Image of the Oxia Palus Quadrangle (MC-11). The region contains heavily cratered highlands in the southeast which are intersected by several large outflow channels terminating in the relatively smooth plains of Chryse basin in the northwest.
Many craters within Oxia Palus are named after famous scientists. Besides Galilei and da Vinci, some of the people who discovered the atom and radiation are honored there: Curie, Becquerel, and Rutherford.[2]
Mawrth Vallis was strongly considered as a landing site for NASA's Curiosity rover, the Mars Science Laboratory.[3] It made it to at least the top two sites for NASA's EXoMars 2020 Rover mission. The exact location proposed for this landing is 22.16 N and 342.05 E.[4]
The Mawrth Vallis region is well studied with more than 40 papers published in peer-reviewed publications. Near the Mawrth channel is a 200 meter high plateau with many exposed layers. Spectral studies have detected clay minerals that present as a sequence of layers.[5][6][7][8][9][10][11][12][13][14][15] Clay minerals were probably deposited in the Early to Middle Noachian period. Later weathering exposed a variety of minerals such as kaolin, alunite, and jarosite. Later, volcanic material covered the region. This volcanic material would have protected any possible organic materials from radiation.[16]
Another site in the Oxia Palus quadrangle has been picked for the EXoMars 2020 landing is at 18.14 N and 335.76 E. This site is of interest because of a long-duration aqueous system including a delta, possible biosignatures, and a variety of clays.[4][17][18]
This quadrangle contains abundant evidence for past water in such forms as river valleys, lakes, springs, and chaos areas where water flowed out of the ground. A variety of clay minerals have been found in Oxia Palus. Clay is formed in water, and it is good for preserving microscopic evidence of ancient life.[19] Recently, scientists have found strong evidence for a lake located in the Oxia Palus quadrangle that received drainage from Shalbatana Vallis. The study, carried out with HiRISE images, indicates that water formed a 30-mile-long canyon that opened up into a valley, deposited sediment, and created a delta. This delta and others around the basin imply the existence of a large, long-lived lake. Of special interest is evidence that the lake formed after the warm, wet period was thought to have ended. So, lakes may have been around much longer than previously thought. [20][21] In October 2015, Oxia Planum, a plain located near 18°16′30″N335°22′05″E / 18.275°N 335.368°E / 18.275; 335.368,[22] was reported to be the preferred landing location for the ExoMarsrover.[23][24] An erosion-resistant layer on top of clay units may have preserved evidence of life.[25][26]
Surface appearance
The Mars Pathfinder found its landing site to contain a great deal of rocks. Analysis shows the area to have a greater density of rocks than 90% of Mars. Some of the rocks leaned against each other in a manner geologists term imbricated. It is believed strong flood waters in the past pushed the rocks around to face away from the flow. Some pebbles were rounded, perhaps from being tumbled in a stream. Some rocks have holes on their surfaces that seem to have been fluted by wind action. Small sand dunes are present. Parts of the ground are crusty, maybe due to cementing by a fluid containing minerals. In general the rocks show a dark gray color with patches of red dust or weathered appearance on their surfaces. Dust covers the lower 5–7cm of some rocks, so they may have once been buried, but have now become exhumed. Three knobs, one large crater, and two small craters were visible on the horizon.[27]
Types of rocks
Results of Mars Pathfinder's Alpha Proton X-ray Spectrometer indicated that some rocks in the Oxia Palus quadrangle are like Earth's andesites. The discovery of andesites shows that some Martian rocks have been remelted and reprocessed. On Earth, Andesite forms when magma sits in pockets of rock while some of the iron and magnesium settle out. Consequently, the final rock contains less iron and magnesium and more silica. Volcanic rocks are usually classified by comparing the relative amount of alkalis (Na2O and K2O) with the amount of silica (SiO2). Andesite is different from the rocks found in meteorites that have come from Mars.[27][28][29]
By the time that final results of the mission were described in a series of articles in the journal Science (December 5, 1997), it was believed that the rock Yogi contained a coating of dust, but was similar to the rock Barnacle Bill. Calculations suggest that the two rocks contain mostly the minerals orthopyroxene (magnesium-iron silicate), feldspars (aluminum silicates of potassium, sodium, and calcium), quartz (silicon dioxide), with smaller amounts of magnetite, ilmenite, iron sulfide, and calcium phosphate.[27][28][29]
Map of Oxia Palus labeled with major features
View from Mars Pathfinder
The Sojourner Rover is taking its Alpha Proton X-ray Spectrometer measurement of the Yogi Rock (NASA). Note: Sojourner Rover was the rover part of the Mars Pathfinder. It rolled off of the lander. This picture was taken by the lander.
