Details

Autor(en) / Beteiligte

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

Titel

C activity and global carbon cycle changes over the past 50,000 years

Ist Teil von

• Science (American Association for the Advancement of Science), 2004-01, Vol.303 (5655), p.202

Ort / Verlag

American Association for the Advancement of Science

Erscheinungsjahr

2004

Link zum Volltext

Quelle

American Association for the Advancement of Science

Beschreibungen/Notizen

• A series of [sup.14]C 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 [sup.14]C activities varied substantially during the last glacial period, including sharp peaks synchronous with the Laschamp and Hone 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 [sup.14]C production rate together with plausible changes in deep-ocean ventilation and the global carbon cycle during glaciation.