Difference between revisions of "Memnonia quadrangle"

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The Memnonia quadrangle contains some nice river valleys including a large ancient river system called Mangala Vallis.    There are also wind-eroded deposits and lava flows from the large volcanic region called Tharsis.
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The Memnonia quadrangle contains some nice ancient river valleys including a large river system called Mangala Vallis.    There are also wind-eroded deposits and lava flows from the large volcanic region called Tharsis.
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The Memnonia quadrangle is one of a series of 30 quadrangle maps of Mars used by the United States Geological Survey (USGS) and is also referred to as MC-16 (Mars Chart-16).<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 Memnonia quadrangle is one of a series of 30 quadrangle maps of Mars used by the United States Geological Survey (USGS) and is also referred to as MC-16 (Mars Chart-16).<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>
 
This quadrangle covers latitude 30°S  to 0° and longitude 135° to 180° W (225-180 E).<ref>[https://astrogeology.usgs.gov/Projects/MapBook/fulllisting.jsp?mapNumber=633 USGS Astrogeology: Planetary Map Listing</ref>   
 
This quadrangle covers latitude 30°S  to 0° and longitude 135° to 180° W (225-180 E).<ref>[https://astrogeology.usgs.gov/Projects/MapBook/fulllisting.jsp?mapNumber=633 USGS Astrogeology: Planetary Map Listing</ref>   
 
The name comes from a classic name that refers to the Land of Memnon, King of Ethiopia.  It was approved in 1958 by IAU.
 
The name comes from a classic name that refers to the Land of Memnon, King of Ethiopia.  It was approved in 1958 by IAU.
 
Memnonia includes parts of the following classical regions of Mars: Arcadia Planitia, Amazonis Planitia, Lucus Planum, Terra Sirenum, Daedalia Planum, and Terra Cimmeria.  Part of the Medusae Fossae Formation is found in the Memnonia quadrangle.  The western part of Memnonia is a highly cratered highland region that exhibits a large range of crater degradation.
 
Memnonia includes parts of the following classical regions of Mars: Arcadia Planitia, Amazonis Planitia, Lucus Planum, Terra Sirenum, Daedalia Planum, and Terra Cimmeria.  Part of the Medusae Fossae Formation is found in the Memnonia quadrangle.  The western part of Memnonia is a highly cratered highland region that exhibits a large range of crater degradation.
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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.
 
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.
  
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Vallis (plural ''valles'') is the Latin word for ''valley''. It is used in planetary geology for the naming of  features on other planets that resemble river valleys.  The Memnonia quadrangle contains many curved valleys that are probably old river valleys.
 
Vallis (plural ''valles'') is the Latin word for ''valley''. It is used in planetary geology for the naming of  features on other planets that resemble river valleys.  The Memnonia quadrangle contains many curved valleys that are probably old river valleys.
 
There is enormous evidence that water once flowed in river valleys 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 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>  
The Viking Orbiters caused a revolution in our ideas about water on Mars; huge 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>Hugh H. Kieffer (1992). Mars. University of Arizona Press. ISBN 978-0-8165-1257-7.</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>  Some valles on Mars (Mangala Vallis, Athabasca Vallis, Granicus Vallis, and Tinjar Valles) clearly begin at grabenGraben are long, mostly straight troughs.  They are caused by a stretching of the crust—on Mars this is a result of the weight of huge volcanoes.  On the other hand, some of the large outflow channels begin in rubble-filled low areas called chaos or chaotic terrain.  It has been suggested that massive amounts of water were trapped under pressure beneath a thick cryosphere (layer of frozen ground), then the water was suddenly released, perhaps when the cryosphere was broken by a fault.<ref>Carr, M.  1979.  Formation of martian flood features by release of water from confined aquifers.  J. Geophys. Res.  84:  2995-3007.</ref> <ref>Hanna, J. and R. Phillips.  2005.  Tectonic pressurization of aquifers in the formation of Mangala and Athabasca Valles on Mars.  LPSC XXXVI.  Abstract 2261.</ref>
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The Viking Orbiters caused a revolution in our ideas about water on Mars; they found huge river valleys 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>Hugh H. Kieffer (1992). Mars. University of Arizona Press. ISBN 978-0-8165-1257-7.</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>  Some valles on Mars (Mangala Vallis, Athabasca Vallis, Granicus Vallis, and Tinjar Valles) clearly begin at grabensGrabens are long, mostly straight troughs.  They are caused by a stretching of the crust—on Mars this is a result of the weight of huge volcanoes.  On the other hand, some of the large outflow channels begin in rubble-filled low areas called chaos or chaotic terrain.  It has been suggested that some chaotic terrain was formed when massive amounts of water were suddenly released after being trapped under a thick cryosphere (layer of frozen ground)--perhaps when the cryosphere was broken by a fault.<ref>Carr, M.  1979.  Formation of martian flood features by release of water from confined aquifers.  J. Geophys. Res.  84:  2995-3007.</ref> <ref>Hanna, J. and R. Phillips.  2005.  Tectonic pressurization of aquifers in the formation of Mangala and Athabasca Valles on Mars.  LPSC XXXVI.  Abstract 2261.</ref>
  
 
<gallery class="center"  widths="380px" heights="360px">
 
<gallery class="center"  widths="380px" heights="360px">
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ESP 045897 1645streamlined.jpg|Streamlined feature, as seen by HiRISE under HiWish program
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ESP 045897 1645streamlined.jpg|Streamlined feature Such shapes were made by vast floods of water.
  
