The Sinus Sabaeus Region
MC-20
Topographical Map of Sinus Sabaeus Region
The Sinus Sabaeus Region covers the area from 315° to 360° west longitude and 0° to 30° degrees south latitude on Mars. Most of the region contains heavily cratered highlands. The northern part includes the huge Schiaparelli Crater.
Image of Sinus Sabaeus Region
Apparently this is one Region NASA has not explored in any great depth, maybe for some reason it is unimportant as there seems to be little video on it and the information available to the public is not that large. I will try to rectify the problem.
The dark regions of Mars are now being seen in greater detail than ever before by the Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC). As expected, none of these areas are covered by vegetation! But what has been a surprise is the great variety of dark surfaces seen. Before MGS, most had been thinking that these areas are sandy because all of the large Martian sand dunes are dark, too. But in many cases, dark dunes and sand are not found in the MOC images---such areas instead are thickly blanketed by a cracked, crusty covering of what may be fine silt instead of sand. The surfaces of the Sinus Sabaeus Region show dark, blanketed or mantled surfaces. This dark material in some places has bright dunes on top of it, and in other places appears to have narrow cracks running through it. If the dark material consisted of sand, it would show drifts and tails formed around and behind obstacles as are seen in the thick sand sheets of the Ganges Chasma. Because wind transports sand close to the ground, it interacts with obstacles such as the bright mounds to make drifts and tails.
As usual we begin this Phase by starting from the northeast corner of the Region. The first feature of note is Mädler Crater which is located at 3°E 11°S.
Mädler Crater
Mädler crater on Mars named is in honor of the German astronomer Johann Heinrich Mädler. The Crater is 125 km in diameter. On Earth, the longitude of the Royal Observatory in Greenwich, England, is defined as the 'prime meridian,' or zero degrees longitude. Locations on Earth are measured in degrees east or west from this position, but where is the equivalent position on Mars? Earth's prime meridian was defined by international agreement in 1884 as the position of the large 'transit circle', a telescope in the Royal Observatory's Meridian Building. The transit circle was built by Sir George Biddell Airy, the 7th Astronomer Royal, in 1850. For Mars, the prime meridian was first defined by the German astronomers W. Beer and J. H. Mädler in 1830-32. They used a small circular feature on the surface, which they called 'A’, as a reference point to determine the rotation period of the planet. 0 degrees on Mars begins with the Sinus Sabaeus Region and Mädler Crater is close to it. The Italian astronomer G. Schiaparelli used this feature as the zero point of longitude in his 1877 map of Mars. It was subsequently named Sinus Meridiani ('Middle Bay') by French astronomer Camille Flammarion. A crater in the Sinus Meridiani was later called Airy (half in that region and half in Sinus Sabaeus), named to commemorate the builder of the Greenwich transit. When the US Mariner 9 spacecraft mapped the planet at about 1 kilometer resolution in 1972, a more precise definition was needed. Merton Davies of the RAND Corporation was analyzing surface features and designated a 0.5-kilometer-wide crater, subsequently named 'Airy-0' (within the larger crater Airy) as the zero point. This crater was imaged once by Mariner 9 and once by the Viking 1 orbiter in 1978, and these two images were the basis of the Martian longitude system for the rest of the 20th century.
Location of the Prime Meridian and “Airy.”
To the east of Mädler Crater is the Evros Vallis located at 12°E 12°S.
Evros Vallis
It is 335 kilometers long and is named The Maritsa or Evros River which is the longest river that runs solely in the interior of the Balkans.
Leading directly into Mädler crater from the south is Marikh Vallis at 3°E 12°S.
Marikh Vallis
The Marikh Valles is 1280 kilometers long and is named for Word for "Mars" in Malaysian.
The Noachis Terra area covers the western half of the Sinus Sabaeus Region. Noachis Terra is one of the more extensive land masses (Terrae) on Mars, lying in the southern highlands roughly between the latitudes -20° and -80° and longitudes 30° west and 30° east so it covers the present area we are exploring.
