HiRISE Science Team wrote:Terraces or Strata on a Crater Slope (ESP_025370_1290)
This observation shows an interesting layered rock outcrop in the southeast Hellas Region. One of the scientific goals is to look for bedding features that might give clues to what deposited the material: subaerial, subaqueous or polar-ice-like?
Structural features cut through the layered material and strata at this location. Could these features be faults or dikes? Additional images of this region may help us find out.
Nathan Bridges wrote:A Volcanic Pit Chain and Dust Avalanches (ESP_026249_2025)
This observation shows a volcanic pit chain in Amazonis Planitia.
Associated with two of the pits are meandering channels that splay into distributary patterns to the north. This suggests that the pits are eruptive centers, with the channels carved by lava.
A close-up image shows the eastern wall of the westernmost pit. The fluid-like streaks are the products of dust avalanches, with the dark color resulting from a thin coating of dust that has been removed from the surface.
The upper wall of the pit shows at least four distinct layers, each representing a sequence of one or more lava flows. A hazy, blueish haze bounds the outer circumference of the pit, perhaps resulting from suspended dust. The plains near the pit appear heavily muted, indicating a thick dust cover.
Laszlo Kestay wrote:Eroded Terrain Near Volcanic Fissures (ESP_026303_1945)
This observation was taken to investigate the topography near the source of fluids from the Cerberus Fossae fractures in the Elysium Planitia region of Mars.
There are distinct channels carved into the terrain here, presumably by floods of water. However, the terrain is coated with lava, and this situation--where flood-eroded channels are completely coated with lava--is seen in many parts of Mars.
This leads some researchers to http://www.uahirise.org/images/2012/det ... jpgsuggest that the channels were actually carved by the flowing lava, and that there was no flood of water. Images like these are helping to test these ideas.
Alfred McEwen wrote:Layered Sediments in Danielson Crater (ESP_026349_1885)
This crater is named for G. Edward Danielson, Jr. (1939–2005), who was instrumental in the development of a series of Mars cameras, from Mariner 4 launched in 1964 to the Mars Global Surveyor launched in 1996.
These layered sediments are of great interest because they are very regular in thicknesses, suggesting some sort of periodic process such as climate change associated with Mars orbital variations.
Credit: NASA/JPL/University of Arizona
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