Editing Valles Marineris (section)

=== Coprates Chasma ===
[[Image:PIA19805-SeasonalFlows-CopratesChasma-VallesMarineris-20150721.jpg|thumb|left|250px|[[Seasonal flows on warm Martian slopes|Seasonal flows]] on [[Coprates Chasma]] in Valles Marineris.]]
[[Image:Coprates Chasma landslides.jpg|right|thumb|260px|Deposits from landslides moving in opposite directions meet on the canyon floor near the junction of Melas and Coprates chasmata.]]
Further to the east, the canyon system runs into [[Coprates Chasma]], which is very similar to Ius and Tithonium chasmata. Coprates differs from Ius in the eastern end which contains alluvial deposits and [[Aeolian processes|eolian]] material<ref name="USGS I-2010"/> and like Ius, has layered deposits, although the deposits in the Coprates Chasma are much more well defined. These deposits pre-date the Valles Marineris system, suggesting erosion and sedimentary processes later cut by the Valles Marineris system. Newer data from [[Mars Global Surveyor]] suggest that the origin of this layering is either just a succession of [[landslide]]s, one over another, volcanic in origin, or it may be the bottom of a basin of either liquid or solid water ice suggesting that the peripheral canyons of the Valles Marineris system could have been at one time isolated lakes formed from erosional collapse. Another possible source of the layered deposits could be wind-blown, but the diversity of the layers suggests that this material is not dominant. Note that only the upper layers are thin, while the bottom layers are very big, suggesting that the lower layers were composed of mass wasted rock and the upper layers come from another source.<ref>{{Cite book |last=Cattermole |first=Peter John |url=https://archive.org/details/marsmysteryunfol00catt |title=Mars : the mystery unfolds |date=2001 |publisher=Oxford ; New York : Oxford University Press |others=Internet Archive |isbn=978-0-19-521726-1 |pages=113-114}}</ref> Some of this layering may have been transferred to the floor by landslides in which the layers are kept semi-intact, yet the layered section looks highly deformed with thickening and thinning beds that have multitudes of folds in them as seen in MOC image #8405. This complex terrain could also be just eroded sediment from an ancient Martian lake-bed and appear complex because all that we have is an aerial view like a geologic map and not enough elevation data to see if the beds are horizontal.

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 slope upward before reaching the outflow channels, which means that if you poured fluid into this part of the canyon, it would form a lake with a depth of {{convert|1|km|ft|abbr=on}} before spilling over towards the northern plains.<ref>[https://archive.org/details/marsmysteryunfol00catt/page/105 Cattermole, 105]</ref>

A field of more than 100 pitted cones on the floor of Coprates Chasma has been interpreted as a set of small igneous [[cinder cone|cinder]] or [[tuff cone|tuff]] cones, with associated lava flows. Crater dating indicates they are of Middle to Late [[Amazonian (Mars)|Amazonian]] age, about 200 to 400 million years old.<ref name = "CzechAcad2017">{{cite web | url = http://www.avcr.cz/en/media/news-archive/Recent-volcanic-activity-and-hydrothermal-minerals-on-Mars/ | title = Recent volcanic activity and hydrothermal minerals on Mars | date =  2017-07-19 | publisher = [[Czech Academy of Sciences]] | access-date = 2017-07-27}}</ref><ref name="Brož2017">{{cite journal|last1= Brož|first1= P.|last2= Hauber|first2= E.|last3= Wray|first3=J. J.|last4= Michael|first4= G.|title= Amazonian volcanism inside Valles Marineris on Mars|journal= Earth and Planetary Science Letters|volume= 473|year= 2017|pages= 122–130|doi= 10.1016/j.epsl.2017.06.003|url=https://zenodo.org/record/889306|bibcode= 2017E&PSL.473..122B}}</ref>