Accelerator mass spectrometry radiocarbon stratigraphies in deep Labrador Sea cores: paleoceanographic implications

1994 ◽  
Vol 31 (1) ◽  
pp. 38-47 ◽  
Author(s):  
Guoping Wu ◽  
Claude Hillaire-Marcel
Keyword(s):  
Mass Spectrometry ◽  
Surface Layer ◽  
Age Differences ◽  
Accelerator Mass Spectrometry ◽  
Labrador Sea ◽  
Western Boundary ◽  
Mixing Models ◽  
Foraminiferal Species ◽  
History Of ◽  
Apparent Age

Foraminiferal accelerator mass spectrometry (AMS) 14C ages and benthic–planktonic age differences in surface-layer sediments of Labrador Sea are influenced by bioturbation and by changes in the relative abundance of foraminiferal species carrying the 14C signal. Using benthic-mixing models we demonstrate that inverse benthic–planktonic age differences can be generated when the effect of benthic mixing and abundance change exceeds apparent age differences between surface water and deep water. AMS 14C ages obtained put constraints on the timing of major paleoceanographic changes in the basin, notably on the history of the Western Boundary Undercurrent, which was clearly reinitiated during the mid-deglaciation and intensified during the last 2–3 ka.

scholarly journals Fire History of a Giant African Baobab Evinced by Radiocarbon Dating

Radiocarbon ◽  
2010 ◽  
Vol 52 (2) ◽  
pp. 717-726 ◽  
Author(s):  
Adrian Patrut ◽  
Diana H Mayne ◽  
Karl F von Reden ◽  
Daniel A Lowy ◽  
Robert van Pelt ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
South Africa ◽  
Accelerator Mass Spectrometry ◽  
Radiocarbon Dating ◽  
Fire History ◽  
Adansonia Digitata ◽  
Entire Area ◽  
History Of

The article reports the first radiocarbon dating of a live African baobab (Adansonia digitata L.), by investigating wood samples collected from 2 inner cavities of the very large 2-stemmed Platland tree of South Africa. Some 16 segments extracted from determined positions of the samples, which correspond to a depth of up to 15–20 cm in the wood, were processed and analyzed by accelerator mass spectrometry (AMS). Calibrated ages of segments are not correlated with their positions in the stems of the tree. Dating results indicate that the segments originate from new growth layers, with a thickness of several centimeters, which cover the original old wood. Four new growth layers were dated before the reference year AD 1950 and 2 layers were dated post-AD 1950, in the post-bomb period. Formation of these layers was triggered by major damage inside the cavities. Fire episodes are the only possible explanation for such successive major wounds over large areas or over the entire area of the inner cavities of the Platland tree, able to trigger regrowth.

scholarly journals Radiocarbon Dating with the University of Washington Accelerator Mass Spectrometry System

Radiocarbon ◽  
1986 ◽  
Vol 28 (2A) ◽  
pp. 237-245 ◽  
Author(s):  
Pieter M Grootes ◽  
Minze Stuiver ◽  
George W Farwell ◽  
Donald D Leach ◽  
Fred H Schmidt
Keyword(s):  
Mass Spectrometry ◽  
Organic Carbon ◽  
Accelerator Mass Spectrometry ◽  
Dry Valleys ◽  
Tandem Accelerator ◽  
University Of Washington ◽  
Annual Growth Rings ◽  
History Of ◽  
Atmospheric Changes ◽  
The University

The University of Washington FN tandem accelerator mass spectrometry (AMS) system has been used in a series of 14C studies. 1) The 14C concentrations in annual growth rings for 1962, 1963, and 1964 of a Sitka spruce, each divided into ten sequential segments, were measured; a full and rapid response of tree-ring cellulose to atmospheric changes in 14CO2 is indicated, with a delay, if any, of not more than three weeks. 2) The C concentrations in two chemical fractions of dissolved organic carbon and in two fractions (by size) of particulate organic carbon were measured for Amazon River samples from several locations. All contain bomb carbon, but the amounts differ significantly. 3) Algae samples from lakes in the dry valleys of Antarctica were dated in order to assist in the reconstruction of the climatic history of Antarctica. 4) Background studies indicate that the contribution of the AMS system itself to the observed 14C concentrations is equivalent to an age of ca 60,000 14C yr BP; for a prepared sample of 5mg of carbon the background corresponds to ca 50,000 years.

scholarly journals How Clean is Ultrafiltration Cleaning of Bone Collagen?

