Mare Tyrrhenum quadrangle - Revision history

Suitupshowup at 14:14, 24 January 2025

2025-01-24T14:14:25Z

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	\|[[Mars Atlas\|Atlas]]		\|[[Mars Atlas\|Atlas]]
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			In this article, some of the best pictures from a number of spacecraft will show what the landscape looks like in this region. The origins and significance of all features will be explained as they are currently understood.

	<gallery widths="400" heights="300">		<gallery widths="400" heights="300">
	File:USGS-Mars-MC-22-MareTyrrhenumRegion-mola.png		File:USGS-Mars-MC-22-MareTyrrhenumRegion-mola.png

Suitupshowup: added image

2024-12-27T23:15:31Z

added image

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	File:PIA00182-MC-22-MareTyrrhenumRegion-19980605.jpg		File:PIA00182-MC-22-MareTyrrhenumRegion-19980605.jpg
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			[[File:Collage tyrrhenum 01.jpg\|Features of Features of Mare Tyrrhenum quadrangle, as seen by HiRISE under under HiWish program\|600pxr\| Features of Mare Tyrrhenum quadrangle]]

			Scenes of the Mare Tyrrhenum quadrangle


	The Mare Tyrrhenum quadrangle contains a rich variety of features that include one of the planet’s oldest volcanoes, and many of the usual beautiful landscapes on the planet such as columnar jointing, craters, dunes, ridge networks, and even a landslide. In this article, some of the best pictures from a number of spacecraft will show what the landscape looks like in this region. The origins and significance of all features will be explained as they are currently understood.		The Mare Tyrrhenum quadrangle contains a rich variety of features that include one of the planet’s oldest volcanoes, and many of the usual beautiful landscapes on the planet such as columnar jointing, craters, dunes, ridge networks, and even a landslide. In this article, some of the best pictures from a number of spacecraft will show what the landscape looks like in this region. The origins and significance of all features will be explained as they are currently understood.

Suitupshowup: /* Other views in Mare Tyrrhenum quadrangle */

2023-12-24T22:55:23Z

Other views in Mare Tyrrhenum quadrangle

← Older revision		Revision as of 23:55, 24 December 2023
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	[[File: ESP 056726 1695ejectalobes.jpg\|Ejecta lobes indicated with arrows in a crater]]		[[File: ESP 056726 1695ejectalobes.jpg\|Ejecta lobes indicated with arrows in a crater]]
	Ejecta lobes indicated with arrows in a crater		Ejecta lobes indicated with arrows in a crater

	==See also==		==See also==

Suitupshowup: /* Columnar Jointing */

2023-12-24T22:54:32Z

Columnar Jointing

← Older revision		Revision as of 23:54, 24 December 2023
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	</gallery>		</gallery>
	[[File: 14016 1945columnarjointing.jpg\|600pxr\|Close view of crater wall with columnar jointing labeled]]		[[File: 14016 1945columnarjointing.jpg\|600pxr\|Close view of crater wall with columnar jointing labeled]]
	Close view of crater wall with columnar jointing labeled		Close view of crater wall with columnar jointing labeled

	<gallery class="center" widths="380px" heights="360px">		<gallery class="center" widths="380px" heights="360px">

Michel Lamontagne at 16:48, 16 November 2020

2020-11-16T16:48:01Z

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			{{Mars atlas}}
	{\| class="wikitable sortable"		{\| class="wikitable sortable"
	\|MC-22		\|MC-22

Suitupandshowup: /* Other views in Mare Tyrrhenum quadrangle */

2020-03-26T15:37:35Z

Other views in Mare Tyrrhenum quadrangle

← Older revision		Revision as of 16:37, 26 March 2020
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	<gallery class="center" widths="380px" heights="360px">		<gallery class="center" widths="380px" heights="360px">

	Image:Mare Tyrrhenum map.JPG\|Viking map of Mare Tyrrhenum quadrangle showing some major features. The small colored rectangles represent areas imaged in high resolution with camera on [[Mars Global Surveyor]].

