Research

My research interests include the long-term evolution of rocky planets and how interior processes are linked to a planet’s surface tectonics and volcanism. For the big picture, I’m keen to learn how these processes ultimately affect the planet’s (in)habitability. I strive to integrate observations from space, geophysics, geology, and geo/cosmo-chemistry into a physics-based framework using numerical modelling techniques. You can find more details on my research projects below. 

Venus: Earth's mysterious sister planet

Our neighbouring planet Venus presents a clear tectonic contrast to the Earth, despite similar interior structure and composition. Even in the absence of plate tectonics, Venus’ surface is covered with volcanic and tectonic structures both in familiar and exotic forms. To what extent these features reflect the current state of the planet’s interior remains uncertain. Understanding the dynamic interior processes at play and their link to Venus’ surface is key for our understanding of the evolution of rocky planets (such as Earth), and even their habitability.

Venus holds the key to Earth's past - or future?

Venus and Earth may have resembled each other in their earliest history. Yet, they took divergent evolution paths, leaving Earth and Venus with surface environments that could not be more different. Whereas Earth’s environment is habitable and allows for liquid water, Venus obtains a crushingly thick atmosphere over a hellish, hot surface. Understanding the dynamic mechanisms behind Venus’ geological history is a key objective in planetary sciences, as it helps to explain why Earth and Venus have diverged in towards their (in)habitable states.

Read more in our 2022, 2023, and 2024 Space Science Reviews papers in the Open Access collection ‘Venus: Evolution Through Time‘ 

Top: image from our 2023 review paper

The peculiar case of coronae on Venus

I am deeply interested in studying the enigmatic corona structures on Venus. Coronae (latin for “crowns”) are large, quasi-circular volcano-tectonic structures abundant on the Venusian surface, characterized by a (partial) fracture annulus. They bear testimony of turbulent interior processes (see below) and a key part of Venus’ global geodynamic regime. 

An updated database of coronae on Venus

Approximately 500 were identified after NASA’s Magellan mission (1989-1994). Yet, existing datasets are erroneous and incomplete. Our new systematic analysis reveals over 700 coronae on Venus, making the planet’s surface truly ‘coronated‘! We are developing an extensive database that will soon be ready for the public to use and augment. 

More coming soon!

Evidence for ongoing plume activity on Venus

I systematically ran 3D computer models of plume-lithosphere interactions on Venus to assess the origin and morphological differences of large coronae. Corona morphologies not only represent different styles of plume-lithosphere interactions, but also different evolution stages. I suggested that corona structures related to ongoing plume-lithosphere activity are distinguishable from fossil corona structures. Guided by these outcomes, I investigated the topography of large coronae, revealing widespread and ongoing plume activity on the planet. The global distribution of this tectono-magmatic activity raises intriguing questions on Venusian deep interior circulation and dynamics.

Published in our 2020 Nature Geoscience paper

Lay article published as 2021 The Science Breaker paper

Prolonged magmatic activity and eclogite recycling at asymmetric coronae

Our follow-up work combines mission data analysis with numerical modeling of asymmetric coronae on Venus. A database of the 155 largest coronae on Venus is provided, describing their topographic radial (a)symmetry and regional settings. Most large coronae are radially asymmetric and often located at a topographic transition between a lowland and plateau (‘margins’). We present the first 3D numerical models of plume-margin interactions on Venus, revealing various tectonic evolution scenarios. Interestingly, asymmetric coronae are generally longer-lived structures than symmetric ones. Additionally, we find that the basalt-to-eclogite phase change is crucial for the recycling of crustal material into the mantle.

Published in our 2023 Journal of Geophysical Research – Planets paper

Tectonic processes at Venus’ coronae revealed by gravity and topography

Using geodynamic models of Venus’ coronae mentioned above, we forward model the gravity signal of coronae under different formation scenarios and address the inverse problem of distinguishing between them through gravity and topography. We also assess the possibility of distinguishing tectonic activity vs. inactivity using the gravity field, and how future emission data may be able to reveal tectonic processes at large coronae on Venus. 

More coming soon!

Rift tectonics on Venus

One of the most prominent tectonic features on the Venusian surface is the presence of huge rift structures (“chasmata”). These rift systems can extend for thousands of kilometres and are present in numerous regions of the planet, but most dramatically throughout the Beta-Atla-Themis (BAT) region. Chasmata have similarities with some ultra-slow continental rifts and mid-ocean ridges on Earth. Yet, they also display unique features unlike terrestrial analogues, such as extreme dimensions, complex and discontinuous deformation patterns, and their association with numerous coronae. A key question of my research concerns how lithospheric extension accommodated within Venusian rift zones link to thermal plumes and intrusive magmatism. 

More coming soon!

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.

Strain-weakening rheology in the lower mantle: "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.

Published in our 2022 Geochemistry, Geophysics, Geosystems paper 

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.

Published in our 2021 Solid Earth paper

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. 

Published in our 2020 EPSL paper 

Earth's tectonics

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 geodynamical simulations 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 during mid-ocean ridge spreading, and then show how these faults affect the dynamics of intra-oceanic subduction initiation when the system is subjected to ridge-perpendicular compression. 

Published in our 2019 EPSL paper

Collaborators

  • Suzanne Smrekar (NASA Jet Propulsion Laboratory, USA)
  • Michael Gurnis (California Institute of Technology, USA)
  • Gael Cascioli (NASA Goddard Space Flight Centre, USA)
  • Erwan Mazarico (NASA Goddard Space Flight Centre, USA)
  • Quentin Brissaud (NORSAR, Norway)
  • Ellen Stofan (Smithsonian Institution)
  • Stephen Kane (UC Riverside, USA)
  • Ina-Catalina Plesa (DLR Berlin, Germany)
  • Julia Maia (DLR Berlin, Germany)
  • Iris van Zelst (DLR Berlin, Germany)
  • Richard Ghail (Royal Holloway University, UK)
  • Anna Horleston (University of Bristol, UK)
  • Maxim Ballmer (UCL London, UK)
  • Paul Tackley (ETH Zürich, Switzerland)
  • Cedric Gillmann (ETH Zürich, Switzerland)
  • Gregor Golabek (University of Bayreuth, Germany)
  • Marcel Thielmann (University of Bayreuth, Germany)
  • Taras Gerya (ETH Zürich, Switzerland)
  • Laurent Montési (Maryland University, USA)
  • Matteo Desiderio (UCL Earth Sciences, London, UK)

Feel free to contact me if you’d like to collaborate on an existing or new research project