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Athabasca Vallis Streamlined
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Athabasca Vallis Streamlined "Islands |
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Tremendous floods carved these tear drop-shaped landforms in Athabasca Vallis in the Cerberus region, south of the Elysium volcanoes. The orientation of the streamlined forms indicate that the fluid flowed from the right/upper right toward the left/lower left (from the northeast to the southwest). Similar features occur in central and eastern Washington in the northwestern United States. The examples in Washington formed when massive amounts of water rushed across the landscape, scouring a "channeled scabland" during the last Ice Age, roughly 12,000-13,000 years ago. The features on Mars are much older, while the absolute age cannot be determined, the small impact craters with rayed ejecta patterns on the flood surfaces indicate it must be much, much older than the flood landscape in Washington. This is a mosaic of six Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) images acquired in 1999 through 2002. Illumination is from the left. The mosaic covers an area 11.9 km (7.4 mi) by 13.0 km (8.1 mi). The full-size mosaic has a resolution of 4 meters (13 ft) per pixel. Images Credit: NASA/JPL/Malin Space Science Systems Caption by: K. S. Edgett and M. C. Malin, MSSS |
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Nirgal Vallis and its Windbl
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Nirgal Vallis and its Windblown Dunes |
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Nirgal Vallis is a narrow valley system that stretches approximately 420 kilometers (260 miles) across the martian surface near 28°S latitude, north of the large basin, Argyre. The floor of the valley system is largely covered with light-toned dunes and ripples. These windblown features obscure most of the original morphology of the valley floor. This view of a small portion of Nirgal Vallis was obtained by the Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) during Extended Mission subphase E02 on March 29, 2001. In each short tributary valley, dunes have a somewhat different orientation compared to those in the other valleys. The dune patterns here indicate that winds are locally controlled by the shape and orientation of each valley. The dunes just left of the center of the image have small craters on them, formed by meteor impact. The craters indicate that the dunes are not fresh, modern features, but are considerably older than they might at first seem. This image covers an area 3 km (1.9 mi) wide and is illuminated from the upper left. Image Credit: NASA/JPL/Malin Space Science Systems |
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Megaripples in Athabasca Val
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Megaripples in Athabasca Vallis |
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Researchers' goal in taking this image was to look for boulders in the large ripples formed by an ancient catastrophic flood in Mars' Athabasca Vallis. The Mars Orbiter Camera on NASA's Mars Global Surveyor spacecraft captured this image on Dec. 25, 2003, with use of an enhanced-resolution technique called compensated pitch and roll targeted observation. The flood-deposited megaripples had been seen in earlier, lower-resolution images from the same camera. They are the only good examples known of ripples formed in a giant catastrophic flood anywhere on Mars. Their presence indicates that large amounts of water poured rapidly through this area, based on resemblance to similar megaripples in catastrophic flood sites on Earth. The ripples in Athabasca Vallis were buried for some period and later exhumed. Strange, round features on top of some of the ripples and the adjacent plains are products of erosion and removal of the overlying layer. Finding boulders in the ripples would help constrain estimates of the power of the floods. However, the image does not show boulders in the ripples, implying either that the rocks that make up these features are smaller than about 1 to 2 meters (3 to 7 feet) in diameter or that the ripple sediments have not been completely exhumed. The image covers an area 3 kilometers (2 miles) wide, near 9.5 degrees north latitude and 203.7 degrees west longitude. Pixel size is about 1.5 meters (5 feet) by one-half meter (1.6 feet). North is up and sunlight illuminates the scene from the lower left. Photo Credit: NASA/JPL/Malin Space Science Systems |
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Nanedi Vallis
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Nanedi Vallis |
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This picture of a canyon on the Martian surface was obtained a few minutes after 10 PM PST, January 8, 1998 by the Mars Orbiter Camera (MOC), during the 87th orbit around Mars of the Mars Global Surveyor spacecraft. It shows the canyon of Nanedi Vallis, one of the Martian valley systems cutting through cratered plains in the Xanthe Terra region of Mars. The picture covers an area 9.8 km by 18.5 km (6.1 mi by 11.5 mi), and features as small as 12 m (39 ft) can be seen. The canyon is about 2.5 km (1.6 mi) wide. Rocky outcrops are found along the upper canyon walls, weathered debris is found on the lower canyon slopes and along the canyon floor. The origin of this canyon is enigmatic: some features, such as terraces within the canyon (as seen near the top of the frame) and the small 200 m (660 ft) wide channel (also seen near the top of the frame) suggest continual fluid flow and downcutting. Other features, such as the lack of a contributing pattern of smaller channels on the surface surrounding the canyon, box-headed tributaries, and the size and tightness of the apparent meanders (as seen, for example, in the Viking image 89A32), suggest formation by collapse. It is likely that both continual flow and collapse have been responsible for the canyon as it now appears. Further observations, especially in areas west of the present image, will be used to help separate the relative effects of these and other potential formation and modification processes. Malin Space Science Systems (MSSS) and the California Institute of Technology built the MOC using spare hardware from the Mars Observer mission. MSSS operates the camera from its facilities in San Diego, CA. The Jet Propulsion Laboratory's Mars Surveyor Operations Project operates the Mars Global Surveyor spacecraft with its industrial partner, Lockheed Martin Astronautics, from facilities in Pasadena, CA and Denver, CO. Photo Credit: NASA/JPL/Malin Space Science Systems |
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