{{Short description|Map of Mars}} {{Infobox feature on celestial object |name = Eridania quadrangle |image = [[File:USGS-Mars-MC-29-EridaniaRegion-mola.png|300px]] |caption = Map of Eridania quadrangle from [[Mars Orbiter Laser Altimeter]] (MOLA) data. The highest elevations are red and the lowest are blue. |coordinates = {{coord|47.5|S|210|W|globe:mars_type:landmark|display=inline,title}} }} [[File:PIA00189-MC-29-EridaniaRegion-19980605.jpg|thumb|300px|Image of the Eridania Quadrangle (MC-29). The region mainly includes heavily cratered highlands. The west-central part includes [[Kepler (Martian crater)|Kepler Crater]].]] The '''Eridania quadrangle''' is one of a series of [[list of quadrangles on Mars|30 quadrangle maps of Mars]] used by the [[United States Geological Survey]] (USGS) [[Astrogeology Research Program]]. The Eridania [[quadrangle (geography)|quadrangle]] is also referred to as MC-29 (Mars Chart-29).<ref>Davies, M.E.; Batson, R.M.; Wu, S.S.C. “Geodesy and Cartography” in Kieffer, H.H.; Jakosky, B.M.; Snyder, C.W.; Matthews, M.S., Eds. ''Mars.'' University of Arizona Press: Tucson, 1992.</ref>

The Eridania quadrangle lies between 30° and 65° south latitude and 180° and 240° west longitude on the planet [[Mars]]. Most of the classic region named [[Terra Cimmeria]] is found within this quadrangle. It is named after a region on the Po River, Italy. The name was approved by the IAUP in 1958.<ref>{{Cite web |title=Planetary Names |url=https://planetarynames.wr.usgs.gov/Feature/1826 |access-date=2024-07-27 |website=planetarynames.wr.usgs.gov}}</ref><ref> Proceedings of the General Assembly in Transactions of the International Astronomical Union, vol. XB, 1958, through XXVB, 2003.</ref>

Part of the [[Electris deposits]], a 100–200 meters thick, light-toned deposit covers the Eridania quadrangle.<ref>Grant, J. and P. Schultz. 1990. Gradational epochs on Mars: Evidence from west-northwest of Isidis Basin and Electric. Icarus: 84. 166-195.</ref> Many slopes in Eridania contain gullies, which are believed to be caused by flowing water.

==Martian gullies== [[File:ESP 082970 1465gullieswide 01.jpg|thumb|upright=1.2|Wide view of gullies in a crater, as seen by HiRISE under HiWish program The black strip is where data were not gathered. This image was named HiRISE Picture of the Day for June 25, 2024.]] The Eridania quadrangle is the location of [[Gullies on Mars|gullies]] that may be due to recent flowing water. Gullies occur on steep slopes, especially on the walls of craters. Gullies are believed to be relatively young because they have few, if any craters. Moreover, they lie on top of sand dunes which themselves are considered to be quite young. Usually, each gully has an alcove, channel, and apron. Some studies have found that gullies occur on slopes that face all directions,<ref>Edgett, K. et al. 2003. Polar-and middle-latitude martian gullies: A view from MGS MOC after 2 Mars years in the mapping orbit. Lunar Planet. Sci. 34. Abstract 1038.</ref> others have found that the greater number of gullies are found on poleward facing slopes, especially from 30-44 S.<ref name="planetary.brown.edu">{{cite web |url=https://www.planetary.brown.edu/pdfs/3138.pdf |title=Archived copy |archive-url=https://web.archive.org/web/20170706040142/http://planetary.brown.edu/pdfs/3138.pdf |archive-date=2017-07-06 |url-status=}}</ref><ref name="ReferenceA">{{cite journal | last1 = Dickson | first1 = J. | display-authors = etal | year = 2007 | title = Martian gullies in the southern mid-latitudes of Mars Evidence for climate-controlled formation of young fluvial features based upon local and global topography | journal = Icarus | volume = 188 | issue = 2| pages = 315–323 | doi=10.1016/j.icarus.2006.11.020 | bibcode=2007Icar..188..315D}}</ref>

Although many ideas have been put forward to explain them,<ref>{{Cite web|url=http://www.psrd.hawaii.edu/Aug03/MartianGullies.html|title = PSRD: Gullied Slopes on Mars}}</ref> the most popular involve liquid water coming from an [[aquifer]], from melting at the base of old [[glaciers]], or from the melting of ice in the ground when the climate was warmer.<ref>{{cite journal | last1 = Heldmann | first1 = J. | last2 = Mellon | first2 = M. | year = 2004| title = Observations of martian gullies and constraints on potential formation mechanisms. 2004 | url =https://zenodo.org/record/1259029 | journal = Icarus | volume = 168 | issue = 2| pages = 285–304 | doi=10.1016/j.icarus.2003.11.024 | bibcode=2004Icar..168..285H}}</ref><ref>Forget, F. et al. 2006. Planet Mars Story of Another World. Praxis Publishing. Chichester, UK.</ref> Because of the good possibility that liquid water was involved with their formation and that they could be very young, scientist believe gullies are where we may be able to find life.

