Atlantic Radiocarbon Calibration using framework forming cold water corals
Final Report Abstract
Radiocarbon calibration based on uranium-thorium dated cold-water corals provides an excellent opportunity to develop a marine radiocarbon calibration and simultaneously study ocean circulation, and water mass movement. A high-resolution data set of combined 14C and U/Th data was derived for South Atlantic water masses for the past 32000 years in direct comparison with a radiocarbon prediction using a general ocean circulation model. Cold-water corals off Angola match previously published records from the equatorial Atlantic and near Tasmania, thus yielding the possibility of a 14C calibration for the South Atlantic. This record confirmed a systematic aging of water masses up to the Glacial Maximum and a renewal of water masses during the Bølling/Allerød climate warming 13600 years ago. In contrast to the South Atlantic and modeling results, the results for thermocline waters north of the Azores Front show strong fluctuations and mostly well-ventilated water masses. During the Bølling- Allerød (B/A) stadial, renewal of water masses also occurs at greater depths and throughout the entire Atlantic. Our results suggest that the North and South Atlantic must be considered as acting separately during the Maximum Glaciation and subsequent climate warming and B/A. Initial studies of the temperature history of the intermediate waters indicate a much stronger influence of polar waters and further narrow the range of well-ventilated water masses, presumably confined to the boundary between the subtropical and subpolar waters of the North Atlantic. Finally, a parallel study of present-day radiocarbon patterns in the Atlantic indicates similar processes. The Azores Front still represents the boundary for water exporting carbon and heat from south to north almost unaffected by anthropogenic changes, while deep water formation leads to southward export in the western Atlantic.
Publications
- Coralline ∆1 4C and εNd Data from the Atlantic Ocean. IPODS-OC3 Workshop Cambridge, September 6th to 9th, 2018, Cambridge University
F. Hemsing, M. Lausecker, T. Krengel, S. Therre , J. M. Link, L. Bonneau, P. Blaser, A.-M. Wefing, C. Colin, N. Tisnerat-Laborde5, G. dos Santos, F. Eynaud, D. van Rooij, C. Wienberg, D. Hebbeln, N. Frank
- Radiocarbon Calibration using Atlantic Cold-Water Corals. 23rd Radiocarbon Conference, Trondheim 2018
Norbert Frank, Freya Hemsing, Steffen Therre, Elvira Beisel, Carla Roesch, Guaciara, M. dos Santos, Ronny Friedrich
- Radiocarbon variability in northeast Atlantic intermediate waters during the past six decades recorded in coldwater corals. 23rd Radiocarbon Conference, Trondheim 2018
Nadine Tisnérat Laborde, Eric Douville, Cécile Gonzalez-Roubaud, Norbert Frank, Paolo Montagna, Jean Carlos Montero-Serrano, Pierre Sabatier, Jason Hall-Spencer, Lucile Boneau, Furu Mienis, Christophe Colin
- The modern Northeast Atlantic Radiocarbon Content viewed along a basin transect from 29°- 61°N. European Geoscience Union Annual Meeting 2020 Session OS1.7
Norbert Frank, Markus Miltner, Steffen Therre, Marleen Lausecker, Nadine Tisnerat-Laborde, Paolo Montagna, and Ronny Friedrich
(See online at https://doi.org/10.5194/egusphere-egu2020-13803) - 2021., Insights into Atlantic thermocline seawater temperatures from cold-water corals since the last glacial, PhD Thesis, Institut für Umweltphysik, Universität Heidelberg
Lausecker, M.
(See online at https://doi.org/10.11588/heidok.00030347) - Heidelberg Radiocarbon Lab - Established a new carbon dioxide extraction line for carbonate samples, Radiocarbon, 63, Nr 3, 2021, p 915–924
Therre, S., Proß, L., Friedrich, R., Trüssel, M., Frank, N.
(See online at https://doi.org/10.1017/RDC.2021.28)
