Difference between revisions of "Ismenius Lacus quadrangle"

From Marspedia
Jump to: navigation, search
Line 172: Line 172:
  
  
Glaciers formed much of the observable surface in large areas of Mars.  Much of the area in high latitudes, especially the Ismenius Lacus quadrangle, is believed to still contain enormous amounts of water ice.<ref"Kieffer1992"/><ref"Plaut, J. 2008"/> <ref>http://www.esa.int/SPECIALS/Mars_Express/SEMBS5V681F_0.html</ref>  In March 2010, scientists released the results of a radar study of an area called Deuteronilus Mensae that found widespread evidence of ice lying beneath a few meters of rock debris.<ref>http://news.discovery.com/space/mars-ice-sheet-climate.html</ref> The ice was probably deposited as snowfall during an earlier climate when the poles were tilted more.<ref>Madeleine, J. et al.  2007.  Exploring the northern mid-latitude glaciation with a general circulation model.  In:  Seventh International Conference on Mars.  Abstract 3096.</ref>  It would be difficult to take a hike on the fretted terrain where glaciers are common because the surface is folded, pitted, and often covered with linear striations.<ref>http://www.uahirise.org/ESP_018857_2225</ref>  The striations show the direction of movement.  Much of this rough texture is due to sublimation of buried ice.  The ice goes directly into a gas (this process is called sublimation) and leaves behind an empty space.  Overlying material then collapses into the void.<ref>http://hirise.lpl.arizona.edu/PSP_009719_2230</ref>  Glaciers are not pure ice; they contain dirt and rocks.  At times, they will dump their load of materials into ridges.  Such ridges are called moraines.  
+
Glaciers formed much of the observable surface in large areas of Mars.  Much of the area in high latitudes, especially the Ismenius Lacus quadrangle, is believed to still contain enormous amounts of water ice.<ref>Hugh H. Kieffer (1992). Mars. University of Arizona Press. ISBN 978-0-8165-1257-7</ref> <ref> Plaut, J. et al. 2008. Radar Evidence for Ice in Lobate Debris Aprons in the Mid-Northern Latitudes of Mars. Lunar and Planetary Science XXXIX. 2290.pdf</ref> <ref>http://www.esa.int/SPECIALS/Mars_Express/SEMBS5V681F_0.html</ref>  In March 2010, scientists released the results of a radar study of an area called Deuteronilus Mensae that found widespread evidence of ice lying beneath a few meters of rock debris.<ref>http://news.discovery.com/space/mars-ice-sheet-climate.html</ref> The ice was probably deposited as snowfall during an earlier climate when the poles were tilted more.<ref>Madeleine, J. et al.  2007.  Exploring the northern mid-latitude glaciation with a general circulation model.  In:  Seventh International Conference on Mars.  Abstract 3096.</ref>  It would be difficult to take a hike on the fretted terrain where glaciers are common because the surface is folded, pitted, and often covered with linear striations.<ref>http://www.uahirise.org/ESP_018857_2225</ref>  The striations show the direction of movement.  Much of this rough texture is due to sublimation of buried ice.  The ice goes directly into a gas (this process is called sublimation) and leaves behind an empty space.  Overlying material then collapses into the void.<ref>http://hirise.lpl.arizona.edu/PSP_009719_2230</ref>  Glaciers are not pure ice; they contain dirt and rocks.  At times, they will dump their load of materials into ridges.  Such ridges are called moraines.  
  
 
<gallery class="center"  widths="380px" heights="360px">
 
<gallery class="center"  widths="380px" heights="360px">

Revision as of 12:53, 7 March 2020

Mars topography (MOLA dataset) HiRes (1).jpg
MC-05 Ismenius Lacus 30–65° N 0–60° E Quadrangles Atlas


This quadrangle has some of the most mysterious-looking landscapes on the planet. It truly looks like another world here. The Ismenius Lacus quadrangle contains regions called Deuteronilus Mensae and Protonilus Mensae, two places that are of special interest to scientists. They contain abundant evidence of present and past glacial activity. They also have a landscape unique to Mars, called Fretted terrain. The largest crater in the area is Lyot Crater, which contains channels probably carved by liquid water.[1] The Ismenius Lacus quadrangle is located in the northern hemisphere and covers 30° to 65° north latitude and 300° to 360° west longitude (60° to 0° east longitude). The southern and northern borders of the Ismenius Lacus quadrangle are approximately 3065 km (1,905 mi) and 1500 km wide (930 mi) respectively. The north-to-south distance is about 2050 km (1,270 mi) (a bit less than the length of Greenland).[2] The Ismenius Lacus quadrangle contains parts of regions named Acidalia Planitia, Arabia Terra, Vastitas Borealis, and Terra Sabaea.[3]