Suitupandshowup: /* Other views in Mare Tyrrhenum quadrangle */

2020-03-26T15:37:02Z

Other views in Mare Tyrrhenum quadrangle

← Older revision		Revision as of 16:37, 26 March 2020
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	==Other views in Mare Tyrrhenum quadrangle==		==Other views in Mare Tyrrhenum quadrangle==

	[[File: ~~Tyrrhena Patera~~.JPG\|600pxr\|Viking map of Mare Tyrrhenum quadrangle showing some major features. The small colored rectangles represent areas imaged in high resolution with camera on [[Mars Global Surveyor]].]]		[[File: Mare Tyrrhenum map.JPG\|600pxr\|Viking map of Mare Tyrrhenum quadrangle showing some major features. The small colored rectangles represent areas imaged in high resolution with camera on [[Mars Global Surveyor]].]]

	Viking map of Mare Tyrrhenum quadrangle showing some major features. The small colored rectangles represent areas imaged in high resolution with camera on [[Mars Global Surveyor]].		Viking map of Mare Tyrrhenum quadrangle showing some major features. The small colored rectangles represent areas imaged in high resolution with camera on [[Mars Global Surveyor]].

Suitupandshowup: /* Other views in Mare Tyrrhenum quadrangle */

2020-03-26T15:35:50Z

Other views in Mare Tyrrhenum quadrangle

← Older revision		Revision as of 16:35, 26 March 2020
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	==Other views in Mare Tyrrhenum quadrangle==		==Other views in Mare Tyrrhenum quadrangle==

	[[File: Tyrrhena Patera.JPG\|600pxr\|Viking map of Mare Tyrrhenum quadrangle showing some major features. The small colored rectangles represent areas imaged in high resolution with camera on [[Mars Global Surveyor]].		[[File: Tyrrhena Patera.JPG\|600pxr\|Viking map of Mare Tyrrhenum quadrangle showing some major features. The small colored rectangles represent areas imaged in high resolution with camera on [[Mars Global Surveyor]].]]

	Viking map of Mare Tyrrhenum quadrangle showing some major features. The small colored rectangles represent areas imaged in high resolution with camera on [[Mars Global Surveyor]].		Viking map of Mare Tyrrhenum quadrangle showing some major features. The small colored rectangles represent areas imaged in high resolution with camera on [[Mars Global Surveyor]].

Suitupandshowup at 15:35, 26 March 2020

2020-03-26T15:35:16Z

← Older revision		Revision as of 16:35, 26 March 2020
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	<gallery class="center" widths="380px" heights="360px">		<gallery class="center" widths="380px" heights="360px">

	ESP 045822 1680dunes.jpg\|Dunes~~, as seen by HiRISE under [[HiWish program]]~~		ESP 045822 1680dunes.jpg\|Dunes
	45822 1680dunesclose.jpg\|Close view of dunes		45822 1680dunesclose.jpg\|Close view of dunes

	ESP 052639 1680dunes.jpg\|Dunes		ESP 052639 1680dunes.jpg\|Dunes
	52639 1680dunes.jpg\|Close view of dunes, as seen by HiRISE under HiWish program		52639 1680dunes.jpg\|Close view of dunes, as seen by HiRISE under [[HiWish program]]

	File:ESP 054774 1700dunes.jpg\|Wide view of dunes among small craters		File:ESP 054774 1700dunes.jpg\|Wide view of dunes among small craters
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	<gallery class="center" widths="380px" heights="360px">		<gallery class="center" widths="380px" heights="360px">
	Image:Parana traps.JPG\|Columnar jointing on the Earth.		Image:Parana traps.JPG\|Columnar jointing on the Earth

	Image:Sounkyo 01 a.jpg\|Columnar jointing on the Earth.		Image:Sounkyo 01 a.jpg\|Columnar jointing on the Earth along highway

	Image:Columnar Jointing in Yellowstone.JPG\|Columnar Jointing in Yellowstone National Park.		Image:Columnar Jointing in Yellowstone.JPG\|Columnar Jointing in Yellowstone National Park.
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	==Other views in Mare Tyrrhenum quadrangle==		==Other views in Mare Tyrrhenum quadrangle==

			[[File: Tyrrhena Patera.JPG\|600pxr\|Viking map of Mare Tyrrhenum quadrangle showing some major features. The small colored rectangles represent areas imaged in high resolution with camera on [[Mars Global Surveyor]].

			Viking map of Mare Tyrrhenum quadrangle showing some major features. The small colored rectangles represent areas imaged in high resolution with camera on [[Mars Global Surveyor]].


