Marie Katrine Traun

Primary fields of research

I specialize in the field of Solid Earth Geochemistry and Petrology. Within this branch I have focused my studies on stable and radiogenic isotopes in general, and their uses as tracers in subduction zone settings mainly. Additionally, I am very interested in the correlation between geochemical and geophysical processes. Thus, I have directed my focus towards modelling, statistics, programming and simulation. I have taken both my bachelor and master’s degree at the University of Copenhagen.

I completed my master thesis in stable isotope geochemistry of modern arc lavas in September 2019, with T. Waight and E. Pope as main supervisors. In the thesis, I worked with Tl, Li, O and H isotopes, where I explored global trends of a global database, I compiled. Additionally, as a part of the global study, I did a detailed local study of the Payenia region in Argentina (34 to 36S), which involved laboratory work as well, including measurements of O, H and Tl isotopes on bulk rock samples.

I did my bachelor project on Milankovitch cycles, expressed as geochemical composition changes in a shale of the Upper Jurassic in collaboration with Maersk and with C. Bjerrum as main supervisor. In the project, I did spectral analyses of elemental proxies, elemental concentrations analyzed by hand held XRF, and wireline logging data from the drill hole.

Key Areas:

• Stable and Radiogenic Isotopes
• Geochemical Tracers
• Modern Subduction Zones and Plate Tectonics
• Modelling and Programming

Current research

In November 2019, I started a PhD fellow with Nina Søager as main supervisor, funded by the Carlsberg Foundation and the GEOCENTER Grant, on silicic volcanism in the Loicas Trough, Argentina, herein the Tromen Volcano, Domuyo and Varvarco caldera, Southern Andes. The project is expected to be completed in October 2022, and the working title is: Geochemistry and magmatic petrology of silicic volcanism of the southern Andes. Fieldwork and sample collection are conducted in January 2020.

The Loicas Trough is generally characterized by felsic volcanic deposits, testifying to explosive volcanism from the Early Quarternary. Recent seismic tomographic surveys discovered the presence of shallow magma chambers underneath the volcanoes in the Loicas Trough. Thus, the area poses a potential volcanic hazard for the local population. However, limited geochemical research has been conducted in the area, to determine the source of magma and the processes of eruption. In this project, we will therefore study the geochemical variation and petrology of samples from this area.

Concretely, this project has two areas of focus: 1) The magma chambers and eruption styles and 2) the magma sources and the means of melt generation. To address the first point, we will perform geothermobarometry and oxybarometry on feldspar, pyroxene and amphibole phenocrysts, to determine the thermodynamic conditions in the magma chambers. Additionally, using major and trace elements, we will reconstruct the fractionation history of the silicic deposits. To address the second point, we will perform radiogenic and stable isotope measurements, including Pb, Nd, Sr, Tl and potentially O, to determine the contributions of a mantle melting, anatexis and/or assimilation to the magma sources. The first part of the project will focus on the evolved silicic rocks in the area, whereas the second part includes representation of more intermediate and primitive rocks as well, to better constrain the revolutionary trend in the area.

Teaching

• Jessica Hebert BSc thesis (2019 - 2020; co-supervised with Emily C. Pope): On Tl and H-isotopes in modern lavas from Kermadec and Central America, Title in progress.
• TA on geology bachelor courses (2019 – 2020; with Nina Søager): Lithosfæren Geologi og Geokemi (Blok 2, 3^rd semester); Grundlæggende Magmatisk Petrologi (Blok 3, 2^nd semester).

CV

• 2019 – Present: PhD with Nina Søager, University of Copenhagen, DK (Carlsberg Foundation/GEOCENTER Grant).
• 2017 – 2019: MSc in Solid Earth Geochemistry and Petrology, University of Copenhagen, DK.
• 2014 – 2017: BSc in Geology-Geoscience, University of Copenhagen, DK.