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

Coronae (latin for “crowns”) are large, quasi-circular volcano-tectonic structures abundant on the Venusian surface, characterized by a (partial) concentric annulus of closely spaced fractures. They likely bear testimony of turbulent interior processes:

An updated database of coronae on Venus

A new systematic analysis of the Venus surface reveals at least 736 coronae on Venus, significantly more than previously documented! We are developing an extensive database that will soon be ready for the public to use and augment. 

Paper submitted

Evidence for ongoing plume activity on Venus

Assuming coronae are formed by hot thermal upwellings, we use 3D computer models of plume-lithosphere interactions on Venus to assess their origin.  We find that corona morphologies not only represent different tectonic styles, but also different evolution stages. We suggest that topography can distinguish active from inactive coronae, and reveal widespread and ongoing plume activity on the planet. The global distribution of this geological activity raises intriguing questions on Venusian deep interior circulation and dynamics.

Published in our 2020 Nature Geoscience paper; lay article: 2021 The Science Breaker paper

Prolonged magmatic activity and eclogite recycling at asymmetric coronae

We analyze the topographic (a)symmetry and regional tectonic settings of the 155 largest coronae on Venus. Most are radially asymmetric and 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

Diverse tectonic processes at Venus’ coronae revealed by gravity and topography

We leverage 3D geodynamic models to predict free-air and Bouguer gravity signals under different corona tectonic scenarios. Among 75 coronae considered resolved by the current Venus gravity dataset, gravity indicates buoyant mantle material beneath 52. Fitting observations to models reveals a spectrum of plume-lithosphere interactions and activity stages across these coronae, providing insights beyond previous analyses. Finally, we predict that the gravity dataset from the upcoming VERITAS mission will resolve 425 coronae, and identify sites of interest for upcoming missions. 

Paper submitted

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. 

Diverse origins of lower mantle positive wave speed anomalies

Positive wave speed anomalies in the mantle often align with expected subducted slab locations, a correlation widely used in plate reconstructions and geodynamic modeling. However, global travel-time tomography is highly dependent on source-receiver geometry. We demonstrate that global full-waveform inversion is less sensitive to this geometry and uncovers many previously undetected anomalies in the lower mantle. These anomalies, often beneath major oceans and continental interiors without a subduction history, show no significant correlation with past subduction.

Paper under review

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 

Compositional heterogeneity in Earth's lower mantle

We address the nature of chemical lower-mantle heterogeneity, how it has evolved, and how it has affected our planet’s evolution. We do so by the integration of numerical models of long-term mantle convection with interdisciplinary observations of the deep Earth.

Coupled dynamics of primordial and recycled heterogeneity in Earth's lower mantle

We investigate the coupled dynamics and evolution of primordial domains and recycled materials in Earth’s mantle. 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. Here, We explore the effects of composition-dependent rheology on heterogeneity preservation and the styles of mantle convection. Several regimes of primordial material preservation can occur in terrestrial planets, some of which are here characterised for the first time and highly relevant to the Earth.

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