with as much as 7% saline water in some coastal areas. The calculated cumulative net mineral transfers are negligibly small in upgradient parts of the aquifer and increase significantly in downgradient parts of the aquifer, reflecting, at least in part, upward leakage from the Lower Floridan aquifer and circulation that contacted middle confining units in the Floridan aquifer system. The adjusted radiocarbon ages are independent of flow path and represent travel times of water from the recharge area to the sample point in the aquifer. Downgradient from Polk City (adjusted age 1.7 ka) and Keystone Heights (adjusted age 0.4 ka), 14 of the 22 waters have adjusted 14C ages of 20-30 ka, indicating that most of the fresh-water resource in the Upper Floridan aquifer today was recharged during the last glacial period. All of the paleowaters are enriched in 18O and 2H relative to modern infiltration, with maximum enrichment in δ18O of approximately 2.0‰. Résumé. Les modèles de réactions géochimiques ont été évalués afin de tester la datation par le radiocarbone du carbone minéral dissous (CMD) des eaux souterraines dans les parties captives de la nappe supérieure de Floride, en Floride centrale et nord-orientale (États-Unis). Les réactions géochimiques prédominantes affectant l'activité en 14C du CMD comprennent (1) la dissolution de la dolomite et de l'anhydrite accompagnée de la précipitation de la calcite (d

  6. Atmospheric radiocarbon variations 11,000 years ago

    Energy Technology Data Exchange (ETDEWEB)

    Hajdas, I.; Bonani, G. [Eidgenoessische Technische Hochschule, Zurich (Switzerland); Peteet, D. [LDEO of Columbia Univ. (United States); Boden, P. [Stockholm Univ. (Sweden)

    1997-09-01

    Records of climate changes were {sup 14}C dated using AMS method. High resolution dating allowed reconstruction of the atmospheric {sup 14}C variations at the time of deglaciation. An abrupt rise of up to 100%o in the atmospheric {sup 14}C/{sup 12}C ratio was found at 11`000 BP (radiocarbon age) which coincides with the limit of an abrupt cooling and a decrease in ocean ventilation. (author) 1 fig., 6 refs.

  7. New biomedical applications of radiocarbon

    Energy Technology Data Exchange (ETDEWEB)

    Davis, J.C.

    1990-12-01

    The potential of accelerator mass spectrometry (AMS) and radiocarbon in biomedical applications is being investigated by Lawrence Livermore National Laboratory (LLNL). A measurement of the dose-response curve for DNA damage caused by a carcinogen in mouse liver cells was an initial experiment. This demonstrated the sensitivity and utility of AMS for detecting radiocarbon tags and led to numerous follow-on experiments. The initial experiment and follow-on experiments are discussed in this report. 12 refs., 4 figs. (SM)

  8. Environmental changes in the western Amazônia: morphological framework, geochemistry, palynology and radiocarbon dating data.

    Science.gov (United States)

    Horbe, Adriana M C; Behling, Hermann; Nogueira, Afonso C R; Mapes, Russell

    2011-09-01

    The sediments from the Coari lake, a "terra firme" lake sculpted into Plio-Pleistocene deposits, and the Acará lake, a flooding-type lake developed on Quaternary sediments in the floodplain of the mid-Solimões river, in the western Amazônia, Brazil, were studied to investigate the environmental condition of their developing. This study includes mineral composition, geochemistry, Pb isotope, palinology, radiocarbon-age and morphological framework of the lakes obtained from SRTM satellite images. The geological and the environmental conditions in the two lakes are highly variable and suggest that their evolution reflect autogenic processes under humid rainforest condition. Although kaolinite, quartz, muscovite, illite, and smectite are the main minerals in both lakes, the geochemistry indicates distinct source, the Acará lake sediments have higher concentrations of Al(2)O(3), Fe(2)O(3), FeO, CaO, K(2)O, MgO, Na(2)O, P(2)O(5), Ba, V, Cu, Ni, Zn, Pb, Sr, Li, Y and La and have more radiogenic Pb than the Coari lake sediments. The radiocarbon ages suggest that at 10160 yr BP the Coari lake started to be developed due to avulsion of the Solimões river, and the Acará lake was formed by the meander abandonment of Solimões river retaining its grass dominated shore at ca. 3710 yr BP.

  9. Radiocarbon dating of ancient Japanese calligraphy sheets and the discovery of 45 letters of a lost manuscript

    Energy Technology Data Exchange (ETDEWEB)

    Oda, H. [Nagoya Univ. (Japan). Center for Chronological Research; Yasu, H. [Taga High School, Hitachi, Ibaragi (Japan); Ikeda, K. [Chuo Univ., Tokyo (Japan). Faculty of Letters; Sakamoto, M. [National Museum of Japanese History, Sakura, Chiba (Japan); Yoshizawa, Y.

    2011-07-01

    The Miidera-gire is an ancient paper sheet with different, elegant calligraphy on both sides. One side contains a part of a Buddhist scripture from around the ninth to the twelfth century and written in cursive hand, while the other side contains a part of Monzen (an anthology of Chinese literary works). The paleographical style of this Monzen seems to be older than that of the Buddhist scripture and is similar to some Chinese manuscripts written in the Tang Dynasty (AD 618-907). However, amid these elegant calligraphic writings, there exist many copies and counterfeits that were written several centuries later. We, therefore, measured the radiocarbon age of the Miidera-gire by using accelerator mass spectrometry. The calibrated radiocarbon age indicated 666-776 [cal AD] (2{sigma} error), thus leading to the conclusion that the Monzen was first written on the obverse side, and long afterwards, the Buddhist scripture was written on the reverse side. Since only a few incomplete books of Monzen were written before the ninth century, this calligraphy is one of the oldest of the existing Monzen manuscripts. (orig.)

  10. Radiocarbon dates of late quaternary mammals in the Archangelsk Region and their contribution to reconstructions of the last glaciation in Eastern Europe

    NARCIS (Netherlands)

    Ponomarev, D. V.; Markova, A. K.; van Kolfschoten, T.; van der Plicht, J.; Yushkin, N.P.

    2012-01-01

    Twelve new AMS (Accelerator Mass Spectrometry) dates of large Quaternary mammal remains were reported: mammoth (Mammuthus primigenius, bison (Bison priscus), and musk ox (Ovibos pallantis) found in the Archangelsk Region. The absolute age of the identified samples varies from 46 000 to 22 000 calibr

  11. Errors in generating time-series and in dating events at late quaternary millenial (radiocarbon) time-scales: Examples from Baffin Bay, NW Labrador Sea, and East Greenland

    Science.gov (United States)

    Andrews, John T.; Barber, Donald C.; Jennings, Anne E.

    A crucial question to understand the climate system at millennial time-scales is whether we can detect leads and lags. We examine errors on downcore age data sets resulting from the application of two depth/radiocarbon age models: 1) interpolation between dates, versus 2) ordinary least squares (OLS) regression. In areas affected by changes in sediment accumulation rates, interpolation between dates on facies boundaries would seem most appropriate, whereas in areas of constant sedimentation OLS regression would seem appropriate. We estimated the ages of 50 and 21 data points respectively, from cores HU87033-009 and HU93030-007 (both with rates of sediment accumulation ca. 30-40 cm/ky) using the two age models. Both cores show intervals of increased sediment accumulation associated with iceberg rafting events possibly coeval with H-1, -2 and -3(?). The two age models produced average age differences of 0.88 ky in HU87033-009 and 0.48 ky in HU93030-007. Monte Carlo simulation experiments indicated that the interpolation method consistently resulted in the larger errors. We then examine the age distribution for the basal ages of two detrital carbonate (DC) "events" in Baffin Bay and the NW Labrador Sea, including H-1, and show that errors on dating the onset of these events are considerable (˜± 300 yrs). We conclude that, when dealing with the generation of millennial time-series and correlation of abrupt events, more attention needs to be given to appropriate age/depth models and attendant errors. This analysis does not take into account the calibration of the radiocarbon time-scale nor bioturbation, both of which can introduce additional errors.

  12. Accelerator mass spectrometry dating at Catalhoeyuek

    Energy Technology Data Exchange (ETDEWEB)

    Goektuerk, E.H. [Dept. of Chemistry, Middle East Technical Univ., Ankara (Turkey); Hillegonds, D.J.; Lipschutz, M.E. [Dept. of Chemistry, Purdue Univ., West Lafayette, IN (United States); Hodder, I. [Dept. of Cultural and Social Anthropology, Standford Univ., Standford, CA (United States)

    2002-07-01

    Several charred plant and charcoal samples from various stratigraphic levels of the Neolithic Site, Catalhoeyuek - Turkey, were dated in the AMS facility of Purdue University (PRIME Lab). Radiocarbon dates reveal a complicated chronology, as was foreseen from archeological investigations. Our measurements suggest that this unique Neolithic town may have been initiated at the East mound around 8390 BP. (orig.)

  13. Development of a nanofiltration method for bone collagen 14C AMS dating

    Science.gov (United States)

    Boudin, Mathieu; Boeckx, Pascal; Buekenhoudt, Anita; Vandenabeele, Peter; Van Strydonck, Mark

    2013-01-01

    Radiocarbon dating of bones is usually performed on the collagen fraction. However, this collagen can contain exogenous molecules, including humic substances (HSs) and/or other soil components that may have a different age than the bone. Incomplete removal can result in biased 14C dates. Ultrafiltration of collagen, dissolved as gelatin (molecular weight (MW) ∼100,000 Dalton), has received considerable attention to obtain more reliable dates. Ultrafiltration is an effective method of removal of low-molecular weight contaminants from bone collagen but it does not remove high-molecular weight contaminants, such as cross-linked humic collagen complexes. However, comparative dating studies have raised the question whether this cleaning step itself may introduce contamination with carbon from the filters used. In this study, a nanofiltration method was developed using a ceramic filter to avoid a possible extraneous carbon contamination introduced by the filter. This method should be applicable to various protein materials e.g. collagen, silk, wool, leather and should be able to remove low-molecular and high molecular weight HSs. In this study bone collagen was hot acid hydrolyzed to amino acids and nanofiltrated. A filter with a molecular weight cutoff (MWCO) of 450 Dalton was chosen in order to collect the amino acids in the permeate and the HSs in the retentate. Two pilot studies were set up. Two nanofiltration types were tested in pilot study 1: dead end and cross flow filtration. Humic substance (HS)-solutions with fossil carbon and modern hydrolyzed collagen contaminated with HSs were filtrated and analyzed with spectrofluorescence to determine the HS removal. Cross flow nanofiltration showed the most efficient HS removal. A second pilot study based upon these results was set up wherein only cross flow filtration was performed. 14C measurements of the permeates of hydrolyzed modern collagen contaminated with fossil HSs demonstrate a significant but incomplete

  14. Development of a nanofiltration method for bone collagen {sup 14}C AMS dating

    Energy Technology Data Exchange (ETDEWEB)

    Boudin, Mathieu, E-mail: mathieu.boudin@ugent.be [Royal Institute for Cultural Heritage, Jubelpark 1, B-1000 Brussels (Belgium); Ghent University, Faculty of Bioscience Engineering, Laboratory of Applied Physical Chemistry, Coupure Links 653, B-9000 Ghent (Belgium); Boeckx, Pascal [Ghent University, Faculty of Bioscience Engineering, Laboratory of Applied Physical Chemistry, Coupure Links 653, B-9000 Ghent (Belgium); Buekenhoudt, Anita [Flemish Institute for Technological Research, Separation and Conversion Technology, Boeretang 200, B-2400 Mol (Belgium); Vandenabeele, Peter [Ghent University, Department of Archaeology, Sint-Pietersnieuwstraat 35, B-9000 Ghent (Belgium); Van Strydonck, Mark [Royal Institute for Cultural Heritage, Jubelpark 1, B-1000 Brussels (Belgium)

    2013-01-15

    Radiocarbon dating of bones is usually performed on the collagen fraction. However, this collagen can contain exogenous molecules, including humic substances (HSs) and/or other soil components that may have a different age than the bone. Incomplete removal can result in biased {sup 14}C dates. Ultrafiltration of collagen, dissolved as gelatin (molecular weight (MW) {approx}100,000 Dalton), has received considerable attention to obtain more reliable dates. Ultrafiltration is an effective method of removal of low-molecular weight contaminants from bone collagen but it does not remove high-molecular weight contaminants, such as cross-linked humic collagen complexes. However, comparative dating studies have raised the question whether this cleaning step itself may introduce contamination with carbon from the filters used. In this study, a nanofiltration method was developed using a ceramic filter to avoid a possible extraneous carbon contamination introduced by the filter. This method should be applicable to various protein materials e.g. collagen, silk, wool, leather and should be able to remove low-molecular and high molecular weight HSs. In this study bone collagen was hot acid hydrolyzed to amino acids and nanofiltrated. A filter with a molecular weight cutoff (MWCO) of 450 Dalton was chosen in order to collect the amino acids in the permeate and the HSs in the retentate. Two pilot studies were set up. Two nanofiltration types were tested in pilot study 1: dead end and cross flow filtration. Humic substance (HS)-solutions with fossil carbon and modern hydrolyzed collagen contaminated with HSs were filtrated and analyzed with spectrofluorescence to determine the HS removal. Cross flow nanofiltration showed the most efficient HS removal. A second pilot study based upon these results was set up wherein only cross flow filtration was performed. {sup 14}C measurements of the permeates of hydrolyzed modern collagen contaminated with fossil HSs demonstrate a significant

  15. Radiocarbon dating of archaeological samples (sambaqui) using CO(2) absorption and liquid scintillation spectrometry of low background radiation.

    Science.gov (United States)

    Mendonça, Maria Lúcia T G; Godoy, José M; da Cruz, Rosana P; Perez, Rhoneds A R

    2006-01-01

    Sambaqui means, in the Tupi language, a hill of shells. The sambaquis are archaeological sites with remains of pre-historical Brazilian occupation. Since the sambaqui sites in the Rio de Janeiro state region are older than 10,000 years, the applicability of CO(2) absorption on Carbo-sorb and (14)C determination by counting on a low background liquid scintillation counter was tested. In the present work, sambaqui shells were treated with H(3)PO(4) in a closed vessel in order to generate CO(2). The produced CO(2) was absorbed on Carbo-sorb. On saturation about 0.6g of carbon, as CO(2), was mixed with commercial liquid scintillation cocktail (Permafluor), and the (14)C activity determined by counting on a low background counter, Packard Tricarb 3170 TR/SL, for a period of 1000 mins to enable detection of a radiocarbon age of 22,400 BP. But only samples with ages up to 3500 BP were submitted to the method because the samples had been collected in the municipality of Guapimirim, in archaeological sambaqui-type sites belonging to this age range. The same samples were sent to the (14)C Laboratory of the Centro de Energia Nuclear na Agricultura (CENA/USP) where similar results were obtained.

  16. AMS {sup 14}C dating of wooden anchors and planks excavated from submerged wrecks located at Takashima in Imari Bay, Nagasaki prefecture

    Energy Technology Data Exchange (ETDEWEB)

    Suzuki, Kazuhiro; Oda, Hirotaka; Niu, Etsuko; Ikeda, Akiko; Nakamura, Toshio [Nagoya Univ., Center for Chronological Research, Nagoya, Aichi (Japan); Ogawa, Mitsuhiko [Ryukyus Univ., Graduate School of Humanities and Social Sciences, Course of Regional Cultural Studies, Nishihara, Okinawa (Japan); Matsuo, Akiko [Takashima-town Archeological Center, Takashima, Nagasaki (Japan)

    2001-09-01

    According to folklore the fleet that was dispatched to Japan for the second Mongol invasion of 1281 encountered a fierce typhoon at Takashima. Radiocarbon ({sup 14}C) ages of wooden anchors and planks excavated from the submerged site at Takashima were determined using accelerator mass spectrometry (AMS). The {sup 14}C ages are 745{+-}20 BP for bamboo and 770{+-}20 BP for wood from the intact wooden anchor, and 840{+-}20 / 865{+-}20 BP for the planks, respectively. The calibrated bamboo age of 1268-1284 cal AD and the slightly older age of 1257-1279 cal AD for wood suggest that the wooden anchor was manufactured just before the invasion. The age range of planks (1191-1236 and 1163-1215 cal AD) is consistent with an idea that they are likely to be derived from contemporaneous ships. The high-precision AMS {sup 14}C dating confirms that the wooden anchors and planks are remains of wrecked Mongolian warships that were involved in the second Mongol invasion. (author)

  17. Environmental changes in the western Amazônia: morphological framework, geochemistry, palynology and radiocarbon dating data

    Directory of Open Access Journals (Sweden)

    Adriana M.C. Horbe

    2011-09-01

    Full Text Available The sediments from the Coari lake, a “terra firme” lake sculpted into Plio-Pleistocene deposits, and the Acará lake, a flooding-type lake developed on Quaternary sediments in the floodplain of the mid-Solimões river, in the western Amazônia, Brazil, were studied to investigate the environmental condition of their developing. This study includes mineral composition, geochemistry, Pb isotope, palinology, radiocarbon-age and morphological framework of the lakes obtained from SRTM satellite images. The geological and the environmental conditions in the two lakes are highly variable and suggest that their evolution reflect autogenic processes under humid rainforest condition. Although kaolinite, quartz, muscovite, illite, and smectite are the main minerals in both lakes, the geochemistry indicates distinct source, the Acará lake sediments have higher concentrations of Al2O3, Fe2O3, FeO, CaO, K2O, MgO, Na2O, P2O5, Ba, V, Cu, Ni, Zn, Pb, Sr, Li, Y and La and have more radiogenic Pb than the Coari lake sediments. The radiocarbon ages suggest that at 10160 yr BP the Coari lake started to be developed due to avulsion of the Solimões river, and the Acará lake was formed by the meander abandonment of Solimões river retaining its grass dominated shore at ca. 3710 yr BP.Os sedimentos do lago Coari, de ambiente de terra firme eesculpido nos depósitos do Plio-Pleistocenos, e o Acará, típico lago de várzea e ambos formados nos sedimentos quaternários da planície de inundação do médio Solimões, no oeste da Amazônia, Brasil, foram estudados para investigar as condições ambientais durante sua formação. Este estudo inclui dados da composição mineralógica, química, isótopos de Pb, palinologia, datações de radiocarbono e a configuração morfológica dos lagos obtida por imagens SRTM. As condições geológica e ambiental dos lagos variam e sugerem que suas evoluções refletem processos autogenéticos em condições de floresta úmida

  18. Revised stratigraphy and eruption rates of Ceboruco stratovolcano and surrounding monogenetic vents (Nayarit, Mexico) from historical documents and new radiocarbon dates

    Science.gov (United States)

    Sieron, Katrin; Siebe, Claus

    2008-09-01

    More than a dozen new radiocarbon dates reconstruct the eruptive history of Ceboruco volcano. Six of these further constrain previous results for the important plinian Jala eruption, which occurred near 1060 ± 55 yr BP. A calibrated radiocarbon age of AD 990-1020 was obtained as best overlap range for all samples. Pottery fragments found directly underneath the pumice deposit indicate that this area was inhabited by human populations that witnessed the eruption. This age therefore represents an important time marker in the prehistory of this region, because an area of > 560 km2 was devastated and covered by a thickness of > 50 cm of pumice and ash fallout. After the prominent Jala eruption (VEI = 6), at least seven major lava flows and several smaller domes were issued from Ceboruco's crater. Analysis of historical documents allows us to conclude that most of these eruptions took place well before the arrival of the Spanish conquerors to this area in 1528. Ceboruco's last historic eruption (1870-1872) produced a ca. 7 km long viscous dacite lava flow. Its emplacement was accompanied by block-and-ash flow activity and deposition of ash fallout. Because a repeat of such an eruption in the future would seriously endanger the nearby population and disrupt important life-lines, a detailed discussion of eyewitness accounts and other documents, including drawings and paintings is provided. Some of these materials are made available to the broader public for the first time in the present article. Several surrounding monogenetic vents were previously dated by others using the K-Ar and the Ar-Ar methods. Because these dating methods are often not suitable for very young rocks, we also dated several Holocene monogenetic vents by the radiocarbon method. These dates together with geologic mapping allowed calculating eruption rates and recurrence intervals of different types of eruptions. Accordingly, an andesite/dacite lava flow (accompanied by block-and-ash flow activity) was

  19. Late Quaternary floods and droughts in the Nile valley, Sudan: new evidence from optically stimulated luminescence and AMS radiocarbon dating

    Science.gov (United States)

    Williams, M. A. J.; Williams, F. M.; Duller, G. A. T.; Munro, R. N.; El Tom, O. A. M.; Barrows, T. T.; Macklin, M.; Woodward, J.; Talbot, M. R.; Haberlah, D.; Fluin, J.

    2010-05-01

    Our results show that the late Pleistocene Nile in northern Sudan was shifting position and actively aggrading at 145 ± 20 kyr, 83 ± 24 kyr, 32 ± 8 kyr and 20.7 ± 0.2 kyr and indicate, for the first time, a phase of high-energy flow in the White Nile at 27.8 ± 3.2 kyr, with still high but somewhat reduced flow in that river at 13.3 kyr, 10 kyr and 4.8-4.0 kyr. Beach ridges associated with a 386 m strandline of the White Nile have OSL ages of 27.5 ± 2.7 kyr and 14.5 ± 1.6 kyr. The Holocene terraces and former channels of the main Nile have ages of 11 kyr, 6.5-5.0 kyr and 4.8-4.0 kyr, after which there was a general decline in flood discharge. The now arid main Nile valley in northern Sudan was significantly wetter during the early to middle Holocene, with a lake up to 450 km 2 in area, fed by an overflow channel from the early Holocene Nile between 9.5 kyr and 7.5 kyr. Previously stable late Pleistocene dunes were reactivated at intervals during the Holocene, with five samples from the White Nile valley indicating brief phases of Holocene dune activity at 9.9 ± 2.0 kyr, 9.0 ± 2.8 kyr, 6.6 ± 0.9 kyr, 4.8 ± 0.9 kyr and 2.9 ± 0.5 kyr, the earliest of which occurred within periods of generally wetter climate and higher Nile flow. The youngest freshwater shells on the Khor Abu Habl alluvial fan west of the White Nile correspond to a time of regionally wetter climate between 1.7 and 1.0 kyr. Our results suggest that millennial scale climatic instability may have been characteristic of Holocene climates in this region.

  20. The effects of possible contamination on the radiocarbon dating of the Dead Sea Scrolls I : Castor oil

    NARCIS (Netherlands)

    Rasmussen, KL; van der Plicht, J; Cryer, FH; Doudna, G; Cross, FM; Strugnell, J; Rasmussen, Kaare L.; Cryer, Frederick H.; Cross, Frank M.

    2001-01-01

    Some fragments of the Dead Sea Scroll manuscripts were contaminated with castor oil in the late 1950s. We have conducted experiments in order to establish if the AAA pretreatment cleaning procedures conducted on Dead Sea Scroll manuscript samples in the last two dating series (Bonani et al. 1992; Ju

  1. Concordant 241Pu-241Am Dating of Environmental Samples: Results from Forest Fire Ash

    Science.gov (United States)

    Goldstein, S. J.; Oldham, W. J.; Murrell, M. T.; Katzman, D.

    2010-12-01

    We have measured the Pu, 237Np, 241Am, and 151Sm isotopic systematics for a set of forest fire ash samples from various locations in the western U.S. including Montana, Wyoming, Idaho, and New Mexico. The goal of this study is to develop a concordant 241Pu (t1/2 = 14.4 y)-241Am dating method for environmental collections. Environmental samples often contain mixtures of components including global fallout. There are a number of approaches for subtracting the global fallout component for such samples. One approach is to use 242Pu/239Pu as a normalizing isotope ratio in a three-isotope plot, where this ratio for the non-global fallout component can be estimated or assumed to be small. This study investigates a new, complementary method of normalization using the long-lived fission product, 151Sm (t1/2 = 90 y). We find that forest fire ash concentrates actinides and fission products with ~1E10 atoms 239Pu/g and ~1E8 atoms 151Sm/g, allowing us to measure these nuclides by mass spectrometric (MIC-TIMS) and radiometric (liquid scintillation counting) methods. The forest fire ash samples are characterized by a western U.S. regional isotopic signature representing varying mixtures of global fallout with a local component from atmospheric testing of nuclear weapons at the Nevada Test Site (NTS). Our results also show that 151Sm is well correlated with the Pu nuclides in the forest fire ash, suggesting that these nuclides have similar geochemical behavior in the environment. Results of this correlation indicate that the 151Sm/239Pu atom ratio for global fallout is ~0.164, in agreement with an independent estimate of 0.165 based on 137Cs fission yields for atmospheric weapons tests at the NTS. 241Pu-241Am dating of the non-global fallout component in the forest fire ash samples yield ages in the late 1950’s-early 1960’s, consistent with a peak in NTS weapons testing at that time. The age results for this component are in agreement using both 242Pu and 151Sm normalizations

  2. Progress in AMS measurement of natural {sup 32}Si for glacier ice dating

    Energy Technology Data Exchange (ETDEWEB)

    Morgenstern, Uwe, E-mail: u.morgenstern@gns.cri.n [GNS Science, National Isotope Centre, P.O. Box 30368, Avalon, Lower Hutt (New Zealand); Keith Fifield, L.; Tims, Stephen G. [Department of Nuclear Physics, RSPhysSE, The Australian National University, ACT 0200 (Australia); Ditchburn, Robert G. [GNS Science, National Isotope Centre, P.O. Box 30368, Avalon, Lower Hutt (New Zealand)

    2010-04-15

    AMS measurement of {sup 32}Si can allow for ice core dating over the last thousand years. Technique developments are reported. Necessary negative-ion yields of 20-30% can now be consistently achieved, and permit an overall efficiency from ice sample to detector of approx1%. A {sup 30}Si-spike technique has overcome the problem of extremely low intrinsic silicon concentration, with the added benefit of allowing determination of ppb-level silicon via isotope dilution. Improvements have also been made to the ionization detector in the gas-filled magnet that separates the accelerated {sup 32}Si ions from the intense flux of {sup 32}S ions. Preliminary {sup 32}Si AMS results of snow and ice samples from Mt. Cook National Park, New Zealand, are reproducible, and with {sup 32}Si concentrations 1.2-7.2 mBq/m{sup 3} comparable to results from mid-latitude snow samples measured previously via the radiometric technique, demonstrating the feasibility of the method. With these developments, the potential of {sup 32}Si as ice core dating tool is close to being realized, and attempts to determine chronologies for both alpine and Antarctic glaciers are underway.

  3. AMS {sup 14}C dating at CIRCE: The Major Temple in Cumae (NA – Italy)

    Energy Technology Data Exchange (ETDEWEB)

    Capano, M., E-mail: capano@cerege.fr [Seconda Università degli Studi di Napoli – CIRCE (Centre for Isotopic Research on Cultural and Environmental Heritage), San Nicola la Strada, CE (Italy); Rescigno, C.; Sirleto, R. [Dipartimento di Lettere e Beni Culturali, Seconda Università degli Studi di Napoli, Santa Maria Capua Vetere, CE (Italy); Passariello, I. [INNOVA-CIRCE, San Nicola la Strada, CE (Italy); Marzaioli, F.; D’Onofrio, A.; Terrasi, F. [INNOVA-CIRCE, San Nicola la Strada, CE (Italy); Dipartimento di Matematica e Fisica, Seconda Università degli Studi di Napoli, Caserta (Italy)

    2015-10-15

    We present here one recent CIRCE (Centre for Isotopic Research on Cultural and Environmental Heritage) – Caserta (Italy) project on cultural heritage field, analysing several mice bones, discovered in the Major Temple on the acropolis of Cumae (Napoli, Southern Italy). The bones were found in a vase linked to the holy context. In order to know their dating and formulate an hypothesis on their presence on the site, if it was an accidental rodent inclusion (believed on the base of archaeological context to have occurred during building abandonment periods (IV–V or XIII centuries AD)) or an intentional and ritual remain, the bones were {sup 14}C dated by AMS at CIRCE. The results indicate that the mice bones date to the IV century BC and are contemporaneous with building construction. This dating seems to exclude an accidental rodent presence and it supports the hypothesis of Apollo veneration in the temple, based on the already known link between mice and Apollo worship rituals.

  4. Dating stratified settlement sites at Kom K and Kom W: Fifth millennium BCE radiocarbon ages for the Fayum Neolithic

    Energy Technology Data Exchange (ETDEWEB)

    Wendrich, W. [Department of Near Eastern Languages and Cultures, University of California, Los Angeles, CA 92521 (United States); Cotsen Institute of Archaeology, University of California, Los Angeles, CA 92521 (United States); Taylor, R.E., E-mail: retaylor@ucr.ed [Department of Anthropology, University of California, Riverside, Riverside, CA 92521 (United States); Cotsen Institute of Archaeology, University of California, Los Angeles, CA 92521 (United States); Keck Carbon Cycle Accelerator Mass Spectrometry Laboratory, Department of Earth System Science, University of California, Irvine, CA 92697 (United States); Southon, J. [Keck Carbon Cycle Accelerator Mass Spectrometry Laboratory, Department of Earth System Science, University of California, Irvine, CA 92697 (United States)

    2010-04-15

    The earliest evidence of the use of domesticated plants, a traditional hallmark of Neolithic societies in the ancient Near East, first appears in Egypt in archaeological sites in the Fayum depression. Due to wind erosion often resulting in deflation of sediments in this region, stratified sites containing organic materials are rare and the depositional contexts of some earlier {sup 14}C measurements on Fayum Neolithic materials are not precisely documented. We report the results of 29 AMS-based {sup 14}C determinations on charcoal recovered from stratified contexts in two Fayum Neolithic village sites, Kom K and Kom W. These data assign a mid-5th millennium BCE age to these sites and permit an estimate of the length of their occupation to be approximately three centuries.

  5. Radiocarbon dating of mangrove sediments to constrain Holocene relative sea-level change on Zanzibar in the southwest Indian Ocean.

    OpenAIRE

    2015-01-01

    Mangrove sedimentary deposits are sensitive to changes in sea level and can be used to reconstruct mid- to late Holocene sea-level fluctuations in intermediate and far-field locations, distant to the former polar ice sheets. However, they can be difficult to date using 14C because mangrove sediment can contain mixtures of carbon of different ages. The two main potential causes of error are younger mangrove roots penetrating down through the sediment column and bioturbation by burrowing animal...

  6. Radiocarbon ages of Sorori ancient rice of Korea

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Kyeong Ja, E-mail: kjkim@kigam.re.kr [Korea Institute of Geoscience and Mineral Resources, Daejeon (Korea, Republic of); Lee, Yung-Jo; Woo, Jong-Yoon [Institute of Korean Prehistory, Cheongju (Korea, Republic of); Jull, A.J. Timothy [NSF Arizona AMS Laboratory, University of Arizona, Tucson, AZ 85721 (United States)

    2013-01-15

    Samples of Sorori ancient rice were excavated in 1998 from the Sorori Paleolithic site located at Sorori, Oksan-myeon, Cheong-won County in Chungcheongbuk-do, Korea. We have made new radiocarbon measurements for Sorori samples in 2009 at the NSF Arizona AMS Laboratory. Both ancient rice samples and surrounded peat from the Sorori site were dated. The AMS results confirmed that the ages of the rice and peat soil were 12,520 {+-} 150 and 12,552 {+-} 90 BP, respectively. These radiocarbon ages are consistent with the previously published data of quasi rice measured at Seoul National University and confirm that the Sorori rice is the oldest ancient rice currently reported.

  7. Time since death and decay rate constants of Norway spruce and European larch deadwood in subalpine forests determined using dendrochronology and radiocarbon dating

    Directory of Open Access Journals (Sweden)

    M. Petrillo

    2015-09-01

    Full Text Available Due to the large size and highly heterogeneous spatial distribution of deadwood, the time scales involved in the coarse woody debris (CWD decay of Picea abies (L. Karst. and Larix decidua Mill. in Alpine forests have been poorly investigated and are largely unknown. We investigated the CWD decay dynamics in an Alpine valley in Italy using the five-decay class system commonly employed for forest surveys, based on a macromorphological and visual assessment. For the decay classes 1 to 3, most of the dendrochronological samples were cross-dated to assess the time that had elapsed since tree death, but for decay classes 4 and 5 (poorly preserved tree rings and some others not having enough tree rings, radiocarbon dating was used. In addition, density, cellulose and lignin data were measured for the dated CWD. The decay rate constants for spruce and larch were estimated on the basis of the density loss using a single negative exponential model. In the decay classes 1 to 3, the ages of the CWD were similar varying between 1 and 54 years for spruce and 3 and 40 years for larch with no significant differences between the classes; classes 1–3 are therefore not indicative for deadwood age. We found, however, distinct tree species-specific differences in decay classes 4 and 5, with larch CWD reaching an average age of 210 years in class 5 and spruce only 77 years. The mean CWD rate constants were 0.012 to 0.018 yr−1 for spruce and 0.005 to 0.012 yr−1 for larch. Cellulose and lignin time trends half-lives (using a multiple-exponential model could be derived on the basis of the ages of the CWD. The half-lives for cellulose were 21 yr for spruce and 50 yr for larch. The half-life of lignin is considerably higher and may be more than 100 years in larch CWD.

  8. Upper Pleistocene Radiocarbon-Dated Artefacts from the Northern Yukon: Man was in Beringia 27,000 years ago.

    Science.gov (United States)

    Irving, W N; Harington, C R

    1973-01-26

    The evidence presented here indicates that man lived in the eastern part of the Beringian refugium before the peak of the late Wisconsin glaciation (27). He had sharp, stone tools intended for working bone and means of breaking large mammoth bones. Probably he hunted mammoth and caribou, and prepared the skins of the caribou for use as clothing and perhaps shelter. It is possible that he migrated to southern North America, although evidence for the presence of man there prior to the peak of the Wisconsin glaciation is at present in dispute (28). We do not know whether his culture should be classified as Mousteroid or Aurignacoid in Müller-Beck's scheme (23), whose criteria are taken from stone implements of which we have none, although we infer their presence. Our data suggest that in Beringia, and therefore probably in Siberia and the Far East, the transition from Middle Paleolithic to Upper Paleolithic levels of technology occurred at a relatively early date. This raises the larger question: Did the transition from Middle to Upper Paleolithic occur simultaneously in many parts of the world, or did it begin in and spread from one area (23)?

  9. Causal links between Nile floods and eastern Mediterranean sapropel formation during the past 125 kyr confirmed by OSL and radiocarbon dating of Blue and White Nile sediments

    Science.gov (United States)

    Williams, M. A. J.; Duller, G. A. T.; Williams, F. M.; Woodward, J. C.; Macklin, M. G.; El Tom, O. A. M.; Munro, R. N.; El Hajaz, Y.; Barrows, T. T.

    2015-12-01

    It has long been hypothesised that beds of highly organic mud or sapropels seen in marine sediment cores retrieved from the floor of the eastern Mediterranean accumulated during times of high Nile fluvial discharge. Our recent fieldwork in the valleys of the Blue Nile, the White Nile and the main Nile has for the first time revealed a sequence of extreme flood episodes synchronous with sapropel units S5 (124 kyr), S4 (102 kyr), S3 (81 kyr), S2 (55 kyr) and S1 (13.5-6.5 kyr). There are more weakly defined links with Nile floods and sapropel units S9 (240 kyr), S8 (217 kyr), S7 (195 kyr), S6 (172 kyr), but the dating error terms are too large to allow us to be too definite. During times of extreme floods over the past 125 kyr, wide distributary channels of the Blue Nile flowed across the Gezira alluvial fan in central Sudan and transported a bed load of sand and gravel into the lower White Nile valley. The sands were reworked by wind to form source-bordering dunes, all of which contain heavy minerals of Ethiopian provenance. These source-bordering dunes were active at 115-105 kyr, 60 kyr and 12-7 kyr, all times of extreme Blue Nile floods. The flood and dune sediments were dated using a combination of optically stimulated luminescence (OSL) and radiocarbon analyses. The Quaternary record of Nile floods discussed here shows a precessional signal and reflects episodes of stronger summer monsoon and more northerly seasonal movement of the ITCZ, linked to times of higher insolation in northern tropical latitudes. Progressive aggradation of Holocene Nile channels in northern Sudan has had a profound influence upon human settlement in the last 8 kyr.

  10. Palaeoecological caracterisation of the mammoth steppe at Final Pleistocene in Central Ukraine from zooarchaeology, stable isotope analyses and direct radiocarbon dating

    Science.gov (United States)

    Péan, Stéphane; Drucker, Dorothée.; Bocherens, Hervé; Haesaerts, Paul; Valladas, Hélène; Stupak, Dmytro; Nuzhnyi, Dmytro

    2010-05-01

    that a modification of the regional plant and climatic context may have inferred a change of food resource for mammoths, which could have been put into food competition with horses. Mammoths from Central Ukraine at late OIS 2 may have formed an isolated local population, under the pressure of modified ecological conditions, compared to the period of maximal extension of the mammoth steppe. Thus, thanks to a combined approach of zooarchaeology, stable isotopes and radiocarbon dating, in the stratigraphic context, a better knowledge of the palaeoecological context of the last mammoths at late Pleniglacial in Central Ukraine is expected.

  11. Map of Western Copper River Basin, Alaska, Showing Lake Sediments and Shorelines, Glacial Moraines, and Location of Stratigraphic Sections and Radiocarbon-Dated Samples

    Science.gov (United States)

    Williams, John R.; Galloway, John P.

    1986-01-01

    The purpose of this report is to make available basic data on radiocarbon dating of 61 organic samples from 40 locations in the western Copper River Basin and adjacent uplands and in the uppermost Matanuska River Valley. The former distribution of late Quaternary glacial lakes and of glaciers as mapped from field work and photo interpretation is provided as background for interpretation of the radiocarbon dates and are the basic data needed for construction of the late Quaternary chronology. The glacial boundaries, formed and expressed by moraines, ice-contact margins, marginal channels, deltas, and other features, are obscured by a drape of glaciolacustrine deposits in a series of glacial lakes. The highest lake, represented by bottom sediments as high as 914 m to 975 m above sea level, extends from Fog Lakes lowland on Susitna River upstream into the northwestern part of the Copper River Basin (the part now draining to Susitna River) where it apparently was held in by an ice border. It was apparently dammed by ice from the Mt. McKinley area, by Talkeetna G1acier, and may have had a temporary drainage threshold at the headwaters of Chunilna Creek. No shorelines have been noted within the map area, although Nichols and Yehle (1961) reported shorelines within the 914-975 m range in the Denali area to the north of that mapped. Recent work by geologic consultants for the Susitna Hydroelectric Project has confirmed the early inferences (Karlstrom, 1964) about the existence of a lake in the Susitna canyon, based originally on drilling by the Bureau of Reclamation about 35 years ago. According to dating of deposits at Tyone Bluff (map locations 0, P), Thorson and others (1981) concluded that a late Wisconsin advance of the glaciers between 11,535 and 21,730 years ago was followed by a brief interval of lacustrine sedimentation, and was preceded by a long period of lake deposition broken by a lowering of the lake between 32,000 and about 25,000 years ago. An alternate

  12. RICH – A new AMS facility at the Royal Institute for Cultural Heritage, Brussels, Belgium

    Energy Technology Data Exchange (ETDEWEB)

    Boudin, Mathieu; Van Strydonck, Mark; Brande, Tess van den [Royal Institute for Cultural Heritage, Jubelpark 1, 1000 Brussels (Belgium); Synal, Hans-Arno; Wacker, Luckas [Laboratory of Ion Beam Physics, ETH Zurich, 8093 Zurich (Switzerland)

    2015-10-15

    Since 1989 the radiocarbon dating lab has their own graphitization system for {sup 14}C AMS dating but RICH (Royal Institute for Cultural Heritage) did not possess their own AMS and measurements were carried out in collaboration with other AMS facilities. In April 2013 the Micadas (Mini Carbon Dating System) AMS was installed at RICH in Brussels and after 1.5 year operation the high stability and performance of the Micadas can be demonstrated by repeated analyses of primary standard OXA II and secondary standards. Results of unknown samples measured on the RICH–Micadas and on other AMS systems are in good agreement.

  13. Evolution of chemical and isotopic composition of inorganic carbon in a complex semi-arid zone environment: Consequences for groundwater dating using radiocarbon

    Science.gov (United States)

    Meredith, K. T.; Han, L. F.; Hollins, S. E.; Cendón, D. I.; Jacobsen, G. E.; Baker, A.

    2016-09-01

    Estimating groundwater age is important for any groundwater resource assessment and radiocarbon (14C) dating of dissolved inorganic carbon (DIC) can provide this information. In semi-arid zone (i.e. water-limited environments), there are a multitude of reasons why 14C dating of groundwater and traditional correction models may not be directly transferable. Some include; (1) the complex hydrological responses of these systems that lead to a mixture of different ages in the aquifer(s), (2) the varied sources, origins and ages of organic matter in the unsaturated zone and (3) high evaporation rates. These all influence the evolution of DIC and are not easily accounted for in traditional correction models. In this study, we determined carbon isotope data for; DIC in water, carbonate minerals in the sediments, sediment organic matter, soil gas CO2 from the unsaturated zone, and vegetation samples. The samples were collected after an extended drought, and again after a flood event, to capture the evolution of DIC after varying hydrological regimes. A graphical method (Han et al., 2012) was applied for interpretation of the carbon geochemical and isotopic data. Simple forward mass-balance modelling was carried out on key geochemical processes involving carbon and agreed well with observed data. High values of DIC and δ13CDIC, and low 14CDIC could not be explained by a simple carbonate mineral-CO2 gas dissolution process. Instead it is suggested that during extended drought, water-sediment interaction leads to ion exchange processes within the top ∼10-20 m of the aquifer which promotes greater calcite dissolution in saline groundwater. This process was found to contribute more than half of the DIC, which is from a mostly 'dead' carbon source. DIC is also influenced by carbon exchange between DIC in water and carbonate minerals found in the top 2 m of the unsaturated zone. This process occurs because of repeated dissolution/precipitation of carbonate that is dependent on

  14. Accuracy of radiocarbon analyses at ANTARES

    Energy Technology Data Exchange (ETDEWEB)

    Lawson, E.M.; Fink, D.; Hotchkis, M.; Hua, Q.; Jacobsen, G.; Smith, A.M.; Tuniz, C. [Australian Nuclear Science and Technology Organisation, Lucas Heights, NSW (Australia)

    1996-12-31

    Accuracy in Accelerator Mass Spectroscopy (AMS) measurements, as distinct from precision, requires the application of a number of corrections. Most of these are well known except in extreme circumstances and AMS can deliver radiocarbon results which are both precise and accurate in the 0.5 to 1.0% range. The corrections involved in obtaining final radiocarbon ages are discussed. 3 refs., 1 tab.

  15. Mid- to Late-Holocene estuarine infilling processes studied by radiocarbon dates, high resolution seismic and biofacies at Vitoria Bay, Espirito Santo, Southeastern Brazil

    Directory of Open Access Journals (Sweden)

    Alex C. Bastos

    2010-09-01

    Full Text Available Vitoria Bay is a 20 km long estuary, morphologically narrow, with a microtidal regime and, as other modern estuaries, was formed during the last post-glacial transgression. The estuarine bed morphology is characterised by a main natural channel limited by tidal flats with developed mangroves. Original radiocarbon dates were obtained for the site. Five radiocarbon ages ranging from 1,010 to 7,240 years BP were obtained from two sedimentary cores, which represent a 5 m thick stratigraphic sequence. The results indicate that, until about 4,000 cal. yrs BP, environmental conditions in Vitoria Bay were still of an open bay, with a free and wide connection with marine waters. During the last 4,000 yrs, the bay has experienced a major regression phase, by becoming more restricted in terms of seawater circulation and probably increasing tidal energy. Three main stratigraphic surfaces were recognised, which limit trangressive, trangressive/highstand and regressive facies. The present channel morphology represents a tidal scouring surface or a tidal diastem, which erodes and truncates regressive facies bedding. Foraminiferal biofacies, which change from marine to brackish and mangrove tidal-flat environments, support the seismic stratigraphic interpretation. Absence of mangrove biofacies at one of the two cores is also an indication of modern tidal ravinement.A Baía de Vitória é um estuário com 20 km de comprimento, morfologicamente estreito, com um regime de micromaré e, como outros estuários modernos, formado durante a última transgressão pós-glacial. A morfologia de fundo do estrato estuarino é caracterizada por um canal natural principal limitado por planícies de maré com manguezais desenvolvidos. Datações de radiocarbono originais foram obtidas para a área. Cinco idades de radiocarbono estendendo-se de 1.010 a 7.240 anos AP foram obtidas através de dois testemunhos de sedimento, representando uma sequência estratigráfica de 5 m de

  16. Radiocarbon dating and wiggle matching of wooden poles forming circular structures in the 1st Millennium BC at the Mawaki archaeological site, central Japan

    Energy Technology Data Exchange (ETDEWEB)

    Nishimoto, Hiroshi, E-mail: momo@nendai.nagoya-u.ac.j [Graduate School of Environmental Studies, Nagoya University, Nagoya Aichi 464-8602 (Japan); Nakamura, Toshio [Noto-Town Board of Education, Mawaki Noto-cho, Ishikawa 927-0562 (Japan); Takada, Hideki [Center for Chronological Research, Nagoya University, Nagoya Aichi 464-8602 (Japan)

    2010-04-15

    Wooden circular structures, presumed archaeologically as a structure related with ritual of ancient people in the Final Jomon period, are specific to archaeological sites excavated mainly in the coastal region around Noto peninsula, central Japan. So far, only few attempts have been made at chronological studies on these wooden structures. {sup 14}C dating has been attempted to wooden poles forming the structures, which had been excavated at the Mawaki archaeological site, Ishikawa prefecture, central Japan, to examine construction period of the structures. It was revealed that these structures were constructed in the Final Jomon period, most probably within 900-400 cal BC. In addition, we have tried wiggle matching of {sup 14}C ages for several annual rings separated from three and two poles that were constituting two circular structures, the oldest and the newest ones. {sup 14}C dates of annual rings measured with AMS were wiggle-matched to IntCal04 data sets by Bayesian statistics. The results indicated that the construction period of these wooden structures can be placed within ca. 820-680 cal BC, being narrowed by about 350 calendar years successfully.

  17. Radiocarbon Dates from Volcanic Deposits of the Chaos Crags and Cinder Cone Eruptive Sequences and Other Deposits, Lassen Volcanic National Park and Vicinity, California

    Science.gov (United States)

    Clynne, Michael A.; Christiansen, Robert L.; Trimble, Deborah A.; McGeehin, John P.

    2008-01-01

    This contribution reports radiocarbon ages obtained from charcoal, wood and other samples collected between 1979 and 2001 in Lassen Volcanic National Park and vicinity and a few samples from other nearby localities. Most of the samples are from the Chaos Crags and Cinder Cone eruptive sequences. Brief summaries are given of the Chaos Crags and Cinder Cone eruptive sequences.

  18. Adult Human Pancreatic Islet Beta-Cells Display Limited Turnover and Long Lifespan as Determined by In-Vivo Thymidine Analog Incorporation and Radiocarbon Dating

    Energy Technology Data Exchange (ETDEWEB)

    Perl, S; Kushner, J A; Buchholz, B A; Meeker, A K; Stein, G M; Hsieh, M; Kirby, M; Pechhold, S; Liu, E H; Harlan, D M; Tisdale, J F

    2010-03-15

    Diabetes mellitus results from an absolute or relative deficiency of insulin producing pancreatic beta-cells. The adult human beta-cell's turnover rate remains unknown. We employed novel techniques to examine adult human islet beta-cell turnover and longevity in vivo. Subjects enrolled in NIH clinical trials received thymidine analogues [iododeoxyuridine (IdU) or bromodeoxyuridine (BrdU)] 8-days to 4-years prior to death. Archival autopsy samples from ten patients (aged 17-74 years) were employed to assess beta-cell turnover by scoring nuclear analog labeling within insulin staining cells. Human adult beta-cell longevity was determined by estimating the cells genomic DNA integration of atmospheric carbon-14 ({sup 14}C). DNA was purified from pancreatic islets isolated from cadaveric donors; whole islet prep DNA was obtained from a 15 year old donor, and purified beta-cell DNA was obtained from two donors (age 48 and 80 years). {sup 14}C levels were then determined using accelerator mass spectrometry (AMS). Cellular 'birth date' was determined by comparing the subject's DNA {sup 14}C content relative to a well-established {sup 14}C atmospheric prevalence curve. In the two subjects less than age 20 years, 1-2% of the beta-cell nuclei co-stained for BrdU/IdU. No beta-cell nuclei co-stained in the eight patients more than 30 years old. Consistent with the BrdU/IdU turnover data, beta-cell DNA {sup 14}C content indicated the cells 'birth date' occurred within the subject's first 30 years of life. Under typical circumstances, adult human beta-cells and their cellular precursors are established by young adulthood.

  19. Erosion of soil organic carbon at high latitudes and its delivery to Arctic Ocean sediments: New source to sink insight from radiocarbon dating

    Science.gov (United States)

    Hilton, Robert; Galy, Valier; Gaillardet, Jerome; Dellinger, Mathieu; Bryant, Charlotte; O'Regan, Matt; Grocke, Darren; Coxall, Helen

    2016-04-01

    Soils of the northern high latitudes store carbon over thousands of years and contain almost double the carbon stock of the atmosphere. Erosion processes can mobilise this pre-aged soil organic carbon from the landscape and supply it to rivers. If it escapes degradation during river transport and is delivered to the coastal ocean, this carbon may be sequestered for much longer periods of time (>104 yr) as a geological CO2 sink. Despite this recognition, the erosional flux and fate of particulate organic carbon (POC) in large rivers draining the high latitudes remains poorly constrained. Using radiocarbon activity, we quantify POC source, flux and fate in the Mackenzie River, the main sediment supplier to the Arctic Ocean. When combined with stable carbon isotopes and element ratios, the radiocarbon activity of POC allows us to distinguish inputs of POC from sedimentary rocks and quantify the average age of biospheric POC (from vegetation and soil) transported through the river system. We find that the eroded biospheric POC has resided in the basin for millennia, with a mean radiocarbon age of 5800±800 years. This is much older than large tropical rivers where we have equivalent data (Amazon River, Ganges River), and likely reflects the longer residence time of organic matter in cold, wet, high latitude soils. Based on the measured biospheric POC content and annual sediment flux, we calculate a biospheric POC flux of 2.2 (+1.3/-0.9) TgC yr-1 from the Mackenzie River. This is the largest input of aged organic carbon to the Arctic Ocean, more than the combined POC flux from the Eurasian Rivers. Offshore, we use a marine core to investigate organic carbon burial over the Holocene period. Radiocarbon measurements of bulk organic carbon reveal a significant offset from benthic foraminifera radiocarbon ages throughout the core, which is dependent upon the grain size of the sediments. Organic matter in sediments >63μm are offset from foraminifera by ˜ 6,000 14C years

  20. Radiocarbon Values From Otoliths of Regional Bottomfishes

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The data set contains bomb radiocarbon dating of opakapaka (Pristipomoides filamentosus) otoliths from recent and archival collections (1978-2008). Specimens were...

  1. Intercomparison of radiocarbon bomb pulse and 210Pb age models. A study in a peat bog core from North Poland

    Science.gov (United States)

    Piotrowska, Natalia; De Vleeschouwer, François; Sikorski, Jarosław; Pawlyta, Jacek; Fagel, Nathalie; Le Roux, Gaël; Pazdur, Anna

    2010-04-01

    Radiocarbon and 210Pb were measured on the uppermost 40 cm of a Wardenaar peat core retrieved from a Baltic raised bog at Słowińskie Błota (Pomerania, North Poland). This site is the subject of ongoing multiproxy studies covering the last 1300 years. Radiocarbon age model was constructed on the basis of 14 AMS dates obtained on selected Sphagnum spp. fragments, with use of P_Sequence tool. We present here a comparison of this model with the age model obtained using CRS model classically applied to 210Pb measurements.

