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HiRISE image (PSP_001942_2310) shows a crater approximately 11 km (7 miles) in diameter, located in Acidalia Planitia, part of the Northern Plains. Several features in and around this crater are suggestive of fluids and ice at and near the surface. The south-looking (or equator facing) walls of this crater are cut by numerous gullies such as the ones shown in this image's cutout (500 x 600 m or 550 x 650 yards), with well developed alcoves, sinuous channels, and terminal fan deposits. These gullies seem to originate at the same height, suggesting that the carving agent may have emanated from one single layer exposed in the crater's wall. Contrastingly, no gullies are observed in the north-looking (or pole facing) wall of this crater. Terrestrial gullies very similar to the ones shown in this image are produced by surface water. The arrows in the cutout show fissures that may indicate detachment of surficial materials possibly held together by subsurface ice, sliding en masse down the crater's wall. The muted topography of the crater and its surroundings, the relatively shallow floor (300 m or 330 yards), the convex slope of its walls-all are consistent with ice being present under the surface, mixed with rocks and soil. Ice would have acted as a lubricant, facilitating the flow of rocks and soils and hence smoothing landscape's features such as ridges and craters' rims. The concentric and radial fissures in the crater's floor may indicate decrease of volume due to loss of underground ice. Piles of rocks aligned along these fissures and arranged forming polygons are similar to features observed in terrestrial periglacial regions such as Antarctica. Antarctica's features are produced by repeated expansion and contraction of subsurface soil and ice, due to seasonal temperature oscillations. The funnel-shaped depressions visible in the crater's floor could be collapse pits, further evidence of ice decay; alternatively, they could be smoothed-out impact craters.
Signs of Fluids and Ice in Acidalia Planitia
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Phoenix Lander on Mars (Stereo)
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Phoenix Lander on Mars
Depth-to-Ice Map of a Southern Mars Site Near Melea Planum
Depth-to-Ice Map of a Southern Mars Site Near Melea Planum
Depth-to-Ice Map of an Arctic Site on Mars
Depth-to-Ice Map of an Arctic Site on Mars
This HiRISE image shows a portion of interior layered deposits (ILD) in Juventae Chasma. Juventae Chasma is a large depression near the equatorial canyon system Valles Marineris. The scene is along the top of a mound of layered deposits on the floor of Juventae Chasma. Dunes are seen in the low-lying, darker regions. Very fine layers are also seen (see subimage, approximately 1 km across). Understanding what kinds of materials formed the layers, how they were set in place, and how they have evolved will provide insight into Martian geologic history.
Interior Layered Deposits in Juventae Chasma
This artist's conception of NASA's Mars Science Laboratory portrays use of the rover's ChemCam instrument to identify the chemical composition of a rock sample on the surface of Mars.
Mars Science Laboratory Using Laser Instrument, Artist's Concept
NASA's Mars Science Laboratory, a mobile robot for investigating Mars' past or present ability to sustain microbial life, is in development for a launch opportunity in 2009.
Mars Science Laboratory with Power Source and Extended Arm, Artist's Concept
A Change in the Weather
A Fresh Crater Drills to Tharsis Bedrock
This is a close-up image of the area in the vicinity of the Pathfinder landing site
Landing Site Region
PIA09098-PSP_001513_2650_RED_new.tif
Pits in Polar Cap
This HiRISE image covers the southwest portion of the terraces and floor of Holden Crater situated in southwest Margaritifer Terra. The HiRISE sub-frame shows the most clearly-evident image of a megabreccia on Mars. Breccia is a rock typically consisting of rock fragments of various sizes and shapes that have been broken, tumbled and cemented together in sudden geologic event (e.g., a landslide, a flashflood or even an impact-cratering event). If it were not for the dark sandy dunes dispersed through out the sub-image, this image could easily fool an expert into thinking that this image is actually a photograph of a hand sample of an impact breccia. The prefix "mega" implies that the breccia in the sub-image consists of clasts, or rock fragments, that are typically larger than a large house or a building. The rectangular megaclast near the center of the image is a colossal 50 x 25 meters (~150 X 75 feet). As mentioned in the transition image caption for Holden crater (TRA_000861_1530), the crater likely experienced extensive modification by running water, which is supported by observations of drainage and deposition into the crater from a large channel (Uzboi Valles) breaching Holden's southwest rim. While it is possible that the megabreccia formed from a catastrophic release of water into the crater, a more likely possibility is that it formed from the impact that created the approx. 150 km-in-diameter Holden crater. Popigai Crater, a terrestrial crater of half the size of Holden, possesses a similar occurrence of megabreccia with a similar range in megaclast size to the Holden crater example. An impact-generated megabreccia deposit, as observed in terrestrial craters, typically lies beneath the crater floor, so the exhumation of the megabreccia may be the result of down-cutting and erosion of water that once flowed through Uzboi Valles.
Holden Crater Megabreccia: A Telltale Sign of a Sudden and Violent Event
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Radar View of Layering near Mars' North Pole, Orbit 1512
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Radar View of Layering near Mars' South Pole, Orbit 1334
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Clay at Nili Fossae
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Gypsum at Olympia Undae
PIA09077-SS4-1M210211247EFF758ZP2957M2M1.tif
Big Spherules near 'Victoria'
PIA09084-SS3-1165600218_27856_Sol1019B_P2436_L2gam2.tif
View of 'Bottomless Bay' on Rim of 'Victoria' (Altered Contrast)
PIA09085-SS2-1165600921_28885_Sol970B_P2400_L257Fsub.tif
View of 'Cape St. Mary' from 'Cape Verde' (False Color)
PIA09086-SS1-1165335388_14936_Sol1006B_P2429_L257F.tif
View of 'Cape Verde' from 'Cape St. Mary' in Late Morning (False Color)
PIA09076-RP3-1334-o-gram.tif
Interpreting Radar View near Mars' South Pole, Orbit 1334
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Interpreting Radar View near Mars' South Pole, Orbit 1360
PIA09074-RP1-1512-o-gram.tif
Interpreting Radar View near Mars' North Pole, Orbit 1512
PIA09092-RA6-mi-king-george_unlabeled.tif
'King George Island' Brushed
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'King George Island' Brushed
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