Hannover 2010 – wissenschaftliches Programm
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MS: Fachverband Massenspektrometrie
MS 4: Beschleunigermassenspektrometrie und Anwendungen I
MS 4.3: Vortrag
Mittwoch, 10. März 2010, 11:15–11:30, F 428
New approaches investigating production rates of in-situ produced terrestrial cosmogenic nuclides — •Silke Merchel1,2, Régis Braucher1, Lucilla Benedetti1, and Didier Bourlès1 — 1CEREGE, CNRS-IRD-Université Aix-Marseille, F-13545 Aix-en-Provence, France — 2FZD, D-01314 Dresden, Germany
In-situ produced cosmogenic nuclides have proved to be valuable tools for environmental and Earth sciences. However, accurate application of this method is only possible, if terrestrial production rates in a certain environment over a certain time period and their depth-dependence within the exposed material are exactly known. Unfortunately, the existing data and models differ up to several tens of percent. Thus, one of the European project CRONUS-EU goals is the high quality calibration of the 36Cl production rate by spallation at independently dated surfaces. As part of fulfilling this task we have investigated calcite-rich samples from four medieval landslide areas in the Alps: Mont Granier, Le Claps, Dobratsch, and Veliki Vrh (330-1620 m, 1248-1442 AD). For investigating the depth-dependence of the different nuclear reactions, especially, the muon- and thermal neutron-induced contributions, we have analysed mixtures of carbonates and siliceous conglomerate samples - for 10Be, 26Al, and 36Cl - exposed at different shielding depths and taken from a core drilled in 2005 at La Ciotat, France (from surface to 11 m shielding). AMS of 36Cl was performed at LLNL and ETH, 10Be and 26Al at ASTER.
Acknowledgments: Thanks to V. Alfimov, M. Arnold, G. Aumaître, J. Borgomano, R. Finkel, I. Mrak, and J.M. Reitner.