Every two years, the Geological Society of Finland gives the national Dissertation Prize for the best doctoral thesis in the field. This year, the award was presented in Oulu in connection with the GeoDays event on 13 March 2025 to Katja Bohm for her doctoral thesis entitled Provenance of the pre-Quaternary aeolian dust deposits of East Asia.
New research methods
Katja Bohm’s doctoral thesis explores the study of the source regions of aeolian dust deposits, or deposits transported by wind, from periods when the global climate was warmer than today.
According to the society’s justification for granting the award, Bohm’s doctoral thesis demonstrates that the techniques used to analyse the geochemistry and age of dust-forming minerals, associated with the study of the source regions of aeolian deposits, are effective tools for assessing the cycle of mineral dust. In her thesis, Bohm used a mineral known as rutile for the first time to determine the sources of dust in the Chinese Loess Plateau.
The doctoral thesis demonstrated a link between the regional dust cycle and the global climate.
Climate change in the geological past
The research field represented by Bohm is very topical, as understanding climate change in the geological past and its effects is also important from the perspective of current changes in the climate.
The doctoral thesis comprises three refereed high-quality articles, one of which was approved for publication after the public examination, and a summarising report drawing them together. In the thesis, sediment samples from three different research sites in the Chinese Loess Plateau and its surroundings in East Asia were analysed. The age of the surveyed deposits ranged between 2.6 million and 35 million years.
Funded by the Research Council of Finland, the doctoral thesis was part of Associate Professor Anu Kaakinen’s research project entitled ‘Tracing the winds: releasing the potential of the East Asian dust record of environmental change’.
After defending her doctoral thesis in December 2023, Katja Bohm has continued as a researcher at the University of Helsinki. Now, she has received a two-year grant from the Finnish Cultural Foundation and is leaving for Italy in early June to work as a postdoctoral researcher at the University of Milano-Bicocca.