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			<gallery class="center" widths="380px" heights="360px">

	~~<gallery class="center" widths="380px" heights="360px">~~		Image:Mare Tyrrhenum map.JPG\|Viking map of Mare Tyrrhenum quadrangle showing some major features. The small colored rectangles represent areas imaged in high resolution with camera on [[Mars Global Surveyor]].
	Image:Mare Tyrrhenum map.JPG\|Viking map of Mare Tyrrhenum quadrangle showing some major features. The small colored rectangles represent areas imaged in high resolution with camera on [[Mars Global Surveyor]]. ~~Tyrrhenus Mons is a major volcano.~~


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	File:ESP 055026 1590landslide.jpg\|Landslide		File:ESP 055026 1590landslide.jpg\|Landslide

	File:ESP 057584 1730fractures.jpg\|Fractured crater floor~~, as seen by HiRISE under HiWish program~~		File:ESP 057584 1730fractures.jpg\|Fractured crater floor
	</gallery>		</gallery>

Suitupandshowup at 15:14, 26 March 2020

2020-03-26T15:14:21Z

← Older revision		Revision as of 16:14, 26 March 2020
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	The crater Auki shows ridge networks that some researchers believe to be evidence of hydrothermal processes that occurred after impact. Impacts fracture rock and create enormous amounts of heat. On Mars, this heat can cause ice to melt and then force the resulting water to move through cracks that were generated during impact. This water will eventually deposit minerals. Mineral deposits may become evident when surrounding ground erodes. Deposits formed in this manner are more resistant to erosion.		The crater Auki shows ridge networks that some researchers believe to be evidence of hydrothermal processes that occurred after impact. Impacts fracture rock and create enormous amounts of heat. On Mars, this heat can cause ice to melt and then force the resulting water to move through cracks that were generated during impact. This water will eventually deposit minerals. Mineral deposits may become evident when surrounding ground erodes. Deposits formed in this manner are more resistant to erosion.
	Researchers have speculated that these hydrothermal effects should be common on Mars.<ref>Osinski, G., et al. 2013. Impact-generated hydrothermal systems on Earth and Mars. Icarus: 224, 347-363.</ref> Ridges found in and around the center of Auki are evidence of hydrothermal processes. This crater contains ridges that may have been produced after fractures formed ~~with~~ an impact. Using instruments on the [[Mars Reconnaissance Orbiter]] they found the minerals smectite (clay), silica, zeolite, serpentine, carbonate, and chlorite that are common in impact-induced hydrothermal systems on Earth.<ref>Carrozzo, F. et al. 2017. Geology and mineralogy of the Auki Crater, Tyrrhena Terra, Mars: A possible post impact-induced hydrothermal system. 281: 228-239</ref> <ref>Loizeau, D. et al. 2012. Characterization of hydrated silicate-bearing outcrops in tyrrhena Terra, Mars: implications to the alteration history of Mars. Icarus: 219, 476-497.</ref> <ref>Naumov, M. 2005. Principal features of impact-generated hydrothermal circulation systems: mineralogical and geochemical evidence. Geofluids: 5, 165-184.</ref> <ref>Ehlmann, B., et al. 2011. Evidence for low-grade metamorphism, hydrothermal alteration, and diagenesis on Mars from phyllosilicate mineral assemblages. Clays Clay Miner: 59, 359-377.</ref> <ref>Osinski, G. et al. 2013. Impact-generated hydrothermal systems on Earth and Mars. Icarus: 224, 347-363.</ref> <ref>Schwenzer, S., D. Kring. 2013. Alteration minerals in impact-generated hydrothermal systems – Exploring host rock variability. Icarus: 226, 487-496.</ref> Evidence of other hydrothermal systems around craters other than Auki has been found by different groups of scientists.<ref>Marzo, G., et al. 2010. Evidence for hesperian impact-induced hydrothermalism on Mars. Icarus: 667-683.</ref> <ref>Mangold, N., et al. 2012. Hydrothermal alteration in a late hesperian impact crater on Mars. 43rd Lunar and Planetary Science. #1209.</ref> <ref>Tornabene, L., et al. 2009. Parautochthonous megabreccias and possible evidence of impact-induced hydrothermal alteration in holden crater, Mars. 40th LPSC. #1766.</ref>		Researchers have speculated that these hydrothermal effects should be common on Mars.<ref>Osinski, G., et al. 2013. Impact-generated hydrothermal systems on Earth and Mars. Icarus: 224, 347-363.</ref> Ridges found in and around the center of Auki are evidence of hydrothermal processes. This crater contains ridges that may have been produced after fractures formed as a result of an impact. Using instruments on the [[Mars Reconnaissance Orbiter]] they found the minerals smectite (clay), silica, zeolite, serpentine, carbonate, and chlorite that are common in impact-induced hydrothermal systems on Earth.<ref>Carrozzo, F. et al. 2017. Geology and mineralogy of the Auki Crater, Tyrrhena Terra, Mars: A possible post impact-induced hydrothermal system. 281: 228-239</ref> <ref>Loizeau, D. et al. 2012. Characterization of hydrated silicate-bearing outcrops in tyrrhena Terra, Mars: implications to the alteration history of Mars. Icarus: 219, 476-497.</ref> <ref>Naumov, M. 2005. Principal features of impact-generated hydrothermal circulation systems: mineralogical and geochemical evidence. Geofluids: 5, 165-184.</ref> <ref>Ehlmann, B., et al. 2011. Evidence for low-grade metamorphism, hydrothermal alteration, and diagenesis on Mars from phyllosilicate mineral assemblages. Clays Clay Miner: 59, 359-377.</ref> <ref>Osinski, G. et al. 2013. Impact-generated hydrothermal systems on Earth and Mars. Icarus: 224, 347-363.</ref> <ref>Schwenzer, S., D. Kring. 2013. Alteration minerals in impact-generated hydrothermal systems – Exploring host rock variability. Icarus: 226, 487-496.</ref> Evidence of other hydrothermal systems around craters other than Auki has been found by different groups of scientists.<ref>Marzo, G., et al. 2010. Evidence for hesperian impact-induced hydrothermalism on Mars. Icarus: 667-683.</ref> <ref>Mangold, N., et al. 2012. Hydrothermal alteration in a late hesperian impact crater on Mars. 43rd Lunar and Planetary Science. #1209.</ref> <ref>Tornabene, L., et al. 2009. Parautochthonous megabreccias and possible evidence of impact-induced hydrothermal alteration in holden crater, Mars. 40th LPSC. #1766.</ref>

