EGU21-12082, updated on 04 Mar 2021
https://doi.org/10.5194/egusphere-egu21-12082
EGU General Assembly 2021
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.

Is Venus an analogue for Proterozoic Earth?

Richard Ghail
Richard Ghail
  • Royal Holloway University of London, Earth Sciences, Egham, United Kingdom of Great Britain – England, Scotland, Wales (richard.ghail@rhul.ac.uk)

Venus is our most Earth-like twin, from a geological standpoint, but lacks Earth-like plate tectonics. Its lower mean density implies a smaller core and relatively large mantle, which combined with the inhibited cooling effected by its high surface temperature, suggests that Venus today may be at an earlier evolutionary stage than Earth. Geologically, a global network of rifts and corona chains (e.g. Parga Chasma) indicate subsurface, plate tectonic-like, spreading ridges below a crustal detachment layer, but there are no obvious corresponding subduction zones. Subduction has been inferred locally at a few large corona (e.g. Artemis) but only in relation to specific plumes, not global plate tectonics. Elsewhere there is evidence for numerous large igneous provinces and perhaps an even larger Overturn Upwelling Zones (OUZO) event at Lada Terra. These features suggest a planet in transition from an Archaean-like regime dominated by instability and overturns, towards a more stable plate tectonic regime: i.e. a planet analogous to the early Proterozoic Earth.

How to cite: Ghail, R.: Is Venus an analogue for Proterozoic Earth?, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-12082, https://doi.org/10.5194/egusphere-egu21-12082, 2021.

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