 
</gallery>
 
</gallery>
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[[File: ESP 045779 1730meander.jpg|600pxr|Channel showing an old oxbow and a cutoff, as seen by HiRISE under HiWish program]]
 
[[File: ESP 045779 1730meander.jpg|600pxr|Channel showing an old oxbow and a cutoff, as seen by HiRISE under HiWish program]]
  
     Channel showing an old oxbow and a cutoff, as seen by HiRISE under HiWish program
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     Channel showing an old oxbow and a cutoff These are usually thought to be from water flowing over a long period of time.
  
 
[[File:ESP 047467 1685channalridge.jpg|600pxr|Channel that has eroded through a wrinkle ridge, as seen by HiRISE under HiWish program. Arrow shows point where channel eroded through ridge.]]
 
[[File:ESP 047467 1685channalridge.jpg|600pxr|Channel that has eroded through a wrinkle ridge, as seen by HiRISE under HiWish program. Arrow shows point where channel eroded through ridge.]]
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Besides river like forms, other evidence of past water in the region has been discovered in this region.  Layered sedimentary rocks were found in the wall and floor of Columbus Crater.  These rocks could have been deposited by water or by wind.  In addition hydrated minerals were found in some of the layers, and those types of minerals are formed in water environments.<ref>http://hirise.lpl.arizona.edu/PSP_010281_1510 |title=HiRISE &#124; Sedimentary Layers in Columbus Crater (PSP_010281_1510) |publisher=Hirise.lpl.arizona.edu |date= |</ref>
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Besides river like forms, other evidence of past water in the region has been discovered in this region.  Layered sedimentary rocks were found in the wall and floor of Columbus Crater.  These rocks could have been deposited by water or by wind.  But, there is evidence that it was  water since hydrated minerals were found in some of the layers, and those types of minerals are formed in water environments.<ref>http://hirise.lpl.arizona.edu/PSP_010281_1510 |title=HiRISE &#124; Sedimentary Layers in Columbus Crater (PSP_010281_1510) |publisher=Hirise.lpl.arizona.edu |date= |</ref>
  
 
==Mangala Vallis==
 
==Mangala Vallis==
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<gallery class="center"  widths="380px" heights="360px">
 
<gallery class="center"  widths="380px" heights="360px">
  
Image:Columbus Crater Layers.JPG|Columbus Crater Layers, as seen by [[HiRISE]].  This false-color image is about 800 feet across.  Some of the layers contain hydrated minerals such as clay and sulfates.
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Image:Columbus Crater Layers.JPG|Columbus Crater Layers, as seen by HiRISE.  This false-color image is about 800 feet across.  Some of the layers contain hydrated minerals such as clay and sulfates.
 
Image:Layers in Monument Valley.jpg|Layers in Monument Valley.  These are accepted as being formed, at least in part, by water deposition.  Since Mars contains similar layers, water remains as a major cause of layering on Mars.
 
Image:Layers in Monument Valley.jpg|Layers in Monument Valley.  These are accepted as being formed, at least in part, by water deposition.  Since Mars contains similar layers, water remains as a major cause of layering on Mars.
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ESP 035848 1510memnoniacraterlayers.jpg|Layers in crater wall, as seen by HiRISE under [[HiWish program]]
 
ESP 035848 1510memnoniacraterlayers.jpg|Layers in crater wall, as seen by HiRISE under [[HiWish program]]
ESP 039673 1705layeredbuttes.jpg|Layers exposed at the base of a group of buttes in Mangala Valles in Memnonia quadrangle Arrows point to boulders sitting in pits.  The pits may have formed by winds, heat from the boulders melting ground ice, or some other process.
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ESP 052030 1560crater.jpg|Crater displaying layers
 
ESP 052030 1560crater.jpg|Crater displaying layers
  
 
</gallery>
 
</gallery>
   
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[[File:ESP 039673 1705layeredbuttes.jpg|600pxr|Layers exposed at the base of a group of buttes in Mangala Valles in Memnonia quadrangle Arrows point to boulders sitting in pits. The pits may have formed by winds, heat from the boulders melting ground ice, or some other process.]]
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Layers exposed at the base of a group of buttes in Mangala Valles in Memnonia quadrangle Arrows point to boulders sitting in pits.  The pits may have formed by winds, heat from the boulders melting ground ice, or some other process.
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==Craters==
 
==Craters==
  
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Impact craters generally have a rim with ejecta around them, in contrast volcanic craters usually do not have a rim or ejecta deposits.  As craters get larger (greater than 10 km in diameter) they usually have a central peak.<ref>http://www.lpi.usra.edu/publications/slidesets/stones/ |title=Stones, Wind, and Ice: A Guide to Martian Impact Craters |publisher=Lpi.usra.edu |date= |</ref> The peak is caused by a rebound of the crater floor following the impact.<ref>Hugh H. Kieffer|title=Mars|url=https://books.google.com/books|date=1992|publisher=University of Arizona Press|</ref>  Sometimes craters will display layers; those layers show us what kinds of rocks were present in the past.  Since the collision that produces a crater is like a powerful explosion, rocks from deep underground are tossed unto the surface.  Hence, rocks around the crater are samples of  what lies deep under the surface.  At times, bright rays surround craters because the impact has gone down to a bright layer of rocks, and then tossed out the bright rocks on the darker surface.  An image below from Mars Global Surveyor shows this.
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Impact craters generally have a rim with ejecta around them, in contrast volcanic craters usually do not have a rim or ejecta deposits.  As craters get larger (greater than 10 km in diameter) they usually have a central peak.<ref>http://www.lpi.usra.edu/publications/slidesets/stones/ |title=Stones, Wind, and Ice: A Guide to Martian Impact Craters |publisher=Lpi.usra.edu |date= |</ref> The peak is caused by a rebound of the crater floor following the impact.<ref>Hugh H. Kieffer|title=Mars|url=https://books.google.com/books|date=1992|publisher=University of Arizona Press|</ref>  Sometimes craters will display layers; those layers show us what kinds of rocks were present in the past.  Since the collision that produces a crater is like a powerful explosion, rocks from deep underground are tossed unto the surface.  Hence, rocks around the crater are samples of  what lies deep under the surface.  At times, bright rays surround craters because the impact has gone down to a bright layer of rocks, and then placed bright rocks on the darker surface.  An image above from Mars Global Surveyor shows this.
  
