Sinus Sabaeus quadrangle

Wislicenus Crater and the Schiaparelli basin crater contains layers, also called strata. Many places on Mars show rocks arranged in layers.Grotzinger, J. and R. Milliken (eds.) 2012. Sedimentary Geology of Mars. SEPM 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. Some layers are probably made up of fine particles because they seem to break up into fine dust. Other layers break up into large boulders so they are probably much harder. Basalt, a volcanic rock, is thought to in the layers that form boulders. Basalt has been identified on Mars in many places. Instruments on orbiting spacecraft have detected clay (also called phyllosilicates) in some layers. Scientists are excited about finding hydrated minerals such as sulfates and clays on Mars because they are usually formed in the presence of water.{{Cite web|url=http://themis.asu.edu/features/nilosyrtis|title = Target Zone: Nilosyrtis? | Mars Odyssey Mission THEMIS}} Places that contain clays and/or other hydrated minerals would be good places to look for evidence of life.{{Cite web|url=http://hirise.lpl.arizona.edu/PSP_004046_2080|title=HiRISE | Craters and Valleys in the Elysium Fossae (PSP_004046_2080)}}

Rock can form layers in a variety of ways. Volcanoes, wind, or water can produce layers.{{Cite web|url=https://hirise.lpl.arizona.edu/?PSP_008437_1750|title=HiRISE | High Resolution Imaging Science Experiment|website=hirise.lpl.arizona.edu}} Layers can be hardened by the action of groundwater. Martian ground water probably moved hundreds of kilometers, and in the process it dissolved many minerals from the rock it passed through. When ground water surfaces in low areas containing sediments, water evaporates in the thin atmosphere and leaves behind minerals as deposits and/or cementing agents. Consequently, layers of dust could not later easily erode away since they were cemented together. On Earth, mineral-rich waters often evaporate forming large deposits of various types of salts and other minerals. Sometimes water flows through Earth's aquifers, and then evaporates at the surface just as is hypothesized for Mars. One location this occurs on Earth is the Great Artesian Basin of Australia.Habermehl, M. A. (1980) The Great Artesian Basin, Australia. J. Austr. Geol. Geophys. 5, 9–38. On Earth the hardness of many sedimentary rocks, like sandstone, is largely due to the cement that was put in place as water passed through.

File:ESP 046814 1785schiaparellimola.jpg

Schiaparelli is an impact crater on Mars located near Mars's equator. It is {{convert|461|km|mi|sp=us}} in diameter and located at latitude 3° south and longitude 344°. Some places within Schiaparelli show many layers that may have formed by the wind, volcanoes, or deposition under water.

When a comet or asteroid collides at a high speed interplanetary with the surface of Mars it creates a primary impact crater. The primary impact may also eject significant numbers of rocks which eventually fall back to make secondary craters.{{Cite web|url=http://hirise.lpl.arizona.edu/science_themes/impact.php|title = HiRISE | Science Themes: Impact Processes}} The secondary craters may be arranged in clusters. All of the craters in the cluster would appear to be equally eroded; indicating that they would all are of the same age. If these secondary craters formed from a single, large, nearby impact, then they would have formed at roughly the same instant in time. The image below of Denning Crater shows a cluster of secondary 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.{{Cite web|url=http://www.lpi.usra.edu/publications/slidesets/stones/|title=Stones, Wind, and Ice: A Guide to Martian Impact Craters}} The peak is caused by a rebound of the crater floor following the impact.{{cite book|author=Hugh H. Kieffer|title=Mars|url=https://books.google.com/books?id=NoDvAAAAMAAJ|access-date=7 March 2011|date=1992|publisher=University of Arizona Press|isbn=978-0-8165-1257-7}} If one measures the diameter of a crater, the original depth can be estimated with various ratios. Because of this relationship, researchers have found that many Martian craters contain a great deal of material; much of it is believed to be ice deposited when the climate was different.Garvin, J., et al. 2002. Global geometric properities of martian impact craters. Lunar Planet Sci. 33. Abstract @1255. Sometimes craters expose layers that were buried. Rocks from deep underground are tossed onto the surface. Hence, craters can show us what lies deep under the surface.

File:Whiterock.JPG.]]

Within the region is Pollack crater, which has light-toned rock deposits. Mars has an old surface compared to Earth. While much of Earth's land surface is just a few hundred million years old, large areas of Mars are billions of years old. Some surface areas have been formed, eroded away, then covered over with new layers of rocks. The Mariner 9 spacecraft in the 1970s photographed a feature that was called "White Rock". Newer images revealed that the rock is not really white, but that the area close by is so dark that the white rock looks really white. It was thought that this feature could have been a salt deposit, but information from the instruments on Mars Global Surveyor demonstrated rather that it was probably volcanic ash or dust. Today, it is believed that White Rock represents an old rock layer that once filled the whole crater that it is in, but today it has since been mostly eroded away. The picture below shows white rock with a spot of the same rock some distance from the main deposit, so it is thought that the white material once covered a far larger area.{{Cite web|url=http://space.com/scienceastronomy/solarsystem/mars_daily_020419.html|title = Mars: What We Know About the Red Planet|website = Space.com|date = October 2021}}

There is enormous evidence that water once flowed in river valleys on Mars.Baker, V., et al. 2015. Fluvial geomorphology on Earth-like planetary surfaces: a review. Geomorphology. 245, 149–182.Carr, M. 1996. in Water on Mars. Oxford Univ. Press. Images of curved channels have been seen in images from Mars spacecraft dating back to the early 1970s with the Mariner 9 orbiter.Baker, V. 1982. The Channels of Mars. Univ. of Tex. Press, Austin, TXBaker, 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.Carr, M. 1979. Formation of Martian flood features by release of water from confined aquifers. J. Geophys. Res. 84, 2995–300.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. Indeed, a study published in June 2017, calculated that the volume of water needed to carve all the channels on Mars was even larger than the proposed ocean that the planet may have had. Water was probably recycled many times from the ocean to rainfall around Mars.{{Cite web|url=http://spaceref.com/mars/how-much-water-was-needed-to-carve-valleys-on-mars.html|title = How Much Water Was Needed to Carve Valleys on Mars? - SpaceRef| date=5 June 2017 }}Luo, W., et al. 2017. New Martian valley network volume estimate consistent with ancient ocean and warm and wet climate. Nature Communications 8. Article number: 15766 (2017). doi:10.1038/ncomms15766

{{Main|Valley networks (Mars)}}

{{Main|Outflow channels}}

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• Climate of Mars
• Dike (geology)
• Geology of Mars
• Groundwater on Mars
• HiRISE
• HiWish program
• Impact crater
• List of quadrangles on Mars
• Martian Craters
• Valley network (Mars)
• Vallis
• Water on Mars

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{{reflist|colwidth=30em}}

• Grotzinger, J. and R. Milliken (eds.). 2012. Sedimentary Geology of Mars. SEPM.

{{commons category|Sinus Sabaeus quadrangle}}

{{Mars quadrangle layout}}

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Category:Mars