Mars Reconnaissance Orbiter (MRO)
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Psp_002538_1720_red.jpgJust like Thaumasia: more "bright" dunes in Ius Chasma53 visiteIus Chasma is one of several canyons that make up Valles Marineris, the largest canyon system in the Solar System.
The canyons likely formed by extension in association with the development of the Tharsis plateau and volcanoes to the West. Wind and possibly water have modified the canyons after they formed.
This HiRISE image shows the floor of Ius Chasma. The floor is bounded to the North and South by higher standing wallrock, with a few exposures of wallrock seen in the North (Sx) of the picture. Much of the floor is covered by ripples that are oriented approximately North-South, indicating an East to West wind flow, parallel to the orientation of Ius Chasma.
Layered deposits and bright patches of material are also seen along portions of the Ius Chasma floor. The layered deposits appear distinct in morphology from the nearby wallrock. These layered deposits could be lava flows, sediments deposited in a former lake, or fines that settled out from the atmosphere over time, such as dust or volcanic ashes.
The bright outcrops visible further south in the image have been seen elsewhere in Valles Marineris as well as other locations on Mars and tend to have mineral signatures consistent with sulfates. Data from the CRISM instrument (also on Mars Reconnaissance Orbiter) of the composition of these bright patches in Ius Chasma could shed insight into their origin. MareKromium
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Psp_002839_1825_red.jpgAram Chaos' Sediments (False Colors)54 visiteAram Chaos appears to be a former impact crater. The terrain is disrupted, giving it a chaotic appearance (hence the name "chaos"). Scientists have postulated that a lake may have once existed inside the crater and sediments were laid down within the lake.
The mineral Hematite (rich in Iron) has been detected by orbiting spacecraft within Aram Chaos. Hematite has been identified in several other locations on Mars, including at the MER Landing Site in Meridiani Planum. The Hematite at both Meridiani and Aram Chaos most likely formed by precipitation in water.
This HiRISE image shows the light-toned sediments inside Aram Chaos that could have formed in a former lake. Unfortunately, dark debris now obscures much of this sediment, making it difficult to view and interpret the rocks. The light-toned layered deposit in the south (Dx) of the image is higher standing and has a pitted surface.
Circular structures with dark centers are likely to be impact craters that have been partly filled with dark debris, including sand. More irregular depressions appear to result from erosion of layered beds within the sediments. Wind could erode materials that are slightly weaker more quickly and produce the irregular topography seen along the surface of the deposit.
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Psp_007242_2650_red.jpgChasma Boreale (natural colors; credits: Lunexit)56 visitenessun commentoMareKromium
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Psp_008210_2415_red~0.jpgKnobs and Small Craters with Ice in Northern Arcadia Planitia (natural colors; credits: Lunexit)65 visitenessun commentoMareKromium
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Psp_008216_2325_red.jpgPeriglacial Surface Features in the Northern Plains (natural colors; credits: Lunexit)54 visitenessun commentoMareKromium
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Psp_008222_1640_red.jpgCollpse Pits along Claritas Rupes (Saturated and Enhaced Natural Colors; credits for the additional process. and color.: Dr Paolo C. Fienga - Lunexit Team)72 visitenessun commentoMareKromium
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Psp_008238_1555_red.jpgWell-Preserved Unnamed Crater South of Gusev Crater (natural colors; credits: Lunexit)54 visitenessun commentoMareKromium
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Psp_008240_2500_red.jpgLouth Crater South Rim (Extremely Enhanced Natural Colors; credits for the additional process. and color: Dr Paolo C. Fienga - Lunexit Team)56 visitenessun commentoMareKromium
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Psp_008680_2050_red.jpgCharacterize Surface Hazards and Science of Possible MSL Rover Landing - Mawrth Vallis (natural colors; credits: Lunexit)54 visitenessun commentoMareKromium
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Psp_008706_1765_red.jpgCharacterize Surface Hazards and Science of Possible MSL Rover Landing Site - Equatorial Regions/Meridiani Planum (natural colors; credits: Lunexit)54 visitenessun commentoMareKromium
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Psp_008719_1815_red.jpgCharacterize Surface Hazards and Science of MSL Rover Landing Site - Equatorial Regions/Meridiani Planum (natural colors; credits: Lunexit)54 visitenessun commentoMareKromium
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Psp_008753_1880_red.jpgLava-filled Crater in Elysium Planitia (natural colors; credits: Lunexit)54 visiteElysium Planitia is a part of the Martian Lowlands that has been repeatedly covered by vast floods of lava. This image shows an older Impact Crater that has been filled by one of the youngest of those lava floods.
Only sections of the circular rim of the Crater remain uncovered. The lava surface consists of ridged plates that have rafted apart with smoother lava filling between the plates. The ridges formed as the solidifying lava crust was crumpled by compression, and the gaps between the plates formed as the crust was pulled apart. Similar compression and extension of lava crust has been observed in the largest lava flows in Iceland.
The most puzzling aspect of this image is that the lava in the floor of the Crater appears to have sunk down compared to its surroundings. This happened after a thick crust had formed on the lava. The most likely explanation is that the last molten lava inside the flow drained away through a now buried gap in the crater rim.
A final point of interest are the small circular cones visible near the center of the Crater. These formed when ground water (or ice) was turned to steam by the heat of the lava flow. This steam exploded through the flow, producing the small cratered cones.MareKromium
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