 
<gallery class="center"  widths="380px" heights="360px">
 
<gallery class="center"  widths="380px" heights="360px">
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ESP 035163 1560memnoniafractures.jpg|Troughs on the floor of Bernard Crater showing many boulders
 
ESP 035163 1560memnoniafractures.jpg|Troughs on the floor of Bernard Crater showing many boulders
  
ESP 034596 1565memnoniafractures.jpg|Troughs on the floor of Bernard Crater
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ESP 034596 1565memnoniafractures.jpg|More examples of troughs on the floor of Bernard Crater
  
  
Image:27001layersclose.jpg|Close-up of layers in a pit on crater floor, as seen by HiRISE under HiWish program.
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Image:27001layersclose.jpg|Close-up of layers in a pit on crater floor The box shows the size of a football field.
  
 
Wikiburton.jpg|Middle section of Burton Crater, showing central mound, as seen by CTX camera (on Mars Reconnaissance Orbiter).
 
Wikiburton.jpg|Middle section of Burton Crater, showing central mound, as seen by CTX camera (on Mars Reconnaissance Orbiter).
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==Ridges==
 
==Ridges==
  
Ridges on Mars may be due to different causes.  Long straight ridges are thought to be dikes.  Curved and branched ridges may be examples of inverted topography, and groups of straight ridges that cross each other may be the result of impacts.  These intersecting box-like ridges are called linear ridge networks.
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Ridges on Mars may be due to different causes.  Long straight ridges are thought to be dikes (from magma movements).  Curved and branched ridges may be examples of inverted topography, and groups of straight ridges that cross each other may be the result of impacts.  These intersecting box-like ridges are called 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.  Even though the exact origin is not known at present, one popular idea is that impacts created fractures in the surface, these fractures later acted as channels for fluids.  Fluids carried minerals which hardened into the ridges we see today.  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.  Even though the exact origin is not known at present, one popular idea is that impacts created fractures in the surface, these fractures later acted as channels for fluids.  Fluids carried minerals which hardened into the ridges we see today.  With the passage of time, surrounding material was eroded away, thereby leaving hard ridges behind.
  
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44777 1725yardangs2.jpg|Close view of yardangs in previous image
 
44777 1725yardangs2.jpg|Close view of yardangs in previous image
 
44777 1725yardangsclose.jpg|Close view of yardangs from a previous image, as seen by HiRISE under HiWish program
 
44777 1725yardangsclose.jpg|Close view of yardangs from a previous image, as seen by HiRISE under HiWish program
Image:27001yardangs.jpg|Close up of crater floor showing yardangs and dark slope streaks, as seen by HiRISE under HiWish program
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Image:27001yardangs.jpg|Close up of crater floor showing yardangs and dark slope streaks
  
 
45831 1750yardangs.jpg|Yardangs
 
45831 1750yardangs.jpg|Yardangs
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== Dark slope streaks ==
 
== Dark slope streaks ==
  
Many places on Mars show dark slope streaks on steep slopes, like crater walls.  The youngest streaks are the darkest<ref>Schorghofer, N, et al.  2007.  Three decades of slope streak activity on Mars.  Icarus.  191:132-140.</ref>  Often they begin as a small narrow spot then widen and extend downhill for hundreds of meters.  It is most generally accepted that the streaks represent avalanches of dust.<ref>Ferris, J. C.; Dohm, J.M.; Baker, V.R.; Maddock III, T. (2002). Dark Slope Streaks on Mars: Are Aqueous Processes Involved? ''Geophys. Res. Lett.,'' '''29'''(10), 1490, </ref>    When a thin layer of dust is removed, the underlying surface is dark.  Much of the Martian surface is covered with dust.  Dust storms are frequent, especially when the spring season begins in the southern hemisphere.  At that time, Mars is 40% closer to the sun.  The orbit of Mars is much more elliptical then the Earth's.  That is the difference between the farthest point from the sun and the closest point to the sun is very great for Mars, but very little for the Earth.  Also, every few years, the entire planet is engulfed in a global dust storm.  When NASA's [[Mariner 9]] craft arrived there, nothing could be seen through the dust storm.<ref>Kieffer.  1992.  ISBN|0-517-00192-6</ref> Other global dust storms have also been observed, since that time.  Dark streaks can be seen in the image below taken with HiRISE of the central mound in Nicholson Crater.  At least one streak in the image splits into two when encountering an obstacle.
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Many places on Mars show dark slope streaks on steep slopes, like crater walls.  The youngest streaks are the darkest<ref>Schorghofer, N, et al.  2007.  Three decades of slope streak activity on Mars.  Icarus.  191:132-140.</ref>  Often they begin as a small narrow spot then widen and extend downhill for hundreds of meters.  It is most generally accepted that the streaks represent avalanches of dust.<ref>Ferris, J. C.; Dohm, J.M.; Baker, V.R.; Maddock III, T. (2002). Dark Slope Streaks on Mars: Are Aqueous Processes Involved? ''Geophys. Res. Lett.,'' '''29'''(10), 1490, </ref>    When a thin layer of dust is removed, the dark underlying surface becomes visible.  Much of the Martian surface is covered with dust with much of it resulting from dust storms.  Dust storms are frequent, especially when the spring season begins in the southern hemisphere.  At that time, Mars is 40% closer to the sun.  The orbit of Mars is much more elliptical then the Earth's.  That is the difference between the farthest point from the sun and the closest point to the sun is very great for Mars, but very little for the Earth.  Also, every few years, the entire planet is engulfed in a global dust storm.  When NASA's [[Mariner 9]] craft arrived there, nothing could be seen through the dust storm.<ref>Kieffer.  1992.  ISBN|0-517-00192-6</ref> Other global dust storms have also been observed, since that time.  Dark streaks can be seen in the image below taken with HiRISE of the central mound in Nicholson Crater.  At least one streak in the image splits into two when encountering an obstacle.
  
