Landslides in Ganges Chasma
Lobes from several enormous landslides are visible along the floor of Ganges Chasma.
This image shows a portion of Ganges Chasma, a several kilometers-deep side canyon at the east end of the Valles Marineris canyon system.
Ganges Chasma slices through almost 5 kilometers of the martian crust and reveals ancient rocks and layers in the walls of the canyons that would otherwise be unseen. Lobes from several enormous landslides are visible along the floor of the canyon. Material in a landslide off the north wall of the canyon flowed more than 17 kilometers across the canyon floor, eventually coming to rest atop an older landslide from the south wall, that had travelled nearly as far.
Landslides have very characteristic morphologies on Earth, which they also display on Mars. These morphologies include a distinctive escarpment at the uppermost part of the landslide, called a head scarp, a down-dropped block of material below that escarpment that dropped almost vertically, and a deposit of debris that moved away from the escarpment at high speed.
The image was taken by the High Resolution Stereo Camera (HRSC) on board ESA’s Mars Express spacecraft and has not yet been officially released by ESA.
Image Credit: ESA/DLR/FU Berlin (G. Neukum)/astroarts.org
Perspective view of landslide features
in Ganges Chasma.
Perspective view of Ganges Chasma, looking east.
The vertical exaggeration is 2.
Image Credit: ESA/DLR/FU Berlin (G. Neukum)/astroarts.org
Further reading:
W. J. Burns – Chapter 4: Landslide Features and Their Relative Ages (PDF; 333 KB)
Arsia Mons
Collapse features on the southern flank of
the giant shield volcano Arsia Mons.
This colour composite from infrared, green and blue channel images shows a zone of collapse features on the southern flank of the giant shield volcano Arsia Mons. The total height difference in the land surfaces in this scene is about 7 kilometers, and some individual collapse pits have a depth of more than 2 kilometers. The pits probably formed when lava erupted from the side of Arsia Mons. When lava, or molten rock, finds its way to the surface, it produces several veins and chambers. These slowly empty as the lava erupts and runs down the volcano flanks. Some of the lava reaching the surface cools down and becomes solid, often building a roof over the emptied chamber. The resulting voids collapse due to the weight of the overlying material. At several places, the walls of the pits have been modified by later landslides. The overall trend of the collapse zone runs from the south-west to the north-east, following exactly a giant zone of crustal weakness in the Tharsis region, along which the three large Tharsis volcanoes are aligned. Arsia Mons is the southernmost of these volcanoes. It is 435 kilometers in diameter, almost 20 kilometers high, and the summit caldera is 116 kilometers wide.
The images that were used to create this colour composite were taken on April 2, 2004, by the High Resolution Stereo Camera (HRSC) on board ESA’s Mars Express spacecraft. The images were taken from an altitude of 400 kilometers and cover an area of about 80 by 105 kilometers.
The colour composite has not yet been officially released by ESA.
Image Credit: ESA/DLR/FU Berlin (G. Neukum)/astroarts.org
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Tyrrhena Patera
The flanks of this ancient, southern hemisphere volcano have been strongly modified and embayed. At the summit is an irregular depression that is continuous with a valley, extending down the outer flanks. Concentric graben surround the summit. The volcano is so degraded that there are no well-defined primary volcanic depositional features to provide clues regarding the nature of the erupted materials. However, the low profile of the volcano, and the way in which outliers of the volcano form mesa-like bodies, suggest ash flow deposits rather than lavas.
The summit region of Tyrrhena Patera.
This mosaic of nine Viking 1 Orbiter images (f445a48 to f445a56) of the summit region of Tyrrhena Patera, taken on September 5, 1977, shows late stage caldera filling material, ring fractures, and volcano-tectonic channels. Small mare ridges are observed within the caldera-filling material. Erosional scarps and remnant mesas are evident at the margin of the basal shield unit to the northwest of Tyrrhena Patera.
The image covers a length of approximately 250 kilometers.
Image Credit: NASA/JPL/Arizona State University/Mosaic by astroarts.org
The margin of the summit shield unit.
