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ESP_017693_1795_RED_abrowse.jpgThermal Anomaly in Aeolis and Zephyria Regions (Saturated Natural Colors; credits for the additional process. and color.: Dr Paolo C. Fienga - Lunexit Team)129 visiteThis image is taken of an interesting Linear Surface Feature in the Aeolis and Zephyria regions. Using the daytime IR imaging data from the THEMIS instrument, this feature has a higher daytime temperature than its surroundings while also being relatively dark.
When viewed at full HiRISE resolution, this area contains Sand Ripples with some consolidated, Bedrock-like material poking through. These Bedrock Outcrops are more pronounced along the southern portion of the image and are most apparent in the region of the Thermal Anomaly. The Outcrops trend generally East-West and appear sculpted by aeolian erosion.
In the area of the Anomaly, the sand between these Outcrops has a darker tone and gradually blends with the lighter material to either side. This darker sand may be the reason why the material has a "hot" signature compared to its surroundings, because dark materials absorb sunlight more efficiently.
Features similar to the one in this image help researchers to characterize such features and to understand whether such exposures may indicate possible Hydrothermal Fissures, or perhaps be just an exposure of a darker underlying material.
Written by: Shawn Hart and Ginny GulickMareKromium
(1 voti)
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ESP_017581_1765_RED_abrowse.jpgExposed Light Material in Upland Region in Aureum Chaos (Natural Colors; credits for the additional process. and color.: Dr Paolo C. Fienga - Lunexit Team)127 visiteThe Plateau visible in this image is located within Aureum Chaos. Chaotic Terrains on Mars are blocky, fractured regions of flat-topped hills, plateaus, plains and depressions thought to have formed by the collapse of the heavily cratered uplands.
Large Outflow Channels appear to emerge from Aureum Chaos and other Chaotic Terrains leading researchers to posit that these large collapse regions were formed by the catastrophic release of ground water. Aureum Chaos is located just to the North-East of Valles Marineris adjacent to Margaritifer Terra, and it has a diameter of approximately 368 kilometers.
The steep-sided Plateau in this image has a sharp, undulating surface possibly etched out and eroded by persistent winds. These same winds may well have transported the resulting sediment to the surrounding plains helping to form the Dunes below. The Plateau slopes are steep and consist of a series of parallel bright, more resistant cliff forming layers and darker, less resistant slope material. A good way to see the differences in color between the plateau's bright layered deposits and the surrounding area is to look at some of the blocks that have fallen off the cliff onto the the dark sands below.
By studying areas of Mars such as this one, researchers hope to understand how the chaos regions formed and how their formation related to the release of ground water to form the outflow channels, if indeed the two are connected in this way.
Written by: Shawn Hart and Ginny GulickMareKromium
(1 voti)
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ESP_017405_2270_RED_abrowse.jpgNorthern Hemisphere Gullies on West-Facing Crater Slope (Natural Colors; credits for the additional process. and color.: Dr Paolo C. Fienga - Lunexit Team)162 visiteThis image shows the Eastern (West-facing) side of an Unnamed Impact Crater in the Mid-Latitudes of the Northern Hemisphere.
Like many Mid-Latitude Craters, this one has Gullies along its Walls that are composed of Alcoves, Channels and Debris Aprons. The origins of these Gullies have been the subject of much debate; they could have formed by flowing water, liquid Carbon Dioxide, or dry granular flows. The orientation of these Gullies is of interest because many Craters only contain Gullies on certain Walls, such as those that are Pole-facing. This could be due to changes in orbital conditions and differences in solar heating along specific Walls.
Many of the other features observed in and around this Crater however are indicative of an ice-rich terrain, which may lend credence to the water formation hypothesis, at least for the Gullies visible here. The most notable of these features is the "Scalloped Terrain" in and around the Crater.
This type of Terrain has been interpreted as a sign of surface caving, perhaps due to sublimation of underlying ice.
Another sign of ice is the presence of parallel lineations and pitted material on the Floor of the Crater, similar to what is referred to as concentric Crater Fill. Parallel linear cracks are also observed along the Crater Wall over the Gullies, which could be due to thermal contraction of ice-rich material.
All of these features taken together are evidence for ice-rich material having been deposited in this Region during different climatic conditions that has subsequently begun to melt and/or sublimate under current conditions. More recently, Aeolian Deposits have accumulated around the Crater as evidenced by the parallel ridges dominating the landscape.
Dust Devil Streaks are also visible crossing the Aeolian Ridges.
Written by: Dan BermanMareKromium
(1 voti)
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PSP_002478_1770_RED_abrowse-00.jpgEroding Crater Fill (CTX Frame - Natural Colors; credits for the additional process. and color.: Dr Paolo C. Fienga - Lunexit Team) 107 visiteThis image shows the edge of a Mound (----> terrapieno) of sediments in the center of a large Impact Crater near Amenthes Planum.
The Mound probably once filled much more of the Crater, but it is now eroding away. A broad view shows several small plateaus which have likely been preserved by a relatively resistant cap layer, while other levels are exposed elsewhere.MareKromium
(1 voti)
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PSP_002478_1770_RED_abrowse-01.jpgEroding Crater Fill (EDM - Natural Colors; credits for the additional process. and color.: Dr Paolo C. Fienga - Lunexit Team)94 visiteThis EDM shows several types of Layers exposed in a Pit. These variations point to a relatively complex geologic history at this site.
