{{Short description|Chasma on Mars}} {{Infobox feature on celestial object |name = Coprates Chasma |image = [[Image:Coprates Chasma THEMIS mosaic 0.5.jpg|300px]] |caption = Coprates Chasma in mosaic of [[Thermal Emission Imaging System|THEMIS]] infrared images, with parts of [[Melas Chasma|Melas]] and [[Capri Chasma|Capri]] chasmata visible at upper left and lower right, respectively. Landslide deposits of enormous size are visible at left, near the junction with Melas Chasma, and at various locations from center to right. Several smaller [[chasma]]ta and [[Crater chain|catenae]] parallel Coprates Chasma to its south. |coordinates = {{coord|13.4|S|61.4|W|globe:mars_type:landmark|display=inline,title}} }} [[File:Coprates Chasma based on THEMIS Day IR.png|thumb|Coprates Chasma based on THEMIS data]] '''Coprates Chasma''' ({{IPAc-en|'|k|ɒ|p|r|ə|t|i:|z|_|'|k|æ|z|m|ə}}) 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 {{convert|966|km|abbr=on}} long and was named after a classical albedo feature name.<ref>{{Cite web|url=https://planetarynames.wr.usgs.gov/Feature/1302;jsessionid=DF387ED174AF21E6F11F99C4D4044B62|title=Planetary Names: Chasma, chasmata: Coprates Chasma on Mars|website=planetarynames.wr.usgs.gov|language=en|access-date=2018-03-20}}</ref> It was named from the classical Greek name for the [[Dez River]] in Persia.
Near 60° W is the deepest point of the Valles Marineris system (as well as its lowest point by elevation) at {{convert|11|km|ft|abbr=on}} below the surrounding plateau. Eastward from here there is about a 0.03 degree upward slope before reaching the outflow channels, which means that if you filled the canyon with fluid, it would create a lake with a depth of {{convert|1|km|ft|abbr=on}} before the fluid would overflow out onto the northern plains.<ref name=Cattermole>{{cite book |author=Cattermole, Peter John |title=Mars: the mystery unfolds |publisher=[[Oxford University Press]] |date=2001 |page=[https://archive.org/details/marsmysteryunfol00catt/page/105 105] |isbn=0-19-521726-8 |url-access=registration |url= https://archive.org/details/marsmysteryunfol00catt }}</ref>
Keith Harrison and Mary Chapman described strong evidence for a former lake in the eastern part of Valles Marineris, especially in Coprates Chasma. It would have had an average depth of only 842 m—much smaller than the 5–10 km depth of parts of Valles Marineris. Still, its volume of 110,000 cubic miles would be comparable to Earth’s [[Caspian Sea|Caspian]] and [[Black Sea]]s. The main evidence for such a lake is the presence of benches at the level that models show is where the lake level should be. Also, the low point in Eos Chasma where water would be expected to overflow is marked by fluvial features. The features look like the flow came together at a small point and carried out significant erosion.<ref>{{Cite book |last=Harrison |first=Keith P. |title=Lakes on Mars |last2=Chapman |first2=Mary G. |date=2010 |publisher=Elsevier |isbn=978-0444528544 |editor-last=Cabrol |editor-first=N. A. |location=NY |chapter=Episodic ponding and outburst flooding associated with chaotic terrains in Valles Marineris |bibcode=2010lama.book..163H |doi=10.1016/B978-0-444-52854-4.00006-4 |editor-last2=Grin |editor-first2=E. A.}}</ref><ref>{{Cite journal |last=Harrison |first=Keith P. |last2=Chapman |first2=Mary G. |date=2008 |title=Evidence for ponding and catastrophic floods in central Valles Marineris, Mars |journal=Icarus |volume=198 |issue=2 |pages=351–364 |doi=10.1016/j.icarus.2008.08.003 |issn=0019-1035}}</ref>
