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32-651: The Louros Valles are a system of valleys on the planet Mars in the Coprates quadrangle . They sit on the southern edge of Ius Chasma . They are east of Noctis Labyrinthus . They display many layers in their sidewalls. Many other places on Mars also show rocks arranged in layers. Rock layers can be formed by volcanoes, wind, or water. A detailed discussion of layering with many Martian examples can be found in Sedimentary Geology of Mars. The Louros Valles are centered at 8.41 S and 278.23 E, and were named after

64-583: 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,

96-878: A modern river in Greece. The name was approved in 1982. The following set of images start with wide views of the whole planet that are centered near the Louros Valles. They transition to close views with enlarged HiRISE images. Coprates quadrangle 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 . The Coprates quadrangle goes from 45° to 90° west longitude and 0° to 30° south latitude on Mars . Coprates quadrangle

128-595: A number of huge volcanoes are nearby. Other ideas have been advanced by others to explain the origin of the system. 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. High-resolution structural and geologic mapping in west Candor Chasma, presented in March 2015, showed that

160-643: 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 ( Arabia Terra , Meridiani Planum ), chaotic terrains ( Aram Chaos , Aureum Chaos ), the Valles Marineris chasmata (and surrounding plateaus), and large impact craters ( Gale, Becquerel, Crommelin). Some ELD’s have been closely studied in Firsoff Crater . Changes in

192-511: 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

224-567: Is estimated that Nirgal Vallis had a discharge of 4800 cubic meters/second. 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. Water with a depth of at least 50 m entered Holden at a rate that 5–10 times the discharge of the Mississippi River. Terraces and

256-569: 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. 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

288-599: 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. Dark layers may be due to dark lava flows. The dark volcanic rock basalt

320-551: Is the Great Artesian Basin of Australia . On Earth the hardness of many sedimentary rocks , like sandstone , is largely due to the cement that was put in place as water passed through. Much strong evidence for groundwater cementing materials comes from the results of the Opportunity Rover . Some places, examined by Opportunity such as Endurance, Eagle, and Erebus craters have been found to be where

352-721: 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. 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

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384-712: 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:

416-516: 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. 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

448-431: The area around the crater. So, the model predicts that layers may also have formed in intercrater regions, and layers in these regions have been observed. Layers can be hardened by the action of groundwater. Martian ground water probably moved hundreds of kilometers, and in the process it dissolved many minerals from the rock it passed through. When ground water surfaces in low areas containing sediments, water evaporates in

480-414: The atmosphere of Mars will be much thicker and contain more moisture. The amount of atmospheric dust also has increased and decreased. It is believed that these frequent changes helped to deposit material in craters and other low places. The rising of mineral-rich ground water cemented these materials. The model also predicts that after a crater is full of layered rocks; additional layers will be laid down in

512-407: 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

544-539: 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, much deeper than the Earth's Grand Canyon , which is only 1.6 kilometers deep. In a study published in the journal Geology in August 2009,

576-406: The deposits are relatively young. 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 . In sapping,

608-583: 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. 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. These deposits have been found to contain ferric oxides in

640-515: The form of crystalline grey hematite. Images of rocks in the canyon walls almost always show layers. 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

672-458: 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

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704-890: The image of Juventae Chasma below. 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. Recurrent slope lineae (RSL) are small dark streaks on slopes that elongate in warm seasons. They may be evidence of liquid water. Deposits of water ice have been found in Candor Chaos in

736-619: The layering in Firsoff Crater, which is a candidate for a rover landing in 2020. Many depositional processes have been proposed to explain Equatorial Layered Deposits (ELDs) formation, such as volcanoes under ice, dust from the air, lake deposits, and mineral deposits from springs. Groundwater may have played an important part in forming layers in many locations. Calculations and simulations show that groundwater carrying dissolved minerals would surface in

768-462: The level of groundwater seem to be the major factor controlling ELD deposition in and around Firsoff Crater. The layers inside Firsoff and other nearby craters would likely have started with fluid upwelling through fissures and mounds, which later lead to evaporite precipitation. Spring and playa deposits suggest the presence of a hydrological cycle, driving groundwater upwelling on Mars at surface temperatures above freezing. Pictures below show some of

800-580: 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. The instrument involved is called the Fine-Resolution Epithermal Neutron Detector (FREND). Candor Chaos is about the size of the a Netherlands. Equatorial layered deposits Equatorial layered deposits (ELD’s) have been called interior layered deposits (ILDs) in Valles Marineris . They are often found with

832-522: 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

864-419: The presence of large rocks (tens of meters across) support these high discharge rates. 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

896-490: The same locations that have abundant rock layers. According to these ideas, deep canyons and large craters would receive water coming from the ground. Many craters in the Arabia area of Mars contain groups of layers. Some of these layers may have resulted from climate changes. The tilt of the rotational axis of Mars has repeatedly changed in the past. Some changes are large. Because of these variations of climate, at times

928-455: 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

960-452: The thin atmosphere and leaves behind minerals as deposits and/or cementing agents. Consequently, layers of dust could not later easily erode away since they were cemented together. On Earth, mineral-rich waters often evaporate forming large deposits of various types of salts and other minerals . Sometimes water flows through Earth's aquifers, and then evaporates at the surface just as is hypothesized for Mars. One location this occurs on Earth

992-488: The water table breached the surface., Also, it was discovered that wind-driven currents of water transported sediment at these locations. Small surface cracks are thought to have formed during multiple wetting and drying events, so they are evidence that the groundwater rose and fell. Ferric sulfates (such as jarosite ) in the rocks of Meridiani Planum indicates that acidic fluids were present. These acidic liquids could have been produced when water with dissolved Fe(II)

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1024-697: 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,

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