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Coordinates | 15°00′S67°30′W / 15°S 67.5°W |
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The Coprates quadrangle is one of a series of 30 quadrangle maps of Mars used by the United States Geological Survey (USGS) Astrogeology Research Program. The Coprates quadrangle is also referred to as MC-18 (Mars Chart-18). [1] The Coprates quadrangle contains parts of many of the old classical regions of Mars: Sinai Planum, Solis Planum, Thaumasia Planum, Lunae Planum, Noachis Terra, and Xanthe Terra.
The name Coprates refers to Coprates Chasma, a central trough of the Valles Marineris, named after the Greek name of the Dez River in Persia. [2]
The Coprates quadrangle goes from 45° to 90° west longitude and 0° to 30° south latitude on Mars. Coprates quadrangle is famous for depicting the "Grand Canyon of Mars", the Valles Marineris Canyon System. Signs of water exist in this quadrangle, with ancient river valleys and networks of stream channels showing up as inverted terrain and lakes inside of Valles Marineris. [3]
Coprates is the name of a telescopic albedo feature located at 15° S and 60° W on Mars. It is named after the Coprates River, an ancient name for the Dez, a tributary of the Karun in modern Iran which empties into the Shatt al-Arab near its Persian Gulf estuary. The name was approved by the International Astronomical Union (IAU) in 1958. [4] [5]
Valles Marineris is 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 in the Phoenicis Lacus quadrangle, the canyon system ends in the Margaritifer Sinus quadrangle with Capri Chasma and Eos Chasma (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 mission. Moving east from Noctis Labyrinthus, the canyon splits into two troughs, Tithonium Chasma and Ius Chasma (in the south). In the middle of the system are the very wide valleys of Ophir Chasma (north), Candor Chasma, and Melas Chasma (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 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. [3] [6] [7] [8] The canyons are deep as well as long; in places they are 8–10 kilometers deep, much deeper than the Earth's Grand Canyon, which is only 1.6 kilometers deep. [9]
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. [10] Other ideas have been advanced by others to explain the origin of the system. [3]
Parts of the floors of Candor Chasma and Juventae Chasma contain layered deposits that have been termed interior layered deposits (ILD's) and equatorial layered deposits (ELDs). These layers may have formed when the whole area was a giant lake. However, many other ideas have been advanced to explain them. [3] High-resolution structural and geologic mapping in west Candor Chasma, presented in March 2015, showed that the deposits on the floor of the Candor chasma are basin filling sediments that were deposited in a wet playa like setting; hence water was involved in their formation. [11]
Some places on Mars contain hydrated sulfate deposits, including ILD's. Sulfate formation involves the presence of water. The European Space Agency's Mars Express found possible evidence of the sulfates epsomite and kieserite. Scientists want to visit these areas with robotic rovers. [12]
These deposits have been found to contain ferric oxides in the form of crystalline grey hematite. [3] [13] [14]
Images of rocks in the canyon walls almost always show layers. [15] Some layers appear tougher than others. In the image below of Ganges Chasma Layers, as seen by HiRISE, 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. Because of its closeness to the Tharsis volcanic region, the rock layers may be made of layer after layer of lava 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. [16] Dark layers may be due to dark lava flows. The dark volcanic rock basalt is common on Mars. However, light-toned deposits may have resulted from rivers, lakes, volcanic ash, or wind blown deposits of sand or dust. [17] 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. [18] 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. [19] Because Iron sulfates were sometimes found near the opaline silica, it is thought that the two deposits were formed with an acid fluid. [20]
Hebes 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 surface to form deposits called Light Toned Deposits (LTDs). Some suggest present or fossilized life forms may be found there because the deposits are relatively young. [21]
Nirgal Vallis is one of the longest valley networks 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 underground. One mechanism that has been advanced is sapping. [22] 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.
Water from Nirgal Vallis contributed to a great flood that went through the rim of Holden Crater and helped form a lake in the crater. It is estimated that Nirgal Vallis had a discharge of 4800 cubic meters/second. [23] Water from Nirgal Vallis was inbounded in Uzboi Vallis because the rim of Holden Crater blocked the flow. At a certain point the stored water broke through the rim of Holden and created a lake 200–250 m deep. [24] Water with a depth of at least 50 m entered Holden at a rate that 5–10 times the discharge of the Mississippi River. [25] [26] [27] [28] Terraces and the presence of large rocks (tens of meters across) support these high discharge rates. [24] [25] [29] [30] [31]
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 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. [32] [33] [34]
Vallis (plural valles) is the Latin word for valley . It is used in planetary geology for the naming of landform 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. [9] [35] [36]
Recurrent slope lineae (RSL) are small dark streaks on slopes that elongate in warm seasons. They may be evidence of liquid water. [37] [38] [39]
Deposits of water ice have been found in Candor Chaos in the middle area of Valles Marineris. The neutron telescope on EXoMars found that up to 40.3 wt% of the top meter of soil is probably water ice. [40] [41] The instrument involved is called the Fine-Resolution Epithermal Neutron Detector (FREND). Candor Chaos is about the size of the a Netherlands. [42]
Valles Marineris is a system of canyons that runs along the Martian surface east of the Tharsis region. At more than 4,000 km (2,500 mi) long, 200 km (120 mi) wide and up to 7 km (23,000 ft) deep, Valles Marineris is the largest canyon in the Solar System.