  2. Influence of self-absorption corrections in the quantification of 210Pb and 241Am for sediment dating

    Science.gov (United States)

    González, J. Carrazana; Vargas, M. Jurado; Castillo, R. Gil

    2016-10-01

    The nuclides 210Pb and 241Am are used in geochronological studies. In this work, we examine the influence of the sediment chemical composition on the self-attenuation corrections needed for the accurate determination of specific activities for 210Pb and 241Am used for sediment dating. A theoretical exercise was carried out evaluating the relative bias obtained by four different analytical laboratories in the quantification of the 210Pb and 241Am activity concentration by gamma-ray spectrometry. The laboratories considered the same density for the sediment sample, but each one used a different chemical composition in the Monte Carlo calculations, and six different HPGe detectors (including n and p-types). An estimate of the impact that would have the relative biases found in the estimation of the 210Pb sediment ages, applying the Constant Rate of Supply (CRS) dating model, is also given. In addition, the performance scores that the laboratories would have obtained in a hypothetical IAEA proficiency test are also presented.

  3. ESR and AMS-based C-14 dating of Mousterian levels at Mujina Pecina, Dalmatia, Croatia

    NARCIS (Netherlands)

    Rink, WJ; Karavanic, [No Value; Pettitt, PB; Van der Plicht, J; Smith, FH; Bartoll, J

    2002-01-01

    This paper presents the first chronometric dates for sediments that contain a Mousterian industry in Dalmatia (south Croatia). Electron spin resonance (ESR) dating was conducted on two teeth from the Mousterian level E1 at the site of Mujina Pecina. Additionally five bone and one charcoal sample fro

  4. Bringing AMS radiocarbon into the Anthropocene: Potential and drawbacks in the determination of the bio-fraction in industrial emissions and in carbon-based products

    Energy Technology Data Exchange (ETDEWEB)

    Quarta, Gianluca, E-mail: gianluca.quarta@unisalento.it [CEDAD (Centre for Dating and Diagnostics), Department of Engineering for Innovation, University of Salento (Italy); Ciceri, Giovanni; Martinotti, Valter [Ricerca sul Sistema Energetico SpA, Milan (Italy); D’Elia, Marisa; Calcagnile, Lucio [CEDAD (Centre for Dating and Diagnostics), Department of Engineering for Innovation, University of Salento (Italy)

    2015-10-15

    In the frame of the general efforts to reduce atmospheric CO{sub 2} emissions different efforts are being carried out to stimulate the use of non-fossil energy sources and raw materials. Among these a significant role is played by the use of waste in Waste to Energy (WTE) plants. In this case a relevant problem is related to the determination of the proportion between the bio and the fossil derived fraction in CO{sub 2} atmospheric emissions since only the share of energy derived from the bio-fraction combustion can be labelled as “renewable”. We discuss the potential of radiocarbon in this field by presenting the results of different campaigns carried out by analysing CO{sub 2} sampled at the stack of different power plants in Italy with different expected bio-content of the released carbon dioxide. The still open issues related to the calculation procedures and the achievable precision and accuracy levels are discussed.

  5. Le programme ARTEMIS : nouvel outil pour la datation radiocarbone AMS (Spectromètre de Masse par Accélérateur et nouvelles problématiques

    Directory of Open Access Journals (Sweden)

    Cyrille Billard

    2012-04-01

    Full Text Available La mise en route du nouvel équipement ARTEMIS (Accélérateur pour la Recherche en sciences de la Terre, Environnement, Muséologie, Implanté à Saclay à partir de 2004 ouvre de nouvelles perspectives scientifiques et conduit à de nouvelles procédures de soumission des échantillons destinés à une datation 14C. Le MCC dispose aujourd’hui de droits alloués aux services régionaux de l'archéologie, services du ministère de la Culture, confrontés à ce type de demandes (musées, monuments historiques. Il impose désormais une nouvelle démarche de programmation scientifique des datations, associant une analyse critique des demandes.Since 2004, the availability at Saclay of a new ARTEMIS installation (Accélérateur pour la Recherche en sciences de la Terre, Environnement, Muséologie has opened new scientific perspectives and led to new procedures for submitting samples for carbon-14 dating. The French Ministry of Culture has the possibility of using this tool for radiocarbon dating at the request of its regional archaeological services or other services, such as museums and the historic monuments administration. This use now implies a new approach to the scientific planning for dating problems, associated with a critical analysis of the requests.

  6. Dating Danish textiles and skins from bog finds by means of 14C AMS

    DEFF Research Database (Denmark)

    Mannering, Ulla; Possnert, Göran; Heinemeier, Jan;

    2010-01-01

    This paper presents the results of 44 new 14C analyses of Danish Early Iron Age textiles and skins. Of 52 Danish bog finds containing skin and textile items, 30 are associated with bog bodies. Until now, only 18 of these have been dated. In this paper we add dates to the remaining finds....... The results demonstrate that the Danish custom of depositing clothed bodies in a bog is centred to the centuries immediately before and at the beginning of the Common Era. Most of these bodies are carefully placed in the bog - wrapped or dressed in various textile and/or skin garments....

  7. Identifying sources of dissolved organic carbon in agriculturally dominated rivers using radiocarbon age dating: Sacramento-San Joaquin River Basin, California

    Science.gov (United States)

    Sickman, James O.; DiGiorgio, Carol L.; Davisson, M. Lee; Lucero, Delores M.; Bergamaschi, Brian A.

    2010-01-01

    We used radiocarbon measurements of dissolved organic carbon (DOC) to resolve sources of riverine carbon within agriculturally dominated landscapes in California. During 2003 and 2004, average Δ14C for DOC was -254‰ in agricultural drains in the Sacramento-San Joaquin Delta, -218‰ in the San Joaquin River, -175‰ in the California State Water Project and -152‰ in the Sacramento River. The age of bulk DOC transiting the rivers of California's Central Valley is the oldest reported for large rivers and suggests wide-spread loss of soil organic matter caused by agriculture and urbanization. Using DAX 8 adsorbent, we isolated and measured 14C concentrations in hydrophobic acid fractions (HPOA); river samples showed evidence of bomb-pulse carbon with average Δ14C of 91 and 76‰ for the San Joaquin and Sacramento Rivers, respectively, with older HPOA, -204‰, observed in agricultural drains. An operationally defined non-HPOA fraction of DOC was observed in the San Joaquin River with seasonally computed Δ14C values of between -275 and -687‰; the source of this aged material was hypothesized to be physically protected organic-matter in high clay-content soils and agrochemicals (i.e., radiocarbon-dead material) applied to farmlands. Mixing models suggest that the Sacramento River contributes about 50% of the DOC load in the California State Water Project, and agricultural drains contribute approximately one-third of the load. In contrast to studies showing stabilization of soil carbon pools within one or two decades following land conversion, sustained loss of soil organic matter, occurring many decades after the initial agricultural-land conversion, was observed in California's Central Valley.

  8. First direct dating of Late Pleistocene ice-wedges by AMS

    NARCIS (Netherlands)

    Vasil'chuk, YK; van der Plicht, J; Jungner, H; Sonninen, E; Vasil'chuk, AC; Vasil'chuk, Yurij K.; Vasil'chuk, Alla C.

    2000-01-01

    We present the first direct dating by C-14-accelerator mass spectrometry of three Late Pleistocene syngenetic ice-wedges from the Seyaha cross-section. They are representative of permafrost with multistage ice-wedges from the North of Western Siberia. The most important result is the clear vertical

  9. The new extended HVE 1 MV multi-element AMS system for low background installed at the Aarhus AMS Dating Centre

    Energy Technology Data Exchange (ETDEWEB)

    Heinemeier, Jan; Olsen, Jesper [AMS " 1" 4C Dating Centre, Department of Physics and Astronomy, Aarhus University, Aarhus (Denmark); Klein, Matthias; Mous, Dirk [High Voltage Engineering Europa B.V., Amersfoort (Netherlands)

    2015-10-15

    Aarhus University, Department of Physics and Astronomy has installed a new multi-element AMS system at its AMS {sup 14}C Dating Centre. It is manufactured by High Voltage Engineering Europa B.V. and based on a 1 MV Tandetron accelerator with a dual gas system (Ar and He) for the terminal stripper. The injector is equipped with two independently operating ion sources and a 120 degree bouncer magnet with high resolution and a bending power of 340 amu at 35 keV, supporting the measurements of actinides. The high-energy (HE) spectrometer features a degrader foil for isobar suppression and a second HE magnet for suppression of ions scattered in the HE ESA, which ensures very low detection limits. The control system supports different methods for isotope switching: “traditional” fast bouncing, adjusting the Hall-probe controlled magnet fields (for, e.g., {sup 3}H), or changing the complete set of operation parameters (e.g., for actinides). During the on-site acceptance tests, the following background levels were measured: <10{sup −16} for tritium, <10{sup −15} for {sup 14}C, <10{sup −15} for {sup 10}Be (down to <10{sup −16} in a later 3 h run), 2 × 10{sup −15} for {sup 26}Al, 2 × 10{sup −13} for {sup 129}I and 9 × 10{sup −12} for {sup 41}Ca and for {sup 239}Pu ({sup 240}Pu) a 1.5 (0.5) pg per mg iron, which demonstrates the multi-element capability of the system.

  10. Manganese-53: Development of the AMS technique for exposure-age dating applications

    Science.gov (United States)

    Gladkis, L. G.; Fifield, L. K.; Morton, C. R.; Barrows, T. T.; Tims, S. G.

    2007-06-01

    The cosmogenic isotope 53Mn is produced by spallation of iron in surface rocks. The long half life of this isotope makes it attractive for use in erosion rate studies in slowly eroding landscapes such as Australia. We describe the development of AMS methods for detection of 53Mn using the 14UD accelerator at the Australian National University. The first step of this development involved the production of 53Mn using a heavy-ion fusion-evaporation reaction to make test standards. Then, the chemistry protocol for isolating 53Mn and reducing the Cr levels, of which 53Cr is a serious interfering isobar, was developed. Lastly we employed a gas-filled magnet which was used to discriminate 53Mn from the intense 53Cr background.

  11. Manganese-53: Development of the AMS technique for exposure-age dating applications

    Energy Technology Data Exchange (ETDEWEB)

    Gladkis, L.G. [Department of Nuclear Physics, Research School of Physical Sciences and Engineering, Australian National University, Canberra ACT 0200 (Australia); Fifield, L.K. [Department of Nuclear Physics, Research School of Physical Sciences and Engineering, Australian National University, Canberra ACT 0200 (Australia); Morton, C.R. [Department of Nuclear Physics, Research School of Physical Sciences and Engineering, Australian National University, Canberra ACT 0200 (Australia)]. E-mail: clyde.morton@anu.edu.au; Barrows, T.T. [Department of Nuclear Physics, Research School of Physical Sciences and Engineering, Australian National University, Canberra ACT 0200 (Australia); Tims, S.G. [Department of Nuclear Physics, Research School of Physical Sciences and Engineering, Australian National University, Canberra ACT 0200 (Australia)

    2007-06-15

    The cosmogenic isotope {sup 53}Mn is produced by spallation of iron in surface rocks. The long half life of this isotope makes it attractive for use in erosion rate studies in slowly eroding landscapes such as Australia. We describe the development of AMS methods for detection of {sup 53}Mn using the 14UD accelerator at the Australian National University. The first step of this development involved the production of {sup 53}Mn using a heavy-ion fusion-evaporation reaction to make test standards. Then, the chemistry protocol for isolating {sup 53}Mn and reducing the Cr levels, of which {sup 53}Cr is a serious interfering isobar, was developed. Lastly we employed a gas-filled magnet which was used to discriminate {sup 53}Mn from the intense {sup 53}Cr background.

  12. Concepts of probability in radiocarbon analysis

    Directory of Open Access Journals (Sweden)

    Bernhard Weninger

    2011-12-01

    Full Text Available In this paper we explore the meaning of the word probability, not in general terms, but restricted to the field of radiocarbon dating, where it has the meaning of ‘dating probability assigned to calibrated 14C-ages’. The intention of our study is to improve our understanding of certain properties of radiocarbon dates, which – although mathematically abstract – are fundamental both for the construction of age models in prehistoric archaeology, as well as for an adequate interpretation of their reliability.

  13. Radiocarbon intercomparison program for Chauvet Cave

    NARCIS (Netherlands)

    Cuzange, Marie-Therese; Delque-Kolic, Emmanuelle; Goslar, Tomasz; Grootes, Pieter Meiert; Higham, Tom; Kaltnecker, Evelyne; Nadeau, Marie-Josee; Oberlin, Christine; Paterne, Martine; van der Plicht, Johannes; Ramsey, Christopher Bronk; Valladas, Helene; Clottes, Jean; Geneste, Jean-Michel

    2007-01-01

    We present the first results of an accelerator mass spectrometry (AMS) radiocarbon intercomparison program on 3 different charcoal samples collected in one of the hearths of the Megaceros gallery of Chauvet Cave (Ardeche, France). This cave, rich in parietal decoration, is important for the study of

  14. Intercomparison of radiocarbon bomb pulse and {sup 210}Pb age models. A study in a peat bog core from North Poland

    Energy Technology Data Exchange (ETDEWEB)

    Piotrowska, Natalia, E-mail: natalia.piotrowska@polsl.p [Department of Radioisotopes, Institute of Physics, Silesian University of Technology, Krzywoustego, 2, Gliwice 44100 (Poland); Vleeschouwer, Francois De; Sikorski, Jaroslaw; Pawlyta, Jacek [Department of Radioisotopes, Institute of Physics, Silesian University of Technology, Krzywoustego, 2, Gliwice 44100 (Poland); Fagel, Nathalie; Roux, Gael Le [Clays and Palaeoclimate Unit, Department of Geology, University of Liege, Allee du 6 Aout, B18, Sart Tilman, Liege 4000 (Belgium); Pazdur, Anna [Department of Radioisotopes, Institute of Physics, Silesian University of Technology, Krzywoustego, 2, Gliwice 44100 (Poland)

    2010-04-15

    Radiocarbon and {sup 210}Pb were measured on the uppermost 40 cm of a Wardenaar peat core retrieved from a Baltic raised bog at Slowinskie Blota (Pomerania, North Poland). This site is the subject of ongoing multiproxy studies covering the last 1300 years. Radiocarbon age model was constructed on the basis of 14 AMS dates obtained on selected Sphagnum spp. fragments, with use of P{sub S}equence tool. We present here a comparison of this model with the age model obtained using CRS model classically applied to {sup 210}Pb measurements.

  15. Radiocarbon application in dating 'complex' hot and cold CO{sub 2}-rich mineral water systems: A review of case studies ascribed to the northern Portugal

    Energy Technology Data Exchange (ETDEWEB)

    Carreira, Paula M. [Instituto Tecnologico e Nuclear, Departamento de Quimica, Estrada Nacional No 10, 2686-953 Sacavem (Portugal)], E-mail: carreira@itn.pt; Marques, Jose M.; Graca, Rui C.; Aires-Barros, Luis [Instituto Superior Tecnico, Laboratorio de Mineralogia e Petrologia, Av. Rovisco Pais, 1049-001 Lisboa (Portugal)

    2008-10-15

    The use of radioactive isotopes plays a very important role in dating groundwater, providing an apparent age of the systems in the framework of the aquifers conceptual modelling making available important features about the water fluxes, such as recharge, horizontal flow rates and discharge. In this paper, special emphasis has been put on isotopic constraints in the use of {delta}{sup 13}C and {sup 14}C content as a dating tool in some hot (76 deg. C) and cold (17 deg. C) CO{sub 2}-rich mineral waters discharging in the Vilarelho da Raia-Pedras Salgadas region (N-Portugal). The radiocarbon content determined in these CO{sub 2}-rich mineral waters ({sup 14}C activity from 4.3 up to 9.9 pmc) is incompatible with the systematic presence of {sup 3}H (from 1.7 to 7.9 TU). The {delta}{sup 13}C values of the studied CO{sub 2}-rich mineral waters indicate that the total C in the recharge waters is being masked by larger quantities of CO{sub 2} ({sup 14}C-free) introduced from deep-seated (upper mantle) sources. This paper demonstrates that a good knowledge of mineral water systems is essential to allow hydrologists to make sound conclusions on the use of C isotopic data in each particular situation.

  16. Status report of AMS sample preparation laboratory at GADAM Centre, Gliwice, Poland

    Energy Technology Data Exchange (ETDEWEB)

    Piotrowska, N., E-mail: natalia.piotrowska@polsl.pl [GADAM Centre of Excellence, Department of Radioisotopes, Institute of Physics, Silesian University of Technology, Gliwice (Poland)

    2013-01-15

    The laboratory for {sup 14}C AMS sample preparation in the Gliwice Radiocarbon Laboratory has gradually evolved since its start in 1999 to cater for an increase in volume and variety of radiocarbon dating samples. To date, nearly 2000 graphite targets have been produced from materials such as plant macrofossils, charcoal, peat, bones, shells and wood. The equipment comprises a station for chemical preparation and high vacuum lines for production, purification and graphitization of sample carbon dioxide. The present capacity allows preparation of up to 400 targets annually for the needs of scientific projects and external orders for radiocarbon dating continuously received by the GADAM Centre of Excellence. The laboratory's sample preparation protocols and recent improvements are described and its performance during the 10 years of activity is discussed in terms of parameters obtained from reference materials prepared in this laboratory and demonstrated with a few science applications.

  17. Strategy of valid 14C dates choice in syngenetic permafrost

    Directory of Open Access Journals (Sweden)

    Y. K. Vasil'chuk

    2014-11-01

    Full Text Available The main problem of radiocarbon dating within permafrost is the uncertain reliability of the 14C dates. Syngenetic sediments contain allochthonous organic deposit that originated at a distance from its present position. Due to the very good preservation of organic materials in permafrost conditions and numerous re-burials of the fossils from ancient deposits into younger ones the dates could be both younger and older than the true age of dated material. The strategy for the most authentic radiocarbon date selection for dating of syncryogenic sediments is considered taking into account the fluvial origin of the syngenetic sediments. The re-deposition of organic material is discussed in terms of cyclic syncryogenic sedimentation and also the possible re-deposition of organic material in subaerial-subaqueous conditions. The advantages and the complications of dating organic micro-inclusions from ice wedges by the accelerator mass spectrometry (AMS method are discussed applying to true age of dated material search. Radiocarbon dates of different organic materials from the same samples are compared. The younger age of the yedoma from cross-sections of Duvanny Yar in Kolyma River and Mamontova Khayata in the mouth of Lena River is substantiated due to the principle of the choice of the youngest 14C date from the set.

  18. The AMS {sup 14}C dating of Iron Age rice chaff ceramic temper from Ban Non Wat, Thailand: First results and its interpretation

    Energy Technology Data Exchange (ETDEWEB)

    Higham, Charles F.W., E-mail: charles.higham@otago.ac.n [Department of Anthropology, Otago University, Dunedin (New Zealand); Kuzmin, Yaroslav V. [Institute of Geology and Mineralogy, Siberian Branch of the Russian Academy of Sciences, Koptuyg Ave. 3, Novosibirsk 630090 (Russian Federation); Burr, G.S. [Arizona AMS Laboratory, University of Arizona, Tucson, AZ 85721 0081 (United States)

    2010-04-15

    Pottery tempered with rice chaff from the early Iron Age cemetery of Ban Non Wat site, northeast Thailand, has been subjected to direct AMS {sup 14}C dating, using low temperature combustion with oxygen as originally developed by authors. The carbon yield (0.2-0.5%) testifies the suitability of this pottery for dating. However, not all the results are in agreement with expected archaeological ages and other {sup 14}C dates from the studied site and neighboring site of Noen U-Loke. This calls for a thorough analysis and interpretation of pottery temper dates from the region.

  19. Applications of radiocarbon measurements in environmental studies at INFN-LABEC, Florence

    Directory of Open Access Journals (Sweden)

    Chiari M.

    2012-04-01

    Full Text Available Radiocarbon is one of the most widespread radionuclides in nature. Although it is probably best known for dating in archaeology, in the case of the general public, it represents a useful tracer to study our environment, both in the past and nowadays. For instance, carbonaceous particles, which are in many cases the most abundant among aerosols constituents, are believed to play a major role in both health and climatic effects of aerosols. In particular, measurement of radiocarbon concentration in particulate matter samples can give information on the contributions of the fossil fuels combustion and of natural sources to the carbonaceous fraction in aerosols. These measurements are especially effective when separately performed on different carbonaceous fractions, like elemental and organic carbon (EC and OC, respectively. Past climate is also studied thanks to old archives, as e.g. marine sediments can be. In this case, instead of radiocarbon dating the bulk sediment, a reliable method to fix chronological markers is represented by dating foraminifera tests of CaCO3 picked from different layers in the sediment. Both the aforementioned applications are characterized by the fact that the samples that can be collected for 14C measurements are typically very small, i.e. few mg or less (before any treatment. Accelerator Mass Spectrometry (AMS is thus the only technique that can be applied to measure radiocarbon in such samples. Anyway, measurements cannot be so straightforward. In the case of the measurement of radiocarbon concentration in aerosol samples, a preparation line especially dedicated to the extraction of only the carbonaceous fraction of interest is mandatory. Actually, this line should include a combustion oven, from which either total carbon or EC and OC can separately evolve, and a system of traps to purify and collect the CO2. In the case of foraminifera tests (inorganic carbon, special care must be taken in the pre-treatment phase

  20. Changes in solar activity and Holocene climatic shifts derived from 14C wiggle-match dated peat deposits

    NARCIS (Netherlands)

    Mauquoy, Dmitri; Geel, Bas van; Blaauw, Maarten; Speranza, Alessandra; Plicht, Johannes van der

    2004-01-01

    Closely spaced sequences of accelerator mass spectrometer (AMS) 14C dates of peat deposits display century-scale wiggles which can be fitted to the radiocarbon calibration curve. By wiggle-matching such sequences, high-precision calendar age chronologies can be generated which show that changes in m

  1. AMS-dated mollusks in beach ridges and berms document Holocene sea-level and coastal changes in northeastern Kuwait Bay

    Science.gov (United States)

    Reinink-Smith, Linda M.

    2015-09-01

    In northeastern Kuwait, ancient beach ridges and associated berms are separated from the present shoreline by a 4-6 km-wide sabkha. A diverse mollusk fauna in the beach ridges attests to a former open marine environment. A total of 21 AMS dates were obtained in this study. Thirteen mollusk samples from beach ridges yielded AMS dates ranging from ~ 6990 cal yr BP in the southeast to ~ 3370 cal yr BP in the northwest, suggesting a southeast to northwest age progression during the Holocene transgression. In contrast, four samples from berms throughout the study area yielded AMS dates of 5195-3350 cal yr BP showing no age progression; these berms consist largely of Conomurex persicus gastropods that aggregated by storms during a highstand at ~ 5000-3500 cal yr BP. The berms are presently at ~ + 6 m above sea level, 2-3 m above the beach ridges. Human settlements were common on the ridge crests before and after the highstand. Regression to present-day sea level commenced after the highstand, which is when the sabkha began forming. A landward, marine-built terrace, which yielded AMS dates > 43,500 14C yr BP, probably formed during Marine Oxygen Isotope Stage 5e and hence is not genetically related to the beach ridges.

  2. Extraneous carbon assessment in ultra-microscale radiocarbon analysis using benzene polycarboxylic acids (BPCA)

    Science.gov (United States)

    Hanke, Ulrich M.; McIntyre, Cameron P.; Schmidt, Michael W. I.; Wacker, Lukas; Eglinton, Timothy I.

    2016-04-01

    Measurements of the natural abundance of radiocarbon (14C) concentrations in inorganic and organic carbon-containing materials can be used to investigate their date of origin. Particularly, the biogeochemical cycling of specific compounds in the environment may be investigated applying molecular marker analyses. However, the isolation of specific molecules from environmental matrices requires a complex processing procedure resulting in small sample sizes that often contain less than 30 μg C. Such small samples are sensitive to extraneous carbon (Cex) that is introduced during the purification of the compounds (Shah and Pearson, 2007). We present a thorough radiocarbon blank assessment for benzene polycarboxylic acids (BPCA), a proxy for combustion products that are formed during the oxidative degradation of condensed polyaromatic structures (Wiedemeier et al, in press). The extraneous carbon assessment includes reference material for (1) chemical extraction, (2) preparative liquid chromatography (3) wet chemical oxidation which are subsequently measured with gas ion source AMS (Accelerator Mass Spectrometer, 5-100 μg C). We always use pairs of reference materials, radiocarbon depleted (14Cfossil) and modern (14Cmodern) to determine the fraction modern (F14C) of Cex.Our results include detailed information about the quantification of Cex in radiocarbon molecular marker analysis using BPCA. Error propagation calculations indicate that ultra-microscale samples (20-30 μg) are feasible with uncertainties of less than 10 %. Calculations of the constant contamination reveal important information about the source (F14C) and mass (μg) of Cex (Wacker and Christl, 2011) for each sub procedure. An external correction of compound specific radiocarbon data is essential for robust results that allow for a high degree of confidence in the 14C results. References Shah and Pearson, 2007. Ultra-microscale (5-25μg C) analysis of individual lipids by 14C AMS: Assessment and

  3. Dating Cactus: Annual and Sub-annual Variations of Oxygen-18, Carbon-13 and Radiocarbon in Spines of a Columnar Cactus, Carnegiea gigantea.

    Science.gov (United States)

    Dettman, D. L.; English, N. B.; Sandquist, D. R.; Williams, D. G.

    2006-12-01

    We measured δ18O, δ13C and F14C of spines from a long-lived columnar cactus, Carnegiea gigantea (saguaro), to resolve a record of plant physiological responses to annual and sub-annual climate variation in the eastern Sonoran Desert. Spines grow from the apex of the cactus and are arranged serially along the side of the cactus oldest at the base, youngest at the apex. To establish the age of the spine series, we measured F14C of spines collected at 8 different heights from the apex (3.77 m) to the base of a naturally occurring saguaro. These spines yielded fractions of modern carbon (F14C) from 0.9679 and 1.5537, indicating the presence of carbon in spine tissue derived from atmospheric nuclear testing. We used the F14C of spine tissue to calculate the year of spine emergence for each of the 11 spines, assuming minimal re-allocation of stored carbon to growing spines. At the same 8 heights, we interpolated the date of spine emergence from observed height measurements made between 1964 and 2002. A very strong positive correlation (linear regression, r2 = 0.99, P spines and ages determined from direct height measurements was observed, with a two year offset suggesting incorporation of carbon from fossil fuel combustion sources in the Tucson basin. Additionally, spine tips from 97 spines collected serially from the top half of the same saguaro (between 1.77 and 3.50 m) and representing ~15 years of growth, yielded δ18O variations in spine bulk organic material from 38° to 50° (VSMOW) and in δ13C from ° to 11.5° (VPDB). The δ18O and δ13C values were positively correlated over the entire record (linear regression, r2 = 0.22, P spine organic material from the naturally occurring cactus were observed in spines grown shortly following the 1983 and 1993 strong El Niño winter precipitation events in Tucson, suggesting that isotopes in spine tissue are a good proxy of these climate anomalies. We found similar δ18O, δ13C and F14C variations and relationships in a

  4. A decade of AMS at the University of Georgia

    Science.gov (United States)

    Culp, Randy; Noakes, John; Cherkinsky, Alex; Ravi Prasad, G. V.; Dvoracek, Doug

    2013-01-01

    In a span of 10 years, the University of Georgia’s Center for Applied Isotope Studies (CAIS) has transformed itself from principally a liquid scintillation counting (LSC) laboratory to one conducting thousands of accelerator mass spectrometry (AMS) and stable isotope ratio analysis (SIRA) annually. After receiving the first of the NEC compact AMS units in the United States, the CAIS began to meet the demand for 14C analysis outside the normal realm of most radiocarbon dating laboratories. With industry’s support, isotope research continued on an already developing natural products program to authenticate materials origin and process of formation. The CAIS’s AMS allowed for the detection of synthetic materials in milligram quantities rather than gram quantities required by LSC and allowed new compound specific SIRA techniques to be directed toward compound specific 14C measurement. By 2005 the CAIS was one of only a few laboratories accredited to determine bio-base content in industrial fuels and products by both AMS and LSC following ASTM D6866-10 [1]. Since 2001, when our first sample was analyzed by AMS method, both radiocarbon and natural products sample numbers have increased steadily. The advantages of AMS analysis in overall efficiency, cost savings, accuracy, and precision, are detailed here in a review of analytical precision for radiocarbon and natural products analyzed over 10 years of AMS operation. Comparisons are made between natural products and bio-based materials analyzed by both AMS and LSC. Although high precision is not required to authenticate natural products, for the purpose of product comparison with regard to degree of naturalness accurate and precise 14C measurement is shown to be achievable by both methods.

  5. A decade of AMS at University of Georgia

    Energy Technology Data Exchange (ETDEWEB)

    Culp, Randy, E-mail: rculp@uga.edu [Center for Applied Isotope Studies, University of Georgia, Athens, GA (United States); Noakes, John; Cherkinsky, Alex; Ravi Prasad, G.V.; Dvoracek, Doug [Center for Applied Isotope Studies, University of Georgia, Athens, GA (United States)

    2013-01-15

    In a span of 10 years, University of Georgia's Center for Applied Isotope Studies (CAIS) has transformed itself from principally a liquid scintillation counting (LSC) laboratory to one conducting thousands of accelerator mass spectrometry (AMS) and stable isotope ratio analysis (SIRA) annually. After receiving the first of the NEC compact AMS units in the United States, the CAIS began to meet the demand for {sup 14}C analysis outside the normal realm of most radiocarbon dating laboratories. With industry's support, isotope research continued on an already developing natural products program to authenticate materials origin and process of formation. The CAIS's AMS allowed for the detection of synthetic materials in milligram quantities rather than gram quantities required by LSC and allowed new compound specific SIRA techniques to be directed toward compound specific {sup 14}C measurement. By 2005 the CAIS was one of only a few laboratories accredited to determine bio-base content in industrial fuels and products by both AMS and LSC following ASTM D6866-10 [1]. Since 2001, when our first sample was analyzed by AMS method, both radiocarbon and natural products sample numbers have increased steadily. The advantages of AMS analysis in overall efficiency, cost savings, accuracy, and precision, are detailed here in a review of analytical precision for radiocarbon and natural products analyzed over 10 years of AMS operation. Comparisons are made between natural products and bio-based materials analyzed by both AMS and LSC. Although high precision is not required to authenticate natural products, for the purpose of product comparison with regard to degree of naturalness accurate and precise {sup 14}C measurement is shown to be achievable by both methods.

  6. Radiocarbon positive-ion mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Freeman, Stewart P.H.T.; Shanks, Richard P. [Scottish Universities Environmental Research Centre (SUERC), Scottish Enterprise Technology Park, East Kilbride G75 0QF (United Kingdom); Donzel, Xavier; Gaubert, Gabriel [Pantechnik S.A., 13 Rue de la Résistance, 14400 Bayeux (France)

    2015-10-15

    Proof-of-principle of a new mass spectrometric technique for radiocarbon measurement is demonstrated. Interfering nitrogen and hydrocarbon molecules are largely eliminated in a charge-exchange cell operating on non-metallic gas. The positive-to-negative ion conversion is the reverse of that conventionally used in accelerator mass spectrometry (AMS) and is compatible with plasma ion sources that may be significantly more efficient and capable of greater output than are AMS sputter ion sources. The Nanogan electron cyclotron resonance (ECR) ion source employed exhibited no sample memory and the >50 kyrs age range of AMS was reproduced. A bespoke prototype new instrument is now required to optimise the plasma and cell physics and to realise hypothetical performance gains over AMS.

  7. AMS-14C Dating of the Holocene Loess Sequence at Lantian, Shaanxi and Reflected Environmental Change%陕西蓝田全新世黄土AMS-14C测年与环境变迁

    Institute of Scientific and Technical Information of China (English)

    张婷; 祝一志; 杨亚长; 邵晶

    2011-01-01

    AMS-14C dating provides a new way in archaeology studies because of its high precision and speed and applicability in micro-sample dating. It is widely used in late Quaternary and Neolithic archaeological research. Based on AMS-14C dating of loess-paleosol sequence of the Xinjie profile at Lantian County of Shaanxi Province, the archaeological chronology of this sequence was obtained by using Bayesian method. Combining the stratigraphic sequence, magnetic susceptibility and pollen analysis, we got the conclusion that the weather was dry and cold during Malan loess period, and warm in Holocene, humid and warm in Yangshao period, dry and warm in Longshan period, dry and cold in recent Loess forming period.%加速器质谱计14C(AMS-14C)测年技术具有精度高、速度快以及样品需求量少的特点,已广泛用于晚第四纪和新石器时期的断代研究.通过对蓝田县新街遗址旁的全新世黄土-古土壤序列进行AMS-14C测年,并利用贝叶斯分析方法,建立了该地层序列的年代学框架.结合新街遗址考察、黄土-古土壤地层划分、磁化率测量和孢粉分析,表明马兰黄土晚期气候偏凉干,进入全新世时期气候转暖,仰韶时期温暖湿润,龙山时期气候暖偏于,新黄土堆积时期气候转于冷.

  8. Estimation of paleotemperature from racemization of aspartic acid in combination with radiocarbon age

    Science.gov (United States)

    Minami, Masayo; Takeyama, Masami; Mimura, Koichi; Nakamura, Toshio

    2007-06-01

    We tried to estimate paleotemperatures from two chosen fossils by measuring D/L aspartic acid ratios and radiocarbon ages of the XAD-2-treated hydrolysate fractions in the fossils. The D/L aspartic acid ratio was measured with a gas chromatograph and radiocarbon dating was performed using a Tandetron AMS system at Nagoya University. The radiocarbon age of a fossil mammoth molar collected from Bykovsky Peninsula, eastern Siberia, was found to be 35,170 ± 300 BP as an average value for the XAD-treated hydrolysate fractions. The aspartic acid in the mammoth molar showed a little evidence of racemization, which might be due to in vivo racemization during the lifetime and then suggests negligible or no postmortem racemization during burial in permafrost. From four animal bone fossils collected from a shell mound excavated at the Awazu submarine archeological site in Lake Biwa, Shiga, Japan, the racemization-based effective mean temperature was calculated to be 15-16 °C using the D/L aspartic acid ratio of about 0.11 and the 14C age of 4500 BP for the XAD-2-treated hydrolysate fractions in the fossils. The average annual temperature was estimated to be 11-12 °C, which approximates to the temperature that the fossils experienced during burial at the site. Although the application of racemization ratios in fossils as paleotemperature indicators is surrounded with many difficulties, the results obtained in this study suggest its feasibility.

  9. Estimation of paleotemperature from racemization of aspartic acid in combination with radiocarbon age

    Energy Technology Data Exchange (ETDEWEB)

    Minami, Masayo [Center for Chronological Research, Nagoya University, Nagoya 464-8602 (Japan)]. E-mail: minami@nendai.nagoya-u.ac.jp; Takeyama, Masami [Department of Earth and Planetary Sciences, School of Science, Nagoya 464-8602 (Japan); Mimura, Koichi [Graduate School of Environmental Studies, Nagoya University, Nagoya 464-8602 (Japan); Nakamura, Toshio [Center for Chronological Research, Nagoya University, Nagoya 464-8602 (Japan)

    2007-06-15

    We tried to estimate paleotemperatures from two chosen fossils by measuring D/L aspartic acid ratios and radiocarbon ages of the XAD-2-treated hydrolysate fractions in the fossils. The D/L aspartic acid ratio was measured with a gas chromatograph and radiocarbon dating was performed using a Tandetron AMS system at Nagoya University. The radiocarbon age of a fossil mammoth molar collected from Bykovsky Peninsula, eastern Siberia, was found to be 35,170 {+-} 300 BP as an average value for the XAD-treated hydrolysate fractions. The aspartic acid in the mammoth molar showed a little evidence of racemization, which might be due to in vivo racemization during the lifetime and then suggests negligible or no postmortem racemization during burial in permafrost. From four animal bone fossils collected from a shell mound excavated at the Awazu submarine archeological site in Lake Biwa, Shiga, Japan, the racemization-based effective mean temperature was calculated to be 15-16 deg. C using the D/L aspartic acid ratio of about 0.11 and the {sup 14}C age of 4500 BP for the XAD-2-treated hydrolysate fractions in the fossils. The average annual temperature was estimated to be 11-12 deg. C, which approximates to the temperature that the fossils experienced during burial at the site. Although the application of racemization ratios in fossils as paleotemperature indicators is surrounded with many difficulties, the results obtained in this study suggest its feasibility.

  10. ESR and AMS-based 14C Dating of Mousterian Levels at Mujina Pećina, Dalmatia, Croatia

    NARCIS (Netherlands)

    Rink, W.J.; Karavanić, I.; Pettitt, P.B.; Plicht, J. van der; Smith, F.H.; Bartoll, J.; Karavanic, I.

    2002-01-01

    This paper presents the first chronometric dates for sediments that contain a Mousterian industry in Dalmatia (south Croatia). Electron spin resonance (ESR) dating was conducted on two teeth from the Mousterian level E1 at the site of Mujina Pećina. Additionally five bone and one charcoal sample fro

  11. AMS and controversies in history The Spanish conquest of Peru

    CERN Document Server

    Zoppi, U; Jacobsen, G; Laurencich-Minelli, L; Lawson, E M; Sarkisian, G; Tuniz, C

    2000-01-01

    The quest for understanding the past often contains a subjective component. Legends, myths, traditions and personal beliefs can unconsciously influence the interpretation of the scientific outcomes or, in the worst instances, even lead to forgery. Fortunately, an increasing number of scientific tools are available nowadays and can be combined to discredit such detriments and offer more reliable foundations for an objective analysis. Radiocarbon dating by AMS is a relatively non-invasive method and is particularly useful when valuable historical artefacts are involved. In this paper, we will present controversial cases where AMS is playing an important role in understanding the past. In particular, we will discuss the use of AMS to authenticate historical documents revealing a new version of the conquest of Peru by Pizarro in the early 1530s.

  12. In situ determination of /sup 241/Am on Enewetak Atoll. Date of survey: July 1977-December 1979

    Energy Technology Data Exchange (ETDEWEB)

    Tipton, W.J.; Fritzsche, A.E.; Jaffe, R.J.; Villaire, A.E.

    1981-11-01

    An in situ gamma ray spectrometer system was operated at Enewetak Atoll from July 1977 to December 1979 in support of the Enewetak Cleanup Project. The system employed a high purity germanium planar detector suspended at a height of 7.4 m above ground. Conversion factors were established to relate measured photopeak count rate data to source concentration in the soil. Data obtained for /sup 241/Am, together with plutonium-to-americium ratios obtained from soil sample analyses, were used to establish area-averaged surface (0 to 3 cm) transuranic concentration values. In areas which exceeded cleanup criteria, measurements were made in an iterative fashion to guide soil removal until levels were reduced below the cleanup criteria. Final measurements made after soil removal had been completed were used to document remaining surface transuranic concentration values and to establish external exposure rate levels due to /sup 137/Cs and /sup 60/Co.

  13. Comment on "Radiocarbon Calibration Curve Spanning 0 to 50,000 Years B.P. Based on Paired 230Th/234U/238U and 14C Dates on Pristine Corals" by R.G. Fairbanks, R. A. Mortlock, T.-C. Chiu, L. Cao, A. Kaplan, T. P. Guilderson, T. W. Fairbanks, A. L. Bloom, P

    Energy Technology Data Exchange (ETDEWEB)

    Reimer, P J; Baillie, M L; Bard, E; Beck, J W; Blackwell, P G; Buck, C E; Burr, G S; Edwards, R L; Friedrich, M; Guilderson, T P; Hogg, A G; Hughen, K A; Kromer, B; McCormac, G; Manning, S; Reimer, R W; Southon, J R; Stuiver, M; der Plicht, J v; Weyhenmeyer, C E

    2005-10-02

    Radiocarbon calibration curves are essential for converting radiocarbon dated chronologies to the calendar timescale. Prior to the 1980's numerous differently derived calibration curves based on radiocarbon ages of known age material were in use, resulting in ''apples and oranges'' comparisons between various records (Klein et al., 1982), further complicated by until then unappreciated inter-laboratory variations (International Study Group, 1982). The solution was to produce an internationally-agreed calibration curve based on carefully screened data with updates at 4-6 year intervals (Klein et al., 1982; Stuiver and Reimer, 1986; Stuiver and Reimer, 1993; Stuiver et al., 1998). The IntCal working group has continued this tradition with the active participation of researchers who produced the records that were considered for incorporation into the current, internationally-ratified calibration curves, IntCal04, SHCal04, and Marine04, for Northern Hemisphere terrestrial, Southern Hemisphere terrestrial, and marine samples, respectively (Reimer et al., 2004; Hughen et al., 2004; McCormac et al., 2004). Fairbanks et al. (2005), accompanied by a more technical paper, Chiu et al. (2005), and an introductory comment, Adkins (2005), recently published a ''calibration curve spanning 0-50,000 years''. Fairbanks et al. (2005) and Chiu et al. (2005) have made a significant contribution to the database on which the IntCal04 and Marine04 calibration curves are based. These authors have now taken the further step to derive their own radiocarbon calibration extending to 50,000 cal BP, which they claim is superior to that generated by the IntCal working group. In their papers, these authors are strongly critical of the IntCal calibration efforts for what they claim to be inadequate screening and sample pretreatment methods. While these criticisms may ultimately be helpful in identifying a better set of protocols, we feel that there are

  14. Impact of fossil fuel emissions on atmospheric radiocarbon and various applications of radiocarbon over this century.

    Science.gov (United States)

    Graven, Heather D

    2015-08-04

    Radiocarbon analyses are commonly used in a broad range of fields, including earth science, archaeology, forgery detection, isotope forensics, and physiology. Many applications are sensitive to the radiocarbon ((14)C) content of atmospheric CO2, which has varied since 1890 as a result of nuclear weapons testing, fossil fuel emissions, and CO2 cycling between atmospheric, oceanic, and terrestrial carbon reservoirs. Over this century, the ratio (14)C/C in atmospheric CO2 (Δ(14)CO2) will be determined by the amount of fossil fuel combustion, which decreases Δ(14)CO2 because fossil fuels have lost all (14)C from radioactive decay. Simulations of Δ(14)CO2 using the emission scenarios from the Intergovernmental Panel on Climate Change Fifth Assessment Report, the Representative Concentration Pathways, indicate that ambitious emission reductions could sustain Δ(14)CO2 near the preindustrial level of 0‰ through 2100, whereas "business-as-usual" emissions will reduce Δ(14)CO2 to -250‰, equivalent to the depletion expected from over 2,000 y of radioactive decay. Given current emissions trends, fossil fuel emission-driven artificial "aging" of the atmosphere is likely to occur much faster and with a larger magnitude than previously expected. This finding has strong and as yet unrecognized implications for many applications of radiocarbon in various fields, and it implies that radiocarbon dating may no longer provide definitive ages for samples up to 2,000 y old.

  15. In search of in-situ radiocarbon in Law Dome ice and firn

    CERN Document Server

    Smith, A M; Etheridge, D M; Lowe, D C; Hua, Q; Trudinger, C M; Zoppi, U; El-Cheikh, A

    2000-01-01

    Results of AMS radiocarbon measurements on CO and CO sub 2 separated from firn air directly pumped from the ice sheet, and on CO sub 2 separated from air extracted from ice cores by a dry grating technique, are presented. The firn air samples and ice cores used in this study were collected from the region of Law Dome, Antarctica. No evidence of in-situ sup 1 sup 4 CO sub 2 was found in the firn air samples or the ice core air samples from one site although a slight enhancement of sup 1 sup 4 CO above expected polar atmospheric concentrations was observed for some firn air samples. A clear in-situ sup 1 sup 4 CO sub 2 signal for ice pre-dating the radiocarbon bomb pulse was found, however, in air samples extracted from an ice core from a second site. We compare these results and propose an hypothesis to explain this apparent contradiction. The degree to which in-situ sup 1 sup 4 C is released from the ice crystals during trapping and bubble formation is considered and discussed. The selectivity of the dry grat...

  16. Radiocarbon application in environmental science and archaeology in Croatia

    Energy Technology Data Exchange (ETDEWEB)

    Krajcar Bronic, I., E-mail: krajcar@irb.h [Radiocarbon Laboratory, Department of Experimental Physics, Ruder Boskovic Institute, Bijenicka 54, 10000 Zagreb (Croatia); Obelic, B.; Horvatincic, N.; Baresic, J.; Sironic, A. [Radiocarbon Laboratory, Department of Experimental Physics, Ruder Boskovic Institute, Bijenicka 54, 10000 Zagreb (Croatia); Minichreiter, K. [Institute of Archaeology, Ulica grada Vukovara 68, 10000 Zagreb (Croatia)

    2010-07-21

    Radiocarbon is a cosmogenic radioisotope equally distributed throughout the troposphere and biosphere. This fact enables its most common application-radiocarbon dating. Natural equilibrium of radiocarbon has been disturbed by diverse anthropogenic activities during the last {approx}150 years, enabling also the use of {sup 14}C in various environmental applications. Here we present three types of studies by using {sup 14}C that were performed in the Zagreb Radiocarbon Laboratory. {sup 14}C in atmospheric CO{sub 2} has been monitored at several sites with various anthropogenic influences and the difference between the clean-air sites, the industrial city and the vicinity of a nuclear power plant has been established. {sup 14}C has been applied in geochronology of karst areas, especially in dating of tufa, speleothems and lake sediments, as well as in studies of geochemical carbon cycle. {sup 14}C has been used in various archaeological studies, among which the dating of the early Neolithic settlements in Croatia is presented. In these studies {sup 14}C was measured by radiometric techniques, i.e., by gas proportional counting and more recently by liquid scintillation counting (LSC). Two sample preparation techniques for LSC measurement were used: benzene synthesis for archaeological dating and other applications that require better precision, and direct absorption of CO{sub 2} for monitoring purposes. The presented results show that various studies by using {sup 14}C can be successfully performed by the LSC technique, providing a large enough sample (>1 g of carbon).

  17. PROGRESS AT THE GRONINGEN AMS FACILITY

    NARCIS (Netherlands)

    MOUS, DJW; GOTTDANG, A; VANDERPLICHT, J; WIJMA, S; ZONDERVAN, A

    1995-01-01

    A new generation accelerator mass spectrometer (AMS) is operational since May 1994 at the Centre for Isotope Research in Groningen, The Netherlands. The fully automated and high throughput AMS system, manufactured by High Voltage Engineering Europa (HVEE) is dedicated to radiocarbon analysis. The mo

  18. New radiocarbon data to study the history of roman and medieval Florence

    Energy Technology Data Exchange (ETDEWEB)

    Arnoldus-Huyzendveld, A. [Dipartimento di Archeologia e Storia delle Arti, Universita di Siena, via Roma 56, 53100 Siena (Italy); Fedi, M.E., E-mail: fedi@fi.infn.i [INFN Sezione di Firenze, via Sansone 1, 50019 Sesto Fiorentino (Italy); Cantini, F.; Bruttini, J. [Dipartimento di Archeologia e Storia delle Arti, Universita di Siena, via Roma 56, 53100 Siena (Italy); Cartocci, A. [INFN Sezione di Firenze, via Sansone 1, 50019 Sesto Fiorentino (Italy); Dipartimento di Fisica dell' Universita di Firenze, via Sansone 1, 50019 Sesto Fiorentino (Italy); Calabrisotto, C. Scire [Dipartimento di Fisica dell' Universita di Firenze, via Sansone 1, 50019 Sesto Fiorentino (Italy)

    2010-04-15

    Florence is a town worldwide known for its Renaissance masterpieces. It is often forgotten that it was founded during Roman times and remained a small village until the end of the early Middle Ages, practically confined within the ancient Roman boundaries. Since 2003, an extended archaeological research executed by the University of Sienna has studied the most ancient layers in the centre of Florence with the aim to enhance both the archaeological and paleo-environmental reconstruction of this area. One of the peculiarities of these excavations is that the early medieval layers were poor in datable ceramics, thus charcoals were sampled from different stratigraphic layers in order to contribute to the dating. Several data have already been published; here we focus on the excavation site of Palazzo Vecchio, now the seat of the municipality of Florence. This area is located close to the Arno river, along the eastern margin of the slightly elevated height upon which the Roman town was founded; actually, in the layers beneath the surface, the Roman theatre is still preserved. Radiocarbon dating of charcoals was performed in the LABEC laboratory in Florence, at the AMS beam line of the AMS-IBA 3 MV Tandetron accelerator. Comparison of these new data with the former ones and with the archaeological and geological data adds new information especially on natural phenomena like floods and on the human occupation of this area in the past.

  19. New radiocarbon data to study the history of roman and medieval Florence

    Science.gov (United States)

    Arnoldus-Huyzendveld, A.; Fedi, M. E.; Cantini, F.; Bruttini, J.; Cartocci, A.; Calabrisotto, C. Scirè

    2010-04-01

    Florence is a town worldwide known for its Renaissance masterpieces. It is often forgotten that it was founded during Roman times and remained a small village until the end of the early Middle Ages, practically confined within the ancient Roman boundaries. Since 2003, an extended archaeological research executed by the University of Sienna has studied the most ancient layers in the centre of Florence with the aim to enhance both the archaeological and paleo-environmental reconstruction of this area. One of the peculiarities of these excavations is that the early medieval layers were poor in datable ceramics, thus charcoals were sampled from different stratigraphic layers in order to contribute to the dating. Several data have already been published; here we focus on the excavation site of Palazzo Vecchio, now the seat of the municipality of Florence. This area is located close to the Arno river, along the eastern margin of the slightly elevated height upon which the Roman town was founded; actually, in the layers beneath the surface, the Roman theatre is still preserved. Radiocarbon dating of charcoals was performed in the LABEC laboratory in Florence, at the AMS beam line of the AMS-IBA 3 MV Tandetron accelerator. Comparison of these new data with the former ones and with the archaeological and geological data adds new information especially on natural phenomena like floods and on the human occupation of this area in the past.

  20. A new system for the simultaneous measurement of δ{sup 13}C and δ{sup 15}N by IRMS and radiocarbon by AMS on gaseous samples: Design features and performances of the gas handling interface

    Energy Technology Data Exchange (ETDEWEB)

    Braione, Eugenia; Maruccio, Lucio; Quarta, Gianluca; D’Elia, Marisa; Calcagnile, Lucio, E-mail: lucio.calcagnile@unisalento.it

    2015-10-15

    We present the general design features and preliminary performances of a new system for the simultaneous AMS-{sup 14}C and IRMS δ{sup 13}C and δ{sup 15}N measurements on samples with masses in the μg range. The system consists of an elemental analyzer (EA), a gas splitting unit (GSU), a IRMS system, a gas handling interface (GHI) and a sputtering ion source capable of accepting gaseous samples. A detailed description of the system and of the control software supporting unattended operation are presented together with the first performance tests carried out by analyzing samples with masses ranging from 8 μgC to 2.4 mgC. The performances of the system were tested in term of stability of the ion beam extracted from the ion source, precision and accuracy of the results by comparing the measured isotopic ratios with those expected for reference materials.