There is evidence for all three theories. Most of the gully alcove heads occur at the same level, just as one would expect of an aquifer. Various measurements and calculations show that liquid water could exist in aquifers at the usual depths where gullies begin.<ref>{{cite journal | last1 = Heldmann | first1 = J. | last2 = Mellon | first2 = M. | year = 2004 | title = Observations of martian gullies and constraints on potential formation mechanisms | url = https://zenodo.org/record/1259029| journal = Icarus | volume = 168 | issue = 2| pages = 285–304 | doi=10.1016/j.icarus.2003.11.024 | bibcode=2004Icar..168..285H}}</ref> One variation of this model is that rising hot [[magma]] could have melted ice in the ground and caused water to flow in aquifers. Aquifers are layer that allow water to flow. They may consist of porous sandstone. The aquifer layer would be perched on top of another layer that prevents water from going down (in geological terms it would be called impermeable). Because water in an aquifer is prevented from going down, the only direction the trapped water can flow is horizontally. Eventually, water could flow out onto the surface when the aquifer reaches a break—like a crater wall. The resulting flow of water could erode the wall to create gullies.<ref>{{Cite web|url=http://www.space.com/scienceastronomy/mars_aquifer_041112.html|title = Mars Gullies Likely Formed by Underground Aquifers|website = [[Space.com]]|date = 12 November 2004}}</ref> Aquifers are quite common on Earth. A good example is "Weeping Rock" in [[Zion National Park]] [[Utah]].<ref>Harris, A and E. Tuttle. 1990. Geology of National Parks. Kendall/Hunt Publishing Company. Dubuque, Iowa</ref>

As for the next theory, much of the surface of Mars is covered by a thick smooth mantle that is thought to be a mixture of ice and dust.<ref>Malin, M. and K. Edgett. 2001. Mars Global Surveyor Mars Orbiter Camera: Interplanetary cruise through primary mission. J. Geophys. Res.: 106, 23429-23570</ref><ref>Mustard, J. et al. 2001. Evidence for recent climate change on Mars from the identification of youthful near-surface ground ice. Nature 412. 411-414.</ref><ref>{{cite journal | last1 = Carr | first1 = M | year = 2001 | title = Mars Global Surveyor observations of fretted terrain | journal = J. Geophys. Res. | volume = 106 | issue = E10| pages = 23571–23595 | doi=10.1029/2000je001316 | bibcode=2001JGR...10623571C}}</ref> This ice-rich mantle, a few yards thick, smooths the land, but in places it has a bumpy texture, resembling the surface of a basketball. The mantle may be like a glacier and under certain conditions the ice that is mixed in the mantle could melt and flow down the slopes and make gullies.<ref>[https://web.archive.org/web/20131224133733/http://www.nbcnews.com/id/15702457 NBC News]</ref><ref>{{cite journal | doi=10.1073/pnas.0803760105 | volume=105 | title=Formation of gullies on Mars: Link to recent climate history and insolation microenvironments implicate surface water flow origin | year=2008 | journal=Proceedings of the National Academy of Sciences | pages=13258–13263 | last1 = Head | first1 = J. W. | issue=36 | pmid=18725636 | pmc=2734344| bibcode=2008PNAS..10513258H | doi-access=free }}</ref><ref>{{cite journal | last1 = Head | first1 = J. | display-authors = etal | year = 2008 | title = Formation of gullies on Mars: Link to recent climate history and insolation microenvironments implicate surface water flow origin | journal = PNAS | volume = 105 | issue = 36| pages = 13258–13263 | doi=10.1073/pnas.0803760105 | pmid=18725636 | pmc=2734344| bibcode = 2008PNAS..10513258H | doi-access = free }}</ref> Because there are few craters on this mantle, the mantle is relatively young. An excellent view of this mantle is shown below in the picture of the Ptolemaeus Crater Rim, as seen by [[HiRISE]].<ref>{{cite journal | last1 = Christensen | first1 = P | year = 2003 | title = Formation of recent martian gullies through melting of extensive water-rich snow deposits | journal = Nature | volume = 422 | issue = 6927| pages = 45–48 | doi=10.1038/nature01436 | pmid=12594459| bibcode = 2003Natur.422...45C| s2cid = 4385806 }}</ref> The ice-rich mantle may be the result of climate changes.<ref>{{cite web| url = http://news.nationalgeographic.com/news/2008/03/080319-mars-gullies_2.html| url-status = dead| archive-url = https://web.archive.org/web/20080504022016/http://news.nationalgeographic.com/news/2008/03/080319-mars-gullies_2.html| archive-date = 2008-05-04| title = Melting Snow Created Mars Gullies, Expert Says}}</ref> Changes in Mars's orbit and tilt cause significant changes in the distribution of water ice from polar regions down to latitudes equivalent to Texas. During certain climate periods, water vapor leaves polar ice and enters the atmosphere. The water comes back to ground at lower latitudes as deposits of frost or snow mixed generously with dust. The atmosphere of Mars contains a great deal of fine dust particles. Water vapor will condense on the particles, then fall down to the ground due to the additional weight of the water coating. When Mars is at its greatest tilt or obliquity, up to 2&nbsp;cm of ice could be removed from the summer ice cap and deposited at midlatitudes. This movement of water could last for several thousand years and create a snow layer of up to around 10 meters thick.<ref>{{cite journal | last1 = Jakosky | first1 = B. | last2 = Carr | first2 = M. | year = 1985 | title = Possible precipitation of ice at low latitudes of Mars during periods of high obliquity | url = https://zenodo.org/record/1233025| journal = Nature | volume = 315 | issue = 6020| pages = 559–561 | doi=10.1038/315559a0 | bibcode=1985Natur.315..559J| s2cid = 4312172 }}</ref><ref>{{cite journal | last1 = Jakosky | first1 = B. | display-authors = etal | year = 1995 | title = Chaotic obliquity and the nature of the Martian climate | journal = J. Geophys. Res. | volume = 100 | issue = E1| pages = 1579–1584 | doi=10.1029/94je02801 | bibcode=1995JGR...100.1579J}}</ref> When ice at the top of the mantling layer goes back into the atmosphere, it leaves behind dust, which insulating the remaining ice.<ref>MLA NASA/Jet Propulsion Laboratory (2003, December 18). Mars May Be Emerging From An Ice Age. ScienceDaily. Retrieved February 19, 2009, from {{cite web| url = http://www.sciencedaily.com| title = ScienceDaily: Your source for the latest research news}} /releases/2003/12/031218075443.htmAds by GoogleAdvertise</ref> Measurements of altitudes and slopes of gullies support the idea that snowpacks or glaciers are associated with gullies. Steeper slopes have more shade which would preserve snow.<ref name="planetary.brown.edu"/><ref name="ReferenceA"/> Higher elevations have far fewer gullies because ice would tend to sublimate more in the thin air of the higher altitude.<ref>{{cite journal | last1 = Hecht | first1 = M | year = 2002 | title = Metastability of liquid water on Mars | journal = Icarus | volume = 156 | issue = 2| pages = 373–386 | doi=10.1006/icar.2001.6794 | bibcode=2002Icar..156..373H}}</ref>