Research, published in January 2012 in Icarus, found that dark streaks were initiated by airblasts from meteorites traveling at supersonic speeds. After counting some 65,000 dark streaks around the impact site of a group of 5 new craters, the team of scientists  discovered patterns in the data.  The number of streaks was greatest closer to the impact site.  So, the impact somehow probably caused the streaks. Also, the distribution of the streaks formed a pattern with two wings extending from the impact site.  The curved wings resembled curved knives, called scimitars.  This pattern suggests that an interaction of airblasts from the group of meteorites shook dust loose enough to start dust avalanches that formed the many dark streaks.  At first it was thought that the shaking of the ground from the impact caused the dust avalanches, but if that was the case the dark streaks would have been arranged symmetrically around the impacts, rather than being concentrated into curved shapes.<ref>Kaylan J. Burleigh, Henry J. Melosh, Livio L. Tornabene, Boris Ivanov, Alfred S. McEwen, Ingrid J. Daubar. Impact air blast triggers dust avalanches on Mars. Icarus, 2012; 217 (1): 194 {{doi|10.1016/j.icarus.2011.10.026}}</ref> <ref>http://redplanet.asu.edu/ |title=Red Planet Report &#124; What's up with Mars |publisher=Redplanet.asu.edu |date= |</ref>
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Research, published in January 2012 in Icarus, found that dark streaks were initiated by airblasts from meteorites traveling at supersonic speeds. After counting some 65,000 dark streaks around the impact site of a group of 5 new craters, the team of scientists  discovered patterns in the data.  The number of streaks was greatest closer to the impact site.  So, the impact somehow probably caused the streaks. Also, the distribution of the streaks formed a pattern with two wings extending from the impact site.  The curved wings resembled curved knives, called scimitars.  This pattern suggests that an interaction of airblasts from the group of meteorites shook dust loose enough to start dust avalanches that formed the many dark streaks.  At first it was thought that the shaking of the ground from the impact caused the dust avalanches, but if that was the case the dark streaks would have been arranged symmetrically around the impacts, rather than being concentrated into curved shapes.<ref>Kaylan J. Burleigh, Henry J. Melosh, Livio L. Tornabene, Boris Ivanov, Alfred S. McEwen, Ingrid J. Daubar. Impact air blast triggers dust avalanches on Mars. Icarus, 2012; 217 (1): 194 10.1016/j.icarus.2011.10.026</ref> <ref>http://redplanet.asu.edu/ |title=Red Planet Report &#124; What's up with Mars |publisher=Redplanet.asu.edu |date= |</ref>
  
 
<gallery class="center"  widths="380px" heights="360px">
 
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==Fossa on Mars==
 
==Fossa on Mars==
  
Large troughs (long narrow depressions) are called fossae in the geographical language used for Mars.  This term is derived from Latin; therefore fossa is singular and fossae is plural.<ref>http://www.marsartgallery.com/marsnames.html |title=Mars Art Gallery Martian Feature Name Nomenclature |publisher=Marsartgallery.com |date= |</ref> Troughs form when the crust is stretched until it breaks.  The stretching can be due to the large weight of a nearby volcano.  A trough often has two breaks with a middle section lower, leaving steep cliffs along the sides; such a trough is called a graben.<ref>http://hirise.lpl.arizona.edu/PSP_008641_2105 |title=HiRISE &#124; Craters and Pit Crater Chains in Chryse Planitia (PSP_008641_2105) |publisher=Hirise.lpl.arizona.edu |date= |</ref> Lake George, in northern New York State, is a lake that sits in a graben.
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Large troughs (long narrow depressions) are called fossae in the geographical language used for Mars.  This term is derived from Latin; therefore fossa is singular and fossae is plural.<ref>http://www.marsartgallery.com/marsnames.html |title=Mars Art Gallery Martian Feature Name Nomenclature |publisher=Marsartgallery.com |date= |</ref> Troughs form when the crust is stretched until it breaks.  The stretching can be due to the great weight of a nearby volcano.  A trough often has two breaks with a middle section lower, leaving steep cliffs along the sides; such a trough is called a graben.<ref>http://hirise.lpl.arizona.edu/PSP_008641_2105 |title=HiRISE &#124; Craters and Pit Crater Chains in Chryse Planitia (PSP_008641_2105) |publisher=Hirise.lpl.arizona.edu |date= |</ref> Lake George, in northern New York State, is a lake that occupies a graben.
 
