GSA Annual Meeting in Denver, Colorado, USA - 2016

Paper No. 211-2
Presentation Time: 1:55 PM


HOWARD, Alan D.1, MOORE, Jeffrey M.2, MCKINNON, William B.3, SPENCER, John R.4, SCHENK, Paul M.5, BEYER, Ross6, NIMMO, Francis7, WHITE, Oliver Luke8, SINGER, Kelsi N.9, UMURHAN, Orkan10, STERN, S. Alan11, ENNICO, Kimberly2, OLKIN, Cathy4, WEAVER, Harold A.12, YOUNG, Leslie A.11, GRUNDY, William M.13 and TEAM, New Horizons Science4, (1)Department of Environmental Sciences, Univerisity of Virginia, PO Box 400123, Charlottesville, VA 22904-4123, (2)NASA Ames Research Center, Space Science Division, MS-245-3, Moffett Field, CA 95129, (3)Washington University, Department of Earth and Planetary Sciences and McDonnell Center for the Space Sciences, One Brookings Drive, Saint Louis, MO 63130, (4)Southwest Research Institute, Boulder, CO 80302, (5)Lunar and Planetary Institute, Houston, TX, (6)NASA, Ames Research Center, Moffet Field, CA 94035, (7)Department of Earth and Planetary Sciences, University of California Santa Cruz, 1156 High Street, Santa Cruz, CA 95064, (8)NASA, Ames Research Center, MS 245-3, Moffett Field, CA 94035-1000, (9)Southwest Research Institute, 1050 Walnut St #300, Boulder, CO 80302, (10)NASA Ames Research Center, Space Science Division, MS-245-3, Moffett Field, CA 94035, (11)Southwest Research Institute, 1050 Walnut Street, Boulder, CO 80302, (12)Applied Physics Laboratory, Johns Hopkins University, Laurel, MD 20723, (13)Lowell Observatory, 1400 W. Mars Hill Rd., Flagstaff, AZ 86001,

The New Horizons mission has revealed surprisingly diverse geologic settings on Pluto and Charon. Although abundant craters indicate that the Pluto system formed early in Solar System history, the surface of Pluto is volatile rich, featuring the 1000x1500 km Sputink Planum basin dominated by thick Nitrogen-rich ices with modern N2 glacial flow, convective cell patterning, sublimation pitting, prominent chaotic water ice mountains, and a geologically-recent surface age. Uplands on the encounter hemisphere feature methane-rich mantles, deep pitting, and valleys probably carved by paleoglaciers, as well as extensional faults. Parts of the equatorial belt are mantled with dark tholins.

Charon, like Pluto, is differentiated with a water ice crust, but lacks abundant surface volatiles. A prominent ~250 km-wide belt of extensional faulting dominates the encounter hemisphere. The eastern border of the encounter hemisphere features prominent peaks extending about 3-5 km above the floors of surrounding moats, and the moats lie 1-2 km above surrounding plains. Charon also displays a variety of basins, extensional faults and probable cryovolcanic-resurfaced plains. Charon features a prominent reddish north polar cap that may be tholins sourced from atmospheric escape from Pluto and delivery to Charon.

Charon and Pluto probably have a collisional origin, and freeing of a subsurface water ocean has caused the dominantly extensional tectonism.