Radiocarbon ◽  
2007 ◽  
Vol 49 (2) ◽  
pp. 193-200 ◽  
Author(s):  
Matthias C Hüls ◽  
Pieter M Grootes ◽  
Marie-Josée Nadeau
Keyword(s):  
Mass Spectrometry ◽  
Molecular Weight ◽  
Age Differences ◽  
Accelerator Mass Spectrometry ◽  
Bone Collagen ◽  
Pig Skin ◽  
Molecular Weight Cutoff ◽  
Freeze Dried ◽  
Carbon Mass

As part of our bone dating development, we have tested the ultrafiltration of bone gelatin using 2 different filters—Vivaspin 20™ (VS20), a polyethersulfone, and Vivaspin 15R™ (VS15R), a cellulose, both with a 30,000 molecular weight cutoff—and bone collagen from dated samples ranging in age from 1.5 to >50 kyr BP. A direct accelerator mass spectrometry (AMS) measurement yielded radiocarbon concentrations of ∼0.5 pMC (∼42 kyr) for the polyethersulfone, ∼14.4–17.5 pMC (∼15.6–14 kyr) for the cellulose, and ∼107.4 pMC for the glycerin. The filters were cleaned before use similar to the Oxford protocol (Bronk Ramsey et al. 2004), and a series of freeze-dried archaeological bone gelatin samples and a modern pig-skin gelatin were passed through VS20 and VS15R filters (Vivascience™). We recovered both the eluent (<30-kD fraction) and the liquid that stayed above the filter (>30 kD) in order to obtain a carbon mass and isotope balance. While the >30-kD collagen fraction that is usually selected for AMS analysis does not appear to be significantly contaminated, measurements show significant age differences between the eluent <30 kD and the unfiltered bone collagen, indicating that, despite cleaning, both glycerin and filter still give off contaminants in the eluent. Ultrafiltration with young collagen from pig skin generally confirms these results for the <30-kD fraction but also shows the possibility of small contaminations in the >30-kD fraction. Until a contamination with filter carbon of the >30-kD collagen fraction can be excluded, we would recommend caution in the use of ultrafiltration for cleaning bone collagen with VS20 or VS15R ultrafilters.

AMS Radiocarbon Dates of Pyroclastic-Flow Deposits on the Southern Slope of the Kuju Volcanic Group, Kyushu, Japan

Radiocarbon ◽  
2016 ◽  
Vol 59 (2) ◽  
pp. 483-488 ◽  
Author(s):  
Mitsuru Okuno ◽  
Shinji Nagaoka ◽  
Yoko Saito-Kokubu ◽  
Toshio Nakamura ◽  
Tetsuo Kobayashi
Keyword(s):  
Mass Spectrometry ◽  
Pyroclastic Flow ◽  
Accelerator Mass Spectrometry ◽  
Radiocarbon Dating ◽  
Southern Slope ◽  
Radiocarbon Dates ◽  
Ams Radiocarbon Dating ◽  
Volcanic Group ◽  
Lava Domes ◽  
History Of

AbstractThe Kuju volcanic group, located in central Kyushu, Japan, consists of small stratovolcanoes and lava domes. To refine the eruptive history of the group, we conducted accelerator mass spectrometry (AMS) radiocarbon dating of charcoal fragments from three pyroclastic-flow (PF) deposits on the southern slope. The obtained 14C dates are consistent with the geomorphology, stratigraphy, and thermoluminescence (TL) ages. The Handa PF deposits, which are products of the largest eruption of the group, were dated to ~53.5 ka BP. The Shirani and Muro PF deposits, which are block-and-ash flows, were dated to 44 to >50 cal ka BP and 35–39 cal ka BP, respectively. These ages can be correlated with TL ages for lava domes. This study demonstrates that the lava domes and associated PF deposits formed after the Handa eruption.

