Sinus Sabaeus quadrangle
Encyclopedia
The Sinus Sabaeus quadrangle
Quadrangle (geography)
In geology or geography, the word "quadrangle" usually refers to a United States Geological Survey 7.5-minute quadrangle map, which are usually named after a local physiographic feature. The shorthand "quad" is also used, especially with the name of the map; for example, "the Ranger Creek, Texas...

is one of a series of 30 quadrangle maps of Mars used by the United States Geological Survey
United States Geological Survey
The United States Geological Survey is a scientific agency of the United States government. The scientists of the USGS study the landscape of the United States, its natural resources, and the natural hazards that threaten it. The organization has four major science disciplines, concerning biology,...

 (USGS) Astrogeology Research Program
Astrogeology Research Program
The USGS Astrogeology Science Center has a rich history of participation in space exploration efforts and planetary mapping, starting in 1963 when the Flagstaff Science Center was established by Gene Shoemaker to provide lunar geologic mapping and assist in training astronauts destined for the...

. It is also referred to as MC-20 (Mars Chart-20).

The Sinus Sabaeus quadrangle covers the area from 315° to 360° west longitude and 0° to 30° degrees south latitude on Mars
Mars
Mars is the fourth planet from the Sun in the Solar System. The planet is named after the Roman god of war, Mars. It is often described as the "Red Planet", as the iron oxide prevalent on its surface gives it a reddish appearance...

. It contains Schiaparelli, a large, easily visible crater that sits close to the equator.

White rock in Pollack crater

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
Mariner 9
Mariner 9 was a NASA space orbiter that helped in the exploration of Mars and was part of the Mariner program. Mariner 9 was launched toward Mars on May 30, 1971 from Cape Canaveral Air Force Station and reached the planet on November 13 of the same year, becoming the first spacecraft to orbit...

 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
Mars Global Surveyor
The Mars Global Surveyor was a US spacecraft developed by NASA's Jet Propulsion Laboratory and launched November 1996. It began the United States's return to Mars after a 10-year absence. It completed its primary mission in January 2001 and was in its third extended mission phase when, on 2...

 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's 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.
Pollack crater's white rocks:

Layers

Wislicenus Crater
Wislicenus Crater
Wislicenus Crater is an impact crater in the Sinus Sabaeus quadrangle of Mars at 18.4° south latitude and 348.6° west longitude. It is about 139 km in diameter and was named after Walter Wislicenus, a German astronomer .- Layers :...

 and the Schiaparelli basin crater contains layers, also called strata. Many places on Mars show rocks arranged in layers. Sometimes the layers are of different colors. Light-toned rocks on Mars have been associated with hydrated minerals like sulfates. The Mars Rover
Mars Rover
A Mars rover is an automated motor vehicle which propels itself across the surface of the planet Mars after landing.Rovers have several advantages over stationary landers: they examine more territory, they can be directed to interesting features, they can place themselves in sunny positions to...

 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 find dust. Other layers break up into large boulders so they are probably much harder. Basalt
Basalt
Basalt is a common extrusive volcanic rock. It is usually grey to black and fine-grained due to rapid cooling of lava at the surface of a planet. It may be porphyritic containing larger crystals in a fine matrix, or vesicular, or frothy scoria. Unweathered basalt is black or grey...

, 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
Clay
Clay is a general term including many combinations of one or more clay minerals with traces of metal oxides and organic matter. Geologic clay deposits are mostly composed of phyllosilicate minerals containing variable amounts of water trapped in the mineral structure.- Formation :Clay minerals...

 (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. Places that contain clays and/or other hydrated minerals would be good places to look for evidence of life.

Rock can form layers in a variety of ways. Volcanoes, wind, or water can produce layers.

Craters

When a comet
Comet
A comet is an icy small Solar System body that, when close enough to the Sun, displays a visible coma and sometimes also a tail. These phenomena are both due to the effects of solar radiation and the solar wind upon the nucleus of the comet...

 or asteroid
Asteroid
Asteroids are a class of small Solar System bodies in orbit around the Sun. They have also been called planetoids, especially the larger ones...

 collides at a high rate of 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. 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 Dennin Crater
Denning (Martian crater)
Denning Crater is a crater in the Sinus Sabaeus quadrangle of Mars at 17.7° south latitude and 326.6° west longitude. It is about 165 km in diameter and was named after William F. Denning, a British astronomer .- Craters :...

  shows a cluster of secondary craters.

See also

  • Climate of Mars
    Climate of Mars
    The climate of Mars has been an issue of scientific curiosity for centuries, not least because Mars is the only terrestrial planet whose surface can be directly observed in detail from the Earth....

  • Water on Mars
    Water on Mars
    Water on Mars is a psychedelic rock and electronic music group from Quebec City, Québec, Canada. The music trio is led by Philippe Navarro, guitarist, vocalist, arranger, producer, principal lyricist, and music composer....

  • Geology of Mars
    Geology of Mars
    The geology of Mars is the scientific study of the surface, crust, and interior of the planet Mars. It emphasizes the composition, structure, history, and physical processes that shape the planet. It is fully analogous to the field of terrestrial geology. In planetary science, the term geology is...

  • Vallis
    Vallis
    Vallis is the Latin word for valley. It is used in planetary geology for the naming of landform features on other planets....

  • Impact crater
    Impact crater
    In the broadest sense, the term impact crater can be applied to any depression, natural or manmade, resulting from the high velocity impact of a projectile with a larger body...

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