Coprates quadrangle
Encyclopedia
The Coprates quadrangle
Quadrangle (geography)
In geology or geography, the word "quadrangle" usually refers to a United States Geological Survey 7.5-minute quadrangle map, which are usually named after a local physiographic feature. The shorthand "quad" is also used, especially with the name of the map; for example, "the Ranger Creek, Texas...

is one of a series of 30 quadrangle maps of Mars used by the United States Geological Survey
United States Geological Survey
The United States Geological Survey is a scientific agency of the United States government. The scientists of the USGS study the landscape of the United States, its natural resources, and the natural hazards that threaten it. The organization has four major science disciplines, concerning biology,...

 (USGS) Astrogeology Research Program
Astrogeology Research Program
The USGS Astrogeology Science Center has a rich history of participation in space exploration efforts and planetary mapping, starting in 1963 when the Flagstaff Science Center was established by Gene Shoemaker to provide lunar geologic mapping and assist in training astronauts destined for the...

. The Coprates quadrangle is also referred to as MC-18 (Mars Chart-18).

The Coprates quadrangle goes from 45° to 90° west longitude and 0° to 30° south latitude on Mars
Mars
Mars is the fourth planet from the Sun in the Solar System. The planet is named after the Roman god of war, Mars. It is often described as the "Red Planet", as the iron oxide prevalent on its surface gives it a reddish appearance...

.

Valles Marineris Canyon System

Valles Marineris
Valles Marineris
Valles Marineris is a system of canyons that runs along the Martian surface east of the Tharsis region...

 is an exciting place which sports the largest canyon system in the solar system; this great canyon would go almost all the way across the United States. The name for the whole system of canyons is Valles Marineris. Starting at the west with Noctis Labyrinthus
Noctis Labyrinthus
Noctis Labyrinthus, "the labyrinth of the night", is a region of Mars between the Valles Marineris and the Tharsis upland. It is located in the Phoenicis Lacus quadrangle. The region is notable for its maze-like system of deep, steep-walled valleys...

 in the Phoenicis Lacus quadrangle
Phoenicis Lacus quadrangle
The Phoenicis Lacus quadrangle is one of a series of 30 quadrangle maps of Mars used by the United States Geological Survey Astrogeology Research Program. The Phoenicis Lacus quadrangle is also referred to as MC-17 ....

, the canyon system ends in the Margaritifer Sinus quadrangle
Margaritifer Sinus quadrangle
The margaritifer Sinus quadrangle is one of a series of 30 quadrangle maps of Mars used by the United States Geological Survey Astrogeology Research Program. The Margaritifer Sinus quadrangle is also referred to as MC-19 ....

 with Capri Chasma and Eos Chasma
Eos Chasma
Eos Chasma is a chasma in the southern part of the Valles Marineris canyon system of Mars.Eos Chasma’s western floor is mainly composed of an etched massive material composed of either volcanic or eolian deposits later eroded by the Martian wind. The eastern end of the Eos chasma has a large area...

 (in the south). The word Chasma has been designated by the International Astronomical Union to refer to an elongate, steep-sided depression. Valles Marineris was discovered by and named for the Mariner 9
Mariner 9
Mariner 9 was a NASA space orbiter that helped in the exploration of Mars and was part of the Mariner program. Mariner 9 was launched toward Mars on May 30, 1971 from Cape Canaveral Air Force Station and reached the planet on November 13 of the same year, becoming the first spacecraft to orbit...

 mission. Moving east from Noctis Labyrinthus, the canyon splits into two troughs, Tithonium Chasma
Tithonium Chasma
Tithonium Chasma is a large canyon in the Coprates quadrangle of Mars at 4.6° south latitude and 84.7° west longitude. It is about 810 km long and was named after a classical albedo feature name.- Valles Marineris Canyon System :...

 and Ius Chasma
Ius Chasma
Ius Chasma is a large canyon in the Coprates quadrangle of Mars at 7° south latitude and 85.8° west longitude. It is about 938 km long and was named after a classical albedo feature name.- Valles Marineris Canyon System :...

 (in the south). In the middle of the system are the very wide valleys of Ophir Chasma
Ophir Chasma
Ophir Chasma is a canyon in the Coprates quadrangle of Mars at 4° south latitude and 72.5° west longitude. It is about 317 km long and was named after the classical albedo feature name.- Valles Marineris Canyon System :...

 (north), Candor Chasma
Candor Chasma
Candor Chasma is one of the largest canyons in the Valles Marineris canyon system on Mars. The feature is geographically divided into two halves: East and West Candor Chasmas, respectively...

, and Melas Chasma
Melas Chasma
Melas Chasma is a canyon on Mars, the widest segment of the Valles Marineris canyon system, located east of Ius Chasma at 9.8°S, 283.6°E. It cuts through layered deposits that are thought to be sediments from an old lake that resulted from runoff of the valley networks to the west. Other theories...