Dunes in a Crater in Noachis Terra
Southeast of Mädler Crater at 11°E 18°S is Wislicenus Crater.
Wislicenus Crater
Wislicenus Crater: is an impact crater in the Sinus Sabaeus Region of Mars. It is about 139 km in diameter and was named after Walter Wislicenus, a German astronomer (1859–1905). Wislicenus 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.
Wislicenus Crater Floor, as seen by HiRISE. Erosion on floor has made layers visible.
To the southwest lies Newcomb Crater which we have already surveyed and to the southeast Bakhuysen Crater at 15.5°E 22.5°S.
Bakhuysen Crater
Large impact craters often have pits on their floors. Some of these (with raised rims) are later impacts, but some are thought to originate immediately after the crater forms when slurries of molten and broken rocks occupy the crater floor. Bakhuysen Crater, located in Noachis Terra, is thought to be the largest crater that possesses (and has preserved) these pitted materials. Bakhuysen Crater is 161 kilometers in diameter and is named after Hendricus Gerardus van de Sande Bakhuyzen (Apr 2, 1838, The Hague – Jan 8, 1923, Leiden) who was a Dutch astronomer.
Southeast of Bakhuysen Crater there is a wide canyon going from the south to the north. The western side is a scarp called Syclla Scopulus located at 19°E and 20°S.
Scylla Scopulus as seen by Themis
Scylla Scopulus is an irregular scarp located in the southern highlands of Mars. The arrows on the daytime IR image are pointing to the scarp where it crosses the image. Scylla Scopulus faces eastward, while Charybdis Scopulus [located to the east of Scylla] faces westward. Scopulus in Martian geology is a lobate of an irregular scarp. Scylla is named after the nymph Scylla that was turned into a 6-headed monster by the sorceress Circe in Homer’s Odyssey.
Charybdis Scopulus is located 19-21°E 18-28°S.
Location of Scylla Scopulus and Charybdis Scopulus as seen by Themis
Northeast of this area is Lambert Crater a medium sized crater at 26°E 20°S.
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Lambert Crater
Lambert crater is 92 kilometers in diameter. It is named after Johann Heinrich Lambert ( 26 August 1728 – 25 September 1777) who was a Swiss mathematician, physicist, philosopher and astronomer.
Just a short distance to the northeast of Lambert Crater is Bouguer Crater at 27.5°E 18.5°S.
Bouguer Crater
Bouguer Crater is an impact crater in the Sinus Sabaeus Region of Mars. It is 107 kilometers in diameter and was named after Pierre Bouguer, French physicist-hydrographer (1698-1758). When a comet or asteroid collides at a high rate of speed with the surface of Mars it creates an impact crater such as this one.
Layer and pitted outcrops in Bouguer Crater
To the northwest is the large Flaugergues Crater at 19°E 16.5°S.
Flaugergues Crater
Flaugergues Crater is a crater in the Sinus Sabaeus Region on Mars at 17°. It is about 245 km in diameter. It was named after Honore Flaugergues, a French astronomer (1755-1835).
Lineations in Eroded Material in Flaugergues Crater
Just to the northeast of Flaugergues Crater is the Mosa Vallis at 23°E 15°S.
Landforms in Mosa Vallis
Location of Mosa Vallis
The Mosa Vallis is 171 kilometers long and is named after the the Meuse River which is a major European river, rising in France and flowing through Belgium and the Netherlands before draining into the North Sea.
To the northeast of Mosa Vallis lies Pollack Crater at 25°E 7.5°S. It is well known for the exposed white rock surface exposed in the floor if the crater.
