Holocene speleothem-based climate record for the SW Mediterranean area (Middle Atlas; Morocco)
Zusammenfassung der Projektergebnisse
The main aims of the DFG project were to (i) reconstruct the Holocene climate of northwest Morocco by using speleothem archive data and to (ii) place the data in a climate dynamical context with respect to published work from the North Atlantic area. We have reached these goals by investigating aragonitic (and subordinate calcitic) speleothems from two caves in the Middle Atlas of Morocco. Our work included a logistically complex monitoring program performed over a two-year-period. Focusing on the hitherto rarely used aragonitic speleothems, we developed a new model for the interpretation of isotope data and trace elements in aragonite speleothems. Applying these data in a larger context has led to the interpretation of the Mg and Sr elemental record in the context of effective rainfall from 619-1962 AD. The data compiled in the context of this study have important climate implications concerning the evolution of the North Atlantic Oscillation. In a forthcoming paper, we, using the state-of-the-art earth system model COSMOS, combine modelling data of the NAO-index being subject to non-stationary behaviour expressed by changes in the latitudinal or longitudinal position of the NAO sea level pressure centres. This in turn affects North Atlantic/European rainfall/temperature patterns. Oxygen isotope data from the Moroccan speleothems combined with Mg/Ca records from the German Bunker Cave sheds light on the NAO dynamics in the period 2.5 and 11.5 kyr BP. It appears that the ocean exerted a stronger impact on NAO sea level pressure patterns as a consequence of non-linear effects due to the interaction of the presence of the Laurentide ice sheet and its melt water.
Projektbezogene Publikationen (Auswahl)
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2012, The magnesium isotope record of cave carbonate archives, Climate of the Past, 8, 1849-1867
Riechelmann, S., D. Buhl, A. Schröder-Ritzrau, D. F. C. Riechelmann, D. K. Richter, H. B. Vonhof, J. Wassenburg, A. Geske, C. Spötl, And A. Immenhauser
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2012. Climate and cave control on Pleistocene/Holocene calcite-to-aragonite transitions in speleothems from Morocco: Elemental and isotopic evidence, Geochimica et Cosmochimica Acta, 92, 23-47
Wassenburg, J.A., Immenhauser, A., Richter, D.K., Jochum, K.P., Fietzke, J., Deininger, M., Goos, M., Scholz, D. And Sabaoui, A.