Other results from Pathfinder
By taking multiple images of the sky at different distances from the sun, scientists were able to determine that size of the particles in the pink haze was about 1 micrometer in radius. The color of some soils was similar to that of an iron oxyhydroxide phase which would support a warmer and wetter climate in the past.[30] Pathfinder carried a series of magnets to examine the magnetic component of the dust. Eventually, all but one of the magnets developed a coating of dust. Since the weakest magnet did not attract any soil, it was concluded that the airborne dust did not contain pure magnetite or one type of maghemite. The dust probably was an aggregate possible cemented with ferric oxide (Fe2O3).[31]
Winds were usually less than 10m/s. Dust devils were detected in the early afternoon. The sky had a pink color. There was evidence of clouds and maybe fog.[27]
River valleys and chaos
Many large, ancient river valleys are found in this area; along with collapsed features, called Chaos. The Chaotic features may have collapsed when water came out of the surface. Martian rivers begin with a Chaos region. A chaotic region can be recognized by a rat's nest of mesas, buttes, and hills, chopped through with valleys which in places look almost patterned. Some parts of this chaotic area have not collapsed completely—they are still formed into large mesas, so they may still contain water ice.[32] Chaotic terrain occurs in numerous locations on Mars, and always gives the strong impression that something abruptly disturbed the ground. More information and more examples of chaos can be found at Chaos terrain. Chaos regions formed long ago. By counting craters (more craters in any given area means an older surface) and by studying the valleys' relations with other geological features, scientists have concluded the channels formed 2.0 to 3.8 billion years ago.[33]
One generally accepted view for the formation of large outflow channels is that they were formed by catastrophic floods of water released from giant groundwater reservoirs. Perhaps, the water started to come out of the ground due to faulting or volcanic activity. Sometimes hot magma just travels under the surface. If that is the case, the ground will be heated, but there may be no evidence of lava at the surface. After water escapes, the surface collapses. Moving across the surface, the water would have simultaneously frozen and evaporated. Chunks of ice that would have rapidly formed may have enhanced the erosive power of the flood. Furthermore, the water may have frozen over at the surface, but continuing to flow underneath, eroding the ground as it moved along. Rivers in cold climates on the Earth often become ice-covered, yet continue to flow.
Research, published in January 2010, suggests that Mars had lakes, each around 20km wide, along parts of the equator, in the Oxia Palus quadrangle. Although earlier research showed that Mars had a warm and wet early history that has long since dried up, these lakes existed in the Hesperian Epoch, a much earlier period. Using detailed images from NASA's Mars Reconnaissance Orbiter, the researchers speculate that there may have been increased volcanic activity, meteorite impacts, or shifts in Mars' orbit during this period to warm Mars' atmosphere enough to melt the abundant ice present in the ground. Volcanoes would have released gases that thickened the atmosphere for a temporary period, trapping more sunlight and making it warm enough for liquid water to exist. In this new study, channels were discovered that connected lake basins near Ares Vallis. When one lake filled up, its waters overflowed the banks and carved the channels to a lower area where another lake formed.[35][36] These lakes would be another place to look for evidence of present or past life.
Aram Chaos
Aram Chaos is an ancient impact crater near the Martian equator, close to Ares Vallis. About 280 kilometers (170mi) across, Aram lies in a region called Margaritifer Terra, where many water-carved channels show that floods poured out of the highlands onto the northern lowlands ages ago. The Thermal Emission Imaging System (THEMIS) on the Mars Odyssey orbiter found gray crystalline hematite on the floor of Aram. Hematite is an iron-oxide mineral that can precipitate when ground water circulates through iron-rich rocks, whether at normal temperatures or in hot springs. The floor of Aram contains huge blocks of collapsed, or chaotic, terrain that formed when water or ice was catastrophically removed. Elsewhere on Mars, the release of groundwater produced massive floods that eroded the large channels seen in Ares Vallis and similar outflow valleys. In Aram Chaos, however, the released water stayed mostly within the crater's ramparts, eroding only a small, shallow outlet channel in the eastern wall. Several minerals including hematite, sulfate minerals, and water-altered silicates in Aram suggests that a lake probably once existed within the crater. Because forming hematite requires liquid water, which could not long exist without a thick atmosphere, Mars must have had a much thicker atmosphere at some time in the past, when the hematite was formed.[37]
Blocks in Aram showing possible source of water, as seen by THEMIS
Hanging valleys in Aram Chaos, as seen by HiRISE under HiWish program
Wide view of Aram Chaos, as seen by HiRISE under the HiWish program. The black strip is where data was not gathered.
Aram Chaos with a light toned mound as seen by HiRISE under the HiWish program. The mound probably contains water bearing minerals.
Light toned mound as seen by HiRISE under the HiWish program. The mound probably contains water bearing minerals.
