BSc and MSc Projects

Our group is offering numerous BSc and MSc projects that cover a wide spectrum of subjects in geodynamics and its numerical modelling. Short descriptions, prerequisite knowledge and contact information are listed below. These are indicative and many more projects are possible, depending on candidates interests.

Mantle Dynamics

Mixing in Earth's mantle by vigorous, three-dimensional non-Newtonian convection

From geochemical measurements we know that Earth's mantle is chemically very heterogeneous, and most likely this heterogeneity is caused mainly by the introduction of chemically-layered slabs at subduction zones, which then get stirred and mixed by mantle convection. Thus, the details of stirring and mixing in the mantle are of great interest to both geochemists and geophysicists, but have so far been studied mainly by two-dimensional calculations. In this project, three-dimensional numerical convection simulations will be performed to study mixing in three-dimensional convection, focusing particularly on the effect of non-Newtonian viscosity (i.e., strain rate is not necessarily proportional to stress).

Contact: Paul Tackley
Project type: BSc
Major: Geophysics or Physics

The fate of silicates exsolved from the Earth’s core

Recent studies indicate that the geodynamo may have been largely powered by the exsolution of light elements (such as SiO₂ or MgO) from the core [O’Rourke&Stevenson, nature 2016; Hirose+, nature 2017]. However, the fate of exsolved silicates in the mantle remains unknown. In this project, the entrainment of a layer of SiO₂ at the core-mantle boundary by mantle convection, as well as the dispersal of SiO₂ through the mantle will be studied using two-dimensional geodynamic simulations. Any accumulation of SiO₂ near ~1,500 km depth, i.e. the level of neutral buoyancy for SiO₂, may account for abundant seismic scatterers in the mid mantle [Kaneshima&Helffrich, science 1999].

Contact: Paul Tackley
Project type: BSc or MSc
Major: Geophysics, Geology or Physics

Slab graveyards at the core-mantle boundary

Most slabs appear to sink to the bottom of the mantle, where they are heated up by the core, their chemically-distinct components (crust and residue) may segregate, they may cause the formation up upwelling hot plumes, and they interact with the post-perovskite phase transition. High-resolution three-dimensional numerical models will be used to study these processes and the results will be related to detailed seismic studies.

Contact: Paul Tackley
Project type: MSc
Major: Geophysics or Physics

Dynamics of the Lithosphere

Investigating the geodynamic evolution of the Red Sea Rift

Figure 1. Geologic map of the Arabian plate (Aldaajani et al., 2021). This map includes the tectonic setting and major structural features of the volcanic fields (Harrats) and surrounding area.

The Red Sea and its flanking continental crusts offers a unique opportunity to understand the evolution of divergent plate margins within the continental realm. The Red Sea rifting architecture (Fig.1) differs dramatically along strike (Szymenski et al., 2016), with the northern segment of the RS characterized by hyper-extended crust lacking significant magmatism, coastal escarpment and an axial trough with asymmetrical lithospheric necking and dike intrusions. In contrast, the southern Red Sea rift segment is an example of a magma-rich margin and narrow continental rifting system, that formed in old and stable lithosphere with a thick elastic thickness of the southern Arabian margin (Chen et al., 2015). Understanding the controlling processes of these architectural differences is a fundamental key to the Red Sea rifting evolution and global continental rifting processes. The driving forces of the Red Sea are still debatable (Aldaajani et al., 2021), whether is driven by the emplacement of the Afar plume or far field forces, such as the Neo-Tethys slab pull. Thus, this project focuses on building three dimensional model to simulate the geodynamic evolution the Red Sea under the given plate boundaries condition, Afar potential effect, and western Arabian lithospheric rheology.
_{References:
Aldaajani, T. Z., Almalki, K. A., & Betts, P. G. (2021). Plume versus slab-pull: example from the Arabian Plate. Frontiers in Earth Science, 9, 700550.‏
Chen, B., Kaban, M. K., El Khrepy, S., & Al‐Arifi, N. (2015). Effective elastic thickness of the Arabian plate: weak shield versus strong platform. Geophysical Research Letters, 42(9), 3298-3304.‏
Szymanski, E., Stockli, D. F., Johnson, P. R., & Hager, C. (2016). Thermochronometric evidence for diffuse extension and two‐phase rifting within the Central Arabian Margin of the Red Sea Rift. Tectonics, 35(12), 2863-2895.‏}

Contact: Taras Gerya or Attila Balazs, external advisor: Thamer Aldaajani
Project type: BSc or MSc
Major: Geophysics or Geology

The links between subduction dynamics and upper plate deformation

Oceanic and subsequent continental subduction and collision are fundamental elements in plate tectonics. The kinematics of subduction and associated mantle flow control the thermo-mechanical evolution of active margins. During progressive oceanic subduction the overriding plate can be affected by contraction or extension depending on the relative plate velocities. Surface topography is governed by the joint effects of crustal thinning or thickening via isostasy, stresses imposed at the base of the lithosphere controlled by asthenospheric flow and lithospheric flexure. Using existing 2D numerical simulations this project aims to quantify the spatial and temporal evolution of topography and surface heatflow at convergent margins at different scales. The role of rheological heterogeneities and different initial and boundary conditions will be analyzed in a series of numerical experiments. Understanding the rise and demise of forearc and backarc basins can provide conceptual insights into the interaction between subduction kinematics, mantle flow and sedimentary basin formation.

