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Layers Exposed In Crater Near Mawrth Vallis
Tempe AZ (SPX) Jul 19, 2007 This image covers an impact crater roughly 4 kilometers (2.5 miles) in diameter. The subimage shows just a small segment of the crater rim (1336 x 889; 3 MB). The surface outside the crater (top) is relatively dark, while the interior wall of the crater has a lighter tone. A few dark patches on the crater wall have small dunes or ripples on their surfaces, and are likely pits filled with dark sand. The light-toned material making up the crater wall is finely layered and fractured in places. The layers may be part of a sedimentary or volcanic ash deposit that became indurated (cemented and solidified) prior to the impact that formed the crater. The impact has revealed layers that were previously buried beneath the Martian surface, similar to the craters explored by the Opportunity rover in Meridiani Planum. These craters are windows into the Martian subsurface. Just 30 kilometers (20 miles) to the east of this crater lies Mawrth Vallis, an ancient outflow channel that may have been carved by catastrophic floods. The orbiting spectrometers OMEGA (on Mars Express) and CRISM (on MRO) have detected clay minerals in layered deposits in and around Mawrth Vallis. These minerals, which require water to form, are likely present in the layered bedrock exposed in this crater wall. The crater may thus provide a glimpse into an intriguing period of Martian history, when liquid water may have been more abundant at or near the Martian surface than it is today. Community Email This Article Comment On This Article Related Links Arizona's HiRISE site Mars News and Information at MarsDaily.com Lunar Dreams and more
Clay Studies Alter View Of Early Mars Environment
Fayetteville AR (SPX) Jul 19, 2007A study of the thermodynamics of clays found on Mars suggests that little carbon dioxide could have been present during their formation, which contradicts a popular theory of the early Martian atmosphere and will send researchers looking for other explanations for clay formation. Vincent Chevrier of the University of Arkansas and Francois Poulet and Jean-Pierre Bibring of the Universite Paris-Sud in Orsay, France, reported their findings in the journal Nature. |
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