Layered sediments
Oxia Palus is an interesting area with many craters showing layered sediments.[38] Such sediments may have been deposited by water, wind, or volcanoes. The thickness of the layers is different in different craters. In Becquerel many layers are about 4 meters thick. In Crommelin crater the layers average 20 meters in thickness. At times, the top layer may be resistant to erosion and will form a feature called a mensa, the Latin word for table.[39]
The pattern of layers within layers measured in Becquerel crater suggests that each layer was formed over a period of about 100,000 years. Moreover, every 10 layers can be grouped into larger bundles. So every 10-layer pattern took one million years to form (100,000 years/layer × 10 layers). The ten-layer pattern is repeated at least ten times, that is there are least ten bundles, each consisting of ten layers. It is believed that the layers relate to the cycle of changing tilt of Mars.
The tilt of the Earth's axis changes by only a little more than 2 degrees. In contrast, Mars's tilt varies by tens of degrees. Today, the tilt (or obliquity) of Mars is low, so the poles are the coldest places on the planet, while the equator is the warmest. This causes gases in the atmosphere, like water and carbon dioxide, to migrate poleward, where they turn into ice. When the obliquity is higher, the poles receive more sunlight, and those materials migrate away. When carbon dioxide moves from the poles, the atmospheric pressure increases, maybe causing a difference in the ability of winds to transport and deposit sand. With more water in the atmosphere, sand grains deposited on the surface may stick and cement together to form layers. This study was done using stereo topographic maps obtained by processing data from the high-resolution camera onboard NASA's Mars Reconnaissance Orbiter.[40]
A detailed discussion of layering with many Martian examples can be found in Sedimentary Geology of Mars.[41]
Buttes, as seen by HiRISE under HiWish program. Buttes have layered rocks with a hard resistant cap rock on the top which protects the underlying rocks from erosion.
Becquerel layers, as seen by HiRISE. Click on image to see fault.
Mounds in craters showing layers are formed by the erosion of layers that were deposited after the impact.
Punsk Crater, as seen by HiRISE. Scale bar is 500 meters long. Click on image to see possible fine layers on floor. Image on right is an enlargement of south (bottom) wall of crater.
Hydraotes Chaos, as seen by HiRISE. Click on image to see channels and layers. Scale bar is 1000 meters long.
Grindavik Crater, as seen by HiRISE. Scale bar is 1000 meters long.
Layers in Monument Valley. These are accepted as being formed, at least in part, by water deposition. Since Mars contains similar layers, water remains as a major cause of layering on Mars.
Close-up of one of the mesas in previous photo showing layers. Mesa may be the remains of a lake in which sediments were deposited. Picture obtained with HiRISE, under HiWish program.
Wide view of layers, as seen by HiRISE under HiWish program
Close view of layers, as seen by HiRISE under HiWish program
Wide view of layered features, as seen by HiRISE under HiWish program
Close view of layered features, as seen by HiRISE under HiWish program
Wide view of layered features and ridges, as seen by HiRISE under HiWish program
Close view of layers, as seen by HiRISE under HiWish program
Close view of layers, as seen by HiRISE under HiWish program
Close view of layers, as seen by HiRISE under HiWish program
Close view of layers in a mound, as seen by HiRISE under HiWish program
Close view of layers, as seen by HiRISE under HiWish program
Small sets of layers in Aram Chaos, as seen by HiRISE under HiWish program
Layers and yardangs, as seen by HiRISE under HiWish program. Arrows point to some yardangs.
Wide view of layers in a depression near Shalbatana Vallis, as seen by HiRISE under HiWish program
Close view of layers in a depression near Shalbatana Vallis, as seen by HiRISE under HiWish program
Close view of layers in a depression near Shalbatana Vallis, as seen by HiRISE under HiWish program
Wide view of layers, as seen by HiRISE under HiWish program
Close view of layers, as seen by HiRISE under HiWish program
Close view of layers, as seen by HiRISE under HiWish program. Box shows size of football field.
Close view of layers, as seen by HiRISE under HiWish program
Close view of layers, as seen by HiRISE under HiWish program. A fault is visible.
Close view of layers, as seen by HiRISE under HiWish program
Close view of layers, as seen by HiRISE under HiWish program
Layers, as seen by HiRISE under HiWish program
Wide view of various shapes created by erosion, as seen by HiRISE under HiWish program
Close color view of layered mesa and mound, as seen by HiRISE
Close view of edge of layered mesa, as seen by HiRISE
Close view of layered mesa with pyramid shapes, as seen by HiRISE under HiWish program
Wide view of layers in Danielson Crater, as seen by HiRISE under HiWish program
Close view of top of image of Danielson Crater, as seen by HiRISE (ESP_071634_1880)
Close view of top of image of Danielson. Arrows indicate parts that are enlarged.
Layers in Danielson Crater with enlargements of some spots (indicated with arrows)
Layers in Danielson Crater with enlargements of some spots (indicated with arrows)
Layers in Danielson Crater, as seen by HiRISE under HiWish program
Layers in Danielson Crater, as seen by HiRISE under HiWish program
Linear ridge networks
Linear ridge networks are found in various places on Mars in and around craters.[42] Ridges often appear as mostly straight segments that intersect in a lattice-like manner. They are hundreds of meters long, tens of meters high, and several meters wide. It is thought that impacts created fractures in the surface, these fractures later acted as channels for fluids. Fluids cemented the structures. With the passage of time, surrounding material was eroded away, thereby leaving hard ridges behind. Since the ridges occur in locations with clay, these formations could serve as a marker for clay which requires water for its formation.[43][44][45] Water here could have supported past life in these locations. Clay may also preserve fossils or other traces of past life.