The third theory might be possible since climate changes may be enough to simply allow ice in the ground to melt and thus form the gullies. During a warmer climate, the first few meters of ground could thaw and produce a "debris flow" similar to those on the dry and cold Greenland east coast.<ref>Peulvast, J. ''Physio-Geo.'' 18. 87-105.</ref> Since the gullies occur on steep slopes only a small decrease of the shear strength of the soil particles is needed to begin the flow. Small amounts of liquid water from melted ground ice could be enough.<ref>Costard, F. et al. 2001. Debris Flows on Mars: Analogy with Terrestrial Periglacial Environment and Climatic Implications. Lunar and Planetary Science XXXII (2001). 1534.pdf</ref><ref>http://www.spaceref.com:16090/news/viewpr.html?pid=7124{{dead link|date=September 2017 |bot=InternetArchiveBot |fix-attempted=yes }},</ref> Calculations show that a third of a mm of runoff can be produced each day for 50 days of each Martian year, even under current conditions.<ref>{{cite journal | last1 = Clow | first1 = G | year = 1987 | title = Generation of liquid water on Mars through the melting of a dusty snowpack | doi = 10.1016/0019-1035(87)90123-0 | journal = Icarus | volume = 72 | issue = 1| pages = 95–127 | bibcode=1987Icar...72...95C}}</ref>

== Dust devil tracks == Many areas on Mars, including Eridania, experience the passage of giant [[dust devils]]. A thin coating of fine bright dust covers most of the Martian surface. When a dust devil goes by it blows away the coating and exposes the underlying dark surface.

Dust devils occur when the sun warms up the air near a flat, dry surface. The warm air then rises quickly through the cooler air and begins spinning while moving ahead. This spinning, moving cell may pick up dust and sand then leave behind a clean surface.<ref>{{Cite web|url=http://hirise.lpl.arizona.edu/PSP_00481_2410|title = HiRISE &#124; (PSP_00481_2410)}}</ref>

Dust devils have been seen from the ground and high overhead from orbit. They have even blown the dust off of the [[solar panels]] of the two [[Mars Exploration Rover|Rovers]] on Mars, thereby greatly extending their lives.<ref>[http://marsrovers.jpl.nasa.gov/gallery/press/spirit/20070412a.html NASA.gov]</ref> The twin Rovers were designed to last for 3 months, instead they lasted more than six years, and one is still going after 8 years. The pattern of the tracks have been shown to change every few months.<ref>{{cite web|url=http://mars.jpl.nasa.gov/spotlight/KenEdgett.html |title=Mars Exploration: Features |access-date=2012-01-19 |url-status=dead |archive-url=https://web.archive.org/web/20111028015730/http://mars.jpl.nasa.gov/spotlight/kenEdgett.html |archive-date=2011-10-28 }}</ref>

