Frankfurt 2014 – wissenschaftliches Programm
HK 40.5: Vortrag
Donnerstag, 20. März 2014, 15:30–15:45, HZ 5
Search for Supernova-produced 60Fe in the Earth’s Fossil Record — •Shawn Bishop1, Peter Ludwig1, Ramon Egli2, Valentyna Chernenko1, Thomas Faestermann1, Nicolai Famulok1, Leticia Fimiani1, Thomas Frederichs3, Jose Gomez1, Karin Hain1, Marianne Hazlik4, Gunther Korschinek1, Silke Merchel5, and Georg Rugel5 — 1TU München, Physik Department — 2ZAMG, Wien — 3Universität Bremen, Geowissenschaften — 4TU München, Fakultät für Chemie — 5HZDR, Dresden
Approximately 1.8 to 2.8 Myr before the present our planet was subjected to the debris of a supernova explosion. The terrestrial proxy for this event was the discovery of live atoms of 60Fe in a deep-sea ferromanganese crust [Knie et al., Phys. Rev. Lett. (2004)]. The signature for this supernova event should also reside in magnetite (Fe3O4) magnetofossils produced by magnetotactic bacteria extant at the time of the Earth-supernova interaction; these bacteria were and are ubiquitous in all ocean sediments. We have conducted accelerator mass spectrometry (AMS) measurements, searching for live 60Fe in the magnetofossil component of a Pacific Ocean sediment core (ODP Core 848); additional AMS measurements are now ongoing with a second sediment core (ODP Core 851) in which we expect to find a higher 60Fe signal. This talk will present the current preliminary status of our 60Fe search results for both sediment cores.