{{Short description|Map of Mars}} {{Infobox feature on celestial object |name = Mare Boreum [[quadrangle (geography)|quadrangle]] |image = [[File:USGS-Mars-MC-1-MareBoreumRegion-mola.png|300px]] |caption = Map of Mare Boreum quadrangle from [[Mars Orbiter Laser Altimeter]] (MOLA) data. The highest elevations are red and the lowest are blue. |coordinates = {{coord|75|N|0|E|globe:mars_type:landmark|display=inline,title}} }} [[File:Mars NPArea-PIA00161.jpg|thumb|Image of the Mare Boreum Quadrangle (MC-1). The region includes the [[Martian polar ice caps|North Polar ice cap]], [[Korolev (Martian crater)|Korolev crater]] and [[Chasma Boreale]].]] The '''Mare Boreum 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 Mare Boreum [[Quadrangle (geography)|quadrangle]] is also referred to as '''MC-1''' (Mars Chart-1).<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> Its name derives from an older name for a feature that is now called [[Planum Boreum]], a large plain surrounding the polar cap.<ref>Patrick Moore and Robin Rees, ed. ''Patrick Moore's Data Book of Astronomy'' (Cambridge University Press, 2011), p. 130.</ref>
The quadrangle covers all of the Martian surface north of latitude 65°. It includes the [[Martian polar ice caps|north polar ice cap]], which has a swirl pattern and is roughly {{convert|1100|km|mi|abbr=off}} across. [[Mariner 9]] in 1972 discovered a belt of sand dunes that ring the polar ice deposits, which is {{convert|500|km|mi|abbr=off}} across in some places and may be the largest dune field in the Solar System.<ref>Hartmann, W. 2003. ''A Traveler's Guide to Mars''. Workman Publishing. NY NY.</ref> The ice cap is surrounded by the vast plains of [[Planum Boreum]] and [[Vastitas Borealis]]. Close to the pole, there is a large valley, [[Chasma Boreale]], that may have been formed from water melting from the ice cap.<ref>Clifford, S. 1987. Polar basal melting on Mars. J. Geophys. Res. 92: 9135-9152.</ref> An alternative view is that it was made by winds coming off the cold pole.<ref>Howard, A. 2000. The role of eolian processes in forming surface features of the martian polar layered deposits. Icarus. 144: 267-288.</ref><ref>Edgett, K. et al. 2003. Mars landscape evolution: influence of stratigraphy on geomorphology of the north polar region. Geomorphology. 52: 289-298.</ref> Another prominent feature is a smooth rise, formerly called Olympia Planitia. In the summer, a dark collar around the residual cap becomes visible; it is mostly caused by dunes.<ref name="Carr2006">{{cite book|author=Michael H. Carr|title=The surface of Mars|url=https://books.google.com/books?id=uLHlJ6sjohwC|access-date=21 March 2011|year=2006|publisher=Cambridge University Press|isbn=978-0-521-87201-0}}</ref> The quadrangle includes some very large craters that stand out in the north because the area is smooth with little change in topography. These large craters are [[Lomonosov (Martian crater)|Lomonosov]] and [[Korolev (Martian crater)|Korolev]]. Although smaller, the crater [[Stokes (crater on Mars)|Stokes]] is also prominent.
