Yardangs are common in some regions on Mars, especially in what's called the "Medusae Fossae Formation." This formation is found in the Amazonis quadrangle and near the equator.[1] 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.[2] Because they exhibit very few impact craters they are believed to be relatively young.[3] The easily eroded nature of the Medusae Fossae Formation suggests that it is composed of weakly cemented particles, and was most likely formed by the deposition of wind-blown dust or volcanic ash. Yardangs are parts of rock that have been sand blasted into long, skinny ridges by bouncing sand particles blowing in the wind.[4][5] Layers are seen in parts of the formation. A resistant caprock on the top of yardangs has been observed in Viking,[6] Mars Global Surveyor,[7] and HiRISE photos.[8] Images from spacecraft show that they have different degrees of hardness probably because of significant variations in the physical properties, composition, particle size, and/or cementation.
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Medusae Fossae Formation as seen with Mars Odyssey's THEMIS. Notice elongated formations called yardangs.
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Yardangs in Medusae Fossae Formation with caprock labeled, as seen by HiRISE. Location is Aeolis quadrangle.
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Yardangs near a crater, as seen by HiRISE under HiWish program Location is in the Amazonis quadrangle.
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Yardangs, as seen by HiRISE under HiWish program Location is near Gordii Dorsum in the Amazonis quadrangle. These yardangs are in the upper member of the Medusae Fossae Formation.
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Yardangs showing layers, as seen by HiRISE under HiWish program Location is Aeolis quadrangle.
See also
References
- ^ SAO/NASA ADS Astronomy Abstract Service: Yardangs on Mars
- ^ http://www.esa.int/Our_Activities/Space_Science/Mars_Express/Yardangs_on_Mars
- ^ http://themis.asu.edu/zoom-20020416a
- ^ http://www.uahirise.org/ESP_039563_1730
- ^ http://www.uahirise.org/ESP_039563_1730
- ^ Scott, David H.; Tanaka, Kenneth L. (1982). "Ignimbrites of Amazonis Planitia Region of Mars". Journal of Geophysical Research 87: 1179–1190. Bibcode:1982JGR....87.1179S. doi:10.1029/JB087iB02p01179.
- ^ Malin, MC; Carr, MH; Danielson, GE; Davies, ME; Hartmann, WK; Ingersoll, AP; James, PB; Masursky, H; et al. (March 1998). "Early views of the martian surface from the Mars Orbiter Camera of Mars Global Surveyor". Science 279 (5357): 1681–5. Bibcode:1998Sci...279.1681M. doi:10.1126/science.279.5357.1681. PMID 9497280.
- ^ Mandt, Kathleen E.; De Silva, Shanaka L.; Zimbelman, James R.; Crown, David A. (2008). "The origin of the Medusae Fossae Formation, Mars: Insights from a synoptic approach". Journal of Geophysical Research 113: 12011. Bibcode:2008JGRE..11312011M. doi:10.1029/2008JE003076. hdl:10088/7052.