Possible dikes and layered structures, as seen by HiRISE under HiWish program. These may be part of linear ridge networks that are produced with impact craters.
Possible fault along a butte, as seen by HiRISE under HiWish program. These may be part of linear ridge networks that are produced with impact craters.
Layers and ridge networks, as seen by HiRISE under HiWish program
Layers in a mound and ridge networks, as seen by HiRISE under HiWish program
Ridge networks of various sizes, as seen by HiRISE under HiWish program
Ridge networks, as seen by HiRISE under HiWish program
Many areas of Mars show wrinkles on the surface, called wrinkle ridges. They are elongated and are often found on smooth area of Mars. Because they are wide, gentle topographic highs, they are sometimes hard to see. Although first thought to be caused by lava flows, they are now generally thought to be more likely caused by compressional tectonic forces that cause folding and faulting. A wrinkle ridge is visible in the image to the right of Ares Vallis.[46]
A picture below right, taken of layers in Becquerel Crater, shows a straight line that represents a fault.[47] Faults are breaks in rocks where movement has taken place. The movement may be only inches or much more. Faults can be very significant, as the break in the rock is a focus for erosion and, more importantly, can allow fluids containing dissolved minerals to rise, then be deposited. Some of the major ore deposits on Earth are formed by this process.
Faults in Danielson Crater, as seen by HiRISE under HiWish program
Faults and layers in Danielson Crater, as seen by HiRISE under HiWish program
Springs
A study of images taken with the High Resolution Imaging Science Experiment (HiRISE) on the Mars Reconnaissance Orbiter strongly suggests that hot springs once existed in Vernal Crater, in the Oxia Palus quadrangle. These springs may have provided a long-time location for life. Furthermore, mineral deposits associated with these springs may have preserved traces of Martian life. In Vernal Crater on a dark part of the floor, two light-toned, elliptical structures closely resemble hot springs on the Earth. They have inner and outer halos, with roughly circular depressions. A large number of hills are lined up close to the springs. These are thought to have formed by the movement of fluids along the boundaries of dipping beds. A picture below shows these springs. One of the depressions is visible. The discovery of opaline silica by the Mars Rovers, on the surface also suggests the presence of hot springs. Opaline silica is often deposited in hot springs.[48] Scientists proposed this area should be visited by the Mars Science Laboratory.[49]
The crater Mojave, in the Xanthe Terra region, has alluvial fans that look remarkably similar to landforms in the Mojave Desert in the American southwest. As on Earth, the largest rocks are near the mouths of the fans. Because channels start at the tops of ridges, it is believed they were formed by heavy downpours. Researchers have suggested that the rain may have been initiated by impacts.[50]
Mojave is approximately 2,604 meters (1.618 miles) deep. Its depth relative to its diameter and its ray system are indications it is very young. Crater counts of its ejecta blanket give an age of about 3 million years. It is considered the most recent crater of its size on Mars, and has been identified as the probable source of the shergottite meteorites collected on Earth.[51]
Alluvial Fans in Mojave, as seen by HiRISE. The crater rim is on the right. A branched network of channels runs down towards the left.
Another view of Mojave from HiRISE (north is at bottom)
Firsoff Crater
MOLA map showing Firsoff Crater and other nearby craters. Colors indicate elevations.
Layers in Firsoff Crater, as seen by HiRISE
Close-up of layers in Firsoff Crater, as seen by HiRISE Note: this is an enlargement of the previous image of Firsoff Crater.
Top part of previous images, as seen by HiRISE. Note: dark parts are basalt sand.
Fault across layers in a mesa in Firsoff Crater, as seen by HiRISE under HiWish program
Close-up of layers in Firsoff Crater, as seen by HiRISE under HiWish program
Wide view of layered surface in Firsoff Crater, as seen by HiRISE under HiWish program
Layers in Firsoff crater with a box showing the size of a football field. Picture taken by HiRISE under HiWish program.
Layers and faults in Firsoff Crater, as seen by HiRISE under HiWish program. Arrows show one large fault, but there are other smaller ones in the picture.
Layered mound, as seen by HiRISE under HiWish program. The white box represents the size of a football field for scale.
Crommelin crater showing layers and dust devil tracks, as seen by CTX camera (on Mars Reconnaissance Orbiter). Note: this is an enlargement of a previous image of Crommelin crater.
Crommelin crater showing layers arranged in the shape of ovals, as seen by CTX camera (on Mars Reconnaissance Orbiter). Note: this is an enlargement of a previous image of Crommelin crater.