Contact: Attila Balazs, Taras Gerya
Project type: BSc or MSc
Major: Geophysics or Geology

Dynamic topography and sediment redistribution in extensional basins

Subsidence and uplift patterns and thermal history of sedimentary basins are controlled by a wide range of processes including tectonics, deep Earth dynamics, surface processes in terms of erosion, sediment transportation and deposition and their links to climatic variations. Crustal and lithospheric mantle thinning factors (βc, βlm) were usually derived from the analysis of syn- and post-rift sediment thicknesses to understand basin subsidence variations and its thermal evolution (e.g., Royden and Keen, 1980; Sclater et al., 1980). In contrast to these early kinematic models, many sedimentary basins show periods of anomalous subsidence and uplift pulses and associated thermal anomalies that do not fit the classical rift signatures. Forcing factors, such as increased intraplate stress, ductile flow of the lower crust, asthenospheric or deep mantle flow, variable erosion and sedimentation and the sensitive interplay between these processes should be considered. Using existing 2D numerical simulations this project aims to quantify the subsidence, burial and thermal evolution of sedimentary basins. A series of numerical experiments will be conducted to analyse the influence of mantle convection and its effects on the development of thermal and subsidence anomalies in extensional sedimentary basins.

Contact: Attila Balazs, Taras Gerya
Project type: BSc or MSc
Major: Geophysics or Geology

Discontinuity out of continuity

Volcanism is by definition discontinuous with volcanic eruptions and periods of magma injection (recorded by surface deformation; Fig. 1 inset; Biggs and Pritchard, 2017) being intercalated by repose intervals of different duration. Additionally, all well-studied volcanic provinces show that the average eruption rate is variable in the millions of year timescale (Fig. 1; de Silva and Kay, 2018; Salisbury et al., 2011). With this project we intend to assess if such variability is controlled by variations of the rate of magma supply from the mantle into the crust. More specifically numerical modelling will serve to constrain the rate of melt production and the rate of melt extraction from the mantle. If the rate of extraction is higher than the rate of melt production, this would intrinsically lead to a periodic behaviour with characteristic periodicity linked to subduction parameters. The findings of this study will help understanding if periods of enhanced volcanism are modulated by magma productivity in the mantle and help constraining the potential evolution of a volcanic region toward a period of enhanced volcanism.

REFERENCES
Biggs, J., Pritchard, M.E., 2017. Global Volcano Monitoring: What Does It Mean When Volcanoes Deform? Elements. doi:10.2113/gselements.12.3.xx
de Silva, S.L., Kay, S.M., 2018. Turning up the Heat: High-Flux Magmatism in the Central Andes. Elements 14, 245–250. doi:10.2138/gselements.14.4.245
Salisbury, M.J., Jicha, B.R., de Silva, S.L., Singer, B.S., 2011. 40Ar/39Ar chronostratigraphy of Altiplano-Puna volcanic complex ignimbrites reveals the development of a major magmatic province. Geol Soc Am Bull 123, 821–840. doi:10.1130/B30280.1

Contact: Taras Gerya and Luca Caricci ()
Project type: BSc/MSc
Major: Geophysics or Physics

Plate interaction in New Zealand using 3D numerical modelling

The southern island of New Zealand sits at the boundary of the Australian and Pacific plates. The relative plate motion is well constrained, but where exactly it takes place is still a mystery. Is it completely localized along the Alpine Fault, which is considered to be the "official" plate boundary? Or is it distributed within the plates themselves? How do the crust and lithospheric mantle behave in the proximity of the plates boundary? The project involves addressing these questions by setting, running, and analyzing numerical simulations using a 3D numerical model.

Contact: Taras Gerya, Sebastien Castelltort, Liran Goren
Project type: BSc or MSc
Major: Geophysics or Geology

Rifting, transforms and localized volcanism in young oceanic lithosphere

Using existing 3-D numerical models of oceanic spreading initiation compared to the natural data the Terceira ultra-slow rift in the Azores will be investigated. Main goal is to understand rift asymmetry and distribution of volcanic islands inside the rift.

Contact: Taras Gerya, Fernando Marques
Project type: BSc or MSc
Major: Geophysics or Geology

3-D dynamics of subduction and crustal growth in magmatic arcs

3-D numerical experiments simulating subduction of an oceanic plate under a continent will be performed with the use of existing numerical models. Variations in slab geometry, continental margin topography, magmatic arc productivity and back-arc extension will be studied as a function of various physical parameters.