| Nili Fossae | |
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Nili Fossae as seen by CRISM. Top left: location of observation. Bottom left: context of observation. Top right: yellow-brown areas denote olivine, bright green areas denote phyllosilicates and purple areas pyroxene. Bottom right: approximate true color view of the target area. |
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| Length | 667.0 |
Nili Fossae is a fracture in the surface of Mars that has been eroded and partly filled in by sediments and clay-rich ejecta from a nearby crater. It is located at approximately 22°N, 75°E, and has an elevation of −0.6 km (−0.37 mi). Nili Fossae was on the list of potential landing sites of the Mars Science Laboratory, arriving in 2012, but was dropped before the final four sites were determined.
A large exposure of olivine is located in Nili Fossae. In December 2008, NASA's Mars Reconnaissance Orbiter found that rocks at Nili Fossae contain carbonate minerals, a geologically significant discovery.[1] Other minerals found by MRO are aluminum smectite, iron/magnesium smecite, hydrated silica, kaolinite group minerals, and iron oxides. [2] NASA scientists discovered that Nili Fossae is the source of plumes of methane, raising the question of whether this source originates from biological sources.[3][4]
Researchers in July 2010 suggested that carbonate bearing rocks found in the Nili Fossae region of Mars are made up of hydrothermally altered ultramafic rocks. Consequently, hydrothermal activity would have provided sufficient energy for biological activity. Evidence of living organisms could have been preserved.[5]
It is now believed that Nili Fossae came into being as a result of the giant impact that formed the nearby Isidis basin.[6][7] Nili Fossae curves in a concentric fashion around Isidis. It has been suggested that the generation of tectonic features like Nili Fossae can be explained by a "Ring Tectonics theory".[8] Possible evidence of 'buried life' was recently found at Nili Fassae.[9]