Sinus Sabaeus quadrangle

The Sinus Sabaeus quadrangle (geography), quadrangle is one of a series of list of quadrangles on Mars, 30 quadrangle maps of Mars used by the United States Geological Survey (USGS) Astrogeology Research Program. 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. It contains Schiaparelli (crater on Mars), Schiaparelli, a large, easily visible crater that sits close to the equator. The Sinus Sabaeus quadrangle contains parts of Noachis Terra and Terra Sabaea.

The name comes from an incense-rich location south of the Arabian peninsula (the Gulf of Aden).

Layers

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 (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. 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. 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. 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.

Image:Wislicenus Crater Floor.JPG, Wislicenus Crater Floor, as seen by HiRISE. Erosion on floor has made layers visible.
Image:Bouguer Crater from CTX.JPG, Bouguer (Martian crater) as seen by CTX. Crater rim is at top. Small craters are on floor of the crater.
Image:Bouguercraterhirise.jpg, Close up of layers in eroded deposits on the floor of Bouguer Crater, as seen by HiRISE. This image is in a different part of the crater than the previous image.
Image:Layers in Monument Valley.jpg, 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.
Image:26876whitelayers.jpg, White layers that may be related to the white material in Pollack Crater, as seen by HiRISE under HiWish program.

Schiaparelli Crater

Schiaparelli is an impact crater on Mars located near Mars's equator. It is 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.

ESP 046814 1785schiaparellimola.jpg, MOLA map of area around Schiaparelli Crater
Image:Schiaparelli Crater Layers.JPG, Layers in Crater within Schiaparelli (Martian crater), Schiaparelli crater, as seen by HiRISE
Image:Schiaparelli basin crater.jpg, Layers in crater found within the Schiaparelli (Martian crater), Schiaparelli crater basin as seen by Mars Global Surveyor
Image:ESP 025201rings.jpg, Circular structures on floor of Schiaparelli Crater, as seen by HiRISE under HiWish program
Image:25201ringclose.jpg, Close-up of circular structure from previous image, as seen by HiRISE under HiWish program Streaks are also visible.
Image:ESP 028511rings.jpg, Circular structures on floor of Schiaparelli Crater, as seen by HiRISE under HiWish program
ESP 046814 context.jpg, Context view for following picture. Picture taken with CTX.
ESP 046814 1785layerswide.jpg, Wide view of layers in Schiaparelli Crater, as seen by HiRISE under HiWish program Part of the picture is degraded. Parts of this image are enlarged in other images that follow.
46814 1785layeredmound.jpg, Layered mound in Schiaparelli Crater, as seen by HiRISE under HiWish program
46814 1785layeredmound2.jpg, Layers in Schiaparelli Crater, as seen by HiRISE under HiWish program
46814 1785layeredmound3.jpg, Layered mound in Schiaparelli Crater, as seen by HiRISE under HiWish program
46814 1785layeresleft.jpg, Layers in Schiaparelli Crater, as seen by HiRISE under HiWish program
46814 1785layers2.jpg, Layers in Schiaparelli Crater, as seen by HiRISE under HiWish program
46814 1785layers3.jpg, Layers in Schiaparelli Crater, as seen by HiRISE under HiWish program
46814 1785layerscloseleftbottom.jpg, Close view of layers in Schiaparelli Crater, as seen by HiRISE under HiWish program Dark sand is visible on some layers.
ESP 046814 1785layersclosecolor.jpg, Close, color view of layers in Schiaparelli Crater, as seen by HiRISE under HiWish program Dark sand is visible on some layers.

File:ESP 054554 1785layers.jpg, Wide view of layers and rough terrain in Northwestern Schiaparelli Crater, as seen by HiRISE under HiWish program
File:54554 1785layersclose.jpg, Close view of layers and rough terrain in Northwestern Schiaparelli Crater, as seen by HiRISE under HiWish program
File:54554 1785layerspits.jpg, Close view of rough terrain and small pits in Northwestern Schiaparelli Crater, as seen by HiRISE under HiWish program
File:54554 1785strangepits.jpg, Close view of rough terrain in Northwestern Schiaparelli Crater, as seen by HiRISE under HiWish program
File:54554 1785strangeridges.jpg, Close view of rough terrain in Northwestern Schiaparelli Crater, as seen by HiRISE under HiWish program

Other Craters

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. 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 (Martian crater), Denning Crater shows a cluster of secondary craters.

