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PSP_007493_2650_RED_abrowse~0.jpgNorth Polar Layered Deposits covered by Seasonal Frost (MULTISPECTRUM; credits: Lunexit)57 visiteThis image shows an exposure of the North Polar Layered Deposits (NPLD). The layering visible here might have been formed by recent climate variations on Mars, similar to ice ages on Earth.
While the Polar Layered Deposits are mostly water ice, exposures such as this are typically covered by a layer of reddish dust, protecting the underlying ice from evaporation during the Summer. This dusty layer hides the internal composition of the Polar Layered Deposits from view, but variations in the slopes of the surfaces of the layers are still visible.
The slope of each layer is probably affected by the internal composition, so the topography of exposures like this is of interest to scientists. When this image was taken (Northern Spring), the surface was mostly covered by seasonal CO2 frost.
This white frost layer helps to highlight the surface slopes because the visible brightness variations are mainly caused by topographic variations. Therefore, this image will be useful for photoclinometric, or "shape from shading" analyses that can yield topographic maps limited only by the resolution of the image.
MareKromium
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PSP_008778_1685_RED_abrowse.jpgMistery Mounds (MULTISPECTRUM; credits: Lunexit)57 visiteThis image was targeted because a previous MGS-MOC image (R1100035) showed an distinctive field of Mounds on the floor of an ancient, large, filled-in Unnamed Crater.
The origin of the Mounds was unclear, so we hoped that a HiRISE image with higher resolution and color would solve the mystery. The HiRISE image shows much more detail on the Mounds and other rough textures, indicating that this is an eroded bedrock surface, perhaps exposed by removal of an overlying layer of fine-grained materials by the wind.
But how did the rocks form, and why did they erode onto Mounds? It could have been lava or impact ejecta or fluvial sediments, perhaps altered and indurated by groundwater.
The Mounds could be due to how it was deposited — like hummocky Impact Ejecta — or how it was indurated. In other words, we haven't solved the mystery!...
Yet we may get new clues from future images of similar terrains in places where the origin is more interpretable, or from other datasets such as the mineral content determined by CRISM.MareKromium
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PIA10144-DarkFans~0.jpgBright Streaks and Dark Fans (MULTISPECTRUM; credits: Lunexit)57 visiteThe South Polar Region of Mars is covered every year by a layer of Carbon Dioxide (CO2) ice. In a Region called the "cryptic terrain", the ice is translucent and sunlight can penetrate through the ice to warm the surface below.
The ice layer sublimates (evaporates) from the bottom. The Dark Fans of dust seen in this image come from the surface below the layer of ice, carried to the top by gas venting from below. The translucent ice is "visible" by virtue of the effect it has on the tone of the surface below, which would otherwise have the same color and reflectivity as the Fans.
Bright streaks in this image are fresh frost. The CRISM team has identified the composition of these streaks to be Carbon Dioxide.
Nota Lunexit: questa è la surface feature che ha "stimolato" l'immaginazione di Joseph Skipper e Richard Hoagland. Secondo costoro, le "dark features" sarebbero alberi simili ai "pioppi" terrestri... Ogni ulteriore commento ci sembra davvero inutile.MareKromium
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PIA10141-AraneiformTerrain~0.jpgAraneiform and Lace Terrains (MULTISPECTRUM; credits: Lunexit)57 visiteThe South Polar Terrain on Mars contains landforms unlike any that we see on Earth, so much that a new vocabulary is required to describe them. The word "araneiform" means "spider-like".
There are radially organized channels on Mars that look spider-like, but we don't want to confuse anyone by talking about "spiders" when we really mean "channels", not "bugs."
This picture shows an example of "connected araneiform topography", such as terrain that is filled with spider-like channels whose arms branch and connect to each other. Gas flows through these channels until it encounters a vent, where is escapes out to the atmosphere, carrying dust along with it. The dark dust is blown around by the prevailing wind.
