Basu, S;
Stuart, FM;
Schnabel, C;
Klemm, V;
(2007)
Galactic-Cosmic-Ray-Produced in a Ferromanganese Crust: Any Supernova Excess on Earth.
Physical Review Letters
, 98
(14)
10.1103/PhysRevLett.98.141103.
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Abstract
An excess of 60 Fe in 2.4– 3.2 × 10 6 year old ferromanganese crust (237KD) from the deep Pacific Ocean has been considered as evidence for the delivery of debris from a nearby supernova explosion to Earth. Extremely high 3 He / 4 He (up to 6.12 × 10 − 3 ) and 3 He concentrations (up to 8 × 10 9 atoms / g ) measured in 237KD cannot be supernova-derived. The helium is produced by galactic cosmic rays (GCR) and delivered in micrometeorites that have survived atmospheric entry to be trapped by the crust. 60 Fe is produced by GCR reactions on Ni in extraterrestrial material. The maximum 3 He / 60 Fe of 237KD (80–850) is comparable to the GCR 3 He / 60 Fe production ratio (400–500) predicted for Ni-bearing minerals in iron meteorites. The excess 60 Fe can be plausibly explained by the presence of micrometeorites trapped by the crust, rather than injection from a supernova source.
| Type: | Article |
|---|---|
| Title: | Galactic-Cosmic-Ray-Produced in a Ferromanganese Crust: Any Supernova Excess on Earth |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1103/PhysRevLett.98.141103 |
| Publisher version: | https://doi.org/10.1103/PhysRevLett.98.141103 |
| Language: | English |
| Additional information: | This version is the version of record . For information on re-use, please refer to the publisher’s terms and conditions. |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Earth Sciences |
| URI: | https://discovery.ucl.ac.uk/id/eprint/10047658 |
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