14C Activity and Global Carbon Cycle Changes over the Past 50,000 Years

K. Hughen, S. Lehman, J. Southon, J. Overpeck, O. Marchal, C. Herring, J. Turnbull

Research output: Contribution to journalArticle

379 Scopus citations

Abstract

A series of 14C measurements in Ocean Drilling Program cores from the tropical Cariaco Basin, which have been correlated to the annual-layer counted chronology for the Greenland Ice Sheet Project 2 (GISP2) ice core, provides a high-resolution calibration of the radiocarbon time scale back to 50,000 years before the present. Independent radiometric dating of events correlated to GISP2 suggests that the calibration is accurate. Reconstructed 14C activities varied substantially during the last glacial period, including sharp peaks synchronous with the Laschamp and Mono Lake geomagnetic field intensity minimal and cosmogenic nuclide peaks in ice cores and marine sediments. Simulations with a geochemical box model suggest that much of the variability can be explained by geomagnetically modulated changes in 14C production rate together with plausible changes in deep-ocean ventilation and the global carbon cycle during glaciation.

Original languageEnglish (US)
Pages (from-to)202-207
Number of pages6
JournalScience
Volume303
Issue number5655
DOIs
StatePublished - Jan 9 2004

ASJC Scopus subject areas

  • General

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    Hughen, K., Lehman, S., Southon, J., Overpeck, J., Marchal, O., Herring, C., & Turnbull, J. (2004). 14C Activity and Global Carbon Cycle Changes over the Past 50,000 Years. Science, 303(5655), 202-207. https://doi.org/10.1126/science.1090300