 (south). Going farther to the east, one comes to Coprates Chasma. At the end of Coprates Chasma, the valley gets wider to form Capri Chasma in the north and Eos Chasma
Eos Chasma
Eos Chasma is a chasma in the southern part of the Valles Marineris canyon system of Mars.Eos Chasma’s western floor is mainly composed of an etched massive material composed of either volcanic or eolian deposits later eroded by the Martian wind. The eastern end of the Eos chasma has a large area...

 in the south. The walls of the canyons often contain many layers. The floors of some of the canyons contain large deposits of layered materials. Some researchers believe that the layers were formed when water once filled the canyons. The canyons are deep as well as long. In places they are 8-10 kilometers deep. Remember the Earth's Grand Canyon
Grand Canyon
The Grand Canyon is a steep-sided canyon carved by the Colorado River in the United States in the state of Arizona. It is largely contained within the Grand Canyon National Park, the 15th national park in the United States...

 is only 1.6 kilometers deep.

In a study published in the journal Geology in August 2009, a group of scientists led by John Adams of the University of Washington in Seattle, proposed that Valles Marineris may have formed from a giant collapse when salts were heated up thereby releasing water which rushed out carrying mud through underground plumbing. One point that supports this idea is that sulfate salts have been found in the area. These salts contain water which comes off when heated. Heat may have been generated by volcanic processes. After all, a number of huge volcanoes are nearby.

Interior layered deposits and sulfate

Parts of the floor of Candor Chasma contains layered deposits that have been termed interior layered deposits (ILD's). These layers may have formed when the whole area was a giant lake.
Some places on Mars contain hydrated sulfate
Sulfate
In inorganic chemistry, a sulfate is a salt of sulfuric acid.-Chemical properties:...

 deposits. Sulfate formation involves the presence of water. The European Space Agency
European Space Agency
The European Space Agency , established in 1975, is an intergovernmental organisation dedicated to the exploration of space, currently with 18 member states...

's Mars Express
Mars Express
Mars Express is a space exploration mission being conducted by the European Space Agency . The Mars Express mission is exploring the planet Mars, and is the first planetary mission attempted by the agency. "Express" originally referred to the speed and efficiency with which the spacecraft was...

 found possible evidence of the sulfates epsomite
Epsomite
Epsomite is a hydrous magnesium sulfate mineral with formula MgSO4·7H2O or simply MgSO4. Epsomite forms as encrustations or efflorescences on limestone cavern walls and mine timbers and walls, as a volcanic fumaroles, and as rare beds in evaporate layers...

 and kieserite
Kieserite
Kieserite is a highly unstable magnesium sulfate mineral . It has a vitreous luster and it is colorless, grayish-white or yellowish. Its hardness is 3.5 and it has a monoclinic crystal system...

. Scientists want to visit these areas with robotic rovers.

Layers

Images of rocks in the canyon walls almost always show layers. Some layers appear tougher than others. In the image below of Ganges Chasma
Ganges Chasma
The Ganges Chasma is a deep canyon at the eastern end of the vast Valles Marineris system on Mars, an offshoot of Eos Chasma. It is named after the River Ganges in South Asia. It has been tentatively identified as an outflow channel....

 Layers, as seen by HiRISE
HiRISE
High Resolution Imaging Science Experiment is a camera on board the Mars Reconnaissance Orbiter. The 65 kg , $40 million instrument was built under the direction of the University of Arizona's Lunar and Planetary Laboratory by Ball Aerospace & Technologies Corp....

, one can see that the upper, light-toned deposits are eroding much faster than the lower darker layers. Some cliffs on Mars show a few darker layers standing out and often breaking into large pieces; these are thought to be hard volcanic rock instead of soft ash deposits. An example of hard layers is shown below in the picture of layers in the canyon wall in Coprates, as seen by Mars Global Surveyor
Mars Global Surveyor
The Mars Global Surveyor was a US spacecraft developed by NASA's Jet Propulsion Laboratory and launched November 1996. It began the United States's return to Mars after a 10-year absence. It completed its primary mission in January 2001 and was in its third extended mission phase when, on 2...

. Because of its closeness to the Tharsis volcanic region, the rock layers may be made of layer after layer of lava
Lava
Lava refers both to molten rock expelled by a volcano during an eruption and the resulting rock after solidification and cooling. This molten rock is formed in the interior of some planets, including Earth, and some of their satellites. When first erupted from a volcanic vent, lava is a liquid at...

 flows, probably mixed with deposits of volcanic ash that fell out of the air following big eruptions. It is likely the rock strata in the walls preserve a long geological history of Mars. Dark layers may be due to dark lava flows. The dark volcanic rock basalt
Basalt
Basalt is a common extrusive volcanic rock. It is usually grey to black and fine-grained due to rapid cooling of lava at the surface of a planet. It may be porphyritic containing larger crystals in a fine matrix, or vesicular, or frothy scoria. Unweathered basalt is black or grey...

 is common on Mars. However, light-toned deposits may have resulted from rivers, lakes, volcanic ash, or wind blown deposits of sand or dust. The Mars Rovers found light-toned rocks to contain sulfates. Probably having been formed in water, sulfate deposits are of great interest to scientists because they may contain traces of ancient life. The Mars Reconnaissance Orbiter Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) instrument found opaline silica in certain strata along and within the Valles Marineris canyon system. Because Iron sulfates were sometimes found near the opaline silica, it is thought that the two deposits were formed with an acid fluid.