Other ideas have been suggested for the formation of fossae.  There is evidence that they are associated with dikes of magma.  Magma might move along, under the surface, breaking the rock and more importantly melting ice.  The resulting action would cause a crack to form at the surface.  Dikes caused both by tectonic stretching (extension) and by dikes are found in Iceland.<ref>http://hirise.lpl.arizona.edu/PSP_005376_1575 |title=HiRISE &#124; Graben in Memnonia Fossae (PSP_005376_1575) |publisher=Hirise.lpl.arizona.edu |date= |</ref>  An example of a graben caused by a dike is shown below in the image Memnonia Fossae, as seen by HiRISE.
 
Other ideas have been suggested for the formation of fossae.  There is evidence that they are associated with dikes of magma.  Magma might move along, under the surface, breaking the rock and more importantly melting ice.  The resulting action would cause a crack to form at the surface.  Dikes caused both by tectonic stretching (extension) and by dikes are found in Iceland.<ref>http://hirise.lpl.arizona.edu/PSP_005376_1575 |title=HiRISE &#124; Graben in Memnonia Fossae (PSP_005376_1575) |publisher=Hirise.lpl.arizona.edu |date= |</ref>  An example of a graben caused by a dike is shown below in the image Memnonia Fossae, as seen by HiRISE.
  
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Image:Graben in Memnonia Fossae.JPG|Graben in Memnonia Fossae, as seen by HiRISE.  This graben is believed to be the result of magmatic dikes rather than regional tectonic stretching.  The scale bar is 1000 meters long.
 
Image:Graben in Memnonia Fossae.JPG|Graben in Memnonia Fossae, as seen by HiRISE.  This graben is believed to be the result of magmatic dikes rather than regional tectonic stretching.  The scale bar is 1000 meters long.
  
Image:26987fossaepits.jpg|Large pits in Sirenum Fossae, as seen by HiRISE under HiWish program
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Image:26987fossaepits.jpg|Large pits in Sirenum Fossae Pits sometimes signal the start of a graben.
  
 
ESP 049854 1535troughcrater.jpg|Trough cutting through an impact crater,  
 
ESP 049854 1535troughcrater.jpg|Trough cutting through an impact crater,  
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[[File:52438cameramaparrow.jpg|600pxr|Map showing area covered in the above photos with a black rectangle. Blue arrow indicates the spot eventually imaged by HiRISE. The relative positions of Columbus Crater, Williams Crater, Ejriksson Crater, Dejnev Crater, and Bernard Crater are shown.]]
 
[[File:52438cameramaparrow.jpg|600pxr|Map showing area covered in the above photos with a black rectangle. Blue arrow indicates the spot eventually imaged by HiRISE. The relative positions of Columbus Crater, Williams Crater, Ejriksson Crater, Dejnev Crater, and Bernard Crater are shown.]]
  
Map showing area covered in the above photos with a black rectangle. Blue arrow indicates the spot eventually imaged by HiRISE. The relative positions of Columbus Crater, Williams Crater, Ejriksson Crater, Dejnev Crater, and Bernard Crater are shown.
+
Area in black rectangle is covered in the photos below. Blue arrow indicates the spot eventually imaged by HiRISE. The relative positions of Columbus Crater, Williams Crater, Ejriksson Crater, Dejnev Crater, and Bernard Crater are shown.
  
  
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Composite demonstrating relative resolution of 7 different cameras that imaged Mars: HiRISE (Mars Reconnaissance Orbiter), THEMIS VIS (Mars Odyssey), MOC-WAC (Mars Global Surveyor), HRSC (Mars Express), CTX (Mars Reconnaissance Orbiter),  Viking, Mariner 4.  Location is Memnonia quadrangle. Blue arrow on some pictures points to same location with different cameras. Red box with CTX image shows location of the next frame from HiRISE.
 
Composite demonstrating relative resolution of 7 different cameras that imaged Mars: HiRISE (Mars Reconnaissance Orbiter), THEMIS VIS (Mars Odyssey), MOC-WAC (Mars Global Surveyor), HRSC (Mars Express), CTX (Mars Reconnaissance Orbiter),  Viking, Mariner 4.  Location is Memnonia quadrangle. Blue arrow on some pictures points to same location with different cameras. Red box with CTX image shows location of the next frame from HiRISE.
  
 
</gallery>
 
  
 
==More features of Memnonia quadrangle==
 
==More features of Memnonia quadrangle==

Latest revision as of 13:14, 25 March 2020

Mars topography (MOLA dataset) HiRes (1).jpg
MC-16 Memnonia 0–30° S 135–180° W Quadrangles Atlas


The Memnonia quadrangle contains some nice ancient river valleys including a large river system called Mangala Vallis. There are also wind-eroded deposits and lava flows from the large volcanic region called Tharsis.

The Memnonia quadrangle is one of a series of 30 quadrangle maps of Mars used by the United States Geological Survey (USGS) and is also referred to as MC-16 (Mars Chart-16).[1] This quadrangle covers latitude 30°S to 0° and longitude 135° to 180° W (225-180 E).[2] The name comes from a classic name that refers to the Land of Memnon, King of Ethiopia. It was approved in 1958 by IAU. Memnonia includes parts of the following classical regions of Mars: Arcadia Planitia, Amazonis Planitia, Lucus Planum, Terra Sirenum, Daedalia Planum, and Terra Cimmeria. Part of the Medusae Fossae Formation is found in the Memnonia quadrangle. The western part of Memnonia is a highly cratered highland region that exhibits a large range of crater degradation.

