Dr. Fiona Karen Thiessen

Fiona is now working as a researcher at the European Space Agency (ESA) in Noordwijk, NL

My main research interests are (isotope) geochemistry, planetary sciences and geochronology. 

One of my current research topics is the geological evolution of Eastern Antarctica. About 98 % of Antarctica is covered by a thick ice sheet, which makes it difficult to access bedrocks and study its geology. Therefore, I am analysing rocks collected from Antarctic moraines. More specifically, I am using U-Pb zircon ages. Zircon is one of the most important minerals for radiometric dating due to its resistance to thermal disturbance and weathering. Combing the U-Pb ages with the geochemistry, texture and petrology of the collected rocks will lead to a better understanding of the hidden bedrocks beneath the East Antarctic ice sheet.   

Another research topic is the impact and magmatic history of the Moon. I am investigating lunar impact breccias sampled during the Apollo missions. I analyse their texture and chemical variations, identify microstructures in zircon and phosphates, obtain precise U-Pb ages and investigate diffusion of Pb and U. The combination of these methods will help to link U-Pb ages to real events (i.e. magmatic or impact related) and to get a better understanding of the early impact history of the Moon.

The techniques I use involve SEM, CL-imaging, EBSD, XRF, LA-ICP-MS and SIMS. 

EDUCATION:

• Post-doctoral researcher, 2019, Swedish Museum of Natural History
• Ph.D., 2018, Stockholm University, Sweden
• M.Sc., 2012, University of Münster, Germany