Convection in a volatile nitrogen-ice-rich layer drives Pluto's geological vigour.
William B McKinnon1, Francis Nimmo2, Teresa Wong1
1Department of Earth and Planetary Sciences and McDonnell Center for the Space Sciences, Washington University in St Louis, Saint Louis, Missouri 63130, USA.
Nature
|June 3, 2016
View abstract on PubMed
Summary
Pluto's Sputnik Planum exhibits geological activity due to solid-state convection in its nitrogen ice layer. This process, driven by heat flow, shapes the icy surface and may occur on other dwarf planets.
Area of Science:
- Planetary Science
- Geophysics
- Glaciology
Background:
- Sputnik Planum on Pluto is a large basin filled with volatile ices, primarily nitrogen.
- The basin's surface is organized into convection cells, suggesting internal geological activity.
Purpose of the Study:
- To investigate the potential for solid-state convection in Sputnik Planum's nitrogen ice layer.
- To explain the observed scale of convection cells on Pluto's surface.
Main Methods:
- Analysis of available rheological measurements for nitrogen ice.
- Numerical modeling of convective overturn in a multi-kilometer-thick nitrogen ice layer.
Main Results:
- Nitrogen ice layers thicker than approximately one kilometer are predicted to convect under current heat-flow conditions on Pluto.
- Numerical simulations indicate that convective overturn can explain the large lateral width of Sputnik Planum's surface cells.
- The ice layer convects in a 'sluggish lid' regime, a mode not definitively observed elsewhere in the Solar System.
Conclusions:
- Solid-state convection is a likely driver of geological activity in Sputnik Planum.
- Surface renewal processes on Pluto occur on timescales shorter than the estimated age of the surface.
- Similar convective processes may explain the high albedos of other Kuiper Belt dwarf planets.
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