Impact basin relaxation as a probe for the thermal history of Pluto. Issue 10 (30th October 2014)

• Record Type: Journal Article
• Authors: Kamata, Shunichi; Nimmo, Francis
• Is Part Of: Journal of geophysical research. Volume 119:Issue 10(2014:Oct.)
• Page Start: 2272
• Page End: 2289
• Publication Date: 2014-10-30
• Subjects: Planets -- Periodicals; Geophysics -- Periodicals; 559.9
• DOI: 10.1002/2014JE004679
• Languages: English
• ISSNs: 2169-9097

Abstract

<abstract abstract-type="main" id="jgre20322-abs-0001"> <title>Abstract</title> <p id="jgre20322-para-0001">We investigate viscoelastic impact basin relaxation on Pluto for a variety of thermal evolution scenarios encompassing both convective and conductive ice shells. Basins smaller than 200 km in diameter do not relax appreciably, while relaxation fractions can be up to ∼60% for large impact basins. The main control on basin relaxation is the amount of radiogenic heat produced in the rocky core; our results are insensitive to the formation time of the basin, the ice reference viscosity adopted, and the presence/absence of a subsurface ocean. Other volatiles, such as CO₂ or NH₃, if present in the ice shell in sufficient quantities could increase the predicted relaxation fraction of basins. Relaxation causes extensional stresses interior to the basin; the orientation of the resulting tectonic features is controlled by the effective elastic thickness beneath the basin. Future observations of the relaxation states and tectonics of impact basins are therefore likely to provide a key constraint on Pluto's thermal history.</p> </abstract>