  1. Tree rings and radiocarbon calibration

    Energy Technology Data Exchange (ETDEWEB)

    Barbetti, M. [University of Sydney, Sydney, NSW (Australia). NWG Macintosh Centre for Quaternary Dating

    1999-11-01

    Only a few kinds of trees in Australia and Southeast Asia are known to have growth rings that are both distinct and annual. Those that do are therefore extremely important to climatic and isotope studies. In western Tasmania, extensive work with Huon pine (Lagarostrobos franklinii) has shown that many living trees are more than 1,000 years old, and that their ring widths are sensitive to temperature, rainfall and cloud cover (Buckley et al. 1997). At the Stanley River there is a forest of living (and recently felled) trees which we have sampled and measured. There are also thousands of subfossil Huon pine logs, buried at depths less than 5 metres in an area of floodplain extending over a distance of more than a kilometre with a width of tens of metres. Some of these logs have been buried for 50,000 years or more, but most of them belong to the period between 15,000 years and the present. In previous expeditions in the 1980s and 1990s, we excavated and sampled about 350 logs (Barbetti et al. 1995; Nanson et al. 1995). By measuring the ring-width patterns, and matching them between logs and living trees, we have constructed a tree-ring dated chronology from 571 BC to AD 1992. We have also built a 4254-ring floating chronology (placed by radiocarbon at ca. 3580 to 7830 years ago), and an earlier 1268-ring chronology (ca. 7,580 to 8,850 years ago). There are many individuals, or pairs of logs which match and together span several centuries, at 9,000 years ago and beyond 15 refs., 1 tab., 1 fig.

  2. Youngest radiocarbon age for Jefferson's ground sloth, Megalonyx jeffersonii (Xenarthra, Megalonychidae)

    DEFF Research Database (Denmark)

    Gregory McDonald, H.; Stafford, Thomas W.; Gnidovec, Dale M.

    2015-01-01

    A partial skeleton of the extinct ground sloth, Megalonyx jeffersonii, recovered from a farm near Millersburg, Ohio in 1890, was radiocarbon dated for the first time. The ungual dated is part of a skeleton mounted for exhibit at the Orton Geological Museum at Ohio State University and was the first...... mounted skeleton of this animal. From its initial discovery the bones were treated with multiple organic compounds that had the potential to compromise the radiocarbon age and the specimen required special treatments in order to obtain a valid radiocarbon age. The 14C measurement on the ungual from...

  3. Dating of pollen samples from the sediment core of Lake St Anne in the East Carpathian Mountains, Romania

    Science.gov (United States)

    Hubay, Katalin; Katalin Magyari, Enikö; Braun, Mihály; Schabitz, Frank; Molnár, Mihály

    2016-04-01

    Lake St Anne (950 m a.s.l.) is situated in the Ciomadul volcano crater, the youngest volcano in the Carpathians. Aims driving forward the studies there are twofold, one is dating the latest eruption of the Ciomadul volcano and the other is the multi-proxy palaeoenvironmental reconstruction of this region. The sediment of Lake St Anne was sampled several times already, but never reached the bottom of the lake before. During the winter of 2013 at a new core location drilling started at 600 cm water depth and finally reached the bottom of the lake sediment at approximately 2300 cm including water depth. As for all multi-proxy studies essential requirement was to build a reliable chronology. Sediments were dated by radiocarbon method. Previous radiocarbon dates were measured on plant macrofossils, charcoal, Cladocera eggs, chironomid head capsules and bulk lake sediments. Lake St Anne has volcanic origin and there is intensive upwelling of CO2it is important to study and take into consideration, whether there is any local reservoir effect at the case of samples where it could be problematic. Furthermore the late part of the sediment section (between 15,000 and 30,000 cal. yr BP) has low organic matter content (less than 2-4%) with scarcity of datable plant macrofossil material. In this review a different fraction of pollen samples with terrestrial origin was tested and studied as a novel sample type for the radiocarbon dating. Pollen samples were extracted from the lake sediment cores. This type of organic material could be an ideal candidate for radiocarbon based chronological studies as it has terrestrial source and is present in the whole core in contrast with the terrestrial macrofossils. Although the pollen remains were present in the whole core, in many cases their amount give a challenge even for the AMS technic. Samples were measured with EnvironMICADAS AMS and its gas ion source in the HEKAL laboratory (Debrecen, Hungary). We examine the reliability the

  4. AMS 14 C dating controlled records of monsoon and Indonesian throughflow variability from the eastern Indian Ocean of the past 32,000 years

    Science.gov (United States)

    Li, Z. Y.; Chen, M. T.; Shi, X.; Liu, S.; Wang, H.

    2015-12-01

    Zi-Ye Li a, Min-Te Chen b, Hou-Jie Wang a, Sheng-Fa Liu c, Xue-Fa Shi ca College of Marine Geosciences, Ocean University of China, Qingdao 266100, P.R. Chinab Institute of Applied Geosciences, National Taiwan Ocean University, Keelung, Taiwan 20224, ROCc First Institute of Oceanography, SOA, Qingdao 266100, P.R. China Indonesian throughflow (ITF) is one of the most important currents responsible for transporting heat and moisture from the western Pacific to the Indian Oceans. The ITF is also well-known as effectively in modulating the global climate change with the interactions among ENSO and Asian monsoons. Here we present an AMS 14C dating controlled sea surface temperature (SST) record from core SO184-10043 (07°18.57'S, 105°03.53'E), which was retrieved from 2171m water depth at a north-south depression located at the southeastern offshore area of Sumatera in the eastern Indian Ocean. Based on our high-resolution SST using Mg/Ca analyses based on planktonic foraminifera shells of Globigerinoides ruber and alkenone index, U k'37-SST, oxygen isotope stratigraphy, and AMC 14C age-controls, our records show that, during the past 32,000 years, the SSTs were decreased which imply weaker ITF during Marine Isotope Stage (MIS) 2 and 3. The weaker UTF may respond to strengthened northeast monsoon during the boreal winter. During 21 to 15ka, the southeast monsoon had been stronger and the northeast monsoon was relatively weaker. During 15 to 8ka, rapid sea level rising may allow the opening of the gateways in the Makassar Strait and Lombok Strait that may have further strengthened the ITF. During the early Holocene, the northeast and southeast monsoons seem to be both strengthened. We will discuss the implications of the hydrographic variability and their age uncertainties in this paper during the meeting.

  5. Radiocarbon content in the annual tree rings during last 150 years and time variation of cosmic rays

    Science.gov (United States)

    Kocharov, G. E.; Metskvarishvili, R. Y.; Tsereteli, S. L.

    1985-01-01

    The results of the high accuracy measurements of radiocarbon abundance in precisely dated tree rings in the interval 1800 to 1950 yrs are discussed. Radiocarbon content caused by solar activity is established. The temporal dependence of cosmic rays is constructed, by use of radio abundance data.

  6. 41 CFR 301-11.10 - Am I required to record departure/arrival dates and times on my travel claim?

    Science.gov (United States)

    2010-07-01

    ... departure/arrival dates and times on my travel claim? 301-11.10 Section 301-11.10 Public Contracts and... dates and times on my travel claim? You must record the date of departure from, and arrival at, the... visited. You do not have to record departure/arrival times, but you must annotate your travel claim...

  7. Status of mass spectrometric radiocarbon detection at ETHZ

    Energy Technology Data Exchange (ETDEWEB)

    Seiler, Martin; Maxeiner, Sascha; Wacker, Lukas; Synal, Hans-Arno

    2015-10-15

    A prototype of a mass spectrometric radiocarbon detection instrument without accelerator stage was built for the first time and set into operation at ETH Zurich. The system is designed as an experimental platform to optimize performance of {sup 14}C detection at low ion energies and to study the most relevant processes that may limit system performance. The optimized stripper unit incorporates differential pumping to maintain a low gas outflow and a revised tube design to better match the phase space volume of the ion beam at low energies. The system is fully operational and has demonstrated true radiocarbon dating capabilities. The overall beam transmission through the stripper tube is about 40% for the 1{sup +} charge state. Radiocarbon analyses with an overall precision of 0.6% were obtained on a single sample under regular measurement conditions. By analyzing multiple targets of the same sample material an uncertainty level of 0.3% has been reached. The background level corresponds to a radiocarbon age of 40,000 years.

  8. Millennium scale radiocarbon variations in Eastern North Atlantic thermocline waters: 0-7000 years

    Energy Technology Data Exchange (ETDEWEB)

    Frank, N.; Tisnerat-Laborde, N.; Hatte, C. [LSCE, F-91190 Gif Sur Yvette, (France); Colin, C. [Univ Paris 11, IDES, Orsay, (France); Dottori, M.; Reverdin, G. [Univ Paris 06, LOCEAN, F-75252 Paris, (France)

    2009-07-01

    Complete text of publication follows: Deep water corals are exceptional archives of modern and past ocean circulation as combined U-series and radiocarbon dating allows to reconstruct seawater radiocarbon. Here we present thermocline water radiocarbon concentrations that have been reconstructed for the past {approx} 7000 years for the eastern north Atlantic, based on deep-water corals from Rockall Bank and Porcupine Seabight. We find that thermocline water radiocarbon values follow overall the mean atmospheric long term trend with an average offset of {Delta}{sup 14}C between intermediate water and atmosphere of -55{+-}5 per thousand until 1960 AD. Residual variations are strong ({+-}25 per thousand) over the past 7000 years and there is first evidence that those are synchronous to millennium scale climate variability. Over the past 60 years thermocline water radiocarbon values increase due to the penetration of bomb-radiocarbon into the upper intermediate ocean. Radiocarbon increases by {Delta}{sup 14}C of +95 per thousand compared to +210 per thousand for eastern North Atlantic surface waters. Moreover, bomb-radiocarbon penetration to thermocline depth occurs with a delay of {approx} 10-15 years. Based on high resolution ocean circulation models we suggest that radiocarbon changes at upper intermediate depth are today barely affected by vertical mixing and represent more likely variable advection and mixing of water masses from the Labrador Sea and the temperate Atlantic (including Mediterranean outflow water). Consequently, we assume that residual radiocarbon variations over the past 7000 years reflect millennium scale variability of the Atlantic sub-polar and sub-tropical gyres

  9. Dating the Bibong-ri Neolithic site in Korea: Excavating the oldest ancient boat

    Energy Technology Data Exchange (ETDEWEB)

    Park, Gyujun, E-mail: danielp@kigam.re.k [Geochemical Analysis Center, Geologic Environment Division, Korea Institute of Geoscience and Mineral Resources 305-350 (Korea, Republic of); Kim, Jong-Chan [Department of Physics and Astronomy, Seoul National University, Seoul 151-742 (Korea, Republic of); Youn, Minyoung; Yun, Chongcheol; Kang, Jin; Song, Yong-Mi; Song, Su-Jin; Noh, Hye-Jin [Electrostatic Accelerator Research Center, NCIRF, Seoul National University, Seoul 151-742 (Korea, Republic of); Kim, Do-Kyun [Department of Physics and Astronomy, Seoul National University, Seoul 151-742 (Korea, Republic of); Im, Hack-Jong [Gimhae National Museum, Gimhae, Gyeongsangnam-do 621-060 (Korea, Republic of)

    2010-04-15

    The remains of an ancient wooden boat were unearthed at the Bibong-ri shell mound site. The site was located at Bibong-ri, Bugog-myeon, Changnyeong-gun, Gyeongsangnam-do in South Korea. A substantial fragment of the vessel was discovered in the lowest layer of the site. We collected 17 samples of charcoal and wood from pebble, sand, and shell layers. Sample preparation extracted the carbon from each sample material and converted it into graphite for AMS radiocarbon dating. Radiocarbon dates of the samples indicate that they belong to the Neolithic period and that the boat dates from ca. 5700 BC. To this point, the oldest known boat in the world has been a wooden boat dating from ca. 5500 BC in China. Other ancient boats from around the world include a logboat dating from ca. 3600 BC in Japan and a fleet of wooden boats dating from ca. 3000 BC in Egypt. The Bibong-ri boat is the first boat from the Neolithic period ever found in South Korea and must represent one of the world's oldest known boats.

  10. Increase of radiocarbon concentration in tree rings from Kujawy (SE Poland) around AD 774-775

    Science.gov (United States)

    Rakowski, Andrzej Z.; Krąpiec, Marek; Huels, Mathias; Pawlyta, Jacek; Dreves, Alexander; Meadows, John

    2015-10-01

    Evidence of a rapid increase in atmospheric radiocarbon (14C) content in AD 774-775 was presented by Miyake et al. (2012), who observed an increase of about 12‰ in the 14C content in annual tree rings from Japanese cedar. Usoskin et al. (2013) report a similar 14C spike in German oak, and attribute it to exceptional solar activity. If this phenomenon is global in character, such rapid changes in 14C concentration may affect the accuracy of calibrated dates, as the existing calibration curve is composed mainly of decadal samples. Single-year samples of dendro-chronologically dated tree rings of deciduous oak (Quercus robur) from Kujawy, a village near Krakow (SE Poland), spanning the years AD 765-796, were collected and their 14C content was measured using the AMS system in the Leibniz Laboratory. The results clearly show a rapid increase of 9.2 ± 2.1‰ in the 14C concentration in tree rings between AD 774 and AD 775, with maximum Δ14C = 4.1 ± 2.3‰ noted in AD 776.

  11. Increase of radiocarbon concentration in tree rings from Kujawy (SE Poland) around AD 774–775

    Energy Technology Data Exchange (ETDEWEB)

    Rakowski, Andrzej Z., E-mail: arakowski@polsl.pl [Leibniz-Laboratory for Radiometric Dating and Isotope Research, University Kiel, Max-Eyth-Str. 11-13, 24118 Kiel (Germany); Institute of Physics – Center for Science and Education, Silesian University of Technology, Konarskiego Str. 22B, 44-100 Gliwice (Poland); Krąpiec, Marek [AGH University of Science and Technology, Mickiewicza Av. 30, 30-059 Krakow (Poland); Huels, Mathias [Leibniz-Laboratory for Radiometric Dating and Isotope Research, University Kiel, Max-Eyth-Str. 11-13, 24118 Kiel (Germany); Pawlyta, Jacek [Institute of Physics – Center for Science and Education, Silesian University of Technology, Konarskiego Str. 22B, 44-100 Gliwice (Poland); Dreves, Alexander [Leibniz-Laboratory for Radiometric Dating and Isotope Research, University Kiel, Max-Eyth-Str. 11-13, 24118 Kiel (Germany); Meadows, John [Leibniz-Laboratory for Radiometric Dating and Isotope Research, University Kiel, Max-Eyth-Str. 11-13, 24118 Kiel (Germany); Centre for Baltic and Scandinavian Archaeology, Schleswig-Holstein State Museums Foundation, Schloss Gottorf, Schloßinsel, 24837 Schleswig (Germany)

    2015-10-15

    Evidence of a rapid increase in atmospheric radiocarbon ({sup 14}C) content in AD 774–775 was presented by Miyake et al. (2012), who observed an increase of about 12‰ in the {sup 14}C content in annual tree rings from Japanese cedar. Usoskin et al. (2013) report a similar {sup 14}C spike in German oak, and attribute it to exceptional solar activity. If this phenomenon is global in character, such rapid changes in {sup 14}C concentration may affect the accuracy of calibrated dates, as the existing calibration curve is composed mainly of decadal samples. Single-year samples of dendro-chronologically dated tree rings of deciduous oak (Quercus robur) from Kujawy, a village near Krakow (SE Poland), spanning the years AD 765–796, were collected and their {sup 14}C content was measured using the AMS system in the Leibniz Laboratory. The results clearly show a rapid increase of 9.2 ± 2.1‰ in the {sup 14}C concentration in tree rings between AD 774 and AD 775, with maximum Δ{sup 14}C = 4.1 ± 2.3‰ noted in AD 776.

  12. Rapid revelation of radiocarbon records with laser ablation Accelerator Mass Spectrometry.

    Science.gov (United States)

    Münsterer, Caroline; Wacker, Lukas; Hattendorf, Bodo; Christl, Marcus; Koch, Joachim; Dietiker, Rolf; Synal, Hans-Arno; Günther, Detlef

    2014-01-01

    By focusing high-intensity laser pulses on carbonate samples carbon dioxide is generated and can be directly introduced into the gas ion source (GIS) of an Accelerator Mass Spectrometer (AMS). This new technique allows rapid radiocarbon analyses at high spatial resolution. The design of the deignated laser ablation cell as well as first results on a stalagmite sample are presented.

  13. Radiocarbon chronologies and extinction dynamics of the Late Quaternary mammalian megafauna of the Taimyr Peninsula, Russian Federation

    NARCIS (Netherlands)

    MacPhee, RDE; Tikhonov, AN; Mol, D; Maliave, CD; Van der Plicht, H; Greenwood, AD; Flemming, C; Agenbroad, L; MacPhee, Ross D.E.; Tikhonov, Alexei N.; Marliave, Christian de; Greenwood, Alex D.

    2002-01-01

    This paper presents 75 new radiocarbon dates based on late Quaternary mammal remains recovered from eastern Taimyr Peninsula and adjacent parts of the northern Siberian lowlands, Russian Federation, including specimens of woolly mammoth (Mammuthus primigenius), steppe bison (Bison priscus), muskox (

  14. Appearance and chronology of Textile ceramics in the Middle and Upper Volga region: critical comparison of conventional 14C-, AMS- and typological chronologies

    Directory of Open Access Journals (Sweden)

    Lavento Mika T.

    2015-06-01

    Full Text Available The article offers a comparison of three different methods of chronology construction – conventional 14C (radiocarbon dating, AMS (accelerator mass-spectrometry dating and the so called typological chronology – to date the textile ceramics of the Bronze – Early Iron Age in the Northern Coniferous Zone of Europe, from the Upper and Middle Volga and Kama Rivers to the Baltic region and Scandinavia. The Textile Ceramics Culture (also known as “Net”, “Pseudo-textile”, “Spun-and-speckled” is often associated with a Finnish-speaking community from the Bronze – beginning of the Iron Age. The earliest date of the Textile Ceramics sites on the Middle Oka River is presumably considered to be the 18 th century BC. Datings of the reference sites in the Middle Volga region were fixed within the 15 th – 8 th centuries BC. Comparing these data with the AMS chronology available for the materials from Finland and Estonia, the authors conclude that appearance of the Textile Ceramics was almost synchronous in the Volga and the Baltic regions, although chronology of the early tradition of the Textile Ceramics seems to be different in these areas. The results of yet a small number of AMS dates should be treated only as preliminary. However, AMS-dating seems to be the most efficient tool for further refining of the Textile Ceramics chronology over a vast territory, including in the Volga region.

  15. High Resolution δ18O and δ13C Records of AMS 14C Dated Stalagmites From Jinlun and Yilingyan Caves in Guangxi, China: Climate Variability and Controlling Factors in the Monsoonal Region During the Past 2300 Years

    Science.gov (United States)

    Li, H. C.; Lien, W. Y.; Mii, H. S.; Jiang, G. H.; Chou, C. Y.; Chou, P. J.

    2015-12-01

    Jinlun Cave in Mashan County and Yilingyan Cave in Wuming County are ~120km and ~60km north of Nanning in Guangxi Province under influence of both Indian Monsoon and North Western Pacific Monsoon. Several stalagmites have been dated by AMS 14C dating method since 230Th/U is not applicable due to very low U contents. Twenty (20) AMS 14C dates on Stalagmite JL20131005-10 (10-cm long) show "Bomb carbon curve", spanning the past 60 years. Lamination counting further confirms the chronology. Thirty nine (39) AMS 14C dates on Stalagmite JL20131005-12 (33-cm long) reveal 2300-year continuous growth. Stalagmite YLY20130727-12 (10-cm long) from Yilingyan Cave covers a continuous record of past 2300 years. All studied stalagmites in the caves contain low dead carbon fractions. The annual resolution δ18O and δ13C records obtained from the stalagmites allow us to compare the stalagmite δ18O records with the instrumental rainfall and temperature records, Pacific Decadal Oscillation (PDO), Southern Oscillation Index (SOI), and Sunspot variation, etc. The δ18O and δ13C records exhibit relatively good correlation throughout the time, indicating climatic control on vegetation change. Based on the high-resolution δ18O and δ13C records, we interpret that dry climatic conditions and poor vegetation coverage during periods of AD1880~1850, 1700~1600, 1460~1320, 1210~1280, 860~750, 540~420, 300~220, and AD100~0 shown by increased δ18O and δ13C. The δ18O and δ13C were strongly depleted during the Medieval Warm Period (MWP between AD900 and AD1100) and Current Warm Period (CWP, since AD1900), reflecting strongly increased East Asian Summer Monsoon. After AD1900, the δ13C decreased about 6‰, perhaps indicating human impact on surface vegetation. The δ18O records from the study area are comparable to the published WX42B δ18O record of Wanxiang Cave (Zhang et al., 2008) except for the period of AD1400~1850. Our study suggests that AMS 14C dating is an alternative method for

  16. How to convert biological carbon into graphite for AMS

    Energy Technology Data Exchange (ETDEWEB)

    Getachew, G; Kim, S; Burri, B J; Kelly, P B; Haack, K W; Ognibene, T J; Buchholz, B A; Vogel, J S; Modrow, J; Clifford, A J

    2006-07-27

    Isotope tracer studies, particularly radiocarbon measurements, play a key role in biological, nutritional, and environmental research. Accelerator mass spectrometry (AMS) is now the most sensitive detection method for radiocarbon, but AMS is not widely used in kinetic studies of humans. Part of the reason is the expense, but costs would decrease if AMS were used more widely. One component in the cost is sample preparation for AMS. Biological and environmental samples are commonly reduced to graphite before they are analyzed by AMS. Improvements and mechanization of this multi-step procedure is slowed by a lack of organized educational materials for AMS sample preparation that would allow new investigators to work with the technique without a substantial outlay of time and effort. We present a detailed sample preparation protocol for graphitizing biological samples for AMS and include examples of nutrition studies that have used this procedure.

  17. THE SETTLEMENT DATE OF ICELAND REVISITED

    DEFF Research Database (Denmark)

    Sveinbjornsdottir, Arny E.; Ramsey, Christopher Bronk; Heinemeier, Jan

    2016-01-01

    The settlement time of Iceland has been debated for years as radiocarbon dates of bulk wood samples have been interpreted to set a timing 150-200 yr earlier than indicated by tephrochronology (later than AD 871 +/- 2) and the Sagas (AD 874). This early date is also in conflict with the dating...

  18. L’apport des analyses 14C à l’étude de la nécropole de l’âge du Bronze de“ La Croix de la Mission ” à Marolles-sur-Seine The contribution of radiocarbon dating in the study of the Bronze Age cemetery of Marolles-sur-Seine “ La Croix de la Mission ”

    Directory of Open Access Journals (Sweden)

    Rebecca Peake

    2006-12-01

    Full Text Available Quatorze des 41 sépultures de la nécropole de “ la Croix de la Mission ” à Marolles-sur-Seine ont récemment fait l’objet d’une datation par le radiocarbone aux laboratoires de Groningen (Pays-Bas et de Lyon (France. Les résultats obtenus mettent en évidence l'utilisation en continu de la nécropole pendant plus d’un millénaire entre 2000 et 800 av. n. è. La corrélation entre ces nouvelles dates et les données archéologiques permet de cerner, avec plus de précision, l’éventail des différentes étapes chrono-culturelles représentées à travers les sépultures de la nécropole. [Les analyses 14C ont été effectuées par les laboratoires de Groningen (Centrum voor Isotopen Onderzoek Rijksuniversiteit Groningen Nijenborgh 4 NL-9747 AG Groningen et Lyon (Centre de Datation par le Radiocarbone Université Claude Bernard Lyon 1, 43, bd du 11 Novembre 1918 F-69622 Villeurbanne Cedex.]Fourteen of the 41 burials of the “ la Croix de la Mission ” Bronze Age cemetery at Marolles-sur-Seine have recently been carbon dated by the Lyon (France and Groningen (Netherlands laboratories. These new dates confirm the site’s occupation for more than 1000 years from 2000 BC to 800 BC and determine more precisely the different cultural and chronological phases of the cemetery illustrated by the great range of its burials.

  19. Age models for peat deposits on the basis of coupled lead-210 and radiocarbon data.

    Science.gov (United States)

    Piotrowska, Natalia; de Vleeschouwer, François; Sikorski, Jarosław; Sensuła, Barbara; Michczyński, Adam; Fiałkiewicz-Kozieł, Barbara; Palowski, Bernard

    2010-05-01

    The study presents three examples of age-model construction based on the results of 210Pb and 14C dating methods applied to peat deposits. The three sites are ombrotrophic peat bogs: the Misten (Belgium), Slowinskie Bloto (N Poland) and Puscizna Mala (S Poland). All sites have been subjected to multiproxy studies aimed at reconstructing paleoenvironment and human activity, covering the last 1500, 1300 and 1800 years, respectively (De Vleeschouwer et al. 2009A, 2009B, in prep., Fialkiewicz-Koziel, ongoing PhD). A detailed comparison between 210Pb and post-bomb 14C results in the Misten bog has also been carried out by Piotrowska et al. (2009). In all cores, the 210Pb activity was calculated using 210Po and 208Po activities after acid-extraction from bulk samples, subsequent deposition on silver discs and measurements by alpha spectrometry. Unsupported 210Pb was detected until 35cm in Slowinskie Bloto, 15cm in the Misten and 19cm in Puscizna Mala. Constant Rate of Supply (CRS) model was then applied to compute ages of each 1-cm core interval. For the Misten and Slowinskie Bloto, radiocarbon measurements were performed on selected aboveground plant macrofossils, mainly Sphagnum spp. or Calluna vulgaris, Erica tetralix, and Andromeda polyfolia. Radiocarbon ages were determined using accelerator mass spectrometry (AMS) after acid-alkali-acid wash, combustion, purification of carbon dioxide and graphitisation. For Puscizna Mala bulk samples were dated after chemical preparation of benzene for liquid scintillation counting (LSC) or CO2 for gas proportional counting (GPC). Radiocarbon calibration was undertaken using the Intcal04 calibration curve and OxCal 4 software. As a priori information the 210Pb-derived ages were used in a P_Sequence model (Bronk Ramsey, 2008). A number of dates characterized by low agreement with stratigraphical order had to be considered as outliers and rejected from the final age model. For building a continuous age models a non-linear approach

  20. Preliminary report on radiocarbon dating of cryptoendolithic microorganisms

    Science.gov (United States)

    Bonani, G.; Friedmann, E. I.; Ocampo-Friedmann, R.; McKay, C. P.; Woelfli, W.

    1988-01-01

    The existence of microbial communities living inside desert rocks has been reported by FRIEDMANN et al. (1967, 1976), first in rocks collected from the hot and dry Negev desert and later in rocks in the frigid Ross Desert of Southern Victoria Land, Antarctica. The extremely inhospitable climatic conditions in both places has led to the suggestion that these organisms have very low rates of metabolism and may, in addition, be very old (FRIEDMANN 1982). Our preliminary measurements showed a 14C deficiency indicating a carbon age in the order of magnitude of 10(3) years.

  1. PRIME lab AMS performance, upgrades and research applications

    Energy Technology Data Exchange (ETDEWEB)

    Sharma, P. E-mail: sharma@purdue.edu; Bourgeois, M.; Elmore, D.; Granger, D.; Lipschutz, M.E.; Ma, X.; Miller, T.; Mueller, K.; Rickey, F.; Simms, P.; Vogt, S

    2000-10-01

    The Purdue Rare Isotope Measurement Laboratory (PRIME Lab) is a dedicated research and service facility for AMS that provides the scientific community with timely, reliable and high quality chemical processing ({approx}600 samples/year) and AMS measurements ({approx}3000 samples/year) of {sup 10}Be, {sup 14}C, {sup 26}Al, {sup 36}Cl, {sup 41}Ca and {sup 129}I. The AMS system is based on an upgraded FN (7 MV) tandem accelerator that has recently been modified to improve performance. The precision is 1% for {sup 14}C and it is 3-5% for the other nuclides for radioisotope/stable isotope ratios at the 10{sup -12} levels. System background for {sup 10}Be, {sup 14}C, {sup 26}Al, {sup 36}Cl and {sup 41}Ca is 1-10x10{sup -15} while for {sup 129}I the natural abundance limits it to 20x10{sup -15}. Research is being carried out in Earth, planetary, and biomedical sciences. Geoscience applications include determination of exposure ages of glacial moraines, volcanic eruptions, river terraces, and fault scarps. Burial histories of sand are being determined to decipher the timing of human expansion and climatic history. Environmental applications are tracing the release of radioactivity from nuclear fuel reprocessing plants, water tracing, and neutron dosimetry. The applications using meteoric nuclides are oil field brines, sediment subduction, radiocarbon dating, and groundwater {sup 36}Cl mapping. Radionuclide concentrations are also determined in meteorites and tektites for deciphering space and terrestrial exposure histories.

  2. Agriculture, population growth, and statistical analysis of the radiocarbon record.

    Science.gov (United States)

    Zahid, H Jabran; Robinson, Erick; Kelly, Robert L

    2016-01-26

    The human population has grown significantly since the onset of the Holocene about 12,000 y ago. Despite decades of research, the factors determining prehistoric population growth remain uncertain. Here, we examine measurements of the rate of growth of the prehistoric human population based on statistical analysis of the radiocarbon record. We find that, during most of the Holocene, human populations worldwide grew at a long-term annual rate of 0.04%. Statistical analysis of the radiocarbon record shows that transitioning farming societies experienced the same rate of growth as contemporaneous foraging societies. The same rate of growth measured for populations dwelling in a range of environments and practicing a variety of subsistence strategies suggests that the global climate and/or endogenous biological factors, not adaptability to local environment or subsistence practices, regulated the long-term growth of the human population during most of the Holocene. Our results demonstrate that statistical analyses of large ensembles of radiocarbon dates are robust and valuable for quantitatively investigating the demography of prehistoric human populations worldwide.

  3. Improving estimates of surface water radiocarbon reservoir ages in the northeastern Atlantic Ocean.

    Science.gov (United States)

    Greenop, Rosanna; Burke, Andrea; Rae, James; Austin, William; Reimer, Paula; Blaauw, Maarten; Crocker, Anya; Chalk, Thomas; Barker, Stephen; Knutz, Paul; Hall, Ian

    2016-04-01

    Radiocarbon measurements from foraminifera in marine sediment cores are widely used to constrain age models and the timing of paleoceanographic events, as well as past changes in ocean circulation and carbon cycling. However, the use of radiocarbon for both dating and palaeoceanographic applications is limited in sediment cores by a lack of knowledge about the surface ocean radiocarbon reservoir age and how it varies in both space and time. Typically, to convert a planktic radiocarbon age into a calendar age, an assumed constant reservoir age is applied. However, there is mounting evidence to suggest that this assumption of constant reservoir age through time is an oversimplification, particularly for the high latitude oceans during the cold climates of the last glacial and deglacial periods. Here we present new high-resolution radiocarbon records together with tephra tie points and 230-thorium (230Th) constrained sedimentation rates to improve estimates of radiocarbon reservoir age in the Northeast Atlantic Ocean. In addition we will explore the impact of the new reservoir ages for both the age models of the cores studied, as well as the palaeoceanographic implications of these reservoir age changes during intervals of rapid climate change over the past 40,000 years.

  4. Youngest radiocarbon age for Jefferson's ground sloth, Megalonyx jeffersonii (Xenarthra, Megalonychidae)

    Science.gov (United States)

    Gregory McDonald, H.; Stafford, Thomas W.; Gnidovec, Dale M.

    2015-03-01

    A partial skeleton of the extinct ground sloth, Megalonyx jeffersonii, recovered from a farm near Millersburg, Ohio in 1890, was radiocarbon dated for the first time. The ungual dated is part of a skeleton mounted for exhibit at the Orton Geological Museum at Ohio State University and was the first mounted skeleton of this animal. From its initial discovery the bones were treated with multiple organic compounds that had the potential to compromise the radiocarbon age and the specimen required special treatments in order to obtain a valid radiocarbon age. The 14C measurement on the ungual from this skeleton (11,235 ± 40 14C yr BP = 13,180-13,034 cal yr BP) is the youngest 14C age presently determined for M. jeffersonii.

  5. Performance report for the low energy compact radiocarbon accelerator mass spectrometer at Uppsala University

    Energy Technology Data Exchange (ETDEWEB)

    Salehpour, M., E-mail: mehran.salehpour@physics.uu.se [Department of Physics and Astronomy, Ion Physics, Applied Nuclear Physics Division, P.O. Box 516, SE-751 20 Uppsala (Sweden); Håkansson, K.; Possnert, G. [Department of Physics and Astronomy, Ion Physics, Applied Nuclear Physics Division, P.O. Box 516, SE-751 20 Uppsala (Sweden); Wacker, L.; Synal, H.-A. [Ion Physics, ETH Zurich, Otto-Stern-Weg 5, 8093 (Switzerland)

    2016-03-15

    A range of ion beam analysis activities are ongoing at Uppsala University, including Accelerator Mass Spectrometry (AMS). Various isotopes are used for AMS but the isotope with the widest variety of applications is radiocarbon. Up until recently, only the 5 MV Pelletron tandem accelerator had been used at our site for radiocarbon AMS, ordinarily using 12 MeV {sup 14,13,12}C{sup 3+} ions. Recently a new radiocarbon AMS system, the Green-MICADAS, developed at the ion physics group at ETH Zurich, was installed. The system has a number of outstanding features which will be described. The system operates at a terminal voltage of 175 kV and uses helium stripper gas, extracting singly charged carbon ions. The low- and high energy mass spectrometers in the system are stigmatic dipole permanent magnets (0.42 and 0.97 T) requiring no electrical power nor cooling water. The system measures both the {sup 14}C/{sup 12}C and the {sup 13}C/{sup 12}C ratios on-line. Performance of the system is presented for both standard mg samples as well as μg-sized samples.

  6. Performance report for the low energy compact radiocarbon accelerator mass spectrometer at Uppsala University

    Science.gov (United States)

    Salehpour, M.; Håkansson, K.; Possnert, G.; Wacker, L.; Synal, H.-A.

    2016-03-01

    A range of ion beam analysis activities are ongoing at Uppsala University, including Accelerator Mass Spectrometry (AMS). Various isotopes are used for AMS but the isotope with the widest variety of applications is radiocarbon. Up until recently, only the 5 MV Pelletron tandem accelerator had been used at our site for radiocarbon AMS, ordinarily using 12 MeV 14,13,12C3+ ions. Recently a new radiocarbon AMS system, the Green-MICADAS, developed at the ion physics group at ETH Zurich, was installed. The system has a number of outstanding features which will be described. The system operates at a terminal voltage of 175 kV and uses helium stripper gas, extracting singly charged carbon ions. The low- and high energy mass spectrometers in the system are stigmatic dipole permanent magnets (0.42 and 0.97 T) requiring no electrical power nor cooling water. The system measures both the 14C/12C and the 13C/12C ratios on-line. Performance of the system is presented for both standard mg samples as well as μg-sized samples.

  7. Atmospheric radiocarbon calibration to 45,000 yr BP : Late glacial fluctuations and cosmogenic isotope production

    NARCIS (Netherlands)

    Kitagawa, H; van der Plicht, J

    1998-01-01

    More than 250 carbon-14 accelerator mass spectrometry dates of terrestrial macrofossils from annually laminated sediments from Lake Suigetsu (Japan) provide a first atmospheric calibration for almost the total range of the radiocarbon method (45,000 years before the present), The results confirm the

  8. Radiocarbon evidence for a smaller oceanic carbon dioxide sink than previously believed

    Energy Technology Data Exchange (ETDEWEB)

    Hesshaimer, Vago; Levin, Ingeborg (Heidelberg Univ. (Germany). Inst. fuer Umweltphysik); Heimann, Martin (Max-Planck-Institut fuer Meteorologie, Hamburg (Germany))

    1994-07-21

    Radiocarbon produced naturally in the upper atmosphere or artificially during nuclear weapons testing is the main tracer used to validate models of oceanic carbon cycling, in particular the exchange of carbon dioxide with the atmosphere and the mixing parameters within the ocean itself. Here we test the overall consistency of exchange fluxes between all relevant compartments in a simple model of the global carbon cycle, using measurements of the long-term tropospheric CO[sub 2] concentration and radiocarbon composition, the bomb [sup 14]C inventory in the stratosphere and a compilation of bomb detonation dates and strengths. (author).

  9. Marine04 Marine radiocarbon age calibration, 26 ? 0 ka BP

    Energy Technology Data Exchange (ETDEWEB)

    Hughen, K; Baille, M; Bard, E; Beck, J; Bertrand, C; Blackwell, P; Buck, C; Burr, G; Cutler, K; Damon, P; Edwards, R; Fairbanks, R; Friedrich, M; Guilderson, T; Kromer, B; McCormac, F; Manning, S; Bronk-Ramsey, C; Reimer, P; Reimer, R; Remmele, S; Southon, J; Stuiver, M; Talamo, S; Taylor, F; der Plicht, J v; Weyhenmeyer, C

    2004-11-01

    New radiocarbon calibration curves, IntCal04 and Marine04, have been constructed and internationally ratified to replace the terrestrial and marine components of IntCal98. The new calibration datasets extend an additional 2000 years, from 0-26 ka cal BP (Before Present, 0 cal BP = AD 1950), and provide much higher resolution, greater precision and more detailed structure than IntCal98. For the Marine04 curve, dendrochronologically dated tree-ring samples, converted with a box-diffusion model to marine mixed-layer ages, cover the period from 0-10.5 ka cal BP. Beyond 10.5 ka cal BP, high-resolution marine data become available from foraminifera in varved sediments and U/Th-dated corals. The marine records are corrected with site-specific {sup 14}C reservoir age information to provide a single global marine mixed-layer calibration from 10.5-26.0 ka cal BP. A substantial enhancement relative to IntCal98 is the introduction of a random walk model, which takes into account the uncertainty in both the calendar age and the radiocarbon age to calculate the underlying calibration curve. The marine datasets and calibration curve for marine samples from the surface mixed layer (Marine04) are discussed here. The tree-ring datasets, sources of uncertainty, and regional offsets are presented in detail in a companion paper by Reimer et al.

  10. Future directions of the AMS program at Lucas Heights

    Energy Technology Data Exchange (ETDEWEB)

    Tuniz, C. [Australian Nuclear Science and Technology Organisation, Lucas Heights, NSW (Australia)

    1998-12-31

    The research program based on the ANTARES AMS spectrometer involves applications of the long-lived radionuclides {sup 14}C, {sup 10}Be, {sup 26}Al, {sup 36}Cl and {sup 129}I in earth sciences and archaeology. Examples of environmental applications of AMS at Lucas Heights include: use of the {sup 14}C bomb pulse to determine the age and age-spread of air trapped in Antarctic ice bubbles, key parameters to study the variability of CO{sub 2} and other greenhouse gases in the past; analyses of {sup 14}C bomb-pulse curves in tree rings from tropical regions and the southern hemisphere to improve our understanding of the carbon cycle and air-sea interactions, important processes for the global climate; analyses of {sup 10}Be and {sup 36}Cl produced in-situ in polished glacial bedrock and moraine boulders from Tasmania, New Zealand and Antarctica, as part of a major national project to unravel the timing of glacial cycles in the southern hemisphere. A recent archaeological application has been the radiocarbon dating of charcoal fragments from the rock shelter at Jinmium in the Northern Territory demonstrating that this site was occupied by Aboriginal people only during the late Holocene. In environmental monitoring, the analysis of {sup 129}I, {sup 14}C and {sup 36}Cl in water specimens from Mururoa and Fangatauga contributed to an IAEA study regarding residual radioactivity in the Pacific after the French nuclear program Extended abstract. 5 refs.

  11. Age estimation in forensic sciences: Application of combined aspartic acid racemization and radiocarbon analysis

    Energy Technology Data Exchange (ETDEWEB)

    Alkass, K; Buchholz, B A; Ohtani, S; Yamamoto, T; Druid, H; Spalding, S L

    2009-11-02

    Age determination of unknown human bodies is important in the setting of a crime investigation or a mass disaster, since the age at death, birth date and year of death, as well as gender, can guide investigators to the correct identity among a large number of possible matches. Traditional morphological methods used by anthropologists to determine age are often imprecise, whereas chemical analysis of tooth dentin, such as aspartic acid racemization has shown reproducible and more precise results. In this paper we analyze teeth from Swedish individuals using both aspartic acid racemization and radiocarbon methodologies. The rationale behind using radiocarbon analysis is that above-ground testing of nuclear weapons during the cold war (1955-1963) caused an extreme increase in global levels of carbon-14 ({sup 14}C) which have been carefully recorded over time. Forty-four teeth from 41 individuals were analyzed using aspartic acid racemization analysis of tooth crown dentin or radiocarbon analysis of enamel and ten of these were split and subjected to both radiocarbon and racemization analysis. Combined analysis showed that the two methods correlated well (R2=0.66, p < 0.05). Radiocarbon analysis showed an excellent precision with an overall absolute error of 0.6 {+-} 04 years. Aspartic acid racemization also showed a good precision with an overall absolute error of 5.4 {+-} 4.2 years. Whereas radiocarbon analysis gives an estimated year of birth, racemization analysis indicates the chronological age of the individual at the time of death. We show how these methods in combination can also assist in the estimation of date of death of an unidentified victim. This strategy can be of significant assistance in forensic casework involving dead victim identification.

  12. Complexities in the Use of Bomb-Curve Radiocarbon to Determine Time Since Death of Human Skeletal Remains

    Energy Technology Data Exchange (ETDEWEB)

    Ubelaker, D H; Buchholz, B A

    2005-04-26

    Atmospheric testing of nuclear weapons during the 1950s and early 1960s doubled the level of radiocarbon ({sup 14}C) in the atmosphere. From the peak in 1963, the level of {sup 14}CO{sub 2} has decreased exponentially with a mean life of about 16 years, not due to radioactive decay, but due to mixing with large marine and terrestrial carbon reservoirs. Since radiocarbon is incorporated into all living things, the bomb-pulse is an isotopic chronometer of the past half century. The absence of bomb radiocarbon in skeletonized human remains generally indicates a date of death before 1950. Comparison of the radiocarbon values with the post 1950 bomb-curve may also help elucidate when in the post 1950 era, the individual was still alive. Such interpretation however, must consider the age at death of the individual and the type of tissue sampled.

  13. Aspartic acid racemization dating of Holocene brachiopods and bivalves from the southern Brazilian shelf, South Atlantic

    Science.gov (United States)

    Barbour Wood, Susan L.; Krause, Richard A.; Kowalewski, Michał; Wehmiller, John; Simões, Marcello G.

    2006-09-01

    The extent of racemization of aspartic acid (Asp) has been used to estimate the ages of 9 shells of the epifaunal calcitic brachiopod Bouchardia rosea and 9 shells of the infaunal aragonitic bivalve Semele casali. Both taxa were collected concurrently from the same sites at depths of 10 m and 30 m off the coast of Brazil. Asp D/L values show an excellent correlation with radiocarbon age at both sites and for both taxa ( r2Site 9 B. rosea = 0.97, r2Site 1 B. rosea = 0.997, r2Site 9 S. casali = 0.9998, r2Site 1 S. casali = 0.93). The Asp ratios plotted against reservoir-corrected AMS radiocarbon ages over the time span of multiple millennia can thus be used to develop reliable and precise geochronologies not only for aragonitic mollusks (widely used for dating previously), but also for calcitic brachiopods. At each collection site, Bouchardia specimens display consistently higher D/L values than specimens of Semele. Thermal differences between sites are also notable and in agreement with theoretical expectations, as extents of racemization for both taxa are greater at the warmer, shallower site than at the cooler, deeper one. In late Holocene marine settings, concurrent time series of aragonitic and calcitic shells can be assembled using Asp racemization dating, and parallel multi-centennial to multi-millennial records can be developed simultaneously for multiple biomineral systems.

  14. Growth rate determinations from radiocarbon in bamboo corals (genus Keratoisis)

    Science.gov (United States)

    Farmer, Jesse R.; Robinson, Laura F.; Hönisch, Bärbel

    2015-11-01

    Radiocarbon (14C) measurements are an important tool for determining growth rates of bamboo corals, a cosmopolitan group of calcitic deep-sea corals. Published growth rate estimates for bamboo corals are highly variable, with potential environmental or ecological drivers of this variability poorly constrained. Here we systematically investigate the application of 14C for growth rate determinations in bamboo corals using 55 14C dates on the calcite and organic fractions of six bamboo corals (identified as Keratoisis sp.) from the western North Atlantic Ocean. Calcite 14C measurements on the distal surface of these corals and five previously published bamboo corals exhibit a strong one-to-one relationship with the 14C of dissolved inorganic carbon (DI14C) in ambient seawater (r2=0.98), confirming the use of Keratoisis sp. calcite 14C as a proxy for seawater 14C activity. Radial growth rates determined from 14C age-depth regressions, 14C plateau tuning and bomb 14C reference chronologies range from 12 to 78 μm y-1, in general agreement with previously published radiometric growth rates. We document potential biases to 14C growth rate determinations resulting from water mass variability, bomb radiocarbon, secondary infilling (ontogeny), and growth rate nonlinearity. Radial growth rates for Keratoisis sp. specimens do not correlate with ambient temperature, suggesting that additional biological and/or environmental factors may influence bamboo coral growth rates.

  15. Rarotonga Radiocarbon (delta 14C) for 1950 to 1997

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Rarotonga coral radiocarbon (14C) timeseries. Coral radiocarbon (Delta-14C) on untreated, low-speed drilled samples. Precision is +/- 4 per mil as documented by an...

  16. Contamination on AMS Sample Targets by Modern Carbon is Inevitable

    NARCIS (Netherlands)

    Paul, Dipayan; Been, Henk A.; Aerts-Bijma, Anita Th.; Meijer, Harro A.J.

    2016-01-01

    Accelerator mass spectrometry (AMS) measurements of the radiocarbon content in very old samples are often challenging and carry large relative uncertainties due to possible contaminations acquired during the preparation and storage steps. In case of such old samples, the natural surrounding levels o

  17. CONTAMINATION ON AMS SAMPLE TARGETS BY MODERN CARBON IS INEVITABLE

    NARCIS (Netherlands)

    Paul, Dipayan; Been, Henk A.; Aerts-Bijma, Anita Th; Meijer, Harro A. J.

    2016-01-01

    Accelerator mass spectrometry (AMS) measurements of the radiocarbon content in very old samples are often challenging and carry large relative uncertainties due to possible contaminations acquired during the preparation and storage steps. In case of such old samples, the natural surrounding levels o

  18. Construction of reliable radiocarbon-based chronologies for speleothems

    Science.gov (United States)

    Lechleitner, Franziska; Fohlmeister, Jens; McIntyre, Cameron; Baldini, Lisa M.; Jamieson, Robert A.; Hercman, Helena; Gasiorowski, Michal; Pawlak, Jacek; Stefaniak, Krzysztof; Socha, Pawel; Eglinton, Timothy I.; Baldini, James U. L.

    2016-04-01

    Speleothems have become one of the most widely applied archives for paleoclimate research. One of their key advantages is their amenability for U-series dating, often producing excellent high precision chronologies. However, stalagmites with high detrital Th or very low U concentrations are problematic to date using U-series, and sometimes need to be discarded from further paleoclimate analysis. Radiocarbon chronologies could present an alternative for stalagmites that cannot be dated using U-series, if offsets from the "dead carbon fraction" (DCF) can be resolved. The DCF is a variable reservoir effect introduced by the addition of 14C-dead carbon from host rock dissolution and soil organic matter. We present a novel age modeling technique that provides accurate 14C-based chronologies for stalagmites. As this technique focuses on the long-term decay pattern of 14C, it is only applicable on stalagmites that show no secular variability in their 14C-depth profiles, but is independent of short-term DCF variations. In order to determine whether a stalagmite is suitable for this method without direct knowledge of long-term trends in the DCF, we highlight how other geochemical proxies (δ13C, Mg/Ca) can provide additional information on changes in karst hydrology, soil conditions, and climate that would affect DCF. We apply our model on a previously published U-Th dated stalagmite 14C dataset from Heshang Cave, China with excellent results, followed by a previously 'undateable' stalagmite from southern Poland.

  19. Radiocarbon signal of a low and intermediate level radioactive waste disposal facility in nearby trees.

    Science.gov (United States)

    Janovics, R; Kelemen, D I; Kern, Z; Kapitány, S; Veres, M; Jull, A J T; Molnár, M

    2016-03-01

    Tree ring series were collected from the vicinity of a Hungarian radioactive waste treatment and disposal facility and from a distant control background site, which is not influenced by the radiocarbon discharge of the disposal facility but it represents the natural regional (14)C level. The (14)C concentration of the cellulose content of tree rings was measured by AMS. Data of the tree ring series from the disposal facility was compared to the control site for each year. The results were also compared to the (14)C data of the atmospheric (14)C monitoring stations at the disposal facility and to international background measurements. On the basis of the results, the excess radiocarbon of the disposal facility can unambiguously be detected in the tree from the repository site.

  20. Amino acid racemisation dating

    Energy Technology Data Exchange (ETDEWEB)

    Murray-Wallace, C.V. [University of Wollongong, Wollongong, NSW (Australia). School of Geosciences

    1999-11-01

    The potential of the time-dependent amino acid racemisation reaction as a method of age assessment was first reported by Hare and Abelson (1968). They noted that in specimens of the bivalve mollusc Mercenaria sp., greater concentrations of amino acids in the D-configuration with increasing fossil age. Hare and Abelson (1968) also reported negligible racemisation in a modern specimen of Mecanaria sp. On this basis they suggested that the extent of amino acid racemisation (epimerisation in the case of isoleucine) may be used to assess the age of materials within and beyond the range of radiocarbon dating. For the past thirty years amino acid racemisation has been extensively applied in Quaternary research as a method of relative and numeric dating, and a particularly large literature has emerged on the subject 12 refs.

  1. Atmospheric Radiocarbon Calibration to 45,000 yr B.P. : Late Glacial Fluctuations and Cosmogenic Isotope Production

    NARCIS (Netherlands)

    Kitagawa, H.; Plicht, J. van der

    1998-01-01

    More than 250 carbon-14 accelerator mass spectrometry dates of terrestrial macrofossils from annually laminated sediments from Lake Suigetsu (Japan) provide a first atmospheric calibration for almost the total range of the radiocarbon method (45,000 years before the present). The results confirm the

  2. The Keck Carbon Cycle AMS Laboratory, U.C.I.: Initial operation and a background surprise

    OpenAIRE

    Southon, John R.; Santos, Guaciara M.; Druffel-Rodriguez, K C; Druffel, Ellen R. M.; Trumbore, Susan E.; Xu, Xiaomei; Griffin, Sheila; Ali, S.; Mazon, M.

    2003-01-01

    A new 14C accelerator mass spectrometry (AMS) laboratory for carbon cycle studies has been established at the University of California, Irvine. The 0.5 MV AMS system was installed in mid-2002 and has operated routinely since October of that year. This paper briefly describes the spectrometer and summarizes lessons learned during the first year of operation. In the process of setting up the system, we identified and largely suppressed a previously unreported radiocarbon AMS b...

  3. Application of Bomb Radiocarbon Chronologies to Shortfin Mako (Isurus oxyrinchus)

    Energy Technology Data Exchange (ETDEWEB)

    Ardizzone, D; Cailliet, G M; Natanson, L J; Andrews, A H; Kerr, L A; Brown, T A

    2007-07-16

    and the number of samples for MIA analysis was insufficient for some months. Hence, unequivocal validation of shortfin mako age estimates has yet to be accomplished. Atmospheric testing of thermonuclear devices in the 1950s and 1960s effectively doubled the natural atmospheric radiocarbon ({sup 14}C). The elevated {sup 14}C levels were first recorded in 1957-58, with a peak around 1963. As a consequence, {sup 14}C entered the ocean through gas exchange with the atmosphere at the ocean surface and in terrestrial runoff. Despite variable oceanographic conditions, a worldwide rise of the bomb {sup 14}C signal entered the ocean mixed layer as dissolved inorganic carbon (DIC) in 1957-58. The large amounts of {sup 14}C released from the bomb tests produced a signature that can be followed through time, throughout the marine food web, and into deeper waters. The marked increase of radiocarbon levels was first measured in the DIC of seawater and in biogenic marine carbonates of hermatypic corals in Florida. Subsequently, this record was documented in corals from other regions and in the thallus of rhodoliths. The accumulation of radiocarbon in the hard parts of most marine organisms in the mixed layer (such as fish otoliths and bivalves) was synchronous with the coral time-series. This technique has been used to validate age estimates and longevity of numerous bony fishes to date, as well as to establish bomb radiocarbon chronologies from different oceans. In the first application of this technique to lamnoid sharks, validated annual band-pair deposition in vertebral growth bands for the porbeagle (Lamna nasus) aged up to 26 years. Radiocarbon values from samples obtained from 15 porbeagle caught in the western North Atlantic Ocean (some of which were known-age) produced a chronology similar in magnitude to the reference carbonate chronology for that region. The observed phase shift of about 3 years was attributed to different sources of carbon between vertebrae and those for

  4. Radiocarbon challenges archaeo-historical time frameworks in the near East : The Early Bronze Age of Jericho in relation to Egypt

    NARCIS (Netherlands)

    Bruins, HJ; van der Plicht, J; Bruins, Hendrik J.; Boaretto, E.; Carmi, I.