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.

Valles

Vallis (plural valles) is the Latin word for valley. It is used in planetary geology for the naming of features on other planets that resemble river valleys. The Memnonia quadrangle contains many curved valleys that are probably old river valleys. There is enormous evidence that water once flowed in river valleys 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.[3] [4] [5] [6] The Viking Orbiters caused a revolution in our ideas about water on Mars; they found huge river valleys 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.[7] [8] [9] Some valles on Mars (Mangala Vallis, Athabasca Vallis, Granicus Vallis, and Tinjar Valles) clearly begin at grabens. Grabens are long, mostly straight troughs. They are caused by a stretching of the crust—on Mars this is a result of the weight of huge volcanoes. On the other hand, some of the large outflow channels begin in rubble-filled low areas called chaos or chaotic terrain. It has been suggested that some chaotic terrain was formed when massive amounts of water were suddenly released after being trapped under a thick cryosphere (layer of frozen ground)--perhaps when the cryosphere was broken by a fault.[10] [11]

Channel showing an old oxbow and a cutoff, as seen by HiRISE under HiWish program

   Channel showing an old oxbow and a cutoff  These are usually thought to be from water flowing over a long period of time.

Channel that has eroded through a wrinkle ridge, as seen by HiRISE under HiWish program. Arrow shows point where channel eroded through ridge.

               Channel that has eroded through a wrinkle ridge  Arrow shows point where channel eroded through ridge.


Besides river like forms, other evidence of past water in the region has been discovered in this region. Layered sedimentary rocks were found in the wall and floor of Columbus Crater. These rocks could have been deposited by water or by wind. But, there is evidence that it was water since hydrated minerals were found in some of the layers, and those types of minerals are formed in water environments.[12]

Mangala Vallis

Mangala Vallis is a major channel system that contains several basins which filled with water, and then the overflow went through a series of spillways.[13][14] One source of waters for the system was Memonia Fossae, but water also probably came from a large basin centered at 40 degrees S.[15][16] [17]

Layers

Many places on Mars show rocks arranged in layers. Layers are also called strata. Rock can form layers in a variety of ways. Volcanoes, wind, or water can produce layers.[18] Sometimes the layers are of different colors. Light-toned rocks on Mars have been associated with hydrated minerals like sulfates. The Mars Rover Opportunity examined such layers close-up with several instruments. Instruments on orbiting spacecraft have detected clay (also called phyllosilicate) in some layers. Recent research with an orbiting near-infrared spectrometer (which reveals the types of minerals present based on the wavelengths of light they absorb) found evidence of layers of both clay and sulfates in Columbus crater.[19] This is exactly what would appear if a large lake had slowly evaporated.[20] Moreover, because some layers contained gypsum, a sulfate which forms in relatively fresh water, life could have formed in the crater.[21] Scientists are excited about finding hydrated minerals such as sulfates and clays on Mars because they are usually formed in the presence of water.[22] Places that contain clays and/or other hydrated minerals would be good places to look for evidence of life.[23]


Layers exposed at the base of a group of buttes in Mangala Valles in Memnonia quadrangle Arrows point to boulders sitting in pits. The pits may have formed by winds, heat from the boulders melting ground ice, or some other process. Layers exposed at the base of a group of buttes in Mangala Valles in Memnonia quadrangle Arrows point to boulders sitting in pits. The pits may have formed by winds, heat from the boulders melting ground ice, or some other process.

Craters

Bright rays caused by impact throwing out a bright lower layer. Some bright layers contain hydrated minerals. Picture taken with Mars Global Surveyor, under the MOC Public Targeting Program.


Bright rays caused by impact throwing out a bright lower layer. Some bright layers contain hydrated minerals. Picture taken with Mars Global Surveyor, under the MOC Public Targeting Program.


Impact craters generally have a rim with ejecta around them, in contrast volcanic craters usually do not have a rim or ejecta deposits. As craters get larger (greater than 10 km in diameter) they usually have a central peak.[24] The peak is caused by a rebound of the crater floor following the impact.[25] Sometimes craters will display layers; those layers show us what kinds of rocks were present in the past. Since the collision that produces a crater is like a powerful explosion, rocks from deep underground are tossed unto the surface. Hence, rocks around the crater are samples of what lies deep under the surface. At times, bright rays surround craters because the impact has gone down to a bright layer of rocks, and then placed bright rocks on the darker surface. An image above from Mars Global Surveyor shows this.

Ridges

Ridges on Mars may be due to different causes. Long straight ridges are thought to be dikes (from magma movements). Curved and branched ridges may be examples of inverted topography, and groups of straight ridges that cross each other may be the result of impacts. These intersecting box-like ridges are called linear ridge networks. Linear ridge networks are found in various places on Mars in and around craters.[26] 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. Even though the exact origin is not known at present, one popular idea is that impacts created fractures in the surface, these fractures later acted as channels for fluids. Fluids carried minerals which hardened into the ridges we see today. With the passage of time, surrounding material was eroded away, thereby leaving hard ridges behind.

Yardangs

Yardangs are common in some regions on Mars, especially in what's called the "Medusae Fossae Formation."[27] They are formed by the action of wind on sand sized particles; hence they often point in the direction that the winds were blowing when they were formed.

