2015 GSA Annual Meeting in Baltimore, Maryland, USA (1-4 November 2015)

Paper No. 340-8
Presentation Time: 3:40 PM


MARTIN, Emily S.1, MCDANIEL, Jessica2 and WATTERS, Thomas R.1, (1)Center for Earth and Planetary Studies, National Air and Space Museum, Smithsonian Institution, Washington, DC 20560, (2)Department of Geosciences, University of Massachusetts Amherst, Amherst, MA 01003, martines@si.edu

Dione’s wispy terrains, centered on the icy moon’s leading hemisphere, are some of the most heavily tectonized terrains in the Saturnian system. However, Dione lacks the hemispherical symmetry seen on Enceladus’s leading and trailing hemisphere tectonized terrains. To date, no detailed fracture mapping of these regions have been completed in conjunction with a detailed characterization of the tectonic structures which comprise the wispy terrains. With this work, we produced detailed fracture maps of the wispy terrains as well as a morphological classification of the structures. Characterization of these structures shows a dearth of diverse structures identified as scarps, twin scarps (likely graben), and troughs. Two additional types of features are classified, but may not be tectonic. While not as heavily tectonically resurfaced as Enceladus, it interesting that Dione’s tectonic structures are so limited in morphology where Enceladus’s surface shows a wide diversity of tectonic structures. Jupiter’s moon Europa is expected to host a global subsurface ocean, similarly hypothesized for Enceladus, the presence of which suggests that nonsynchronous rotation may be occurring, or has occurred in the past. Thus if fracture patterns on Dione are similar to what is predicted due to nonsynchronous rotation, it would suggest that Dione has or had a global subsurface ocean. Using SatStressGUI, we model stresses on Dione’s surface due to nonsynchronous rotation and compared the predicted fracture orientations with the distribution of mapped fractures. We find a good first-order match between observed fracture orientation and the orientation of those predicted by SatStressGUI; however, further analysis is required.