Colin Dundas wrote:Channel in the Cerberus Palus Region (ESP_032066_1860) (HiClip)
This image shows the end of a small channel near Athabasca Valles on Mars. Athabasca is an example of a Martian "outflow channel", likely carved by a massive flood of groundwater. However, it is now coated with a thin veneer of lava, following a massive volcanic eruption that flowed down the channel.
This smaller channel is also covered by the same lava flow. It might have originally been carved by water and later draped by lava that partially drained away, but it is also possible that hot, swift lava cut down into the ground. In either case, the reason a channel formed here is the ridge running across the image. Once fluid reached the top of this ridge, flow was concentrated there and carved a deeper channel.
The upstream half of the channel is visible in PSP_008265_1860.
Colin Dundas wrote:An Icy Crater on Mars (ESP_032118_1085) (HiClip)
HiRISE has observed more than 200 new craters on Mars. These craters are first visible as new dark spots by the MRO's Context Camera (CTX), which can view much larger areas, and then imaged by HiRISE for a close-up look. The dark spots are most easily seen when the surface is light and dusty, so most of the new craters that we find are in dusty areas like the large volcanoes on Tharsis.
Mars has ground ice at high latitudes, and when new craters form there, they dig up the ice. Until this image, this had only been seen on the Northern plains, because the Southern highlands have less dusty surfaces and it is hard to find new craters there. This crater is on an outlier of the South Polar layered deposits, a thick stack of layers near the south pole made of ice and dust.
It is not a surprise to find that these layered deposits are icy! However, the ice must be clean (without much dust) to stay bright long enough for HiRISE to see it, which gives us another piece of evidence that the layers are mostly ice. The layered deposits around here are covered with a layer of dust, but this crater tells us that the cover isn't very thick.
This crater also threw out debris that formed rays, including some very small "secondary" craters. None of these smaller craters was large enough to dig up ice.
Over time, finding more of these craters all over Mars will help us to understand how much ice the planet has and where it is located.
Cathy Weitz wrote:Colorful Sediments near Hellas Basin (ESP_032359_1525) (HiClip)
Excellent exposures of light-toned layered deposits occur along the northern edge of Hellas Basin, like those visible in this enhanced color image.
Some of these layered sediments have hydration features in CRISM data, and the various colors visible in this image suggests several different compositions may be present throughout the strata. The sediments may have been emplaced by hydrothermal activity associated with the impact event that created Hellas Basin.
Alternatively, they could be younger deposits that formed within this region when a lake existed here. Studies of the deposits using several data sets could distinguish between these two origins and may result in additional hypotheses for their formation.
Matthew Chojnacki wrote:Opportunity's Journey at Endeavour Crater (ESP_032573_1775) (HiClip)
Opportunity has been on the western rim of 20-kilometer-diameter Endeavour Crater in Meridiani Planum for about two years investigating the 3-4 billion-year-old sedimentary layers of Cape York. Now, more than a decade after the Mars Exploration Rover Opportunity's 2003 launch, this HiRISE image captures the rover traversing south to new science targets and a winter haven at Solander Point.
Opportunity's destination at Solander Point is thought to have abundant clay-bearing rocks (as detected from orbit) as part of well-exposed geological layers that are sure to provide vital clues to Mars' watery past. In addition, the north-facing slopes at Solander Point will maximize the amount of solar energy the rover can collect and allow a more productive southern winter science campaign.
Opportunity has been investigating younger sedimentary units exposed in the smaller craters of Eagle, Endurance, and Victoria for the last 9.5 years. By driving across Meridiani to Endeavour Crater, Opportunity currently holds the US space program's all-time record for distance traversed on another planetary body at greater than 36 kilometers or 22 miles.
This image, a HiRISE digital terrain model, and cameras on board Opportunity aid rover drivers in identifying safe routes. Additionally, they assist NASA geologists in finding attractive science targets for future investigation.
This Image was acquired on 8 July 2013, or Sol 3361 of the rover's surface mission 10 years after launch.
Credit: NASA/JPL/University of Arizona
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