White Rock in Pollack Crater
Pollack Crater is an impact crater in the Sinus Sabaeus Region of Mars. It is 96.0 km in diameter and was named after James B. Pollack, an American physicist (1938–1994). Pollack Crater contains a large light toned deposit that was once thought to be a salt deposit. It is not really that light, the surrounding rocks are exceptionally dark and that makes this deposit appear white. Much of Earth's land surface is just a few hundred million years old. In contrast, 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. Scientists believe that it used to have a dynamic surface, but then volcanic activity ceased and the atmosphere was stripped away. The Mariner 9 spacecraft in the 1970s photographed a feature that was called "White Rock." 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 been eroded away.
The Brazos Valles is a group of channels that appear to outflow into the Schiaparelli Crater 4°S, 5.2°S, and two channels at 6°S between 16-20.5°E.
Brazos Valles (outflow channels numbered in red)
The Brazos Valles is 458 kilometers long before it breaks up into four channels, the main channel being #2. It was named after the Brazos River in Texas, which is the longest river in Texas.
The Brazos Valles enters the Schiaparelli Crater from the south and east. It is the largest crater in the entire Sinus Sabaeus Region centered at 17°E 2²S. Schiaparelli Crater is an impact crater on Mars named after Giovanni Schiaparelli (called the “Father of Mars“) located near the Mars equator. It is 461 kilometers (286 mi) in diameter. A crater within Schiaparelli shows many layers that may have formed by the wind, volcanoes, or deposition under water. Layers can be a few meters thick or tens of meters think.
Schiaparelli Crater MOLA Topographical Map
Recent research on these layers by scientists at California Institute of Technology (Caltech) suggest that ancient climate change on Mars caused by regular variation in the planet's tilt, may have caused the patterns in layers. On Earth, similar changes (astronomical forcing) of climate results in ice-age cycles.
Layers in a crater in the basin as seen by MGS.
The regular appearance of rock layers suggests that regular changes in climate may be the root cause. Regular changes in climate may be due to variations of a planet's tilt (called obliquity). The tilt of the Earth's axis changes by only a little more than 2 degrees since our moon is relatively large. In contrast Mars's tilt varies by tens of degrees. When the tilt is low (current situation on Mars), the poles are the coldest places on the planet, while the equator is the warmest (as on Earth). This could cause gases in the atmosphere, like water and carbon dioxide, to migrate pole-ward, where they'd freeze. When the obliquity is higher, the poles receive more sunlight, causing those materials to migrate away. When carbon dioxide moves from the Martian poles, the atmospheric pressure increases, maybe causing a difference in the ability of winds to transport and deposit sand. Also, with more water in the atmosphere sand grains may stick and cement together to form layers.
Layers in a crater in the basin of Schiaparelli Crater
Circular structures on floor of Schiaparelli Crater, as seen by HiRISE.
The Terra Sabaea Area covers the eastern half of the Sinus Sabaeus Region roughly from 20°E to 45°E.
Terra Sabaea Area eastern Sinus Sabaeus Region
The first area of importance we come to in this regions is the Verde Vallis which is an outflow channel at 30°E right on the northern border on the equator (0 degrees).
Verde Valles
The Verde Valles is 95 kilometers long and is named after The Verde River which is a major tributary of the Salt River in the U.S. state of Arizona.
Southeast of there at a considerable distance is Dawes Crater at 38°E 9°S.
Dawes Crater
Dawes Crater: is located in the Sinus Sabeaus Region of Mars. It is about 191 km (119 mi) in diameter, and was named after William R. Dawes, a British astronomer (1799–1868) who was ahead of his time in believing that Mars only had a thin atmosphere. Dawes presumed that the atmosphere of Mars was thin because surface markings on the planet could easily be seen.
Dawes Crater floor with fresh impact craters. Note that dark ejecta appeared from some craters that formed when the impact reached a dark layer.
To the southwest of Dawes crater is Denning Crater located at 33°E 18°S.
Denning Crater
Denning Crater is a crater in the Sinus Sabaeus Region of Mars . It is about 165 km in diameter and was named after William F. Denning, a British astronomer (1848–1931). It has secondary craters.
Recent small crater on floor of Denning Crater, as seen by HiRISE. Arrow shows group of secondary craters from ejecta falling down.
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