Publikationsrepositorium - Helmholtz-Zentrum Dresden-Rossendorf

We searched for presence of ²⁶Al (t_1/2=0.7 Myr) in deep-sea sediments as a signature for extraterrestrial influx. Our data show an exponential dependence of ²⁶Al with the sample age that is fully compatible with radioactive decay of terrigenic ²⁶Al. The same set of samples demonstrated a clear extraterrestrial ⁶⁰Fe signal between 1.7 and 3.2 Myr ago. Combining our ²⁶Al data with the recently reported ⁶⁰Fe data [1] gives a lower limit for the local interstellar ⁶⁰Fe/²⁶Al isotope ratio. Our Limit of 0.24 is higher than the observed average galactic ⁶⁰Fe/²⁶Al flux ratio of (0.15 + 0.05).It favours the higher ratios deduced from nucleosynthesis models.