Search for supernova-60Fe in Earth’s microfossil record

Search for supernova-60Fe in Earth’s microfossil record

Ludwig, P.; Bishop, S.; Egli, R.; Chernenko, V.; Deneva, B.; Faestermann, T.; Famulok, N.; Fimiani, L.; Guzman, J. M. G.; Hain, K.; Korschinek, G.; Frederichs, T.; Hanzlik, M.; Rugel, G.; Merchel, S.

Supernova (SN) explosions eject copious amounts of material into the interstellar medium. It is possible that supernova ejecta are incorporated into solar system reservoirs. 60Fe is an ideal isotope to search for such a signature, since it is produced in massive stars and can be ejected in their subsequent SN explosions, and has almost no terrestrial background. For this study, the ratio of 60Fe/Fe was determined with AMS using the GAMS setup in Garching, Germany, in a set of samples extracted from two Pacific Ocean sediment cores of 0 to 7 Ma of age. The Fe samples were obtained using a novel chemical extraction technique targeting specifically magnetofossils, chains of magnetite crystals produced by magnetotactic bacteria, and other small-grained Fe-bearing minerals, to prevent signal dilution. Our findings reveal a 60Fe signature in the age range of 1.8-2.5 Ma, which is attributed to input of SN ejecta.

Keywords: accelerator mass spectrometry; supernova

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Publ.-Id: 21391