Postdoctoral Fellow, NASA
Cosmochemistry; planetary science; petrography and petrology of meteorites; elemental and isotopic compositions of meteorites; noble gases in meteorites; evolution of differentiated asteroids; evolution of primitive achondrites; accretion processes in the early Solar System
M.Sc., Geology, Georg-August-Universität Göttingen, Germany (1995)
Ph.D., Geochemistry/Cosmochemistry, Max-Planck-Institution for Chemistry, Mainz, Germany (2000)
Contact & Links
- (202) 478-8455
- Department of Terrestrial Magnetism
Carnegie Institution of Washington
5241 Broad Branch Road, NW
Washington, DC 20015-1305
- Curriculum Vitae
For my Ph.D., I investigated the noble gas inventory of enstatite chondrites (ECs) using a customized rare gas mass spectrometer. The project included the calculation of cosmic-ray exposure ages and the determination of trapped noble gases and their systematic distribution in different petrologic types. In addition, I looked into the influence of weathering on the noble gas signature of ECs.
Post doctoral research projects addressed the petrographic properties and the classification of several new meteorites as well as major, minor, and trace elemental concentrations of acapulcoites and lodranites. Methods applied included EMPA and INAA. Some of the new meteorites examined were two HED samples and a peculiar enstatite meteorite with an achondritic texture.
I was also involved in a study searching for shocked quartz in marine sediments from the Triassic-Jurassic (T-J) boundary. The T-J transition is marked by one of the five largest mass extinctions known in Earth’s history. Yet, its trigger is not well established. We examined thin sections of T-J boundary samples from British Columbia for shocked quartz, spinel, or any other mineralogical indicator in order to test the hypothesis of a massive impact.
More recently, I engaged in a project examining the relative abundances of Zr and Hf in a broad spectrum of meteoritic samples, followed by a study of refractory lithophile trace elements in different constituents of the CV3 chondrite Leoville. Analyses were performed applying EMPA and laser ablation ICP-MS techniques. The study of Leoville included a thorough petrographic examination followed by the chemical analysis of selected ingredients.
Some of my most recent work was concerned with differentiated meteorites. First and foremost, I studied in detail the lithological diversity of howardites and the compositional spectrum of their major components. Based on those data, I deduced petrologic implications for the HED parent body. I also started an investigation of the original composition and evolution of ureilites. Key aspects of this latest project were: 1. The formation of reduction rims wrapping around olivine and pyroxene; and 2. The origin of metal within silicates and matrix (the origin of carbon in ureilite vein material is most likely closely related to that of matrix metal). Preliminary results from EMPA work I performed on the ureilite fall Kenna suggest that reduction ceased as quickly as within a matter of days.