Supernova Activity Discovered in Earth's Microfossil Record

Massive stars, which terminate their evolution as core collapse supernovae, are theoretically predicted to eject more than 1E-5 solar masses of the radioisotope 60Fe.

If such an event occurs sufficiently close to our solar system, traces of the supernova debris could be deposited on Earth. Herein, we report a time resolved 60Fe signal residing, at least partially, in a biogenic reservoir. Using accelerator mass spectrometry, this signal was found through the direct detection of live 60Fe atoms contained within secondary iron oxides, among which are magnetofossils, the fossilized chains of magnetite crystals produced by magnetotactic bacteria. The magnetofossils were chemically extracted from two Pacific Ocean sediment drill cores. Our results show that the 60Fe signal onset occurs around 2.6 Ma to 2.8 Ma, near the lower Pleistocene boundary, terminates around 1.7 Ma, and peaks at about 2.2 Ma.

Time resolved 2 million year old supernova activity discovered in Earth’s microfossil record

Peter Ludwig, Shawn Bishop, Ramon Egli, Valentyna Chernenko, Boyana Deneva, Thomas Faestermann, Nicolai Famulok, Leticia Fimiani, Jose Manuel Gomez-Guzman, Karin Hain, Gunther Korschinek, Marianne Hanzlik, Silke Merchel, Georg Rugel
(Submitted on 26 Oct 2017)

Comments: Figures from the Supplementary Information are not included due to file size restrictions. Download the, now open access, original article for those details (see doi)
Subjects: Solar and Stellar Astrophysics (astro-ph.SR); Earth and Planetary Astrophysics (astro-ph.EP)
Journal reference: Proceedings of the National Academies of Science, vol. 113 (2016) pg. 9232-9237
DOI: 10.1073/pnas.1601040113
Cite as: arXiv:1710.09573 [astro-ph.SR] (or arXiv:1710.09573v1 [astro-ph.SR] for this version)
Submission history
From: Shawn Bishop
[v1] Thu, 26 Oct 2017 07:55:48 GMT (5584kb,D)
https://arxiv.org/abs/1710.09573
Astrobiology
Astrochemistry