Identifying Dansgaard/Oeschger Cycles during the Penultimate Glacial
Final Report Abstract
The North Atlantic realm witnessed rapid and high-amplitude millennial-scale climate variations during the last glacial known as Dansgaard – Oeschger (D/O). These sudden events of strong NH warming lasted a few hundred to at most a few thousand years and interrupted cold stadials abruptly. Temperatures in Greenland increased by up to ~15°C within few decades. Following a slow decrease in temperature the final return to stadial conditions was rapid again. D/O events have been recognized world-wide, although their influence vanishes with increasing distance from the North Atlantic. The forcing mechanisms of D/O events are intensively debated, but there is general consensus that the interplay between extended Northern Hemisphere ice sheets and the Atlantic Overturning Circulation (AMOC) plays a central role. So far, however, robust knowledge of D/O events is only available for the last glacial period, from ice in Greenland and from a number of other proxy records. However, information about D-O events during earlier glacial periods and their absence would be extremely useful to obtain a more comprehensive picture of these enigmatic warmings. The aim of this study is to test if the D/O events, which occurred during the penultimate glacial, where different from those of the last glacial. We present replicated stable isotope records of speleothems from the northern rim of the European Alps. This location has previously shown to provide reliable evidence of D-O events for the last glacial period. Between ~202 and ~133 ka before present this record reveals three distinct eight ka-long periods without D/O variability. As during the last glacial period, these periods stopped when the global sea-level rose, suggesting that the triggering mechanism of D/O-events may is indeed sensitive to the continental ice-sheet extent.
Publications
- 2017, Radiocarbon dating of a speleothem record of palaeoclimate for Angkor, Cambodia, Radiocarbon 59, 1873 – 1890
Hua, Q., Cook, D., Fohlmeister, J., Penny, D., Bishop, P., Buckman, S.
(See online at https://doi.org/10.1017/RDC.2017.115) - 2017, Winter precipitation changes during the Medieval Climate Anomaly and the Little Ice Age in arid Central Asia, Quaternary Science Reviews 178, 24 – 36
Fohlmeister, J., Plessen, B., Dudashvilli, A., Tjallingii, R., Wolff, C., Cheng, H.
(See online at https://doi.org/10.1016/j.quascirev.2017.10.026) - 2018, Carbon and oxygen isotope fractionation in the water-calcitearagonite system, Geochimica et Cosmochimica Acta 235, 127-139
Fohlmeister, J., Arps, J., Spötl, C., Schröder-Ritzrau, A., Plessen, B., Günter, C., Frank, N., Trüssel, M.
(See online at https://doi.org/10.1016/j.gca.2018.05.022) - 2018, Evidence of warm and humid interstadials in central Europe during MIS 3 revealed by a multi-proxy speleothem record, Quaternary Science Reviews 200, 276 – 286
Weber, M., Scholz, D., Schröder-Ritzrau, A., Deininger, M., Spötl, C., Lugli, F., Mertz-Kraus, R., Jochum, K. P., Fohlmeister, J., Stumpf C.F., Riechelmann, D.C.F.
(See online at https://doi.org/10.1016/j.quascirev.2018.09.045) - 2018, Precipitation changes over the eastern Bolivian Andes inferred from speleothem (δ18O) records for the last 1400 years, Earth and Planetary Science Letters 494, 124-134
Apaéstegui, J., Cruz, F. W., Vuille, M., Fohlmeister, J., Espinoza, J. C., Sifeddine, A., Strikis, N., Guyot, J. L., Ventura, R., Cheng, H., Edwards, L.
(See online at https://doi.org/10.1016/j.epsl.2018.04.048) - 2018, Reconstruction of late Holocene autumn/winter precipitation variability in SW Romania from a high-resolution speleothem trace element record, Earth and Planetary Science Letters 499, 122-133
Warken, S., Fohlmeister, J., Schröder-Ritzrau, A., Constantin, S., Spötl, C., Gerdes, A., Esper, J., Frank, N., Arps, J., Terente, M., Riechelmann, D.F.C., Mangini, A., Scholz, D.
(See online at https://doi.org/10.1016/j.epsl.2018.07.027) - 2019, Evaluating the potential of tree-ring methodology for cross-dating of three annually laminated stalagmites from Zoolithencave (SE Germany), Quaternary Geochronology 52, 37 – 50
Riechelmann, D.F.C., Fohlmeister, J., Kluge, T., Jochum, K.P., Richter, D.K., Deininger, M., Friedrich, R., Frank., N., Scholz., D.
(See online at https://doi.org/10.1016/j.quageo.2019.04.001) - 2019, STAlagmite dating by Radiocarbon (star): a software tool for reliable and fast age depth modelling, Quaternary Geochronology 51, 120 – 129
Fohlmeister, J., Lechleitner, F.A.
(See online at https://doi.org/10.1016/j.quageo.2019.02.008) - Modelling the 14C bomb-pulse in young speleothems using a soil carbon continuum model, Geochimica et Cosmochemica Acta 261, 342 – 367
Markowska, M., Fohlmeister, J., Treble., P., Baker, A., Andersen., M. S., Hua, Q.
(See online at https://doi.org/10.1016/j.gca.2019.04.029) - SISAL working group members including Fohlmeister, J., 2019, Evaluating model outputs using integrated global speleothem records of climate change since the last glacial, Climate of the Past 15, 1557–1579
Comas-Bru., L., Harrison, S.P., Werner, M., Rehfeld, K., Scroxton, N., Veiga-Pires, C.
(See online at https://doi.org/10.5194/cp-15-1557-2019)
