{{Short description|Canyon on Mars}} {{Infobox feature on celestial object |name = Ophir Chasma |image = Ophir_Chasma_based_on_day_THEMIS.png |caption = Ophir Chasma based on [[Thermal Emission Imaging System|THEMIS]] mosaic |coordinates = {{coord|4|S|72.5|W|globe:mars_type:landmark|display=inline,title}} }} [[Image:Ophir Chasma THEMIS mosaic.jpg|250px|thumb|Ophir Chasma in mosaic of [[Thermal Emission Imaging System|THEMIS]] infrared images, with part of [[Candor Chasma]] at bottom]]
'''Ophir Chasma''' {{IPAc-en|'|oʊ|f|ər|_|'|k|æ|z|m|ə}} 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.<ref name=gpn>{{gpn|4476|Ophir Chasma}}</ref><ref>{{gpn|4473|Ophir}}</ref> In the Bible it was the land which King Solomon sent an expedition that returned with gold.<ref>Blunck, J. 1982. Mars and its Satellites. Exposition Press. Smithtown, N.Y.</ref> It is a [[Classical albedo features on Mars|classical albedo feature]] name.<ref name=gpn/>
== Valles Marineris canyon system == [[Image:Coprates map.JPG|thumb|left|Map of [[Coprates quadrangle]] showing details of [[Valles Marineris]], the largest canyon system in the [[Solar System]]. Some of the canyons may have once been filled with water.]]
Ophir Chasma is part of 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 parallel troughs, [[Tithonium Chasma]] to the North and [[Ius Chasma]] to the south. In the middle of the system are 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. The canyons are deep as well as long. In places they are 8-10 kilometers deep. In comparison, Earth's [[Grand Canyon]] is 1.6 kilometers deep.<ref>{{cite book | isbn=0-8165-1257-4 | title=Mars: Maps | last1=Kieffer | first1=Hugh H. | date=October 1992 | publisher=University of Arizona Press }}</ref>
== Layers == [[Image:Ophir Chasma Wall.JPG|thumb|Ophir Chasma wall, as seen by [[HiRISE]].]]
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. 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.<ref>{{Cite web|url=http://themis.asu.edu/features/coprateschasma|title=Landslides and Debris in Coprates Chasma | Mars Odyssey Mission THEMIS}}</ref> 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.<ref>{{Cite web|url=http://hirise.lpl.arizona.edu/PSP_005385_1640|title=HiRISE | Light-toned Layers in Eos Chaos (PSP_005385_1640)}}</ref> 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.<ref>http://hirise,lpl.arizona.edu/PSP_007430_1725{{dead link|date=January 2018 |bot=InternetArchiveBot |fix-attempted=yes }}</ref>
== Gallery == {| |- |[[File:Ophir Chasma.jpg|thumb|{{center|Synthetic oblique view of Ophir Chasma from [[Viking program|Viking orbiter]] images.}}]] |} On August 19, 2015, ISRO released the [http://www.isro.gov.in/pslv-c25-mars-orbiter-mission/3d-portrayals-of-ophir-chasma-terrain 3D portrayals] {{Webarchive|url=https://web.archive.org/web/20150818090527/http://www.isro.gov.in/pslv-c25-mars-orbiter-mission/3d-portrayals-of-ophir-chasma-terrain |date=2015-08-18 }} of Ophir Chasma taken by Mars Orbiter Mission.
==See also== * [[Chasma]] * [[Climate on Mars]] * [[Geology of Mars]] * [[HiRISE]] * [[Tectonics of Mars]]
== References == {{commons category|Ophir Chasma}} {{reflist}}
==External links== *{{APOD |date=13 February 2003|title=Candor and Ophir Chasmatai}} *{{APOD |date=17 February 2005|title=Melas, Candor and Ophir: Valleys of Mariner}}
{{Geography of Mars}} {{Portal bar|Solar System}}
[[Category:Coprates quadrangle]] [[Category:Valleys and canyons on Mars]]