A study that combined data from the [[High Resolution Stereo Camera]] (HRSC) and the [[Mars Orbiter Camera]] (MOC) found that some large dust devils on Mars have a diameter of 700 meters and last at least 26 minutes.<ref>{{cite journal | last1 = Reiss | first1 = D. | display-authors = etal | year = 2011 | title = Multitemporal observations of identical active dust devils on Mars with High Resolution Stereo Camera (HRSC) and Mars Orbiter Camera (MOC) | journal = Icarus | volume = 215 | issue = 1| pages = 358–369 | doi=10.1016/j.icarus.2011.06.011 | bibcode=2011Icar..215..358R}}</ref>

== Paleomagnetism == The [[Mars Global Surveyor]] (MGS) discovered magnetic stripes in the crust of Mars, especially in the Phaethontis and Eridania quadrangles ([[Terra Cimmeria]] and [[Terra Sirenum]]).<ref>Barlow, N. 2008. Mars: An Introduction to its Interior, Surface and Atmosphere. Cambridge University Press</ref><ref>{{Cite book|isbn = 978-0-387-48925-4|title = Planet Mars: Story of Another World|last1 = Forget|first1 = François|last2 = Costard|first2 = François|last3 = Lognonné|first3 = Philippe|date = 12 December 2007| publisher=Praxis }}</ref> The magnetometer on MGS discovered 100&nbsp;km wide stripes of magnetized crust running roughly parallel for up to 2000&nbsp;km. These stripes alternate in polarity with the north magnetic pole of one pointing up from the surface and the north magnetic pole of the next pointing down.<ref>{{Cite book|isbn = 978-0-521-82956-4|title = The Scientific Exploration of Mars|last1 = Taylor|first1 = Fredric W.|date = 10 December 2009| publisher=Cambridge University Press }}</ref> When similar stripes were discovered on Earth in the 1960s, they were taken as evidence of [[plate tectonics]]. Researchers believe these magnetic stripes on Mars are evidence for a short, early period of plate tectonic activity.<ref>{{Cite web|url=http://www.space.com/scienceastronomy/mars-plate-tectonics-recent-past-110103.html|title = Surface of Mars Possibly Shaped by Plate Tectonics in Recent Past|website = [[Space.com]]|date = 3 January 2011}}</ref> When the rocks became solid they retained the magnetism that existed at the time. A magnetic field of a planet is believed to be caused by fluid motions under the surface.<ref>Connerney, J. et al. 1999. Magnetic lineations in the ancient crust of Mars. Science: 284. 794-798.</ref><ref>Langlais, B. et al. 2004. Crustal magnetic field of Mars ''Journal of Geophysical Research'' 109: EO2008</ref><ref>{{cite journal | last1 = Connerney | first1 = J. | display-authors = etal | year = 2005 | title = Tectonic implications of Mars crustal magnetism | journal = Proceedings of the National Academy of Sciences of the USA | volume = 102 | issue = 42| pages = 14970–14975 | doi=10.1073/pnas.0507469102| pmc = 1250232 | pmid=16217034| bibcode = 2005PNAS..10214970C| doi-access = free }}</ref> However, there are some differences, between the magnetic stripes on Earth and those on Mars. The Martian stripes are wider, much more strongly magnetized, and do not appear to spread out from a middle crustal spreading zone. Because the area containing the magnetic stripes is about 4 billion years old, it is believed that the global magnetic field probably lasted for only the first few hundred million years of Mars' life, when the temperature of the molten iron in the planet's core might have been high enough to mix it into a magnetic dynamo. There are no magnetic fields near large impact basins like Hellas. The shock of the impact may have erased the remnant magnetization in the rock. So, magnetism produced by early fluid motion in the core would not have existed after the impacts.<ref>{{cite journal | last1 = Acuna | first1 = M. | display-authors = etal | year = 1999 | title = Global distribution of crustal magnetization discovered by the Mars Global Surveyor MAG/ER Experiment | url = https://zenodo.org/record/1231157| journal = Science | volume = 284 | issue = 5415| pages = 790–793 | doi=10.1126/science.284.5415.790| bibcode = 1999Sci...284..790A | pmid = 10221908 }}</ref>

Some researchers have proposed that early in its history Mars exhibited a form of plate tectonics. At about 3.93 billion years ago Mars became a one plate planet with a superplume under Tharsis.<ref>Baker, V., et al. 2017. THE WATERY ORIGIN AND EVOLUTION OF MARS: A GEOLOGICAL PERSPECTIVE. Lunar and Planetary Science XLVIII (2017). 3015.pdf</ref><ref>Baker, V. et al. 2004. TENTATIVE THEORIES FOR THE LONG-TERM GEOLOGICAL AND HYDROLOGICAL EVOLUTION OF MARS. Lunar and Planetary Science XXXV (2004) 1399.pdf.</ref><ref>Baker, V., et al. 2002. A THEORY FOR THE GEOLOGICAL EVOLUTION OF MARS AND RELATED SYNTHESIS (GEOMARS). Lunar and Planetary Science XXXIII (2002). 1586pdf.</ref>

