Ref: SCART-2020-0126

The environmental effects of very large bolide impacts on early Mars explored with a hierarchy of numerical models

Gillmann, Cedric ; Forget, Francois ; Baudin, Baptiste ; Palumbo, Ashley ; Head, James ; Karatekin, Ozgur

published in Icarus, 335 (2019)

Abstract: The origin of the presence of geological and mineralogical evidence that liquid water flowed on the surface of early Mars is now a 50-year-old mystery. It has been proposed (Segura et al., 2002, 2008, 2012) that bolide impacts could have triggered a long-term climate change, producing precipitation and runoff that may have altered the surface of Mars in a way that could explain (at least part of) this evidence. Here we use a hierarchy of numerical models (a 3-D Global Climate Model, a 1-D radiative-convective model and a 2-D Mantle Dynamics model) to test that hypothesis and more generally explore the environmental effects of very large bolide impacts (Dimpactor > 100 km, or Dcrater > 600 km) on the atmosphere, surface and interior of early Mars. Using a combination of 1-D and 3-D climate simulations, we show that the environmental effects of the largest impact events recorded on Mars are characterized by: (i) a short impact-induced warm period (several tens of Earth years for the surface and atmosphere to be back to ambient conditions after very large impact events); (ii) a low amount of hydrological cycling of water (because the evaporation of precipitation that reached the ground is extremely limited). The total cumulative amount of precipitation (rainfall) can be reasonably well approximated by the initial post-impact atmospheric reservoir of water vapour (coming from the impactor, the impacted terrain and from the sublimation of permanent ice reservoirs heated by the hot ejecta layer); (iii) deluge-style precipitation (∼2.6 m Global Equivalent Layer of surface precipitation per Earth year for our reference simulation, quantitatively in agreement with previous 1-D cloud free climate calculations of Segura et al., 2002), and (iv) precipitation patterns that are uncorrelated with the observed regions of valley networks.

DOI: 10.1016/j.icarus.2019.113419

The record appears in these collections:
Royal Observatory of Belgium > Reference Systems & Planetology
Science Articles > Peer Reviewed Articles

 Record created 2020-06-16, last modified 2020-06-16

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