Fraktionierung der schweren Edelgase und des Stickstoffs in Mars-Meteoriten als Folge terrestrischer und marsianischer Verwitterungsvorgänge

• Applicant: Dr. Susanne Petra Schwenzer
• Subject Area: Mineralogy, Petrology and Geochemistry
• Term: from 2005 to 2007
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 18223948

The strongest evidence linking the class of SNC meteorites to Mars is the presence of a gas component (noble gases, nitrogen, CO2) in several of them, which agrees with the composition of the Martian atmosphere (within the uncertainties of the atmospheric measurements by Viking). However, Martian meteorites contain also other gas components in addition to Mars atmosphere. A complication in their study is indicated by the comparison of results for Martian meteorites of differing (terrestrial) provenance (hot and cold desert, fall). Elementally fractionated heavy noble gases were found to be incorporated in meteorites from hot deserts, which makes the interpretation of data from these meteorites difficult. In pilot studies we found an elementally fractionated air (EFA) component showing signatures, which can easily be misinterpreted as Martian interior. We plan - through the analysis of nitrogen and noble gases in terrestrial samples, Martian meteorites and samples weathered in laboratory experiments - to determine abundances and signatures of the EFA component in more detail and to obtain clues regarding the incorporation mechanism. Features similar to EFA (such as a low 84Kr/132Xe when compared to the respective parent atmosphere) are observed in the nakhlites and ALH84001 and are possibly due to similar fractionation processes acting on Mars. Thus our results will allow drawing conclusions regarding the influence of weathering on volatiles in Martian rocks on Mars as well as complications caused by contamination processes on Earth.

• DFG Programme: Priority Programmes
• Subproject of: SPP 1115: Mars and the Terrestrial Planets