The ''[[Phoenix (spacecraft)|Phoenix]]'' lander landed on [[Vastitas Borealis]] within the Mare Boreum quadrangle at 68.218830° N and 234.250778° E on May 25, 2008.<ref>{{cite web | last = Lakdawalla | first = Emily | title = Phoenix Sol 2 press conference, in a nutshell | work = The Planetary Society weblog | publisher = [[Planetary Society]] | date = 2008-05-27 | url = http://planetary.org/blog/article/00001470/ | access-date = 2008-06-04 | archive-date = 2014-04-22 | archive-url = https://web.archive.org/web/20140422150353/http://www.planetary.org/blogs/emily-lakdawalla/2008/1470.html | url-status = dead }}</ref> The probe collected and analyzed soil samples in an effort to detect water and determine how hospitable the planet might once have been for life to grow. It remained active there until winter conditions became too harsh around five months later.<ref>{{cite web|url=https://www.newscientist.com/article/dn13661-mars-lander-aims-for-touchdown-in-green-valley.html|title=Mars lander aims for touchdown in 'Green Valley'|publisher=[[New Scientist]] Space|access-date=2008-04-14}}</ref>
After the mission ended the journal ''Science'' reported that chloride, bicarbonate, magnesium, sodium potassium, calcium, and possibly sulfate were detected in the samples analyzed by ''Phoenix''. The pH was narrowed down to 7.7±0.5. Perchlorate (ClO<sub>4</sub>), a strong oxidizer at elevated temperatures, was detected. This was a significant discovery because the chemical has the potential of being used for rocket fuel and as a source of oxygen for future colonists. Also, under certain conditions perchlorate can inhibit life; however some microorganisms obtain energy from the substance (by anaerobic reduction). The chemical when mixed with water can greatly lower freezing points, in a manner similar to how salt is applied to roads to melt ice. So, perchlorate may be allowing small amounts of liquid water to form on Mars today. Gullies, which are common in certain areas of Mars, may have formed from perchlorate melting ice and causing water to erode soil on steep slopes.<ref>Hecht, M. et al. 2009. Detection of Perchlorate and the Soluble Chemistry of Martian Soil at the Phoenix Lander Site. ''Science'': 325. 64–67</ref>
Much direct evidence was found for water at this location.<ref>Smith, P., et al. 2009. H<sub>2</sub>O at the Phoenix Landing Site. ''Science'': 325, 58-61.</ref>
==Freezing of atmosphere== Research based on slight changes in the orbits of spacecraft around Mars over 16 years found that when one hemisphere experiences winter, approximately 3 trillion to 4 trillion tons of carbon dioxide freezes out of the atmosphere onto the northern and southern polar caps. This represents 12 to 16 percent of the mass of the entire Martian atmosphere. These observation support predictions from the Mars Global Reference Atmospheric Model—2010.<ref>NASA/Goddard Space Flight Center. "New gravity map gives best view yet inside Mars." ScienceDaily. ScienceDaily, 21 March 2016. <https://www.sciencedaily.com/releases/2016/03/160321154013.htm>.</ref><ref>Antonio Genova, Sander Goossens, Frank G. Lemoine, Erwan Mazarico, Gregory A. Neumann, David E. Smith, Maria T. Zuber. Seasonal and static gravity field of Mars from MGS, Mars Odyssey and MRO radio science. ''Icarus'', 2016; 272: 228 DOI: 10.1016/j.icarus.2016.02.05</ref>
==Proof for ocean== Strong evidence for a one time ancient ocean was found in Mare Boreum near the north pole (as well as the south pole). In March 2015, a team of scientists published results showing that this region was highly enriched with deuterium, heavy hydrogen, by seven times as much as the Earth. This means that Mars has lost a volume of water 6.5 times what is stored in today's polar caps. The water for a time would have formed an ocean in the low-lying Mare Boreum. The amount of water could have covered the planet about 140 meters, but was probably in an ocean that in places would be almost 1 mile deep.