This image also shows a different Region where the channels are not radially organized. In this Region they form a dense tangled network of tortuous strands. We refer to this as "lace". MareKromium
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Mawrth_Vallis-The_Waterfall-CC.gifZooming on the "Waterfall" - Mawrth Vallis (GIF-Movie, by Carlo Contu)57 visiteAcquisition date: January, 04, 2008
Local Mars Time: 14:19
Latitude: 23,0° North
Longitude: 341,6° East
Range to target site: 309,9 Km
Original image scale range: 31 cm/pixel (with 1 x 1 binning) so objects ~93 cm across are resolved
Map projected scale: 25 cm/pixel and North is up
Map projection: EQUIRECTANGULAR
Emission angle: 22,7°
Phase angle: 60,1°
Solar incidence angle: 38°, with the Sun about 52° above the horizonMareKromium
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PSP_008927_2010.jpgUnnamed Crater in Nili Fossae Region (True Colors; credits: Dr M. Faccin)57 visitenessun commentoMareKromium
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PSP_008927_2010_RED-00.jpgPossible MSL Landing Site in Nili Fossae Trough (natural colors; credits: Lunexit)57 visiteNili Fossae Trough is a linear trough about 25 Km wide, formed in response to the creation of the Isidis Basin.
Nili Fossae has diverse deposits, some containing Phyllosilicates (Clay Deposits which typically form in the presence of water), and others with the minerals Olivine and Pyroxene.
This image is part of a series covering the 25 km Landing Ellipse; they are used to determine the safest possible Landing Site for the Mars Science Laboratory Rover. In this frame, relatively smooth rock exposures is visible, as well as sand ripples and some small knobs. There are few large rocks in the area, while the surface seems to be mostly flat, fractured rock.
This landscape is located in the South-Eastern part of the Landing Ellipse.MareKromium
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Psp_008753_1880_red.jpgLava-filled Crater in Elysium Planitia (natural colors; credits: Lunexit)57 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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Psp_008779_1905_red.jpgThe Head of Athabasca Valles (natural colors; credits: Lunexit)57 visiteThis observation is located at the head of the Athabasca Valles Channel System, which lies just North of Mars’ Equator, in a low-elevation Region known as Elysium Planitia.
Athabasca Valles has an interesting geologic history. It was probably carved by one or more catastrophic floods of water, but more recently, a flood of lava coursed through the channel system. Both the water and the lava erupted from a few discrete points (or “vents”) along the Cerberus Fossae, a 1600-Km(1000-mile) long network of extensional (or “normal”) faults. The two prominent troughs that cut across the Southern end of this HiRISE image are part of the Cerberus Fossae. They are distinct fault segments that overlap at their tips, as one tapers in and the other pinches out.
They were not always as wide as they are today. Erosional processes have widened the troughs over time. Major eruptions occurred along both of the fault segments seen in this image, though they occurred to either side of the imaged area itself. Lava that erupted from the western vent covers the northern half of the image. The lava has raised, lobate margins and is slightly darker in tone than the older cratered plains it embays. The lava also has a banded appearance of subtly contrasting lighter and darker tones, that correspond to variations in surface roughness.
The bands are concentric to a vent located immediately west of the imaged area. Unfortunately, vents along the Cerberus Fossae are not well preserved.MareKromium
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PSP_006271_2210_RED_abrowse.jpgPrimary and Secondary Craters in Arcadia Planitia (MULTISPECTRUM; credits: Lunexit)57 visiteThese unusual craters were spotted in Arcadia Planitia, which is part of an extensive region of Mars blanketed by a thick layer of bright dust.
Light southeasterly winds during southern spring and summer blow the dust towards the northwest (top left of the picture in the cutout above). The dust is trapped temporarily in the lee of crater rims, both inside the craters and along the outside rims where they form streamers that resemble St. Nick’s beard.
MareKromium
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PSP_009162_1570.jpgFresh 5-Kilometer Diameter Rayed Crater (False Colors; credits: Dr M. Faccin)57 visiteThe crater featured in this scene formed on top of ejecta from a nearby rampart crater, located to the North.
The crater’s distinct rim indicates that it is relatively young. There is bright material on many of the crater walls that might be landslides of dust or another bright substance.
The mounds of material on the crater floor probably formed during late stages of crater’s own formation. The crater floor is speckled with even smaller craters.MareKromium
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PSP_009155_1480_RED.jpgGullies and Bedrock Exposures in Impact Crater Wall (natural colors; credits: Lunexit)57 visiteThis image shows a rather pristine crater with Gullies and Bedrock Exposures. The Gullies are mostly on the South-Facing (such as the Poleward facing) wall. Some of the gully channels are very sharp, indicating that they have not been modified much since they formed.
Other channels criss-cross each other, demonstrating that there were multiple periods of activity. Scientists do not know how closely these were spaced in time.
The South and East walls of the Crater (upper right of the frame) have very distinct bright layers. These layers are possibly Ancient Bedrock. These walls also have what appear to be bright Landslides.MareKromium
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