The characterization of Last Glacial millennial-Timescale warming phases, known as interstadials or Dansgaard-Oeschger events, requires precise chronologies for the study of paleoclimate records. On the European continent, such chronologies are only available for several Last Glacial pollen and rare speleothem archives principally located in the Mediterranean domain. Farther north, in continental lowlands, numerous high-resolution records of loess and paleosols sequences show a consistent environmental response to stadial-interstadial cycles. However, the limited precision and accuracy of luminescence dating methods commonly used in loess deposits preclude exact correlations of paleosol horizons with Greenland interstadials. To overcome this problem, a radiocarbon dating protocol has been developed to date earthworm calcite granules from the reference loess sequence of Nussloch (Germany). Its application yields a consistent radiocarbon chronology of all soil horizons formed between 47 and 20 ka and unambiguously shows the correlation of every Greenland interstadial identified in isotope records with specific soil horizons. Furthermore, eight additional minor soil horizons dated between 27.5 and 21 ka only correlate with minor decreases in Greenland dust records. This dating strategy reveals the high sensitivity of loess paleoenvironments to Northern Hemisphere climate changes. A connection between loess sedimentation rate, Fennoscandian ice sheet dynamics, and sea level changes is proposed. The chronological improvements enabled by the radiocarbon "earthworm clock" thus strongly enhance our understanding of loess records to a better perception of the impact of Last Glacial climate changes on European paleoenvironments.
Moine, O., Laboratoire de Géographie Physique, Environnements Quaternaires et Actuels, Centre National de la Recherche Scientifique (CNRS), Université Paris-Est-Créteil-Val-de-Marne (UPEC), Meudon, 92195, France; Antoine, P., Laboratoire de Géographie Physique, Environnements Quaternaires et Actuels, Centre National de la Recherche Scientifique (CNRS), Université Paris-Est-Créteil-Val-de-Marne (UPEC), Meudon, 92195, France; Hatté, C., Laboratoire des Sciences Du Climat et de L'Environnement (LSCE), Commissariat à L'Énergie Atomique et Aux ÉNergies Alternatives, Université de Versailles-Saint-Quentin-en-Yvelines, Gif-sur-Yvette, 91198, France; Landais, A., Laboratoire des Sciences Du Climat et de L'Environnement (LSCE), Commissariat à L'Énergie Atomique et Aux ÉNergies Alternatives, Université de Versailles-Saint-Quentin-en-Yvelines, Gif-sur-Yvette, 91198, France; Mathieu, J., Institut National de la Recherche Agronomique, Université Pierre-et-Marie-Curie (UPMC), Sorbonne Universités, Paris, 75005, France; Prud'homme, C., Laboratoire de Géographie Physique, Environnements Quaternaires et Actuels, Centre National de la Recherche Scientifique (CNRS), Université Paris-Est-Créteil-Val-de-Marne (UPEC), Meudon, 92195, France; Rousseau, D.-D., Laboratoire De Météorologie Dynamique, Centre de Formation Sur L'Environnement et la Société, Ecole Normale Supérieure, Paris, 75230, France, Lamont-Doherty Earth Observatory (LDEO), Columbia University, Palisades, NY 10964-1000, United States
Recommended Citation:
Moine O.,Antoine P.,Hatté C.,et al. The impact of Last Glacial climate variability in west-European loess revealed by radiocarbon dating of fossil earthworm granules[J]. Proceedings of the National Academy of Sciences of the United States of America,2017-01-01,114(24)