Crommelin crater showing layers in buttes and inside a small crater, as seen by CTX camera (on Mars Reconnaissance Orbiter). Note: this is an enlargement of a previous image of Crommelin crater.
Crommelin crater, showing layers, as seen by HiRISE
Butte in Crommelin (Martian crater), as seen by HiRISE under HiWish program. Location is Oxia Palus quadrangle.
Layers in Crommelin Crater, as seen by HiRISE under HiWish program. Location is Oxia Palus quadrangle.
Layers in Crommelin Crater, as seen by HiRISE under HiWish program Arrow indicates fault. Location is Oxia Palus quadrangle.
Crommelin Crater Layered Deposit, as seen by HiRISE. The color blue in the photo is a false color.
Wide view of layers in Crommelin crater, as seen by HiRISE under HiWish program. Parts of this photo are enlarged in following images.
Close view of layered mound in Crommelin crater, as seen by HiRISE under HiWish program. Box indicates the size of a football field for scale.
Close view of layers in Crommelin crater, as seen by HiRISE under HiWish program
Close view of layers in Crommelin crater, as seen by HiRISE under HiWish program
Close view of layers in Crommelin crater, as seen by HiRISE under HiWish program. Arrow points to a fault.
Close view of layers in Crommelin crater, as seen by HiRISE under HiWish program
Close view of layers in Crommelin crater, as seen by HiRISE under HiWish program. Arrow points to a fault.
Some of the layers of Danielson Crater is just visible in this CTX image. Dunes are also visible.
Many layers are visible in this HiRISE image of Danielson Crater. Dark dust serves to highlight some of the layers.
Wide-view of layers in Danielson Crater, as seen by HiRISE under HiWish program. Box shows location of next image. Dark parts of image are dark, basalt sand sitting on level places.
Enlargement of previous image of Danielson Crater showing a fault and layers. Image taken with HiRISE, under HiWish program.
Wide view of part of Danielson Crater, as seen by HiRISE under HiWish program
Enlargement of previous image of Danielson Crater, as seen by HiRISE under HiWish program. The box represents the size of a football field.
Close up of layers in Danielson Crater, as seen by HiRISE under HiWish program—boulders are visible, as well as dark sand
Layers in Danielson Crater with dust devil tracks at the top of the picture, as seen by HiRISE under HiWish program
Wide view of layers in Danielson Crater, as seen by HiRISE under HiWish program
Wide view of layers in Danielson Crater, as seen by HiRISE under HiWish program. Center color band of the HiRISE image is visible.
Layers in Danielson Crater, as seen by HiRISE under HiWish program. Scale is shown.
Layers and dark dust in Danielson Crater, as seen by HiRISE under HiWish program
Layers and dark dust in Danielson Crater, as seen by HiRISE under HiWish program
Layers, crater, and mounds on floor of Danielson Crater, as seen by HiRISE under HiWish program
Close view of crater on floor of Danielson Crater, as seen by HiRISE under HiWish program
Layered mound on floor of Danielson Crater, as seen by HiRISE under HiWish program
Close, color view of layers and dark dust on floor of Danielson Crater, as seen by HiRISE under HiWish program
Close, color view of layers and dark dust on floor of Danielson Crater, as seen by HiRISE under HiWish program. Boulders are visible in the image.
Close, color view of layers and dark dust on floor of Danielson Crater, as seen by HiRISE under HiWish program. Faults are indicated with arrows.
Close view of layers on floor of Danielson Crater, as seen by HiRISE under HiWish program. Some faults are visible in image.
Close, color view of layers and dark dust on floor of Danielson Crater, as seen by HiRISE under HiWish program. Some small faults are visible in image.
A pedestal crater is a crater with its ejecta sitting above the surrounding terrain and thereby forming a raised platform (like a pedestal). They form when an impact crater ejects material which forms an erosion-resistant layer, thus causing the immediate area to erode more slowly than the rest of the region. Some pedestals have been accurately measured to be hundreds of meters above the surrounding area. This means that hundreds of meters of material were eroded away. The result is that both the crater and its ejecta blanket stand above the surroundings. Pedestal craters were first observed during the Mariner missions.[52][53][54][55]
Pedestal Crater and ridge in Oxia Palus quadrangle, as seen by HiRISE. Click on image to see detail of the edge of the pedestal crater. The flat-topped ridge near the top of the image was once a river that became inverted. The pedestal crater superposes the ridge, so it is younger.
Pedestal craters form when the ejecta from impacts protect the underlying material from erosion. As a result of this process, craters appear perched above their surroundings.
Drawing shows a later idea of how some pedestal craters form. In this way of thinking, an impacting projectile goes into an ice-rich layer—but no further. Heat and wind from the impact hardens the surface against erosion. This hardening can be accomplished by the melting of ice which produces a salt/mineral solution thereby cementing the surface.