    2001-01-01

    Our stratified radiocarbon dates from EB Jericho (Trench III) on short-lived material are significantly older than conventional archaeo-historical time frameworks. The calibrated (14)C date of Stage XV Phase li-lii (Early to Middle EB-I Kenyon) is 100-450 years older. Stage XVI Phase lxi-lxii (Early

  5. Accelerator Mass Spectrometry (AMS) 1977-1987

    Science.gov (United States)

    Gove, H. E.; Purser, K. H.; Litherland, A. E.

    2010-04-01

    The eleventh Accelerator Mass Spectrometry (AMS 11) Conference took place in September 2008, the Thirtieth Anniversary of the first Conference. That occurred in 1978 after discoveries with nuclear physics accelerators in 1977. Since the first Conference there have now been ten further conferences on the development and applications of what has become known as AMS. This is the accepted acronym for the use of accelerators, together with nuclear and atomic physics techniques, to enhance the performance of mass spectrometers for the detection and measurement of rare long-lived radioactive elements such as radiocarbon. This paper gives an outline of the events that led to the first conference together with a brief account of the first four conferences before the introduction of the second generation of accelerator mass spectrometers at AMS 5.

  6. DATING OF LATE PLEISTOCENE TREE-RING SERIES FROM JAPAN

    NARCIS (Netherlands)

    van der Plicht, J.; Imamura, M.; Sakamoto, M.; Boaretto, E.; Rebollo Franco, N.R.

    2012-01-01

    We have radiocarbon dated series of tree rings from 2 fossil trees (named ND-113 and the Fuji tree) buried in fossil volcanic avalanche deposits in Japan. They are dendrochronologically floating, dating beyond the tree-ring part of the C-14 calibration curve. The trees show about 350 and 400 annual

  7. Status of the “new” AMS facility in Trondheim

    Energy Technology Data Exchange (ETDEWEB)

    Nadeau, Marie-Josée; Vaernes, Einar; Svarva, Helene Løvstrand; Larsen, Eiliv; Gulliksen, Steinar [Department of Archaeometry, Norwegian University of Science and Technology, 7491 Trondheim (Norway); Klein, Matthias; Mous, Dirk J.W. [High Voltage Engineering Europa B.V., P.O. Box 99, 3800 AB Amersfoort (Netherlands)

    2015-10-15

    The Radiocarbon Laboratory of the Norwegian University of Science and Technology (NTNU) in Trondheim has a long history, dating back to the 1950s. Its relatively new AMS facility is based on a 1 MV Tandetron from High Voltage Engineering Europa B.V. that is equipped with a hybrid solid/gas SO-110 ion source, a low energy spectrometer supporting sequential injection, a high energy analysis system consisting of a magnet and an electrostatic deflector, allowing insertion of an absorber foil for isobar suppression, and a two dimensional gas ionisation detector (E and ΔE). The system is at present capable of measuring {sup 10}Be, {sup 14}C, and {sup 26}Al and can be easily modified to measure isotopes of higher masses. Acceptance tests results for {sup 10}Be{sup 1+}, {sup 14}C{sup 2+}, {sup 26}Al{sup 1+}, and {sup 26}Al{sup 3+} are presented. The laboratory measures only {sup 14}C at present and the routine procedures are described. The system has demonstrated a very low background (70,000 {sup 14}C years BP or 2·10{sup −16} on Alfa Aesar 40795 graphite powder, −200 mesh, 99.9995%) for {sup 14}C when charge state 2+ is measured and the interference of Li ions in the detector is minimal. Some ion optical peculiarities of the system are also discussed.

  8. Radiocarbon measurements at LAC-UFF: Recent performance

    Energy Technology Data Exchange (ETDEWEB)

    Linares, Roberto, E-mail: rlinares@if.uff.br [Laboratório de Radiocarbono, Universidade Federal Fluminense, Av. Gal. Milton Tavares de Souza, s/n, Niterói 24230-346 (Brazil); Macario, Kita D. [Laboratório de Radiocarbono, Universidade Federal Fluminense, Av. Gal. Milton Tavares de Souza, s/n, Niterói 24230-346 (Brazil); Santos, Guaciara M. [Earth System Science, University of California, Irvine, B321 Croul Hall, Irvine, CA 92697-3100 (United States); Carvalho, Carla [Laboratório de Radiocarbono, Universidade Federal Fluminense, Av. Gal. Milton Tavares de Souza, s/n, Niterói 24230-346 (Brazil); Departamento de Geoquímica, Universidade Federal Fluminense, Outeiro São João Batista, s/n, Niterói 24020-141 (Brazil); Santos, Hellen C. dos; Gomes, Paulo R.S.; Castro, Maikel D.; Oliveira, Fabiana M.; Alves, Eduardo Q. [Laboratório de Radiocarbono, Universidade Federal Fluminense, Av. Gal. Milton Tavares de Souza, s/n, Niterói 24230-346 (Brazil)

    2015-10-15

    In 2012 a single stage accelerator mass spectrometer from NEC was installed at the Radiocarbon Laboratory of Universidade Federal Fluminense (LAC-UFF), Niterói, Brazil. Here, we present a status report of our facility. We discuss some modifications applied to our combustion protocol in an attempt to reduce our procedural blank, mostly to processed organic samples. Measurements of reference materials indicate low precision and accuracy that are partially related to beam optics through the acceleration tube. We observed that once the beam current intensity increases the measured {sup 13}C{sup +}/{sup 12}C{sup +} becomes erratic. Therefore, in order to maintain the AMS-δ{sup 13}C values within reasonable values, so that fractionation corrections using the spectrometer {sup 13}C{sup +}/{sup 12}C{sup +} values does not affect the final {sup 14}C results, we are forced to limit the {sup 12}C{sup −} beam intensity to ⩽30 μA. This requirement was confirmed during our accuracy tests, when measuring selected annual tree-rings wood samples from a Parana pine (Araucaria angustifolia) between 1927 and 1997 previously measured at the Keck Carbon Cycle AMS Facility (KCCAMS), at the University of California, Irvine (UCI). At the LAC-UFF tree-ring wood samples were processed and measured in 4 different batches during a period of about 5 months. The {sup 14}C results were later compared to the high-precision data obtained at KCCAMS/UCI and reached a good agreement. Recently a problem associated with graphitization yield were finally identified and new measurements with secondary standards are promising.

  9. Extracting growth rates from the non-laminated coralline sponge Astrosclera willeyana using "bomb" radiocarbon

    Energy Technology Data Exchange (ETDEWEB)

    Fallon, S; Guilderson, T

    2004-06-30

    Coralline sponges have the potential to fill in gaps in our understanding of subsurface oceanographic variability. However, one disadvantage they have compared to hermatypic reef building coral proxies is that they do not have annual density bands and need to be radiometrically dated for an age determination. To elucidate growth rate variability we have measured radiocarbon in 1 mm increments from Astrosclera willeyana sponges collected off the Central and Northern Great Barrier Reef (GBR) and from Truk in the Caroline Islands and compared these radiocarbon profiles to independently dated coral radiocarbon records. Growth rates of the GBR sponges average 1.2 {+-} 0.3 and 1.0 {+-} 0.3 mm yr{sup -1}, north and central respectively but can vary by a factor of two. The growth rate of the Truk sponge averages 1.2 {+-} 0.1 mm yr{sup -1}. These growth rates are significantly faster to those measured for other GBR Astrosclera willeyana sponges (0.2 mm yr{sup -1}) by Calcein staining (Woerheide 1988).

  10. Short-term effects of supernova explosions on radiocarbon production

    Energy Technology Data Exchange (ETDEWEB)

    Povinec, P. (Komenskeho Univ., Bratislava (Czechoslovakia). Prirodovedecka Fakulta)

    1980-01-01

    The short-term increase in cosmic ray intensity caused by a supernova gamma-ray burst as well as the long-term increase resulting from corpuscular particles accelerated during the supernova explosion may be investigated by cosmogenic radiocarbon. It is shown that o.alactic supernovae exploding at distances up to 1 kpc from the Earth could cause a measurable increase in radiocarbon concentration in the past. Radiocarbon measurements for the period of the Tycho de Brahe supernova showed negative results.

  11. Accelerator Mass Spectrometric determination of radiocarbon in stratospheric CO2, retrieved from AirCore sampling.

    Science.gov (United States)

    Paul, Dipayan; Been, Henk A.; Chen, Huilin; Kivi, Rigel; Meijer, Harro A. J.

    2015-04-01

    In this decade, understanding the impact of human activities on climate is one of the key issues of discussion globally. The continuous rise in the concentration of greenhouse gases, e.g., CO2, CH4, etc. in the atmosphere, predominantly due to human activities, is alarming and requires continuous monitoring to understand the dynamics. Radiocarbon is an important atmospheric tracer and one of the many used in the understanding of the global carbon budget, which includes the greenhouse gases like CO2 and CH4. Measurement of 14C (or radiocarbon) in atmospheric CO2 generally requires collection of large air samples (few liters) from which CO2 is extracted and then the concentration of radiocarbon is determined. Currently, Accelerator Mass Spectrometry (AMS) is the most precise, reliable and widely used technique for atmospheric radiocarbon detection. However, the regular collection of air samples from troposphere and stratosphere, for example using aircraft, is prohibitively expensive. AirCore is an innovative atmospheric sampling system, developed by NOAA. It comprises of a long tube descending from a high altitude with one end open and the other closed, and has been demonstrated to be a reliable, cost-effective sampling system for high-altitude profile (up to ~ 30 km) measurements of CH4and CO2(Karion et al. 2010). In Europe, AirCore measurements are being performed on a regular basis near Sodankylä since September 2013. Here we describe the analysis of two such AirCore samples collected in July 2014, Finland, for determining the 14C concentration in stratospheric CO2. The two AirCore samples were collected on consecutive days. Each stratospheric AirCore sample was divided into six fractions, each containing ~ 35 μg CO2 (~9.5 μg C). Each fraction was separately trapped in 1 /4 inch coiled stainless steel tubing for radiocarbon measurements. The procedure for CO2 extraction from the stratospheric air samples; the sample preparation, with samples containing < 10

  12. Constraining the Late Pleistocene history of the Laurentide Ice Sheet by dating the Missinaibi Formation, Hudson Bay Lowlands, Canada

    Science.gov (United States)

    Dalton, April S.; Finkelstein, Sarah A.; Barnett, Peter J.; Forman, Steven L.

    2016-08-01

    Well-dated paleorecords from periods prior to the Last Glacial Maximum (LGM) are important for validating models of ice sheet build-up and growth. However, owing to glacial erosion, most Late Pleistocene records lie outside of the previously glaciated region, which limits their ability to inform about the dynamics of paleo-ice sheets. Here, we evaluate new and previously published chronology data from the Missinaibi Formation, a Pleistocene-aged deposit in the Hudson Bay Lowlands (HBL), Canada, located near the geographic center of the Laurentide Ice Sheet (LIS). Available radiocarbon (AMS = 44, conventional = 36), amino acid (n = 13), uranium-thorium (U-Th, n = 14), thermoluminescence (TL, n = 15) and optically stimulated luminescence (OSL, n = 5) data suggest that an ice-free HBL may have been possible during parts of Marine Isotope Stage 7 (MIS 7; ca. 243,000 to ca. 190,000 yr BP), MIS 5 (ca. 130,000 to ca. 71,000 yr BP) and MIS 3 (ca. 29,000 to ca. 57,000). While MIS 7 and MIS 5 are well-documented interglacial periods, the development of peat, forest bed and fluvial deposits dating to MIS 3 (n = 20 radiocarbon dates; 4 TL dates, 3 OSL dates), suggests that the LIS retreated and remained beyond, or somewhere within, the boundaries of the HBL during this interstadial. Ice sheet models approximate the margin of the LIS to Southern Ontario during this time, which is 700 km south of the HBL. Therefore, if correct, our data help constrain a significantly different configuration and dynamicity for the LIS than previously modelled. We can find no chronological basis to discount the MIS 3 age assignments. However, since most data originate from radiocarbon dates lying close to the reliable limit of this geochronometer, future work on dating the Missinaibi Formation using other geochronological methods (e.g. U-Th, OSL) is necessary in order to confirm the age estimates and strengthen the boundaries of the LIS during this period.

  13. The 3.6 ka Aniakchak tephra in the Arctic Ocean: a constraint on the Holocene radiocarbon reservoir age in the Chukchi Sea

    DEFF Research Database (Denmark)

    Pearce, C.; Varhelyi, A.; Wastegård, S.

    2016-01-01

    to ice rafting as an important secondary transport mechanism of volcanic ash. Combined with radiocarbon dates on mollusks in the same sediment core, the volcanic marker is used to calculate a marine radiocarbon reservoir age offset ΔR = 477 ± 60 years. This relatively high value may be explained...... and Greenland. This large geographic distribution combined with the fact that the eruption is relatively well constrained in time using radiocarbon dating of lake sediments and annual layer counts in ice cores, makes it an excellent stratigraphic marker for dating and correlating mid – late Holocene sediment...... reservoir age offset, is the first of its kind in the Arctic Ocean and provides an important framework for improving chronologies and correlating marine sediment archives in this region. Core 2PC has a high sediment accumulation rate averaging 200 cm/kyr throughout the last 4000 years, and the chronology...

  14. Eye lens radiocarbon reveals centuries of longevity in the Greenland shark (Somniosus microcephalus)

    DEFF Research Database (Denmark)

    Nielsen, Julius; Hedeholm, Rasmus B; Heinemeier, Jan;

    2016-01-01

    The Greenland shark (Somniosus microcephalus), an iconic species of the Arctic Seas, grows slowly and reaches >500 centimeters (cm) in total length, suggesting a life span well beyond those of other vertebrates. Radiocarbon dating of eye lens nuclei from 28 female Greenland sharks (81 to 502 cm...... in total length) revealed a life span of at least 272 years. Only the smallest sharks (220 cm or less) showed signs of the radiocarbon bomb pulse, a time marker of the early 1960s. The age ranges of prebomb sharks (reported as midpoint and extent of the 95.4% probability range) revealed the age at sexual...... maturity to be at least 156 ± 22 years, and the largest animal (502 cm) to be 392 ± 120 years old. Our results show that the Greenland shark is the longest-lived vertebrate known, and they raise concerns about species conservation....

  15. Eye lens radiocarbon reveals centuries of longevity in the Greenland shark (Somniosus microcephalus).

    Science.gov (United States)

    Nielsen, Julius; Hedeholm, Rasmus B; Heinemeier, Jan; Bushnell, Peter G; Christiansen, Jørgen S; Olsen, Jesper; Ramsey, Christopher Bronk; Brill, Richard W; Simon, Malene; Steffensen, Kirstine F; Steffensen, John F

    2016-08-12

    The Greenland shark (Somniosus microcephalus), an iconic species of the Arctic Seas, grows slowly and reaches >500 centimeters (cm) in total length, suggesting a life span well beyond those of other vertebrates. Radiocarbon dating of eye lens nuclei from 28 female Greenland sharks (81 to 502 cm in total length) revealed a life span of at least 272 years. Only the smallest sharks (220 cm or less) showed signs of the radiocarbon bomb pulse, a time marker of the early 1960s. The age ranges of prebomb sharks (reported as midpoint and extent of the 95.4% probability range) revealed the age at sexual maturity to be at least 156 ± 22 years, and the largest animal (502 cm) to be 392 ± 120 years old. Our results show that the Greenland shark is the longest-lived vertebrate known, and they raise concerns about species conservation.

  16. 31 CFR 560.301 - Effective date.

    Science.gov (United States)

    2010-07-01

    ... 31 Money and Finance: Treasury 3 2010-07-01 2010-07-01 false Effective date. 560.301 Section 560... § 560.301 Effective date. The effective date of the prohibitions and directives contained in subpart B of this part is 12:01 a.m., Eastern Daylight Time, August 20, 1997. For the effective date of...

  17. Nauru Island Radiocarbon Data for 1994 to 1995

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Nauru-2 coral radiocarbon (14C) timeseries. (166E, 0.5S, 14m bottom depth). Coral radiocarbon (Delta-14C) on untreated, low-speed drilled samples. Precision is +/- 4...

  18. New radiocarbon chronology of a late Holocene landslide event in the Mont Blanc massif, Italy

    Science.gov (United States)

    Hajdas, Irka; Sojc, Ursula; Ivy-Ochs, Susan; Akçar, Naki; Deline, Philip

    2016-04-01

    The Ferret valley Arp Nouva peat bog located in the Mont Blanc massif was critically evaluated since previously published radiocarbon dates have led to controversial conclusions on the formation of the swamp. Radiocarbon dating of roots from three pits of up to 1 m depth was applied to discuss the question whether the historical documented rock avalanche occurring in AD 1717 overran the peat bog or formed it at a later stage. Our results indicate that the rock avalanche formed the Arp Nouva peat bog by downstream blockage of the Bellecombe torrent. Furthermore, careful sample preparation with consequent separation of roots from the bulk peat sample provides possible explanation for the too old 14C ages of bulk peat samples dated previously (Deline and Kirkbride, 2009 and references therein). This work demonstrates that a combined geomorphological and geochronological approach is the most reliable way to reconstruct landscape evolution, especially in light of apparent chronological problems. The key to successful 14C dating is a careful sample selection and the identification of material that might be not ideal for chronological reconstructions. References Deline, Philip, and Martin P. Kirkbride. "Rock avalanches on a glacier and morainic complex in Haut Val Ferret (Mont Blanc Massif, Italy)".Geomorphology 103 (2009): 80-92.

  19. Radiocarbon analyses along the EDML ice core in Antarctica

    Energy Technology Data Exchange (ETDEWEB)

    Wal, R.S.W. van de; Veen, C. van der [Utrecht Univ. (Netherlands). Inst. for Marine and Atmospheric research; Meijer, H.A.J.; De Rooij, M. [Univ. of Groningen (Netherlands). Center for Isotope Research

    2007-02-15

    Samples, 17 in total, from the EDML core drilled at Kohnen station Antarctica are analysed for {sup 14}CO and {sup 14}CO{sub 2} with a dry-extraction technique in combination with accelerator mass spectrometry. Results of the in situ produced {sup 14}CO fraction show a very low concentration of in situ produced {sup 14}CO. Despite these low levels in carbon monoxide, a significant in situ production is observed in the carbon dioxide fraction. For the first time we found background values for the ice samples which are equal to line blanks. The data set is used to test a model for the production of {sup 14}C in the ice matrix, in combination with a degassing as {sup 14}CO{sub 2} and possibly as {sup 14}CO into the air bubbles. Application of the model, for which no independent validation is yet possible, offers the opportunity to use radiocarbon analysis as dating technique for the air bubbles in the ice. Assigning an arbitrary error of 25% to the calculation of the in situ production leads to age estimates, after correction for the in situ production, which are in agreement with age estimates based on a volcanic layer match of EDML to the Dome C timescale in combination with a correction for firn diffusion.

  20. SECOND RADIOCARBON INTERCOMPARISON PROGRAM FOR THE CHAUVET-PONT D'ARC CAVE, ARDECHE, FRANCE

    NARCIS (Netherlands)

    Quiles, A.; Valladas, H.; Geneste, J-M; Clottes, J.; Baffier, D.; Berthier, B.; Brock, F.; Ramsey, C. Bronk; Delque-Kolic, E.; Dumoulin, J-P; Hajdas, I.; Hippe, K.; Hodgins, G. W. L.; Hogg, A.; Jull, A. J. T.; Kaltnecker, E.; de Martino, M.; Oberlin, C.; Petchey, F.; Steier, P.; Synal, H-A; van der Plicht, J.; Wild, E. M.; Zazzo, A.

    2014-01-01

    The Chauvet-Pont d'Arc Cave is one of the most important sites for the study of the earliest manifestations and development of prehistoric art at the beginning of the Upper Paleolithic. Different dating techniques have been performed thus far (AMS C-14, U/Th TIMS, Cl-36 dating) to model the chronolo

  1. Integrated Tree-Ring-Radiocarbon High-Resolution Timeframe to Resolve Earlier Second Millennium BCE Mesopotamian Chronology

    Science.gov (United States)

    Griggs, Carol B.; Lorentzen, Brita; Barjamovic, Gojko; Ramsey, Christopher Bronk; Kromer, Bernd; Wild, Eva Maria

    2016-01-01

    500 years of ancient Near Eastern history from the earlier second millennium BCE, including such pivotal figures as Hammurabi of Babylon, Šamši-Adad I (who conquered Aššur) and Zimrilim of Mari, has long floated in calendar time subject to rival chronological schemes up to 150+ years apart. Texts preserved on clay tablets provide much information, including some astronomical references, but despite 100+ years of scholarly effort, chronological resolution has proved impossible. Documents linked with specific Assyrian officials and rulers have been found and associated with archaeological wood samples at Kültepe and Acemhöyük in Turkey, and offer the potential to resolve this long-running problem. Here we show that previous work using tree-ring dating to place these timbers in absolute time has fundamental problems with key dendrochronological crossdates due to small sample numbers in overlapping years and insufficient critical assessment. To address, we have integrated secure dendrochronological sequences directly with radiocarbon (14C) measurements to achieve tightly resolved absolute (calendar) chronological associations and identify the secure links of this tree-ring chronology with the archaeological-historical evidence. The revised tree-ring-sequenced 14C time-series for Kültepe and Acemhöyük is compatible only with the so-called Middle Chronology and not with the rival High, Low or New Chronologies. This finding provides a robust resolution to a century of uncertainty in Mesopotamian chronology and scholarship, and a secure basis for construction of a coherent timeframe and history across the Near East and East Mediterranean in the earlier second millennium BCE. Our re-dating also affects an unusual tree-ring growth anomaly in wood from Porsuk, Turkey, previously tentatively associated with the Minoan eruption of the Santorini volcano. This tree-ring growth anomaly is now directly dated ~1681–1673 BCE (68.2% highest posterior density range), ~20

  2. Integrated Tree-Ring-Radiocarbon High-Resolution Timeframe to Resolve Earlier Second Millennium BCE Mesopotamian Chronology.

    Science.gov (United States)

    Manning, Sturt W; Griggs, Carol B; Lorentzen, Brita; Barjamovic, Gojko; Ramsey, Christopher Bronk; Kromer, Bernd; Wild, Eva Maria

    2016-01-01

    500 years of ancient Near Eastern history from the earlier second millennium BCE, including such pivotal figures as Hammurabi of Babylon, Šamši-Adad I (who conquered Aššur) and Zimrilim of Mari, has long floated in calendar time subject to rival chronological schemes up to 150+ years apart. Texts preserved on clay tablets provide much information, including some astronomical references, but despite 100+ years of scholarly effort, chronological resolution has proved impossible. Documents linked with specific Assyrian officials and rulers have been found and associated with archaeological wood samples at Kültepe and Acemhöyük in Turkey, and offer the potential to resolve this long-running problem. Here we show that previous work using tree-ring dating to place these timbers in absolute time has fundamental problems with key dendrochronological crossdates due to small sample numbers in overlapping years and insufficient critical assessment. To address, we have integrated secure dendrochronological sequences directly with radiocarbon (14C) measurements to achieve tightly resolved absolute (calendar) chronological associations and identify the secure links of this tree-ring chronology with the archaeological-historical evidence. The revised tree-ring-sequenced 14C time-series for Kültepe and Acemhöyük is compatible only with the so-called Middle Chronology and not with the rival High, Low or New Chronologies. This finding provides a robust resolution to a century of uncertainty in Mesopotamian chronology and scholarship, and a secure basis for construction of a coherent timeframe and history across the Near East and East Mediterranean in the earlier second millennium BCE. Our re-dating also affects an unusual tree-ring growth anomaly in wood from Porsuk, Turkey, previously tentatively associated with the Minoan eruption of the Santorini volcano. This tree-ring growth anomaly is now directly dated ~1681-1673 BCE (68.2% highest posterior density range), ~20

  3. Integrated Tree-Ring-Radiocarbon High-Resolution Timeframe to Resolve Earlier Second Millennium BCE Mesopotamian Chronology.

    Directory of Open Access Journals (Sweden)

    Sturt W Manning

    Full Text Available 500 years of ancient Near Eastern history from the earlier second millennium BCE, including such pivotal figures as Hammurabi of Babylon, Šamši-Adad I (who conquered Aššur and Zimrilim of Mari, has long floated in calendar time subject to rival chronological schemes up to 150+ years apart. Texts preserved on clay tablets provide much information, including some astronomical references, but despite 100+ years of scholarly effort, chronological resolution has proved impossible. Documents linked with specific Assyrian officials and rulers have been found and associated with archaeological wood samples at Kültepe and Acemhöyük in Turkey, and offer the potential to resolve this long-running problem. Here we show that previous work using tree-ring dating to place these timbers in absolute time has fundamental problems with key dendrochronological crossdates due to small sample numbers in overlapping years and insufficient critical assessment. To address, we have integrated secure dendrochronological sequences directly with radiocarbon (14C measurements to achieve tightly resolved absolute (calendar chronological associations and identify the secure links of this tree-ring chronology with the archaeological-historical evidence. The revised tree-ring-sequenced 14C time-series for Kültepe and Acemhöyük is compatible only with the so-called Middle Chronology and not with the rival High, Low or New Chronologies. This finding provides a robust resolution to a century of uncertainty in Mesopotamian chronology and scholarship, and a secure basis for construction of a coherent timeframe and history across the Near East and East Mediterranean in the earlier second millennium BCE. Our re-dating also affects an unusual tree-ring growth anomaly in wood from Porsuk, Turkey, previously tentatively associated with the Minoan eruption of the Santorini volcano. This tree-ring growth anomaly is now directly dated ~1681-1673 BCE (68.2% highest posterior density

  4. Pego do Diabo (Loures, Portugal: dating the emergence of anatomical modernity in westernmost Eurasia.

    Directory of Open Access Journals (Sweden)

    João Zilhão

    Full Text Available BACKGROUND: Neandertals and the Middle Paleolithic persisted in the Iberian Peninsula south of the Ebro drainage system for several millennia beyond their assimilation/replacement elsewhere in Europe. As only modern humans are associated with the later stages of the Aurignacian, the duration of this persistence pattern can be assessed via the dating of diagnostic occurrences of such stages. METHODOLOGY/PRINCIPAL FINDINGS: Using AMS radiocarbon and advanced pretreatment techniques, we dated a set of stratigraphically associated faunal samples from an Aurignacian III-IV context excavated at the Portuguese cave site of Pego do Diabo. Our results establish a secure terminus ante quem of ca. 34,500 calendar years ago for the assimilation/replacement process in westernmost Eurasia. Combined with the chronology of the regional Late Mousterian and with less precise dating evidence for the Aurignacian II, they place the denouement of that process in the 37th millennium before present. CONCLUSIONS/SIGNIFICANCE: These findings have implications for the understanding of the emergence of anatomical modernity in the Old World as a whole, support explanations of the archaic features of the Lagar Velho child's anatomy that invoke evolutionarily significant Neandertal/modern admixture at the time of contact, and counter suggestions that Neandertals could have survived in southwest Iberia until as late as the Last Glacial Maximum.

  5. Radiocarbon Age Variability of Deep Sea Corals from the North Atlantic and the Southern Ocean

    Science.gov (United States)

    Thiagarajan, N.; Gerlach, D. S.; Roberts, M.; McNichol, A. P.; Thresher, R.; Adkins, J. F.

    2009-12-01

    Deep-sea corals are a relatively new and unique archive in paleoceanography. They have large banded unbioturbated skeletons that allow for high resolution records. They also have a high uranium content allowing for accurate calendar ages independent of radiocarbon age measurements. One problem of using deep-sea corals for long records is that it is difficult to date a large numbers of corals accurately and precisely. Unlike sediment cores, fossil fields have no inherent stratigraphy and each coral must be separately dated. Here we present the results of ‘reconnaissance radiocarbon age analyses’ made at NOSAMS on Desmophyllum Dianthus (D. Dianthus) collected from the New England Seamounts and South of Tasmania. Reconnaissance radiocarbon age analyses are much more rapid compared to traditional hydrolysis methods allowing for many more corals to be dated. The corals dated with the reconnaissance method yielded similar ages as corals analyzed with the traditional hydrolysis method within 1σ error. A single coral with multiple measurements (n=9) yielded a standard error of 59 years. We report 14C ages of 228 D. Dianthus of 5000 fossil D. Dianthus collected from the New England Seamounts (32-42N, 46-70W, 1188-2546 m). Similar to earlier results (Robinson et al, 2007), we find that coral populations migrate both in depth and across the seamount chain through time. During periods of rapid climate change events (Heinrich Events and Younger Dryas), the coral population spreads through the water column and across the seamount chain. However, during the Holocene, the coral population migrates to shallower depths of less than 1250m. During the LGM, the coral population retreats to a restricted depth range of 1500-2000m. We also find that the coral population expanded during the Little Ice Age, a result missed with the smaller sample set. We also will present the result of 250 radiocarbon analyses, from a collection of over 9000 fossil D. dianthus, from the Tasman sea (44

  6. Eye lens radiocarbon reveals centuries of longevity in the Greenland shark (Somniosus microcephalus)

    DEFF Research Database (Denmark)

    Nielsen, Julius; Hedeholm, Rasmus B.; Heinemeier, Jan

    2016-01-01

    The Greenland shark (Somniosus microcephalus), an iconic species of the Arctic Seas, grows slowly and reaches >500 centimeters (cm) in total length, suggesting a life span well beyond those of other vertebrates. Radiocarbon dating of eye lens nuclei from 28 female Greenland sharks (81 to 502 cm...... maturity to be at least 156 ± 22 years, and the largest animal (502 cm) to be 392 ± 120 years old. Our results show that the Greenland shark is the longest-lived vertebrate known, and they raise concerns about species conservation....

  7. Suggested terminology for Quaternary dating methods

    Science.gov (United States)

    Colman, Steven M.; Pierce, K.L.; Birkeland, P.W.

    1987-01-01

    Classification of Quaternary dating methods should be based on the level of quantitative information and the degree of confidence contained in the age estimates produced by the dating methods. We recommend the use of the terms numerical-age, calibrated-age, relative-age, and correlated-age to describe these levels. We also classify dating methods by type into sideral, isotopic, radiogenic, chemical and biological, geomorphic, and correlation methods. The use of "absolute" is inappropriate for most dating methods, and should be replaced by "numerical." The use of "date" should be minimized in favor of "age" or "age estimate." We recommend use of the abbreviations ka and Ma for most ages; calender dates can be used where appropriate and yr B.P. can be used for radiocarbon ages. ?? 1987.

  8. Application of Bomb Radiocarbon Chronologies to Shortfin Mako (Isurus oxyrinchus)

    Energy Technology Data Exchange (ETDEWEB)

    Ardizzone, D; Cailliet, G M; Natanson, L J; Andrews, A H; Kerr, L A; Brown, T A

    2007-07-16

    and the number of samples for MIA analysis was insufficient for some months. Hence, unequivocal validation of shortfin mako age estimates has yet to be accomplished. Atmospheric testing of thermonuclear devices in the 1950s and 1960s effectively doubled the natural atmospheric radiocarbon ({sup 14}C). The elevated {sup 14}C levels were first recorded in 1957-58, with a peak around 1963. As a consequence, {sup 14}C entered the ocean through gas exchange with the atmosphere at the ocean surface and in terrestrial runoff. Despite variable oceanographic conditions, a worldwide rise of the bomb {sup 14}C signal entered the ocean mixed layer as dissolved inorganic carbon (DIC) in 1957-58. The large amounts of {sup 14}C released from the bomb tests produced a signature that can be followed through time, throughout the marine food web, and into deeper waters. The marked increase of radiocarbon levels was first measured in the DIC of seawater and in biogenic marine carbonates of hermatypic corals in Florida. Subsequently, this record was documented in corals from other regions and in the thallus of rhodoliths. The accumulation of radiocarbon in the hard parts of most marine organisms in the mixed layer (such as fish otoliths and bivalves) was synchronous with the coral time-series. This technique has been used to validate age estimates and longevity of numerous bony fishes to date, as well as to establish bomb radiocarbon chronologies from different oceans. In the first application of this technique to lamnoid sharks, validated annual band-pair deposition in vertebral growth bands for the porbeagle (Lamna nasus) aged up to 26 years. Radiocarbon values from samples obtained from 15 porbeagle caught in the western North Atlantic Ocean (some of which were known-age) produced a chronology similar in magnitude to the reference carbonate chronology for that region. The observed phase shift of about 3 years was attributed to different sources of carbon between vertebrae and those for

  9. Dating Violence

    Science.gov (United States)

    Stader, David L.

    2011-01-01

    Dating violence is a form of student-on-student victimization and is a serious school safety issue. Research indicates that at a minimum, 10 percent of high school students are victims of dating violence in one form or another. Among female high school students that date, some data indicate that as many as 30 percent may be victims of dating…

  10. Optimization of simultaneous tritium-radiocarbon internal gas proportional counting

    Science.gov (United States)

    Bonicalzi, R. M.; Aalseth, C. E.; Day, A. R.; Hoppe, E. W.; Mace, E. K.; Moran, J. J.; Overman, C. T.; Panisko, M. E.; Seifert, A.

    2016-03-01

    Specific environmental applications can benefit from dual tritium and radiocarbon measurements in a single compound. Assuming typical environmental levels, it is often the low tritium activity relative to the higher radiocarbon activity that limits the dual measurement. In this paper, we explore the parameter space for a combined tritium and radiocarbon measurement using a natural methane sample mixed with an argon fill gas in low-background proportional counters of a specific design. We present an optimized methane percentage, detector fill pressure, and analysis energy windows to maximize measurement sensitivity while minimizing count time. The final optimized method uses a 9-atm fill of P35 (35% methane, 65% argon), and a tritium analysis window from 1.5 to 10.3 keV, which stops short of the tritium beta decay endpoint energy of 18.6 keV. This method optimizes tritium-counting efficiency while minimizing radiocarbon beta-decay interference.

  11. AMS/DOE Fellowship Recipients

    Energy Technology Data Exchange (ETDEWEB)

    Armstrong, Stephanie [American Meteorological Society, Boston, MA (United States)

    2016-11-21

    The AMS/DOE graduate fellowships were awarded to three students entering their first year of graduate study. The funds allowed each student to take a full course load during their first of year of graduate study which helps each of them to enter the professional, scientific community at an earlier date. Each recipient is academically outstanding, received glowing references of support and demonstrated their strong desire to perform scientific research. As part of the fellowship, each of the students was invited to attend the AMS Annual Meeting where they got to participate in the AMS student conference, attend scientific sessions and visit the exhibition hall. In addition, a student awards luncheon was held where each of the recipients got to meet their sponsor and receive a certificate.

  12. The 14C-AMS Laboratory at IF-UFF

    Energy Technology Data Exchange (ETDEWEB)

    Macario, K.D.; Gomes, P.R.S.; Anjos, R.M.; Linares, R.; Carvalho, C.R.A.; Castro, M.D.; Oliveira, F.M.; Alves, E.Q.; Chanca, I.S. [Universidade Federal Fluminense (UFF), Niteroi, RJ (Brazil)

    2012-07-01

    Full text: In 2009 a radiocarbon sample preparation laboratory dedicated to Accelerator Mass Spectrometry was installed at the Physics Institute of the Fluminense Federal University. At the Radiocarbon Laboratory samples of several kinds of materials such as charcoal, sediments, wood and shells go through specific chemical treatment and conversion to carbon dioxide. Graphite reduction is performed in sealed Pyrex tubes, using Zinc, Titanium Hydrate, and iron catalyst within an inner tube. Samples have been successfully produced yielding fluffy homogeneous graphite leading to high and stable currents in the ion source. For sample measurement an accelerator system produced by the National Electrostatics Corporation (NEC), was installed in the Physics Institute. The machine, specially developed to carbon analysis, is the State of the Art in 14C - AMS studies and its acquisition represent a very important step for Brazil towards the development of science and technology regarding radiocarbon studies. The system includes an open air deck 250 kV single stage electrostatic accelerator with magnetic and electrostatic analyzers that enable isotope separation and detection. Radiocarbon concentrations are measured to 1 part in 10{sup 15} with precision of 0.3 The Nuclear Applied Physics group on Chronological Studies is now performing multidisciplinary research in collaboration with Brazilian and foreign groups from several fields of science such as Archaeology, Geophysics, Oceanography and Biology, in studies on the evolution of marine, terrestrial and Antarctic ecosystems. (author)

  13. Reconciling radiocarbon and ice core timescales over the Holocene - Cosmogenic radionuclides as synchronization tools

    Science.gov (United States)

    Muscheler, R.; Adolphi, F.; Mekhaldi, F.

    2015-12-01

    The atmospheric production rates of cosmogenic radionuclides, such as 14C and 10Be, vary globally due to external processes, namely the solar and geomagnetic modulation of the galactic cosmic ray flux as well as solar proton events. This signature is recorded in various archives such as ice cores (10Be) and tree-rings (14C). Hence, cosmogenic radionuclides offer a means to continuously assess timescale differences between two of the most widely used timescales in paleoclimatology - the radiocarbon and the ice core timescales. Short lived solar proton events additionally provide distinct marker horizons that allow synchronization of discrete horizons at annual precision. We will present a cosmogenic radionuclide based synchronization of the Greenland ice core timescale (GICC05, Svensson et al., 2008) and the radiocarbon timescale (IntCal13, Reimer et al., 2013) over the Holocene. This synchronization allows radiocarbon dated and ice core paleoclimate records to be compared on a common timescale at down to sub-decadal precision. We will compare these results to independent discrete isochrones obtained from tephrochronology and solar proton events. In addition, we will discuss implications for the accuracy and uncertainty estimates of GICC05 over the Holocene. Reimer, P. J., Bard, E., Bayliss, A., Beck, J. W., Blackwell, P. G., Bronk Ramsey, C., Buck, C. E., Cheng, H., Edwards, R. L., Friedrich, M., Grootes, P. M., Guilderson, T. P., Haflidason, H., Hajdas, I., Hatté, C., Heaton, T. J., Hoffmann, D. L., Hogg, A. G., Hughen, K. A., Kaiser, K. F., Kromer, B., Manning, S. W., Niu, M., Reimer, R. W., Richards, D. A., Scott, E. M., Southon, J. R., Staff, R. A., Turney, C. S. M., and van der Plicht, J.: IntCal13 and Marine13 Radiocarbon Age Calibration Curves 0-50,000 Years cal BP, Radiocarbon, 55, 1869-1887, 10.2458/azu_js_rc.55.16947, 2013. Svensson, A., Andersen, K. K., Bigler, M., Clausen, H. B., Dahl-Jensen, D., Davies, S. M., Johnsen, S. J., Muscheler, R., Parrenin

  14. Refining 14C dating of bone >30,000 BP : establishing an accurate chronology for the Middle to Upper Palaeolithic transition in France.

    NARCIS (Netherlands)

    Talamo, Sahra

    2012-01-01

    This thesis aims to improve the chronology of the transition from the Middle to Upper Palaeolithic in France through the radiocarbon dating of bone collagen samples. This requires accurate calibration of the radiocarbon time scale for this time interval, reliable extraction of collagen from prehisto

  15. Southern Appalachian hillslope erosion rates measured by soil and detrital radiocarbon in hollows

    Science.gov (United States)

    Hales, T.C.; Scharer, K.M.; Wooten, R.M.

    2012-01-01

    Understanding the dynamics of sediment generation and transport on hillslopes provides important constraints on the rate of sediment output from orogenic systems. Hillslope sediment fluxes are recorded by organic material found in the deposits infilling unchanneled convergent topographic features called hollows. This study describes the first hollow infilling rates measured in the southern Appalachian Mountains. Infilling rates (and bedrock erosion rates) were calculated from the vertical distribution of radiocarbon ages at two sites in the Coweeta drainage basin, western North Carolina. At each site we dated paired charcoal and silt soil organic matter samples from five different horizons. Paired radiocarbon samples were used to bracket the age of the soil material in order to capture the range of complex soil forming processes and deposition within the hollows. These dates constrain hillslope erosion rates of between 0.051 and 0.111mmyr-1. These rates are up to 4 times higher than spatially-averaged rates for the Southern Appalachian Mountains making creep processes one of the most efficient erosional mechanisms in this mountain range. Our hillslope erosion rates are consistent with those of forested mountain ranges in the western United States, suggesting that the mechanisms (dominantly tree throw) driving creep erosion in both the western United States and the Southern Appalachian Mountains are equally effective. ?? 2011 Elsevier B.V.

  16. Searching for the oldest baobab of Madagascar: radiocarbon investigation of large Adansonia rubrostipa trees.

    Science.gov (United States)

    Patrut, Adrian; von Reden, Karl F; Danthu, Pascal; Pock-Tsy, Jean-Michel Leong; Patrut, Roxana T; Lowy, Daniel A

    2015-01-01

    We extended our research on the architecture, growth and age of trees belonging to the genus Adansonia, by starting to investigate large individuals of the most widespread Malagasy species. Our research also intends to identify the oldest baobabs of Madagascar. Here we present results of the radiocarbon investigation of the two most representative Adansonia rubrostipa (fony baobab) specimens, which are located in south-western Madagascar, in the Tsimanampetsotse National Park. We found that the fony baobab called "Grandmother" consists of 3 perfectly fused stems of different ages. The radiocarbon date of the oldest sample was found to be 1136 ± 16 BP. We estimated that the oldest part of this tree, which is mainly hollow, has an age close to 1,600 yr. This value is comparable to the age of the oldest Adansonia digitata (African baobab) specimens. By its age, the Grandmother is a major candidate for the oldest baobab of Madagascar. The second investigated specimen, called the "polygamous baobab", consists of 6 partially fused stems of different ages. According to dating results, this fony baobab is 1,000 yr old. This research is the first investigation of the structure and age of Malagasy baobabs.

  17. Searching for the oldest baobab of Madagascar: radiocarbon investigation of large Adansonia rubrostipa trees.

    Directory of Open Access Journals (Sweden)

    Adrian Patrut

    Full Text Available We extended our research on the architecture, growth and age of trees belonging to the genus Adansonia, by starting to investigate large individuals of the most widespread Malagasy species. Our research also intends to identify the oldest baobabs of Madagascar. Here we present results of the radiocarbon investigation of the two most representative Adansonia rubrostipa (fony baobab specimens, which are located in south-western Madagascar, in the Tsimanampetsotse National Park. We found that the fony baobab called "Grandmother" consists of 3 perfectly fused stems of different ages. The radiocarbon date of the oldest sample was found to be 1136 ± 16 BP. We estimated that the oldest part of this tree, which is mainly hollow, has an age close to 1,600 yr. This value is comparable to the age of the oldest Adansonia digitata (African baobab specimens. By its age, the Grandmother is a major candidate for the oldest baobab of Madagascar. The second investigated specimen, called the "polygamous baobab", consists of 6 partially fused stems of different ages. According to dating results, this fony baobab is 1,000 yr old. This research is the first investigation of the structure and age of Malagasy baobabs.

  18. The new AMS system at CEDAD for the analysis of {sup 10}Be, {sup 26}Al, {sup 129}I and actinides: Set-up and performances

    Energy Technology Data Exchange (ETDEWEB)

    Calcagnile, Lucio, E-mail: lucio.calcagnile@unisalento.it [CEDAD (Centre for Dating and Diagnostics), Department of Engineering for Innovation, University of Salento (Italy); Quarta, Gianluca; Maruccio, Lucio [CEDAD (Centre for Dating and Diagnostics), Department of Engineering for Innovation, University of Salento (Italy); Synal, Hans-Arno; Müller, Arnold Milenko [Laboratory of Ion Beam Physics, ETH Zurich, 8093 Zurich (Switzerland)

    2015-10-15

    The Centre for Dating and Diagnostics (CEDAD) at the University of Salento was established in 2001 and became fully operational for routine {sup 14}C radiocarbon dating in 2003. The facility has been continuously upgraded over the years with the installation of different beam lines for high energy ion implantation, IBA analyses both in vacuum and in air and nuclear microprobe. In 2011 a second AMS beamline was installed consisting of a dedicated high energy mass spectrometer for the AMS analysis of rare nuclides such as {sup 10}Be, {sup 26}Al, {sup 129}I and actinides. First tests on {sup 10}Be allowed to optimize the operating parameters resulting in the proper separation of {sup 10}Be from the interfering isobar {sup 10}B. In this paper we present the further tests and optimizations which resulted in an enhancement of the overall transmission efficiency, the reduction of the background (in the 10{sup −15} range) and in the possibility to obtain precision levels in routine {sup 10}Be/{sup 9}Be measurements of the order of 0.5%. Furthermore the first results obtained for the analysis of {sup 26}Al and {sup 129}I are also presented.

  19. Bomb-spike dating of a mummified baboon in Ludwig Cave, Namibia

    Directory of Open Access Journals (Sweden)

    Hodgins Greg

    2007-01-01

    Full Text Available In 1982 a mummified adult female baboon was discovered on a ledge in Ludwig Cave in Namibia. A toe bone was removed for dating in July 1995. AMS radiocarbon dating of bone collagen, tendon, and skin indicates a post-modern age. Application of the atomic bomb-spike calibration curve suggests death in late 1977 and an age at death of around 19 years. Baboons roost in the cave and the mummified female, along with a mummified juvenile male discovered in 2002 and three rotting corpses discovered in 1995, were probably chased by other baboons or by leopards down a ca. 6 m drop during the rainy season, and were unable to climb the steep and very slippery slope to escape. The large number of baboons trapped in the cave in less than 20 years, and mummification of two individuals on dry, dusty ledges in the cave, may explain why large numbers of baboon skeletons have been discovered in ancient bone breccias (up to 4 Ma old in a number of caves throughout Southern Africa.

  20. 14C dates from Tel Rehov: Iron-Age chronology, pharaohs, and Hebrew kings.

    Science.gov (United States)

    Bruins, Hendrik J; van der Plicht, Johannes; Mazar, Amihai

    2003-04-11

    Stratified radiocarbon dates provide an independent chronological link between archaeological layers and historical data. The invasion by Pharaoh Shoshenq I (Shishak) is a key historical synchronism, approximately 925 B.C.E., mentioned in both Egyptian inscriptions and the Hebrew Bible. The list of places raided by Shoshenq, mentioned at Karnak (Egypt), includes Rehov (Israel). The site yielded a consistent series of radiocarbon dates from the 12th to 9th century B.C.E. Our results (i) suggest a revised Iron-Age chronology; (ii) date an archaeological stratum to Shoshenq's campaign; (iii) indicate the similarity of "Solomonic" and "Omride" pottery; and (iv) provide correlation with Greece and Cyprus.

  1. Developing inorganic carbon-based radiocarbon chronologies for Holocene lake sediments in arid NW China

    Science.gov (United States)

    Zhang, Jiawu; Ma, Xueyang; Qiang, Mingrui; Huang, Xiaozhong; Li, Shuang; Guo, Xiaoyan; Henderson, Andrew C. G.; Holmes, Jonathan A.; Chen, Fahu

    2016-07-01

    Inorganic carbonates are often used to establish radiocarbon (14C) chronologies for lake sediments when terrestrial plant remains (TPR) are rare or when bulk organic matter is insufficient for dating, a problem that is common for many lakes in arid regions. However, the reservoir effect (RE), as well as old carbon contributed from the lakes catchment make it difficult to establish reliable chronologies. Here we present a systematic study of inorganic 14C ages of two lake-sediment sequences, one from a small-enclosed saline lake - Lake Gahai in Qaidam Basin, and the other from a large freshwater lake - Lake Bosten in Xinjiang. Modern dissolved inorganic carbon (DIC) of the lakes, paleo-lake sediments exposed in the catchment, and mollusk shells in core sediments from Lake Gahai were dated to assess the RE and the contribution of pre-aged carbon to the old ages in the cores. We propose a statistical regression to assess more than one RE for the 14C carbonate ages within our sedimentary sequences. Old radiocarbon ages contributed by detrital carbonates were assessed by comparing the ages of mollusk shells with those of carbonates at the same sediment depths. We established the RE of the authigenic component and assessed detrital old carbon contributions to our two sites, and this was used to correct the 14C ages. Based on this approach, we developed age models for both cores, and tested them using 210Pb ages in both cores and TPR-based 14C-ages recovered from Lake Bosten. We further tested our age models by comparing carbonate-based oxygen isotope (δ18O) records from both lakes to an independently-dated regional speleothem δ18O record. Our results suggest if sedimentary sequences are densely dated and the RE and the contribution of old carbon from detrital carbonates can be ascertained, robust chronological frameworks based on carbonate-based 14C determinations can be established.

  2. Radiocarbon analysis of stratospheric CO2 retrieved from AirCore sampling

    Science.gov (United States)

    Paul, Dipayan; Chen, Huilin; Been, Henk A.; Kivi, Rigel; Meijer, Harro A. J.

    2016-10-01

    Radiocarbon (14C) is an important atmospheric tracer and one of the many used in the understanding of the global carbon budget, which includes the greenhouse gases CO2 and CH4. Measurement of radiocarbon in atmospheric CO2 generally requires the collection of large air samples (a few liters) from which CO2 is extracted and then the concentration of radiocarbon is determined using accelerator mass spectrometry (AMS). However, the regular collection of air samples from the stratosphere, for example using aircraft and balloons, is prohibitively expensive. Here we describe radiocarbon measurements in stratospheric CO2 collected by the AirCore sampling method. AirCore is an innovative atmospheric sampling system, which comprises a long tube descending from a high altitude with one end open and the other closed, and it has been demonstrated to be a reliable, cost-effective sampling system for high-altitude profile (up to ≈ 30 km) measurements of CH4 and CO2. In Europe, AirCore measurements have been being performed on a regular basis near Sodankylä (northern Finland) since September 2013. Here we describe the analysis of samples from two such AirCore flights made there in July 2014, for determining the radiocarbon concentration in stratospheric CO2. The two AirCore profiles were collected on consecutive days. The stratospheric part of the AirCore was divided into six sections, each containing ≈ 35 µg CO2 ( ≈ 9.6 µgC), and stored in a stratospheric air subsampler constructed from 1/4 in. coiled stainless steel tubing ( ≈ 3 m). A small-volume extraction system was constructed that enabled > 99.5 % CO2 extraction from the stratospheric air samples. Additionally, a new small-volume high-efficiency graphitization system was constructed for graphitization of these extracted CO2 samples, which were measured at the Groningen AMS facility. Since the stratospheric samples were very similar in mass, reference samples were also prepared in the same mass range for

  3. Progress on multi-nuclide AMS of JAEA-AMS-TONO

    Energy Technology Data Exchange (ETDEWEB)

    Saito-Kokubu, Yoko, E-mail: kokubu.yoko@jaea.go.jp [Japan Atomic Energy Agency, Toki, Gifu 509-5102 (Japan); Matsubara, Akihiro [Japan Atomic Energy Agency, Toki, Gifu 509-5102 (Japan); Miyake, Masayasu; Nishizawa, Akimitsu; Ohwaki, Yoshio; Nishio, Tomohiro; Sanada, Katsuki [Pesco Corp., Ltd., Toki, Gifu 509-5123 (Japan); Hanaki, Tatsumi [Japan Atomic Energy Agency, Toki, Gifu 509-5102 (Japan)

    2015-10-15

    The JAEA-AMS-TONO (Japan Atomic Energy Agency’s Accelerator Mass Spectrometer established at the Tono Geoscience Center) facility has been used for the dating of geological samples. The AMS system is versatile, based on a 5 MV tandem Pelletron-type accelerator. Since its establishment in 1997, the AMS system has been used for measurement of carbon-14 ({sup 14}C) mainly for {sup 14}C dating studies in neotectonics and hydrogeology, in support of JAEA’s research on geosphere stability applicable to the long-term isolation of high-level radioactive waste. Results of the measurement of {sup 14}C in soils and plants has been applied to the dating of fault activity and volcanism. Development of beryllium-10 ({sup 10}Be) and aluminum-26 ({sup 26}Al) AMS systems are now underway to enhance the capability of the multi-nuclide AMS in studies of dating by cosmogenic nuclides. The {sup 10}Be-AMS system has already been used for routine measurements in applied studies and improvements of the measurement technique have been made. Now we plan to fine tune the system and perform test measurements to develop the {sup 26}Al-AMS system.

