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Scours and Scarps
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Scours and Scarps

January 13, 2014
Release Date: January 13, 2014 Topics: NAC, Rembrandt, Scarps, Tectonics Date acquired: November 5, 2013 Image Mission Elapsed Time (MET): 25999800 Image ID: 5142079 Instrument: Narrow Angle Camera (NAC) of the Mercury Dual Imaging System (MDIS) Center Latitude: -20.99° Center Longitude: 100.55° E Resolution: 115 meters/pixel Scale: The field of view in this image is about 120 km (75 mi.) across Incidence Angle: 79.4° Emission Angle: 12.2° Phase Angle: 67.2° North is to the bottom of the image. Of Interest: The Rembrandt basin is the second-largest well preserved impact structure on Mercury, and is one of the best examples of a process that has irrevocably shaped the surface of the innermost planet. Yet the planet has been fundamentally shaped by another process—global contraction—that has resulted in the formation of lobate scarps and wrinkle ridges across the surface of Mercury. In this image, we see a good example of where these processes meet. The most prominent landform in the scene is a north–west-trending scarp, its eastern margin illuminated by the Sun. Scarps such as this form when one portion of Mercury's crust thrusts up over another, the result of crustal shortening in response to the planet's volume decreasing as its interior cools. Yet if you look carefully, you might spy an alignment in the texture of the surface here, trending from the bottom-left to the top-right of the image. This alignment is due to radial scouring of the surface around Rembrandt by debris thrown out during the impact that formed the basin. 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 200-meter/pixel morphology base map. It is not possible to cover all of Mercury's surface at this high resolution, but typically several areas of high scientific interest are imaged in this mode each week. The MESSENGER spacecraft is the first ever to orbit the planet Mercury, and the spacecraft's seven scientific instruments and radio science investigation are unraveling the history and evolution of the Solar System's innermost planet. During the first two years of orbital operations, MESSENGER acquired over 150,000 images and extensive other data sets. MESSENGER is capable of continuing orbital operations until early 2015. Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington