Isotopic variations in nature result from radiogenic ingrowth and mass-dependent stable isotope fractionation. In meteorite samples, isotopic variations also result from irradiation processes or may even be vestiges of nucleosynthesis. Studying the isotope compositions of elements in geological materials can therefore shed new light on e.g., the formation of the solar system and its planets, terrestrial geodynamic processes, environmental changes and the timing of geological events.
Multicollector - inductively coupled plasma - mass spectrometry (MC-ICP-MS) provides a unique opportunity to perform precise isotope ratio measurements for a wide range of elements. The versatility of MC-ICP-MS stems in part from the fact that most elements can be well ionized and from its relatively stable mass bias that enables comparatively straight forward stable isotope analyses.
The geochemistry/cosmochemistry group hosts a ThermoElectron Neptune MC-ICP-MS system. Until the new clean lab facilities at Cologne are constructed, the instrument is operated at the Steinmann-Institut, Poppelsdorfer Schloss, in Bonn.
Radiogenic isotope systems routinely employed in our lab include Lu-Hf, Rb-Sr, Sm-Nd and U-Pb that are applied, for instance, to study processes in the Earth's mantle, the evolution of the Early Earth or dating metamorphism by garnet geochronology. Furthermore, the short-lived Hf-W and Nb-Zr chronometers are applied to extraterrestrial materials.
Stable isotope analyses (B, Fe, Cu, Zn and Cd) are applied to problems in cosmochemistry, igneous and marine geochemistry, and soil sciences.
Another prominent analytical tool employed at Cologne is the precise determination of trace element abundances by isotope dilution. Currently our toolbox includes the high field strength elements Zr, Hf, Ta and W. Isotope dilution protocols for analyzing some other elements are under development.
Finally, we investigate nucleosynthetic anomalies and irradiation effects in meteorite samples using for example Cd, Ba, Sm and W isotopes.