Search for supernova-produced ⁶⁰Fe in the microfossil record

Material distributed into the interstellar medium by supernova explosions can be incorporated into terrestrial archives. After the discovery of live ⁶⁰Fe atoms in 2-3 Myr old layers of a Pacifc Ocean ferromanganese crust (Knie et al., 2004), a confirmation of this signal, as well as a mapping of the signal with high time-resolution is desireable. Another reservoir in which the ⁶⁰Fe signature should have been incorporated in are the fossils of magnetotactic bacteria in ocean sediment. To this end, two sediment cores from the Eastern Equatorial Pacifc were obtained, iron was chemically extracted with high selectivity towards biogenic magnetite, and the extraction procedure was characterized using novel magnetic measurements. The samples were then measured with accelerator mass spectrometry in Garching. Preliminary results for both sediment cores will be reported.