Hannover 2016 – wissenschaftliches Programm
MS 10.1: Poster
Donnerstag, 3. März 2016, 16:30–19:00, Empore Lichthof
Supernova-produced 60Fe in Earth’s microfossil record — •Peter Ludwig1, Shawn Bishop1, Ramon Egli2, Valentyna Chernenko1, Boyana Deneva1, Thomas Faestermann1, Leticia Fimiani1, José Manuel Gómez-Guzmán1, Karin Hain1, Gunther Korschinek1, Marianne Hanzlik3, Silke Merchel4, and Georg Rugel4 — 1Physik Department TUM, Garching — 2ZAMG, Wien — 3Chemie Department TUM, Garching — 4HZDR, Dresden
It is possible for a nearby supernova (SN) explosion to deposit a fraction of its ejecta on Earth. Due to the lack of significant anthropogenic and cosmogenic background, 60Fe (T1/2 = 2.6 Ma) is perfectly suited to serve as a radioactive tracer of recent SN events. The ratio of 60Fe/Fe was measured in over 100 samples extracted from two sediment cores from the Eastern Equatorial Pacific. The AMS samples were produced using a carefully tuned chemical leaching technique that specifically targets fine-grained iron-oxides, such as magnetofossils. Magnetofossils are the remains of magnetosome chains, built up by magnetotactic bacteria, which are abundantly present in our sediment, as shown by magnetic analysis and electron microscopy. The AMS samples were measured at the GAMS setup at the Maier-Leibnitz-Laboratory in Garching, where the use of a gas-filled magnet for isobaric suppression provides a sensitivity of 60Fe/Fe≈ 5· 10−17. Our results reveal a 60Fe signature over a time-range of about 1.7-2.7 Ma, which is attributed to the deposition of SN debris.