Mainz 2017 – wissenschaftliches Programm
MS 6.5: Vortrag
Mittwoch, 8. März 2017, 15:45–16:00, RW 2
New data for cosmogenic 53Mn and 60Fe in iron meteorites — •Thomas Smith1, Ingo Leya1, Silke Merchel2, Georg Rugel2, Stefan Pavetich3, Michaela Fröhlich3, Anton Wallner3, Keith Fifield3, Stephen Tims3, Gunther Korschinek4, and Thomas Faestermann4 — 1University of Bern, Switzerland — 2HZDR, Dresden, Germany — 3ANU, Canberra, Australia — 4TUM, Munich, Germany
Cosmogenic nuclides in meteorites can provide information on cosmic ray exposure (CRE) histories. In space, meteoroids are irradiated by galactic cosmic ray particles, inducing the production of cosmogenic nuclides (10Be, 26Al, 36Cl, 41Ca, 53Mn, 60Fe). Meteorites are routinely measured for 10Be, 26Al, and 36Cl. However the database for 53Mn and 60Fe is scarce due to the low availability of high-MV accelerators and the debate over the half-lives of 53Mn and 60Fe. We report new 53Mn and 60Fe data for iron meteorites measured at Canberra (53Mn, 60Fe) and Munich (60Fe). Among these radionuclides, 53Mn has the longest half-life, thus is least influenced by terrestrial ages. The advantage of 53Mn and 60Fe isotopes is that only two (Fe, Ni) and one (Fe) target element(s), respectively, dominate production, overcoming the problem of inhomogeneous S and P distribution. Our new 60Fe data almost doubles that present in the literature. We measured 53Mn in seven subsamples of the iron meteorite Twannberg. The new 53Mn and 60Fe data, with 10Be, 26Al, 36Cl, 41Ca and the noble gases, will better constrain the CRE histories of meteorites and will also serve as benchmarks to validate and improve Monte-Carlo model calculations.