Wide CTX image of layers under the ejecta surface of a pedestal crater
Layers under top layer of pedestal crater, as seen by HiRISE under HiWish program
Close view of layers under ejecta surface of pedestal crater, as seen by HiRISE under HiWish program
Close view of layers under ejecta surface of pedestal crater, as seen by HiRISE under HiWish program
Other craters
Impact craters generally have rims with ejecta around them; in contrast volcanic craters usually do not have a rim or ejecta deposits. As craters get larger (greater than 10km in diameter) they usually have a central peak.[56] The peak is caused by a rebound of the crater floor following the impact.[46] Sometimes craters display layers. Since the collision that produces a crater is like a powerful explosion, rocks from deep underground are tossed onto the surface. Hence, craters can show what lies deep under the surface.
Marth Crater, as seen by CTX camera (on Mars Reconnaissance Orbiter).
Marth Crater showing dunes, as seen by CTX camera (on Mars Reconnaissance Orbiter). Note: this is an enlargement of the previous image of Marth Crater.
Ejecta margin of unnamed crater, as seen by HiRISE under HiWish program
Eroded craters, as seen by HiRISE. One crater is half eroded away. Another crater has eroded to form a tall, thin rim, and its ejecta has been eroded away. This image is part of an image that was named HiRISE picture of the day.
One crater here has a depression on its floor. This may be due to the impacting body going down to a softer material.
Vallis was used for old river valleys that were discovered on Mars, when probes were first sent to Mars. The Viking Orbiters caused a revolution in our[who?] ideas about water on Mars; huge river valleys were found in many areas. Spacecraft cameras showed that floods of water broke through dams, carved deep valleys, eroded grooves into bedrock, and traveled thousands of kilometers.[46][57][58]
Shalbatana Vallis, as seen by HiRISE. The scale bar is 500 meters long.
Shalbatana Vallis Floor, as seen by HiRISE. Scale bar is 1000 meters long.
Ares Vallis, as seen by Viking. The channel is 25km wide and about 1km deep.
Channels in Ares Vallis Region, as seen by HiRISE
Ares Valles, as seen by HiRISE
Tiu Valles Ridges, as seen by HiRISE. Ridges were probably formed by running water. Scale bar is 1km long.
Teardrop-shaped islands caused by flood waters from Maja Valles, as seen by Viking Orbiter. Image is located in Oxia Palus quadrangle. The islands are formed in the ejecta of Lod Crater, Bok Crater, and Gold Crater.
Valley, as seen by HiRISE under HiWish program
Hanging valleys in Aram Chaos, as seen by HiRISE under HiWish program
The Memnonia quadrangle is one of a series of 30 quadrangle maps of Mars used by the United States Geological Survey (USGS) Astrogeology Research Program. The Memnonia quadrangle is also referred to as MC-16.
Margaritifer Terra is an ancient, heavily cratered region of Mars. It is centered just south of the Martian equator at 4.9°S 25°W and covers 2600 km at its widest extent. The area reveals "chaos terrain", outflow channels, and alluvial plains that are indicative of massive flooding. Wind erosion patterns are also in evidence. A region within the terra shows some of the highest valley network densities on the planet. Ares Vallis is another notable feature, where the flood and flow patterns are in evidence; it was the landing site of the Soviet Mars 6 lander and NASA's Mars Pathfinder. It is also one of several proposed landing sites for the Mars 2020 Rover.
The Ismenius Lacus quadrangle is one of a series of 30 quadrangle maps of Mars used by the United States Geological Survey (USGS) Astrogeology Research Program. The quadrangle is located in the northwestern portion of Mars' eastern hemisphere and covers 0° to 60° east longitude and 30° to 65° north latitude. The quadrangle uses a Lambert conformal conic projection at a nominal scale of 1:5,000,000 (1:5M). The Ismenius Lacus quadrangle is also referred to as MC-5. The southern and northern borders of the Ismenius Lacus quadrangle are approximately 3,065 km (1,905 mi) and 1,500 km (930 mi) wide, respectively. The north-to-south distance is about 2,050 km (1,270 mi). The quadrangle covers an approximate area of 4.9 million square km, or a little over 3% of Mars' surface area. The Ismenius Lacus quadrangle contains parts of Acidalia Planitia, Arabia Terra, Vastitas Borealis, and Terra Sabaea.
The Casius quadrangle is one of a series of 30 quadrangle maps of Mars used by the United States Geological Survey (USGS) Astrogeology Research Program. The quadrangle is located in the north-central portion of Mars' eastern hemisphere and covers 60° to 120° east longitude and 30° to 65° north latitude. The quadrangle uses a Lambert conformal conic projection at a nominal scale of 1:5,000,000 (1:5M). The Casius quadrangle is also referred to as MC-6. Casius quadrangle contains part of Utopia Planitia and a small part of Terra Sabaea. The southern and northern borders of the Casius quadrangle are approximately 3,065 km and 1,500 km wide, respectively. The north to south distance is about 2,050 km. The quadrangle covers an approximate area of 4.9 million square km, or a little over 3% of Mars' surface area.
