http://messenger.jhuapl.edu/gallery/sciencePhotos/image.php?gallery_id=2&image_id=775 wrote: <<This image, taken with the Wide Angle Camera (WAC), provides a master class in Mercury surface features and the geologic processes that formed them. The image shows a portion of Rachmaninoff, a double-ring basin named for the early twentieth century Russian composer, pianist and conductor Sergei Rachmaninoff. In this region, we see the remnants of an inner peak ring, with hollows dusting the tops of the peaks in both the inner and outer rings. Also visible is the basin's main rim scarp beginning in the left corner of the image and extending to the southeast. The crater floor contains a number of regions of high-reflectance material, as well as polygonal valleys called graben (located near the top of the image, at the basin's center). Graben are formed by forces pulling apart the surface; these extensional forces are in contrast to the tectonic contraction we typically see all over Mercury and may be related to cooling of the smooth volcanic plains that cover the floor.
This image was acquired as a high-resolution targeted observation. Targeted observations are images of a small area on Mercury's surface at resolutions much higher than the 250-meter/pixel morphology base map or the 1-kilometer/pixel color base map. It is not possible to cover all of Mercury's surface at this high resolution during MESSENGER's one-year mission, but several areas of high scientific interest are generally imaged in this mode each week.>>
Rachmaninoff
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neufer
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Rachmaninoff
Art Neuendorffer