{{Short description|Martian geographical feature}} {{Infobox feature on celestial object |name = Elysium Fossae |image = [[Image:Elysium map.JPG|200px]] |caption = Map of [[Elysium quadrangle]]. [[Elysium Mons]] and [[Albor Tholus]] are large volcanoes. The Elysium Fossae are in the upper left (northwest). |coordinates = {{coord|24.8|N|213.7|W|globe:mars_type:landmark|display=inline,title}} }} The '''Elysium Fossae''' are a group of large troughs in the [[Elysium quadrangle]] of Mars at 24.8° north latitude and 213.7° west longitude. They are about 1,175&nbsp;km long and are named after a classical albedo feature name.<ref>{{cite web|url=https://planetarynames.wr.usgs.gov/Feature/1782|title=Planetary Names: Elysium Fossae|website=planetarynames.wr.usgs.gov|access-date=17 December 2018}}</ref>

==Troughs== Large troughs (long narrow depressions) are called fossae in the geographical language used for Mars. Troughs are created when the crust is stretched until it breaks. The stretching can be due to the large weight of a nearby volcano. Fossae/pit craters are common near volcanoes in the Tharsis and Elysium system of volcanoes.<ref>Skinner, J., L. Skinner, and J. Kargel. 2007. Re-assessment of Hydrovolcanism-based Resurfacing within the Galaxias Fossae Region of Mars. Lunar and Planetary Science XXXVIII (2007)</ref> A trough often has two breaks with a middle section moving down, leaving steep cliffs along the sides; such a trough is called a graben.<ref>{{cite web|url=http://hirise.lpl.arizona.edu/PSP_008641_2105|title=Craters and Pit Crater Chains in Chryse Planitia (PSP_008641_2105)|website=HiRISE|access-date=30 September 2018}}</ref> [[Lake George (lake), New York|Lake George]], in northern [[New York State]], is a lake that sits in a graben. <gallery class="center" widths="190px" heights="180px" > ESP 045741 2080troughs.jpg|Troughs showing layers and dark slope streaks, as seen by HiRISE under HiWish program

</gallery>

== Layers == The Elysium Fossae contain layers, also called strata. Many places on Mars show rocks arranged in layers. Sometimes the layers are of different colors. Light-toned rocks on Mars have been associated with hydrated minerals like sulfates. The [[Mars rover]] ''[[Opportunity (rover)|Opportunity]]'' examined such layers close-up with several instruments. Some layers are probably made up of fine particles because they seem to break up into find dust. Other layers break up into large boulders so they are probably much harder. Basalt, a volcanic rock, is thought to in the layers that form boulders. Basalt has been identified on Mars in many places. Instruments on orbiting spacecraft have detected clay (also called phyllosilicates) in some layers. Scientists are excited about finding hydrated minerals such as sulfates and clays on Mars because they are usually formed in the presence of water.<ref>{{cite web|url=http://themis.asu.edu/features/nilosyrtis|title=Target Zone: Nilosyrtis? - Mars Odyssey Mission THEMIS|website=themis.asu.edu|access-date=30 September 2018}}</ref> Places that contain clays and/or other hydrated minerals would be good places to look for evidence of life.<ref>{{cite web|url=http://hirise.lpl.arizona.edu/PSP_004046_2080|title=Craters and Valleys in the Elysium Fossae (PSP_004046_2080)|website=HiRISE|access-date=30 September 2018}}</ref>

Rock can form layers in a variety of ways. Volcanoes, wind, or water can produce layers.<ref>{{cite web|url=http://hirise.lpl.arizona.edu?PSP_008437_1750|title=HiRISE - High Resolution Imaging Science Experiment|website=HiRISE|access-date=30 September 2018}}</ref>

<gallery class="center" widths="190px" heights="180px" > Image:Elysium Fossae.JPG|Elysium Fossae, as seen by [[HiRISE]]. Click on image to see layers. </gallery> {{commonscat|Elysium Fossae}}

==References== {{reflist}}

==See also==

* [[Fossa (geology)]] * [[Geology of Mars]] * [[HiRISE]] * [[HiWish program]]

{{Geography of Mars}} {{Portal bar|Solar System}}

[[Category:Elysium quadrangle]] [[Category:Valleys and canyons on Mars]]