Origin of names

Ismenius Lacus is the name of a classical albedo feature located at 40° N and 30° E on Mars. The term is Latin for Ismenian Lake, and refers to the Ismenian Spring near Thebes in Greece where Cadmus slew the guardian dragon. Cadmus was the legendary founder of Thebes, and had come to the spring to fetch water. The name was approved by the International Astronomical Union (IAU) in 1958.[4] All names suggested for astronomical features have to eventually approved by the International Astronomical Union (IAU). Some important areas in this quadrangle derive from the names of canals that some early astronomers saw in this broad area. One such large canal they called Nilus. Since 1881–1882 it was split into other canals, some were called Nilosyrtis, Protonilus (first Nile),and Deuteronilus (second Nile).[5]

Channels (Rivers)

Many features were probably rivers with water flowing in them billions of years ago. Pictures below show many channels and parts of channels.


The channel shown below goes quite a long distance and has branches. It ends in a depression that may have been a lake at one time. The first picture is a wide angle, taken with CTX; while the second is a close up taken with HiRISE.[6]


Some places (like below) display a smaller channel within a larger, wider channel or valley. When this occurs it means water went through the region at least two times in the past. This implies that water was not here once for just a short period of time.

Lyot Crater

The vast northern plains of Mars are generally flat and smooth with few craters. However, a few large craters do stand out. The giant impact crater, Lyot, is easy to see in the northern part of Ismenius Lacus. There are only a very few craters along the far northern latitudes.[7] Lyot Crater is the deepest point in Mars's northern hemisphere.[8] One image below of Lyot Crater Dunes shows a variety of interesting forms: dark dunes, light-toned deposits, and Dust Devil Tracks. Dust devils, which resemble miniature tornados, create tracks by removing a thin, but bright deposit of dust to reveal the darker underlying surface. It does not take too much fine dust to cover those tracks--experiments in Earth laboratories demonstrate that only a few 10's of microns of dust will do the trick. Note on units: a micron is an older name for micrometre or micrometer. The width of a single human hair ranges from approximately 20 to 200 microns (μm); hence, the dust that can cover dust devil tracks may only be the thickness of a human hair.[9] Light-toned materials are an important find because they are widely believed to contain minerals formed in water. Research, published in June 2010, described evidence for liquid water in Lyot crater in the past.

Many channels have been found near Lyot Crater. Research, published in 2017, concluded that the channels were made from water released when the hot ejecta landed on a layer of ice that was 20 to 300 meters thick. Calculations suggest that the ejecta would have had a temperature of at least 250 degrees Fahrenheit. The valleys seem to start from beneath the ejecta near the outer edge of the ejecta. The existence of these channels is unusual because although Mars used to have water in rivers, lakes, and an ocean, these features have been dated to times after we had thought that many of these features had disappeared.[10] [11][12]

Other craters

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.[13] The peak is caused by a rebound of the crater floor following the impact.[14] Sometimes craters will display layers in their walls. Since the collision that produces a crater is like a powerful explosion, rocks from deep underground are tossed unto the surface. Hence, craters are useful for showing us what lies deep under the surface.

Fretted terrain

The Ismenius Lacus quadrangle contains several interesting features such as fretted terrain, parts of which are found in Deuteronilus Mensae and Protonilus Mensae. Fretted terrain contains smooth, flat lowlands along with steep cliffs. The scarps or cliffs are usually 1 to 2 km high. Channels in the area have wide, flat floors and steep walls. Many buttes and mesas are present. In fretted terrain the land seems to transition from narrow straight valleys to isolated mesas.[17] Most of the mesas are surrounded by forms that have been called a variety of names: circum-mesa aprons, debris aprons, rock glaciers, and lobate debris apron (LDA)s. The flat floors here often display many lines or lineations that scientists call lineated valley fill (LVF). These are cause by glacier-like flow. [18] At first they appeared to resemble rock glaciers on Earth. But scientists could not be sure. Even after the Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) took a variety of pictures of fretted terrain, experts could not tell for sure if material was moving or flowing as it would in an ice-rich deposit (glacier). Eventually, proof of their true nature was discovered by radar studies with the Mars Reconnaissance Orbiter showed that they contain pure water ice covered with a thin layer of rocks that insulated the ice.[19] [20]

Glaciers

Glaciers formed much of the observable surface in large areas of Mars. Much of the area in high latitudes, especially the Ismenius Lacus quadrangle, is believed to still contain enormous amounts of water ice.[21] [22] [23] In March 2010, scientists released the results of a radar study of an area called Deuteronilus Mensae that found widespread evidence of ice lying beneath a few meters of rock debris.[24] The ice was probably deposited as snowfall during an earlier climate when the poles were tilted more.[25] It would be difficult to take a hike on the fretted terrain where glaciers are common because the surface is folded, pitted, and often covered with linear striations.[26] The striations show the direction of movement. Much of this rough texture is due to sublimation of buried ice. The ice goes directly into a gas (this process is called sublimation) and leaves behind an empty space. Overlying material then collapses into the void.[27] Glaciers are not pure ice; they contain dirt and rocks. At times, they will dump their load of materials into ridges. Such ridges are called moraines.