When molten rock containing magnetic material, such as [[hematite]] (Fe<sub>2</sub>O<sub>3</sub>), cools and solidifies in the presence of a magnetic field, it becomes magnetized and takes on the polarity of the background field. This magnetism is lost only if the rock is subsequently heated above a particular temperature (the Curie point which is 770&nbsp;°C for iron). The magnetism left in rocks is a record of the magnetic field when the rock solidified.<ref>{{Cite web|url=http://sci.esa.int/science-e/www/object/index.cfm?fobjectid=31028&fbodylongid=645|title=ESA Science & Technology - Martian Interior}}</ref>

==Dunes== [[File:Wikihugginsdunesdevils.jpg|thumb|upright=1.2|Dunes and [[dust devil tracks]] on floor of Huggins Crater, as seen by CTX camera (on Mars Reconnaissance Orbiter). Dark streaks on dunes are dust devil tracks.]] Dunes, including barchans are present in the Eridania quadrangle and some pictures below. When there are perfect conditions for producing sand dunes, steady wind in one direction and just enough sand, a barchan sand dune forms. Barchans have a gentle slope on the wind side and a much steeper slope on the lee side where horns or a notch often forms.<ref name=Pye2008>{{cite book|last=Pye|first=Kenneth|title=Aeolian Sand and Sand Dunes|year=2008|publisher=Springer|isbn=9783540859109|pages=138|author2=Haim Tsoar}}</ref> The whole dune may appear to move with the wind. Observing dunes on Mars can tell us how strong the winds are, as well as their direction. If pictures are taken at regular intervals, one may see changes in the dunes or possibly in ripples on the dune’s surface. On Mars dunes are often dark in color because they were formed from the common, volcanic rock basalt. In the dry environment, dark minerals in basalt, like olivine and pyroxene, do not break down as they do on Earth. Although rare, some dark sand is found on Hawaii which also has many volcanoes discharging basalt. Barchan is a Russian term because this type of dune was first seen in the desert regions of Turkistan.<ref>{{Cite web|url=http://www.britannica.com/EBchecked/topic/53068/barchan|title = Barchan &#124; sand dune}}</ref> Some of the wind on Mars is created when the dry ice at the poles is heated in the spring. At that time, the solid carbon dioxide (dry ice) sublimates or changes directly to a gas and rushes away at high speeds. Each Martian year 30% of the carbon dioxide in the atmosphere freezes out and covers the pole that is experiencing winter, so there is a great potential for strong winds.<ref name="icarus169">{{cite journal|author1=Mellon, J. T. |author2=Feldman, W. C. |author3=Prettyman, T. H. |title=The presence and stability of ground ice in the southern hemisphere of Mars|journal=Icarus|year=2003|volume=169|issue=2|pages=324–340|bibcode=2004Icar..169..324M|doi=10.1016/j.icarus.2003.10.022}}</ref>