	<gallery class="center" widths="380px" heights="360px">		<gallery class="center" widths="380px" heights="360px">
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	==Channels==		==Channels==

	There is enormous evidence that water once flowed in river valleys and channels on Mars. Images of curved channels have been seen in images from Mars spacecraft dating back to the early ~~seventies~~ with the Mariner 9 orbiter.<ref>Baker, V. 1982. The Channels of Mars. Univ. of Tex. Press, Austin, TX</ref> <ref>Baker, V., R. Strom, R., V. Gulick, J. Kargel, G. Komatsu, V. Kale. 1991. Ancient oceans, ice sheets and the hydrological cycle on Mars. Nature 352, 589–594.</ref> <ref>Carr, M. 1979. Formation of Martian flood features by release of water from confined aquifers. J. Geophys. Res. 84, 2995–300.</ref> <ref>Komar, P. 1979. Comparisons of the hydraulics of water flows in Martian outflow channels with flows of similar scale on Earth. Icarus 37, 156–181.</ref>		There is enormous evidence that water once flowed in river valleys and channels on Mars. Images of curved channels have been seen in images from Mars spacecraft dating back to the early 70's with the Mariner 9 orbiter.<ref>Baker, V. 1982. The Channels of Mars. Univ. of Tex. Press, Austin, TX</ref> <ref>Baker, V., R. Strom, R., V. Gulick, J. Kargel, G. Komatsu, V. Kale. 1991. Ancient oceans, ice sheets and the hydrological cycle on Mars. Nature 352, 589–594.</ref> <ref>Carr, M. 1979. Formation of Martian flood features by release of water from confined aquifers. J. Geophys. Res. 84, 2995–300.</ref> <ref>Komar, P. 1979. Comparisons of the hydraulics of water flows in Martian outflow channels with flows of similar scale on Earth. Icarus 37, 156–181.</ref>
	Vallis (plural ''valles'') is the Latin word for 'valley. It is used in planetary geology for the naming of features on other planets, including what could be old river valleys that were discovered on Mars, when probes were first sent to Mars. The Viking Orbiters caused a revolution in our ideas about water on Mars; river valleys were found in many areas. ~~Space craft~~ cameras showed that floods of water broke through dams, carved deep valleys, eroded grooves into bedrock, and traveled thousands of kilometers.<ref>Kieffer\|title=Mars\|url=https://books.google.com/books?id=NoDvAAAAMAAJ\|accessdate=7 March 2011\|date=1992\|publisher=University of Arizona Press\|</ref> <ref>Raeburn, P. 1998. Uncovering the Secrets of the Red Planet Mars. National Geographic Society. Washington D.C.</ref> <ref>Moore, P. et al. 1990. The Atlas of the Solar System. Mitchell Beazley Publishers NY, NY.</ref>		Vallis (plural ''valles'') is the Latin word for 'valley. It is used in planetary geology for the naming of features on other planets, including what could be old river valleys that were discovered on Mars, when probes were first sent to Mars. The Viking Orbiters caused a revolution in our ideas about water on Mars; river valleys were found in many areas. Spacecraft cameras showed that floods of water broke through dams, carved deep valleys, eroded grooves into bedrock, and traveled thousands of kilometers.<ref>Kieffer\|title=Mars\|url=https://books.google.com/books?id=NoDvAAAAMAAJ\|accessdate=7 March 2011\|date=1992\|publisher=University of Arizona Press\|</ref> <ref>Raeburn, P. 1998. Uncovering the Secrets of the Red Planet Mars. National Geographic Society. Washington D.C.</ref> <ref>Moore, P. et al. 1990. The Atlas of the Solar System. Mitchell Beazley Publishers NY, NY.</ref>

