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Relaxed impact craters on Ganymede: Regional variation and high heat flows

April 2, 2018

Viscously relaxed craters provide a window into the thermal history of Ganymede, a satellite with copious geologic signs of past high heat flows. Here we present measurements of relaxed craters in four regions for which suitable imaging exists: near Anshar Sulcus, Tiamat Sulcus, northern Marius Regio, and Ganymede's south pole. We describe a technique to measure apparent depth, or depth of the crater with respect to the surrounding terrain elevation. Measured relaxation states are compared with results from finite element modeling to constrain heat flow scenarios [see companion paper: Bland et al. (2017)]. The presence of numerous, substantially relaxed craters indicates high heat flows—in excess of 30–40 mW m−2 over 2 Gyr, with many small (<10 km in diameter) relaxed craters indicating even higher heat flows. Crater relaxation states are bimodal for some equatorial regions but not in the region studied near the south pole, which suggests regional variations in Ganymede's thermal history.

Publication Year 2018
Title Relaxed impact craters on Ganymede: Regional variation and high heat flows
DOI 10.1016/j.icarus.2018.01.012
Authors Kelsi N. Singer, Michael T. Bland, Paul M. Schenk, William B. McKinnon
Publication Type Article
Publication Subtype Journal Article
Series Title Icarus
Index ID 70196308
Record Source USGS Publications Warehouse
USGS Organization Astrogeology Science Center