Herbes Chasma and hydrated deposits

Herbes Chasma, a large enclosed valley, may have once held water. Hydrated minerals have been found there. It is thought that large-scale underground springs of groundwater at different times burst to the sufrace to form deposits called Light Toned Deposits (LTD's). Some suggest present or fossilized life forms may be found there because the deposits are relatively young.

Nirgal Vallis and sapping

Nirgal Vallis
Nirgal Vallis
Nirgal Vallis is a long river channel in the Coprates quadrangle and the Phoenicis Lacus quadrangle of Mars at 28.4° south latitude and 42° west longitude. It is 496 km long and is named after the word for "Mars" in Babylonian. The western half of Nirgal Valles is a branched system, but the...

 is one of the longest valley network on Mars. It is so large that it is found on more than one quadrangle. Scientists do not know how all the ancient river valleys were formed. There is evidence that instead of rain or snow, the water that formed the valleys originated under ground. One mechanism that has been advanced is sapping. In sapping, the ground just gives away as water comes out. Sapping is common in some desert areas in America's Southwest. Sapping forms alcoves and stubby tributaries. These features are visible in the picture below of Nigal Vallis taken with Mars Odyssey's THEMIS
Themis
Themis is an ancient Greek Titaness. She is described as "of good counsel", and is the embodiment of divine order, law, and custom. Themis means "divine law" rather than human ordinance, literally "that which is put in place", from the verb τίθημι, títhēmi, "to put"...

.

Inverted Relief

Some areas of Mars show inverted relief, where features that were once depressions, like streams, are now instead above the surface. These may have been formed when materials, like large rocks, were deposited in low-lying areas, then left behind after erosion (perhaps wind which can not move large rocks) removed much of the surface layers. Other ways of making inverted relief
Inverted Relief
Inverted relief is a landscape that is part of a planet's surface, e.g. Mars, that contains positive landforms, i.e. hills and ridges, that were once depressions in its surface...

 might be lava flowing down a stream bed or materials being cemented by minerals dissolved in water. On Earth, materials cemented by silica are highly resistant to all kinds of erosional forces. Inverted relief in the shape of streams are further evidence of water flowing on the Martian surface in past times. There are many examples of inverted channels near Juventae Chasma; some are shown in the image of Juventae Chasma below.

Vallis

Vallis (plural valles) is the Latin
Latin
Latin is an Italic language originally spoken in Latium and Ancient Rome. It, along with most European languages, is a descendant of the ancient Proto-Indo-European language. Although it is considered a dead language, a number of scholars and members of the Christian clergy speak it fluently, and...

 word for valley
Valley
In geology, a valley or dale is a depression with predominant extent in one direction. A very deep river valley may be called a canyon or gorge.The terms U-shaped and V-shaped are descriptive terms of geography to characterize the form of valleys...

. It is used in planetary geology
Planetary geology
Planetary geology, alternatively known as astrogeology or exogeology, is a planetary science discipline concerned with the geology of the celestial bodies such as the planets and their moons, asteroids, comets, and meteorites...

 for the naming of landform
Landform
A landform or physical feature in the earth sciences and geology sub-fields, comprises a geomorphological unit, and is largely defined by its surface form and location in the landscape, as part of the terrain, and as such, is typically an element of topography...

 features on other planets.

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 ideas about water on Mars; huge river valleys were found in many areas. Space craft cameras showed that floods of water broke through dams, carved deep valleys, eroded grooves into bedrock, and traveled thousands of kilometers.

See also

  • Water on Mars
    Water on Mars
    Water on Mars is a psychedelic rock and electronic music group from Quebec City, Québec, Canada. The music trio is led by Philippe Navarro, guitarist, vocalist, arranger, producer, principal lyricist, and music composer....

  • Geology of Mars
    Geology of Mars
    The geology of Mars is the scientific study of the surface, crust, and interior of the planet Mars. It emphasizes the composition, structure, history, and physical processes that shape the planet. It is fully analogous to the field of terrestrial geology. In planetary science, the term geology is...

  • Vallis
    Vallis
    Vallis is the Latin word for valley. It is used in planetary geology for the naming of landform features on other planets....

  • Chasma
    Chasma
    Chasma is a term used in astrogeology to refer to "a deep, elongated, steep-sided depression". The plural is chasmata. An example is Eos Chasma on Mars. Below are images of some of the major chasmata of Mars...

  • Inverted Relief
    Inverted Relief
    Inverted relief is a landscape that is part of a planet's surface, e.g. Mars, that contains positive landforms, i.e. hills and ridges, that were once depressions in its surface...


External links

The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
x
OK