The Oxia Palus quadrangle is one of a series of 30 quadrangle maps of Mars used by the United States Geological Survey (USGS) Astrogeology Research Program. The Oxia Palus quadrangle is also referred to as MC-11 (Mars Chart-11).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.
The quadrangle covers the region of 0° to 45° west longitude and 0° to 30° north latitude on Mars. This quadrangle contains parts of multiple regions: Chryse Planitia, Arabia Terra, Xanthe Terra, Margaritifer Terra, Meridiani Planum and Oxia Planum.
Mars Pathfinder landed in the Oxia Palus quadrangle at , on July 4, 1997, at the intersection Tiu Valles and Ares Vallis.
Many craters within Oxia Palus are named after famous scientists. Besides Galilei and da Vinci, some of the people who discovered the atom and radiation are honored there: Curie, Becquerel, and Rutherford.U.S. department of the Interior U.S. Geological Survey, Topographic Map of the Eastern Region of Mars M 15M 0/270 2AT, 1991
Mawrth Vallis was strongly considered as a landing site for NASA's Curiosity rover, the Mars Science Laboratory.https://www.space.com/missionlaunches/mars-science-laboratory-curiosity-landing-sites-100615.htm It made it to at least the top two sites for NASA's EXoMars 2020 Rover mission. The exact location proposed for this landing is 22.16 N and 342.05 E.
The Mawrth Vallis region is well studied with more than 40 papers published in peer-reviewed publications. Near the Mawrth channel is a 200 meter high plateau with a number of exposed layers. Spectral studies have detected clay minerals that present as a sequence of layers.Loizeau et al. 2007. JGR 112, E08S08Noe Dobrea et al. 2010. JGR 115, E00D19Michalski, Noe Dobrea. 2007. Geol. 35, 10. Clay minerals were probably deposited in the Early to Middle Noachian period. Later weathering exposed a variety of minerals such as kaolin, alunite, and jarosite. Later, volcanic material covered the region. This volcanic material would have protected any possible organic materials from radiation.Gross, C. et al. 2016. MAWRTH VALLIS – PROPOSED LANDING SITE FOR EXOMARS 2018/2020. 47th Lunar and Planetary Science Conference (2016) 1421.pdf
Another site in the Oxia Palus quadrangle has been picked for the EXoMars 2020 landing is at 18.14 N and 335.76 E. This site is of interest because of a long-duration aqueous system including a delta, possible biosignatures, and a variety of clays.] Quantin C. et al. (2014) ExoMars LSSW#1
This quadrangle contains abundant evidence for past water in such forms as river valleys, lakes, springs, and chaos areas where water flowed out of the ground. A variety of clay minerals have been found in Oxia Palus. Clay is formed in water, and it is good for preserving microscopic evidence of ancient life.http://themis.asu.edu/features/marwrthvillis Recently, scientists have found strong evidence for a lake located in the Oxia Palus quadrangle that received drainage from Shalbatana Vallis. The study, carried out with HiRISE images, indicates that water formed a 30-mile-long canyon that opened up into a valley, deposited sediment, and created a delta. This delta and others around the basin imply the existence of a large, long-lived lake. Of special interest is evidence that the lake formed after the warm, wet period was thought to have ended. So, lakes may have been around much longer than previously thought. In October 2015, Oxia Planum, a plain located near , was reported to be the preferred landing location for the ExoMars rover. An erosion-resistant layer on top of clay units may have preserved evidence of life.Quantin, C. et al. 2015. EPSC2015-704Quantin C. et al. (2015) ExoMars LSSW#
Surface appearance
The Mars Pathfinder found its landing site to contain a great deal of rocks. Analysis shows the area to have a greater density of rocks than 90% of Mars. Some of the rocks leaned against each other in a manner geologists term imbricated. It is believed strong flood waters in the past pushed the rocks around to face away from the flow. Some pebbles were rounded, perhaps from being tumbled in a stream. Some rocks have holes on their surfaces that seem to have been fluted by wind action. Small sand dunes are present. Parts of the ground are crusty, maybe due to cementing by a fluid containing minerals. In general the rocks show a dark gray color with patches of red dust or weathered appearance on their surfaces. Dust covers the lower 5–7 cm of some rocks, so they may have once been buried, but have now become exhumed. Three knobs, one large crater, and two small craters were visible on the horizon.Golombek, M. et al. 1997. Overview of the Mars Pathfinder Mission and Assessment of Landing Site Predictions. Science: 278. pp. 1743–1748
Types of rocks Results of Mars Pathfinder's Alpha Proton X-ray Spectrometer indicated that some rocks in the Oxia Palus quadrangle are like Earth's andesites. The discovery of andesites shows that some Martian rocks have been remelted and reprocessed. On Earth, Andesite forms when magma sits in pockets of rock while some of the iron and magnesium settle out. Consequently, the final rock contains less iron and magnesium and more silica. Volcanic rocks are usually classified by comparing the relative amount of alkalis (Na2O and K2O) with the amount of silica (SiO2). Andesite is different from the rocks found in meteorites that have come from Mars.Bruckner, J., G. Dreibus, R. Rieder, and H. Wanke. 2001. Revised Data of the Mars Pathfinder Alpha Proton X-ray spectrometer: Geochemical Behavior of Major and Minor Elements. Lunar and Planetary Science XXXII
By the time that final results of the mission were described in a series of articles in the journal Science (December 5, 1997), it was believed that the rock Yogi contained a coating of dust, but was similar to the rock Barnacle Bill. Calculations suggest that the two rocks contain mostly the minerals orthopyroxene (magnesium-iron silicate), feldspars (aluminum silicates of potassium, sodium, and calcium), quartz (silicon dioxide), with smaller amounts of magnetite, ilmenite, iron sulfide, and calcium phosphate.