	<gallery class="center" widths="380px" heights="360px">		<gallery class="center" widths="380px" heights="360px">
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	==Linear ridge networks==		==Linear ridge networks==

	Linear ridge networks are found in various places on Mars in and around craters.<ref>Head, J., J. Mustard. 2006. Breccia dikes and crater-related faults in impact craters on Mars: Erosion and exposure on the floor of a crater 75 km in diameter at the dichotomy boundary, Meteorit. Planet Science: 41, 1675-1690.</ref> Ridges often appear as mostly straight segments that intersect in a lattice-like manner. They are hundreds of meters long, tens of meters high, and several meters wide. Scientists are not totally sure what caused these ridges, but one popular idea is that impacts created fractures in the surface, these fractures later acted as channels for fluids. Fluids ~~cemented the structures~~. With the passage of time, surrounding material was eroded away, thereby leaving hard ridges behind.		Linear ridge networks are found in various places on Mars in and around craters.<ref>Head, J., J. Mustard. 2006. Breccia dikes and crater-related faults in impact craters on Mars: Erosion and exposure on the floor of a crater 75 km in diameter at the dichotomy boundary, Meteorit. Planet Science: 41, 1675-1690.</ref> Ridges often appear as mostly straight segments that intersect in a lattice-like manner. They are hundreds of meters long, tens of meters high, and several meters wide. Scientists are not totally sure what caused these ridges, but one popular idea is that impacts created fractures in the surface, these fractures later acted as channels for fluids. Fluids hardened. With the passage of time, surrounding material was eroded away, thereby leaving hard ridges behind.
	Since the ridges occur in locations with clay, these formations could serve as a marker for past water because clay requires water to be produced.<ref>Mangold et al. 2007. Mineralogy of the Nili Fossae region with OMEGA/Mars Express data: 2. Aqueous alteration of the crust. J. Geophys. Res., 112, doi:10.1029/2006JE002835.</ref> <ref>Mustard et al., 2007. Mineralogy of the Nili Fossae region with OMEGA/Mars Express data: 1. Ancient impact melt in the Isidis Basin and implications for the transition from the Noachian to Hesperian, J. Geophys. Res., 112.</ref> <ref>Mustard et al., 2009. Composition, Morphology, and Stratigraphy of Noachian Crust around the Isidis Basin, J. Geophys. Res., 114, doi:10.1029/2009JE003349.</ref> Water here could have supported past life in these locations. Clay ~~may also~~ preserve fossils or other traces of past life.		Since the ridges occur in locations with clay, these formations could serve as a marker for past water because clay requires water to be produced.<ref>Mangold et al. 2007. Mineralogy of the Nili Fossae region with OMEGA/Mars Express data: 2. Aqueous alteration of the crust. J. Geophys. Res., 112, doi:10.1029/2006JE002835.</ref> <ref>Mustard et al., 2007. Mineralogy of the Nili Fossae region with OMEGA/Mars Express data: 1. Ancient impact melt in the Isidis Basin and implications for the transition from the Noachian to Hesperian, J. Geophys. Res., 112.</ref> <ref>Mustard et al., 2009. Composition, Morphology, and Stratigraphy of Noachian Crust around the Isidis Basin, J. Geophys. Res., 114, doi:10.1029/2009JE003349.</ref> Water here could have supported past life in these locations. Clay near these structures could preserve fossils or other traces of past life.

