The flyby of Pluto by the New Horizons spacecraft in 2015 revealed an unexpectedly diverse range of landscapes, implying a complex geological history. Dr. White has led the creation of a geologic map for the >75% of Pluto that was imaged. Pluto's wide range of surface ages appears to be primarily a consequence of how the distribution of volatile ices is affected by atmospheric, topographic, and obliquity effects. Large-scale geologic activity is ongoing in the form of convection and glacial flow of nitrogen ice in Sputnik Planitia, contained within a massive impact basin. There is a transition from volatile ice-poor, cratered, and ancient terrains west of Sputnik Planitia to younger accumulations of thick deposits of methane ice to its east, with the deposits being thicker and younger at the equator compared to the high latitudes. Pluto's oldest terrains are represented by smooth plains, thin, eroded mantling deposits, and glacially carved landscapes, and include the complex ridge-trough tectonic system that is aligned along a great circle. The configuration of these ancient landscapes may indicate that the ridge-trough system was aligned along Pluto's equator prior to true polar wander that occurred in response to the Sputnik impact. Relatively recent, large-scale endogenic activity may be represented by the tentatively cryovolcanic Wright and Piccard Montes.
Bio
Dr. White has been a Research Scientist at the SETI Institute (although resident at NASA Ames Research Center) since 2017. He gained his PhD in Planetary Science at University College London in 2010, followed by postdoctoral positions at the Lunar and Planetary Institute in Houston (2010-2010) and NASA Ames (2014-2017). His research has focused on a range of topics relating to the topographic characterization and geologic evolution of planetary landscapes, primarily in the outer solar system. He has produced topographic maps of Io and the Saturnian mid-sized icy satellites, and used landform evolution modeling to investigate the formation and evolution of Callisto’s ice pinnacle terrain and Titan's karst-like steep-edged depressions in its polar regions. He is an emeritus Co-I on the New Horizons mission and has produced a global geologic map of Pluto to be published by the USGS in 2025, and is creating a similar USGS map of Saturn's moon Tethys.
Venue
Seminar room 1
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