Casius quadrangle

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Casius quadrangle
USGS-Mars-MC-6-CasiusRegion-mola2.png
Map of Casius quadrangle from Mars Orbiter Laser Altimeter (MOLA) data. The highest elevations are red and the lowest are blue.
Coordinates 47°30′N 270°00′W / 47.5°N 270°W / 47.5; -270Coordinates: 47°30′N 270°00′W / 47.5°N 270°W / 47.5; -270
Image of the Casius Quadrangle (MC-6). The southwest area contains Nilosyrtis Mensae (faults, measa and buttes); the rest of the area is mostly smooth plains.

The Casius quadrangle is one of a series of 30 quadrangle maps of Mars used by the United States Geological Survey (USGS) Astrogeology Research Program. The quadrangle is located in the north central portion of Mars’ eastern hemisphere and covers 60° to 120° east longitude (240° to 300° west longitude) and 30° to 65° north latitude. The quadrangle uses a Lambert conformal conic projection at a nominal scale of 1:5,000,000 (1:5M). The Casius quadrangle is also referred to as MC-6 (Mars Chart-6).[1] The southern and northern borders of the Casius quadrangle are approximately 3,065 km and 1,500 km wide, respectively. The north to south distance is about 2,050 km (slightly less than the length of Greenland).[2] The quadrangle covers an approximate area of 4.9 million square km, or a little over 3% of Mars’ surface area.[3]

Contents

Origin of Name [edit]

Casius is the name of a telescopic albedo feature located at 40° N and 100° E on Mars. The feature was named for the Latin epithet for Zeus from his sanctuaries in Egypt and Syria. The name was approved by the International Astronomical Union (IAU) in 1958.[4]

Physiography and Geology [edit]

The high latitude Casius quadrangle bears several features that are believed to indicate the presence of ground ice. Patterned ground is one such feature. Usually, polygonal shapes are found poleward of 55 degrees latitude.[5] Other features associated with ground ice are Scalloped Topography,[6] Ring Mold Craters, and Concentric Crater Fill.

  • Map of Casius quadrangle with major features labeled.

  • Patterned ground in the form of polygonal features is associated with ground ice. It is rare to be found this far south (45 degrees north latitude). Picture taken by Mars Global Surveyor.

  • Periglacial Forms in Utopia, as seen by HiRISE. Click on image to see patterned ground and Scalloped Topography.

Nilosyrtis [edit]

Nilosyrtis runs from about 280 to 304 degrees west longitude, so like several other features, it sits in more than one quadrangle. Part of Nilosyrtis is in the Ismenius Lacus quadrangle, the rest is in Casius quadrangle.

  • Channel in Nilosyrtis that was formed when a lake in a 45 mile wide crater drained, as seen by THEMIS.

  • Landing Site in Nilosyrtis, as seen by THEMIS. Site is flat and contains water-altered clay minerals.

  • Nilosyrtis, as seen by HiRISE. Click on image to see layers.

Ring Mold Craters [edit]

Ring Mold Craters look like the ring molds used in baking. They are believed to be caused by an impact into ice. The ice is covered by a layer of debris. They are found in parts of Mars that have buried ice. Laboratory experiments confirm that impacts into ice result in a "ring mold shape."[7][8][9] They may be an easy way for future colonists of Mars to find water ice.

  • CTX context image for next image taken with HiRISE. Box indicates image footprint of following image.

  • Possible ring mold crater, as seen by HiRISE under the HiWish program. Crater shape is due to impact into ice.

Concentric Crater Fill [edit]

Concentric crater fill is when the floor of a crater is mostly covered with a large number of parallel ridges.[10] They are thought to result from a glacial type of movement.[11][12] Sometimes boulders are found on concentric crater fill; it is believed they fell off crater wall, and then were transported away from the wall with the movement of the glacier.[13][14]Erratics on Earth were carried by similar means. Based on accurate topography measures of height at different points in these craters and calculations of how deep the craters should be based on their diameters, it is thought that the craters are 80% filled with mostly ice. That is, they hold hundreds of meters of material that probably consists of ice with a few tens of meters of surface debris.[15] The ice accumulated in the crater from snowfall in previous climates.[16]

High resolution pictures taken with HiRISE reveal that some of the surfaces of concentric crater fill are covered with strange patterns called closed-cell and open-cell brain terrain. The terrain resembles a human brain. It is believed to be caused by cracks in the surface accumulating dust and other debris, together with ice sublimating from some of the surfaces.[17]

  • Wide-view of concentric crater fill, as seen by HiRISE.

  • Concentric Crater Fill Close-up of near the top of previous image, as seen by HiRISE. The surface debris covers water ice.

  • Well-developed hollows of concentric crater fill, as seen by HiRISE under the HiWish program.

  • Close-up that shows cracks containing pits on the floor of a crater containing concentric crater fill, as seen by HiRISE under HiWish program.

  • Close-up that shows cracks containing pits on the floor of a crater, as seen by HiRISE under HiWish program. Cracks may start as a line of pits that enlarge, then join.

