Publikationsrepositorium - Helmholtz-Zentrum Dresden-Rossendorf

For the age range from 1.5 to 4 Myr ago we found in deep ocean ferromanganese crusts an excess concentration in terms of 53Mn/Mn of about 4 · 10−14 over that expected for cosmogenic production. We conclude that this 53Mn is of supernova origin because it is detected in the same time window, about 2.5 Myr ago, where 60Fe has been found earlier. This overabundance confirms unambiguously the supernova (SN) origin of that 60Fe. For the first time supernova-formed 53Mn has been detected and it is the second positively verified radioisotope from the same supernovae. The ratio 53Mn/60Fe of about 12 is consistent with that expected for a SN with a 11 - 25 M⊙ progenitor mass and
solar metallicity. A fit over the whole range until 10 Myr shows also a second increase of 53Mn/Mn in the range around 6 Myr matching
recent 60Fe detection in sediments at ANU.