==Glacial features== {{main|Glaciers on Mars}} Glaciers, loosely defined as patches of currently or recently flowing ice, are thought to be present across large but restricted areas of the modern Martian surface, and are inferred to have been more widely distributed at times in the past.<ref name="Carr">"The Surface of Mars" Series: Cambridge Planetary Science (No. 6) {{ISBN|978-0-511-26688-1}} Michael H. Carr, United States Geological Survey, Menlo Park</ref><ref>Kieffer, H., et al. 1992. Mars. University of Arizona Press. Tucson. {{ISBN|0-8165-1257-4}}</ref>{{page needed|date=June 2017}} Lobate convex features on the surface known as '''viscous flow features''' and '''[[lobate debris aprons]]''', which show the characteristics of [[Non-Newtonian fluid|non-Newtonian flow]], are now almost unanimously regarded as true glaciers.<ref name="Carr" /><ref name="Milliken">{{cite journal | last1 = Milliken | first1 = R. E. | last2 = Mustard | first2 = J. F. | last3 = Goldsby | first3 = D. L. | year = 2003 | title = Viscous flow features on the surface of Mars: Observations from high-resolution Mars Orbiter Camera (MOC) images | journal = Journal of Geophysical Research | volume = 108 | issue = E6| page = 5057 | doi=10.1029/2002je002005 | bibcode=2003JGRE..108.5057M}}</ref><ref name="SquyresCarr">{{cite journal | last1 = Squyres | first1 = S.W. | last2 = Carr | first2 = M.H. | year = 1986 | title = Geomorphic evidence for the distribution of ground ice on Mars | url = https://zenodo.org/record/1230966| journal = Science | volume = 213 | issue = 4735| pages = 249–253 | doi = 10.1126/science.231.4735.249 | bibcode = 1986Sci...231..249S | pmid = 17769645 | s2cid = 34239136 }}</ref><ref name="Headetal2010">{{cite journal | last1 = Head | first1 = J.W. | last2 = Marchant | first2 = D.R. | last3 = Dickson | first3 = J.L. | last4 = Kress | first4 = A.M. | year = 2010 | title = Criteria for the recognition of debris-covered glacier and valley glacier landsystem deposits | journal = Earth Planet. Sci. Lett. | volume = 294 | issue = 3–4 | pages = 306–320 | doi=10.1016/j.epsl.2009.06.041 | bibcode=2010E&PSL.294..306H}}</ref><ref name="HoltetalSHARAD">{{cite journal | last1 = Holt | first1 = J.W. | display-authors = etal | year = 2008 | title = Radar sounding evidence for buried glaciers in the southern mid-latitudes of Mars | journal = Science | volume = 322 | issue = 5905| pages = 1235–1238 | doi=10.1126/science.1164246 | pmid=19023078| bibcode = 2008Sci...322.1235H | hdl = 11573/67950 | s2cid = 36614186 }}</ref><ref name="MorganetalDeuteronilus">{{cite journal | last1 = Morgan | first1 = G.A. | last2 = Head | first2 = J.W. | last3 = Marchant | first3 = D.R. | year = 2009 | title = Lineated valley fill (LVF) and lobate debris aprons (LDA) in the Deuteronilus Mensae northern dichotomy boundary region, Mars: Constraints on the extent, age and episodicity of Amazonian glacial events | journal = Icarus | volume = 202 | issue = 1| pages = 22–38 | doi=10.1016/j.icarus.2009.02.017 | bibcode=2009Icar..202...22M}}</ref><ref name="Plautetal">{{cite journal | last1 = Plaut | first1 = J.J. | last2 = Safaeinili | first2 = A. | last3 = Holt | first3 = J.W. | last4 = Phillips | first4 = R.J. | last5 = Head | first5 = J.W. | last6 = Sue | first6 = R. | last7 = Putzig | first7 = A. | year = 2009 | title = Frigeri Radar evidence for ice in lobate debris aprons in the mid-northern latitudes of Mars | journal = Geophys. Res. Lett. | volume = 36 | issue = 2| page = L02203 | doi=10.1029/2008gl036379 | bibcode=2009GeoRL..36.2203P| s2cid = 17530607 | doi-access = free }}</ref><ref name="Bakeretal2010">{{cite journal | last1 = Baker | first1 = D.M.H. | last2 = Head | first2 = J.W. | last3 = Marchant | first3 = D.R. | year = 2010 | title = Flow patterns of lobate debris aprons and lineated valley fill north of Ismeniae Fossae, Mars: Evidence for extensive mid-latitude glaciation in the Late Amazonian | journal = Icarus | volume = 207 | issue = 1| pages = 186–209 | doi=10.1016/j.icarus.2009.11.017 | bibcode=2010Icar..207..186B}}</ref><ref name="ArfstromHartmann">{{cite journal | last1 = Arfstrom | first1 = J. | year = 2005 | title = Terrestrial analogs and interrelationships | journal = Icarus | volume = 174 | issue = 2| pages = 321–335 | doi=10.1016/j.icarus.2004.05.026 | bibcode=2005Icar..174..321A}}</ref> Today, after years of observations, we consider lobate debris aprons (LDA's) and lineated valley fill (LVF) basically the same--mostly ice with a covering of debris, their shapes (and names) are dependent on their locations. When confined within a valley, LVF is present; in contrast when not confined, this flowing debris covered ice spreads out to form LDA's.<ref>Wueller, L., et al. 2025. Relationships between lobate debris aprons and lineated valley fill on Mars: Evidence for an extensive Amazonian valley glacial landsystem in Mamers Valles. Icarus. Volume 426, 15 116373</ref>

==Lake== {{see also|Lakes on Mars}} The Eridania Basin, located near 180 E and 30 South, is thought to have contained a large lake with a depth of 1&nbsp;km in places.<ref>{{cite journal | last1 = Irwin | first1 = R. | display-authors = etal | year = 2004| title = 2004 | doi = 10.1029/2004je002287 | journal = J. Geophys. Res. | volume = 109 | issue = E12| page = E12009 | bibcode=2004JGRE..10912009I| doi-access = free }}</ref> The basin is composed of a group of eroded and connected topographically impact basins. The lake has been estimated to have an area of 3,000,000 square kilometers. Water from this lake entered Ma'adim Vallis which starts at the lake's north boundary.<ref name="Michalski, J. 2015">Michalski, J., E. Noe Dobrea1, C. Weitz. 2015. Mg-rich clays and silica-bearing deposits in Eridania basin: Possible evidence for ancient sea deposits in Mars. 46th Lunar and Planetary Science Conference. 2754.pdf</ref> It is surrounded by valley networks that all end at the same elevation, suggesting that they emptied into a lake.<ref>Baker, D., J. Head. 2014. 44th LPSC, abstract #1252</ref> Magnesium-rich clay minerals and opaline silica have been detected in the area.<ref>{{cite journal | last1 = Cuadros | first1 = J. | display-authors = etal | year = 2013 | title = Crystal-chemistry of interstratified Mg/Fe-clay minerals from seafloor hydrothermal sites| url = https://archimer.ifremer.fr/doc/00160/27131/25329.pdf| journal = Chem. Geol. | volume = 360–361 | pages = 142–158 | doi=10.1016/j.chemgeo.2013.10.016| bibcode = 2013ChGeo.360..142C}}</ref> These minerals are consistent with the presence of a large lake.<ref name="Michalski, J. 2015"/>