Mars Science Laboratory [edit]

Nilosyrtis is one of the sites proposed as a landing site for the Mars Science Laboratory. However, it did not make the final cut. It was in the top 7, but not in the top 4. The aim of the Mars Science Laboratory is to search for signs of ancient life. It is hoped that a later mission could then return samples from sites identified as probably containing remains of life. To safely bring the craft down, a 12 mile wide, smooth, flat circle is needed. Geologists hope to examine places where water once ponded.[18] They would like to examine sediment layers.

Other Views from Casius [edit]

  • Crater in the Adamas Labyrinthus Region, as seen by HiRISE. The original image shows many interesting details.

  • Bacolor Crater Ejecta, as seen by HiRISE. Scale bar is 1000 meters long.

  • Astapus Colles Mounds and Knobs, as seen by HiRISE. Scale bar is 500 meters long.

  • Surface of Nilosyrtis Mensae showing ridges and cracks, as seen by HiRISE, under the HiWish program.

  • Another view of surface of Nilosyrtis Mensae, as seen by HiRISE, under the HiWish program.

  • CTX image showing area in next image.

  • Layers in craters, as seen by HiRISE under the HiWish program. Area was probably covered over by these layers; the layers have now eroded away except for the protected interior of craters.

  • Layers, as seen by HiRISE under HiWish program.

  • 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.

  • Dikes as seen by HiRISE under the HiWish program.

  • Pits that seem to be forming cracks, as seen by HiRISE under HiWish program.

  • Holes and hollows on crater floor, as seen by HiRISE under HiWIsh program.

See also [edit]

References [edit]

  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. ^ Distances calculated using NASA World Wind measuring tool. http://worldwind.arc.nasa.gov/.
  3. ^ Approximated by integrating latitudinal strips with area of R^2 (L1-L2)(cos(A)dA) from 30° to 65° latitude; where R = 3889 km, A is latitude, and angles expressed in radians. See: http://stackoverflow.com/questions/1340223/calculating-area-enclosed-by-arbitrary-polygon-on-earths-surface.
  4. ^ USGS Gazetteer of Planetary Nomenclature. Mars. http://planetarynames.wr.usgs.gov/.
  5. ^ Mangold, N. 2005. High latitude paterned grounds on Mars: Classification, distribution and climatic control. Icarus. 174-336-359.
  6. ^ http://hiroc.lpl.arizona.edu/images/PSP/diafotizo.php?ID=PSP_002296_1215
  7. ^ Kress, A., J. Head. 2008. Ring-mold craters in lineated valley fill and lobate debris aprons on Mars: Evidence for subsurface glacial ice. Geophys.Res. Lett: 35. L23206-8
  8. ^ Baker, D. et all. 2010. Flow patterns of lobate debris aprons and lineated valley fill north of Ismeniae Fossae, Mars: Evidence for extensive mid-latitude glaciation in the Late Amazonian. Icarus: 207. 186-209
  9. ^ Kress., A. and J. Head. 2009. Ring-mold craters on lineated valley fill, lobate debris aprons, and concentric crater fill on Mars: Implications for near-surface structure, composition, and age. Lunar Planet. Sci: 40. abstract 1379
  10. ^ http://hiroc.lpl.arizona.edu/images/PSP/diafotizo.php?ID=PSP_111926_2185
  11. ^ Head, J. et al. 2006. Extensive valley glacier deposits in the northern mid-latitudes of Mars: Evidence for late Amazonian obliquity-driven climate change. Earth Planet. Sci Lett: 241. 663-671.
  12. ^ Levy, J. et al. 2007. Lineated valley fill and lobate debris apron stratigraphy in Nilosyrtis Mensae, Mars: Evidence for phases of glacial modification of the dichotomy boundary. J. Geophys. Res: 112.
  13. ^ Marchant, D. et al. 2002. Formation of patterned ground and sublimation till over Miocene glacier ice in Beacon valley, southern Victorialand, Antarctica. Geol. Soc. Am. Bull:114. 718-730.
  14. ^ Head, J. and D. Marchant. 2006. Modification of the walls of a Noachian crater in northern Arabia Terra (24E, 39N) during mid-latitude Amazonian glacial epochs on Mars: Nature and evolution of lobate debris aprons and their relationships to lineated valley fill and glacial systems. Lunar Planet. Sci: 37. Abstract # 1126.
  15. ^ Garvin, J. et al. 2002. Global geometric properties of martian impact craters. Lunar Planet. Sci: 33. Abstract # 1255.
  16. ^ Kreslavsky, M. and J. Head. 2006. Modification of impact craters in the northern planes of Mars: Implications for the Amazonian climate history. Meteorit. Planet. Sci.: 41. 1633-1646
  17. ^ Ley, J. et al. 2009. Concentric crater fill in Utopia Planitia: History and interaction between glacial "brain terrain" and periglacial processes. Icarus: 202. 462-476.
  18. ^ http://themis.asu.edu/features/ianichaos
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