Dark slope streaks

Many places on Mars show dark slope streaks on steep slopes, like crater walls. The youngest streaks are the darkest[28] Often they begin as a small narrow spot then widen and extend downhill for hundreds of meters. It is most generally accepted that the streaks represent avalanches of dust.[29] When a thin layer of dust is removed, the dark underlying surface becomes visible. Much of the Martian surface is covered with dust with much of it resulting from dust storms. Dust storms are frequent, especially when the spring season begins in the southern hemisphere. At that time, Mars is 40% closer to the sun. The orbit of Mars is much more elliptical then the Earth's. That is the difference between the farthest point from the sun and the closest point to the sun is very great for Mars, but very little for the Earth. Also, every few years, the entire planet is engulfed in a global dust storm. When NASA's Mariner 9 craft arrived there, nothing could be seen through the dust storm.[30] Other global dust storms have also been observed, since that time. Dark streaks can be seen in the image below taken with HiRISE of the central mound in Nicholson Crater. At least one streak in the image splits into two when encountering an obstacle.

Research, published in January 2012 in Icarus, found that dark streaks were initiated by airblasts from meteorites traveling at supersonic speeds. After counting some 65,000 dark streaks around the impact site of a group of 5 new craters, the team of scientists discovered patterns in the data. The number of streaks was greatest closer to the impact site. So, the impact somehow probably caused the streaks. Also, the distribution of the streaks formed a pattern with two wings extending from the impact site. The curved wings resembled curved knives, called scimitars. This pattern suggests that an interaction of airblasts from the group of meteorites shook dust loose enough to start dust avalanches that formed the many dark streaks. At first it was thought that the shaking of the ground from the impact caused the dust avalanches, but if that was the case the dark streaks would have been arranged symmetrically around the impacts, rather than being concentrated into curved shapes.[31] [32]

Fossa on Mars

Large troughs (long narrow depressions) are called fossae in the geographical language used for Mars. This term is derived from Latin; therefore fossa is singular and fossae is plural.[33] Troughs form when the crust is stretched until it breaks. The stretching can be due to the great weight of a nearby volcano. A trough often has two breaks with a middle section lower, leaving steep cliffs along the sides; such a trough is called a graben.[34] Lake George, in northern New York State, is a lake that occupies a graben. Other ideas have been suggested for the formation of fossae. There is evidence that they are associated with dikes of magma. Magma might move along, under the surface, breaking the rock and more importantly melting ice. The resulting action would cause a crack to form at the surface. Dikes caused both by tectonic stretching (extension) and by dikes are found in Iceland.[35] An example of a graben caused by a dike is shown below in the image Memnonia Fossae, as seen by HiRISE.

It appears that the water started coming out of the surface to form Mangala Vallis when a graben formed.[36]

Lava flows

Lava is common on Mars, as it is on many other planetary bodies.


Lava flow. Lava flow stopped when it encountered the higher ground of a mound. Picture was taken with HiRISE under HiWish program.

                                      Lava flow.  Lava flow stopped when it encountered the higher ground of a mound.

Fifty Years of Mars Imaging: from Mariner 4 to HiRISE

On October 3, 2017, HiRISE acquired a picture of Mars in the Memnonia quadrangle of a spot that has been imaged by 7 different cameras on different spacecraft over the past 50 years.[37] The pictures from the Red Planet started with one of the pictures from Mariner 4 in the summer of 1965. The following pictures show these pictures with their increasing resolution over the years. The resolution in the first image by Mariner 4 was 1.25 Km/pixel; that compares to the approximate 50 cm/pixel resolution of HiRISE.

Map showing area covered in the above photos with a black rectangle. Blue arrow indicates the spot eventually imaged by HiRISE. The relative positions of Columbus Crater, Williams Crater, Ejriksson Crater, Dejnev Crater, and Bernard Crater are shown.

Area in black rectangle is covered in the photos below. Blue arrow indicates the spot eventually imaged by HiRISE. The relative positions of Columbus Crater, Williams Crater, Ejriksson Crater, Dejnev Crater, and Bernard Crater are shown.


Composite demonstrating relative resolution of 7 different cameras that imaged Mars:HiRISE (Mars Reconnaissance Orbiter), THEMIS VIS (Mars Odyssey), MOC-WAC (Mars Global Surveyor), HRSC (Mars Express), CTX (Mars Reconnaissance Orbiter), Viking, Mariner 4. Location is Memnonia quadrangle.

Composite demonstrating relative resolution of 7 different cameras that imaged Mars:HiRISE (Mars Reconnaissance Orbiter), THEMIS VIS (Mars Odyssey), MOC-WAC (Mars Global Surveyor), HRSC (Mars Express), CTX (Mars Reconnaissance Orbiter), Viking, Mariner 4. Location is Memnonia quadrangle.


Composite demonstrating relative resolution of 7 different cameras that imaged Mars: HiRISE (Mars Reconnaissance Orbiter), THEMIS VIS (Mars Odyssey), MOC-WAC (Mars Global Surveyor), HRSC (Mars Express), CTX (Mars Reconnaissance Orbiter), Viking, Mariner 4. Location is Memnonia quadrangle. Blue arrow on some pictures points to same location with different cameras. Red box with CTX image shows location of the next frame from HiRISE.

Composite demonstrating relative resolution of 7 different cameras that imaged Mars: HiRISE (Mars Reconnaissance Orbiter), THEMIS VIS (Mars Odyssey), MOC-WAC (Mars Global Surveyor), HRSC (Mars Express), CTX (Mars Reconnaissance Orbiter), Viking, Mariner 4. Location is Memnonia quadrangle. Blue arrow on some pictures points to same location with different cameras. Red box with CTX image shows location of the next frame from HiRISE.