scholarly journals Radiocarbon Dating Cremated Bone: A Case Study Comparing Laboratory Methods

Radiocarbon ◽  
2019 ◽  
Vol 61 (5) ◽  
pp. 1581-1591 ◽  
Author(s):  
Helene Agerskov Rose ◽  
John Meadows ◽  
Sanne W L Palstra ◽  
Christian Hamann ◽  
Mathieu Boudin ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Accelerator Mass Spectrometry ◽  
Radiocarbon Dating ◽  
Measuring Process ◽  
Laboratory Methods ◽  
Sample Mass ◽  
High Ranking ◽  
History Of ◽  
Replicate Measurements

ABSTRACTRadiocarbon (14C) results on cremated bone are frequently published in high-ranking journals, but 14C laboratories employ different pretreatment methods as they have divergent perceptions of what sources of contaminants might be present. We found pretreatment protocols to vary significantly between three laboratories (Brussels [RICH], Kiel [KIA], and Groningen [CIO]), which all have a long history of dating cremated bone. We present a case study of 6 sets of replicate dates, to compare laboratory pretreatment protocols, and a further 16 sets of inter-laboratory replicate measurements, which compare specific steps of the conversion and measuring process. The 14C results showed dates to be reproducible between the laboratories and consistent with the expected archaeological chronology. We found that differences in pretreatment, conversion to CO2 and accelerator mass spectrometry (AMS) measurement to have no measurable influence on the majority of obtained results, suggesting that any possible diagenesis was probably restricted to the most soluble ≤5% of each sample, as this proportion of the sample mass was removed under all laboratory protocols.

Sediments, sedimentation rates, and environments, southeast Baffin Shelf and northwest Labrador Sea, 8–26 ka

1994 ◽  
Vol 31 (1) ◽  
pp. 90-103 ◽  
Author(s):  
J. T. Andrews ◽  
K. Tedesco ◽  
W. M. Briggs ◽  
L. W. Evans
Keyword(s):  
Mass Spectrometry ◽  
Accelerator Mass Spectrometry ◽  
Planktonic Foraminifera ◽  
Ice Sheet ◽  
Shelf Break ◽  
Laurentide Ice Sheet ◽  
Labrador Sea ◽  
Baffin Island ◽  
Near Surface ◽  
Detrital Carbonate

Ten 14C-dated cores are described from the Labrador Sea, continental slope, and Hatton and Resolution basins on the southeast Baffin Shelf. Based on sharply defined detrital carbonate layers in the Labrador Sea cores, we propose that the Laurentide Ice Sheet reached the shelf break at both 20 and 15 14C ka (24.3 and 18.2 sidereal ka) and contributed significant sediment to the northwest Labrador Sea both times; the flux was ± 720 kg/(m2∙ka) during these periods of maximum ice extent. The Laurentide Ice Sheet retreated from its 15 ka position at the shelf break to the inner shelf between 14 and 12 14C ka. Ice-proximal conditions, recognized by relatively light δ18O on near-surface planktonic foraminifera, high detrital carbonate, and benthic foraminiferal faunas (dominated by Elphidium excavatum forma clavata; Cassidulina reniforme), prevailed until at least 10 14C ka. The ice readvanced toward Resolution Basin and across part of Hatton Basin at 11 14C ka. Accelerator mass spectrometry dates on core tops indicate that deposition on the shelf virtually ceased by 7 ka and was very low in the northwest Labrador Sea throughout the Holocene. Downcore accelerator mass spectrometry dates indicate that during deglaciation, the loci of depocentres shifted in response to changes in the position of the ice margin. On the southeast Baffin Island shelf net sediment fluxes at the sea floor reached values of over 3000 kg/(m2∙ka) between 12 and 10 14C ka, of which nearly half was detrital carbonate, principally calcite.