Other results from Pathfinder By taking multiple images of the sky at different distances from the sun, scientists were able to determine that size of the particles in the pink haze was about 1 micrometer in radius. The color of some soils was similar to that of an iron oxyhydroxide phase which would support a warmer and wetter climate in the past.Smith, P. et al. 1997. Results from the Mars Pathfinder Camera Science: 278. 1758-1765 Pathfinder carried a series of magnets to examine the magnetic component of the dust. Eventually, all but one of the magnets developed a coating of dust. Since the weakest magnet did not attract any soil, it was concluded that the airborne dust did not contain pure magnetite or one type of maghemite. The dust probably was an aggregate possible cemented with ferric oxide (Fe2O3).Hviid, S. et al. 1997. Magnetic Properties Experiments on the Mars Pathfinder Lander: Preliminary Results. Science:278. 1768-1770.
Winds were usually less than 10 m/s. Dust devils were detected in the early afternoon. The sky had a pink color. There was evidence of clouds and maybe fog.
River valleys and chaos
Many large, ancient river valleys are found in this area; along with collapsed features, called Chaos. The Chaotic features may have collapsed when water came out onto the surface. Martian rivers begin with a Chaos region. A chaotic region can be recognized by a rat's nest of mesas, buttes, and hills, chopped through with valleys which in places look almost patterned. Some parts of this chaotic area have not collapsed completely—they are still formed into large mesas, so they may still contain water ice. Chaotic terrain occurs in multiple locations on Mars, and always gives the strong impression that something abruptly disturbed the ground. More information and more examples of chaos can be found at Chaos terrain. Chaos regions formed long ago. By counting craters (more craters in any given area means an older surface) and by studying the valleys' relations with other geological features, scientists have concluded the channels formed 2.0 to 3.8 billion years ago.
One generally accepted view for the formation of large outflow channels is that they were formed by catastrophic floods of water released from giant groundwater reservoirs. Perhaps, the water started to come out of the ground due to faulting or volcanic activity. Sometimes hot magma just travels under the surface. If that is the case, the ground will be heated, but there may be no evidence of lava at the surface. After water escapes, the surface collapses. Moving across the surface, the water would have simultaneously frozen and evaporated. Chunks of ice that would have rapidly formed may have enhanced the erosive power of the flood. Furthermore, the water may have frozen over at the surface, but continuing to flow underneath, eroding the ground as it moved along. Rivers in cold climates on the Earth often become ice-covered, yet continue to flow.
Such catastrophic floods have occurred on Earth. One commonly cited example is the Channeled Scabland of Washington State; it was formed by the breakout of water from the Pleistocene Lake Missoula. This region resembles the Martian outflow channels.
Lakes Research, published in January 2010, suggests that Mars had lakes, each around 20 km wide, along parts of the equator, in the Oxia Palus quadrangle. Although earlier research showed that Mars had a warm and wet early history that has long since dried up, these lakes existed in the Hesperian Epoch, which was a much earlier period. Using detailed images from NASA's Mars Reconnaissance Orbiter, the researchers speculate that there may have been increased volcanic activity, meteorite impacts, or shifts in Mars' orbit during this period to warm Mars' atmosphere enough to melt the abundant ice present in the ground. Volcanoes would have released gases that thickened the atmosphere for a temporary period, trapping more sunlight and making it warm enough for liquid water to exist. In this new study, channels were discovered that connected lake basins near Ares Vallis. When one lake filled up, its waters overflowed the banks and carved the channels to a lower area where another lake formed.Sanjeev Gupta, Nicholas Warner, Jung-Rack Kim, Shih-Yuan Lin, Jan Muller. 2010. Hesperian equatorial thermokarst lakes in Ares Vallis as evidence for transient warm conditions on Mars. Geology: 38. 71-74. These lakes would be another place to look for evidence of present or past life.
Aram Chaos