Image:Flaugergues Crater Rim.JPG, Small crater with material flowing into it, on the rim of Flaugergues Crater, as seen by HiRISE.
Image:Dawes Crater.JPG, Dawes Crater floor with fresh impact craters, as seen by HiRISE. Click on image to see dark ejecta from some craters that formed when the impact reached a dark layer
Image:Dennin Crater Floor.JPG, Recent small crater on floor of Denning (Martian crater), Dennin Crater, as seen by HiRISE. Arrow shows group of secondary craters from ejecta falling down.

File:56716 1735secondries.jpg, Group of secondary craters, as seen by HiRISE under HiWish program

Wikibouguer.jpg, Bouguer (Martian crater) , as seen by CTX camera (on Mars Reconnaissance Orbiter).
Wikibakhuysen.jpg, Bakhuysen Crater, as seen by CTX camera (on Mars Reconnaissance Orbiter). Channels are visible on the north (top) and south (bottom) rims of crater.
Wikibakhuysenchannels.jpg, Channels on south rim of Bakhuysen Crater, as seen by CTX camera (on Mars Reconnaissance Orbiter). Note: this is an enlargement of the previous image of Bakhuysen Crater.
Wikilambert.jpg, Lambert Crater (Martian Crater), as seen by CTX camera (on Mars Reconnaissance Orbiter).

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. The peak is caused by a rebound of the crater floor following the impact. 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. 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.

White rock in Pollack crater

Within the region is Pollack (crater), 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'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.

Image:Whiterock.JPG, Whiterock on crater floor may be what's left of a much larger deposit. Arrow shows that the deposit once reached much farther. Picture taken by THEMIS.
Image:Pollack Crater White Rock.jpg, White Rock in Pollack Crater as seen by HiRISE.
Image:Close-up of Pollack Crater White Rock.JPG, Enlargement of White Rock in Pollack Crater, as seen by HiRISE.

Pollack crater's white rocks:
White rock in Pollack crater: Mariner 9 (1971-1972)White rock in Pollack crater: Viking (1976-1980)White rock in Pollack crater: Mars Global Surveyor (1997-2006)White rock in Pollack crater: 2001 Mars Odyssey (2001-present)White rock in Pollack crater: Mars Express (2004-present)White rock in Pollack crater: Mars Reconnaissance Orbiter (2006-present)

Channels in Sinus Sabaeus quadrangle

There is enormous evidence that water once flowed in river valleys on Mars. Images of curved channels have been seen in images from Mars spacecraft dating back to the early seventies with the Mariner 9 orbiter. 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.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

ESP 041974 1740channel.jpg, Winding channel, as seen by HiRISE under HiWish program
ESP 045813 1510channels.jpg, Channels, as seen by HiRISE under HiWish program

ESP 051192 1555channel.jpg, Channels, as seen by HiRISE under HiWish program

File:ESP 056585 1555channels.jpg, Channels, as seen by HiRISE under HiWish program

Ridges

File:ESP 057415 1740ridge.jpg, This straight ridge may be a dike that has been exposed by erosion. It was initially formed by magma moving under the surface along weak spots. The picture was taken with HiRISE under the HiWish program.

ESP 047368 1665ridge.jpg, This long, straight ridge may be a dike that has been exposed by erosion. It was initially formed by magma moving under the surface. The picture was taken with HiRISE under the HiWish program.

Other scenes from Sinus Sabaeus quadrangle

Image:Sinus Sabaeus map.JPG, Quadrangle map of Sinus Sabaeus labeled with major features. Colored rectangles represent image footprints of Mars Global Surveyor.
Image:Verde Vallis.JPG, Verde Vallis, as seen by THEMIS.

File:ESP 054976 1685dunes.jpg, Dunes, as seen with HiRISE under the HiWish program.

Other Mars quadrangles

Interactive Mars map

See also

* 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 (planetary geology), Vallis
* Water on Mars

References

Further reading

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

External links

{{DEFAULTSORT:Sinus Sabaeus Quadrangle
Sinus Sabaeus quadrangle,
Mars