This international team used ESO's Very Large Telescope, along with instruments at the W. M. Keck Observatory and the NASA Infrared Telescope Facility, to map out different forms of water in Mars's atmosphere over a six-year period.<ref>{{Cite web|url=https://www.sciencedaily.com/releases/2015/03/150305140447.htm|title = Mars: The planet that lost an ocean's worth of water}}</ref><ref>. Villanueva, L., Mumma, R. Novak, H. Käufl, P. Hartogh, [[Thérèse Encrenaz|T. Encrenaz]], A. Tokunaga, A. Khayat, M. Smith. Strong water isotopic anomalies in the martian atmosphere: Probing current and ancient reservoirs. Science, 2015 DOI: 10.1126/science.aaa3630</ref>
==Ice cap== [[File:ESP 054515 2595icecaplayers.jpg|thumb|upright|Layers exposed in northern ice cap, as seen by [[HiRISE]] under [[HiWish program]]]] From observations with the Shallow Radar instrument (SHARAD) onboard the Mars Reconnaissance Orbiter, researchers determined that the total volume of water ice in the northern ice cap is {{Convert|821000|km3|sp=us}}. That is equal to 30% of the Earth's Greenland ice sheet, or enough to cover the surface of Mars to a depth of 5.6 meters<ref>{{Cite web|url=http://www.spaceref.com/news/viewpr.html?pid=29211|title = Radar Map of Buried Mars Layers Matches Climate Cycles| date=22 September 2009 }}</ref><ref>{{Cite web|url=http://spaceref.com/onorbit/radar-map-of-buried-mars-layers-matches-climate-cycles.html|title=Radar Map of Buried Mars Layers Matches Climate Cycles - SpaceRef|date=24 May 2013|access-date=26 April 2018|archive-date=22 April 2014|archive-url=https://archive.today/20140422103102/http://spaceref.com/onorbit/radar-map-of-buried-mars-layers-matches-climate-cycles.html|url-status=dead}}</ref><ref>{{Cite web|url=https://mars.nasa.gov/news/371/radar-map-of-mars-layers-matches-climate-cycles/|title = Radar Map of Mars Layers Matches Climate Cycles}}</ref>
==Dunes== Sand [[dunes]] have been found in many places on Mars. The presence of dunes shows that the planet has an atmosphere with wind, for dunes require wind to pile up the sand. Most dunes on Mars are black because of the weathering of the volcanic rock [[basalt]].<ref>{{Cite web|url=http://hirise.lpl.arizona.edu/ESP_016459_1830|title=HiRISE | Dunes and Inverted Craters in Arabia Terra (ESP_016459_1830)}}</ref><ref name="Carr2006"/> Black sand can be found on Earth on [[Hawaii]] and on some tropical South Pacific islands.<ref>{{Cite web|url=https://www.desertusa.com/desert-activity/sand-dune-wind1.html|title = Sand Dunes - Phenomena of the Wind - DesertUSA}}</ref> Sand is common on Mars due to the old age of the surface that has allowed rocks to erode into sand. Dunes on Mars have been observed to move many meters.<ref>Archived at [https://ghostarchive.org/varchive/youtube/20211205/ur_TeOs3S64 Ghostarchive]{{cbignore}} and the [https://web.archive.org/web/20151216133913/https://www.youtube.com/watch?v=ur_TeOs3S64 Wayback Machine]{{cbignore}}: {{cite web| url = https://www.youtube.com/watch?v=ur_TeOs3S64| title = Curiosity Rover Report (Dec. 15, 2015): First Visit to Martian Dunes | website=[[YouTube]]| date = 15 December 2015 }}{{cbignore}}</ref><ref>{{Cite web|url=https://uanews.arizona.edu/story/the-flowing-sands-of-mars|title = The Flowing Sands of Mars|date = 9 May 2012}}</ref> In this process, sand moves up the windward side and then falls down the leeward side of the dune, thus caused the dune to go toward the leeward side (or slip face).<ref>Namowitz, S., Stone, D. 1975. earth science the world we live in. American Book Company. New York.</ref> When images are enlarged, some dunes on Mars display ripples on their surfaces.<ref>{{Cite web|url=https://www.jpl.nasa.gov/news/news.php?feature=6551|title=NASA Rover's Sand-Dune Studies Yield Surprise|website=[[Jet Propulsion Laboratory]]}}</ref> These are caused by sand grains rolling and bouncing up the windward surface of a dune. The bouncing grains tend to land on the windward side of each ripple. The grains do not bounce very high so it does not take much to stop them.
== See also == {{div col|colwidth=30em}} * [[Climate of Mars]] * [[HiRISE]] * [[Impact crater]] * [[List of quadrangles on Mars]] * [[Patterned ground]] * ''[[Phoenix Spacecraft|Phoenix]]'' spacecraft * [[Martian polar ice caps]] * [[Vastitas Borealis]] * [[Water on Mars]] {{div col end}}
== References == {{reflist|colwidth=30em}}
== External links == {{commons category|Mare Boreum quadrangle}} {{Mars quadrangle layout}} {{Mars}} {{Portal bar|Solar System}}
{{DEFAULTSORT:Mare Boreum Quadrangle}} [[Category:Mare Boreum quadrangle| ]] [[Category:Mars]]