The Cebrenia quadrangle is one of a series of 30 quadrangle maps of Mars used by the United States Geological Survey (USGS) Astrogeology Research Program. The quadrangle is located in the northeastern portion of Mars' eastern hemisphere and covers 120° to 180° east longitude and 30° to 65° north latitude. The quadrangle uses a Lambert conformal conic projection at a nominal scale of 1:5,000,000 (1:5M). The Cebrenia quadrangle is also referred to as MC-7. It includes part of Utopia Planitia and Arcadia Planitia. The southern and northern borders of the Cebrenia quadrangle are approximately 3,065 km (1,905 mi) and 1,500 km (930 mi) wide, respectively. The north to south distance is about 2,050 km (1,270 mi). The quadrangle covers an approximate area of 4.9 million square km, or a little over 3% of Mars' surface area.
The Arabia quadrangle is one of a series of 30 quadrangle maps of Mars used by the United States Geological Survey (USGS) Astrogeology Research Program. The Arabia quadrangle is also referred to as MC-12.
The Amenthes quadrangle is one of a series of 30 quadrangle maps of Mars used by the United States Geological Survey (USGS) Astrogeology Research Program. The Amenthes quadrangle is also referred to as MC-14. The quadrangle covers the area from 225° to 270° west longitude and from 0° to 30° north latitude on Mars. Amenthes quadrangle contains parts of Utopia Planitia, Isidis Planitia, Terra Cimmeria, and Tyrrhena Terra.
The Lunae Palus quadrangle is one of a series of 30 quadrangle maps of Mars used by the United States Geological Survey (USGS) Astrogeology Research Program. The quadrangle is also referred to as MC-10. Lunae Planum and parts of Xanthe Terra and Chryse Planitia are found in the Lunae Palus quadrangle. The Lunae Palus quadrangle contains many ancient river valleys.
The Sinus Sabaeus quadrangle is one of a series of 30 quadrangle maps of Mars used by the United States Geological Survey (USGS) Astrogeology Research Program. It is also referred to as MC-20 . The Sinus Sabaeus quadrangle covers the area from 315° to 360° west longitude and 0° to 30° degrees south latitude on Mars. It contains Schiaparelli, a large, easily visible crater that sits close to the equator. The Sinus Sabaeus quadrangle contains parts of Noachis Terra and Terra Sabaea.
The Iapygia quadrangle is one of a series of 30 quadrangle maps of Mars used by the United States Geological Survey (USGS) Astrogeology Research Program. The Iapygia quadrangle is also referred to as MC-21. It was named after the heel of the boot of Italy. That name was given by the Greeks It is part of a region of Italy named Apulia. The name Iapygia was approved in 1958.
The Mare Tyrrhenum quadrangle is one of a series of 30 quadrangle maps of Mars used by the United States Geological Survey (USGS) Astrogeology Research Program. This quadrangle is also referred to as MC-22. It contains parts of the regions Tyrrhena Terra, Hesperia Planum, and Terra Cimmeria.
The Margaritifer Sinus quadrangle is one of a series of 30 quadrangle maps of Mars used by the United States Geological Survey (USGS) Astrogeology Research Program. The Margaritifer Sinus quadrangle is also referred to as MC-19. The Margaritifer Sinus quadrangle covers the area from 0° to 45° west longitude and 0° to 30° south latitude on Mars. Margaritifer Sinus quadrangle contains Margaritifer Terra and parts of Xanthe Terra, Noachis Terra, Arabia Terra, and Meridiani Planum.
The Hellas quadrangle is one of a series of 30 quadrangle maps of Mars used by the United States Geological Survey (USGS) Astrogeology Research Program. The Hellas quadrangle is also referred to as MC-28 . The Hellas quadrangle covers the area from 240° to 300° west longitude and 30° to 65° south latitude on the planet Mars. Within the Hellas quadrangle lies the classic features Hellas Planitia and Promethei Terra. Many interesting and mysterious features have been discovered in the Hellas quadrangle, including the giant river valleys Dao Vallis, Niger Vallis, Harmakhis, and Reull Vallis—all of which may have contributed water to a lake in the Hellas basin in the distant past. Many places in the Hellas quadrangle show signs of ice in the ground, especially places with glacier-like flow features.
HiWish is a program created by NASA so that anyone can suggest a place for the HiRISE camera on the Mars Reconnaissance Orbiter to photograph. It was started in January 2010. In the first few months of the program 3000 people signed up to use HiRISE. The first images were released in April 2010. Over 12,000 suggestions were made by the public; suggestions were made for targets in each of the 30 quadrangles of Mars. Selected images released were used for three talks at the 16th Annual International Mars Society Convention. Below are some of the over 4,224 images that have been released from the HiWish program as of March 2016.
