Cosmochronology is the scientific attempt to determine the age and earliest evolution of the solar system. This can be done by investigating meteorites, which, in most cases, are remnants of asteroidal parent bodies which themselves were processed (e.g. melted, metamorphosed) within the first million years of the 4.56 Byr old solar system. One of the most useful tools to obtain a reasonable time resolution during age dating of early solar system events are short-lived radionuclide systems. By measuring the amount of radiogenic "daughter" isotopes produced by radioactive decay from a short-lived (now extinct) “mother” isotope with a known half-life, cosmochemists can establish a “relative age” for the parental material. This relative age can then be anchored onto an absolute time-scale (established by long-lived chronometry).

One of the most fundamental processes in the early solar system are asteroidal differentiation processes (e.g. melting of asteroids and subsequent formation of asteroidal cores, mantles and crusts). Illuminating the chronology of such asteroidal differentiation processes is therefore one of the major goals of cosmochronology. In the last decade the application of the short-lived 182Hf-182W chronometer (T1/2 = 8.9 Myr) to early solar system materials, especially iron meteorites, provided firm constraints on the timing of core formation (i.e. metal-segregation) and silicate melting as well as metamorphism inside asteroidal parent bodies.

Cosmochemical applications of the department include the investigation of

  •     182Hf / 182W and 146Sm / 142Nd dating of extraterrestrial material
  •     187Re-187Os systematics and platinum group element signatures of meteorites
  •     Measurement of cosmic radiation exposure effects on meteorites (using isotopes with high thermal neutron capture cross-sections, e.g. 149Sm),
  •     Determination of nucleosynthetic isotope anomalies in meteorites (s-, r- and p-process nuclides)

Furthermore, there are extensive cooperations with the Universities of Bonn, Cologne, Göttingen and Tübingen (oxygen, molybdenum and selenium isotopes, HFSE ID, LA-ICP-MS etc.).