My research interests include the long-term evolution of rocky planets, how interior processes link to a planet’s surface tectonics and volcanism, and, ultimately, to the planet’s (in)habitability. I aim at putting space, geophysical, geological, and cosmo-/geochemical observations in a physics-based framework using numerical modelling techniques. You can find more details on my research projects below.
Towards a recipe for the deep Earth
The lower mantle is the largest geochemical reservoir in the Earth’s interior. It controls the style of mantle convection and, through it, the long-term evolution of our planet. Constraining the composition and structure of Earth’s lower mantle, however, remains a scientific challenge that requires cross-disciplinary efforts. During my PhD, I have searched for the chemical and rheological recipe of Earth’s lower mantle through numerical models of long-term mantle convection and integration with interdisciplinary observations of the deep Earth.
Geodynamic consequences of strain-weakening rheology in the lower mantle: narrow, cold, and "cool" mantle plumes
Earth’s lower mantle’s main constituents are the strong mineral Bridgmanite (~80%) and the weaker Ferropericlase (~20%). The viscosity of such a multiphase rock depends on the modal abundance of weak versus strong minerals as well as the fabric of the rock. Using geodynamic models with a newly implemented strain-weakening (SW) rheology, we study the effect of strain-weakening rheology on global-scale mantle convection. We find that SW rheology particularly influences mantle flow patterns, thermochemical pile stability, and the features of mantle plumes. We ultimately propose that weakened plumes could explain the long-known discrepancy between expected and observed thermal anomalies of deep-seated mantle plumes on Earth.
Coupled dynamics of primordial and recycled heterogeneity in Earth's lower mantle
We address the nature of chemical lower-mantle heterogeneity, how it has evolved over time, and how it has affected our planet’s evolution. I investigate the coupled dynamics and evolution of primordial domains and recycled materials in numerical models of mantle convection. Primordial and recycled materials are robustly predicted to co-exist with each other. This study provides a new integration of independent hypotheses of present-day lower-mantle heterogeneity, which we link to geochemical and geophysical observations.
We further present the first 3D spherical shell mantle convection models that explicitly address the evolution of multiple types of mantle heterogeneity (i.e., intrinsically-dense, recycled and intrinsically-strong, primordial materials) in Earth-like planets, and describe mixing behaviour and geometries of recycled and primordial mantle reservoirs in the 3D mantle. The work provides an important step towards integrating recent theories of Earth’s mantle structure into a more realistic framework.
Paper in preparation
Dynamic styles of primordial material preservation in Earth's interior
Cosmo- and geochemical constraints indicate that Earth’s lower mantle hosts an ancient primordial reservoir enriched in silica with respect to the upper mantle. Yet, geophysical observations and models point to efficient convective mixing across the entire mantle. Here, I explore the effects of composition-dependent rheology on heterogeneity preservation and the styles of mantle mixing. Several regimes of primordial material preservation can occur in terrestrial planets, some of which are here characterised for the first time and can reconcile the preservation of primordial domains in Earth’s convecting mantle.
The geodynamic and tectonic puzzle of Venus
Our neighbouring planet Venus presents a clear contrast of tectonics with the Earth, despite similar interior structure and composition. Even in the absence of plate tectonics, Venus’ surface is littered with volcanic structures, rifts, and mountains. To what extent these surface features reflect the current state of the planet’s interior, remains in question. A better understanding of the dynamic interior processes at play, and how they link to the Venus’ surface, is key for our understanding of the geological evolution of rocky planets (such as Earth), and even their habitability.
Corona structures provide unique insights into the present-day geological activity of Venus
Corona structures are large ring-shaped volcano-tectonic that may bear testimony of turbulent interior processes of Venus:
I systematically ran 3D computer models of plume-lithosphere interactions on Venus to assess the origin of coronae and the reason behind their morphological differences. Corona morphologies not only represent different dynamic styles of plume-lithosphere interactions, but also different stages in evolution. Therefore, corona structures related to ongoing plume-lithosphere interaction may be distinguished from fossil corona structures. Guided by these outcomes, we systematically investigated the topographic patterns of large coronae on the Venusian surface. We identified which structures are currently active and which are currently inactive. This assessment revealed broad regions of ongoing plume activity on the planet, presenting new evidence for widespread recent magmatic activity on the surface of Venus. The global distribution of this proposed tectono-magmatic activity sparks intriguing questions on Venusian deep interior circulation and dynamics.
In nature, many Venusian coronae display more complex morphologies than those investigated in earlier numerical studies (see above). In this project, classify the 130 largest coronae on Venus in terms of surface morphology and their relation to the immediate surroundings. This reveals that the majority of coronae have asymmetrical features and are positioned at a topographic margin. With 3D numerical models, we investigate the physical processes behind plume-margin interactions on Venus,and make important conclusions about the physical processes responsible for Venus’ geology.
Paper in preparation
The peculiar case of rift zones on Venus
Detachment faults and intra-oceanic subduction initiation
Extensional detachment faults, widely documented in slow-spreading and ultraslow-spreading ridges on Earth, can effectively localise deformation due to their weakness. After the onset of oceanic closure, these weak faults may control the nucleation of a subduction zone parallel to the former mid-ocean ridge. We conducted a series of 3D numerical experiments to investigate the formation of detachment faults in slow oceanic spreading systems and their subsequent response upon inversion from spreading to convergence. We define the controlling parameters for detachment fault formation, and show how these faults affect the dynamics of intra-oceanic subduction initiation.