Berlin 2014 – wissenschaftliches Programm
MS 7.4: Vortrag
Mittwoch, 19. März 2014, 17:45–18:00, DO24 1.205
Detecting Supernova Dust on the Earth’s Sea Floor with AMS — •Jenny Feige1, Anton Wallner2, Dieter Breitschwerdt3, L. Keith Fifield2, Gunther Korschinek4, Silke Merchel5, Georg Rugel5, Peter Steier1, Steve Tims2, Stephan R. Winkler1, and Robin Golser1 — 1University of Vienna, Austria — 2ANU Canberra, Australia — 3TU Berlin, Germany — 4TUM, Germany — 5HZDR, Germany
An 60Fe anomaly was detected with accelerator mass spectrometry (AMS) - a very sensitive method to measure extremely low isotopic ratios - in a 2 Myr old layer of a ferromanganese crust (Knie et al., 2004).
This signal is assumed to be of supernova origin and might be linked to the observation of our solar system being located in a region of thin, hot interstellar medium. This region, called the Local Bubble, was presumably formed by multiple supernova explosions starting ∼14 Myr ago. Calculations suggest that at least one of these supernovae occured close enough to the solar system to leave a detectable 60Fe trace on Earth.
New AMS measurements are performed in deep-sea sediments from the Pacific Ocean. An international collaboration of different AMS facilities searches for signatures of the long-lived radionuclides 26Al, 53Mn, and 60Fe in a time range from 1.7 to 3.1 Myr. Magnetostratigraphic dating of the samples is confirmed by measurements of the cosmogenic radionuclide 10Be. All 10Be and 26Al measurements are finished, 53Mn and 60Fe is in progress. First results will be presented and discussed.