  4. Rate of radiocarbon retention onto calcite by isotope exchange

    Energy Technology Data Exchange (ETDEWEB)

    Lempinen, Janne; Lehto, Jukka [Helsinki Univ. (Finland). Lab. of Radiochemistry

    2016-11-01

    Radiocarbon ({sup 14}C) is a top priority class radionuclide associated with the long-term safety of spent nuclear fuel disposal. Dissolved inorganic radiocarbon can be retained in bedrock via isotope exchange with calcite (CaCO{sub 3}) at solubility equilibrium with groundwater. In the present study, the rate of the isotope exchange process was investigated on synthetic calcite using batch experiments. Experiments were performed in solutions with a calcium concentration of 0.0002-0.1 M, including two synthetic reference groundwaters. The radiocarbon activity in the solutions decreased exponentially as a function of time, thus following first-order kinetics. The rate of isotope exchange was quantified from an exponential fit to the activity data over time. The rate of radiocarbon retention increased as a function of the calcium activity. The isotope exchange half-life was only 4.3 days at calcium ion activities over 0.01. This half-life is very much shorter than the half-life of {sup 14}C or the time scale of groundwater movements; consequently calcite can effectively retain radiocarbon from brackish and saline groundwaters.

  5. Comparison of Radiocarbon Ages for Multiproxy Paleoclimate Reconstruction of the Great Salt Lake, Utah

    Science.gov (United States)

    Nielson, K. E.; Bowen, G. J.; Eglinton, T. I.

    2008-12-01

    Multiproxy paleoclimate reconstructions from high sedimentation-rate systems offer promising opportunities to deconvolve multiple aspects climate system response to past forcing. However, the time-equivalence of proxies must be established before such reconstructions can be usefully interpreted. Differences in source ages, transport pathways, and surface residence times for substrates may lead to differences in lag times between proxy formation and deposition, compromising comparative analysis of data from multiple proxies. We used multi-substrate radiocarbon dating to investigate the potential for multi-proxy reconstruction of Holocene changes in the volume of the Great Salt Lake (GSL), Utah, based on the stable isotope composition of organic and inorganic substrates in lake sediment cores. Among potential substrates for this work are normal alkanes of vascular higher plant and algal origin, fossil cysts of lake-dwelling brine shrimp (Artemia), and micritic aragonite. Radiocarbon ages for all organic substrates (alkanes, cysts) sampled at any given core depth are concordant within analytical uncertainty and are similar to ages determined on land-plant debris and filamentous algae isolated from the sediment. Inorganic carbonate, in contrast, is depleted in 14C compare to the organic proxies, giving ages that were apparently 2000 to 3000 years older, likely due to winnowing and re-deposition of carbonate at the core site. These results suggest that the maximum temporal resolution achievable through analysis of mineral substrates is on the order of several millennia. Although the limited precision of the radiocarbon analysis precludes precise determination of the maximum potential resolution of organic-proxy based climate reconstructions, the relatively high sedimentation rates (50--150 cm/kyr) and age-equivalence of the substrates analyzed implies that sub- centennial scale resolution should be achievable throughout much of the Holocene portion of the GSL

  6. The Groningen AMS facility

    NARCIS (Netherlands)

    Wijma, S; Aerts, AT; vanderPlicht, J; Zondervan, A

    1996-01-01

    A new generation accelerator mass spectrometer has been in operation at the Centre for Isotope Research in Groningen, Netherlands since the summer of 1994. It is a 2.5 MV Tandetron, dedicated to radiocarbon. (C-14) analysis with high precision (<0.5%). We present here a report for the first year of

  7. Coral Radiocarbon Records of Indian Ocean Water Mass Mixing and Wind-Induced Upwelling Along the Coast of Sumatra, Indonesia

    Energy Technology Data Exchange (ETDEWEB)

    Guilderson, T P; Grumet, N S; Abram, N J; Beck, J W; Dunbar, R B; Gagan, M K; Hantoro, W S; Suwargadi, B W

    2004-02-06

    Radiocarbon ({sup 14}C) in the skeletal aragonite of annually banded corals track radiocarbon concentrations in dissolved inorganic carbon (DIC) in surface seawater. As a result of nuclear weapons testing in the 1950s, oceanic uptake of excess {sup 14}C in the atmosphere has increased the contrast between surface and deep ocean {sup 14}C concentrations. We present accelerator mass spectrometric (AMS) measurements of radiocarbon isotope ({Delta}{sup 14}C) in Porites corals from the Mentawai Islands, Sumatra (0 S, 98 E) and Watamu, Kenya (3 S, 39 E) to document the temporal and spatial evolution of the {sup 14}C gradient in the tropical Indian Ocean. The rise in {Delta}{sup 14}C in the Sumatra coral, in response to the maximum in nuclear weapons testing, is delayed by 2-3 years relative to the rise in coral {Delta}{sup 14}C from the coast of Kenya. Kenya coral {Delta}{sup 14}C values rise quickly because surface waters are in prolonged contact with the atmosphere. In contrast, wind-induced upwelling and rapid mixing along the coast of Sumatra entrains {sup 14}C-depleted water from the subsurface, which dilutes the effect of the uptake of bomb-laden {sup 14}C by the surface-ocean. Bimonthly AMS {Delta}{sup 14}C measurements on the Mentawai coral reveal mainly interannual variability with minor seasonal variability. The interannual signal may be a response to changes in the Walker circulation, the development of easterly wind anomalies, shoaling of the eastern thermocline, and upwelling of {sup 14}C-depleted water along the coast of Sumatra. Singular spectrum analysis of the Sumatra coral {Delta}{sup 14}C record reveals a significant 3-year periodicity. The results lend support to the concept that ocean atmosphere interactions between the Pacific and Indian Oceans operate in concert with the El Ni{tilde n}o-Southern Oscillation (ENSO).

  8. Τesting models for the beginnings of the Aurignacian and the advent of figurative art and music: the radiocarbon chronology of Geißenklösterle.

    Science.gov (United States)

    Higham, Thomas; Basell, Laura; Jacobi, Roger; Wood, Rachel; Ramsey, Christopher Bronk; Conard, Nicholas J

    2012-06-01

    The German site of Geißenklösterle is crucial to debates concerning the European Middle to Upper Palaeolithic transition and the origins of the Aurignacian in Europe. Previous dates from the site are central to an important hypothesis, the Kulturpumpe model, which posits that the Swabian Jura was an area where crucial behavioural developments took place and then spread to other parts of Europe. The previous chronology (critical to the model), is based mainly on radiocarbon dating, but remains poorly constrained due to the dating resolution and the variability of dates. The cause of these problems is disputed, but two principal explanations have been proposed: a) larger than expected variations in the production of atmospheric radiocarbon, and b) taphonomic influences in the site mixing the bones that were dated into different parts of the site. We reinvestigate the chronology using a new series of radiocarbon determinations obtained from the Mousterian, Aurignacian and Gravettian levels. The results strongly imply that the previous dates were affected by insufficient decontamination of the bone collagen prior to dating. Using an ultrafiltration protocol the chronometric picture becomes much clearer. Comparison of the results against other recently dated sites in other parts of Europe suggests the Early Aurignacian levels are earlier than other sites in the south of France and Italy, but not as early as recently dated sites which suggest a pre-Aurignacian dispersal of modern humans to Italy by ∼45000 cal BP. They are consistent with the importance of the Danube Corridor as a key route for the movement of people and ideas. The new dates fail to refute the Kulturpumpe model and suggest that Swabian Jura is a region that contributed significantly to the evolution of symbolic behaviour as indicated by early evidence for figurative art, music and mythical imagery.

  9. First Direct Dating for the Construction and Modification of the Baphuon Temple Mountain in Angkor, Cambodia.

    Directory of Open Access Journals (Sweden)

    Stéphanie Leroy

    Full Text Available Architecture represents key evidence of dynastic practice and change in the archaeological world. Chronologies for many important buildings and sequences, including the iconic temples of medieval Angkor in Cambodia, are based solely on indirect associations from inscriptions and architectural styles. The Baphuon temple, one of the last major buildings in Angkor without textual or scientifically-derived chronological evidence, is crucial both for the context and date of its construction and the period when its western façade was modified into a unique, gigantic Reclining Buddha. Its construction was part of a major dynastic change and florescence of the Hindu-Mahayana Buddhist state and the modification is the key evidence of Theravada Buddhist power after Angkor's decline in the 15th century. Using a newly-developed approach based on AMS radiocarbon dating to directly date four iron crampons integrated into the structure we present the first direct evidence for the history of the Baphuon. Comprehensive study of ferrous elements shows that both construction and modification were critically earlier than expected. The Baphuon can now be considered as the major temple associated with the imperial reformations and territorial consolidation of Suryavarman I (1010-1050 AD for whom no previous building to legitimize his reign could be identified. The Theravada Buddhist modification is a hundred years prior to the conventional 16th century estimation and is not associated with renewed use of Angkor. Instead it relates to the enigmatic Ayutthayan occupation of Angkor in the 1430s and 40s during a major period of climatic instability. Accurately dating iron with relatively low carbon content is a decisive step to test long-standing assumptions about architectural histories and political processes for states that incorporated iron into buildings (e.g., Ancient Greece, medieval India. Furthermore, this new approach has the potential to revise chronologies

  10. First Direct Dating for the Construction and Modification of the Baphuon Temple Mountain in Angkor, Cambodia.

    Science.gov (United States)

    Leroy, Stéphanie; Hendrickson, Mitch; Delqué-Kolic, Emmanuelle; Vega, Enrique; Dillmann, Philippe

    2015-01-01

    Architecture represents key evidence of dynastic practice and change in the archaeological world. Chronologies for many important buildings and sequences, including the iconic temples of medieval Angkor in Cambodia, are based solely on indirect associations from inscriptions and architectural styles. The Baphuon temple, one of the last major buildings in Angkor without textual or scientifically-derived chronological evidence, is crucial both for the context and date of its construction and the period when its western façade was modified into a unique, gigantic Reclining Buddha. Its construction was part of a major dynastic change and florescence of the Hindu-Mahayana Buddhist state and the modification is the key evidence of Theravada Buddhist power after Angkor's decline in the 15th century. Using a newly-developed approach based on AMS radiocarbon dating to directly date four iron crampons integrated into the structure we present the first direct evidence for the history of the Baphuon. Comprehensive study of ferrous elements shows that both construction and modification were critically earlier than expected. The Baphuon can now be considered as the major temple associated with the imperial reformations and territorial consolidation of Suryavarman I (1010-1050 AD) for whom no previous building to legitimize his reign could be identified. The Theravada Buddhist modification is a hundred years prior to the conventional 16th century estimation and is not associated with renewed use of Angkor. Instead it relates to the enigmatic Ayutthayan occupation of Angkor in the 1430s and 40s during a major period of climatic instability. Accurately dating iron with relatively low carbon content is a decisive step to test long-standing assumptions about architectural histories and political processes for states that incorporated iron into buildings (e.g., Ancient Greece, medieval India). Furthermore, this new approach has the potential to revise chronologies related to iron

  11. Time in tortoiseshell: a bomb radiocarbon-validated chronology in sea turtle scutes.

    Science.gov (United States)

    Van Houtan, Kyle S; Andrews, Allen H; Jones, T Todd; Murakawa, Shawn K K; Hagemann, Molly E

    2016-01-13

    Some of the most basic questions of sea turtle life history are also the most elusive. Many uncertainties surround lifespan, growth rates, maturity and spatial structure, yet these are critical factors in assessing population status. Here we examine the keratinized hard tissues of the hawksbill (Eretmochelys imbricata) carapace and use bomb radiocarbon dating to estimate growth and maturity. Scutes have an established dietary record, yet the large keratin deposits of hawksbills evoke a reliable chronology. We sectioned, polished and imaged posterior marginal scutes from 36 individual hawksbills representing all life stages, several Pacific populations and spanning eight decades. We counted the apparent growth lines, microsampled along growth contours and calibrated Δ(14)C values to reference coral series. We fit von Bertalanffy growth function (VBGF) models to the results, producing a range of age estimates for each turtle. We find Hawaii hawksbills deposit eight growth lines annually (range 5-14), with model ensembles producing a somatic growth parameter (k) of 0.13 (range 0.1-0.2) and first breeding at 29 years (range 23-36). Recent bomb radiocarbon values also suggest declining trophic status. Together, our results may reflect long-term changes in the benthic community structure of Hawaii reefs, and possibly shed light on the critical population status for Hawaii hawksbills.

  12. Radiocarbon in tropical tree rings during the Little Ice Age

    Science.gov (United States)

    Hua, Q.; Barbetti, M.; Zoppi, U.; Fink, D.; Watanasak, M.; Jacobsen, G. E.

    2004-08-01

    Cross-dated tree-ring cores (Pinus merkusii) from north-central Thailand, spanning AD 1620-1780, were used to investigate atmospheric 14C for the tropics during the latter part of the Little Ice Age. In addition, a cross-dated section of Huon pine from western Tasmania, covering the same period of time, was investigated. A total of 16 pairs of decadal samples were extracted to alpha-cellulose for AMS 14C analysis using the ANTARES facility at ANSTO. The 14C results from Thailand follow the trend of the southern hemisphere, rather than that of the northern hemisphere. This is a surprising result, and we infer that atmospheric 14C for north-central Thailand, at 17° N, was strongly influenced by the entrainment of southern hemisphere air parcels during the southwest Asian monsoon, when the Inter-Tropical Convergence Zone moves to the north of our sampling site. Such atmospheric transport and mixing are therefore considered to be one of the principal mechanisms for regional 14C offsets.

  13. Urvina Bay, Galapagos Coral Radiocarbon (delta 14C) Data for 1956 to 1982

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Urvina Bay coral radiocarbon (14C) timeseries. (90 deg W, 0.5 deg S) Coral radiocarbon (Delta-14C) on untreated, low-speed drilled samples. Precision is +/- 4 per...

  14. High-precision radiocarbon chronometry of ancient Egypt, and comparisons with Nubia, Palestine and Mesopotamia

    Energy Technology Data Exchange (ETDEWEB)

    Hassan, F.A.; Robinson, S.W.

    1987-03-01

    The use of radiocarbon age measurements in historical chronology is examined for ancient Egypt and neighbouring regions. A methodology is presented aimed at improving the reliability and precision of radiocarbon age determinations.

  15. The AMS experiment

    CERN Multimedia

    Laurent Guiraud

    1999-01-01

    The Alpha Magnetic Spectrometer (AMS) detector will be installed as a particle physics experiment on the International Space Station. It will look for antimatter pockets in space. AMS is a CERN recognised experiment.

  16. Radiocarbon in food : a non-problem of health effects

    NARCIS (Netherlands)

    van der Plicht, J.; Beijers, J. P. M.

    2011-01-01

    Recently it has come to our attention that a paper was published in this journal entitled "recycling greenhouse gas fossil fuel emissions into low radiocarbon food products to reduce human genetic damage" (Williams in Environ Chem Lett 5:197-202, 2007). In this article, it is argued that food grown

  17. Dendrochronology and radiocarbon dating of conifer trees and buried logs from the Stanley River, Tasmania

    Energy Technology Data Exchange (ETDEWEB)

    Cook, E. [Columbia Univ., Palisades, NY (United States). Tree-Ring Lab; Barbetti, M.; Taylor, G.; Yu, Z.; Thompson, B.; Weeks, L. [Sydney Univ., Sydney, NSW (Australia). The NWG Macintosh Centre for Quaternary Dating; Buckley, B. [Tasmania Univ., Sandy Bay, TAS (Australia). Inst of Antarctic and Southern Ocean Studies

    1997-12-31

    Full text: Dendrochronological studies are being carried out on two endemic conifer species in the Stanley River area of western Tasmania. Living trees are growing along the river banks, adjacent floodplain areas, and occasionally on the lower hill-slopes. Many ancient logs are exposed in the bed and banks of the river, and several major excavations have been carried out in floodplain sediments up to a hundred metres distant from the present river channel. A tree-ring chronology for Huon pine (Lagarostrobos franklinii) now extends from the present back to 571 BC. This chronology has been constructed using cores from living trees (up to 1400 years old), sections from trees felled during logging operations in the early 1980s, and sections from subfossil logs in the river banks and floodplain sediments. Living celery-top pine (Phyllocladus aspleniifolius) trees are up to 500 years old, and a short chronology is being developed for this species as well. Large excavations have been carried out over several years in floodplain sediments, and sections have now been taken from a total of 350 subfossil logs. Both Huon and celery-top pine are represented in the collection. They range in age from >38 ka to modern, with good coverage for the periods 9-3.5 ka and from 2.5 ka to the present. A floating tree-ring chronology for Huon pine has been established for the period ca. 7200-3500 cal BP, and is gradually being augmented. In the collection of about 350 ancient conifer logs from the Stanley River, about 150 currently have known ages while the remaining 200 have yet to be studied. Most of them have ages less than 9000 cal BP, but about 10% of them are older. Four of them are more than 30,000 years old, and may be Last Interglacial in age. Nine of them are known to be between 18,000 and 10,000 years old, and six are between 10,000 and 9,000 years old. Our augmented collection has become an increasingly important archive for further tree-ring and carbon isotope studies. Paper no. 35; 1 fig.

  18. Direct radiocarbon dating and genetic analyses on the purported Neanderthal mandible from the Monti Lessini (Italy)

    DEFF Research Database (Denmark)

    Talamo, Sahra; Hajdinjak, Mateja; Mannino, Marcello;

    2016-01-01

    Anatomically modern humans replaced Neanderthals in Europe around 40,000 years ago. The demise of the Neanderthals and the nature of the possible relationship with anatomically modern humans has captured our imagination and stimulated research for more than a century now. Recent chronological...... studies suggest a possible overlap between Neanderthals and anatomically modern humans of more than 5,000 years. Analyses of ancient genome sequences from both groups have shown that they interbred multiple times, including in Europe. A potential place of interbreeding is the notable Palaeolithic site...... of the lithic assemblage of layer I. Surprisingly we found that the Riparo Mezzena mandible is not from a Neanderthal but belonged to an anatomically modern human. Furthermore, we found no evidence for the presence of Neanderthal remains among 11 of the 13 cranial and post-cranial fragments re...

  19. Periodicity of growth rings in Juniperus procera from Ethiopia inferred from crossdating and radiocarbon dating.

    NARCIS (Netherlands)

    Wils, T.; Robertson, I.; Eshetu, Z.; Sass-Klaassen, U.; Koprowski, M.

    2009-01-01

    African pencil cedar (Juniperus procera Hochst. ex Endlicher 1847) is a tropical, irregularly growing species that can produce annual growth rings in response to an annual cycle of wet and dry seasons. In this paper, we assess the periodicity of growth-ring formation for 13 stem discs from a site in

  20. Radiocarbon dating of the bronze age bone pins from Eurasian steppe

    NARCIS (Netherlands)

    Shishlina, Natalia I.; Van der Plicht, Johan; Zazovskaya, Elya P.

    2011-01-01

    Bone catapult and hammer-headed pins played one of very specific roles in funerary offerings in the Bronze Age graves uncovered in the Eurasian Steppes and the North Caucasus. Scholars used different types of pins as key grave offerings for numerous chronological models. For the first time eight pin

  1. Radiocarbon dating of elk (Alces alces), an economic and symbolic resource in prehistory

    DEFF Research Database (Denmark)

    Philippsen, Bente

    The European elk, “moose” in American English, was an important resource in the prehistory of Northern Europe. On some sites, it was the most important species in the economy. Furthermore, numerous examples of mobile and non-mobile art show the importance of the elk as a symbolic or ritualistic...

  2. Radiocarbon dates of the medieval period stone anchors from Dabhol, west coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    Gaur, A; Sundaresh; Tripati, S.; Vora, K.H.

    Dabhol was an important medieval-period port town on the Maharashtra coast. An archaeological exploration at Dabhol has revealed four stone anchors with remains of wood in fluke hole. These anchors were retrieved from Dabhol creek during a dredging...

  3. Direct radiocarbon dating and genetic analyses on the purported Neanderthal mandible from the Monti Lessini (Italy)

    DEFF Research Database (Denmark)

    Talamo, Sahra; Hajdinjak, Mateja; Mannino, Marcello

    2016-01-01

    Anatomically modern humans replaced Neanderthals in Europe around 40,000 years ago. The demise of the Neanderthals and the nature of the possible relationship with anatomically modern humans has captured our imagination and stimulated research for more than a century now. Recent chronological stu...

  4. Radiocarbon dating reveals minimal collagen turnover in both healthy and osteoarthritic human cartilage

    DEFF Research Database (Denmark)

    Heinemeier, Katja M.; Schjerling, Peter; Heinemeier, Jan

    2016-01-01

    The poor regenerative capacity of articular cartilage presents a major clinical challenge and may relate to a limited turnover of the cartilage collagen matrix. However, the collagen turnover rate during life is not clear, and it is debated whether osteoarthritis (OA) can influence it. Using...... the carbon-14 ((14)C) bomb-pulse method, life-long replacement rates of collagen were measured in tibial plateau cartilage from 23 persons born between 1935 and1997 (15 and 8 persons with OA and healthy cartilage, respectively). The (14)C levels observed in cartilage collagen showed that, virtually......, no replacement of the collagen matrix happened after skeletal maturity and that neither OA nor tissue damage, per se, influenced collagen turnover. Regional differences in (14)C content across the joint surface showed that cartilage collagen located centrally on the joint surface is formed several years earlier...

  5. Compound-specific radiocarbon analysis - Analytical challenges and applications

    Energy Technology Data Exchange (ETDEWEB)

    Mollenhauer, G; Rethemeyer, J [Alfred-Wegener Institute for Polar and Marine Research Am Handelshafen 12, 27570 Bremerhaven (Germany)], E-mail: Gesine.Mollenhauer@awi.de

    2009-01-01

    Within the last decades, techniques have become available that allow measurement of isotopic compositions of individual organic compounds (compound-specific isotope measurements). Most often the carbon isotopic composition of these compounds is studied, including stable carbon ({delta}{sup 13}C) and radiocarbon ({delta}{sup 14}C) measurements. While compound-specific stable carbon isotope measurements are fairly simple, and well-established techniques are widely available, radiocarbon analysis of specific organic compounds is a more challenging method. Analytical challenges include difficulty obtaining adequate quantities of sample, tedious and complicated laboratory separations, the lack of authentic standards for measuring realistic processing blanks, and large uncertainties in values of {delta}{sup 14}C at small sample sizes. The challenges associated with sample preparation for compound-specific {delta}{sup 14}C measurements will be discussed in this contribution. Several years of compound-specific radiocarbon analysis have revealed that in most natural samples, purified organic compounds consist of heterogeneous mixtures of the same compound. These mixtures could derive from multiple sources, each having a different initial reservoir age but mixed in the same terminal reservoir, from a single source but mixed after deposition, or from a prokaryotic organism using variable carbon sources including mobilization of ancient carbon. These processes not only represent challenges to the interpretation of compound-specific radiocarbon data, but provide unique tools for the understanding of biogeochemical and sedimentological processes influencing the preserved organic geochemical records in marine sediments. We will discuss some examples where compound-specific radiocarbon analysis has provided new insights for the understanding of carbon source utilization and carbon cycling.

  6. Radiocarbon method in environmental monitoring of CO{sub 2} emission

    Energy Technology Data Exchange (ETDEWEB)

    Rakowski, Andrzej Z., E-mail: arakowski@leibniz.uni-kiel.de [Leibniz Laboratory for Radiometric Dating and Isotope Research, University of Kiel, Max Eyth Str. 11-13, 24118 Kiel (Germany); Radiocarbon Laboratory, Institute of Physics, Silesian University of Technology, ul. Boleslawa Krzywoustego 2, 44-100 Gliwice (Poland); Nadeau, Marie-Josee [Leibniz Laboratory for Radiometric Dating and Isotope Research, University of Kiel, Max Eyth Str. 11-13, 24118 Kiel (Germany); Nakamura, Toshio [Center for Chronological Research, Nagoya University, Furocho, Chikusa-ku, 64-8602 Nagoya (Japan); Pazdur, Anna; Pawelczyk, Slawomira; Piotrowska, Natalia [Radiocarbon Laboratory, Institute of Physics, Silesian University of Technology, ul. Boleslawa Krzywoustego 2, 44-100 Gliwice (Poland)

    2013-01-15

    New results of carbon isotopic composition from tree rings have been analyzed. {Delta}{sup 14}C and {delta}{sup 13}C data, representing the isotopic composition of carbon in 'clean air', were obtained from annual rings of a pine tree (Pinus sylvestris) taken in the Niepolomice area, 25 km east Krakow, Poland. All samples were processed to extract {alpha}-cellulose, and the radiocarbon concentration in each annual ring was measured using AMS at University of Nagoya. Stable isotopic composition of carbon was determined using isotope ratio mass spectrometry. The dataset covers the growth period between 1960 and 2003. The average difference between radiocarbon concentrations in Niepolomice and the North Hemisphere zone 1 (NH zone 1) for the period between 1960 and 1999 is 3.5 {+-} 1.6 Per-Mille-Sign . These data are compared with previously presented results from the city of Krakow, where a local decrease in {sup 14}C concentration was observed due to local CO{sub 2} emission from fossil fuel use. The differences in observed {sup 14}C concentrations were used to estimate a magnitude of the local Suess effect in Krakow. Based on mass balance equations for CO{sub 2}{sup 14}C concentrations, it was possible to calculate the CO{sub 2} concentration associated with fossil fuel emission (C{sub foss}) into the atmosphere. The highest values of C{sub foss} were recorded in the years 1986 (11.9 {+-} 1.4 ppm V) and 1983 (8.1 {+-} 1.3 ppm V), while the lowest value of 0.6 {+-} 1.8 ppm V was recorded in 2001.

  7. Geographic and temporal trends in proboscidean and human radiocarbon histories during the late Pleistocene

    Science.gov (United States)

    Ugan, Andrew; Byers, David

    2007-12-01

    The causes of large animal extinctions at the end of the Pleistocene remain a hotly debated topic focused primarily on the effects of human over hunting and climate change. Here we examine multiple, large radiocarbon data sets for humans and extinct proboscideans and explore how variation in their temporal and geographic distributions were related prior to proboscidean extinction. These data include 4532 archaeological determinations from Europe and Siberia and 1177 mammoth and mastodont determinations from Europe, Siberia, and North America. All span the period from 45,000 to 12,000 calendar years BP. We show that while the geographic ranges of dated human occupations and proboscidean remains overlap across the terminal Pleistocene of the Old World, the two groups remain largely segregated and increases in the frequency of human occupations do not coincide with declines in proboscidean remains. Prior to the Last Glacial Maximum (LGM; ca 21,000 years BP), archaeological 14C determinations increase slightly in frequency worldwide while the frequency of dated proboscidean remains varies depending on taxon and location. After the LGM, both sympatric and allopatric groups of humans and proboscideans increase sharply as climatic conditions ameliorate. Post-LGM radiocarbon frequencies among proboscideans peak at different times, also depending upon taxon and location. Woolly mammoths in Beringia reach a maximum and then decline beginning between 16,000 and 15,500 years BP, woolly mammoths in Europe and Siberia ca 14,500 and 13,500 BP, and Columbian mammoth and American mastodont only after 13,000 BP. Declines among woolly mammoths appear to coincide with the restructuring of biotic communities following the Pleistocene-Holocene transition.

  8. A new procedure for extraction of collagen from modern and archaeological bones for {sup 14}C dating

    Energy Technology Data Exchange (ETDEWEB)

    Maspero, F. [CUDaM, University of Milano Bicocca, Milano (Italy); Sala, S.; Papagni, A. [University of Milano Bicocca, Materials Science Department, Milano (Italy); Fedi, M.E. [INFN sezione di Firenze, Sesto Fiorentino (Firenze) (Italy); Martini, M. [CUDaM, University of Milano Bicocca, Milano (Italy); University of Milano Bicocca, Materials Science Department, Milano (Italy); INFN sezione di Milano Bicocca, Milano (Italy)

    2011-10-15

    Bones are potentially the best age indicators in a stratigraphic study, because they are closely related to the layer in which they are found. Collagen is the most suitable fraction and is the material normally used in radiocarbon dating. Bone contaminants can strongly alter the carbon isotopic fraction values of the samples, so chemical pretreatment for {sup 14} C dating by accelerator mass spectrometry (AMS) is essential. The most widespread method for collagen extraction is based on the Longin procedure, which consists in HCl demineralization to dissolve the inorganic phase of the samples, followed by dissolution of collagen in a weak acid solution. In this work the possible side effects of this procedure on a modern bone are presented; the extracted collagen was analyzed by ATR-IR spectroscopy. An alternative procedure, based on use of HF instead of HCl, to minimize unwanted degradation of the organic fraction, is also given. A study by ATR-IR spectroscopic analysis of collagen collected after different demineralization times and with different acid volumes, and a study of an archaeological sample, are also presented. (orig.)

  9. Isotopic analyses of food crusts on pottery: Implications for dating and palaeocuisine reconstructions

    DEFF Research Database (Denmark)

    Philippsen, Bente

    2015-01-01

    relevant for reconstructing the diet, but also important for 14C-dating. Resources from sea- or freshwater can cause substantial radiocarbon reservoir effects. For a reliable 14C-dating, they therefore have to be identified. This study presents 14C-datings of the earliest pottery of Schleswig......-Holstein at the inland Ertebølle sites Kayhude and Schlamersdorf (Fig. 1). The coastal Ertebølle and Funnel Beaker site Neustadt was studied for comparison....

  10. Upper Palaeolithic and Mesolithic human fossils from Moravia and Bohemia (Czech Republic) : Some new C-14 dates

    NARCIS (Netherlands)

    Svoboda, JA; Van der Plicht, J; Kuzelka, [No Value; Svoboda, Jiři A.; Kuželka, Vítězslav

    2002-01-01

    New radiocarbon dates from four Moravian and bohemian sites are presented and linked to previous work on the depositional contexts of human fossils at similar sites in the region. Whilst dates from Mladec confirm its early Upper Palaeolithic age, the chronologies of the other three sites require rev

  11. Dating North European mammoths (Mammuthus primigenius Blum.): a nearly continuous record from 53 ka to 11 ka

    Science.gov (United States)

    Ukkonen, P.; Aaris-Sørensen, K.; Arppe, L.; Clark, P. U.; Daugnora, L.; Lister, A.; Lõugas, L.; Seppä, H. A.; Stuart, A. J.; Wojtal, P.; Zupins, I.

    2010-05-01

    Remains of the woolly mammoth (Mammuthus primigenius Blumenbach) are found all over Eurasia except in mountainous areas of Scandinavia and in western Iberian Peninsula. In the core area of the Scandinavian Ice Sheet, they are the only group of animal remains to have survived until today in abundant numbers, and so are an important source of information about the past fauna, their environment, and the climate. Our data include mammoth remains found in Sweden, Denmark, Lithuania, Latvia, Estonia and Finland. Mammoth finds from northern Germany are not included in this study, but some dates have been published elsewhere. We lack data from northern Poland, but we include finds from southern Poland, approximately 500 km directly south of the main study area, as a point of comparison. Approximately 300 localities with mammoth molars, tusks and bones are known from the study area. Most of the finds (90%) are isolated skeletal elements. In marginal areas of the SIS, in Denmark and Lithuania, associated elements are also found together at some localities, but whole or partial skeletons are found only in southern Poland. The mammoth data were collected by the authors from published papers and reports as well as by direct survey of museum collections. A total of 104 radiocarbon dates were documented: 78 from the circum-Baltic area and 26 from southern Poland. From the dates, 73 were previously published by the authors, and eight by other researchers. A total of 23 dates are new. Most of the specimens (93) were dated using AMS, and 11 using conventional radiocarbon dating. Finite dates were calibrated using the download version of CalPal-2007 (Weninger et al., 2008) with calibration data set CalPal-2007Hulu (Weninger and Jöris, 2007). The spatio-temporal distribution of mammoth remains around the Baltic Sea suggests that the species was widely spread in north-eastern Europe during ice-free intervals of the Weichselian glaciation. Mammoths were present in north-eastern Europe

  12. A new AMS facility in Mexico

    Science.gov (United States)

    Solís, C.; Chávez-Lomelí, E.; Ortiz, M. E.; Huerta, A.; Andrade, E.; Barrios, E.

    2014-07-01

    A new Accelerator Mass Spectrometry system has been installed at the Institute of Physics of the National Autonomous University of Mexico (UNAM). A sample preparation chemistry laboratory equipped with computer controlled graphitization equipment (AGEIII) has also been established. Together both facilities constitute the LEMA (Laboratorio de Espectrometría de Masas con Aceleradores) first of its kind in Mexico. High sensitivity characterization of the concentration in a sample of 14C as well as 10Be, 26Al, 129I and Pu are now possible. Since the demand for 14C dating is far more abundant, a data analysis program was developed in the cross-platform programming language Python in order to calculate radiocarbon age. Results from installation, acceptance tests and the first results of 14C analyses of reference materials prepared in our own facility are presented.

  13. A new AMS facility in Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Solís, C., E-mail: corina@fisica.unam.mx; Chávez-Lomelí, E.; Ortiz, M.E.; Huerta, A.; Andrade, E.; Barrios, E.

    2014-07-15

    A new Accelerator Mass Spectrometry system has been installed at the Institute of Physics of the National Autonomous University of Mexico (UNAM). A sample preparation chemistry laboratory equipped with computer controlled graphitization equipment (AGEIII) has also been established. Together both facilities constitute the LEMA (Laboratorio de Espectrometría de Masas con Aceleradores) first of its kind in Mexico. High sensitivity characterization of the concentration in a sample of {sup 14}C as well as {sup 10}Be, {sup 26}Al, {sup 129}I and Pu are now possible. Since the demand for {sup 14}C dating is far more abundant, a data analysis program was developed in the cross-platform programming language Python in order to calculate radiocarbon age. Results from installation, acceptance tests and the first results of {sup 14}C analyses of reference materials prepared in our own facility are presented.

  14. Late Holocene Radiocarbon Variability in Northwest Atlantic Slope Waters

    Energy Technology Data Exchange (ETDEWEB)

    Sherwood, O; Edinger, E; Guilderson, T P; Ghaleb, B; Risk, M J; Scott, D B

    2008-08-15

    Deep-sea gorgonian corals secrete a 2-part skeleton of calcite, derived from dissolved inorganic carbon at depth, and gorgonin, derived from recently fixed and exported particulate organic matter. Radiocarbon contents of the calcite and gorgonin provide direct measures of seawater radiocarbon at depth and in the overlying surface waters, respectively. Using specimens collected from Northwest Atlantic slope waters, we generated radiocarbon records for surface and upper intermediate water layers spanning the pre- and post bomb-{sup 14}C eras. In Labrador Slope Water (LSW), convective mixing homogenizes the pre-bomb {Delta}{sup 14}C signature (-67 {+-} 4{per_thousand}) to at least 1000 m depth. Surface water bomb-{sup 14}C signals were lagged and damped (peaking at {approx} +45{per_thousand} in the early 1980s) relative to other regions of the northwest Atlantic, and intermediate water signals were damped further. Off southwest Nova Scotia, the vertical gradient in {Delta}{sup 14}C is much stronger. In surface water, pre-bomb {Delta}{sup 14}C averaged -75 {+-} 5{per_thousand}. At 250-475 m depth, prebomb {Delta}{sup 14}C oscillated quasi-decadally between -80 and -100{per_thousand}, likely reflecting interannual variability in the presence of Labrador Slope Water vs. Warm Slope Water (WSW). Finally, subfossil corals reveal no systematic changes in vertical {Delta}{sup 14}C gradients over the last 1200 years.

  15. AMS Data Analysis Overview

    Energy Technology Data Exchange (ETDEWEB)

    Malchow, Russell L. [National Security Technologies, LLC

    2015-04-20

    This presentation discusses standard techniques and processes used for radiation mapping (RM) via an AMS, Aerial Measurement System. The advantages and shortcomings of standard AMS-based RM are presented, along with some suggested areas for improvement. Issues touched on include what gets counted, data quality, background correction, data processing, altitude correction, isotope extraction, contouring, and time shift.

  16. Who Am I?

    Institute of Scientific and Technical Information of China (English)

    仇福燕

    2006-01-01

    Hello, boys and girls. We all know summer is coming and days become long and nights become short. It’ssohot!Comeon, baby! I can make you cool. I am white. I am sweet, cool and soft. I live in a colorful paper box. I’m made from milk, chocolate and water. Many children like me very much. But if you eat too much, you will have got a stomachache(肚子疼). Guess! Who am I? Yes, you are very clever. I am an ice cream.★指导老师: 施俊亚 难度系数: ☆☆☆☆Who Am I?$海门实验学校小学部五(1)班@仇福燕

  17. Using the Suess effect on the stable carbon isotope to distinguish the future from the past in radiocarbon

    Science.gov (United States)

    Köhler, Peter

    2016-12-01

    The depletion of 14C due to the emission of radiocarbon-free fossil fuels (14C Suess effect) might lead to similar values in future and past radiocarbon signatures potentially introducing ambiguity in dating. I here test if a similar impact on the stable carbon isotope via the 13C Suess effect might help to distinguish between ancient and future carbon sources. To analyze a wide range of possibilities, I add to future emission scenarios carbon dioxide reduction (CDR) mechanisms, which partly enhance the depletion of atmospheric {{{Δ }}}14{{C}} already caused by the 14C Suess effect. The 13C Suess effect leads to unprecedented depletion in {δ }13{{C}} shifting the carbon cycle to a phase space in {{{Δ }}}14{{C}}{--}{δ }13{{C}}, in which the system has not been during the last 50 000 years and therefore the similarity in past and future {{{Δ }}}14{{C}} (the ambiguity in 14C dating) induced by fossil fuels can in most cases be overcome by analyzing 13C. Only for slow changing reservoirs (e.g. deep Indo-Pacific Ocean) or when CDR scenarios are dominated by bioenergy with capture and storage the effect of anthropogenic activities on 13C does not unequivocally identify between past and future carbon cycle changes.

  18. Radiometric dating of the Siloam Tunnel, Jerusalem.

    Science.gov (United States)

    Frumkin, Amos; Shimron, Aryeh; Rosenbaum, Jeff

    2003-09-11

    The historical credibility of texts from the Bible is often debated when compared with Iron Age archaeological finds (refs. 1, 2 and references therein). Modern scientific methods may, in principle, be used to independently date structures that seem to be mentioned in the biblical text, to evaluate its historical authenticity. In reality, however, this approach is extremely difficult because of poor archaeological preservation, uncertainty in identification, scarcity of datable materials, and restricted scientific access into well-identified worship sites. Because of these problems, no well-identified Biblical structure has been radiometrically dated until now. Here we report radiocarbon and U-Th dating of the Siloam Tunnel, proving its Iron Age II date; we conclude that the Biblical text presents an accurate historic record of the Siloam Tunnel's construction. Being one of the longest ancient water tunnels lacking intermediate shafts, dating the Siloam Tunnel is a key to determining where and when this technological breakthrough took place. Siloam Tunnel dating also refutes a claim that the tunnel was constructed in the second century bc.

  19. Between a rock and a soft place: Using optical ages to date ancient clam gardens on the Pacific Northwest

    Science.gov (United States)

    Neudorf, Christina M.; Smith, Nicole; Lepofsky, Dana; Toniello, Ginevra; Lian, Olav B.

    2017-01-01

    Rock-walled archaeological features are notoriously hard to date, largely because of the absence of suitable organic material for radiocarbon dating. This study demonstrates the efficacy of dating clam garden wall construction using optical dating, and uses optical ages to determine how sedimentation rates in the intertidal zone are affected by clam garden construction. Clam gardens are rock-walled, intertidal terraces that were constructed and maintained by coastal First Nation peoples to increase bivalve habitat and productivity. These features are evidence of ancient shellfish mariculture on the Pacific Northwest and, based on radiocarbon dating, date to at least the late Holocene. Optical dating exploits the luminescence signals of quartz or feldspar minerals to determine the last time the minerals were exposed to sunlight (i.e., their burial age), and thus does not require the presence of organic material. Optical ages were obtained from three clam garden sites on northern Quadra Island, British Columbia, and their reliability was assessed by comparing them to radiocarbon ages derived from shells underneath the clam garden walls, as well as below the terrace sediments. Our optical and radiocarbon ages suggest that construction of these clam garden walls commenced between ~1000 and ~1700 years ago, and our optical ages suggest that construction of the walls was likely incremental and increased sedimentation rates in the intertidal zone by up to fourfold. Results of this study show that when site characteristics are not amenable to radiocarbon dating, optical dating may be the only viable geochronometer. Furthermore, dating rock-walled marine management features and their geomorphic impact can lead to significant advances in our understanding of the intimate relationships that Indigenous peoples worldwide developed with their seascapes. PMID:28182645

  20. Between a rock and a soft place: Using optical ages to date ancient clam gardens on the Pacific Northwest.

    Science.gov (United States)

    Neudorf, Christina M; Smith, Nicole; Lepofsky, Dana; Toniello, Ginevra; Lian, Olav B

    2017-01-01

    Rock-walled archaeological features are notoriously hard to date, largely because of the absence of suitable organic material for radiocarbon dating. This study demonstrates the efficacy of dating clam garden wall construction using optical dating, and uses optical ages to determine how sedimentation rates in the intertidal zone are affected by clam garden construction. Clam gardens are rock-walled, intertidal terraces that were constructed and maintained by coastal First Nation peoples to increase bivalve habitat and productivity. These features are evidence of ancient shellfish mariculture on the Pacific Northwest and, based on radiocarbon dating, date to at least the late Holocene. Optical dating exploits the luminescence signals of quartz or feldspar minerals to determine the last time the minerals were exposed to sunlight (i.e., their burial age), and thus does not require the presence of organic material. Optical ages were obtained from three clam garden sites on northern Quadra Island, British Columbia, and their reliability was assessed by comparing them to radiocarbon ages derived from shells underneath the clam garden walls, as well as below the terrace sediments. Our optical and radiocarbon ages suggest that construction of these clam garden walls commenced between ~1000 and ~1700 years ago, and our optical ages suggest that construction of the walls was likely incremental and increased sedimentation rates in the intertidal zone by up to fourfold. Results of this study show that when site characteristics are not amenable to radiocarbon dating, optical dating may be the only viable geochronometer. Furthermore, dating rock-walled marine management features and their geomorphic impact can lead to significant advances in our understanding of the intimate relationships that Indigenous peoples worldwide developed with their seascapes.

  1. Laser Ablation - Accelerator Mass Spectrometry: An Approach for Rapid Radiocarbon Analyses of Carbonate Archives at High Spatial Resolution.

    Science.gov (United States)

    Welte, Caroline; Wacker, Lukas; Hattendorf, Bodo; Christl, Marcus; Fohlmeister, Jens; Breitenbach, Sebastian F M; Robinson, Laura F; Andrews, Allen H; Freiwald, André; Farmer, Jesse R; Yeman, Christiane; Synal, Hans-Arno; Günther, Detlef

    2016-09-06

    A new instrumental setup, combining laser ablation (LA) with accelerator mass spectrometry (AMS), has been investigated for the online radiocarbon ((14)C) analysis of carbonate records. Samples were placed in an in-house designed LA-cell, and CO2 gas was produced by ablation using a 193 nm ArF excimer laser. The (14)C/(12)C abundance ratio of the gas was then analyzed by gas ion source AMS. This configuration allows flexible and time-resolved acquisition of (14)C profiles in contrast to conventional measurements, where only the bulk composition of discrete samples can be obtained. Three different measurement modes, i.e. discrete layer analysis, survey scans, and precision scans, were investigated and compared using a stalagmite sample and, subsequently, applied to terrestrial and marine carbonates. Depending on the measurement mode, a precision of typically 1-5% combined with a spatial resolution of 100 μm can be obtained. Prominent (14)C features, such as the atomic bomb (14)C peak, can be resolved by scanning several cm of a sample within 1 h. Stalagmite, deep-sea coral, and mollusk shell samples yielded comparable signal intensities, which again were comparable to those of conventional gas measurements. The novel LA-AMS setup allowed rapid scans on a variety of sample materials with high spatial resolution.

  2. Kimberley rock art dating project

    Energy Technology Data Exchange (ETDEWEB)

    Walsh, G.L. [Takarakka Rock Art Research Centre, NT, (Australia); Morwood, M. [New England University, Armidale, NSW, (Australia). Dept of Archaeology and Palaeoanthropology

    1997-12-31

    The art`s additional value, unequalled by traditionally recognised artefacts, is its permanent pictorial documentation presenting a `window` into the otherwise intangible elements of perceptions, vision and mind of pre-historic cultures. Unfortunately it`s potential in establishing Kimberley archaeological `big picture` still remains largely unrecognised. Some of findings of the Kimberley Rock Art Dating Project, using AMS and optical stimulated luminescence (OSL) dating techniques, are outlined. It is estimated that these findings will encourage involvement by a greater diversity of specialist disciplines to tie findings into levels of this art sequence as a primary reference point. The sequence represents a sound basis for selecting specific defined images for targeting detailed studies by a range of dating technique. This effectively removes the undesirable ad hoc sampling of `apparently old paintings`; a process which must unavoidably remain the case with researchers working on most global bodies of rock art.

  3. Early Bronze Jericho : High-precision C-14 dates of short-lived palaeobotanic remains

    NARCIS (Netherlands)

    Bruins, HJ; Van Der Plicht, J; Mook, W.G.

    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,

  4. Memory effects using an elemental analyser to combust radiocarbon samples: Failure and recovery

    Energy Technology Data Exchange (ETDEWEB)

    Fedi, M.E. [INFN Sezione di Firenze, via Sansone 1, 50019 Sesto Fiorentino (Italy); Liccioli, L. [INFN Sezione di Firenze, via Sansone 1, 50019 Sesto Fiorentino (Italy); Dipartimento di Chimica Ugo Schiff, Università di Firenze, via della Lastruccia 3-13, 50019 Sesto Fiorentino (Italy); Castelli, L. [INFN Sezione di Firenze, via Sansone 1, 50019 Sesto Fiorentino (Italy); Czelusniak, C.; Giuntini, L.; Mandò, P.A. [INFN Sezione di Firenze, via Sansone 1, 50019 Sesto Fiorentino (Italy); Dipartimento di Fisica e Astronomia, Università di Firenze, via Sansone 1, 50019 Sesto Fiorentino (Italy); Palla, L. [INFN Sezione di Pisa e Dipartimento di Fisica, Università di Pisa, Largo Pontecorvo 3, 56127 Pisa (Italy); Taccetti, F. [INFN Sezione di Firenze, via Sansone 1, 50019 Sesto Fiorentino (Italy)

    2015-10-15

    In the combustion and graphitization line for {sup 14}C-AMS samples used at INFN-LABEC for archaeological and geological applications, samples are burnt using an elemental analyser (EA). Advantages and drawbacks of EAs are known, a drawback being the possibility to introduce some contaminations or memory effects. Different parts inside an EA, e.g. the autosampler and the gas-chromatography column, might in principle be responsible of such problems. During a measurement run some time ago, we measured, indeed, radiocarbon concentration values somewhat higher than usual in nominally blank samples. These “bad” data could be explained by memory effects. By assuming a constant contribution from the sample of the prior combustion, this effect might be corrected: indeed, by repeating cycles of sequential combustions of standards and blanks, we observed a good reproducibility of the amount of contamination from the previous sample needed to explain the results. However, we were obviously unhappy with the fact itself of such corrections being needed, and several tests were performed to identify the source of contamination and eliminate it. Eventually, we succeeded in finding the cause of this failure and in recovering the full performance of the system.

  5. ARCHAEOMAGNETIC DATING OF THE ERUPTION OF XITLE VOLCANO, BASIN OF MEXICO: IMPLICATIONS FOR THE MESOAMERICAN CENTERS OF CUICUILCO AND TEOTIHUACAN (Datación arqueomagnética de la erupción del volcán Xitle, cuenca de México: implicaciones para los centros mesoamericanos de Cuicuilco y Teotihuacan)

    OpenAIRE

    Jaime Urrutia-Fucugauchi; Avto Goguitchaichvili; Ligia Pérez-Cruz; Juan Morales

    2016-01-01

    The Cuicuilco archaeological site in southern Basin of Mexico is covered by lava flows from the Xitle volcano. Dating the Xitle eruption and Cuicuilco abandonment has long been attempted. Contrasting results with radiocarbon dates around 2000 and 1670 yr BP have been reported, with implications for the development of the Mesoamerican centers of Cuicuilco and Teotihuacan. Here, we analyze radiocarbon dates and paleomagnetic data for the Xitle lava flows. New age estimates for the eruption are ...

  6. AMS ready for launch

    CERN Multimedia

    Katarina Anthony

    2011-01-01

    On 29 April, the Alpha Magnetic Spectrometer (AMS) will complete its long expedition to the International Space Station on board the space shuttle Endeavour. The Endeavour is set to lift off from NASA’s Kennedy Space Station at 15:47 EST (21:47 CET).   Samuel Ting, principal investigator for the AMS project, and Rolf Heuer, CERN Director-General, visit the Kennedy Space Centre before the AMS launch.  Courtesy of NASA and Kennedy Space Center. AMS is a CERN recognised experiment, created by an internal collaboration of 56 institutes. It will be the first large magnetic spectrometer to be used in space, and has been designed to function as an external module on the ISS. AMS will measure cosmic rays without atmospheric interference, allowing researchers on the ground to continue their search for dark matter and antimatter in the Universe. Data collected by AMS will be analysed in CERN’s new AMS Control Centre in Building 946 (due for completion in June 2011). The End...

  7. Extension of the Southern Hemisphere Atmospheric Radiocarbon Curve, 2120-850 years BP: Results from Tasmanian Huon Pine

    Energy Technology Data Exchange (ETDEWEB)

    Zimmerman, S R; P.Guilderson, T; Buckley, B M; Cook, E

    2010-02-12

    Decadal samples of dendrochronologically-dated pine (Lagorostrobos franklinii) from the Stanley River basin, Tasmania have been radiocarbon dated between 2120-850 yr BP. This data set overlaps and extends the current Southern Hemisphere record, which currently covers the period 110-995 yr BP. There is good agreement between the two records between 995-850 yr BP, between sample replicates and with consensus values for standards. As in the younger dataset, we find evidence for a distinct but variable offset between the southern hemisphere data and IntCal04; although this is likely due to real temporal variability in the interhemispheric offset, further work is planned to rule out possible laboratory or sample preparation differences.

  8. 78 FR 61446 - Fourteenth Meeting: RTCA Special Committee 222, Inmarsat AMS(R)S

    Science.gov (United States)

    2013-10-03

    ... Federal Aviation Administration Fourteenth Meeting: RTCA Special Committee 222, Inmarsat AMS(R)S AGENCY... RTCA Special Committee 222, Inmarsat AMS(R)S. SUMMARY: The FAA is issuing this notice to advise the public of the fourteenth meeting of the RTCA Special Committee 222, Inmarsat AMS(R)S DATES: The...

