Mars
Most of my work on Mars has involved its evolution and interior. For instance, why did early Mars possess a dynamo, which later died? Possible answers are that there was an early episode of plate tectonics, or that Mars’ core started off very hot. I have also looked at the enigmatic fact that one half of Mars has a thicker crust than the other half – the hemispheric dichotomy. Together with Shawn Hart, one of my students, we showed that the dichotomy could have been formed when a massive asteroid hit Mars and stripped the crust off half the planet. The figure below shows a snapshot shortly after the impact, with crustal particles (orange) being flung off into space.
Snapshot of Mars shortly after being hit by an asteroid 600 km across (see the Nature article for more details;
also see this article written by UCSC undergrad Nathan Barth for his SCIC 160 term project).
More recently, I have become interested in the near-surface of Mars. For instance, the existence of near-surface ground ice is likely to cause modification to the local topography in ways which are both detectable and should allow us to infer some of the properties of this ice layer. Similarly, large impacts are likely to melt the ice and cause local hydrothermal systems.
I currently have two students working on Mars-related topics. Charlie Barnhart has just completed a study of Martian valley networks, and Reid Parsons looked at using Martian topography to infer how much ice there is in the near-surface.
Publications
Here is a list of recent Mars-related papers:
· North-south asymmetry in Martian crater slopes R.A. Parsons and F. Nimmo, J. Geophys. Res. 114 E02002, 2009 Reprint (PDF)
· Implications of an impact origin for the Martian hemispheric dichotomy, F. Nimmo, S.D. Hart, D.G. Korycansky, C.B. Agnor Nature 453 1220-1223, 2008, Reprint Supplementary Info.(PDF)
· The formation of Tharsis on Mars: What the line-of-sight gravity is telling us, J.-P. Williams, F. Nimmo, W.B. Moore, D.A. Paige, J. Geophys. Res. 113 , E10011, 2008. Reprint (PDF)
· How rapidly did Mars accrete? Uncertainties in the Hf-W timing of core formation, F. Nimmo and T. Kleine Icarus ,191, , 497-504, 2007. Preprint (PDF)
· Formation of methane on Mars by fluid-rock interaction in the crust , J.R. Lyons, C. Manning and F. Nimmo, Geophys. Res. Lett., 32 , L13201, 2005. Reprint (PDF) Auxiliary Material (PDF)
· Tectonic consequences of Martian dichotomy modification by lower crustal flow and erosion F. Nimmo, Geology , 33, 533-5361, 2005.Reprint (PDF)
· Early crustal evolution of Mars F. Nimmo and K. Tanaka, Ann. Rev. Earth Planet. Sci. , 33, 133-161, 2005. Reprint (PDF)
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Last Modified:18th Oct 2009.