Sektion 2.5: Geodynamische Modellierung

Project Opportunities

In case you are interested in joining our section for the duration of an internship, thesis, PhD or Postdoc project, we have listed a few representative project opportunities and funding options below (work in progress - more to follow). Of course, we are also open for any great project idea that you may have. Our contact details can be found here.

Plume temperatures versus core-mantle boundary temperatures

Plumes are regions of hot mantle material that are thought to ascend from the core-mantle boundary (CMB). A temperature contrast between plumes and surrounding mantle originates where the plumes form. However, there is a discrepancy between the low excess temperature of many plumes (Bao et al., 2022) and the much higher estimated temperature contrast across the thermal boundary layer at the base of the mantle (Lobanov et al., 2021). This discrepancy can be partially explained by a larger adiabatic temperature drop of plumes across the mantle, compared to ambient mantle (Albers and Christensen, 1996). To address this issue we plan to extract plume temperatures from the output of numerical models of mantle convection with variable CMB temperature. We will mainly look at existing model output, however, there is also the option to perform new model runs. If realistic plume temperatures and CMB temperatures turn out to be incompatible for these models, it will point towards additional complexity needed, such as chemically different material at the base of the mantle with plumes only rising from the top of the thermal boundary layer, or enhanced mixing of ambient mantle into plumes.

Suitable for: Internship, Bachelor or Master Thesis. Complexity and scope of the project can be adjusted depending on background and interest.

Requirements: Basic understanding of physical processes. Some background in geodynamics and previous experience with coding would be helpful.

Supervisors:  Charitra Jain (GFZ Potsdam), Bernhard Steinberger (GFZ Potsdam), in collaboration with Sergey Lobanov (GFZ Potsdam)

Useful papers:

Albers, M., and Christensen, U.R. (1996), The excess temperature of plumes rising from the core-mantle boundary, Geophys. Res. Lett., 23, 3567-3570,

Bao, X., Lithgow-Bertelloni, C.R., Jackson, M.G., and Romanowicz, B. (2022), On the relative temperatures of Earth’s volcanic hotspots and mid-ocean ridges, Science, 375, 57-61,

Lobanov, S.S., Speziale, S., and Brune, S. (2021), Modelling Mie scattering in pyrolite in the laser-heated diamond anvil cell: Implications for the core-mantle boundary temperature determination, Phys. Earth Planet. Inter., 318, 106773,

Modelling of geoid variations

The geoid represents the deviation of the "shape" of the Earth (mean sea level; conceptually extended beneath continents) from its equilibrium shape. These deviations are caused by excess or missing masses in the Earth interior: An excess mass attracts water and causes a "hill" in the geoid and vice versa. Accordingly, the geoid can give information about mass distribution in the Earth interior. In this project, we will use simple models of mass distributions, guided by other information, such as seismic tomography, plate reconstructions, mantle plume locations to compute the geoid, following an established methodology (Hager and Richards, 1989). We have shown that with such rather simple and plausible models we can explain the Indian Ocean Geoid Low quite well (Steinberger et al., 2021). Here we would like to apply this approach to other features of the geoid. In case of interest, the project is also extendable, for example towards geodynamic forward modelling of the mass distributions in the Earth interior and corresponding geoid features.

Suitable for: Someone who would like to get a first hands-on experience in studying the Earth interior, for example during an internship, or for a Bachelor or Master Thesis.

Requirements: An interest in science. Basic experience in geophysics and coding would be useful.

Supervisor:  Bernhard Steinberger (GFZ Potsdam)

Useful papers:

Steinberger, B., Rathnayake, S., Kendall, E. (2021): The Indian Ocean Geoid Low at a plume-slab overpass. - Tectonophysics, 817, 229037.

Hager, B.H., Richards, M.A. (1989): Long-wavelength variations in Earth's geoid: physical models and dynamical implications. - Philos. Trans. R. Soc. Lond. Ser. A: Math. Phys. Sci. 328, 309–327.

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