See also

References

  1. Carter | first1 = J. | last2 = Poulet | first2 = F. | last3 = Bibring | first3 = J.-P. | last4 = Murchie | first4 = S. | year = 2010 | title = Detection of Hydrated Silicates in Crustal Outcrops in the Northern Plains of Mars | url = | journal = Science | volume = 328 | issue = 5986| pages = 1682–1686 |
  2. Distances calculated using NASA World Wind measuring tool. http://worldwind.arc.nasa.gov/.
  3. http://planetarynames.wr.usgs.gov/SearchResults?target=MARS&featureType=Terra,%20terrae
  4. USGS Gazetteer of Planetary Nomenclature. Mars. http://planetarynames.wr.usgs.gov/.
  5. Blunck, J. 1982. Mars and its Satellites. Exposition Press. Smithtown, N.Y.
  6. http://www.uahirise.org/ESP_039997_2170
  7. U.S. department of the Interior U.S. Geological Survey, Topographic Map of the Eastern Region of Mars M 15M 0/270 2AT, 1991
  8. http://space.com/scienceastronomy/090514--mars-rivers.html
  9. https://en.wikipedia.org/wiki/Micrometre
  10. doi=10.1002/2017GL073821 | volume=44 | issue=11 | title=Extensive Amazonian-aged fluvial channels on Mars: Evaluating the role of Lyot crater in their formation | journal=Geophysical Research Letters | pages=5336–5344 | last1 = Weiss | first1 = David K.|
  11. Weiss, D., et al. 2017. Extensive Amazonian-aged fluvial channels on Mars: Evaluating the role of Lyot crater in their formation. Geophysical Research Letters: 44, doi:10.1002/2017GL073821.
  12. http://spaceref.com/mars/hot-rocks-led-to-relatively-recent-water-carved-valleys-on-mars.html
  13. http://www.lpi.usra.edu/publications/slidesets/stones/
  14. Template:Cite book
  15. http://www.uahirise.org/epo/nuggets/expanded-secondary.pdf
  16. Viola, D., et al. 2014. EXPANDED CRATERS IN ARCADIA PLANITIA: EVIDENCE FOR >20 MYR OLD SUBSURFACE ICE. Eighth International Conference on Mars (2014). 1022pdf.
  17. Sharp, R. 1973. Mars Fretted and chaotic terrains. J. Geophys. Res.: 78. 4073–4083
  18. http://www.lpi.usra.edu/meetings/lpsc2000/pdf/1053.pdf
  19. Plaut, J. et al. 2008. Radar Evidence for Ice in Lobate Debris Aprons in the Mid-Northern Latitudes of Mars. Lunar and Planetary Science XXXIX. 2290.pdf
  20. Plaut | first1 = J. | last2 = Safaeinili | first2 = A. | last3 = Holt | first3 = J. | last4 = Phillips | first4 = R. | last5 = Head | first5 = J. | last6 = Seu | first6 = R. | last7 = Putzig | first7 = N. | last8 = Frigeri | first8 = A. | year = 2009 | title = Radar evidence for ice in lobate debris aprons in the midnorthern latitudes of Mars | url = https://semanticscholar.org/paper/f6b94761e6a276ce6894374ae9bea88fdc3e5e19%7C journal = Geophys. Res. Lett. | volume = 36| issue = 2| pages = n/a |
  21. Hugh H. Kieffer (1992). Mars. University of Arizona Press. ISBN 978-0-8165-1257-7
  22. Plaut, J. et al. 2008. Radar Evidence for Ice in Lobate Debris Aprons in the Mid-Northern Latitudes of Mars. Lunar and Planetary Science XXXIX. 2290.pdf
  23. http://www.esa.int/SPECIALS/Mars_Express/SEMBS5V681F_0.html
  24. http://news.discovery.com/space/mars-ice-sheet-climate.html
  25. Madeleine, J. et al. 2007. Exploring the northern mid-latitude glaciation with a general circulation model. In: Seventh International Conference on Mars. Abstract 3096.
  26. http://www.uahirise.org/ESP_018857_2225
  27. http://hirise.lpl.arizona.edu/PSP_009719_2230