  9. 78 FR 8684 - Twelfth Meeting: RTCA Special Committee 222, Inmarsat AMS(R)S

    Science.gov (United States)

    2013-02-06

    ... Federal Aviation Administration Twelfth Meeting: RTCA Special Committee 222, Inmarsat AMS(R)S AGENCY... RTCA Special Committee 222, Inmarsat AMS(R)S. SUMMARY: The FAA is issuing this notice to advise the public of the twelfth meeting of the RTCA Special Committee 222, Inmarsat AMS(R)S. DATES: The...

  10. Associated terrestrial and marine fossils in the late-glacial Presumpscot Formation, southern Maine, USA, and the marine reservoir effect on radiocarbon ages

    Science.gov (United States)

    Thompson, W.B.; Griggs, C.B.; Miller, N.G.; Nelson, R.E.; Weddle, T.K.; Kilian, T.M.

    2011-01-01

    Excavations in the late-glacial Presumpscot Formation at Portland, Maine, uncovered tree remains and other terrestrial organics associated with marine invertebrate shells in a landslide deposit. Buds of Populus balsamifera (balsam poplar) occurred with twigs of Picea glauca (white spruce) in the Presumpscot clay. Tree rings in Picea logs indicate that the trees all died during winter dormancy in the same year. Ring widths show patterns of variation indicating responses to environmental changes. Fossil mosses and insects represent a variety of species and wet to dry microsites. The late-glacial environment at the site was similar to that of today's Maine coast. Radiocarbon ages of 14 tree samples are 11,907??31 to 11,650??5014C yr BP. Wiggle matching of dated tree-ring segments to radiocarbon calibration data sets dates the landslide occurrence at ca. 13,520+95/??20calyr BP. Ages of shells juxtaposed with the logs are 12,850??6514C yr BP (Mytilus edulis) and 12,800??5514C yr BP (Balanus sp.), indicating a marine reservoir age of about 1000yr. Using this value to correct previously published radiocarbon ages reduces the discrepancy between the Maine deglaciation chronology and the varve-based chronology elsewhere in New England. ?? 2011 University of Washington.

  11. AMS Prototyping Activities

    Science.gov (United States)

    Burleigh, Scott

    2008-01-01

    This slide presentation reviews the activity around the Asynchronous Message Service (AMS) prototype. An AMS reference implementation has been available since late 2005. It is aimed at supporting message exchange both in on-board environments and over space links. The implementation incoroporates all mandatory elements of the draft recommendation from July 2007: (1) MAMS, AMS, and RAMS protocols. (2) Failover, heartbeats, resync. (3) "Hooks" for security, but no cipher suites included in the distribution. The performance is reviewed, and a Benchmark latency test over VxWorks Message Queues is shown as histograms of a count vs microseconds per 1000-byte message

  12. AMS analyses at ANSTO

    Energy Technology Data Exchange (ETDEWEB)

    Lawson, E.M. [Australian Nuclear Science and Technology Organisation, Lucas Heights, NSW (Australia). Physics Division

    1998-03-01

    The major use of ANTARES is Accelerator Mass Spectrometry (AMS) with {sup 14}C being the most commonly analysed radioisotope - presently about 35 % of the available beam time on ANTARES is used for {sup 14}C measurements. The accelerator measurements are supported by, and dependent on, a strong sample preparation section. The ANTARES AMS facility supports a wide range of investigations into fields such as global climate change, ice cores, oceanography, dendrochronology, anthropology, and classical and Australian archaeology. Described here are some examples of the ways in which AMS has been applied to support research into the archaeology, prehistory and culture of this continent`s indigenous Aboriginal peoples. (author)

  13. CO2 Radiocarbon Analysis to Quantify Organic Contaminant Degradation, MNA, and Engineered Remediation Approaches

    Science.gov (United States)

    2014-12-18

    natural abundance CO2 radiocarbon content, CO2 flux measurements and a zone of influence (ZOI) model for well capture volume to quantify complete...Naval Research Laboratory Washington, DC 20375-5320 NRL/MR/6110--14-9539 CO2 Radiocarbon Analysis to Quantify Organic Contaminant Degradation, MNA...19b. TELEPHONE NUMBER (include area code) b. ABSTRACT c. THIS PAGE 18. NUMBER OF PAGES 17. LIMITATION OF ABSTRACT CO2 Radiocarbon Analysis to Quantify

  14. U-series and radiocarbon analyses of human and faunal remains from Wajak, Indonesia.

    Science.gov (United States)

    Storm, Paul; Wood, Rachel; Stringer, Chris; Bartsiokas, Antonis; de Vos, John; Aubert, Maxime; Kinsley, Les; Grün, Rainer

    2013-05-01

    Laser ablation U-series dating results on human and faunal bone fragments from Wajak, Indonesia, indicate a minimum age of between 37.4 and 28.5 ka (thousands of years ago) for the whole assemblage. These are significantly older than previously published radiocarbon estimates on bone carbonate, which suggested a Holocene age for a human bone fragment and a late Pleistocene age for a faunal bone. The analysis of the organic components in the faunal material show severe degradation and a positive δ(13)C ratio indicate a high degree of secondary carbonatisation. This may explain why the thermal release method used for the original age assessments yielded such young ages. While the older U-series ages are not in contradiction with the morphology of the Wajak human fossils or Javanese biostratigraphy, they will require a reassessment of the evolutionary relationships of modern human remains in Southeast Asia and Oceania. It can be expected that systematic direct dating of human fossils from this area will lead to further revisions of our understanding of modern human evolution.

  15. AMS-02 in Space: Physics Results

    CERN Document Server

    Tomassetti, Nicola

    2015-01-01

    The Alpha Magnetic Spectrometer (AMS-02) is a particle physics experiment designed to study origin and nature of Galactic Cosmic Rays (CRs) up to TeV energies from space. With its high sensitivity, long exposure and excellent identification capabilities, AMS is conducting a unique mission of fundamental physics research in space. To date, more than 60 billion CR events have been collected by AMS. The new results on CR leptons and the analysis and light-nuclei are presented and discussed. The new leptonic data indicate the existence of new sources of high-energy CR leptons, that may arise either by dark-matter particles annihilation or by nearby astrophysical sources of $e^{\\pm}$ pairs. Future data at higher energies and forthcoming measurements on the antiproton spectrum and the boron-to-carbon ratio will be crucial in providing the discrimination among the different scenario.

  16. I Am Canadian

    DEFF Research Database (Denmark)

    Goddard, Joe

    2011-01-01

    "I Am Canadian: Immigration and Multiculturalism in the True North" looks at Canadian immigration history from a contemporary point of view. The article scrutinizes recent discussions on dual nationality and what this may mean for Canadianness......."I Am Canadian: Immigration and Multiculturalism in the True North" looks at Canadian immigration history from a contemporary point of view. The article scrutinizes recent discussions on dual nationality and what this may mean for Canadianness....

  17. Can UK fossil fuel emissions be determined by radiocarbon measurements?

    Science.gov (United States)

    Wenger, Angelina; O'Doherty, Simon; Rigby, Matthew; Manning, Alistair; Palmer, Paul

    2016-04-01

    The GAUGE project evaluates different methods to estimate UK emissions. However, estimating carbon dioxide emissions as a result of fossil fuel burning is challenging as natural fluxes in and out of the atmosphere are very large. Radiocarbon (14C) measurements offer a way to specifically measure the amount of recently added carbon dioxide from fossil fuel burning. This is possible as, due to their age, all the radiocarbon in fossil fuels has decayed. Hence the amount of recently added CO2 from fossil fuel burning can be measured as a depletion of the 14C content in air. While this method has been successfully applied by several groups on a city or a regional scale, this is the first attempt at using the technique for a national emission estimate. Geographically the UK, being an island, is a good location for such an experiment. But are 14CO2 measurements the ideal solution for estimating fossil fuel emissions as they are heralded to be? Previous studies have shown that 14CO2emissions from the nuclear industry mask the 14C depletion caused by fossil fuel burning and result in an underestimation of the fossil fuel CO2. While this might not be a problem in certain regions around the world, many countries like the UK have a substantial nuclear industry. A correction for this enhancement from the nuclear industry can be applied but are invariably difficult as 14CO2emissions from nuclear power plants have a high temporal variability. We will explain how our sampling strategy was chosen to minimize the influence form the nuclear industry and why this proved to be challenging. In addition we present the results from our ground based measurements to show why trying to estimate national emissions using radiocarbon measurements was overambitious, and how practical the technique is for the UK in general.

  18. AMS in Phytonutrition

    Energy Technology Data Exchange (ETDEWEB)

    Dueker, S R; Buchholz, B A

    2003-08-26

    As public interest in phytonutrition continues to increase, the result will be an augmented demand for extensive phytochemical research. The fact that foods are inherently phytochemically complex dictates a need to apply scientific techniques, which can detect synergistic interaction among the many active principles and adjuvant substances in the plant, and furthermore, modify the activities of these components. As illustrated by the experiments discussed in this presentation, the advantages of AMS are unique and extensive. These advantages are best summarized by Dr. John Vogel, an originator of biological AMS experimentation: ''AMS brings (at least) three advantages to biochemical tracing: high sensitivity for finding low probability events or for use of physiologic-sized doses; small sample sizes for painless biopsies or highly specific biochemical separations; and reduction of overall radioisotope exposures, inventories, and waste streams.'' AMS opens the door to increased phytochemical tracing in humans to obtain biochemical data concerning human health at dietary relevant levels of exposure. AMS, thus, obviates the need for uncertain extrapolations from animal models, which express marginal relevance to human metabolism. The unparalleled capabilities and benefits of AMS will undoubtedly establish this particular MS technique as an important analytical tool in phytochemical research.

  19. 78 FR 31627 - Thirteenth Meeting: RTCA Special Committee 222, Inmarsat AMS(R)S.

    Science.gov (United States)

    2013-05-24

    ... Special Committee 222, Inmarsat AMS(R)S. AGENCY: Federal Aviation Administration (FAA), U.S. Department of Transportation (DOT). ACTION: Meeting Notice of RTCA Special Committee 222, Inmarsat AMS(R)S. SUMMARY: The FAA is..., Inmarsat AMS(R)S DATES: The meeting will be held June 10-11 from 9:00 a.m.-5:00 p.m. ADDRESSES: The...

  20. Dating mortars: three medieval Spanish architectures

    Directory of Open Access Journals (Sweden)

    Quirós Castillo, Juan Antonio

    2011-12-01

    Full Text Available One of the major issues in building archaeology is finding the age of elements and structures discovered. Mortars represent a class of material basically constituted by a mixture of different phases (i.e. binder, aggregates, water and are widely used for constructive uses and artworks. Current scientific literature regarding the possibility of accurate radiocarbon dating for mortars reports different and still contradictory results. In this study, a new protocol for radiocarbon dating of mortar developed at the Centre for Isotopic Research on Cultural and Environmental heritage (CIRCE is used to perform 14C measurements on archaeological mortars coming from three medieval architectures of northern Spain (two churches and the walls of a castle. Results observed will be discussed and compared with independent age estimations (i.e. radiocarbon dating performed on organic materials found in the same study site, archaeological analyses in order to frame experimental observations in the actual site knowledge by means of a multidisciplinary approach.Una de las principales problemáticas a las que se enfrenta la arqueología de la arquitectura es datar los elementos y las estructuras. Las argamasas son un tipo de material constituido por una mezcla de diferentes elementos (agregados, agua y empleadas en muchos tipos de construcciones. Los estudios realizados hasta la actualidad en torno a la posibilidad de realizar dataciones radiocarbónicas precisas han proporcionado resultados contradictorios. El objetivo de este artículo es el de presentar un nuevo protocolo para datar la arquitectura histórica desarrollado por el Centre for Isotopic Research on Cultural and Enviromental Heritage (CIRCE, basado en la realización de dataciones radiocarbónicas de argamasas a partir del análisis de tres arquitecturas medievales del norte del España, dos iglesias y la muralla de un castillo. Los resultados obtenidos han sido confrontados y comparados con otros

  1. Vertebral bomb radiocarbon suggests extreme longevity in white sharks.

    Science.gov (United States)

    Hamady, Li Ling; Natanson, Lisa J; Skomal, Gregory B; Thorrold, Simon R

    2014-01-01

    Conservation and management efforts for white sharks (Carcharodon carcharias) remain hampered by a lack of basic demographic information including age and growth rates. Sharks are typically aged by counting growth bands sequentially deposited in their vertebrae, but the assumption of annual deposition of these band pairs requires testing. We compared radiocarbon (Δ(14)C) values in vertebrae from four female and four male white sharks from the northwestern Atlantic Ocean (NWA) with reference chronologies documenting the marine uptake of (14)C produced by atmospheric testing of thermonuclear devices to generate the first radiocarbon age estimates for adult white sharks. Age estimates were up to 40 years old for the largest female (fork length [FL]: 526 cm) and 73 years old for the largest male (FL: 493 cm). Our results dramatically extend the maximum age and longevity of white sharks compared to earlier studies, hint at possible sexual dimorphism in growth rates, and raise concerns that white shark populations are considerably more sensitive to human-induced mortality than previously thought.

  2. Radiocarbon analysis of stratospheric CO2 retrieved from AirCore sampling

    NARCIS (Netherlands)

    Paul, Dipayan; Chen, Huilin; Been, Henk A.; Kivi, Rigel; Meijer, Harro A. J.

    2016-01-01

    Radiocarbon (C-14) is an important atmospheric tracer and one of the many used in the understanding of the global carbon budget, which includes the greenhouse gases CO2 and CH4. Measurement of radiocarbon in atmospheric CO2 generally requires the collection of large air samples (a few liters) from w

  3. Carbon 14 dating method; Methode de datation par le carbone 14

    Energy Technology Data Exchange (ETDEWEB)

    Fortin, Ph

    2000-07-01

    This document gives a first introduction to {sup 14}C dating as it is put into practice at the radiocarbon dating centre of Claude-Bernard university (Lyon-1 univ., Villeurbanne, France): general considerations and recalls of nuclear physics; the {sup 14}C dating method; the initial standard activity; the isotopic fractioning; the measurement of samples activity; the liquid-scintillation counters; the calibration and correction of {sup 14}C dates; the preparation of samples; the benzene synthesis; the current applications of the method. (J.S.)

  4. Forensic applications of {sup 14}C bomb-pulse dating

    Energy Technology Data Exchange (ETDEWEB)

    Zoppi, U. E-mail: ugo@ansto.gov.au; Skopec, Z.; Skopec, J.; Jones, G.; Fink, D.; Hua, Q.; Jacobsen, G.; Tuniz, C.; Williams, A

    2004-08-01

    After a brief review of the basics of {sup 14}C bomb-pulse dating, this paper presents two unique forensic applications. Particular attention is dedicated to the use of the {sup 14}C bomb-pulse to establish the time of harvest of illicit drugs such as heroin and opium. Preliminary measurements of {sup 14}C concentrations in milligram samples taken from seized drugs are presented. {sup 14}C bomb-pulse dating can determine whether drug distribution originates from stockpiles or recent manufacture, and support the action of law enforcement authorities against criminal organisations involved in drug trafficking. In addition, we describe the dating of wine vintages for a number of authenticated single label vintage red wines from the Barossa Valley - South Australia. Our results show that radiocarbon dating can be used to accurately determine wine vintages and therefore reveal the addition of unrelated materials of natural and synthetic origin.

  5. Study of radiocarbon dynamics of Baradla Cave, Hungary

    Science.gov (United States)

    Molnár, Mihály; Dezsö, Zoltán; Futo, Istvan; Siklósy, Zoltan; Jull, A. J. Timothy; Koltai, Gabriella

    2016-04-01

    Carbon isotope composition of speleothems and their parent drip water reflects the isotope composition of the atmospheric CO2, the soil and the host rock and can sometimes be influenced even by the cave atmosphere. Owing to the fact that 14C in the bedrock has long decayed, the bedrock derived carbon content of the seepage water can be considered as inactive or "dead carbon". The initial dead carbon proportion (dcp) of a stalagmite or tufa layer, caused by the incorporation of the inactive carbon, can be calculated with the help of the C-14 level differences between the contemporary atmosphere and the formed stone carbonate. The revolutionary technological advances of 14C (AMS) have brought the possibility of analysing 14C dynamics of karst systems due to the small amount of demanded material. The Baradla-Domica Cave is the largest cave of Gömör-Torna Karst, a karst area situated in the northeast of Hungary, and located on the Slovakian-Hungarian borderland. The approximately 26 km long cave is a typical example of multi-level speleogenesis. As a case study we have investigated several recent (age < 50 years) and older (age about 10-11 kyrs) stalagmites and recent drip water, some freshwater tufa samples and the recent cave air carbon-dioxide of the Baradla-cave to study the carbon dynamics and dead carbon level there. According four modern stalagmites (formed 1991-2004) the current dcp is very small in Baradla Cave (3-7%). Stalagmites deposited in Holocene (U/Th dated) were also characterized by very small dead carbon contents (1-11% dcp). Outside the cave a dpc about 20-25% was found in a freshwater tufa sample. This relatively low dead carbon content might be either explained by the thinness of the limestone bedrock above (56-80 m) or the relatively fast infiltration conditions, or their combined effect. Cave air is enriched in CO2 (2-5 times higher than in natural air, not homogenous) but the source of this surplus CO2 is not the limestone according its

  6. New and revised 14C dates for Hawaiian surface lava flows: Paleomagnetic and geomagnetic implications

    Science.gov (United States)

    Pressline, N.; Trusdell, F.A.; Gubbins, David

    2009-01-01

    Radiocarbon dates have been obtained for 30 charcoal samples corresponding to 27 surface lava flows from the Mauna Loa and Kilauea volcanoes on the Island of Hawaii. The submitted charcoal was a mixture of fresh and archived material. Preparation and analysis was undertaken at the NERC Radiocarbon Laboratory in Glasgow, Scotland, and the associated SUERC Accelerator Mass Spectrometry facility. The resulting dates range from 390 years B.P. to 12,910 years B.P. with corresponding error bars an order of magnitude smaller than previously obtained using the gas-counting method. The new and revised 14C data set can aid hazard and risk assessment on the island. The data presented here also have implications for geomagnetic modelling, which at present is limited by large dating errors. Copyright 2009 by the American Geophysical Union.

  7. Hydrological and climatological controls on radiocarbon concentrations in a tropical stalagmite

    Science.gov (United States)

    Lechleitner, Franziska A.; Baldini, James U. L.; Breitenbach, Sebastian F. M.; Fohlmeister, Jens; McIntyre, Cameron; Goswami, Bedartha; Jamieson, Robert A.; van der Voort, Tessa S.; Prufer, Keith; Marwan, Norbert; Culleton, Brendan J.; Kennett, Douglas J.; Asmerom, Yemane; Polyak, Victor; Eglinton, Timothy I.

    2016-12-01

    Precisely-dated stalagmites are increasingly important archives for the reconstruction of terrestrial paleoclimate at very high temporal resolution. In-depth understanding of local conditions at the cave site and of the processes driving stalagmite deposition is of paramount importance for interpreting proxy signals incorporated in stalagmite carbonate. Here we present a sub-decadally resolved dead carbon fraction (DCF) record for a stalagmite from Yok Balum Cave (southern Belize). The record is coupled to parallel stable carbon isotope (δ13C) and U/Ca measurements, as well as radiocarbon (14C) measurements from soils overlying the cave system. Using a karst carbon cycle model we disentangle the importance of soil and karst processes on stalagmite DCF incorporation, revealing a dominant host rock dissolution control on total DCF. Covariation between DCF, δ13C, and U/Ca indicates that karst processes are a common driver of all three parameters, suggesting possible use of δ13C and trace element ratios to independently quantify DCF variability. A statistically significant multi-decadal lag of variable length exists between DCF and reconstructed solar activity, suggesting that solar activity influenced regional precipitation in Mesoamerica over the past 1500 years, but that the relationship was non-static. Although the precise nature of the observed lag is unclear, solar-induced changes in North Atlantic oceanic and atmospheric dynamics may play a role.

  8. IA, I AM

    DEFF Research Database (Denmark)

    Munk, Timme Bisgaard; Mørk, Kristian

    2004-01-01

    Hvad er informationsarkitektur? Mørk & Munk gennemgår de forskellige metaforiske konstruktioner af begrebet og kommer med deres helt egen selvstændige definition. Informationsarkitektur er en samtale, strukturation, en klassifikationskamp og et konceptuelt blend. Læs hvorfor i dette working paper...... om et af de meste centrale begreber videnssamfundet. For nu er vi alle informationsarkitekter: IA, I AM....

  9. BCal: an on-line Bayesian radiocarbon calibration tool

    Directory of Open Access Journals (Sweden)

    Caitlin E. Buck

    1999-09-01

    Full Text Available In this paper we describe newly launched software for on-line Bayesian calibration of archaeological radiocarbon determinations. The software is known as BCal and we invite members of the world-wide archaeological research community to use it should they so wish. All that is required to gain access to the software is a computer connected to the Internet with a modern World-wide Web browser (of the sort you are probably using to read this. BCal does not require access to any additional 'Plug-ins' on your machine. Since the computations needed to obtain the calibrations are undertaken on the BCal server, if you have enough computer power to run your World-wide Web browser you have enough power to use BCal.

  10. Radiocarbon Releases from the 2011 Fukushima Nuclear Accident

    DEFF Research Database (Denmark)

    Xu, Sheng; Cook, Gordon T.; Cresswell, Alan J.

    2016-01-01

    Radiocarbon activities were measured in annual tree rings for the years 2009 to 2015 from Japanese cedar trees (Cryptomeria japonica) collected at six sites ranging from 2.5-38 km northwest and north of the Fukushima Dai-ichi nuclear power plant. The 14C specific activity varied from 280.4 Bq kg-1...... C in 2010 to 226.0 Bq kg-1 C in 2015. The elevated 14C activities in the 2009 and 2010 rings confirmed 14C discharges during routine reactor operations, whereas those activities that were indistinguishable from background in 2012-2015 coincided with the permanent shutdown of the reactors after...... the excess 14C activities is negligible compared to the dose from natural/nuclear weapons sources....

  11. Age-dating of rockslides: Methods and limitations

    Science.gov (United States)

    Ostermann, M.; Sanders, D.; Prager, C.

    2009-04-01

    Age-dating of deposits of catastrophic rockslides is prerequisite to unravel the potential relation between the frequency of mass-wasting events with climatic change or earthquakes. In the Alps, about 250 rockslides exceeding 106 m3 in volume are known, but the age as yet is determined only for a comparatively small number of events. For age determination of rockslide events, different methods are available (e. g. Lang et al., 1999). Radiocarbon Dating In the past few decades, rockslide deposits commonly were proxy-dated by 14C age determination of organic remnants preserved (a) in glacial, fluvio-glacial sediments overridden by the rockslide, (b) within the rockslide mass, or (c) in rockslide-dammed backwater deposits or lakes situated atop the rockslide mass. In each case, the 14C age provides a different constraint on the age of the rockslide event: in case (a), the 14C age represents a maximum age of the event; in case (b), which is quite rare, the 14C age is generally considered as a good proxy of the event age; in case (c) the 14C age represents a minimum age for the rockslide event. Unfortunately, radiocarbon dating often cannot be applied because of absence of suited deposits or exposures thereof, lack of organic remnants or of remnants suited for age-dating, and/or because determined 14C ages are substantially biased. Optically Stimulated Luminescence (OSL) Proxy-dating of rockslide events by OSL can be applied to silt- to sand-sized quartzose sediments present (a) directly below, (b) within, or (c) above/laterally aside a rockslide mass. For each case (a) to (c), the determined ages are subject to the same constraints as outlined for radiocarbon dating. Unfortunately, situations allowing for application of OSL to rockslide event dating are comparatively rare, and the resulting ages tend to have a wide error range. Surface Exposure Dating with cosmogenic radionuclides Surface exposure ages can be determined for rock samples taken from the sliding planes at

  12. The Sea Peoples, from cuneiform tablets to carbon dating.

    Directory of Open Access Journals (Sweden)

    David Kaniewski

    Full Text Available The 13(th century BC witnessed the zenith of the Aegean and Eastern Mediterranean civilizations which declined at the end of the Bronze Age, ∼3200 years ago. Weakening of this ancient flourishing Mediterranean world shifted the political and economic centres of gravity away from the Levant towards Classical Greece and Rome, and led, in the long term, to the emergence of the modern western civilizations. Textual evidence from cuneiform tablets and Egyptian reliefs from the New Kingdom relate that seafaring tribes, the Sea Peoples, were the final catalyst that put the fall of cities and states in motion. However, the lack of a stratified radiocarbon-based archaeology for the Sea People event has led to a floating historical chronology derived from a variety of sources spanning dispersed areas. Here, we report a stratified radiocarbon-based archaeology with anchor points in ancient epigraphic-literary sources, Hittite-Levantine-Egyptian kings and astronomical observations to precisely date the Sea People event. By confronting historical and science-based archaeology, we establish an absolute age range of 1192-1190 BC for terminal destructions and cultural collapse in the northern Levant. This radiocarbon-based archaeology has far-reaching implications for the wider Mediterranean, where an elaborate network of international relations and commercial activities are intertwined with the history of civilizations.

  13. Online coupling of pure O{sub 2} thermo-optical methods – {sup 14}C AMS for source apportionment of carbonaceous aerosols

    Energy Technology Data Exchange (ETDEWEB)

    Agrios, Konstantinos [Department of Chemistry and Biochemistry, University of Bern, Bern (Switzerland); Oeschger Centre for Climate Change Research, University of Bern, Bern (Switzerland); Paul Scherrer Institute, Villigen (Switzerland); Salazar, Gary [Department of Chemistry and Biochemistry, University of Bern, Bern (Switzerland); Oeschger Centre for Climate Change Research, University of Bern, Bern (Switzerland); Zhang, Yan-Lin; Uglietti, Chiara [Department of Chemistry and Biochemistry, University of Bern, Bern (Switzerland); Oeschger Centre for Climate Change Research, University of Bern, Bern (Switzerland); Paul Scherrer Institute, Villigen (Switzerland); Battaglia, Michael [Department of Chemistry and Biochemistry, University of Bern, Bern (Switzerland); Oeschger Centre for Climate Change Research, University of Bern, Bern (Switzerland); Luginbühl, Marc [Department of Chemistry and Biochemistry, University of Bern, Bern (Switzerland); Ciobanu, Viorela Gabriela [Paul Scherrer Institute, Villigen (Switzerland); Vonwiller, Matthias [Department of Chemistry and Biochemistry, University of Bern, Bern (Switzerland); Oeschger Centre for Climate Change Research, University of Bern, Bern (Switzerland); Paul Scherrer Institute, Villigen (Switzerland); Szidat, Sönke, E-mail: szidat@dcb.unibe.ch [Department of Chemistry and Biochemistry, University of Bern, Bern (Switzerland); Oeschger Centre for Climate Change Research, University of Bern, Bern (Switzerland)

    2015-10-15

    This paper reports on novel separation methods developed for the direct determination of {sup 14}C in organic carbon (OC) and elemental carbon (EC), two sub-fractions of total carbon (TC) of atmospheric air particulate matter. Until recently, separation of OC and EC has been performed off-line by manual and time-consuming techniques that relied on the collection of massive CO{sub 2} fractions. We present here two on-line hyphenated techniques between a Sunset OC/EC analyzer and a MICADAS (MIni radioCArbon DAting System) accelerator mass spectrometer (AMS) equipped with a gas ion source. The first implementation facilitates the direct measurement in the low sample size range (<10 μg C) with high throughput on a routine basis, while the second explores the potential for a continuous-flow real-time CO{sub 2} gas feed into the ion source. The performance achieved with reference materials and real atmospheric samples will be discussed to draw conclusions on the improvement offered in the field of {sup 14}C aerosol source apportionment.

  14. Radiocarbon chronology and environment of woolly mammoth ( Mammuthus primigenius Blum.) in northern Asia: results and perspectives

    Science.gov (United States)

    Kuzmin, Yaroslav V.; Orlova, Lyobov A.

    2004-12-01

    This paper reviews the history of the woolly mammoth ( Mammuthus primigenius Blum.) in Siberia and adjacent northern Asia. The particular emphases are the chronology and environment of mammoth existence and extinction, based on about 530 radiocarbon dates from about 230 localities with mammoth remains and palaeoenvironmental records of the last 50,000 years. Until ca. 12,000 radiocarbon years ago (BP), mammoths inhabited all of northern Asia, from the High Arctic to southern Siberia and northeastern China. Since ca. 12,000 BP, mammoth disappeared from major parts of Siberia and adjacent northern Asia, and survived mainly in the Arctic regions of Siberia, north of 69° northern latitude. However, recently, it was found that some mammoth populations continued to exist in central and southern Western Siberia until ca. 11,100-10,200 BP. 'Normal' size mammoths became extinct in mainland Siberia at the Pleistocene-Holocene boundary, ca. 9700 BP. On Wrangel Island in the High Arctic, small-sized mammoths survived into the Middle-Late Holocene, ca. 7700-3700 BP. Compared with previous studies, it is now possible to reveal the complex nature of the process of final mammoth extinction in Siberia, with some small populations surviving outside of the Arctic until ca. 10,000 BP. The extinction of mammoth was most probably caused by a combination of factors, such as global warming in the Late Glacial (since ca. 15,000 BP) and the disintegration of landscapes suitable for mammoths throughout the Upper Pleistocene, such as light forests with vast open spaces occupied by meadows and forest tundra. The expansion of forest vegetation after the Last Glacial Maximum in Siberia, including its northeastern part, created unsuitable habitats for herbivorous megafauna, especially for mammoths. However, the Holocene environment of Wrangel Island was not of 'glacial' type and this requires further studies. The relationship between mammoths and Upper Palaeolithic humans is also considered. The

  15. Date Rape (For Teens)

    Science.gov (United States)

    ... Loss Surgery? A Week of Healthy Breakfasts Shyness Date Rape KidsHealth > For Teens > Date Rape A A ... Rape en español Violaciones durante citas What Is Date Rape? When people think of rape , they might ...

  16. Otoliths as recorders of palaeoenvironments: comparison of radiocarbon age and isoleucine epimerization in Pleistocene golden perch `Macquaria ambigua` otoliths from Willandra Lakes

    Energy Technology Data Exchange (ETDEWEB)

    Kalish, J.M.; Pritchard, C. [Australian National Univ., Canberra, ACT (Australia); Miller, G.H.; Rosewater, A. [Colorado Univ., Boulder, CO (United States). Dept. of Geological Sciences; Tuniz, C.; Lawson, E. [Australian Nuclear Science and Technology Organisation, Lucas Heights, NSW (Australia)

    1997-12-31

    Fish otoliths form by the accretion of layers of calcium carbonate and organic-rich material that often form distinctive layers over time scales ranging from days to years. These layers are not resorbed during the life of the fish and have potential to provide data relevant to both the biology of the fish and the environment to which the fish has been exposed. Environmental variability based on otoliths can be estimated through measures of stable oxygen isotopes, trace elements, and the widths of both daily and annual increments. Although otoliths can be dated based on measurement of radiocarbon by accelerator mass spectrometry this method is relatively expensive. An alternative method for dating golden perch otoliths is based on measurements of isoleucine D/L ratios. Miller and Rosewater (1995) demonstrated that golden perch otoliths are near a perfect closed system for racemization and that otoliths have potential of dating surrounding sediments older than 100 ka. Despite the suitability of these structures for racemization measurements, many of collections of Pleistocene otoliths from Willandra Lakes are not appropriate for determination of sample age. Most otoliths sampled in the region have been derived from surface collections, while it is recommended that samples should have been buried at least 1 m during most of their history. Therefore, the majority of existing otolith collections are not appropriate for geochronology or palaeothermometry. Nevertheless, when used in conjunction with radiocarbon dates, racemization data may be of value in assessing the relationship among otoliths in an assemblage. Radiocarbon ages and isoleucine D/L ratios were determined for 30 otoliths collected from Willandra Lakes. The rostrum of each otolith was analysed for D/L ratios and a portion of the posterior of the same otolith was analysed for radiocarbon by accelerator mass spectrometry. Sample weights for both analyses ranged from 14.0 to 25.6 mg. The central portion of the

  17. AMS of the Minor Plutonium Isotopes.

    Science.gov (United States)

    Steier, P; Hrnecek, E; Priller, A; Quinto, F; Srncik, M; Wallner, A; Wallner, G; Winkler, S

    2013-01-01

    VERA, the Vienna Environmental Research Accelerator, is especially equipped for the measurement of actinides, and performs a growing number of measurements on environmental samples. While AMS is not the optimum method for each particular plutonium isotope, the possibility to measure (239)Pu, (240)Pu, (241)Pu, (242)Pu and (244)Pu on the same AMS sputter target is a great simplification. We have obtained a first result on the global fallout value of (244)Pu/(239)Pu = (5.7 ± 1.0) × 10(-5) based on soil samples from Salzburg prefecture, Austria. Furthermore, we suggest using the (242)Pu/(240)Pu ratio as an estimate of the initial (241)Pu/(239)Pu ratio, which allows dating of the time of irradiation based solely on Pu isotopes. We have checked the validity of this estimate using literature data, simulations, and environmental samples from soil from the Salzburg prefecture (Austria), from the shut down Garigliano Nuclear Power Plant (Sessa Aurunca, Italy) and from the Irish Sea near the Sellafield nuclear facility. The maximum deviation of the estimated dates from the expected ages is 6 years, while relative dating of material from the same source seems to be possible with a precision of less than 2 years. Additional information carried by the minor plutonium isotopes may allow further improvements of the precision of the method.

  18. May {sup 14}C be used to date contemporary art?

    Energy Technology Data Exchange (ETDEWEB)

    Fedi, M.E., E-mail: fedi@fi.infn.it [INFN Sezione di Firenze, Via Sansone 1, 50019 Sesto Fiorentino (Italy); Caforio, L. [INFN Sezione di Firenze, Via Sansone 1, 50019 Sesto Fiorentino (Italy); Dipartimento di Fisica, Universita di Ferrara, Via Saragat 1, 44100 Ferrara (Italy); Mando, P.A. [INFN Sezione di Firenze, Via Sansone 1, 50019 Sesto Fiorentino (Italy); Dipartimento di Fisica e Astronomia, Universita di Firenze, Via Sansone 1, 50019 Sesto Fiorentino (Italy); Petrucci, F. [Dipartimento di Fisica, Universita di Ferrara, Via Saragat 1, 44100 Ferrara (Italy); INFN Sezione di Ferrara, Via Saragat 1, 44100 Ferrara (Italy); Taccetti, F. [INFN Sezione di Firenze, Via Sansone 1, 50019 Sesto Fiorentino (Italy)

    2013-01-15

    The use of radiocarbon in forensics is by now widespread, thanks to the so-called bomb peak, which makes it possible to perform high-precision dating. Since 1955, {sup 14}C concentration in the atmosphere had strongly increased due to nuclear explosions, reaching its maximum value in 1963-1965. After the Nuclear Test Ban Treaty, {sup 14}C started to decrease as a consequence of the exchanges between atmosphere and the other natural carbon reservoirs. Nowadays, it is still slightly above the pre-bomb value. The work presented in this paper is based on the idea of exploiting the bomb peak to 'precisely' date works of contemporary art, with the aim at identifying possible fakes. We analysed two kinds of materials from the 20th century: newspapers and painting canvases. Newspaper samples were taken because they might in principle be considered to represent dated samples (considering the date on the issues). Our data (28 samples) show a trend similar to atmospheric data in the literature, although with some differences; the paper peak is flatter and shifted towards more recent years (about five years) with respect to the atmospheric data. This can be explained by taking paper manufacturing processes into account. As to the canvas samples, the measured {sup 14}C concentrations were generally reasonably consistent with the expected concentrations (based on the year on the paintings). However, this does not indicate that the interpretation of the results is simpler and more straightforward. Obviously, we only measure the {sup 14}C concentration of the fibre used for the canvas, which does not necessarily measure the date the painting was manufactured. In this paper, sample preparation and experimental results will be discussed, in order to show the potential as well as the limitations of radiocarbon to date contemporary art.

  19. May 14C be used to date contemporary art?

    Science.gov (United States)

    Fedi, M. E.; Caforio, L.; Mandò, P. A.; Petrucci, F.; Taccetti, F.

    2013-01-01

    The use of radiocarbon in forensics is by now widespread, thanks to the so-called bomb peak, which makes it possible to perform high-precision dating. Since 1955, 14C concentration in the atmosphere had strongly increased due to nuclear explosions, reaching its maximum value in 1963-1965. After the Nuclear Test Ban Treaty, 14C started to decrease as a consequence of the exchanges between atmosphere and the other natural carbon reservoirs. Nowadays, it is still slightly above the pre-bomb value. The work presented in this paper is based on the idea of exploiting the bomb peak to “precisely” date works of contemporary art, with the aim at identifying possible fakes. We analysed two kinds of materials from the 20th century: newspapers and painting canvases. Newspaper samples were taken because they might in principle be considered to represent dated samples (considering the date on the issues). Our data (28 samples) show a trend similar to atmospheric data in the literature, although with some differences; the paper peak is flatter and shifted towards more recent years (about five years) with respect to the atmospheric data. This can be explained by taking paper manufacturing processes into account. As to the canvas samples, the measured 14C concentrations were generally reasonably consistent with the expected concentrations (based on the year on the paintings). However, this does not indicate that the interpretation of the results is simpler and more straightforward. Obviously, we only measure the 14C concentration of the fibre used for the canvas, which does not necessarily measure the date the painting was manufactured. In this paper, sample preparation and experimental results will be discussed, in order to show the potential as well as the limitations of radiocarbon to date contemporary art.

  20. Age validation of quillback rockfish (Sebastes maliger) using bomb radiocarbon

    Energy Technology Data Exchange (ETDEWEB)

    Kerr, L A; Andrews, A H; Munk, K; Coale, K H; Frantz, B R; Cailliet, G M; Brown, T A

    2005-01-05

    Rockfishes (Sebastes spp.) support one of the most economically important fisheries of the Pacific Northwest and it is essential for sustainable management that age estimation procedures be validated for these species. Atmospheric testing of thermonuclear devices during the 1950s and 1960s created a global radiocarbon ({sup 14}C) signal in the ocean environment that scientists have identified as a useful tracer and chronological marker in natural systems. In this study, we first demonstrated that fewer samples are necessary for age validation using the bomb-generated {sup 14}C signal by emphasizing the utility of the time-specific marker created by the initial rise of bomb-{sup 14}C. Second, the bomb-generated {sup 14}C signal retained in fish otoliths was used to validate the age and age estimation methodology of the quillback rockfish (Sebastes maliger) in the waters of southeast Alaska. Radiocarbon values from the first year's growth of quillback rockfish otoliths were plotted against estimated birth year producing a {sup 14}C time series spanning 1950 to 1985. The initial rise of bomb-{sup 14}C from pre-bomb levels ({approx} -90 {per_thousand}) occurred in 1959 {+-} 1 year and {sup 14}C levels rose relatively rapidly to peak {Delta}{sup 14}C values in 1967 (+105.4 {per_thousand}), with a subsequent declining trend through the end of the record in 1985 (+15.4 {per_thousand}). The agreement between the year of initial rise of {sup 14}C levels from the quillback rockfish record and the chronometer determined for the waters of southeast Alaska from yelloweye rockfish (S. ruberrimus) otoliths validated the ageing methodology for the quillback rockfish. The concordance of the entire quillback rockfish {sup 14}C record with the yelloweye rockfish time series demonstrated the effectiveness of this age validation technique, confirmed the longevity of the quillback rockfish up to a minimum of 43 years, and strongly supports higher age estimates of up to 90 years.

  1. On the Implementation of AM/AM AM/PM Behavioral Models in System Level Simulation

    NARCIS (Netherlands)

    Shen, Y.; Tauritz, J.L.

    2003-01-01

    The use of nonlinear device behavioral models offers an economical way of simulating the performance of complex communication systems. A concrete method for implementing the AM/AM AM/PM behavioral model in system level simulation using ADS is developed. This method seamlessly tansfers the data from

  2. Kepler observations of Am stars

    DEFF Research Database (Denmark)

    Balona, L. A.; Ripepi, V.; Cantanzaro, G.

    2011-01-01

    We present an analysis of high-resolution spectra for two pulsating Am stars in the Kepler field. The stellar parameters derived in this way are important because parameters derived from narrow-band photometry may be affected by the strong metal lines in these stars. We analyse the Kepler time...... series of ten known Am stars and find that six of them clearly show δ Scuti pulsations. The other four appear to be non-pulsating. We derive fundamental parameters for all known pulsating Am stars from ground-based observations and also for the Kepler Am stars to investigate the location...... of the instability strip for pulsating Am stars. We find that there is not much difference between the Am-star instability strip and the δ Scuti instability strip. We find that the observed location of pulsating Am stars in the HR diagram does not agree with the location predicted from diffusion calculations. Based...

  3. Radiocarbon Releases from the 2011 Fukushima Nuclear Accident

    Science.gov (United States)

    Xu, Sheng; Cook, Gordon T.; Cresswell, Alan J.; Dunbar, Elaine; Freeman, Stewart P. H. T.; Hou, Xiaolin; Jacobsson, Piotr; Kinch, Helen R.; Naysmith, Philip; Sanderson, David C. W.; Tripney, Brian G.

    2016-11-01

    Radiocarbon activities were measured in annual tree rings for the years 2009 to 2015 from Japanese cedar trees (Cryptomeria japonica) collected at six sites ranging from 2.5–38 km northwest and north of the Fukushima Dai-ichi nuclear power plant. The 14C specific activity varied from 280.4 Bq kg‑1 C in 2010 to 226.0 Bq kg‑1 C in 2015. The elevated 14C activities in the 2009 and 2010 rings confirmed 14C discharges during routine reactor operations, whereas those activities that were indistinguishable from background in 2012–2015 coincided with the permanent shutdown of the reactors after the accident in 2011. High-resolution 14C analysis of the 2011 ring indicated 14C releases during the Fukushima accident. The resulted 14C activity decreased with increasing distance from the plant. The maximum 14C activity released during the period of the accident was measured 42.4 Bq kg‑1 C above the natural ambient 14C background. Our findings indicate that, unlike other Fukushima-derived radionuclides, the 14C released during the accident is indistinguishable from ambient background beyond the local environment (~30 km from the plant). Furthermore, the resulting dose to the local population from the excess 14C activities is negligible compared to the dose from natural/nuclear weapons sources.

  4. An effective method of UV-oxidation of dissolved organic carbon in natural waters for radiocarbon analysis by accelerator mass spectrometry

    Science.gov (United States)

    Xue, Yuejun; Ge, Tiantian; Wang, Xuchen

    2015-12-01

    Radiocarbon (14C) measurement of dissolved organic carbon (DOC) is a very powerful tool to study the sources, transformation and cycling of carbon in the ocean. The technique, however, remains great challenges for complete and successful oxidation of sufficient DOC with low blanks for high precision carbon isotopic ratio analysis, largely due to the overwhelming proportion of salts and low DOC concentrations in the ocean. In this paper, we report an effective UV-Oxidation method for oxidizing DOC in natural waters for radiocarbon analysis by accelerator mass spectrometry (AMS). The UV-oxidation system and method show 95%±4% oxidation efficiency and high reproducibility for DOC in both river and seawater samples. The blanks associated with the method was also low (about 3 µg C) that is critical for 14C analysis. As a great advantage of the method, multiple water samples can be oxidized at the same time so it reduces the sample processing time substantially compared with other UV-oxidation method currently being used in other laboratories. We have used the system and method for 14C studies of DOC in rivers, estuaries, and oceanic environments and have received promise results.

  5. Implications of a Bayesian radiocarbon calibration of colonization ages for mammalian megafauna in glaciated New York State after the Last Glacial Maximum

    Science.gov (United States)

    Feranec, Robert S.; Kozlowski, Andrew L.

    2016-03-01

    To understand what factors control species colonization and extirpation within specific paleoecosystems, we analyzed radiocarbon dates of megafaunal mammal species from New York State after the Last Glacial Maximum. We hypothesized that the timing of colonization and extirpation were both driven by access to preferred habitat types. Bayesian calibration of a database of 39 radiocarbon dates shows that caribou (Rangifer tarandus) were the first colonizers, then mammoth (Mammuthus sp.), and finally American mastodon (Mammut americanum). The timing of colonization cannot reject the hypothesis that colonizing megafauna tracked preferred habitats, as caribou and mammoth arrived when tundra was present, while mastodon arrived after boreal forest was prominent in the state. The timing of caribou colonization implies that ecosystems were developed in the state prior to 16,000 cal yr BP. The contemporaneous arrival of American mastodon with Sporormiella spore decline suggests the dung fungus spore is not an adequate indicator of American mastodon population size. The pattern in the timing of extirpation is opposite to that of colonization. The lack of environmental changes suspected to be ecologically detrimental to American mastodon and mammoth coupled with the arrival of humans shortly before extirpation suggests an anthropogenic cause in the loss of the analyzed species.

  6. Systematic Uncertainties of Glacial Chronologies Based on Surface Exposure Dating

    Science.gov (United States)

    Ilgner, J.; Zech, R.; Baechtiger, C.; Kubik, P. W.; Veit, H.

    2008-12-01

    Surface exposure dating using terrestrial cosmogenic nuclides provides the opportunity to establish glacial chronologies in semi-arid high mountain regions, where the lack of organic material for radiocarbon dating has limited our knowledge about the timing and the causes of glacial advances so far. However, several scaling systems and calculation schemes exist. This can result in significant systematic uncertainties, particularly at high altitudes as e.g. in the Central Andes. We present and discuss previously published exposure ages from Bolivia and Argentina in order to illustrate the extent of the current uncertainties. It is neither possible to unambiguously determine whether the local Last Glacial Maximum (local LGM) in the tropics occurred in-phase with or predated the global LGM, nor can the subsequent Late Glacial stages be dated accurately enough to infer temperature or precipitation changes at millennial-scale timescales. We then also present new results from the Tres Lagunas in the Sierra de Santa Victoria, NW Argentina. There we can compare our glacial exposure age chronology with bracketing radiocarbon ages from lake sediments. The Tres Lagunas may thus serve as a high-altitude calibration site for 10Be dating. Paleoclimatically, we conclude that glacial deposits in NW-Argentina document glacial advances in-phase with the global LGM, but that the prominent moraines there date to the Late Glacial. This coincides with the well-documented intensification and/or southward shift of the tropical circulation and reflects the strong precipitation-sensitivity of glaciers in arid and semi-arid environments.

  7. {sup 14}C chronology of the oldest Scandinavian church in use. An AMS/PIXE study of lime lump carbonate in the mortar

    Energy Technology Data Exchange (ETDEWEB)

    Lindroos, Alf, E-mail: alf.lindroos@abo.fi [Geology and Mineralogy, Department of Natural Sciences, Åbo Akademi University (Finland); Art History, Faculty of Art, Åbo Akademi University (Finland); Ranta, Heikki [Diocese of Lund, Church of Sweden (Sweden); Heinemeier, Jan [AMS " 1" 4C Dating Laboratory, Department of Physics and Astronomy, University of Aarhus (Denmark); Lill, Jan-Olof [Accelerator Laboratory, Turku PET Centre, Åbo Akademi University (Finland)

    2014-07-15

    Mortar dating was applied to newly revealed, original mortar in the church of Dalby in Scania, southern Sweden which is considered to be the oldest still standing church in Scandinavia. Small white lime lumps were sampled by chipping from the supporting pillars in the interior of the church. Special emphasis was in sampling lime lumps because the church is situated in the Scania limestone area and aggregate limestone contamination was anticipated in the bulk mortars. Earlier studies have, however, shown that lime lumps do not contain aggregate material but only possible limestone rests from incomplete calcination. The sampled material was prepared for radiocarbon AMS dating. The carbonate in the lime lumps was hydrolyzed according to the sequential leaching technique developed for the Århus {sup 14}C laboratory in Denmark. Prior to the hydrolysis the lime lumps were examined for dead-carbon contamination using a stereo microscope and cathodoluminescence. The lime lumps displayed heterogeneous carbonate luminescence. This is, however, common and it was not considered a problem because carbonate growth in changing pH/Eh conditions often leads to changing luminescence colors. Two lumps had little dead carbon contamination and an early second millennium {sup 14}C signature. One lump, however, seemed to be heavily contaminated with dead carbon. Since the sample passed the microscopic screening, the leftovers of the lump was subjected to PIXE analysis and compared with the other two lumps. The well-defined, early 2nd millennium {sup 14}C age of the lime lumps of this particular church is an important contribution to the discussion on stone church chronology in Scandinavia.

  8. Understanding Teen Dating Violence

    Science.gov (United States)

    ... Ennett ST, Cance JD, Bauman KE, Bowling JM. Assessing the effects of Families for Safe Dates, a family-based teen dating abuse prevention program. Journal of Adolescent Health 2012; 51:349-356. ...

  9. Advances in the graphitization protocol at the Radiocarbon Laboratory of the Universidade Federal Fluminense (LAC-UFF) in Brazil

    Energy Technology Data Exchange (ETDEWEB)

    Macario, Kita D., E-mail: kitamacario@gmail.com [Departamento de Física, Instituto deFísica, Universidade Federal Fluminense, Campus da Praia Vermelha, Av. Gal. Milton Tavares de Souza s/n°, Niterói, RJ, 24210-346 (Brazil); Oliveira, Fabiana M. [Departamento de Física, Instituto deFísica, Universidade Federal Fluminense, Campus da Praia Vermelha, Av. Gal. Milton Tavares de Souza s/n°, Niterói, RJ, 24210-346 (Brazil); Carvalho, Carla [Departamento de Geoquímica, Instituto de Química, Universidade Federal Fluminense, Campus do Valonguinho, Outeiro São João Batista, s/n°, Niterói, RJ, 24020-150 (Brazil); Santos, Guaciara M.; Xu, Xiaomei [Department of Earth System Science, B321 Croul Hall, University of California Irvine, Irvine, CA, 92697-3100 (United States); Chanca, Ingrid S.; Alves, Eduardo Q.; Jou, Renata M.; Oliveira, Maria Isabela; Pereira, Bruna B.; Moreira, Vinicius; Muniz, Marcelo C.; Linares, Roberto; Gomes, Paulo Roberto Silveira; Meigikos dos Anjos, Roberto [Departamento de Física, Instituto deFísica, Universidade Federal Fluminense, Campus da Praia Vermelha, Av. Gal. Milton Tavares de Souza s/n°, Niterói, RJ, 24210-346 (Brazil); and others

    2015-10-15

    In this paper, we summarize the sample preparation methods currently used at the Radiocarbon Laboratory of the Universidade Federal Fluminense (LAC-UFF) in Brazil. We also report on a series of results with regards to the graphitization protocol. Tests with different temperatures and baking times were performed, and carbon stable isotope ratios of graphite were measured by an EA–IRMS (elemental analyzer coupled with an isotopic ratio mass spectrometer) to infer the completeness of the graphitization reaction. We monitored the muffle furnace temperature using an independent thermocouple and found a −60 °C offset, which may have caused the lower graphitization yields (detected from the large isotopic fractionation on several reference materials targets). At a temperature of 520 °C, the isotopic fractionation in the graphitization reaction was systematically lower (−5‰ in average) and the overall scattering was reduced. As long as isotopic fractionation corrections are made using the online stable isotopes ratios provided by the AMS system, the accuracy of the {sup 14}C results should be maintained.

