We have identified a further example of mass movement, in addition to the previously identified example in the pyroclastic vent NE of Rachmaninoff. Both examples show evidence of hollow sublimation being a cause of the mass movements

Balme, M. R.

Conway, S. J.

Malliband, C. C.

Rothery, D. A.

English

International audienceWe have identified further example of mass movement, in addition to the previously identified example in the pyroclastic vent NE of Rachmaninoff (vent in Nathair Facula). These examples show evidence of hollow sublimation being a trigger of the mass movements

Malliband, Christopher C.

Conway, Susan J.

Rothery, David A.

Balme, Matthew R.

HAL-Univ-Nantes

Potential Identification of Sublimation-Driven Downslope Mass Movements on Mercury

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Open Research Online (The Open University)

Open Research OnlineThe Open University’s repository of research publicationsand other research outputsPotential Identification of sublimation-drivendownslope mass movement on MercuryConference or Workshop ItemHow to cite:Malliband, C. C.; Conway, S. J.; Rothery, D. A. and Balme, M. R. (2018). Potential Identification of sublimation-drivendownslope mass movement on Mercury. In: Mercury: Current and Future Science of the Innermost Planet, 1-3 May2018, Columbia, Maryland, USA.For guidance on citations see FAQs.c© [not recorded]Version: Version of RecordCopyright and Moral Rights for the articles on this site are retained by the individual authors and/or other copyrightowners. For more information on Open Research Online’s data policy on reuse of materials please consult the policiespage.oro.open.ac.ukPOTENTIAL IDENTIFICATION OF SUBLIMATION-DRIVEN DOWNSLOPE MASS MOVEMENT ON MERCURY.  C.C. Malliband1, S.J. Conway*2, D.A. Rothery1, and M.R. Balme1, 1School of Physical Sciences, The Open University, Milton Keynes, MK7 6AA, UK (chris.malliband@open.ac.uk), 2CNRS, LPG, Université de Nantes, France (susan.conway@univ-nantes.fr) *presenting author  Introduction:  Mass movement has been recog-nised on many solar system bodies. Evidence of mass movement on Mercury has previously been limited to a single documented example, found in the pyroclastic vent NE of Rachmaninoff crater. Here we present the identification of a second example in a small, recent impact crater, ≈285 km north of Nabokov. Mass movement at NE Rachmaninoff Vent: At-tention was drawn to the slope features in the NE Rachmaninoff vent (Fig. 1) on the MESSENGER web-site, but so far as we are  aware there has been no for-mal study. The features are downslope erosion-deposition systems with an alcove at the head, chute and a fan at the base. Feature heads appear to develop in a stratigraphic layer of brighter material (Fig. 1B). This brighter material appears to be related to hollows [1].  Slope features in unnamed crater (≈285 km N of Nabokov): The newly identified slope features are in a ≈12 km diameter simple impact crater. The crater is surrounded by low reflectance material and has an area of hollows on the NE crater rim. The slope features start just below the crater rim, in a bright stratigraphic layer. This may be similar to the hollow forming layer in NE Rachmaninoff.   Current work: We are examining other areas with steep slopes and catalogued hollows, and are perform-ing a global survey to identify any further examples. We will compare the topography of these features to erosion-deposition systems on Mars [2,3] and Vesta [4]. Our working hypothesis is that these downslope movements are caused by sublimation. References: [1] Blewett D.T. et al. (2011) Science,  333, 1856–1859. [2] Conway S.J. et al. (2015) Icarus,  253, 189–204. [3] Brusnikin E.S. et al. (2016) Icarus,  278, 52–61. [4] Scully J.E.C. et al. (2015) EPSL,  411, 151–163.  Acknowledgements: This work is partially sup-ported by the CNES, in preparation for BepiColombo.  Fig. 1: A,B,C Gully-like slope features in vent NE of Rachmaninoff. A:Context image centered on 36°N, 63.8°E showing widespread slope features. Box shows location of B. (NAC: EN1003843866M) B: High resolution (6.4m/pixel) image show-ing source at bright layer (NAC: EN1028933034M) C: Enhanced color. D, E, F. Newly discovered slope features at 8°S, 55°E. D, enhanced color; E, high incidence angle (NAC: EN0252295266M) F, low incidence angle. Note bright, possibly hollow forming, material, high in crater wall (NAC: EN1028933034M). 