<gallery class="center" widths="190px" heights="180px"> PIA22059 fig1eridaniadepths.jpg|Map showing estimated water depth in different parts of Eridania Sea. This map is about 530 miles across. PIA22059 fig1eridaniadepthslabeled.jpg|Features around Eridania Sea labeled </gallery>

The region of this lake shows strong evidence for ancient magnetism on Mars.<ref>{{cite journal | last1 = Connerney | first1 = J. | display-authors = etal | year = 2005 | title = Tectonic implications of Mars crustal magnetism | journal = Proc. Natl. Acad. Sci. USA | volume = 102 | issue = 42| pages = 14970–14975 | doi=10.1073/pnas.0507469102| pmc = 1250232 | pmid=16217034| bibcode = 2005PNAS..10214970C| doi-access = free }}</ref> It has been suggested that the crust was pulled apart here, as on [[plate boundaries]] on the Earth. There are high levels of [[potassium]] in the area which may point to a deep mantle source for volcanism or major changes in the crust.<ref>{{cite journal | last1 = Hahn | first1 = B. | display-authors = etal | year = 2011 | title = Martian surface heat production and crustal heat flow from Mars Odyssey Gamma-Ray spectrometry | journal = Geophys. Res. Lett. | volume = 38 | issue = 14| page = L14203 | doi=10.1029/2011gl047435 | bibcode=2011GeoRL..3814203H| doi-access = free }}</ref><ref>Staudigel, H. 2013. Treatise on Geochemistry 2nd edn, Vol. 4 (eds Holland, H. & Turekian, K.), 583–606.</ref><ref>{{cite journal | last1 = Taylor | first1 = G. | display-authors = etal | year = 2006 | title = Variations in K/Th on Mars | journal = J. Geophys. Res. | volume = 111 | issue = E3| pages = 1–20 | doi = 10.1029/2006JE002676 | bibcode=2006JGRE..111.3S06T| doi-access = free }}</ref>

Later research with CRISM found thick deposits, greater than 400 meters thick, that contained the minerals [[saponite]], talc-saponite, Fe-rich [[mica]] (for example, [[glauconite]]-[[nontronite]]), Fe- and Mg-serpentine, Mg-Fe-Ca-[[carbonate]] and probable Fe-[[sulphide]]. The Fe-sulphide probably formed in deep water from water heated by [[volcano]]es. Analyses from the ''[[Mars Reconnaissance Orbiter]]'' provided evidence of ancient hydrothermal seafloor deposits in Eridania basin, suggesting that [[hydrothermal vent]]s pumped mineral-laden water directly into this ancient Martian lake.<ref>[https://www.jpl.nasa.gov/news/news.php?feature=6966 Mars Study Yields Clues to Possible Cradle of Life]. NASA News, 6 October 2017.</ref><ref>{{cite journal| pmc=5508135 | pmid=28691699 | doi=10.1038/ncomms15978 | volume=8 | title=Ancient hydrothermal seafloor deposits in Eridania basin on Mars | year=2017 | journal=Nat Commun | article-number=15978 | last1 = Michalski | first1 = JR | last2 = Dobrea | first2 = EZN | last3 = Niles | first3 = PB | last4 = Cuadros | first4 = J| bibcode=2017NatCo...815978M }}</ref> Some sources say clay deposits can be up to 2 km thick.<ref>Morden, S. 2022. The Red Planet. Pegasus Books. New York.</ref>

==Latitude dependent mantle== [[File:2509mantlelayers.jpg|thumb|upright=1.2|Mantle layers, as seen by HiRISE under HiWish program]] Much of the Martian surface is covered with a thick ice-rich, mantle layer that has fallen from the sky a number of times in the past.<ref>{{cite journal | last1 = Hecht | first1 = M | year = 2002 | title = Metastability of water on Mars | journal = Icarus | volume = 156 | issue = 2 | pages = 373–386 | doi=10.1006/icar.2001.6794 | bibcode=2002Icar..156..373H}}</ref><ref>{{cite journal | last1 = Mustard | first1 = J. | display-authors = etal | year = 2001 | title = Evidence for recent climate change on Mars from the identification of youthful near-surface ground ice | journal = Nature | volume = 412 | issue = 6845| pages = 411–414 | doi=10.1038/35086515 | pmid=11473309 | bibcode = 2001Natur.412..411M| s2cid = 4409161 }}</ref><ref>{{cite journal | last1 = Pollack | first1 = J. | last2 = Colburn | first2 = D. | last3 = Flaser | first3 = F. | last4 = Kahn | first4 = R. | last5 = Carson | first5 = C. | last6 = Pidek | first6 = D. | year = 1979 | title = Properties and effects of dust suspended in the martian atmosphere | journal = J. Geophys. Res. | volume = 84 | pages = 2929–2945 | doi=10.1029/jb084ib06p02929 | bibcode=1979JGR....84.2929P}}</ref> In some places a number of layers are visible in the mantle.<ref>{{Cite web|url=http://www.uahirise.org/ESP_048897_2125|title=HiRISE &#124; Layered Mantling Deposits in the Northern Mid-Latitudes (ESP_048897_2125)}}</ref> Some surfaces in Eridania are covered with this ice-rich mantling unit. In some places the surface displays a pitted or dissected texture; these textures are suggestive of material that once held ice that has since disappeared allowing the remaining soil to collapse into the subsurface.<ref>{{Cite web|url=http://hirise.lpl.arizona.edu/PSP_006736_1325|title=HiRISE &#124; Mantled Craters in Terra Cimmeria (PSP_006736_1325)}}</ref>

