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Marine20—The Marine Radiocarbon Age Calibration Curve (0–55,000 cal BP)
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- Timothy J Heaton, Peter Köhler, Martin Butzin, Edouard Bard, Ron W Reimer, William E N Austin, Christopher Bronk Ramsey, Pieter M Grootes, Konrad A Hughen, Bernd Kromer, Paula J Reimer, Jess Adkins, Andrea Burke, Mea S Cook, Jesper Olsen, Luke C Skinner
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- Journal:
- Radiocarbon / Volume 62 / Issue 4 / August 2020
- Published online by Cambridge University Press:
- 12 August 2020, pp. 779-820
- Print publication:
- August 2020
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- Article
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The concentration of radiocarbon (14C) differs between ocean and atmosphere. Radiocarbon determinations from samples which obtained their 14C in the marine environment therefore need a marine-specific calibration curve and cannot be calibrated directly against the atmospheric-based IntCal20 curve. This paper presents Marine20, an update to the internationally agreed marine radiocarbon age calibration curve that provides a non-polar global-average marine record of radiocarbon from 0–55 cal kBP and serves as a baseline for regional oceanic variation. Marine20 is intended for calibration of marine radiocarbon samples from non-polar regions; it is not suitable for calibration in polar regions where variability in sea ice extent, ocean upwelling and air-sea gas exchange may have caused larger changes to concentrations of marine radiocarbon. The Marine20 curve is based upon 500 simulations with an ocean/atmosphere/biosphere box-model of the global carbon cycle that has been forced by posterior realizations of our Northern Hemispheric atmospheric IntCal20 14C curve and reconstructed changes in CO2 obtained from ice core data. These forcings enable us to incorporate carbon cycle dynamics and temporal changes in the atmospheric 14C level. The box-model simulations of the global-average marine radiocarbon reservoir age are similar to those of a more complex three-dimensional ocean general circulation model. However, simplicity and speed of the box model allow us to use a Monte Carlo approach to rigorously propagate the uncertainty in both the historic concentration of atmospheric 14C and other key parameters of the carbon cycle through to our final Marine20 calibration curve. This robust propagation of uncertainty is fundamental to providing reliable precision for the radiocarbon age calibration of marine based samples. We make a first step towards deconvolving the contributions of different processes to the total uncertainty; discuss the main differences of Marine20 from the previous age calibration curve Marine13; and identify the limitations of our approach together with key areas for further work. The updated values for ΔR, the regional marine radiocarbon reservoir age corrections required to calibrate against Marine20, can be found at the data base http://calib.org/marine/.
Contributors
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- By Sonia Ancoli-Israel, Ragnar Asplund, Michel Billiard, Theresa M. Buckley, Rohit Budhiraja, Robert N. Butler, Daniel J. Buysse, Scott S. Campbell, Daniel P. Cardinali, Julie Carrier, Cynthia L. Comella, Jana R. Cooke, Pietro Cortelli, Agnès Demazieres, Glenna A. Dowling, Luigi Ferini-Strambi, Philip R. Gehrman, Nalaka Sudheera Gooneratne, David S. Hallegua, Patrick J. Hanly, David G. Harper, Orla P. Hornung, Magdolna Hornyak, Michal Karasek, Milton Kramer, Andrew D. Krystal, Malcolm H. Lader, Rachel Leproult, Kenneth L. Lichstein, Andrea H.S. Loewen, Rémy Luthringer, Laurin J. Mack, Evelyn Mai, Atul Malhotra, Jennifer L. Martin, Judy Mastick, Monique A.J. Mets, Andrew A. Monjan, Timothy H. Monk, Daniel Monti, Jaime M. Monti, Patricia J. Murphy, C. Ineke Neutel, Eric A. Nofzinger, Seithikurippu R. Pandi-Perumal, Scott B. Patton, Donald B. Penzien, Max H. Pittler, Giora Pillar, Marc J. Poulin, Louis J. Ptácek, Stuart F. Quan, Jeanetta C. Rains, Megan E. Ruiter, Bruce D. Rybarczyk, Colin M. Shapiro, Vijay Kumar Sharma, D. Warren Spence, Kai Spiegelhalder, Luc Staner, Stephanie A. Studenski, Nikola N. Trajanovic, Eve Van Cauter, Gregory S. Vander Wal, Joris C. Verster, Aleksandar Videnovic, Matthew P. Walker, Daniel J. Wallace, David K. Welsh, David P. White, Barbara Wider, Theresa B. Young, Stefano Zanigni