	<gallery class="center" widths="380px" heights="360px">		<gallery class="center" widths="380px" heights="360px">


	ESP 045992 1780ridges.jpg\|Wide view of several groups of linear ridges~~, as seen by HiRISE under HiWish program~~		ESP 045992 1780ridges.jpg\|Wide view of several groups of linear ridges

	45992 1780ridgeswide.jpg\|Close view of ridges		45992 1780ridgeswide.jpg\|Close view of ridges
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	46269 1770ridgesindepression.jpg\|Close view of ridge networks Since some ridges are at the bottom of the depression, the ridges may be from a lower layer.		46269 1770ridgesindepression.jpg\|Close view of ridge networks Since some ridges are at the bottom of the depression, the ridges may be from a lower and therefore older layer.

	</gallery>		</gallery>
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	Close, color view of dunes Ripples are visible on dune surface.		Close, color view of dunes Ripples are visible on dune surface.

	Sand dunes have been found in many places on Mars. They are usually in low spots—like crater floors. In HiRISE images they can appear in a variety of pretty colors. The colors are somewhat artificial. NASA modifies colors to determine mineral composition. 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>http://hirise.lpl.arizona.edu/ESP_016459_1830</ref> <ref name>Michael H. Carr\|title=The surface of Mars\|url=https://books.google.com/books?id=uLHlJ6sjohwC\|accessdate=21 March 2011\|year=2006\|publisher=Cambridge University Press\|</ref> Black sand can be found on Earth on Hawaii and on some tropical South Pacific islands.<ref>https://www.desertusa.com/desert-activity/sand-dune-wind1.html</ref>		Sand dunes have been found in many places on Mars. They are usually in low spots—like crater floors. In HiRISE images they can appear in a variety of pretty colors. The colors are somewhat artificial. NASA modifies colors to determine mineral composition. The presence of dunes shows that the planet has an atmosphere with wind, for dunes require wind to pile up the sand. Although Mars has strong winds at times, we must remember that the Martian atmosphere is only about 1 % as dense as the Earth's. Hence, a wind speed of a 60-mph storm on Mars would feel more like 6 mph (9.6 km/hr).<ref> https://www.space.com/30663-the-martian-dust-storms-a-breeze.html</ref> Most dunes on Mars are black because of the weathering of the volcanic rock basalt.<ref>http://hirise.lpl.arizona.edu/ESP_016459_1830</ref> <ref name>Michael H. Carr\|title=The surface of Mars\|url=https://books.google.com/books?id=uLHlJ6sjohwC\|accessdate=21 March 2011\|year=2006\|publisher=Cambridge University Press\|</ref> Black sand can be found on Earth on Hawaii and on some tropical South Pacific islands.<ref>https://www.desertusa.com/desert-activity/sand-dune-wind1.html</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>https://www.youtube.com/watch?v=ur_TeOs3S64</ref> <ref>https://uanews.arizona.edu/story/the-flowing-sands-of-mars</ref> <ref>Cardinale, M., S. Silvestro, D. Vazd, T. Michaels, M. Bourke, G. Komatsu, L. Marinangeli. 2016. Present-day aeolian activity in Herschel Crater, Mars. Icarus: 265, 139-148.</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>https://www.youtube.com/watch?v=ur_TeOs3S64</ref> <ref>https://uanews.arizona.edu/story/the-flowing-sands-of-mars</ref> <ref>Cardinale, M., S. Silvestro, D. Vazd, T. Michaels, M. Bourke, G. Komatsu, L. Marinangeli. 2016. Present-day aeolian activity in Herschel Crater, Mars. Icarus: 265, 139-148.</ref>
	For a dune to move, 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 iimages are enlarged, some dunes on Mars display ripples on their surfaces.<ref>https://www.jpl.nasa.gov/news/news.php?feature=6551</ref>		For a dune to move, 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 iimages are enlarged, some dunes on Mars display ripples on their surfaces.<ref>https://www.jpl.nasa.gov/news/news.php?feature=6551</ref>