This high-resolution Viking 1 Orbiter image (f794a01) of the margin of the summit shield unit to the northwest of Tyrrhena Patera, taken on August 20, 1978, shows erosional scarps bounding the edge of a large volcano-tectonic channel. The morphology of the channel floor is apparently the result of mass wasting. Different levels of erosion of the summit shield suggest layering in the deposits, and faint lineations may be indicative of a drainage pattern.
The image covers a length of approximately 15 kilometers.
Image Credit: NASA/JPL/Arizona State University/astroarts.org
The north and northwestern sections of
Tyrrhena Patera.
Viking 1 Orbiter image (f480a48) of the north and northwestern sections of Tyrrhena Patera, taken on October 10, 1977. Erosional scarps and mesas are evident at the margins of the basal and summit shield units. Multiple layering is observed in the deposits, with many layers apparent to the north along the path of the northeastern volcano-tectonic channel and segments of the outer ring fracture set.
The image covers a length of approximately 200 kilometers.
Image Credit: NASA/JPL/Arizona State University/astroarts.org
The smooth plains to the west of
Tyrrhena Patera.
This Viking 1 Orbiter image (f087a12), taken on September 16, 1976, shows the surface of the smooth plains to the west of Tyrrhena Patera containing erosional scarps and mare-type ridges.
The image covers a length of approximately 140 kilometers.
Image Credit: NASA/JPL/Arizona State University/astroarts.org
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Peneus and Amphitrites Paterae
Peneus and Amphitrites Paterae
Oblique view of Peneus and Amphitrites Paterae on the southern rim of the Hellas Basin.
Peneus Patera, 100-120 km across, is slightly elongate along a northeasterly trend and bounded by a zone of concentric normal faults and grabens. The floor is marked by large wrinkle ridges; one may account for a prominent bench on the southeast side of the patera.
Amphitrites Patera, 120 km across, forms a ridge and scarp structure surrounded by a 300-km-diameter low shield dissected by narrow channels; it is bordered to the south by crater Barnard. A few wrinkle ridges radiate from Amphitrites Patera, thus diverting channels.
South and west of Peneus Patera, local sets of similarly trending and spaced wrinkle ridges crosscut one another.
Mosaic of the Viking 1 Orbiter images f094a74, f094a75 and f094a76, taken on September 22, 1976.
North is at the eight o’clock position. Image resolution is about 250 m/pixel.
Image Credit: NASA/JPL/Arizona State University/Mosaic by astroarts.org
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Ascraeus Mons caldera
The summit of Ascraeus Mons.
Ascraeus Mons is the northernmost of three shield volcanoes (known as the Tharsis Montes) near the equator of Mars. Its complex caldera (volcanic crater) is composed of several discrete centers of collapse where the older collapse features are cross-cut by more recent collapse events. The lowermost circular floor preserves the last lava flooding event that followed the last major collapse approximately 100 million years ago. The southern wall of the caldera has at least 3 km of vertical relief with an average slope of at least 26º (from horizontal). The caldera complex truncates several lava flows, indicating that the flows predate the collapse event and that their source areas have been destroyed by the caldera formation.
This image was taken by the High Resolution Stereo Camera (HRSC) on board ESA’s Mars Express spacecraft and has not yet been officially released by ESA.
Image Credit: ESA/DLR/FU Berlin (G. Neukum)/astroarts.org
The complex caldera at the summit of
Ascraeus Mons.
This vertical view shows the complex caldera at the summit of Ascraeus Mons. North is at the top.
Image Credit: ESA/DLR/FU Berlin (G. Neukum)/astroarts.org
Perspective view of the caldera at the summit of
Ascraeus Mons.
This perspective view shows the complex caldera of Ascraeus Mons.
The vertical exaggeration is 1.5. North is up.
Image Credit: ESA/DLR/FU Berlin (G. Neukum)/astroarts.org
References:
G. Neukum et al.: Recent and episodic volcanic and glacial activity on Mars revealed by the HRSC (PDF; 856 KB)