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 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 evolution of rocky planets (such as Earth), and even their habitability.

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

Venus and Earth perhaps resembled each other in their earliest history. Yet, they set off on very different evolutionary 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 responsible for Venus’ geological history is a key objective in terrestrial planetary sciences, as it helps to answer why Earth and Venus have undergone such staggeringly divergent evolutionary paths towards their (in)habitable states.

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

Top: image from our 2023 review paper

An updated database of Venusian coronae

Corona structures are large ring-shaped volcano-tectonic structures abundant on the Venusian surface. They bear testimony of turbulent interior processes (see below). Around 500 had been identified in the post-Magellan era, although to-date, only 347 coronae were officially named through the US Geological Survey (USGS) planetary nomenclature process. All available datasets are in fact erronous and incomplete. Our new systematic analysis reveals well over 700 coronae on Venus, making the planet’s surface truly ‘coronated‘! We are working on an extensive database soon ready for the public to use and augment. 

More coming soon!

Volcano-tectonic "corona" structures provide unique insights into the geological activity of Venus

I systematically ran 3D computer models of plume-lithosphere interactions on Venus to assess the origin of large coronae on Venus 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. I found that corona structures related to ongoing plume-lithosphere activity are distinguishable from fossil corona structures. Guided by these outcomes, I systematically investigated the topography of large coronae using Venus mission data. 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.

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

In nature, many Venusian coronae display more complex morphologies than those investigated in earlier numerical studies (see above).  Our follow-up work presents a joint study of mission data analysis and numerical modelling of asymmetric coronae on Venus. I provide a database of the 155 largest coronae on Venus describing their topographic radial (a)symmetry and regional setting. Most large coronae are radially asymmetric, and many are positioned at a topographic transition between a lowland and plateau (‘margin’). We then present the first 3D numerical models of plume-margin interactions on Venus. We find several different types of tectonic evolution scenarios. Interestingly, we find that asymmetric coronae are generally longer-lived structures than symmetric coronae. Moreover, we find that the basalt-to-eclogite phase change is key in crustal material recycling into the mantle. This work aids our understanding of the interior processes responsible for Venus’ geology.

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!

The peculiar case of 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.

Geodynamic and tectonic consequences of strain-weakening rheology in the lower mantle: narrow, "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

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. 

Published in our 2020 EPSL paper 

Intra-oceanic subduction initiation on Earth

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 Lab, USA)
  • Gael Cascioli (NASA Goddard Space Flight Centre)
  • Mike Gurnis (California Institute of California)
  • Ellen Stofan (Smithsonian Museum, Washington DC)
  • Stephen Kane (UC Riverside, USA)
  • Maxim Ballmer (UCL Earth Sciences, Londen)
  • Paul Tackley (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