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2009 Portland GSA Annual Meeting (18-21 October 2009)

Paper No. 4
Presentation Time: 3:15 PM

THE COLOR OF MERCURY


DENEVI, Brett W.1, ROBINSON, Mark S.2, SOLOMON, Sean C.3, MURCHIE, Scott L.4, BLEWETT, David T.4, DOMINGUE, Deborah L.4, MCCOY, Timothy J.5, ERNST, Carolyn M.4, HEAD, James W.6, WATTERS, Thomas R.7 and CHABOT, Nancy L.4, (1)Johns Hopkins University Applied Physics Lab, Laurel, MD, (2)School of Earth and Space Exploration, Arizona State University, Tempe, AZ 85251, (3)Department of Terrestrial Magnetism, Carnegie Institution of Washington, Washington, DC 20015, (4)Johns Hopkins University Applied Physics Laboratory, Laurel, MD 20723, (5)National Museum of Natural History, Smithsonian Institution, Washington, DC 20560, (6)Department of Earth, Environmental and Planetary Sciences, Brown University, Providence, RI 02912, (7)Center for Earth and Planetary Studies, National Air and Space Museum, Smithsonian Institution, Washington, DC 20560, N/A

Multispectral images from the MESSENGER spacecraft’s first two flybys of Mercury have revealed a planet rich in color and compositional diversity, with a dynamic past shaped by volcanism, deformation, and impact cratering. An examination of the key terrain types, as defined by both morphology and spectral properties, and their distribution across the surface provides new insights into the origin and evolution of Mercury’s crust.

Smooth plains cover ~40% of the mapped surface of Mercury, and many of these plains are likely of volcanic origin. Their spectral properties span nearly the full range seen across the planet, and smooth plains of intermediate reflectance are similar in color to older terrains such as the intercrater plains, suggesting a compositional similarity, and potentially a common origin. The featureless, red-sloped spectra of these terrains are consistent with a space-weathered surface in which the silicate fraction contains little FeO. Material low in reflectance and with a shallower spectral slope occurs in significant abundance over at least 15% of the surface and appears to be concentrated in impact crater and basin ejecta, suggesting an origin at depth. These deposits may represent cumulates that contain a higher fraction of spectrally neutral opaque minerals, such as Fe- and Ti-bearing oxides.

MESSENGER’s third and final flyby of Mercury before orbital insertion in 2011 will occur on 29 September 2009. Much of the terrain that will be observed is the same as that viewed during the second flyby, allowing a targeted look at the most intriguing features. Multispectral images, along with ultraviolet through near-infrared spectra, will be collected immediately after closest approach to allow for the highest resolution data of key spectral units, including low-reflectance material, high-reflectance and relatively red deposits likely of pyroclastic origin, and fresh crater rays. These new data will help to further our understanding of the composition, origin, and evolution of surface materials on Mercury.

Session No. 197

P4. First Global View of The Geology of Mercury: Dynamic Landscapes on The Innermost Planet
Tuesday, 20 October 2009: 1:30 PM-5:30 PM
Portland Ballroom 254 (Oregon Convention Center)
Geological Society of America Abstracts with Programs. Vol. 41, No. 7, p.509
© Copyright 2009 The Geological Society of America (GSA), all rights reserved. Permission is hereby granted to the author(s) of this abstract to reproduce and distribute it freely, for noncommercial purposes. Permission is hereby granted to any individual scientist to download a single copy of this electronic file and reproduce up to 20 paper copies for noncommercial purposes advancing science and education, including classroom use, providing all reproductions include the complete content shown here, including the author information. All other forms of reproduction and/or transmittal are prohibited without written permission from GSA Copyright Permissions.
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