Time resolved 2 million year old supernova activity discovered in Earth's microfossil record
Abstract
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.
Keywords
Cite
@article{arxiv.1710.09573,
title = {Time resolved 2 million year old supernova activity discovered in Earth's microfossil record},
author = {Peter Ludwig and Shawn Bishop and Ramon Egli and Valentyna Chernenko and Boyana Deneva and Thomas Faestermann and Nicolai Famulok and Leticia Fimiani and Jose Manuel Gomez-Guzman and Karin Hain and Gunther Korschinek and Marianne Hanzlik and Silke Merchel and Georg Rugel},
journal= {arXiv preprint arXiv:1710.09573},
year = {2017}
}
Comments
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