==Channels== There is enormous evidence that water once flowed in river valleys on Mars.<ref>{{cite journal | last1 = Baker | first1 = V. | display-authors = etal | year = 2015 | title = Fluvial geomorphology on Earth-like planetary surfaces: a review | journal = Geomorphology | volume = 245 | pages = 149–182 | doi=10.1016/j.geomorph.2015.05.002| pmc = 5701759 | pmid=29176917| bibcode = 2015Geomo.245..149B }}</ref><ref>Carr, M. 1996. in Water on Mars. Oxford Univ. Press.</ref> Images of curved channels have been seen in images from Mars spacecraft dating back to the early 1970s with the [[Mariner 9]] orbiter.<ref>Baker, V. 1982. The Channels of Mars. Univ. of Tex. Press, Austin, TX</ref><ref>{{cite journal | last1 = Baker | first1 = V. | last2 = Strom | first2 = R. | last3 = Gulick | first3 = V. | last4 = Kargel | first4 = J. | last5 = Komatsu | first5 = G. | last6 = Kale | first6 = V. | year = 1991 | title = Ancient oceans, ice sheets and the hydrological cycle on Mars | journal = Nature | volume = 352 | issue = 6336| pages = 589–594 | doi=10.1038/352589a0| bibcode = 1991Natur.352..589B | s2cid = 4321529 }}</ref><ref>{{cite journal | last1 = Carr | first1 = M | year = 1979 | title = Formation of Martian flood features by release of water from confined aquifers | journal = J. Geophys. Res. | volume = 84 | pages = 2995–300 | doi=10.1029/jb084ib06p02995 | bibcode=1979JGR....84.2995C}}</ref><ref>{{cite journal | last1 = Komar | first1 = P | year = 1979 | title = Comparisons of the hydraulics of water flows in Martian outflow channels with flows of similar scale on Earth | journal = Icarus | volume = 37 | issue = 1| pages = 156–181 | doi=10.1016/0019-1035(79)90123-4 | bibcode=1979Icar...37..156K}}</ref> Indeed, a study published in June 2017, calculated that the volume of water needed to carve all the channels on Mars was even larger than the proposed ocean that the planet may have had. Water was probably recycled many times from the ocean to rainfall around Mars.<ref>{{Cite web|url=http://spaceref.com/mars/how-much-water-was-needed-to-carve-valleys-on-mars.html|title=How Much Water Was Needed to Carve Valleys on Mars? - SpaceRef|date=5 June 2017}}{{Dead link|date=March 2024 |bot=InternetArchiveBot |fix-attempted=yes }}</ref><ref>{{cite journal | last1 = Luo | first1 = W. | display-authors = etal | year = 2017 | title = New Martian valley network volume estimate consistent with ancient ocean and warm and wet climate | journal = Nature Communications | volume = 8 | article-number = 15766 | doi = 10.1038/ncomms15766 | bibcode = 2017NatCo...815766L | pmc = 5465386 | pmid=28580943}}</ref>

==See also== {{div col|colwidth=30em}} * [[Barchan]] * [[Dust devil tracks]] * [[Eridania Lake]] * [[Eridania Planitia]] * [[Glaciers]] * [[Glaciers on Mars]] * [[HiRISE]] * [[Latitude dependent mantle]] * [[Lakes on Mars]] * [[Martian Gullies]] * [[MOC Public Targeting Program]] {{div col end}}

== References == {{reflist|colwidth=30em}}

==Further reading== * Lorenz, R. 2014. The Dune Whisperers. The Planetary Report: 34, 1, 8-14 * Lorenz, R., J. Zimbelman. 2014. Dune Worlds: How Windblown Sand Shapes Planetary Landscapes. Springer Praxis Books / Geophysical Sciences.

==External links== {{commons category|Eridania quadrangle}} * [http://www.psrd.hawaii.edu/Aug03/MartianGullies.html General review of many of the theories involving the origin of gullies.] * [https://www.planetary.brown.edu/pdfs/3138.pdf Good review of the history of the discovery of gullies.] {{Webarchive|url=https://web.archive.org/web/20170706040142/http://planetary.brown.edu/pdfs/3138.pdf |date=2017-07-06 }} * [https://www.youtube.com/watch?v=_sUUKcZaTgA Martian Ice - Jim Secosky - 16th Annual International Mars Society Convention] {{Mars quadrangle layout}} {{Mars}} {{Portal bar|Solar System}}

[[Category:Eridania quadrangle| ]] [[Category:Mars]]