Chaos terrain on Mars is distinctive; nothing on Earth compares to it. Chaos terrain generally consists of irregular groups of large blocks, some tens of kilometers across and a hundred or more meters high. The tilted and flat topped blocks form depressions hundreds of metres deep. A chaotic region can be recognized by a rat's nest of mesas, buttes, and hills, chopped through with valleys which in places look almost patterned. Some parts of this chaotic area have not collapsed completely—they are still formed into large mesas, so they may still contain water ice. Chaos regions formed long ago. By counting craters and by studying the valleys' relations with other geological features, scientists have concluded the channels formed 2.0 to 3.8 billion years ago.
The common surface features of Mars include dark slope streaks, dust devil tracks, sand dunes, Medusae Fossae Formation, fretted terrain, layers, gullies, glaciers, scalloped topography, chaos terrain, possible ancient rivers, pedestal craters, brain terrain, and ring mold craters.
Danielson is an impact crater in the Oxia Palus quadrangle on Mars at 7.93° N and 7.11° W. and is 66.7 km in diameter, and is north of the Meridiani Planum, south of Arabia Terra. Its name was approved in 2009, and it was named after American engineer G. Edward Danielson.
Firsoff is an impact crater in the region called Meridiani Planum in the Oxia Palus quadrangle of Mars, located at 2.66°N latitude and 9.42°W longitude. It is 90 km in diameter. It was named after British astronomer Axel Firsoff, and the name was approved in 2010.
Crommelin is an impact crater in the Oxia Palus quadrangle of Mars, located at 5.1°N latitude and 10.2°W longitude. It is 113.9 km in diameter. It was named after British astronomer Andrew Crommelin (1865–1939), and the name was approved in 1973 by the International Astronomical Union (IAU) Working Group for Planetary System Nomenclature (WGPSN).
Equatorial layered deposits (ELD’s) have been called interior layered deposits (ILDs) in Valles Marineris. They are often found with the most abundant outcrops of hydrated sulfates on Mars, and thus are likely to preserve a record of liquid water in Martian history since hydrated sulfates are formed in the presence of water. Layering is visible on meter scale, and when the deposits are partly eroded, intricate patterns become visible. The layers in the mound in Gale Crater have been extensively studied from orbit by instruments on the Mars Reconnaissance Orbiter. The Curiosity Rover landed in the crater, and it has brought some ground truth to the observations from satellites. Many of the layers in ELD’s such as in Gale Crater are composed of fine-grained, easily erodible material as are many other layered deposits. On the basis of albedo, erosion patterns, physical characteristics, and composition, researchers have classified different groups of layers in Gale Crater that seem to be similar to layers in other (ELD’s). The groups include: a small yardang unit, a coarse yardang unit, and a terraced unit. Generally, equatorial layered deposits are found ~ ±30° of the equator. Equatorial Layered Deposits appear in various geological settings such as cratered terrains, chaotic terrains, the Valles Marineris chasmata, and large impact craters.
References
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↑ U.S. department of the Interior U.S. Geological Survey, Topographic Map of the Eastern Region of Mars M 15M 0/270 2AT, 1991
↑ Michalski; etal. (2013). "Multiple working hypotheses for the formation of compositional stratigraphy on Mars: Insights from the Mawrth Vallis region". Icarus. 226 (1): 816–840. Bibcode:2013Icar..226..816M. doi:10.1016/j.icarus.2013.05.024.
1 2 Bruckner, J., G. Dreibus, R. Rieder, and H. Wanke. 2001. Revised Data of the Mars Pathfinder Alpha Proton X-ray spectrometer: Geochemical Behavior of Major and Minor Elements. Lunar and Planetary Science XXXII
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↑ Hviid, S. et al. 1997. Magnetic Properties Experiments on the Mars Pathfinder Lander: Preliminary Results. Science:278. 1768-1770.
↑ Sanjeev Gupta, Nicholas Warner, Jung-Rack Kim, Shih-Yuan Lin, Jan Muller. 2010. Hesperian equatorial thermokarst lakes in Ares Vallis as evidence for transient warm conditions on Mars. Geology: 38. 71-74.
↑ Grotzinger, J. and R. Milliken (eds.). 2012. Sedimentary Geology of Mars. SEPM.
↑ Head, J., J. Mustard. 2006. Breccia dikes and crater-related faults in impact craters on Mars: Erosion and exposure on the floor of a crater 75 km in diameter at the dichotomy boundary, Meteorit. Planet Science: 41, 1675-1690.
↑ Mustard et al., 2007. Mineralogy of the Nili Fossae region with OMEGA/Mars Express data: 1. Ancient impact melt in the Isidis Basin and implications for the transition from the Noachian to Hesperian, J. Geophys. Res., 112.
↑ McCauley, J. F. (1973). "Mariner 9 evidence for wind erosion in the equatorial and mid-latitude regions of Mars". Journal of Geophysical Research. 78 (20): 4123–4137. Bibcode:1973JGR....78.4123M. doi:10.1029/JB078i020p04123.
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