Some Layers appear to be fracturing into boulders which roll downslope, while others appear relatively smooth. There are also variations in tone, from light to dark. This diversity may be due to different types of rock, as well as varying strength.
Images such as this one indicate that rocks formed on Mars in a variety of ways, and by careful analysis it may be possible to deduce some of the history that has produced the geology at this site.MareKromium
(1 voti)
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ESP_017348_1910_RED_abrowse-00.jpgPolygonal Ridges in Gordii Dorsum (CTX Frame - Natural Colors; credits for the additional process. and color.: Dr Paolo C. Fienga - Lunexit Team)84 visiteThis image from the Gordii Dorsum Region of Mars shows a large area covered with Polygonal Ridges in an almost geometric pattern.
The Ridges may have originally been Dunes which hardened (indurated) through the action of an unknown process.
Groundwater might have been involved.MareKromium
(1 voti)
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ESP_017348_1910_RED_abrowse-01.jpgPolygonal Ridges in Gordii Dorsum (EDM - Natural Colors; credits for the additional process. and color.: Dr Paolo C. Fienga - Lunexit Team)121 visitenessun commentoMareKromium
(1 voti)
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ESP_016280_2655_RED_abrowse.jpgMartian Tears... (possible Natural Colors; credits: Dr Paolo C. Fienga - Lunexit Team)62 visitenessun commentoMareKromium
(1 voti)
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ESP_016288_2610_RED_abrowse.jpgHigh Northern Latitudes (possible Natural Colors; credits: Dr Paolo C. Fienga - Lunexit Team)56 visitenessun commentoMareKromium
(1 voti)
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PSP_001398_2615_RED_abrowse.jpgExposure of NPLD with "Unconformities" (Natural - but enhanced - Colors; credits: Dr Paolo C. Fienga - Lunexit Team)81 visiteThis image shows a portion of the North Polar Layered Deposits (NPLD). The NPLD are layers that have been deposited over an extensive area at both Poles, possibly throughout Martian History. They likely contain ice-rich and dust-rich layers, with the darker layers being probably more dust-rich than the bright layers.
The NPLD holds clues to past climate regimes similar to ice cores on Earth. Several of the layers occur in fairly regular sequences, as seen in this image, suggesting that Mars underwent cyclic climate changes in the past.
Towards the top left side of the image, there is a series of layers that appears truncated at an angle, forming what geologists call "Angular Uncomformity". They typically form by first laying down a series of continuous beds. Then erosion cuts through the beds at an angle. Aferwards, a new set of beds are laid over this partially eroded sequence. A similar Unconformity exists at the bottom right of the image.MareKromium
(1 voti)
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PSP_003540_1735_RED_browse~0.jpgFaults and Folds in West Candor Chasma (Natural Colors; credits: Lunexit)61 visiteThis image shows various interesting structures along the Floor of Candor Chasma, a major canyon of Valles Marineris.
The rocks along the floor of the chasma consist of multiple layers of light-toned material, possibly windblown or water-lain sediment. These layers have been shifted along faults and also folded, giving the layers an apparent wavy appearance as they are exposed at the Surface through erosion.
Some waviness in the Layers may also have formed as these sediments were laid down (for example, in Dunes or large Ripples. Detailed mapping of these Faults and Folds may help reveal the origin of these Layered Deposits and if water played any role in their formation.MareKromium
(1 voti)
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PSP_001415_1875_RED_abrowse.jpgAlluvial Fans in Mojave Crater (Natural Colors; credits: Lunexit)81 visiteAptly-named Mojave Crater in the Xanthe Terra Region has Alluvial Fans that look remarkably similar to landforms in the Mojave Desert of South-Eastern California and portions of Nevada and Arizona.
Alluvial Fans are "fan-shaped deposits of water-transported material" (---> Lat.: alluvium). They typically form at the base of hills or mountains where there is a marked break, or flattening of slope.
They typically deposit big rocks near their Mouths (close to the mountains) and smaller rocks at greater distances. Alluvial Fans form as a result of heavy desert Downpours, typically "Thundershowers" (Nota Lunexit: piogge torrenziali che occorrono durante violenti temporali, per lo più di tipo tropicale).
Because deserts are poorly vegetated, heavy and short-lived Downpours create a great deal of erosion and nearby deposition.
There are Fans inside and around the outsides of Mojave Crater on Mars that perfectly match the morphology of Alluvial Fans on Earth, with the exception of a few small impact craters dotting this Martian Landscape.
Channels begin at the apex of topographic Ridges, consistent with precipitation as the source of water, rather than groundwater. This remarkable landscape was first discovered from Mars Orbital Camera images. Mars researchers have suggested that impact-induced Atmospheric Precipitation may have created these unique landscapes.
This HiRISE image at up to 29 cm/pixel scale supports the Alluvial Fan interpretation, in particular by showing that the sizes of the largest rocks decrease away from the Mouths of the Fans.MareKromium
(1 voti)
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