  10. Radiocarbon-based source apportionment of black carbon (BC) in PM 10 aerosols from residential area of suburban Tokyo

    Science.gov (United States)

    Uchida, Masao; Kumata, Hidetoshi; Koike, Yasuyo; Tsuzuki, Mikio; Uchida, Tatsuya; Fujiwara, Kitao; Shibata, Yasuyuki

    2010-04-01

    The AMS technique was applied to analyse black carbon (BC), total organic carbon (TOC), and previously reported polycyclic aromatic hydrocarbons (PAHs) in PM 10 aerosols from a residential area, suburban Tokyo, to determine natural abundance of radiocarbon ( 14C), an ideal tracer to distinguish fossil fuel ( 14C-free) from modern biomass combustion sources of pyrolytic products. The 14C concentrations in BC, isolated using the CTO-375 method, were 42% and 30% pMC (in terms of percent Modern Carbon: pMC) in summer and winter, respectively. The 14C concentrations in BC were also compared with those of compound-class specific 14C content of PAHs previously reported for the same samples: they were 45% and 33% pMC in summer and winter, respectively. The 14C signals of BC were identical to those of high molecular weight (MW ⩾ 226, 5-6 rings) PAHs. The resemblance between 14C signals of BC and PAHs can be referred as a 'certificate' for the validity of the BC isolation method employed in this study. Also, it suggests that 14C-BC approach can be a surrogate for PAHs specific 14C analyses to monitor seasonal source variation of combustion-derived pyrolytic products. On the other hand, 14C contents of total organic carbon in 2004 were 61% and 42% pMC in summer and winter, respectively. This is likely attributed to higher contribution of plant activity in summer.

  11. Radiometric Dating Does Work!

    Science.gov (United States)

    Dalrymple, G. Brent

    2000-01-01

    Discusses the accuracy of dating methods and creationist arguments that radiometric dating does not work. Explains the Manson meteorite impact and the Pierre shale, the ages of meteorites, the K-T tektites, and dating the Mount Vesuvius eruption. (Author/YDS)

  12. Radiocarbon Based Ages and Growth Rates: Hawaiian Deep Sea Corals

    Energy Technology Data Exchange (ETDEWEB)

    Roark, E B; Guilderson, T P; Dunbar, R B; Ingram, B L

    2006-01-13

    The radial growth rates and ages of three different groups of Hawaiian deep-sea 'corals' were determined using radiocarbon measurements. Specimens of Corallium secundum, Gerardia sp., and Leiopathes glaberrima, were collected from 450 {+-} 40 m at the Makapuu deep-sea coral bed using a submersible (PISCES V). Specimens of Antipathes dichotoma were collected at 50 m off Lahaina, Maui. The primary source of carbon to the calcitic C. secundum skeleton is in situ dissolved inorganic carbon (DIC). Using bomb {sup 14}C time markers we calculate radial growth rates of {approx} 170 {micro}m y{sup -1} and ages of 68-75 years on specimens as tall as 28 cm of C. secundum. Gerardia sp., A. dichotoma, and L. glaberrima have proteinaceous skeletons and labile particulate organic carbon (POC) is their primary source of architectural carbon. Using {sup 14}C we calculate a radial growth rate of 15 {micro}m y{sup -1} and an age of 807 {+-} 30 years for a live collected Gerardia sp., showing that these organisms are extremely long lived. Inner and outer {sup 14}C measurements on four sub-fossil Gerardia spp. samples produce similar growth rate estimates (range 14-45 {micro}m y{sup -1}) and ages (range 450-2742 years) as observed for the live collected sample. Similarly, with a growth rate of < 10 {micro}m y{sup -1} and an age of {approx}2377 years, L. glaberrima at the Makapuu coral bed, is also extremely long lived. In contrast, the shallow-collected A. dichotoma samples yield growth rates ranging from 130 to 1,140 {micro}m y{sup -1}. These results show that Hawaiian deep-sea corals grow more slowly and are older than previously thought.

  13. Holocene glacier fluctuations and climate changes in the southeastern part of the Russian Altai (South Siberia) based on a radiocarbon chronology

    Science.gov (United States)

    Agatova, A. R.; Nazarov, A. N.; Nepop, R. K.; Rodnight, H.

    2012-06-01

    This study investigates glacier dynamic and climatic variations in the southeastern part of the Russian Altai (SE Altai) during the last 7000 years. Recent glacier retreats and ice melting in moraines has led to exhumation of organic material allowing the possibility of radiocarbon dating. We report here 57 new radiocarbon dates from wood remains buried by moraines and from proglacial forefields, from peat layers and lacustrine sediments that cover moraines, from dead trees at the upper tree limit, and from rock glaciers on trough slopes from six glacial valleys in the North Chuya Range, SE Altai. Such a numerous dataset for the vast but unified in neotectonic and climatic conditions area is presented for the first time the history of research in the Altai. Together with 62 previously published radiocarbon ages, mainly of fossil soils and peat layers in the foot of the ranges in SE Altai, they form the basis for understanding the relative magnitudes and timing of the most important glacial and climatic events of SE Altai. New data refute the traditional concept of the Russian Altai Holocene glaciations as a consecutive retreat of the late Würm glaciers and argue their complete degradation at the head of trough valleys at least 7000 cal. years BP. Moraine complexes of three Holocene glacial stages are morphologically expressed in trough valleys of the North Chuya range. They correlate with three identified periods of glacial advances: from 4900 to 4200 cal. years BP (Akkem stage), from 2300 to 1700 cal. years BP (Historical stage) and in the 13th-19th centuries (Little Ice Age (LIA) or Aktru stage). The coincident extremes of lowering temperature and increasing precipitation during the Akkem stage led to abrupt glacier advances and forming of the most remote moraine complexes downstream in the valleys. Following glacier advances had distinctly smaller magnitudes. In addition to the radiocarbon data, the time limits of the Historical stage were defined more

  14. Introduction to the AMS Experiment

    CERN Document Server

    CERN. Geneva

    2015-01-01

    Following the pioneering experiments (ATIC, BESS, CREAM, HEAT, PAMELA, …), using a magnetic spectrometer (AMS) on ISS is a unique way to provide precision long term measurements of primordial high energy charged cosmic rays. AMS was installed on the Station in May 2011. Up to now, 60 billion events have been collected. 40 billion events have been partially analysed. AMS is scheduled to be on the Station until at least 2024. By then AMS will have collected close to 200 billion events. The detector properties and the analysis methods will be introduced.

  15. Intracavity optogalvanic spectroscopy: Is there any evidence of a radiocarbon signal?

    Energy Technology Data Exchange (ETDEWEB)

    Persson, Anders; Salehpour, Mehran

    2015-10-15

    In 2008, the first report of an ultrasensitive method for ro-vibrational spectrometry of radiocarbon dioxide was published. The method, called intracavity optogalvanic spectroscopy (ICOGS), claimed a sensitivity and limit-of-detection comparable to accelerator mass spectroscopy. ICOGS was claimed to utilize the isotope-dependent ro-vibrational absorption lines of carbon dioxide in the infrared spectrum. In order to facilitate unambiguous detection of radiocarbon, the sample was placed inside the cavity of a radiocarbon dioxide laser. This intracavity approach was claimed to increase the sensitivity by seven orders of magnitude compared with traditional optogalvanic methods. However, despite the methodical and thorough efforts of several research groups worldwide, these claims have not been possible to reproduce. Instead, we have previously reported serious deviations from the original results, where we found that ICOGS suffers from considerable problems with the stability and reproducibility of the optogalvanic signal, and that misinterpretations of these uncertainties likely are the explanation for the claimed sensitivity in the first reports. Having identified the stability and reproducibility of the detection as major concerns, we decided to improve the setup by with state-of-the-art plasma source technology. Deploying a custom-made stripline split-ring resonator optogalvanic detector, we have now investigated the applicability of ICOGS to radiocarbon detection even further. Measurements have been made with a wide range of parameters including different gas mixtures at various pressures and wavelengths. We have also conducted measurements with gas flowing through the sample cell to investigate the effect of plasma induced decomposition of the sample. Still, we have seen no indications of a significant radiocarbon signal in a concentration range between 0.29 Modern and 9.7 Modern, i.e., the range of interest to the radiocarbon community. Hence, our conclusions

  16. Intracavity optogalvanic spectroscopy: Is there any evidence of a radiocarbon signal?

    Science.gov (United States)

    Persson, Anders; Salehpour, Mehran

    2015-10-01

    In 2008, the first report of an ultrasensitive method for ro-vibrational spectrometry of radiocarbon dioxide was published. The method, called intracavity optogalvanic spectroscopy (ICOGS), claimed a sensitivity and limit-of-detection comparable to accelerator mass spectroscopy. ICOGS was claimed to utilize the isotope-dependent ro-vibrational absorption lines of carbon dioxide in the infrared spectrum. In order to facilitate unambiguous detection of radiocarbon, the sample was placed inside the cavity of a radiocarbon dioxide laser. This intracavity approach was claimed to increase the sensitivity by seven orders of magnitude compared with traditional optogalvanic methods. However, despite the methodical and thorough efforts of several research groups worldwide, these claims have not been possible to reproduce. Instead, we have previously reported serious deviations from the original results, where we found that ICOGS suffers from considerable problems with the stability and reproducibility of the optogalvanic signal, and that misinterpretations of these uncertainties likely are the explanation for the claimed sensitivity in the first reports. Having identified the stability and reproducibility of the detection as major concerns, we decided to improve the setup by with state-of-the-art plasma source technology. Deploying a custom-made stripline split-ring resonator optogalvanic detector, we have now investigated the applicability of ICOGS to radiocarbon detection even further. Measurements have been made with a wide range of parameters including different gas mixtures at various pressures and wavelengths. We have also conducted measurements with gas flowing through the sample cell to investigate the effect of plasma induced decomposition of the sample. Still, we have seen no indications of a significant radiocarbon signal in a concentration range between 0.29 Modern and 9.7 Modern, i.e., the range of interest to the radiocarbon community. Hence, our conclusions

  17. Constraint on radiocarbon age correction in Lake Biwa environment from the middle to late Holocene

    Energy Technology Data Exchange (ETDEWEB)

    Miyata, Y., E-mail: miyata@nendai.nagoya-u.ac.jp [Center for Chronological Research, Nagoya University, Nagoya 464-8602 (Japan); National Museum of Japanese History, Sakura 285-8502 (Japan); Minami, M. [Center for Chronological Research, Nagoya University, Nagoya 464-8602 (Japan); Onbe, S. [National Museum of Japanese History, Sakura 285-8502 (Japan); Archaeological Heritage Management Office, Tokushima University, Tokushima 770-8503 (Japan); Sakamoto, M. [National Museum of Japanese History, Sakura 285-8502 (Japan); Nakamura, T. [Center for Chronological Research, Nagoya University, Nagoya 464-8602 (Japan); Imamura, M. [National Museum of Japanese History, Sakura 285-8502 (Japan)

    2013-01-15

    Using data from previous studies and newly collected data, we compared the measured radiocarbon ages of molluscan shells, common reed (Phragmites australis) and pine needles (Pinus thunbergii) collected in 1966, 1970, 1990 and 2008 at Lake Biwa in Japan, and of archaeological samples, to examine radiocarbon reservoir effects at Lake Biwa. We also tested for differences in the radiocarbon reservoir effect between species and locations in the lake. The effects of nuclear bomb tests conducted in the 1950s and 1960s are clear, the offset between atmospheric {sup 14}C and the Lake Biwa freshwater {sup 14}C is larger for this period because the atmospheric {sup 14}C is so high. The semiclosed Lake Biwa system is in dynamic equilibrium with the atmosphere, resulting in the {sup 14}C content of the water following the changes in atmospheric {sup 14}C caused by nuclear testing. The shells collected after 1990 had radiocarbon ages that were 330-450 {sup 14}C years older than those of the coeval atmosphere. The apparent differences in radiocarbon age (about 300 {sup 14}C years) between shell fossils and wood samples excavated from the same layer of the submerged Awazu shell midden at Lake Biwa suggest that the radiocarbon reservoir effect also existed in the middle Holocene (the Middle Jomon period, about 5000 years ago). Because the present-day average residence time of Lake Biwa water is 3-6 years, its direct influence on the radiocarbon reservoir effect is small, which suggests that old carbon has been supplied into Lake Biwa.

  18. Radiocarbon ages of Holocene Pelado, Guespalapa, and Chichinautzin scoria cones, south of Mexico City: implications for archaeology and future hazards

    Science.gov (United States)

    Siebe, Claus; Rodríguez-Lara, Virgilio; Schaaf, Peter; Abrams, Michael

    Pelado, Guespalapa, and Chichinautzin monogenetic scoria cones located within the Sierra del Chichinautzin Volcanic Field (SCVF) at the southern margin of Mexico City were dated by the radiocarbon method at 10,000, 2,800-4,700, and 1,835 years b.p., respectively. Most previous research in this area was concentrated on Xitle scoria cone, whose lavas destroyed and buried the pre-Hispanic town of Cuicuilco around 1,665+/-35 years b.p. The new dates indicate that the recurrence interval for monogenetic eruptions in the central part of the SCVF and close to the vicinity of Mexico City is <2,500 years. If the entire SCVF is considered, the recurrence interval is <1,700 years. Based on fieldwork and Landsat imagery interpretation a geologic map was produced, morphometric parameters characterizing the cones and lava flows determined, and the areal extent and volumes of erupted products estimated. The longest lava flow was produced by Guespalapa and reached 24 km from its source; total areas covered by lava flows from each eruption range between 54 (Chichinautzin) and 80 km2 (Pelado); and total erupted volumes range between 1 and 2 km3/cone. An average eruption rate for the entire SCVF was estimated at 0.6 km3/1,000 years. These findings are of importance for archaeological as well as volcanic hazards studies in this heavily populated region.

  19. Radiocarbon dating of seized ivory confirms rapid decline in African elephant populations and provides insight into illegal trade

    Science.gov (United States)

    Cerling, Thure E.; Barnette, Janet E.; Chesson, Lesley A.; Douglas-Hamilton, Iain; Gobush, Kathleen S.; Uno, Kevin T.; Wasser, Samuel K.; Xu, Xiaomei

    2016-11-01

    Carbon-14 measurements on 231 elephant ivory specimens from 14 large ivory seizures (≥0.5 ton) made between 2002 and 2014 show that most ivory (ca. 90%) was derived from animals that had died less than 3 y before ivory was confiscated. This indicates that the assumption of recent elephant death for mortality estimates of African elephants is correct: Very little “old” ivory is included in large ivory shipments from Africa. We found only one specimen of the 231 analyzed to have a lag time longer than 6 y. Patterns of trade differ by regions: East African ivory, based on genetic assignments of geographic origin, has a much higher fraction of “rapid” transit than ivory originating in the Tridom region of Cameroon-Gabon-Congo. Carbon-14 is an important tool in understanding patterns of movement of illegal wildlife products.

  20. The AD 1300-1700 eruptive periods at Tungurahua volcano, Ecuador, revealed by historical narratives, stratigraphy and radiocarbon dating

    NARCIS (Netherlands)

    Le Pennec, J. -L.; Jaya, D.; Samaniego, P.; Ramon, P.; Yanez, S. Moreno; Egred, J.; van der Plicht, J.

    2008-01-01

    Tungurahua is a frequently active and hazardous volcano of the Ecuadorian Andes that has experienced pyroclastic flow-forming eruption in 1773, 1886, 1916-18 and 2006-08. Earlier eruptions in Late Pre-Hispanic and Early Colonial times have remained poorly known and are debated in the literature. To

  1. Towards a complete {sup 14}C AMS facility at the Universidade Federal Fluminense (Niteroi, Brazil): Sample preparation laboratory tests

    Energy Technology Data Exchange (ETDEWEB)

    Anjos, R.M., E-mail: meigikos@if.uff.br [Instituto de Fisica, Universidade Federal Fluminense, Av. Gal Milton Tavares de Souza, s/no, Gragoata, 24210-346 Niteroi, RJ (Brazil); Macario, K.D.; Gomes, P.R.S.; Linares, R.; Queiroz, E.; Carvalho, C. [Instituto de Fisica, Universidade Federal Fluminense, Av. Gal Milton Tavares de Souza, s/no, Gragoata, 24210-346 Niteroi, RJ (Brazil)

    2013-01-15

    Highlights: Black-Right-Pointing-Pointer We report a new AMS facility at the Physics Institute of UFF in Brazil. Black-Right-Pointing-Pointer A NEC 250 kV single stage accelerator mass spectrometer (SSAMS). Black-Right-Pointing-Pointer The first lab to perform the {sup 14}C-AMS technique not only in Brazil but in Latin America. Black-Right-Pointing-Pointer We report preliminary results and plans for the future. - Abstract: The new radiocarbon sample preparation laboratory at the Physics Institute of the Universidade Federal Fluminense (UFF) in Brazil is discussed and early trials with reference materials are presented, leading up to the installation of a single-stage AMS system in early 2012.

  2. Measuring Carbon-based Contaminant Mineralization Using Combined CO2 Flux and Radiocarbon Analyses

    Science.gov (United States)

    Boyd, Thomas J.; Montgomery, Michael T.; Cuenca, Richard H.; Hagimoto, Yutaka

    2016-01-01

    A method is described which uses the absence of radiocarbon in industrial chemicals and fuels made from petroleum feedstocks which frequently contaminate the environment. This radiocarbon signal — or rather the absence of signal — is evenly distributed throughout a contaminant source pool (unlike an added tracer) and is not impacted by biological, chemical or physical processes (e.g., the 14C radioactive decay rate is immutable). If the fossil-derived contaminant is fully degraded to CO2, a harmless end-product, that CO2 will contain no radiocarbon. CO2 derived from natural organic matter (NOM) degradation will reflect the NOM radiocarbon content (usually <30,000 years old). Given a known radiocarbon content for NOM (a site background), a two end-member mixing model can be used to determine the CO2 derived from a fossil source in a given soil gas or groundwater sample. Coupling the percent CO2 derived from the contaminant with the CO2 respiration rate provides an estimate for the total amount of contaminant degraded per unit time. Finally, determining a zone of influence (ZOI) representing the volume from which site CO2 is collected allows determining the contaminant degradation per unit time and volume. Along with estimates for total contaminant mass, this can ultimately be used to calculate time-to-remediate or otherwise used by site managers for decision-making. PMID:27805601

  3. Single-grain and multigrain luminescence dating of on-ice and lake-bottom deposits at Lake Hoare, Taylor Valley, Antarctica

    DEFF Research Database (Denmark)

    Berger, G.W.; Doran, P.T.; Thomsen, Kristina Jørkov

    2010-01-01

    The large radiocarbon (14C) reservoir effect in Antarctica varies regionally and with settings. Luminescence sediment dating has potential as an alternate geochronometer. Extending our earlier tests of the effectiveness of resetting of photon-stimulated-luminescence (PSL) that employed only multi...

  4. Location of radiocarbon age dates sampled from vibracores collected by the U.S. Geological Survey within Apalachicola Bay, Florida, 2007 (APP-07_AgeDates, points)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — In 2007, the U.S. Geological Survey collected 24 vibracores within Apalachicola Bay, Florida. The vibracores were collected using a Rossfelder electric percussive...

  5. Análisis radiocarbónico en una tafocenosis de la región pampeana (provincia de Buenos Aires, Argentina: Su vinculación con la Gran Seca de 1827-1832 Radiocarbon Analysis Of A Taphocenosis From The Pampean Region (Buenos Aires Province, Argentina And Its Relationships With The "Great Drought" Of 1827-1832

    Directory of Open Access Journals (Sweden)

    Eduardo P. Tonni

    2008-12-01

    Full Text Available Se estudió una tafocenosis compuesta por gran número de ejemplares de Equus caballus, Bos taurus y Ovis aries, sin selección etaria. Se realizó una datación radiocarbónica sobre el colágeno del hueso de un húmero de Bos taurus; la fecha obtenida resultó "moderna" (entre 1750 y 1950 AD. Sin embargo, la concentración ΔC14 en el espécimen y su comparación con la curva de concentración ΔC14 para América del Sur, permitió inferir una edad de muerte que corresponde al lapso 1817-1828 AD. La fecha inferida refiere el origen de la tafocenosis a la "Gran Seca", uno de los eventos de sequía más importantes de la región pampeana, sobre el que se tiene registro histórico. Es éste el primer registro paleontológico de un evento de mortandad masiva de ganado relacionado con las frecuentes sequías verificada en la región pampeana durante los siglos XVIII y XIX.A taphocenosis composed of a great number of specimens of Equus caballus, Bos taurus and Ovis aries, without age selection, was analyzed. A radiocarbon date from the bone collagen of a humerus of Bos taurus was obtained; the date is "modern" (between AD 1750 and 1950. However, the 14C concentration of the specimen and its comparison with the South America concentration curve enabled the date to be narrowed down. The inferred date corresponds to the period AD 1817-1828, and suggests that the origin of the taphocenosis is related to the "Gran Seca" ("Great Drought", one of the most important drought events in the Pampeana Region for which there are historical records. This is the first paleontological record of an event of mass death of livestock related to the frequent droughts that affected the Pampean Region during the seventeenth and eighteenth centuries.

  6. Optical dating using feldspar from Quaternary alluvial and colluvial sediments from SE Brazilian Plateau, Brazil

    Energy Technology Data Exchange (ETDEWEB)

    Tatumi, Sonia H. E-mail: tatumi@fatecsp.br; Peixoto, Maria Naise O.; Moura, Josilda R.S.; Mello, Claudio L.; Carmo, Isabela O.; Kowata, Emilia A.; Yee, Marcio; Brito, Silvio Luiz M.; Gozzi, Giuiliano; Kassab, Luciana R.P

    2003-05-01

    Opticallly stimulated luminescence (OSL) dating has been applied to a wide variety of materials such as loess, sand dunes, colluvium, alluvium, volcanic products, etc., helping geologic geomorphologic studies. OSL dating results using feldspar crystals extracted from alluvial and colluvial deposits of SE Brazilian Plateau will be presented in this work. The methodology used is based on the regeneration method, with multiple aliquot protocol. A total of 23 sample ages were obtained spanning 6.5-97.2 kyr. Results of radioactive contents and comparison with radiocarbon ages will be discussed.

  7. Black Carbon in Marine Dissolved Organic Carbon: Abundance and Radiocarbon Measurements in the Global Ocean

    Science.gov (United States)

    Coppola, A. I.; Walker, B. D.; Druffel, E. R. M.

    2014-12-01

    Compound specific radiocarbon analysis is a powerful tool for understanding the cycling of individual components, such as black carbon (BC) produced from biomass burning and fossil fuel combustion, within bulk pools, like the marine dissolved organic carbon pool. Here, we use a solid phase extraction method and a wide range of solvent polarities to concentrate dissolved organic carbon from seawater. Then we isolate BC in sufficient quantities for radiocarbon analysis. We report the radiocarbon age of BC, concentrations and its relative structure, from coastal and open ocean surface samples. We will discuss our progress towards measuring these quantities in dissolved organic carbon collected from the Pacific and Atlantic oceans to understand the fate, transformation and cycling of BC in the world ocean. These measurements are paired with bulk DOC Δ14C profiles, providing insight into the role of BC as a missing sink in the ultra-refractory DOC pool.

  8. An Overview of the Use of Absolute Dating Techniques in Ancient Construction Materials

    Directory of Open Access Journals (Sweden)

    Jorge Sanjurjo-Sánchez

    2016-04-01

    Full Text Available The reconstruction of the chronology of historical buildings is a tricky issue, as usually there are not historical documents that allow the assessment of construction phases, and some materials are hardly reliable for the use of dating techniques (e.g., stone. However, in the last two decades, important advances on the use of absolute dating methods on building materials have increased the possibilities of reconstructing building chronologies, although some advances are still scarcely known among archaeologists and architects. Recent studies performed on several kinds of mortars, fired bricks, mud-bricks, and even stone surfaces have shown that it is possible to date them. Both radiocarbon and luminescence dating have been the most frequently used techniques but others such as archaeomagnetism can also be used in some cases. This paper intends to give an overview of the recent achievements on the use of absolute dating techniques for building materials.

  9. Holocene age of the Yuha burial: Direct radiocarbon determinations by accelerator mass spectrometry

    Science.gov (United States)

    Stafford, Thomas W.; Jull, A.J.T.; Zabel, T.H.; Donahue, D.J.; Duhamel, R.C.; Brendel, K.; Haynes, C.V.; Bischoff, J.L.; Payen, L.A.; Taylor, R.E.

    1984-01-01

    The view that human populations may not have arrived in the Western Hemisphere before about 12,000 radiocarbon yr BP1,2 has been challenged by claims of much greater antiquity for a small number of archaeological sites and human skeleton samples. One such site is the Homo sapiens sapiens cairn burial excavated in 1971 from the Yuha desert, Imperial County, California3-5. Radiocarbon analysis of caliche coating one of the bones of the skeleton yielded a radiocarbon age of 21,500??1,000 yr BP4, while radiocarbon and uranium series analyses of caliche coating a cairn boulder yielded ages of 22,125??400 and 19,000??3,000 yr BP, respectively5. The late Pleistocene age assignment to the Yuha burial has been challenged by comparing the cultural context of the burial with other cairn burials in the same region6, on the basis of the site's geomorphological context and from radiocarbon analyses of soil caliches. 7,8 In rebuttal, arguments in defence of the original age assignment have been presented9,10 as well as an amino acid racemization analysis on the Yuha skeleton indicating an age of 23,600??2,600 yr BP11. The tandem accelerator mass spectrometer at the University of Arizona has now been used to measure the ratio of 14C/13C in several organic and inorganic fractions of post-cranial bone from the Yuha H. sapiens sapiens skeleton. Isotope ratios from six chemical fractions all yielded radiocarbon ages for the skeleton of less than 4,000 yr BP. These results indicate that the Yuha skeleton is of Holocene age, in agreement with the cultural context of the burial, and in disagreement with the previously assigned Pleistocene age of 19,000-23,000 yr. ?? 1984 Nature Publishing Group.

  10. Calculation of the Solar Activity Effect on the Production Rate of Cosmogenic Radiocarbon in Polar Ice

    CERN Document Server

    Nesterenok, A V

    2012-01-01

    The propagation of cosmic rays in the Earth's atmosphere is simulated. Calculations of the omnidirectional differential flux of neutrons for different solar activity levels are presented. The solar activity effect on the production rate of cosmogenic radiocarbon by the nuclear-interacting and muon components of cosmic rays in polar ice is studied. It has been obtained that the $^{14}C$ production rate in ice by the cosmic ray nuclear-interacting component is lower or higher than the average value by 30% during periods of solar activity maxima or minima, respectively. Calculations of the altitudinal dependence of the radiocarbon production rate in ice by the cosmic ray components are illustrated.

  11. Simultaneous measurement of tritium and radiocarbon by ultra-low-background proportional counting.

    Science.gov (United States)

    Mace, Emily; Aalseth, Craig; Alexander, Tom; Back, Henning; Day, Anthony; Hoppe, Eric; Keillor, Martin; Moran, Jim; Overman, Cory; Panisko, Mark; Seifert, Allen

    2016-12-21

    Use of ultra-low-background capabilities at Pacific Northwest National Laboratory provide enhanced sensitivity for measurement of low-activity sources of tritium and radiocarbon using proportional counters. Tritium levels are nearly back to pre-nuclear test backgrounds (~2-8 TU in rainwater), which can complicate their dual measurement with radiocarbon due to overlap in the beta decay spectra. We present results of single-isotope proportional counter measurements used to analyze a dual-isotope methane sample synthesized from ~120mg of H2O and present sensitivity results.

  12. 10Be inventories in Alpine soils and their potentiality for dating land surfaces

    Science.gov (United States)

    Egli, Markus; Brandová, Dagmar; Böhlert, Ralph; Favilli, Filippo; Kubik, Peter W.

    2010-05-01

    To exploit natural archives and geomorphic objects it is necessary to date them first. Landscape evolution of Alpine areas is often strongly related to the activities of glaciers in the Pleistocene and Holocene. At sites where no organic matter for radiocarbon dating exists and where suitable boulders for surface exposure dating (using in situ produced cosmogenic nuclides) are absent, dating of soils could give information about the timing of landscape evolution. We explored the applicability of soil dating using the inventory of meteoric Be-10 in Alpine soils. For this purpose, a set of 6 soil profiles in the Swiss and Italian Alps was investigated. The surface at these sites had already been dated (using the radiocarbon technique or surface exposure dating using in situ produced Be-10). Consequently, a direct comparison of the ages of the soils using meteoric Be-10 and other dating techniques was made possible. The estimation of Be-10 deposition rates is subject to severe limitations and strongly influences the obtained results. We tested three scenarios using a) the meteoric Be-10 deposition rates as a function of the annual precipitation rate, b) a constant Be-10 input for the Central Alps and c) as b) but assuming a pre-exposure of the parent material. The obtained ages that are based on the Be-10 inventory in soils and on scenario a) for the Be-10 input agreed reasonably well with the expected age (obtained from surface exposure or radiocarbon dating). The ages obtained from soils using scenario b) produced mostly ages that were too old whereas the approach using scenario c) seemed to yield better results than scenario b). Erosion calculations can, in theory, be performed using the Be-10 inventory and Be-10 deposition rates. An erosion estimation was possible using scenario a) and c), but not using b). The estimated erosion rates are in a reasonable range. The dating of soils using Be-10 has several potential error sources. Analytical errors as well as errors

  13. A non-destructive method for dating human remains

    Science.gov (United States)

    Lail, Warren K.; Sammeth, David; Mahan, Shannon; Nevins, Jason

    2013-01-01

    The skeletal remains of several Native Americans were recovered in an eroded state from a creek bank in northeastern New Mexico. Subsequently stored in a nearby museum, the remains became lost for almost 36 years. In a recent effort to repatriate the remains, it was necessary to fit them into a cultural chronology in order to determine the appropriate tribe(s) for consultation pursuant to the Native American Grave Protection and Repatriation Act (NAGPRA). Because the remains were found in an eroded context with no artifacts or funerary objects, their age was unknown. Having been asked to avoid destructive dating methods such as radiocarbon dating, the authors used Optically Stimulated Luminescence (OSL) to date the sediments embedded in the cranium. The OSL analyses yielded reliable dates between A.D. 1415 and A.D. 1495. Accordingly, we conclude that the remains were interred somewhat earlier than A.D. 1415, but no later than A.D. 1495. We believe the remains are from individuals ancestral to the Ute Mouache Band, which is now being contacted for repatriation efforts. Not only do our methods contribute to the immediate repatriation efforts, they provide archaeologists with a versatile, non-destructive, numerical dating method that can be used in many burial contexts.

  14. Pyrolysis-combustion 14C dating of soil organic matter

    Science.gov (United States)

    Wang, Hong; Hackley, Keith C.; Panno, Samuel V.; Coleman, Dennis D.; Liu, Jack Chao-li; Brown, Johnie

    2003-11-01

    Radiocarbon ( 14C) dating of total soil organic matter (SOM) often yields results inconsistent with the stratigraphic sequence. The onerous chemical extractions for SOM fractions do not always produce satisfactory 14C dates. In an effort to develop an alternative method, the pyrolysis-combustion technique was investigated to partition SOM into pyrolysis volatile (Py-V) and pyrolysis residue (Py-R) fractions. The Py-V fractions obtained from a thick glacigenic loess succession in Illinois yielded 14C dates much younger but more reasonable than the counterpart Py-R fractions for the soil residence time. Carbon isotopic composition (δ 13C) was heavier in the Py-V fractions, suggesting a greater abundance of carbohydrate- and protein-related constituents, and δ 13C was lighter in the Py-R fractions, suggesting more lignin- and lipid-related constituents. The combination of 14C dates and δ 13C values indicates that the Py-V fractions are less biodegradation resistant and the Py-R fractions are more biodegradation resistant. The pyrolysis-combustion method provides a less cumbersome approach for 14C dating of SOM fractions. With further study, this method may become a useful tool for analyzing unlithified terrestrial sediments when macrofossils are absent.

  15. Date with Death

    Institute of Scientific and Technical Information of China (English)

    郑慧敏

    2016-01-01

    Have you ever heard about a popular movie called date with an angel? It must be sweet and lovely. But have you ever imagine about dating with death? What is your feeling when you have a chance to talk with death? Excited or afraid? I believe that many people definitely do not think about this question and neither do I.

  16. Radiometric Dating in Geology.

    Science.gov (United States)

    Pankhurst, R. J.

    1980-01-01

    Described are several aspects and methods of quantitatively measuring geologic time using a constant-rate natural process of radioactive decay. Topics include half lives and decay constants, radiogenic growth, potassium-argon dating, rubidium-strontium dating, and the role of geochronology in support of geological exploration. (DS)

  17. Dating of cremated bones

    NARCIS (Netherlands)

    Lanting, JN; Aerts-Bijma, AT; van der Plicht, J; Boaretto, E.; Carmi, I.

    2001-01-01

    When dating unburnt bone, bone collagen, the organic fraction of the bone, is used. Collagen does not survive the heat of the cremation pyre, so dating of cremated bone has been considered impossible. Structural carbonate in the mineral fraction of the bone, however, survives the cremation process.

  18. Second Quaternary dating workshop

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1999-11-01

    The second Quaternary dating methods workshop was held at Lucas Heights and sponsored by ANSTO and AINSE. Topics covered include, isotope and thermoluminescence dating, usage of accelerator and thermal ionisation mass spectrometry in environmental studies emphasizing on the methodologies used and sample preparation

  19. Pests of stored dates

    Science.gov (United States)

    Dates are a major food crop across a large band of Africa and Eurasia, and to a lesser extent elsewhere. In most of its growing range, dates are threatened with infestation in the field by a complex of pests including nitidulid beetles and pyralid moths of the Subfamily Phycitinae. They are further ...

  20. Banach格上正则AM-紧算子的AM-空间%AM-space and AL-space of Positive AM-compact Operators on Banach Lattices

    Institute of Scientific and Technical Information of China (English)

    程娜; 李曦

    2013-01-01

      给出Banach格上所有从E到F的正则AM-紧算子空间在・ AM范数下是AL-空间,当且仅当E是AM-空间,且F是AL-空间;正则AM-紧算子空间在・ AM范数下是AM-空间,当且仅当E是AL-空间,F是AM-空间。%It is shown that the space generated by all positive AM-compact operators from E into F, is an AL-space under the・ AM -norm if and only if E is an AM-space and F is an AL-space;the space of all positive AM-compact operators from E into F is an AM-space under ・ AM -norm if and only if E is an AL-space and F is an AM-space.

  1. Optically stimulated luminescence dating of cave deposits at the Xiaogushan prehistoric site, northeastern China.

    Science.gov (United States)

    Zhang, Jia-Fu; Huang, Wei-Wen; Yuan, Bao-Yin; Fu, Ren-Yi; Zhou, Li-Ping

    2010-11-01

    The Xiaogushan cave site is one of the most important prehistoric sites in North China. The stone and bone artifacts found in the cave are similar to European contemporaneous artifacts. Cave deposits consist of five layers that have been dated from 46,353 ± 1179 to 4229 ± 135 cal. yr BP, using radiocarbon dating techniques on charcoal and bone samples collected from Layers 2-5. In this paper, optically stimulated luminescence (OSL) techniques were applied to date six samples taken from Layers 1-3. The luminescence properties of the fine-grained and coarse-grained quartz extracts indicate that the materials are suitable for OSL dating using a single-aliquot regeneration-dose (SAR) protocol. The OSL ages obtained are broadly consistent with the stratigraphy and the associated calibrated radiocarbon ages. The dating results show that the cave was first occupied by humans about 70 ka. The human occupation of the cave may be related to climate change. An occupation hiatus is inferred to between ∼ 17 to ∼ 10 ka. The stone and bone artifacts found in Layers 2 and 3 may indicate the Middle to Upper Paleolithic transitions in the region.

  2. New frontiers-accelerator mass spectrometry (AMS): Recommendation for best practices and harmonization from Global Bioanalysis Consortium Harmonization Team.

    Science.gov (United States)

    Young, Graeme C; Seymour, Mark; Dueker, Stephen R; Timmerman, Philip; Arjomand, Ali; Nozawa, Kohei

    2014-03-01

    The technique of accelerator mass spectrometry (AMS) is applicable to the analysis of a wide range of trace elemental isotopes. However, in the context of the pharmaceutical industry, it is invariably used to measure radiocarbon ((14)C). There are two broad modes of application: analysis of total (14)C sometimes termed "direct AMS" and analysis of specific (14)C-labelled analytes in a variety of matrices following some method of isolation. It is the latter application which is within the remit of the GBC team, and the team has made efforts to propose harmonized recommendations for the validation of AMS when used in a regulatory bioanalytical mode, i.e. the quantification of specific analyte(s) using liquid chromatography with off-line detection by AMS now known as "LC + AMS". The GBC team has reached a position where they have agreed to many aspects, but also differ on some aspects of what constitutes a bioanalytical assay validation in support of clinical studies using this technology. The detail of most of this will be covered under separate publication(s), but for the purposes of this paper, we have outlined the points of consensus. The purpose of this article is not to provide a roadmap for validation of LC + AMS assays, but to highlight agreements amongst the industry representative experts and the practitioners, as well as identifying specific areas essential for establishing assay quality but where additional discussion is required to reach agreement.

  3. Tritium AMS for biomedical applications

    Energy Technology Data Exchange (ETDEWEB)

    Roberts, M.L.; Velsko, C.; Turteltaub, K.W.

    1993-08-01

    We are developing {sup 3}H-AMS to measure {sup 3}H activity of mg-sized biological samples. LLNL has already successfully applied {sup 14}C AMS to a variety of problems in the area of biomedical research. Development of {sup 3}H AMS would greatly complement these studies. The ability to perform {sup 3}H AMS measurements at sensitivities equivalent to those obtained for {sup 14}C will allow us to perform experiments using compounds that are not readily available in {sup 14}C-tagged form. A {sup 3}H capability would also allow us to perform unique double-labeling experiments in which we learn the fate, distribution, and metabolism of separate fractions of biological compounds.

  4. AMS-02 fits Dark Matter

    CERN Document Server

    Balázs, Csaba

    2015-01-01

    In this work we perform a comprehensive statistical analysis of the AMS-02 electron, positron fluxes and the antiproton-to-proton ratio in the context of a simplified dark matter model. We include known, standard astrophysical sources and a dark matter component in the cosmic ray injection spectra. To predict the AMS-02 observables we use propagation parameters extracted from observed fluxes of heavier nuclei and the low energy part of the AMS-02 data. We assume that the dark matter particle is a Majorana fermion coupling to third generation fermions via a spin-0 mediator, and annihilating to multiple channels at once. The simultaneous presence of various annihilation channels provides the dark matter model with additional flexibility, and this enables us to simultaneously fit all cosmic ray spectra using a simple particle physics model and coherent astrophysical assumptions. Our results indicate that AMS-02 observations are not only consistent with the dark matter hypothesis within the uncertainties, but add...

  5. 10Be inventories in Alpine soils and their potential for dating land surfaces

    Science.gov (United States)

    Egli, Markus; Brandová, Dagmar; Böhlert, Ralph; Favilli, Filippo; Kubik, Peter W.

    2010-07-01

    To exploit natural sedimentary archives and geomorphic landforms it is necessary to date them first. Landscape evolution of Alpine areas is often strongly related to the activities of glaciers in the Pleistocene and Holocene. At sites where no organic matter for radiocarbon dating exists and where suitable boulders for surface exposure dating (using in situ produced cosmogenic nuclides) are absent, dating of soils could give information about the timing of landscape evolution. This paper explores the applicability of soil dating using the inventory of meteoric 10Be in Alpine soils. For this purpose, a set of 6 soil profiles in the Swiss and Italian Alps was investigated. The surface at these sites had already been dated (using the radiocarbon technique or the surface exposure determination using in situ produced 10Be). Consequently, a direct comparison of the ages of the soils using meteoric 10Be and other dating techniques was made possible. The estimation of 10Be deposition rates is subject to severe limitations and strongly influences the obtained results. We tested three scenarios using a) the meteoric 10Be deposition rates as a function of the annual precipitation rate, b) a constant 10Be input for the Central Alps, and c) as b) but assuming a pre-exposure of the parent material. The obtained ages that are based on the 10Be inventory in soils and on scenario a) for the 10Be input agreed reasonably well with the age using surface exposure or radiocarbon dating. The ages obtained from soils using scenario b) produced ages that were mostly too old whereas the approach using scenario c) seemed to yield better results than scenario b). Erosion calculations can, in theory, be performed using the 10Be inventory and 10Be deposition rates. An erosion estimation was possible using scenario a) and c), but not using b). The calculated erosion rates using these scenarios seemed to be plausible with values in the range of 0-57 mm/ky. The dating of soils using 10Be has

  6. Accelerator mass spectrometry {sup 14}C dating of lime mortars: Methodological aspects and field study applications at CIRCE (Italy)

    Energy Technology Data Exchange (ETDEWEB)

    Marzaioli, Fabio, E-mail: fabio.marzaioli@unina2.it [CIRCE, INNOVA and Seconda Universita degli Studi di Napoli, Dipartimento di Scienze Ambientali, Caserta (Italy); Nonni, Sara, E-mail: sara.nonni@uniroma1.it [Dipartimento di Scienze della Terra, ' Sapienza' Universita di Roma (Italy); Passariello, Isabella, E-mail: isabella.passariello@unina2.it [CIRCE, INNOVA and Seconda Universita degli Studi di Napoli, Dipartimento di Scienze Ambientali, Caserta (Italy); Capano, Manuela, E-mail: manuela.capano@unina2.it [CIRCE, INNOVA and Dipartimento di Studio delle Componenti Culturali del Territorio, Seconda Universita degli Studi di Napoli, Santa Maria Capua Vetere, Caserta (Italy); Ricci, Paola, E-mail: paola.ricci@unina2.it [CIRCE, INNOVA and Seconda Universita degli Studi di Napoli, Dipartimento di Scienze Ambientali, Caserta (Italy); Lubritto, Carmine, E-mail: carmine.lubritto@unina2.it [CIRCE, INNOVA and Seconda Universita degli Studi di Napoli, Dipartimento di Scienze Ambientali, Caserta (Italy); De Cesare, Nicola, E-mail: nicola.decesare@unina2.it [CIRCE, INNOVA and Seconda Universita degli Studi di Napoli, Dipartimento di Scienze della Vita, Caserta (Italy); Eramo, Giacomo, E-mail: giacomo.eramo@uniba.it [Dipartimento di Scienze della Terra e Geoambientali, Universita degli Studi di Bari ' Aldo Moro' , Bari (Italy); Quiros Castillo, Juan Antonio, E-mail: quiros.castillo@ehu.es [Universidad del Pais Vasco-Euskal Herriko Unibertsitatea, Dipartimento di Geografia, Prehistoria y Arqueologia, Vitoria-Gasteiz (Spain); and others

    2013-01-15

    Centre for Isotopic Research on Cultural and Environmental heritage (CIRCE) has, recently, obtained some promising results in testing the feasibility of mortar radiocarbon dating by means of an ad hoc developed purification procedure (CryoSoniC: Cryobraking, Sonication, Centrifugation) applied to a series of laboratory mortars. Observed results encouraged CryoSoniC accuracy evaluation on genuine mortars sampled from archeological sites of known or independently constrained age (i.e., other {sup 14}C dates on different materials). In this study, some {sup 14}C measurements performed on genuine mortars will be discussed and compared with independently estimated (i.e., radiocarbon/archaeometrical dating) absolute chronologies of two Spanish sites. Observed results confirm the agreement of the CryoSoniC mortar dates with the archaeological expectations for both examined cases. Several authors reported the possibility of obtaining accurate radiocarbon dates of mortar matrices by analyzing lime lumps: binder-related particles of different sizes exclusively composed of calcium carbonate. In this paper, preliminary data for the absolute chronology reconstruction of the Basilica of the cemetery complex of Ponte della Lama (Canosa di Puglia, Italy) based on lime lumps will also be discussed. Dating accuracy will be quantified by comparing {sup 14}C data on mortar lime lumps from a funerary inscription of known age found near the Basilica, in the same study site. For this site, a comparison between absolute chronologies performed by bulk and CryoSoniC purified lime lumps, and charcoal incased in mortars (when found) will also be discussed. Observed results for this site provide evidence of how bulk lime lump dating may introduce systematic overestimations of the analyzed sample while CryoSoniC purification allows accurate dating.

  7. The new AMS control centre

    CERN Multimedia

    Anaïs Schaeffer

    2011-01-01

    Construction work for the future AMS control room began in November 2010 and should be finished this June. The new building, which will have been completed in record time thanks to the professionalism of the project team, will soon be ready to receive the initial data from the AMS experiment.     Luigi Scibile and Michael Poehler, from the GS department, at the AMS control centre construction site.   The Alpha Magnetic Spectrometer (AMS) is due to wing its way towards the International Space Station (ISS) on board the shuttle Discovery in April. Mainly intended for research on antimatter and dark matter, the data collected by AMS will be sent to Houston in the United States and then directly to CERN’s new Building 946. Construction work for the AMS control centre building on the Route Gentner at CERN’s Prévessin site started in November 2010 and must be completed in time to receive the first data from the spectrometer in June. “It normall...

  8. Summary findings of the fourth international radiocarbon intercomparison (FIRI)(1998-2001)

    NARCIS (Netherlands)

    Boaretto, E; Bryant, C; Carmi, [No Value; Cook, G; Gulliksen, S; Harkness, D; Heinemeier, J; McClure, J; McGee, E; Naysmith, P; Possnert, G; Van Der Plicht, H; Van Strydonck, M

    2002-01-01

    Interlaboratory comparisons have been widely used in applied radiocarbon science. These are an important part of ongoing quality assurance (QA) programmes, which are vital to the appropriate interpretation of the evidence provided by the C-14 record in Quaternary applications (including climate chan

  9. Summary findings of the fourth international radiocarbon intercomparison (FIRI) (1998–2001)

    NARCIS (Netherlands)

    Boaretto, Elisabetta; Bryant, Charlotte; Carmi, Israel; Cook, Gordon; Gulliksen, Steinar; Harkness, Doug; Heinemeier, Jan; McClure, John; McGee, Edward; Naysmith, Philip; Possnert, Goran; Scott, Marian; Plicht, Hans van der; Strydonck, Mark van

    2002-01-01

    Interlaboratory comparisons have been widely used in applied radiocarbon science. These are an important part of ongoing quality assurance (QA) programmes, which are vital to the appropriate interpretation of the evidence provided by the 14C record in Quaternary applications (including climate chang

  10. Pollen-based biome reconstructions for Latin America at 0, 6000 and 18 000 radiocarbon years

    NARCIS (Netherlands)

    Marchant, R.; Harrison, S.P.; Hooghiemstra, H.; Cleef, A.M.; Hammen, van der T.; Wille, M.

    2009-01-01

    The biomisation method is used to reconstruct Latin American vegetation at 6000±500 and 18 000±1000 radiocarbon years before present (14C yr BP) from pollen data. Tests using modern pollen data from 381 samples derived from 287 locations broadly reproduce potential natural vegetation. The strong tem

  11. The marine radiocarbon bomb pulse across the temperate North Atlantic: a compilation of Delta

    NARCIS (Netherlands)

    Scourse, J.D.; Wanamaker jr., A.D.; Weidman, C.; Heinemeier, J.; Reimer, P.J.; Butler, P.G.; Witbaard, R.; Richardson, C.A.

    2012-01-01

    Marine radiocarbon bomb-pulse time histories of annually resolved archives from temperate regions have been underexploited. We present here series of Delta C-14 excess from known-age annual increments of the long-lived bivalve mollusk Arctica islandica from 4 sites across the coastal North Atlantic

  12. Radiocarbon, 13C and 15N analysis of fossil bone: Removal of humates with XAD-2 resin

    Science.gov (United States)

    Stafford, Thomas W., Jr.; Brendel, Klaus; Duhamel, Raymond C.

    1988-09-01

    Humic acids are the predominant source of error in the 14C and stable isotope analysis of fossil bone organic matter. XAD-2 resin will quantitatively remove humates and give the highest yields of protein from bones with variable types of preservation. Decalcified bone, gelatin and base-leached residues can vary up to 5%. for δ 13C and by 1%. on δ 15N relative to XAD-treated fractions. Simultaneous analysis of 14C age, δ 13C and δ 15N is recommended because each isotope value can be independently affected by the bone's diagenetic history. Radiocarbon analysis is the most sensitive and δ 15N is least sensitive for detecting exogenous organic matter. The uncertainty of analyses on the best pretreated protein is ±0.5%. for both δ 13C and δ 15N and is larger than previous estimates. The accuracy for all isotope analyses will be better assessed by using individual amino acids instead of total collagenous residues. Inaccurate 14C dates on severely degraded bone are an indication that this class of fossils may be unsuitable for any isotopic analysis.

  13. Role of radiation dating technique - one example

    Energy Technology Data Exchange (ETDEWEB)

    Watanabe, Shigueo [Universidade de Sao Paulo (IF/USP), SP (Brazil). Inst. de Fisica; Etchevarne, Carlos A. [Universidade Federal da Bahia (UFBA), Salvador, BA (Brazil). Fac. de Filosofia e Ciencias Humanas. Dept. Antropologia e Etnologia; Cano, Nilo F.; Munita, C.S. [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2012-07-01

    Full text: The great majority of archaeological or geological dating technique is based on radiation effect. The so called radioactivity method uses radioactive decays of elements. This is the case of the well known radiocarbon or carbon-14 method. Also the method of relating daughter nucleus to decaying nucleus, as in K-40/Ar-40, Th- 230/U-234, etc. Here we will concentrate in the method based on energy deposition in a solid by radiation from the disintegration of U-series and Th-series. {beta}-rays emitted by the decay of K-40 into Ca-40 (80%) and Ar-40 (11%) also contributes. The role of {alpha}, {beta} and {gamma} radiation emitted by radionuclides in the U-238 and Th-232 series and of {beta} rays from the decay of K-40, all of them in the soil irradiate anything in their course. For dating, we can have sediments as well as potteries produced by ancient people and became buried. The important process consists in transferring a fraction of the energy of radiation to the solid, mainly liberating electrons from valence band to conduction band and from there to traps. In many case the energy of the radiation is used to create defects which in turn create energy levels (traps) in the forbidden gap (or energy gap). There are three ways to recover the energy stored in the solid: (1) by emission of light optically stimulated (OSL), (2) by emission of light thermally stimulated (TL), (3) by microwave absorption (EPR or ESR). Using these techniques among several applications, we will present one to find the first settlers in the northeaster region of Brazil. (author)

  14. NAIP 2012 Image Dates

    Data.gov (United States)

    Farm Service Agency, Department of Agriculture — This map is produced by the Aerial Phtography Field Office (APFO) to show the image acquisition dates for the 2012 National Agriculture Imagery Program (NAIP)...

  15. Expiration Dates Matter

    Medline Plus

    Full Text Available ... Blood & Biologics Animal & Veterinary Cosmetics Tobacco Products For Consumers Home For Consumers Consumer Updates Expiration Dates Matter ... Should Know CDER FOIA Electronic Reading Room Related Consumer Updates How to Dispose of Unused Medicines Identifying ...

  16. NAIP 2014 Image Dates

    Data.gov (United States)

    Farm Service Agency, Department of Agriculture — This map is produced by the Aerial Phtography Field Office (APFO) to show the image acquisition dates for the 2014 National Agriculture Imagery Program (NAIP)...

  17. Expiration Dates Matter

    Medline Plus

    Full Text Available ... video, FDA Pharmacist Ilisa Bernstein explains how expiration dates help determine if medicine is safe to use and will work as intended. ... Lock it Up: Medicine Safety in Your Home Giving Medicine to ...

  18. A Blind Date

    Institute of Scientific and Technical Information of China (English)

    周立

    2003-01-01

    英语对话:A: Talking about girls, I still remember my first time to meet my girlfriend. Iwas so clumsy and very nervous.B: That’s the same case with me. I had the jitters at my blind date, too.A: Did you also meet your girlfriend at a blind date?B: Yeah. I was actually very shy of speaking to girls, you know?

  19. The emergence of mesolithic cemeteries in SW Europe: insights from the El Collado (Oliva, Valencia, Spain) radiocarbon record.