More features of Memnonia quadrangle

See also


External links

References

  1. 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.
  2. [https://astrogeology.usgs.gov/Projects/MapBook/fulllisting.jsp?mapNumber=633 USGS Astrogeology: Planetary Map Listing
  3. Baker, V. 1982. The Channels of Mars. Univ. of Tex. Press, Austin, TX
  4. 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.
  5. Carr, M. 1979. Formation of Martian flood features by release of water from confined aquifers. J. Geophys. Res. 84, 2995–300.
  6. 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.
  7. Hugh H. Kieffer (1992). Mars. University of Arizona Press. ISBN 978-0-8165-1257-7.
  8. Raeburn, P. 1998. Uncovering the Secrets of the Red Planet Mars. National Geographic Society. Washington D.C.
  9. Moore, P. et al. 1990. The Atlas of the Solar System. Mitchell Beazley Publishers NY, NY.
  10. Carr, M. 1979. Formation of martian flood features by release of water from confined aquifers. J. Geophys. Res. 84: 2995-3007.
  11. Hanna, J. and R. Phillips. 2005. Tectonic pressurization of aquifers in the formation of Mangala and Athabasca Valles on Mars. LPSC XXXVI. Abstract 2261.
  12. http://hirise.lpl.arizona.edu/PSP_010281_1510 |title=HiRISE | Sedimentary Layers in Columbus Crater (PSP_010281_1510) |publisher=Hirise.lpl.arizona.edu |date= |
  13. Cabrol, N. and E. Grin (eds.). 2010. Lakes on Mars. Elsevier. NY.
  14. Emrick, C. and R. De Hon. 1999. Flood discharge through Labou Vallis, Mars. Lunar Planet. Sci. Conf. XXX: Abstract #1893.
  15. Zimbelman, J. et al. 1992. Volatile history of Mangala Valles, Mars. J. Geophys. Res. 97: 18309-18317
  16. De Hon, R. 1994. Lacustrine sedimentation in lower Mangals Valles. Mars Lunar Planet. Sci. Conf. XXVII: 295-296
  17. http://www.msss.com/http/ps/channels/channels.html |title=Mars Channels and Valleys |publisher=Msss.com |
  18. http://hirise.lpl.arizona.edu?PSP_008437_1750 |title=HiRISE | High Resolution Imaging Science Experiment |publisher=Hirise.lpl.arizona.edu?psp_008437_1750 |
  19. Cabrol, N. and E. Grin (eds.). 2010. Lakes on Mars. Elsevier.NY.
  20. Wray, J. et al. 2009. Columbus Crater and other possible plaelakes in Terra Sirenum, Mars. Lunar and Planetary Science Conference. 40: 1896.
  21. http://news.nationalgeographic.com/news/2009/11/091125-mars-crater-lake-michigan-water_2.html |title=Martian "Lake Michigan" Filled Crater, Minerals Hint |publisher=News.nationalgeographic.com |
  22. http://themis.asu.edu/features/nilosyrtis |title=Target Zone: Nilosyrtis? | Mars Odyssey Mission THEMIS |publisher=Themis.asu.edu |
  23. http://hirise.lpl.arizona.edu/PSP_004046_2080 |title=HiRISE | Craters and Valleys in the Elysium Fossae (PSP_004046_2080) |publisher=Hirise.lpl.arizona.edu |date= |
  24. http://www.lpi.usra.edu/publications/slidesets/stones/ |title=Stones, Wind, and Ice: A Guide to Martian Impact Craters |publisher=Lpi.usra.edu |date= |
  25. Hugh H. Kieffer|title=Mars|url=https://books.google.com/books%7Cdate=1992%7Cpublisher=University of Arizona Press|
  26. 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.
  27. http://adsabs.harvard.edu/abs/1979JGR....84.8147W SAO/NASA ADS Astronomy Abstract Service: Yardangs on Mars
  28. Schorghofer, N, et al. 2007. Three decades of slope streak activity on Mars. Icarus. 191:132-140.
  29. Ferris, J. C.; Dohm, J.M.; Baker, V.R.; Maddock III, T. (2002). Dark Slope Streaks on Mars: Are Aqueous Processes Involved? Geophys. Res. Lett., 29(10), 1490,
  30. Kieffer. 1992. ISBN|0-517-00192-6
  31. Kaylan J. Burleigh, Henry J. Melosh, Livio L. Tornabene, Boris Ivanov, Alfred S. McEwen, Ingrid J. Daubar. Impact air blast triggers dust avalanches on Mars. Icarus, 2012; 217 (1): 194 10.1016/j.icarus.2011.10.026
  32. http://redplanet.asu.edu/ |title=Red Planet Report | What's up with Mars |publisher=Redplanet.asu.edu |date= |
  33. http://www.marsartgallery.com/marsnames.html |title=Mars Art Gallery Martian Feature Name Nomenclature |publisher=Marsartgallery.com |date= |
  34. http://hirise.lpl.arizona.edu/PSP_008641_2105 |title=HiRISE | Craters and Pit Crater Chains in Chryse Planitia (PSP_008641_2105) |publisher=Hirise.lpl.arizona.edu |date= |
  35. http://hirise.lpl.arizona.edu/PSP_005376_1575 |title=HiRISE | Graben in Memnonia Fossae (PSP_005376_1575) |publisher=Hirise.lpl.arizona.edu |date= |
  36. Michael H. Carr|title=The surface of Mars|url=https://books.google.com/books?id=uLHlJ6sjohwC%7Caccessdate=21 March 2011|date=2006|publisher=Cambridge University Press|isbn=978-0-521-87201-0
  37. https://hirise.lpl.arizona.edu/ESP_052438_1560