‘Made … With Admirable Artistry’: The Context, Manufacture and History of a Taíno Belt

2013 ◽  
Vol 93 ◽  
pp. 287-317 ◽  
Author(s):  
Joanna Ostapkowicz
Keyword(s):  
Mass Spectrometry ◽  
Sixteenth Century ◽  
Dominican Republic ◽  
Accelerator Mass Spectrometry ◽  
Spiritual Power ◽  
Wealth Status ◽  
History Of ◽  
Cotton Belt ◽  
Woven Structure ◽  
Collection History

Vienna's Museum für Völkerkunde holds in its collections a rare sixteenth-century Taíno cotton belt from Hispaniola (today's Dominican Republic/Haiti) – one of only two surviving Taíno cotton artefacts to feature European ‘exotics’, including mirrors, jet beads and brass. This complex woven structure – a wearable work of art – offers a rare window on to one of the most prestigious of Taíno valuables, a personal ornament that literally wrapped the wearer in wealth, status and spiritual power. The paper charts the original context and use of Taíno belts, and provides a detailed account of the Vienna belt's collection history, its construction and its chronological placement (radiocarbon-dated using accelerator mass spectrometry (AMS) to ad 1475–1635). The question of how and when the European materials were incorporated into the belt is explored, critically engaging the entangled histories of association between the two.

scholarly journals Hiatus in Prehistoric Chronology of the Cis-Baikal Region, Siberia: Pattern or Artifact?

Radiocarbon ◽  
2007 ◽  
Vol 49 (1) ◽  
pp. 123-129 ◽  
Author(s):  
Yaroslav V Kuzmin
Keyword(s):  
Mass Spectrometry ◽  
Accelerator Mass Spectrometry ◽  
Baikal Region ◽  
Critical Evaluation ◽  
Burial Grounds

The problem of a hiatus at about 6100–5300 BP (about 4900–4200 cal BC) in the prehistoric chronology of the Cis-Baikal region in Siberia is discussed. Based on a critical evaluation of existing evidence, there was no discontinuity found in the cultural sequence between the Kitoi and Serovo/Glazkovo complexes of the Neolithic, and the proposed “hiatus” may be an artifact based on underestimation of solid data. Conventional 14C dates are presented that were generated in the 1980s to early 2000s for Cis-Baikal prehistoric burial grounds, and were later dated by the accelerator mass spectrometry (AMS).

scholarly journals 14C INTERCOMPARISON EXERCISE ON BONES AND IVORY SAMPLES: IMPLICATIONS FOR FORENSICS

Radiocarbon ◽  
2021 ◽  
pp. 1-12
Author(s):  
G Quarta ◽  
M Molnár ◽  
I Hajdas ◽  
L Calcagnile ◽  
I Major ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
International Atomic Energy Agency ◽  
Accelerator Mass Spectrometry ◽  
Reference Curve ◽  
Nuclear Testing ◽  
Energy Agency ◽  
Widespread Application ◽  
Intercomparison Exercise ◽  
High Degree ◽  
Data Calibration

ABSTRACT The application of accelerator mass spectrometry radiocarbon (AMS 14C) dating in forensics is made possible by the use of the large excursion of the 14C concentration in the post-WWII terrestrial atmosphere due to nuclear testing as a reference curve for data calibration. By this approach high-precision analyses are possible on samples younger than ∼70 years. Nevertheless, the routine, widespread application of the method in the practice of forensics still appears to be limited by different issues due to possible complex interpretation of the results. We present the results of an intercomparison exercise carried out in the framework of an International Atomic Energy Agency (IAEA) CRP-Coordinated Research Project between three AMS laboratories in Italy, Hungary, and Switzerland. Bone and ivory samples were selected with ages spanning from background (>50 ka) to 2018. The results obtained allow us to assess the high degree of reproducibility of the results and the remarkable consistency of the experimental determinations.

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