    Science.gov (United States)

    Gibaja, Juan F; Subirà, M Eulàlia; Terradas, Xavier; Santos, F Javier; Agulló, Lidia; Gómez-Martínez, Isabel; Allièse, Florence; Fernández-López de Pablo, Javier

    2015-01-01

    Located on the Iberian Mediterranean coast, El Collado is an open-air site where a rescue excavation was conducted over two seasons in 1987 and 1988. The archaeological work excavated a surface area of 143 m2 where 14 burials were discovered, providing skeletal remains from 15 individuals. We have obtained AMS dates for 10 of the 15 individuals by means of the direct dating of human bones. The ranges of the probability distribution of the calibrated dates suggest that the cemetery was used during a long period of time (781-1020 years at a probability of 95.4%). The new dates consequently set back the chrono-cultural attribution of the cemetery from the initial proposal of Late Mesolithic to an older date in the Early Mesolithic. Therefore, El Collado becomes the oldest known cemetery in the Iberian Peninsula, earlier than the numerous Mesolithic funerary contexts documented on the Atlantic façade such as the Portuguese shell-middens in the Muge and Sado Estuaries or the funerary sites on the northern Iberian coast.

  20. The emergence of mesolithic cemeteries in SW Europe: insights from the El Collado (Oliva, Valencia, Spain radiocarbon record.

    Directory of Open Access Journals (Sweden)

    Juan F Gibaja

    Full Text Available Located on the Iberian Mediterranean coast, El Collado is an open-air site where a rescue excavation was conducted over two seasons in 1987 and 1988. The archaeological work excavated a surface area of 143 m2 where 14 burials were discovered, providing skeletal remains from 15 individuals. We have obtained AMS dates for 10 of the 15 individuals by means of the direct dating of human bones. The ranges of the probability distribution of the calibrated dates suggest that the cemetery was used during a long period of time (781-1020 years at a probability of 95.4%. The new dates consequently set back the chrono-cultural attribution of the cemetery from the initial proposal of Late Mesolithic to an older date in the Early Mesolithic. Therefore, El Collado becomes the oldest known cemetery in the Iberian Peninsula, earlier than the numerous Mesolithic funerary contexts documented on the Atlantic façade such as the Portuguese shell-middens in the Muge and Sado Estuaries or the funerary sites on the northern Iberian coast.

  1. Upper-ocean-to-atmosphere radiocarbon offsets imply fast deglacial carbon dioxide release.

    Science.gov (United States)

    Rose, Kathryn A; Sikes, Elisabeth L; Guilderson, Thomas P; Shane, Phil; Hill, Tessa M; Zahn, Rainer; Spero, Howard J

    2010-08-26

    Radiocarbon in the atmosphere is regulated largely by ocean circulation, which controls the sequestration of carbon dioxide (CO(2)) in the deep sea through atmosphere-ocean carbon exchange. During the last glaciation, lower atmospheric CO(2) levels were accompanied by increased atmospheric radiocarbon concentrations that have been attributed to greater storage of CO(2) in a poorly ventilated abyssal ocean. The end of the ice age was marked by a rapid increase in atmospheric CO(2) concentrations that coincided with reduced (14)C/(12)C ratios (Delta(14)C) in the atmosphere, suggesting the release of very 'old' ((14)C-depleted) CO(2) from the deep ocean to the atmosphere. Here we present radiocarbon records of surface and intermediate-depth waters from two sediment cores in the southwest Pacific and Southern oceans. We find a steady 170 per mil decrease in Delta(14)C that precedes and roughly equals in magnitude the decrease in the atmospheric radiocarbon signal during the early stages of the glacial-interglacial climatic transition. The atmospheric decrease in the radiocarbon signal coincides with regionally intensified upwelling and marine biological productivity, suggesting that CO(2) released by means of deep water upwelling in the Southern Ocean lost most of its original depleted-(14)C imprint as a result of exchange and isotopic equilibration with the atmosphere. Our data imply that the deglacial (14)C depletion previously identified in the eastern tropical North Pacific must have involved contributions from sources other than the previously suggested carbon release by way of a deep Southern Ocean pathway, and may reflect the expanded influence of the (14)C-depleted North Pacific carbon reservoir across this interval. Accordingly, shallow water masses advecting north across the South Pacific in the early deglaciation had little or no residual (14)C-depleted signals owing to degassing of CO(2) and biological uptake in the Southern Ocean.

  2. preparation of microgram samples on iron wool for radiocarbon analysis via accelerator mass spectrometry: A closed-system approach

    Science.gov (United States)

    Verkouteren, R. Michael; Klouda, George A.; Currie, Lloyd A.; Donahue, Douglas J.; Jull, A. J. Timothy; Linick, T. W.

    1987-11-01

    A technique has been developed at NBS for the production of high quality targets for radiocarbon analysis by accelerator mass spectrometry (AMS). Our process optimizes chemical yields, ion currents and characterizes the chemical blank. The approach encompasses sample combustion to CO 2, catalytic reduction of CO 2 by Zn to CO, reduction to graphitic carbon on high-purity iron wool and in situ formation of a homogeneous iron-carbon bead; all steps are performed in a closed system. The total measurement system blank and variability are considered in the light of contributions from combustion, iron wool, reduction, bead formation and instrument blank. Additionally, use of this approach provides an increase in throughput, i.e. the effective management of large numbers of samples. Chemical yields for 50-800 μg C samples deposited on 15 mg iron wool were greater than 90%. Integrated 12C - ion currents observed were significant, being 4-64% of those observed in pure graphite. These currents are about an order of magnitude greater than those expected from dilution of graphite with an inert substrate. Isotopic accuracy, precision and blank were assessed by measuring the {14C }/{13C } ratios of a series of targets prepared from dead carbon and oxalic acid (SRM 4990C). Each target was typically measured for one hour; bead consumption was estimated at 5% to 10%. System blank subsequent to combustion was equivalent to (2.2 ± 0.5) μg modern carbon (chemistry + instrument); combustion blank currently stands at (0.4 ± 0.1) (SE, n = 6) μg C.

  3. 76 FR 77831 - 2012 Presidential Candidate Matching Fund Submission Dates and Post Date of Ineligibility Dates...

    Science.gov (United States)

    2011-12-14

    ... 2012 Presidential Candidate Matching Fund Submission Dates and Post Date of Ineligibility Dates To...: Notice of matching fund submission dates and submission dates for statements of net outstanding campaign... fund submission dates for publicly funded 2012 presidential primary candidates. Eligible candidates...

  4. Luminescence dating of ancient Darhad basin, Mongolia

    Science.gov (United States)

    Cheul Kim, Jin; Yi, Sangheon; Lim, Jaesoo; Kim, Ju-Yong

    2016-04-01

    . Thus, age control on existing 14C ages from this site is limited, chronological interpretation based on the 14C ages is still incomplete in Hodon outcrop sediments. OSL (Optically Stimulated Luminescence) is an alternative method for dating to overcome the problems associated with 14C methods. OSL has been extensively used for dating arctic sediments (Thomas et al., 2006; more). Previous optical ages on Darhad paleolake sediments obtained using IRSL (Infrared-stimulated luminescence) on feldspars (Gillespie et al., 2008; Batbaatar et al., 2009). Feldspar has much brighter luminescence than quartz, while the OSL signal of feldspars bleaches at least one order of magnitude slower than the OSL signal of quartz (Godfrey-Smith et al., 1988; Huntly and Lamothe, 2001; Mauz and Bungenstock, 2007; Kim et al., 2012). In glaciofluvial, glaciolacustrine environments, inadequate bleaching of the OSL signal is known to be a potential problem of burial ages (Thomas et al., 2006). OSL dating of permafrost deposits may also involve uncertainty about the inhomogeneous radiation field surrounding the dosimeter and the absorption of ionizing energy alternately by water and ice in a not-constant pore volume (Haeberli et al., 2003). In this study, we test the applicability of quartz OSL dating for the uppermost paleolake sediments in the Hodon outcrop of the Darhad basin. The OSL results were systematically compared with additional radiocarbon ages from wood fragments to conclude the reliability of the OSL dates and to construct intensive chronology for Late-Pleistocene Darhad paleolake. To evaluate the time of recent expansion of the paleolake, the northern piedmont (Talyn outcrop) of the basin was dated by OSL.

  5. The Alpha Magnetic Spectrometer (AMS)

    Energy Technology Data Exchange (ETDEWEB)

    Alcaraz, J.; Alpat, B.; Ambrosi, G.; Anderhub, H.; Ao, L.; Arefiev, A.; Azzarello, P.; Babucci, E.; Baldini, L.; Basile, M.; Barancourt, D.; Barao, F.; Barbier, G.; Barreira, G.; Battiston, R.; Becker, R.; Becker, U.; Bellagamba, L.; Bene, P.; Berdugo, J.; Berges, P.; Bertucci, B.; Biland, A.; Bizzaglia, S.; Blasko, S.; Boella, G.; Boschini, M.; Bourquin, M.; Brocco, L.; Bruni, G.; Buenerd, M.; Burger, J.D.; Burger, W.J.; Cai, X.D.; Camps, C.; Cannarsa, P.; Capell, M.; Casadei, D.; Casaus, J.; Castellini, G.; Cecchi, C.; Chang, Y.H.; Chen, H.F.; Chen, H.S.; Chen, Z.G.; Chernoplekov, N.A.; Chiueh, T.H.; Chuang, Y.L.; Cindolo, F.; Commichau, V.; Contin, A. E-mail: contin@bo.infn.it; Crespo, P.; Cristinziani, M.; Cunha, J.P. da; Dai, T.S.; Deus, J.D.; Dinu, N.; Djambazov, L.; DAntone, I.; Dong, Z.R.; Emonet, P.; Engelberg, J.; Eppling, F.J.; Eronen, T.; Esposito, G.; Extermann, P.; Favier, J.; Fiandrini, E.; Fisher, P.H.; Fluegge, G.; Fouque, N.; Galaktionov, Yu.; Gervasi, M.; Giusti, P.; Grandi, D.; Grimm, O.; Gu, W.Q.; Hangarter, K.; Hasan, A.; Hermel, V.; Hofer, H.; Huang, M.A.; Hungerford, W.; Ionica, M.; Ionica, R.; Jongmanns, M.; Karlamaa, K.; Karpinski, W.; Kenney, G.; Kenny, J.; Kim, W.; Klimentov, A.; Kossakowski, R.; Koutsenko, V.; Kraeber, M.; Laborie, G.; Laitinen, T.; Lamanna, G.; Laurenti, G.; Lebedev, A.; Lee, S.C.; Levi, G.; Levtchenko, P.; Liu, C.L.; Liu, H.T.; Lopes, I.; Lu, G.; Lu, Y.S.; Luebelsmeyer, K.; Luckey, D.; Lustermann, W.; Mana, C.; Margotti, A.; Mayet, F.; McNeil, R.R.; Meillon, B.; Menichelli, M.; Mihul, A.; Mourao, A.; Mujunen, A.; Palmonari, F.; Papi, A.; Park, I.H.; Pauluzzi, M.; Pauss, F.; Perrin, E.; Pesci, A.; Pevsner, A.; Pimenta, M.; Plyaskin, V.; Pojidaev, V.; Postolache, V.; Produit, N.; Rancoita, P.G.; Rapin, D.; Raupach, F.; Ren, D.; Ren, Z.; Ribordy, M.; Richeux, J.P.; Riihonen, E.; Ritakari, J.; Roeser, U.; Roissin, C.; Sagdeev, R.; Sartorelli, G.; Schultz von Dratzig, A.; Schwering, G.; Scolieri, G.; Seo, E.S.; Shoutko, V.

    2002-02-01

    The Alpha Magnetic Spectrometer (AMS) is a large acceptance (0.65 sr m{sup 2}) detector designed to operate in the International Space Station (ISS) for three years. The purposes of the experiment are to search for cosmic antimatter and dark matter and to study the composition and energy spectrum of the primary cosmic rays. A 'scaled-down' version has been flown on the Space Shuttle Discovery for 10 days in June 1998. The complete AMS is programmed for installation on the ISS in October 2003 for an operational period of 3 yr. This contribution reports on the experimental configuration that will be installed on the ISS.

  6. The Alpha Magnetic Spectrometer (AMS)

    CERN Document Server

    Alcaraz, J; Ambrosi, G; Anderhub, H; Ao, L; Arefev, A; Azzarello, P; Babucci, E; Baldini, L; Basile, M; Barancourt, D; Barão, F; Barbier, G; Barreira, G; Battiston, R; Becker, R; Becker, U; Bellagamba, L; Bene, P; Berdugo, J; Berges, P; Bertucci, B; Biland, A; Bizzaglia, S; Blasko, S; Bölla, G; Boschini, M; Bourquin, Maurice; Brocco, L; Bruni, G; Buénerd, M; Burger, J D; Burger, W J; Cai, X D; Camps, C; Cannarsa, P; Capell, M; Casadei, D; Casaus, J; Castellini, G; Cecchi, C; Chang, Y H; Chen, H F; Chen, H S; Chen, Z G; Chernoplekov, N A; Tzi Hong Chiueh; Chuang, Y L; Cindolo, F; Commichau, V; Contin, A; Crespo, P; Cristinziani, M; Cunha, J P D; Dai, T S; Deus, J D; Dinu, N; Djambazov, L; Dantone, I; Dong, Z R; Emonet, P; Engelberg, J; Eppling, F J; Eronen, T; Esposito, G; Extermann, P; Favier, Jean; Fiandrini, E; Fisher, P H; Flügge, G; Fouque, N; Galaktionov, Yu; Gervasi, M; Giusti, P; Grandi, D; Grimm, O; Gu, W Q; Hangarter, K; Hasan, A; Hermel, V; Hofer, H; Huang, M A; Hungerford, W; Ionica, M; Ionica, R; Jongmanns, M; Karlamaa, K; Karpinski, W; Kenney, G; Kenny, J; Kim, W; Klimentov, A; Kossakowski, R; Koutsenko, V F; Kraeber, M; Laborie, G; Laitinen, T; Lamanna, G; Laurenti, G; Lebedev, A; Lee, S C; Levi, G; Levchenko, P M; Liu, C L; Liu, H T; Lopes, I; Lu, G; Lü, Y S; Lübelsmeyer, K; Luckey, D; Lustermann, W; Maña, C; Margotti, A; Mayet, F; McNeil, R R; Meillon, B; Menichelli, M; Mihul, A; Mourao, A; Mujunen, A; Palmonari, F; Papi, A; Park, I H; Pauluzzi, M; Pauss, Felicitas; Perrin, E; Pesci, A; Pevsner, A; Pimenta, M; Plyaskin, V; Pozhidaev, V; Postolache, V; Produit, N; Rancoita, P G; Rapin, D; Raupach, F; Ren, D; Ren, Z; Ribordy, M; Richeux, J P; Riihonen, E; Ritakari, J; Röser, U; Roissin, C; Sagdeev, R; Sartorelli, G; Schwering, G; Scolieri, G; Seo, E S; Shoutko, V; Shoumilov, E; Siedling, R; Son, D; Song, T; Steuer, M; Sun, G S; Suter, H; Tang, X W; Ting, Samuel C C; Ting, S M; Tornikoski, M; Torsti, J; Ulbricht, J; Urpo, S; Usoskin, I; Valtonen, E; Vandenhirtz, J; Velcea, F; Velikhov, E P; Verlaat, B; Vetlitskii, I; Vezzu, F; Vialle, J P; Viertel, Gert M; Vitè, Davide F; Gunten, H V; Wallraff, W; Wang, B C; Wang, J Z; Wang, Y H; Wiik, K; Williams, C; Wu, S X; Xia, P C; Yan, J L; Yan, L G; Yang, C G; Yang, M; Ye, S W; Yeh, P; Xu, Z Z; Zhang, H Y; Zhang, Z P; Zhao, D X; Zhu, G Y; Zhu, W Z; Zhuang, H L; Zichichi, A; Zimmermann, B

    2002-01-01

    The Alpha Magnetic Spectrometer (AMS) is a large acceptance (0.65 sr m sup 2) detector designed to operate in the International Space Station (ISS) for three years. The purposes of the experiment are to search for cosmic antimatter and dark matter and to study the composition and energy spectrum of the primary cosmic rays. A 'scaled-down' version has been flown on the Space Shuttle Discovery for 10 days in June 1998. The complete AMS is programmed for installation on the ISS in October 2003 for an operational period of 3 yr. This contribution reports on the experimental configuration that will be installed on the ISS.

  7. América Latina

    Directory of Open Access Journals (Sweden)

    Marcos Olalla

    2007-01-01

    Full Text Available Este trabajo analiza el sentido intelectualista de la producción literaria modernista de Latinoamérica. Dicho enfoque es revisado en la obra del escritor argentino Manuel Ugarte (1875-1951 El porvenir de América Latina (1910. Nuestra lectura ofrece algunas líneas para la discriminación de las diversas fuentes ideológicas del intelectualismo en el “americanismo literario”. Consideramos en tal sentido la perspectiva historicista con la que Ugarte describe la composición social de América Latina.

  8. Challenges faced when using radiocarbon measurements to estimate fossil fuel emissions in the UK.

    Science.gov (United States)

    Wenger, A.; O'Doherty, S.; Rigby, M. L.; Ganesan, A.; Manning, A.; Allen, G.

    2015-12-01

    Estimating the anthropogenic component of carbon dioxide emissions from direct atmospheric measurements is difficult, due to the large natural carbon dioxide fluxes. One way of determining the fossil fuel component of atmospheric carbon dioxide is the use of radiocarbon measurements. Whilst carbon reservoirs with a reasonably fast carbon exchange rate all have a similar radiocarbon content, fossil fuels are completely devoid of radiocarbon due to their age. Previous studies have 14CO2 (UK) this approach is compromised by the high density of 14CO2 emitting nuclear power plants. Of the 16 nuclear reactors in the UK, 14 are advanced gas cooled reactors, which have one of the highest 14CO2 emission rates of all reactor types. These radiocarbon emissions not only lead to a serious underestimation of the recently added fossil fuel CO2, by masking the depletion of 14C in CO2, but can in fact overshadow the depletion by a factor of 2 or more. While a correction for this enhancement can be applied, the emissions from the nuclear power plants are highly variable, and an accurate correction is therefore not straightforward. We present the first attempt to quantify UK fossil fuel CO2 emissions through the use of 14CO2. We employ a sampling strategy that makes use of a Lagrangian particle dispersion model, in combination with nuclear industry emission estimates, to forecast "good" sampling times, in an attempt to minimize the correction due to emissions from the nuclear industry. As part of the Greenhouse gAs Uk and Global Emissions (GAUGE) project, 14CO2measurements are performed at two measurement sites in the UK and Ireland, as well as during science flights around the UK. The measurement locations have been chosen with a focus on high emitting regions such as London and the Midlands. We discuss the unique challenges that face the determination of fossil fuel emissions through radiocarbon measurements in the UK and our sampling strategy to deal with them. In addition we

  9. Target preparation at the ANTARES AMS Centre

    Energy Technology Data Exchange (ETDEWEB)

    Jacobsen, G.E.; Hua, Q.; Fink, D.; Hotchkis, M.A.C.; Lawson, E.M. [Australian Nuclear Science and Technology Organisation, Lucas Heights, NSW (Australia)

    1996-12-31

    The Antares Accelerator Mass Spectroscopy Centre at ANSTO has two chemistry labs dedicated to preparing targets for measurement. Target preparation encompasses a variety of activities ranging from the curation of incoming samples to the numerous steps involved in the purification and processing of dissimilar samples. One of the two laboratories is set up for the physical and chemical pretreatment of {sup 14}C samples. Treatments include cleaning by sonification, sorting, grinding and sieving, and chemical treatments such as the standard AAA treatment, and solvent extraction. Combustion and graphitization are also carried out in this laboratory. The second laboratory is a clean room and is dedicated to the combustion, hydrolysis and graphitization of {sup 14}C samples as well as the process of the targets for the other isotopes. Combustion is achieved by heating the sample to 900 deg C in the presence of CuO, the resulting gas is purified by passing over Ag and Cu wire at 600 deg C. Graphitization is carried out by reducing the CO{sub 2} with an iron catalyst (600 deg C) in the presence of zinc (400 deg C) and a small amount of hydrogen. Samples such as charcoal, shell bone, wood, sediment, seawater and groundwater, containing 0.3-1 mg or more of original carbon, are processed routinely for radiocarbon analysis. The current {sup 14}C chemistry background for 1 mg carbon is {approx} 0.3 percent of modern carbon (pMC) enabling us to date materials up to 45 000 BP. Samples of 0.5 - 3 mg carbon or more are routinely performed with a precision < 1% At present, procedures are being tested for the treatment of samples containing a minimum of 20 {mu}g original carbon. Such small samples sre more likely to be affected by contamination with modern carbon. These laboratories are also being expanded to cater for the processing of a variety of samples for the measurement of other isotopes, ie {sup 129}I, {sup 10}Be, {sup 36}CI and {sup 26}Al. Initial tests for the extraction of

  10. Study of Rock's Erosion Rate Based on the Determination of 36Cl by AMS

    Institute of Scientific and Technical Information of China (English)

    WANGYue; WUShao-yong; GUANYong-jing; LIUCun-fu; WUWei-ming; JIANGShan

    2003-01-01

    It is very important for science and economy to study the erosion rate of geology. The advanced technology and method may be extended to study the flourishing of the earth's crust and date. Since the measurement of cosmogenic nuclide became reality by AMS, the cosmogenic nuclide becomes more important in geoscience. So the determination of rock's erosion rate with 36Cl by AMS was going on.

  11. Bomb radiocarbon in annual tree rings from Thailand and Australia

    Science.gov (United States)

    Hua, Q.; Barbetti, M.; Jacobsen, G. E.; Zoppi, U.; Lawson, E. M.

    2000-10-01

    We have examined the atmospheric 14C excess in the tropics and the southern hemisphere temperate region in the bomb pulse period, using two sets of cross-dated tree rings. One set was from a medium-sized three-leaf pine ( Pinus kesiya) grown in northwestern Thailand and the other was from a Huon pine ( Lagarostrobos franklinii) grown in northwestern Tasmania, Australia. A total of 48 annual tree rings (24 pairs) from 1952 to 1975 AD were pretreated to alpha-cellulose, combusted to CO 2 and converted to graphite for 14C measurement in the tandem accelerator at ANSTO. Excellent agreement was found between our measured 14C data from tree rings and atmospheric 14C records at similar latitudes. A large depletion of atmospheric 14C for Thailand in 1953-1954 AD was observed. This might be due to a combination of the Suess effect and upwelling in the tropical Indian Ocean. The results also showed the rise and decay of bomb 14C peaks from north to south with a time delay of about 1.5 yr, and the effects of minor atmospheric nuclear tests in the late 1960s and early 1970s. A delay of at least one month for 14C in tree cellulose of Huon pine compared with that in the atmosphere was also found.

  12. 77 FR 12227 - Gross Estate; Election to Value on Alternate Valuation Date; Hearing Cancellation

    Science.gov (United States)

    2012-02-29

    ... Valuation Date; Hearing Cancellation AGENCY: Internal Revenue Service (IRS), Treasury. ACTION: Cancellation... alternate valuation method under section 2032 of the Internal Revenue Code. DATES: The public hearing..., at 10 a.m., in the IRS Auditorium, Internal Revenue Service Building, 1111 Constitution Avenue...

  13. Southwestern (U.S.A. Archaeological Tree-Ring Dating: 1930-1942

    Directory of Open Access Journals (Sweden)

    Stephen E. Nash

    1997-11-01

    Full Text Available Dendrochronology, the science of assigning precise and accurate calendar dates to annual growth rings in trees (Stokes and Smiley 1968, was the first independent dating technique available to prehistorians. Ar­chaeological tree-ring dating came of age at a time when North American archaeologists concerned them­selves primarily with time/space systematics (Willey and Sabloff 1980 and yet had no absolute and inde­pendent dating techniques available to guide their analyses. Histories of archaeology typically have not considered the development of archaeological tree-ring dating in detail. Willey and Sabloff (1980:12 devote one paragraph to the development of Southwestern archaeological tree-ring dating, as does Steibing (1993:261. Trigger (1989:305 considers dendrochronology (in the sense of the Douglass method only in light of radiocarbon dating. Textbooks and regional histories of archaeology do a little better in their treat­ment of dendrochronology, though discussions typically focus on the interpretation of tree-ring dates and not on the developmental history of the technique itself (e.g. Cordell 1984:88-90; Fagan 1991:129-133; Lyon 1996:46; Michels 1973:116; Thomas 1979:190-194. Scott (1966:9 argues that 'the story of the discovery of archaeological tree-ring dating by A E. Douglass and others has been told and retold and is now familiar to scientists and laymen alike'. I beg to differ.

  14. Dilemma posed by uranium-series dates on archaeologically significant bones from Valsequillo, Puebla, Mexico

    Science.gov (United States)

    Szabo, B. J.; Malde, H.E.; Irwin-Williams, C.

    1969-01-01

    In an attempt to date stone artifacts of Early Man excavated from several sites at the Valsequillo Reservoir, a few kilometers south of Puebla, Mexico, Szabo applied the uranium-series method on bone samples known to be either from the same geologic formation as the sites or in direct association with the artifacts. The geologic context of the bones was studied by Malde, and the archaeological sites were excavated by Irwin-Williams. A date determined for bone associated with an artifact (Caulapan sample M-B-6, see below) agrees with a radiocarbon date for fossil mollusks in the same bed and indicates man's presence more than 20 000 years ago. However, some of these bone dates exceed 200 000 years. Because such dates for man in North America conflict with all prior archaeological evidence here and abroad, we are confronted by a dilemna - either to defend the dates against an onslaught of archaeological thought, or to abandon the uranium method in this application as being so much wasted effort. Faced with these equally undesirable alternatives, and unable to decide where the onus fairly lies (if a choice must be made), we give the uranium-series dates as a possible stimulus for further mutual work in isotopic dating of archaeological material. A sample from the Lindenmeier archaeological site north of Fort Collins and another from a Pleistocene terrace along the Arkansas River, both in Colorado, were also dated. ?? 1969.

  15. Expiration Dates Matter

    Medline Plus

    Full Text Available ... Updates Expiration Dates Matter Share Tweet Linkedin Pin it More sharing options Linkedin Pin it Email Print Get Consumer Updates by E-mail | ... Updates RSS Feed If your medicine has expired, it may not provide the treatment you need. In ...

  16. Notiz zum Erscheinungsdatum der "Flora der Gegend um Frankfurt am Main" von Johannes Becker

    OpenAIRE

    Buttler, Karl Peter

    2012-01-01

    Der erste Band von Beckers „Flora der Gegend um Frankfurt am Main“ wurde zwischen dem 14. Oktober und dem 8. November 1827 publiziert. Dank einer Aktennotiz im Archiv der Wetterauischen Gesellschaft für die gesamte Naturkunde in Hanau kann das Erscheinungsdatum auf diesen Zeitraum eingeengt werden. The first volume of Becker’s “Flora der Gegend um Frankfurt am Main” (Flora in the Frankfurt am Main Region) was published between 14 October and 8 November 1827. The publication date can be att...

  17. 14C dating of bone using (gamma) Carboxyglutamic Acid and Carboxyglycine (Aminomalonate)

    Energy Technology Data Exchange (ETDEWEB)

    Southon, J R; Burky, R T; Kirner, D L; Taylor, R E; Hare, P E

    1999-04-27

    Radiocarbon determinations have been obtained on {gamma}-carboxyglutamic acid [Gla] and {alpha}-carboxyglycine (aminomalonate) [Am] as well as acid- and base-hydrolyzed total amino acids isolated from a series of fossil bones. As far as they are aware, Am has not been reported previously in fossil bone and neither Gla nor Am {sup 14}C values have been measured previously. Interest in Gla, an amino acid found in the non-collagen proteins osteocalcin and matrix Gla-protein (MGP), proceeds from the suggestion that it may be preferentially retained and more resistant to diagenetic contamination affecting {sup 14}C values in bones exhibiting low and trace amounts of collagen. The data do not support these suggestions. The suite of bones examined showed a general tendency for total amino acid and Gla concentrations to decrease in concert. Even for bones retaining significant amounts of collagen, Gla (and Am extracts) can yield {sup 14}C values discordant with their expected age and with {sup 14}C values obtained on total amino-acid fractions isolated from the same bone sample.

  18. Two years since SSAMS: Status of {sup 14}C AMS at CAIS

    Energy Technology Data Exchange (ETDEWEB)

    Ravi Prasad, G.V.; Cherkinsky, Alexander; Culp, Randy A.; Dvoracek, Doug K.

    2015-10-15

    The NEC 250 kV single stage AMS accelerator (SSAMS) was installed two years ago at the Center for Applied Isotope Studies (CAIS), University of Georgia. The accelerator is primarily being used for radiocarbon measurements to test the authenticity of natural and bio-based samples while all other samples such as geological, atmospheric, marine and archaeological. are run on the 500 kV, NEC 1.5SDH-1 model tandem accelerator, which has been operating since 2001. The data obtained over a six months period for OXI, OXII, ANU sucrose and FIRI-D are discussed. The mean value of ANU sucrose observed to be slightly lower than the consensus value. The processed blanks on SSAMS produce lower apparent age compared to the tandem accelerator as expected.

  19. Quantification of extraneous carbon during compound specific radiocarbon analysis of black carbon.

    Science.gov (United States)

    Ziolkowski, Lori A; Druffel, Ellen R M

    2009-12-15

    Radiocarbon ((14)C) is a radioactive isotope that is useful for determining the age and cycling of carbon-based materials in the Earth system. Compound specific radiocarbon analysis (CSRA) provides powerful insight into the turnover of individual components that make up the carbon cycle. Extraneous or nonspecific background carbon (C(ex)) is added during sample processing and subsequent isolation of CSRA samples. Here, we evaluate the quantity and radiocarbon signature of C(ex) added from two sources: preparative capillary gas chromatography (PCGC, C(PCGC)) and chemical preparation of CSRA of black carbon samples (C(chemistry)). We evaluated the blank directly using process blanks and indirectly by quantifying the difference in the isotopic composition between processed and unprocessed samples for a range of sample sizes. The direct and indirect assessment of C(chemistry+PCGC) agree, both in magnitude and radiocarbon value (1.1 +/- 0.5 microg of C, fraction modern = 0.2). Half of the C(ex) is introduced before PCGC isolation, likely from coeluting compounds in solvents used in the extraction method. The magnitude of propagated uncertainties of CSRA samples are a function of sample size and collection duration. Small samples collected for a brief amount of time have a smaller propagated (14)C uncertainty than larger samples collected for a longer period of time. CSRA users are cautioned to consider the magnitude of uncertainty they require for their system of interest, to frequently evaluate the magnitude of C(ex) added during sampling processing, and to avoid isolating samples < or = 5 microg of carbon.

  20. Towards constraining the stratosphere-troposphere exchange of radiocarbon: strategies of stratospheric 14CO2 measurements using AirCore

    Science.gov (United States)

    Chen, Huilin; Paul, Dipayan; Meijer, Harro; Miller, John; Kivi, Rigel; Krol, Maarten

    2016-04-01

    Radiocarbon (14C) plays an important role in the carbon cycle studies to understand both natural and anthropogenic carbon fluxes, but also in atmospheric chemistry to constrain hydroxyl radical (OH) concentrations in the atmosphere. Apart from the enormous 14C emissions from nuclear bomb testing in the 1950s and 1960s, radiocarbon is primarily produced in the stratosphere due to the cosmogenic production. To this end, better understanding the stratospheric radiocarbon source is very useful to advance the use of radiocarbon for these applications. However, stratospheric 14C observations have been very limited so that there are large uncertainties on the magnitude and the location of the 14C production as well as the transport of radiocarbon from the stratosphere to the troposphere. Recently we have successfully made stratospheric 14C measurements using AirCore samples from Sodankylä, Northern Finland. AirCore is an innovative atmospheric sampling system, which passively collects atmospheric air samples into a long piece of coiled stainless steel tubing during the descent of a balloon flight. Due to the relatively low cost of the consumables, there is a potential to make such AirCore profiling in other parts of the world on a regular basis. In this study, we simulate the 14C in the atmosphere and assess the stratosphere-troposphere exchange of radiocarbon using the TM5 model. The Sodankylä radiocarbon measurements will be used to verify the performance of the model at high latitude. Besides this, we will also evaluate the influence of different cosmogenic 14C production scenarios and the uncertainties in the OH field on the seasonal cycles of radiocarbon and on the stratosphere-troposphere exchange, and based on the results design a strategy to set up a 14C measurement program using AirCore.

  1. Cosmic ray exposure dating with in situ produced cosmogenic He-3 - Results from young Hawaiian lava flows

    Science.gov (United States)

    Kurz, Mark D.; Colodner, Debra; Trull, Thomas W.; Moore, Richard B.; O'Brien, Keran

    1990-01-01

    Cosmogenic helium contents in a suite of Hawaiian radiocarbon-dated lava flows were measured to study the use of the production rate of spallation-produced cosmogenic He-3 as a surface exposure chronometer. Basalt samples from the Mauna Loa and Hualalai volcanoes were analyzed, showing that exposure-age dating is feasible in the 600-13000 year age range. The data suggest a present-day sea-level production rate in olivine of 125 + or - 30 atoms/g yr.

  2. Radiocarbon Dioxide detection based on Cavity Ring-Down Spectroscopy and a Quantum Cascade Laser

    CERN Document Server

    Genoud, Guillaume; Phillips, Hilary; Dean, Julian; Merimaa, Mikko

    2015-01-01

    Monitoring of radiocarbon ($^{14}$C) in carbon dioxide is demonstrated using mid-infrared spectroscopy and a quantum cascade laser. The measurement is based on cavity ring-down spectroscopy, and a high sensitivity is achieved with a simple setup. The instrument was tested using a standardised sample containing elevated levels of radiocarbon. Radiocarbon dioxide could be detected from samples with an isotopic ratio $^{14}$C/C as low as 50 parts-per-trillion, corresponding to an activity of 5 kBq/m$^3$ in pure CO$_2$, or 2 Bq/m$^3$ in air after extraction of the CO$_2$ from an air sample. The instrument is simple, compact and robust, making it the ideal tool for on-site measurements. It is aimed for monitoring of radioactive gaseous emissions in nuclear power environment, during the operation and decommissioning of nuclear power plants. Its high sensitivity also makes it the ideal tool for the detection of leaks in radioactive waste repositories.

  3. Dating Caral, a preceramic site in the Supe Valley on the central coast of Peru.

    Science.gov (United States)

    Solis, R S; Haas, J; Creamer, W

    2001-04-27

    Radiocarbon dates from the site of Caral in the Supe Valley of Peru indicate that monumental corporate architecture, urban settlement, and irrigation agriculture began in the Americas by 4090 years before the present (2627 calibrated years B.C.) to 3640 years before the present (1977 calibrated years B.C.). Caral is located 23 kilometers inland from the Pacific coast and contains a central zone of monumental, residential, and nonresidential architecture covering an area of 65 hectares. Caral is one of 18 large preceramic sites in the Supe Valley.

  4. A small skull from Flores dated to the 20th century

    DEFF Research Database (Denmark)

    Villa, Chiara; Persson, Liselott; Alexandersen, Verner

    2012-01-01

    A human skull with mandible from the Ngada District on the island of Flores, Indonesia, is described in order to contribute to the knowledge of variation in cranial architecture, which is important in interpretations of evolutionary cerebralisation. The skull was excavated in 1924 and sent...... to the National Museum in Copenhagen. The "Copenhagen Flores" (CF) male skull is radiocarbon-dated and of modern age. The cranium is small, but larger than e.g. Liang Bua skull (LB1) in every measurement. The (CT-scan based) cranial capacity of 1258 ml is normal for modern humans, but somewhat lower than values...

  5. Annotation Method (AM): SE16_AM1 [Metabolonote[Archive

    Lifescience Database Archive (English)

    Full Text Available abase search. Peaks with no hit to these databases are then selected to secondary s...earch using exactMassDB and Pep1000 databases. After the database search processes, each database hits are m...SE16_AM1 PowerGet annotation A1 In annotation process, KEGG, KNApSAcK and LipidMAPS are used for primary dat

  6. Annotation Method (AM): SE41_AM1 [Metabolonote[Archive

    Lifescience Database Archive (English)

    Full Text Available se search. Peaks with no hit to these databases are then selected to secondary sear...ch using EX-HR2 (http://webs2.kazusa.or.jp/mfsearcher/) databases. After the database search processes, each database...SE41_AM1 PowerGet annotation In annotation process, KEGG, KNApSAcK and LipidMAPS are used for primary databa

  7. Annotation Method (AM): SE1_AM1 [Metabolonote[Archive

    Lifescience Database Archive (English)

    Full Text Available base search. Peaks with no hit to these databases are then selected to secondary se...arch using exactMassDB and Pep1000 databases. After the database search processes, each database hits are ma...SE1_AM1 PowerGet annotation A1 In annotation process, KEGG, KNApSAcK and LipidMAPS are used for primary data

  8. Annotation Method (AM): SE29_AM1 [Metabolonote[Archive

    Lifescience Database Archive (English)

    Full Text Available abase search. Peaks with no hit to these databases are then selected to secondary s...earch using exactMassDB and Pep1000 databases. After the database search processes, each database hits are m...SE29_AM1 PowerGet annotation A1 In annotation process, KEGG, KNApSAcK and LipidMAPS are used for primary dat

  9. Annotation Method (AM): SE28_AM1 [Metabolonote[Archive

    Lifescience Database Archive (English)

    Full Text Available abase search. Peaks with no hit to these databases are then selected to secondary s...earch using exactMassDB and Pep1000 databases. After the database search processes, each database hits are m...SE28_AM1 PowerGet annotation A1 In annotation process, KEGG, KNApSAcK and LipidMAPS are used for primary dat

  10. Annotation Method (AM): SE25_AM1 [Metabolonote[Archive

    Lifescience Database Archive (English)

    Full Text Available abase search. Peaks with no hit to these databases are then selected to secondary s...earch using exactMassDB and Pep1000 databases. After the database search processes, each database hits are m...SE25_AM1 PowerGet annotation A1 In annotation process, KEGG, KNApSAcK and LipidMAPS are used for primary dat

  11. Annotation Method (AM): SE40_AM1 [Metabolonote[Archive

    Lifescience Database Archive (English)

    Full Text Available se search. Peaks with no hit to these databases are then selected to secondary sear...ch using EX-HR2 (http://webs2.kazusa.or.jp/mfsearcher/) databases. After the database search processes, each database...SE40_AM1 PowerGet annotation In annotation process, KEGG, KNApSAcK and LipidMAPS are used for primary databa

  12. Annotation Method (AM): SE32_AM1 [Metabolonote[Archive

    Lifescience Database Archive (English)

    Full Text Available abase search. Peaks with no hit to these databases are then selected to secondary s...earch using exactMassDB and Pep1000 databases. After the database search processes, each database hits are m...SE32_AM1 PowerGet annotation A1 In annotation process, KEGG, KNApSAcK and LipidMAPS are used for primary dat

  13. Annotation Method (AM): SE12_AM1 [Metabolonote[Archive

    Lifescience Database Archive (English)

    Full Text Available abase search. Peaks with no hit to these databases are then selected to secondary s...earch using exactMassDB and Pep1000 databases. After the database search processes, each database hits are m...SE12_AM1 PowerGet annotation A1 In annotation process, KEGG, KNApSAcK and LipidMAPS are used for primary dat

  14. Annotation Method (AM): SE14_AM1 [Metabolonote[Archive

    Lifescience Database Archive (English)

    Full Text Available abase search. Peaks with no hit to these databases are then selected to secondary s...earch using exactMassDB and Pep1000 databases. After the database search processes, each database hits are m...SE14_AM1 PowerGet annotation A1 In annotation process, KEGG, KNApSAcK and LipidMAPS are used for primary dat

  15. Annotation Method (AM): SE8_AM1 [Metabolonote[Archive

    Lifescience Database Archive (English)

    Full Text Available base search. Peaks with no hit to these databases are then selected to secondary se...arch using exactMassDB and Pep1000 databases. After the database search processes, each database hits are ma...SE8_AM1 PowerGet annotation A1 In annotation process, KEGG, KNApSAcK and LipidMAPS are used for primary data

  16. Annotation Method (AM): SE9_AM1 [Metabolonote[Archive

    Lifescience Database Archive (English)

    Full Text Available base search. Peaks with no hit to these databases are then selected to secondary se...arch using exactMassDB and Pep1000 databases. After the database search processes, each database hits are ma...SE9_AM1 PowerGet annotation A1 In annotation process, KEGG, KNApSAcK and LipidMAPS are used for primary data

  17. Annotation Method (AM): SE27_AM1 [Metabolonote[Archive

    Lifescience Database Archive (English)

    Full Text Available abase search. Peaks with no hit to these databases are then selected to secondary s...earch using exactMassDB and Pep1000 databases. After the database search processes, each database hits are m...SE27_AM1 PowerGet annotation A1 In annotation process, KEGG, KNApSAcK and LipidMAPS are used for primary dat

  18. Annotation Method (AM): SE33_AM1 [Metabolonote[Archive

    Lifescience Database Archive (English)

    Full Text Available abase search. Peaks with no hit to these databases are then selected to secondary s...earch using exactMassDB and Pep1000 databases. After the database search processes, each database hits are m...SE33_AM1 PowerGet annotation A1 In annotation process, KEGG, KNApSAcK and LipidMAPS are used for primary dat

  19. Annotation Method (AM): SE15_AM1 [Metabolonote[Archive

    Lifescience Database Archive (English)

    Full Text Available abase search. Peaks with no hit to these databases are then selected to secondary s...earch using exactMassDB and Pep1000 databases. After the database search processes, each database hits are m...SE15_AM1 PowerGet annotation A1 In annotation process, KEGG, KNApSAcK and LipidMAPS are used for primary dat

  20. Annotation Method (AM): SE4_AM1 [Metabolonote[Archive

    Lifescience Database Archive (English)

    Full Text Available base search. Peaks with no hit to these databases are then selected to secondary se...arch using exactMassDB and Pep1000 databases. After the database search processes, each database hits are ma...SE4_AM1 PowerGet annotation A1 In annotation process, KEGG, KNApSAcK and LipidMAPS are used for primary data

  1. Annotation Method (AM): SE30_AM1 [Metabolonote[Archive

    Lifescience Database Archive (English)

    Full Text Available abase search. Peaks with no hit to these databases are then selected to secondary s...earch using exactMassDB and Pep1000 databases. After the database search processes, each database hits are m...SE30_AM1 PowerGet annotation A1 In annotation process, KEGG, KNApSAcK and LipidMAPS are used for primary dat

  2. Annotation Method (AM): SE13_AM1 [Metabolonote[Archive

    Lifescience Database Archive (English)

    Full Text Available abase search. Peaks with no hit to these databases are then selected to secondary s...earch using exactMassDB and Pep1000 databases. After the database search processes, each database hits are m...SE13_AM1 PowerGet annotation A1 In annotation process, KEGG, KNApSAcK and LipidMAPS are used for primary dat

  3. Annotation Method (AM): SE11_AM1 [Metabolonote[Archive

    Lifescience Database Archive (English)

    Full Text Available abase search. Peaks with no hit to these databases are then selected to secondary s...earch using exactMassDB and Pep1000 databases. After the database search processes, each database hits are m...SE11_AM1 PowerGet annotation A1 In annotation process, KEGG, KNApSAcK and LipidMAPS are used for primary dat

  4. Annotation Method (AM): SE34_AM1 [Metabolonote[Archive

    Lifescience Database Archive (English)

    Full Text Available abase search. Peaks with no hit to these databases are then selected to secondary s...earch using exactMassDB and Pep1000 databases. After the database search processes, each database hits are m...SE34_AM1 PowerGet annotation A1 In annotation process, KEGG, KNApSAcK and LipidMAPS are used for primary dat

  5. Annotation Method (AM): SE7_AM1 [Metabolonote[Archive

    Lifescience Database Archive (English)

    Full Text Available base search. Peaks with no hit to these databases are then selected to secondary se...arch using exactMassDB and Pep1000 databases. After the database search processes, each database hits are ma...SE7_AM1 PowerGet annotation A1 In annotation process, KEGG, KNApSAcK and LipidMAPS are used for primary data

  6. Annotation Method (AM): SE5_AM1 [Metabolonote[Archive

    Lifescience Database Archive (English)

    Full Text Available base search. Peaks with no hit to these databases are then selected to secondary se...arch using exactMassDB and Pep1000 databases. After the database search processes, each database hits are ma...SE5_AM1 PowerGet annotation A1 In annotation process, KEGG, KNApSAcK and LipidMAPS are used for primary data

  7. Annotation Method (AM): SE2_AM1 [Metabolonote[Archive

    Lifescience Database Archive (English)

    Full Text Available base search. Peaks with no hit to these databases are then selected to secondary se...arch using exactMassDB and Pep1000 databases. After the database search processes, each database hits are ma...SE2_AM1 PowerGet annotation A1 In annotation process, KEGG, KNApSAcK and LipidMAPS are used for primary data

  8. Annotation Method (AM): SE17_AM1 [Metabolonote[Archive

    Lifescience Database Archive (English)

    Full Text Available abase search. Peaks with no hit to these databases are then selected to secondary s...earch using exactMassDB and Pep1000 databases. After the database search processes, each database hits are m...SE17_AM1 PowerGet annotation A1 In annotation process, KEGG, KNApSAcK and LipidMAPS are used for primary dat

  9. Annotation Method (AM): SE20_AM1 [Metabolonote[Archive

    Lifescience Database Archive (English)

    Full Text Available abase search. Peaks with no hit to these databases are then selected to secondary s...earch using exactMassDB and Pep1000 databases. After the database search processes, each database hits are m...SE20_AM1 PowerGet annotation A1 In annotation process, KEGG, KNApSAcK and LipidMAPS are used for primary dat

  10. Annotation Method (AM): SE3_AM1 [Metabolonote[Archive

    Lifescience Database Archive (English)

    Full Text Available base search. Peaks with no hit to these databases are then selected to secondary se...arch using exactMassDB and Pep1000 databases. After the database search processes, each database hits are ma...SE3_AM1 PowerGet annotation A1 In annotation process, KEGG, KNApSAcK and LipidMAPS are used for primary data

  11. Annotation Method (AM): SE35_AM1 [Metabolonote[Archive

    Lifescience Database Archive (English)

    Full Text Available abase search. Peaks with no hit to these databases are then selected to secondary s...earch using exactMassDB and Pep1000 databases. After the database search processes, each database hits are m...SE35_AM1 PowerGet annotation A1 In annotation process, KEGG, KNApSAcK and LipidMAPS are used for primary dat

  12. Annotation Method (AM): SE36_AM1 [Metabolonote[Archive

    Lifescience Database Archive (English)

    Full Text Available abase search. Peaks with no hit to these databases are then selected to secondary s...earch using exactMassDB and Pep1000 databases. After the database search processes, each database hits are m...SE36_AM1 PowerGet annotation A1 In annotation process, KEGG, KNApSAcK and LipidMAPS are used for primary dat

  13. Annotation Method (AM): SE6_AM1 [Metabolonote[Archive

    Lifescience Database Archive (English)

    Full Text Available base search. Peaks with no hit to these databases are then selected to secondary se...arch using exactMassDB and Pep1000 databases. After the database search processes, each database hits are ma...SE6_AM1 PowerGet annotation A1 In annotation process, KEGG, KNApSAcK and LipidMAPS are used for primary data

  14. Annotation Method (AM): SE31_AM1 [Metabolonote[Archive

    Lifescience Database Archive (English)

    Full Text Available abase search. Peaks with no hit to these databases are then selected to secondary s...earch using exactMassDB and Pep1000 databases. After the database search processes, each database hits are m...SE31_AM1 PowerGet annotation A1 In annotation process, KEGG, KNApSAcK and LipidMAPS are used for primary dat

  15. Annotation Method (AM): SE10_AM1 [Metabolonote[Archive

    Lifescience Database Archive (English)

    Full Text Available abase search. Peaks with no hit to these databases are then selected to secondary s...earch using exactMassDB and Pep1000 databases. After the database search processes, each database hits are m...SE10_AM1 PowerGet annotation A1 In annotation process, KEGG, KNApSAcK and LipidMAPS are used for primary dat

  16. Annotation Method (AM): SE26_AM1 [Metabolonote[Archive

    Lifescience Database Archive (English)

    Full Text Available abase search. Peaks with no hit to these databases are then selected to secondary s...earch using exactMassDB and Pep1000 databases. After the database search processes, each database hits are m...SE26_AM1 PowerGet annotation A1 In annotation process, KEGG, KNApSAcK and LipidMAPS are used for primary dat

  17. Examination of background contamination levels for gas counting and AMS target preparation in Trondheim

    DEFF Research Database (Denmark)

    Gulliksen, S.; Thomsen, M.S.

    1992-01-01

    conventional gas proportional counting (GPC) system. We have also studied contamination levels of our target preparation for C-14 accelerator mass spectrometry (AMS) dating in Uppsala. A significant lower background is obtained for Icelandic double spar than for marbles, probably due to a crystal structure...... of the double spar that is more insensitive to contaminating processes. The background for combusted samples is at the same level as for samples of double spar, indicating that additional C-14 contamination due to combustion is negligible. Dates obtained on interstadial samples (T >30 ka BP) by both GPC and AMS...

  18. Truly Blind Dating

    Institute of Scientific and Technical Information of China (English)

    LI LI

    2010-01-01

    @@ Compared to parties,bars and nightclubs,in many countries parks are a site for family leisure and recreation and not a spot to find a date.It is not the case in China.Spouse-hunting fairs in big city parks organized by parents eager to see their children tie the knot have made parks in China a haven for relationshiphunters and their parents.

  19. What's the date of

    Institute of Scientific and Technical Information of China (English)

    刘京西

    2009-01-01

    @@ A:What's the date of our final examination? B:I'm not sure.I'll have to look it up.I'll let youknow tomorrow. A:Thank you. A:我们期末考试是哪一天? B:我也说不清.我给你查查,明天告诉你. A:谢谢你.

  20. Radiocarbon evidence of the Middle to Upper Palaeolithic transition in Southwestern Europe

    Directory of Open Access Journals (Sweden)

    Jöris, Olaf

    2003-12-01

    Full Text Available In the present paper we systematically evaluate the radiometric database underlying the Middle to Upper Palaeolithc transition in southwestern Europe.The different models which attempt to explain the demographical processes underlying this transition rely to a large degree on radiocarbon chronology. We observe that: 1 with increasing age, dates on bone samples show large offsets against those on charcoal, often underestimating these for several thousand years BP and; 2 there is no proof for a persistence of Middle Palaeolithic industries into the time of the earliest Aurignacian in SW Europe. These data contradict the “Ebro- Frontier” model that distinguishes Late Middle Palaeolithic industries in the SW of the Iberian Peninsula from early Aurignacian ones in the NE. On the contrary, our data 3 imply a model of interregional shifts of populations contracting during severe cold and arid phases and expanding under warmer, interstadial conditions, raising ideas on a regional in situ development of the SW European Aurignacian out of Latest Middle Palaeolithic industries made by Neanderthals some 40.0 kyr cal BC.

    Se presenta un estudio sistemático sobre la información radiometrica disponible para la transición Paleolítico Medio-Paleolítico Superior en el Suroeste de Europa. Los diferentes modelos para explicar el proceso demográfico que subyace en esta transición dependen en gran medida de la cronología radiocarbónica. Se observa que: 1 a mayor antiguedad las fechas sobre hueso muestran una mayor desvisación frente a las muestras sobre carbón, a menudo infravalorando estas varios miles de años BP y 2 que no hay pruebas de perduración de industrias de Paleolítico Medio durante las fases tempranas del Auriñaciense en el SW de Europa. Estos datos contradicen el modelo de “frontera del Ebro” que distingue industrias de Paleolítico Medio Tardío en el SW de la Península Ibérica de las industrias del Auriñaciense temprano