Mars Reconnaissance Orbiter (MRO)
|
|
|
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
|
|
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
|
|
PSP_002542_1080_red-1.jpgDefrosting Dunefield (Absolute Natural Colors; credits for the additional process. and color.: Dr Paolo C. Fienga - Lunexit Team)108 visiteThis image is a close-up view of defrosting patterns on the Dunes located at the bottom of Richardson Crater. The Frost is a combination of frozen CO2 and some water ice that covers the Dunes in the Winter and Spring. As the seasonal Frost sublimes away, odd features such as Spots, Fans and Streaks form. Small Dark Streaks on the Dune "Slip-Face" Slopes may be where recent avalanches of sand, or perhaps wind, has moved the dark sand underlying the Frost, or where frost has been removed to expose the sand. Alternatively, the Dark Streaks may be patches of coarse-grained ice that are clear enough so that the dark material below the ice is visible. The Slip-Faces indicate that the general direction of sand transport is (meaning the that the Dominant Winds blow) from the right to the left across the image.
It has been hypothesized that the Dark Spots and Fans may be "Geysers" or "Cold Gas Jets" that form when sublimation processes trap gas at the bottom of the ice. The gas is released through cracks in the ice, entraining Dust from below the ice and scattering it onto the Surface to form the Dark Spots and Fans. The high resolution, stereo, and low light imaging capabilities of HiRISE has provided new insight into the processes that form these features. Repeated imaging in a variety of locations will provide a record of their development and evolution. MareKromium
|
|
PSP_002545_1430_RED_browse-00~0.jpgJuncture of Two Branches of Dao Vallis (ctx frame - possible True Colors; credits: Lunar Explorer Italia)53 visiteMartian outflow channels are believed to be some of the largest features formed from the catastrophic flooding that scoured the landscape during ancient times. The source of the water likely originated in the subsurface and was somehow disturbed, depressurizing an aquifer, causing a sudden burst of water onto the surface.
This image shows multiple branches of the outflow channel Dao Vallis, which flows towards the West (down), ending near Hellas Basin. Although it is not clear exactly where the water that created these floods ended up, it is possible that Dao Vallis and its neighboring outflow channel, Niger Vallis, deposited water in Hellas Basin and formed a short-lived lake. Within the floor of Dao Vallis is material that appears striped, known as "lineated valley fill".
Valley fill material is thought to be ice-rich material that has flowed or been deposited onto the floor. Several lineations or "flow lines" appear to merge towards the upper left of the scene which supports this idea that the fill materials flowed, similar to slow-moving glacial material on Earth.
Also present in this scene is a mantling deposit which drapes much of the mid-latitudes of Mars. The deposit or "mantle" can be seen on south-facing slopes of positive-relief features, appearing as if its sliding off the walls. The mantle material is thought to be ice-cemented dust that was deposited during times when snowfall occurred on Mars.MareKromium
|
|
PSP_002545_1430_RED_browse-01~0.jpgJuncture of Two Branches of Dao Vallis (edm - possible True Colors; credits: Lunar Explorer Italia)53 visiteHiRISE images, such as this one (here, approximately 680 mt across), show that the mantled unit is textured and full of boulders, which contrasts with the smooth appearance of this material in MOC images.MareKromium
|
|
PSP_002574_1865_red-PCF-LXTT.jpgLayered Rocks in Arabia Terra (Natural Colors; credits for the additional process. and color.: Dr Paolo C. Fienga - Lunexit Team)160 visitenessun commentoMareKromium
|
|
PSP_002590_1765_RED_abrowse-00.jpgFine Layers in Juventae Chasma (CTX Frame - Natural Colors; credits for the additional process. and color.: Dr Paolo C. Fienga - Lunexit Team)75 visitenessun commentoMareKromium
|
|
PSP_002590_1765_RED_abrowse-01.jpgFine Layers in Juventae Chasma (EDM - Natural Colors; credits for the additional process. and color.: Dr Paolo C. Fienga - Lunexit Team)71 visitenessun commentoMareKromium
|
|
PSP_002620_1410_RED_browse-00.jpgGullies on the edge of Newton Basin (context image)53 visiteThis image shows a portion of two impact craters on the floor of Newton Basin where a smaller crater formed within a earlier larger one.
The larger crater's North rim can be seen diagonally (South-West/North-East) across the image and the smaller crater's north rim is near the right-side of the image.
Along the interior wall of the larger crater, several gullies have incised into the wall of the Crater. MareKromium
|
|
PSP_002620_1410_RED_browse-01.jpgGullies on the edge of Newton Basin (extra-detail mgnf)53 visiteThe gullies start near the top of the wall and can be traced across a break in slope partway down the wall (see here, 750 mt across). This break in slope occurs along the entire portion of the Crater wall in this image. The gullies appear shallower just above the break in slope, and deeper below the slope break.
This suggests that the fluid which eroded and carved out the wall materials forming the gullies, increased in velocity after the slope break, creating a deeper section of the gully.MareKromium
|
|
PSP_002630_1695_RED_abrowse.jpgMelas Chasma (Natural Colors; credits for the additional process. and color.: Dr Paolo C. Fienga - Lunexit Team)54 visiteThis observation shows an Outcrop of bright material in Melas Chasma, part of the giant Valles Marineris Trough (Canyon) System.
These Troughs contain many bright Deposits, often layered. The origin of these materials is still not known, but is the subject of much study because answering this question will provide important information regarding the Geologic History of Mars.
In this image, some layers are visible, but much of the surface has a strange scalloped texture.
The cause of this texture is unclear, but it is likely related to the mechanism of erosion of these Deposits as well as their physical nature. These materials are being eroded by winds, forming elongated ridges called Yardangs.
These winds may also be responsible for the small-scale scalloped texture.
Also, Landslides have produced some Talus Cones, composed of piles of loose debris; these are visible in places, mostly near the base of the Mound, as wedge-shaped features containing many Boulders.MareKromium
|
|
PSP_002728_1645_RED_abrowse.jpgThe Dunes of Herschel Crater (Saturated Natural Colors; credits for the additional process. and color.: Dr Paolo C. Fienga - Lunexit Team)98 visiteThis image shows Dunes on the floor of Herschel Crater. The Steep Faces (a.k.a.: "Slip-Faces") of the Dunes are oriented downwind, in the direction of their motion. One feature of particular interest is the dune-free area downwind of the Crater towards the right side of the frame. Some sand has been trapped in the Crater, but the Crater prevents the Dunes from migrating directly downwind. Sand Dunes form naturally as a result of the transport of sand by the wind.
The Dunes in this image are somewhat crescent-shaped, but are being extended and distorted downwind and merging with nearby Dunes; this complex behavior is common in Dunefields on Earth.
In the left side of the image the sand lies in sheets rather than well-defined Dunes. At high resolution, the Dunes' Surface are covered in small Ripples and Scallops, also shaped by the wind. MareKromium
|
|
| 2237 immagini su 187 pagina(e) |
 |
|
|
|
|
103 | |
|
|
|
|