The bottom of the Coprates Chasma contain a large field of small pitted cones which have been interpreted as Martian equivalents of terrestrial igneous<ref>{{cite journal|last1=Brož|first1=Petr|last2=Hauber|first2=Ernst|last3=Wray|first3=James J.|last4=Michael|first4=Gregory|title=Amazonian volcanism inside Valles Marineris on Mars|journal=Earth and Planetary Science Letters|date=September 2017|volume=473|pages=122–130|doi=10.1016/j.epsl.2017.06.003|url=https://zenodo.org/record/889306|bibcode=2017E&PSL.473..122B}}</ref> or mud volcanoes.<ref>{{cite journal|last1=Okubo|first1=Chris H.|title=Morphologic evidence of subsurface sediment mobilization and mud volcanism in Candor and Coprates Chasmata, Valles Marineris, Mars|journal=Icarus|date=May 2016|volume=269|pages=23–37|doi=10.1016/j.icarus.2015.12.051|bibcode=2016Icar..269...23O|url=https://zenodo.org/record/1259053}}</ref>
==Recurrent slope lineae==
Recurrent slope lineae are small dark streaks on slopes that elongate in warm seasons. They may be evidence of liquid water.<ref>{{Cite journal |last=McEwen |first=Alfred S. |last2=Dundas |first2=Colin M. |last3=Mattson |first3=Sarah S. |last4=Toigo |first4=Anthony D. |last5=Ojha |first5=Lujendra |last6=Wray |first6=James J. |last7=Chojnacki |first7=Matthew |last8=Byrne |first8=Shane |last9=Murchie |first9=Scott L. |last10=Thomas |first10=Nicolas |display-authors=3 |date=2014 |title=Recurring slope lineae in equatorial regions of Mars |journal=Nature Geoscience |volume=7 |issue=1 |pages=53–58 |doi=10.1038/ngeo2014 |issn=1752-0894}}</ref><ref>{{Cite journal |last=McEwen |first=Alfred S. |last2=Ojha |first2=Lujendra |last3=Dundas |first3=Colin M. |last4=Mattson |first4=Sarah S. |last5=Byrne |first5=Shane |last6=Wray |first6=James J. |last7=Cull |first7=Selby C. |last8=Murchie |first8=Scott L. |last9=Thomas |first9=Nicolas |last10=Gulick |first10=Virginia C. |display-authors=3 |date=2011 |title=Seasonal Flows on Warm Martian Slopes |journal=Science |volume=333 |issue=6043 |pages=740–743 |doi=10.1126/science.1204816 |issn=0036-8075}}</ref><ref>{{Cite web|url=http://redplanet.asu.edu/?tag=recurring-slope-lineae|title=recurring slope lineae {{!}} Red Planet Report|website=redplanet.asu.edu|language=en-US|access-date=2018-03-20}}</ref>
<gallery class="center" widths="190px" heights="180px" > ESP 049955 1665rslbox.jpg|Wide view of part of Valles Marineris, as seen by HiRISE under HiWish program Box shows location of recurrent slope lineae that are enlarged in next image. 49955 1665rslcolorarrows.jpg|Close, color view of recurrent slope lineae, as seen by HiRISE under HiWish program Arrows point to some of the recurrent slope lineae. 49955 1665rsldrawing6.jpg|Recurrent slope lineae elongate when the slopes are at their warmest. Near the equator, RSL elongate on northern slopes in the northern summer and on the southern slopes in the southern summer. </gallery>
==Gallery==
<gallery widths="260px" heights="300px"> File:Top of Coprates Chasma.jpg|South rim of Coprates Chasma, image is about a kilometer wide. With enhanced IR colors, we see a portion of the very top of the south wall of the canyon, looking down onto the steep upper slopes of the canyon. Image:Corprates Chasma Fault.JPG|[[Fault (geology)|Fault]]s, as seen by [[HiRISE]]. Layers in the rock face may be from [[volcanic]], [[Lake|lacustrine]], and/or [[Aeolian processes|aeolian]] sediments deposited in [[Valles Marineris]]. Image:PIA19805-SeasonalFlows-CopratesChasma-VallesMarineris-20150721.jpg|[[Seasonal flows on warm Martian slopes|Seasonal flows]] on Coprates Chasma in [[Valles Marineris]]. </gallery> {{commons category|Coprates Chasma}}
==See also== * [[Lakes on Mars]]
==References== {{Reflist}}
{{Geography of Mars}} {{Portal bar|Solar System}}
[[Category:Coprates quadrangle]] [[Category:Valleys and canyons on Mars]]