Vallis or valles is the Latin word for valley. It is used in planetary geology to name landform features on other planets.
The Thermal Emission Imaging System (THEMIS) is a camera on board the 2001 Mars Odyssey orbiter. It images Mars in the visible and infrared parts of the electromagnetic spectrum in order to determine the thermal properties of the surface and to refine the distribution of minerals on the surface of Mars as determined by the Thermal Emission Spectrometer (TES). Additionally, it helps scientists to understand how the mineralogy of Mars relates to its landforms, and it can be used to search for thermal hotspots in the Martian subsurface.
Eos Chasma is a chasma in the southern part of the Valles Marineris canyon system of the Coprates quadrangle and the Margaritifer Sinus quadrangles of the planet Mars.
In planetary nomenclature, a chasma is a deep, elongated, steep-sided depression. As of 2020, the IAU has named 122 such features in the Solar System, on Venus (63), Mars (25), Saturn's satellites Mimas (6), Tethys (2), Dione (8) and Rhea (5), Uranus's satellites Ariel (7), Titania (2) and Oberon (1) and Pluto's satellite Charon (3). An example is Eos Chasma on Mars.
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. It is unclear how the canyon originally formed; one theory is that it was expanded and deepened by tectonic processes similar to a graben, while another suggests that it was formed by subsurface water erosion similar to a karst. MRO discovered sulfates, hydrated sulfates, and iron oxides in Candor Chasma.
Juventae Chasma is an enormous box canyon on Mars which opens to the north and forms the outflow channel Maja Valles. Juventae Chasma is located north of Valles Marineris in the Coprates quadrangle and cuts more than 5 km into the plains of Lunae Planum.
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 in Coprates quadrangle. 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 include windblown sediment deposits and volcanic ash. Support for abundant, past water in Melas Chasma is the discovery by MRO of hydrated sulfates. In addition, sulfate and iron oxides were found by the same satellite. Although not chosen as one of the finalists, it was one of eight potential landing sites for the Mars 2020 rover, a mission with a focus on astrobiology.
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 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.
Eos Chaos is a rough, collapsed area in the Coprates quadrangle on Mars at 16.8° south latitude and 46.9° west longitude. It is about 490 km long and was named after the Greek name of Aurora, an albedo feature.
Capri Mensa is a mesa in the Coprates quadrangle of Mars at 14° south latitude and 47.4° west longitude. It is about 275 km long and was named after a classical albedo feature name.
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 Ophir, a land mentioned in the Bible. In the Bible it was the land which King Solomon sent an expedition that returned with gold. It is a classical albedo feature name.
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.
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.
Coprates Chasma is a huge canyon in the Coprates quadrangle of Mars, located at 13.4° south latitude and 61.4° west longitude, part of the Valles Marineris canyon system. It is 966 km (600 mi) long and was named after a classical albedo feature name. It was named from the classical Greek name for the Dez River in Persia.
To date, interplanetary spacecraft have provided abundant evidence of water on Mars, dating back to the Mariner 9 mission, which arrived at Mars in 1971. This article provides a mission by mission breakdown of the discoveries they have made. For a more comprehensive description of evidence for water on Mars today, and the history of water on that planet, see Water on Mars.
The Mars Reconnaissance Orbiter's HiRISE instrument has taken many images that strongly suggest that Mars has had a rich history of water-related processes. Many features of Mars appear to be created by large amounts of water. That Mars once possessed large amounts of water was confirmed by isotope studies in a study published in March 2015, by a team of scientists showing that the ice caps were highly enriched with deuterium, heavy hydrogen, by seven times as much as the Earth. This means that Mars has lost a volume of water 6.5 times what is stored in today's polar caps. The water for a time would have formed an ocean in the low-lying Mare Boreum. The amount of water could have covered the planet about 140 meters, but was probably in an ocean that in places would be almost 1 mile deep.
The Mars orbiter 2001 Mars Odyssey found much evidence for water on Mars in the form of pictures, and with a spectrometer it proved that much of the ground is loaded with ice.
In summer 1965, the first close-up images from Mars showed a cratered desert with no signs of water. However, over the decades, as more parts of the planet were imaged with better cameras on more sophisticated satellites, Mars showed evidence of past river valleys, lakes and present ice in glaciers and in the ground. It was discovered that the climate of Mars displays huge changes over geologic time because its axis is not stabilized by a large moon, as Earth's is. Also, some researchers maintain that surface liquid water could have existed for periods of time due to geothermal effects, chemical composition, or asteroid impacts. This article describes some of the places that could have held large lakes.
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