- Edited by S. R. Pandi-Perumal, Jaime M. Monti, Universidad de la República, Uruguay, Andrew A. Monjan, National Institute on Aging, Bethesda, Maryland
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- Book:
- Principles and Practice of Geriatric Sleep Medicine
- Published online:
- 04 August 2010
- Print publication:
- 26 November 2009, pp ix-xii
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Contributors
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- By Jennifer Alvarez, Ananda B. Amstadter, Metin Başoğlu, David M. Benedek, Charles C. Benight, George A. Bonanno, Evelyn J. Bromet, Richard A. Bryant, Barbara Lopes Cardozo, M. L. Somchai Chakkraband, Claude Chemtob, Roman Cieslak, Lauren M. Conoscenti, Joan M. Cook, Judith Cukor, Carla Kmett Danielson, JoAnn Difede, Charles DiMaggio, Anja J.E. Dirkzwager, Cristiane S. Duarte, Jon D. Elhai, Diane L. Elmore, Yael L.E. Errera, Julian D. Ford, Carol S. Fullerton, Sandro Galea, Freya Goodhew, Neil Greenberg, Lindsay Greene, Linda Grievink, Michael J. Gruber, Sumati Gupta, Johan M. Havenaar, Alesia O. Hawkins, Clare Henn-Haase, Kimberly Eaton Hoagwood, Christina W. Hoven, Sabra S. Inslicht, Krzysztof Kaniasty, Ronald C. Kessler, Rachel Kimerling, Richard V. King, Rolf J. Kleber, Jessica Mass Levitt, Brett T. Litz, Maria Livanou, Katelyn P. Mack, Paula Madrid, Shira Maguen, Paul Maguire, Donald J. Mandell, Charles R. Marmar, Andrea R. Maxwell, Shannon E. McCaslin, Alexander C. McFarlane, Thomas J. Metzler, Summer Nelson, Yuval Neria, Elana Newman, Thomas C. Neylan, Fran H. Norris, Carol S. North, Lawrence A. Palinkas, Benjaporn Panyayong, Maria Petukhova, Betty Pfefferbaum, Marleen Radigan, Beverley Raphael, James Rodriguez, G. James Rubin, Kenneth J. Ruggiero, Ebru Şalcıoğlu, Nancy A. Sampson, Arieh Y. Shalev, Bruce Shapiro, Laura M. Stough, Prawate Tantipiwatanaskul, Warunee Thienkrua, Phebe Tucker, J. Blake Turner, Robert J. Ursano, Bellis van den Berg, Peter G. van der Velden, Frits van Griensven, Miranda Van Hooff, Edward Waldrep, Philip S. Wang, Simon Wessely, Leslie H. Wind, C. Joris Yzermans, Heidi M. Zinzow
- Edited by Yuval Neria, Columbia University, New York, Sandro Galea, University of Michigan, Ann Arbor, Fran H. Norris
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- Book:
- Mental Health and Disasters
- Published online:
- 07 May 2010
- Print publication:
- 20 July 2009, pp xi-xvi
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AMS Radiocarbon Dating of Ancient Iron Artifacts: A New Carbon Extraction Method in Use at LLNL
- Andrea C Cook, Jeffrey Wadsworth, John R Southon
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- Journal:
- Radiocarbon / Volume 43 / Issue 2A / 2001
- Published online by Cambridge University Press:
- 18 July 2016, pp. 221-227
- Print publication:
- 2001
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A new sealed double tube combustion method was developed at Lawrence Livermore National Laboratory (LLNL) to extract carbon from modern steels and ancient iron artifacts. Iron samples were chemically pretreated with 10% nitric acid, vacuum sealed in 6 mm quartz tubes with CuO, vacuum sealed again inside 9 mm quartz tubes, and combusted at 1000 °C for a minimum of 10 hr. The resulting CO2 was graphitized routinely using hydrogen reduction (Vogel et al. 1989). After the initial phase of development, carbon yields of 100% were consistently obtained. The activities of two modern high carbon steels (treated as process blanks, manufactured using only coal as the carbon source) were determined to be 0.0077 ± 0.0009 (n = 12, ± 1 σ) for a 1.3% C steel and 0.0090 ± 0.0038 (n = 12, ± 1 σ) for a 1.9% C steel, indicating that very little contamination is introduced during the sample preparation process. Since the Iron Age began less than 5000 years ago, these background uncertainties should introduce errors of no more than ±30 years to the radiocarbon ages of actual artifacts. Two ancient iron artifacts of known date were analyzed and demonstrate that the new methodology can be used to obtain the correct date of manufacture for iron objects, provided that they are made exclusively using charcoal that was contemporaneous with the manufacture of the artifact. Since only 1 mg of carbon is required for accelerator mass spectrometry (AMS), very small iron samples can now be analyzed (50 mg of a 2.0% C iron or 1 g of a 0.1% C iron). We anticipate that this methodology will be particularly useful to archeologists who currently have to rely on context to date iron artifacts.