Hannover 2016 – wissenschaftliches Programm

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MS: Fachverband Massenspektrometrie

MS 10: Posters III

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 (T_1/2 = 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.