Viking Orbiter
Landslide in Valles Marineris
Landslide at the 5 km high south wall
of Ganges Chasma.
Although Valles Marineris originated as a tectonic structure, it has been modified by other processes. This image shows a close-up view of a landslide at the 5 km high south wall of Ganges Chasma.
The unnamed impact crater on the plateau, which is a part of Aurorae Planum, is approximately 27 km in diameter. The floor of the crater is smooth and flat, so it seems likely that the interior of this crater has been partly filled with basalts or with sand and dust blown by wind. The landslide partially removed the rim of the crater.
The debris apron appears to have formed by collapse of the slump blocks at the base of the wall and extends about 40 kilometers across the floor of Ganges Chasma.
The landslides in Valles Marineris generally show few meteorite impact craters, and so are quite young; they probably formed in the Amazonian Epoch of Mars’ history, some 1.8 billion years ago.
Viking 1 Orbiter image f014a30, taken on July 4, 1976.
The image covers a length of approximately 60 kilometers.
Image Credit: NASA/JPL/Arizona State University/astroarts.org
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Color mosaic of Olympus Mons
Color mosaic of the Martian Olympus Mons volcano
and its surrounding plains.
Mosaic of the Martian Olympus Mons volcano and its surrounding plains made from two color composites using the following Viking 1 Orbiter images:
f735a41 and f735a42 (violet), f735a45 and f735a46 (green), f735a47 and f735a48 (red).
These images were taken on June 22, 1978.
The mosaic covers an area of nearly 1,600 x 800 kilometers. North is right and west is up.
Image Credit: NASA/JPL/Arizona State University/Mosaic by astroarts.org
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Argyre Basin
Oblique view of the Argyre Basin.
This is a mosaic of the Viking 1 Orbiter images f022a94 (taken on July 12, 1976), f034a11 to 16 and f034a34 (taken on July 24, 1976), and f040a04 (taken on July 30, 1976) and shows the Argyre impact basin in the southern highlands of Mars.
The basin, which is approximately 1,300 kilometers in diameter, was formed about 4 billion years ago during the Heavy Bombardment Period of the early Solar System when an asteroid or comet roughly 50 kilometers across impacted Mars.
Argyre is believed to be the second-largest impact basin on Mars after Hellas Planitia and may be one of the best preserved ancient impact basins from the Heavy Bombardment Period.
Argyre is surrounded by rugged massifs which form concentric and radial patterns around the basin. Several mountain ranges are present, including Charitum and Nereidum Montes.
The 230 km wide Galle Crater, located on the eastern rim of Argyre, strongly resembles a smiley face.
Above the horizon are detached layers of haze 25 to 40 km high, thought to be crystals of carbon dioxide.
Image Credit: NASA/JPL/Arizona State University/Mosaic by astroarts.org
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White Rock in Pollack Crater
"White Rock" on the floor of Pollack Crater.
This mosaic of the Viking 1 Orbiter images f826a33 to 38, taken on September 21, 1978, shows the feature colloquially called “White Rock” which is located on the floor of Pollack Crater in the Sinus Sabaeus region near the Martian equator.
The mosaic was rotated to put north up.
Image Credit: NASA/JPL/Arizona State University/Mosaic by astroarts.org
White Rock got its nickname more than 30 years ago, when scientists first spotted the feature on the floor of Pollack Crater in images taken by the Mariner 9 spacecraft.
Pollack, which is about 90 kilometers wide, has a dark floor, especially over its southern half, where White Rock lies. At the time of Mariner 9, rather contrasty image processing gave White Rock, which measures about 15 by 18 km, a chalky-bright appearance.
This brightness led many scientists to propose White Rock was made of water-deposited sediments, like the salty residue of a dried-up desert lake.
In 2001, however, scientists working with the Thermal Emission Spectrometer (TES) on NASA’s Mars Global Surveyor (MGS) found that White Rock has a dry origin and is built of wind-blown sediments. The bright blocks and ridges have the same brightness as light-colored, dusty regions elsewhere on Mars, and White Rock’s spectra likewise matches these and shows no trace of water.
The wind-sculpted ridges that make up White Rock rise about 300 meters above Pollack Crater’s floor, which shows as dark lanes cutting into the light-colored formation.
While the light material stands up as buttes and ridges, lots of loose material nonetheless surrounds White Rock. At the feature’s northern end lies a field of dunes made of dark, basaltic sand grains. These sand grains probably eroded from the lava that covers the floor of Pollack. The dune shapes suggest that some winds blew from the east or southeast. It is possible these were funneled by the channel, some 500 meters wide, that cuts straight through White Rock.
See also:
“White Rock” of Pollack Crater – MGS MOC Release No. MOC2-264, 4 December 2000
HiRISE – White Rock Feature in Pollack Crater (PSP_002099_1720)
HiRISE – White Rock Landform in Pollack Crater (PSP_002244_1720)
CRISM – Pollack Crater’s White Rock
offOlympus Mons caldera
Viking Orbiter image mosaic
of the Olympus Mons caldera.
This mosaic of 22 Viking 1 Orbiter images (f473s13/17/19/21/23/25/27/29, f474s17/19, and f474s21 to 32), taken on July 11 and July 12, 1980, shows the complex caldera at the summit of Olympus Mons. South is at the top.
The caldera, a composite of as many as seven roughly circular collapse depressions, is 66 by 83 km across. The lowest parts of the floor are over 4 kilometers below the rim of the caldera.
Image Credit: NASA/JPL/Arizona State University/Mosaic by astroarts.org
Note: This is the most complete high-resolution Viking Orbiter image mosaic of the Olympus Mons caldera which has been published to date.
For comparison, here is a mosaic of the Olympus Mons caldera produced by A. Tayfun Öner in 1997 and published on Calvin J. Hamilton’s website “Views of the Solar System”, and here is a mosaic produced by JPL and published in NASA’s Planetary Photojournal.