Images captured last week by the European Space Agency’s Mars Express orbiter revealed the impact of flooding on a large chunk of the planet’s landscape, including the western portion of the Arda Valles, a dendritic drainage system north of Holden Crater.
Arda Valles, which is 260 kilometers north of the crater and close to Landon Valles, was once home to large quantities of water flowing from the southern highlands, the ESA explained in a statement. This water helped carve Ladon Valles, a river valley located within the Margaritifer Sinus quadrangle region of the Red Planet, and formed a pond in a large basin nearby.
Arda Valles topography. Credit: ESA/DLR/FU Berlin, CC BY-SA 3.0 IGO
In one of the new images captured by Mars Express, the dendritic drainage pattern of the valley is clearly visible, and you can see where several individual streams merged together before they continued down into the smooth-floored impact basin. In addition, a large mound with an 8.5km wide impact crater at its base can be seen in the upper center of one of the new photographs.
The agency explained that this mount could be the remains of an older impact basin, but added that it may have also been affected by sediments transported by the streams that once surrounded it. Those sediments could have accumulated into a fan-shaped deposit or an alluvial fan.
This context image shows part of the Arda Valles region on Mars, a dendritic drainage system located 260 km north of Holden Crater. (Credit: NASA MGS MOLA Science Team)
Clay minerals, essential for life, also visible in the new photos
In addition, the new images depict a larger, 25km wide impact crater located towards the center-right that also appears to have been filled by muddy sediments. Those sediments likely collapsed into the cracked and chaotic crater floor, with its nodules probably indicating the previous levels of the sediments that had partially filled up the hole.
The upper right portion of one image shows a region where the surface was cracked, breaking up into a series of large polygons that ESA scientists believe may have been associated with the loss of subterranean ice and the long-term evaporation of water previously found in the vicinity.
This perspective view in Arda Valles was generated from the main camera’s stereo channels on ESA’s Mars Express. The image focuses on a 25 km-wide impact crater filled with sediments, that have subsequently collapsed into chaotic terrain. The jumbled nodules in the crater rim probably indicate the former level of the infilling sediments. A number of fracture-like features appear to extend out to the smoother basin floor to the right. They could be a later manifestation of stresses due to subsidence or compaction of surface materials. (Credit: ESA)
Fracture-like features visible in the basin’s smooth floor are also believed to be linked to surface stress caused by the compaction of sediments in the basin, and some of the fractures seem to join the central crater to the smoother floor of the basin, the agency said. These features may be more recent manifestation of stresses caused by subsidence or surface material compaction.
Furthermore, in the lower center of the image, just above the bottom-most crater and towards the end of the dendritic channels, researchers have identified a series of light-colored sediment layers as clay minerals. Clay minerals, also known as hydrous aluminium phyllosilicates, typically form in the presence of water and are believed to play a key role in the origin of biological life.
This anaglyph image showing part of the Arda Valles region on Mars provides a 3D view of the landscape when viewed using stereoscopic glasses with red–green or red–blue filters. (Credit: ESA/DLR/FU Berlin, CC BY-SA 3.0 IGO)
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Feature Image: Arda Valles. Credit: ESA/DLR/FU Berlin, CC BY-SA 3.0 IGO
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