The interactions and feedbacks between surface processes and plate tectonics
My current research focus is on the interplay between deep and surface processes in plate tectonics. I aim to understand the interactions and feedbacks between surface processes (erosion/sedimentation, weathering, climate) and plate tectonics. In particular, I am testing the hypothesis that surface processes largely controlled the emergence and evolution of plate tectonics (Sobolev and Brown, 2019) using modeling, existing and new geochemical data. This project is part of the prestigious ERC Synergy grant MEET: http://www.geology.wisc.edu/~wiscsims/ERC/MEET/
I also study deeper processes which occur in the Earth:
- Anisotropy and melt from plume-lithosphere interactions
In this study we investigate anisotropic signatures at lithosphere asthenosphere boundary depths from: i. purely flow-induced asthenospheric anisotropy ii. a plume-lithosphere interaction and iii. partial melt or layering at the base of the lithosphere. We find that a slight depth-age dependency of radial anisotropy is simply the result of shearing in the asthenosphere. We find that unstable flow lines from plume-lithosphere interactions generate isotropy. Partial melt from the plume lithosphere interaction can generate substantial anisotropy (~1.1) via SPO at 120-150 km depth beneath Hawaii. We propose that anisotropy from melt plays a key role in flattening the lithosphere-asthenosphere boundary as seen by tomography models.
**Kendall, E., Faccenda, M. and Ferreira, A.M.G. (2021) Anisotropy and melt from plume-lithosphere interactions beneath the Pacific. In prep for Earth and Planetary Science Letters.
- The dependence of seismic anisotropy on plate speed
We find that the strength and depth extent of radial anisotropy increases with increasing plate speed. Simple 2D ridge flow models combined with mantle fabric calculations show that these observations can be explained to first order by the lattice-preferred orientation of anisotropic minerals such as olivine. A less viscous rheology is required beneath fast plates to fit the observations, which could be the result of larger amounts of melt and/or pre-existing anisotropy.
**Kendall, E., Faccenda, M., Ferreira, A.M.G., Chang., S-J., (2021) The dependence of seismic anisotropy on plate speed. In prep for GRL.
- Upper mantle seismic structure of the Pacific from waveform modelling
I focus on radial anisotropy (the difference between horizontally polarized and vertically polarized shear waves), which can be a key probe of the geometry of mantle flow. We assess radially anisotropic features in 3D tomographic models with full waveform modelling along with independent data. The data require an asymmetry in radial anisotropy at the East Pacific Rise possibly linked to flow beneath the South Pacific Superswell. Our new radial anisotropy constraints show a lateral age-dependence, which possibly reflects a change in flow from the horizontal direction.
**Kendall, E., Ferreira, A. M. G., Chang, S.-J., Witek, M., & Peter, D. (2021). Constraints on the upper mantle structure beneath the Pacific from 3-D anisotropic waveform modeling. Journal of Geophysical Research: Solid Earth, 126, e2020JB020003. https://doi.org/10.1029/2020JB020003
- The evolution of mantle plumes beneath East Africa
Here we assemble geochemical and seismological constraints along with information from new seismic analyses and geodynamic laboratory experiments to propose that presently there are at least two different plume heads beneath Afar and Kenya that originated at the CMB. A third plume between Kenya and Afar may have caused the Ethiopia-Yemen traps 30 Ma, now merging with the Afar plume. We infer that the Afar plume is presently detached from the CMB probably because of an interaction with the subducted Tethyan slab and that it is likely a dying plume. This may imply that rifts along the Main Ethiopian Rift would fail by the loss of thermal sources, which consequently hampers continental breakup.
**Chang, S.‐J., Kendall, E., Davaille, A., & Ferreira, A. M. G. (2020). The evolution of mantle plumes in East Africa. Journal of Geophysical Research: Solid Earth, 125, e2020JB019929. https://doi.org/10.1029/2020JB019929
- Indian Ocean Geoid Low at a plume-slab overpass
One of the most pronounced geoid lows on Earth lies in the Indian Ocean just south of the Indian peninsula. Here we propose that the IOGL can be explained due to a linear, approximately north-south-trending high-density anomaly in the lower mantle, which is crossed by a linear, approximately West-Southwest-East-Northeast trending anomaly low-density anomaly in the upper mantle. While the former can be explained due to its location in a region of former subduction and inbetween the two Large Low Shear Velocity Provinces (LLSVPs), we propose here that the latter is due to an eastward outflow from the Kenya plume rising above the eastern edge of the African LLSVP.
**Steinberger, B., Rathnayake, S., Kendall, E., (2021). The Indian Ocean Geoid Low at a plume-slab overpass. Tectonophysics, 817. https://doi.org/10.1016/j.tecto.2021.229037
- Anisotropy across the North Anatolia Fault
**Cornwell, D.G., Rost, S., Thompson, Houseman, G.A., Millar, L.A., Kendall, E.,..(2021). Variations in lithospheric anisotropy across the North Anatolian Fault revealed by teleseismic shear wave splitting (in review at GRL).
2020-present: Research Associate (GFZ)
2019-2020: Fellow (University College London)
2016-2019: PhD in Computational Geophysics, University College London
Supervisors: Ana Ferreira, Manuele Faccenda
2014-2015: MSc Geophysics, University College London
Supervisor: Carolina Lithgow-Bertelloni
2011-2014: BSc in Physics, University of Warwick
Postdoc in the ERC Synergy Project MEET http://www.geology.wisc.edu/~wiscsims/ERC/MEET/
2021: Computational time (1212kNPL) on HLRN (Northern German Computing Alliance) for GFZ geodynamic modelling section
2019: CINECA, Italy Padova Computational time: 100,000 core hours
2019:Short-term Scientific mission (STSM) grant €900
2018:Royal Astronomical Grant £443 to present PhD results at European Geosciences Union