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