Small Pale Red Planet Issue 3 Phase 5

 

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.

 

.White Rock in Pollack Crater

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.

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 above of Denning Crater shows a cluster of secondary craters.

Small Pale Red Planet Issue 3 Phase 4.2

 

Margaritifer Sinus Region

MC-19

 

Topographical Map of the Margaritifer Sinus Region with the location of the MER Opportunity Landing Site.

In part two of this Phase we start in the center of the Margaritifer Sinus Region in an area called the Margaritifer Terra Area.

Margaritifer Terra and Vicinity

At 240°E 21°S we come to Jones Crater.

Geologic Contacts in Jones Crater

Jones Crater is 94 km in diameter and is named after Sir Harold Spencer Jones KBE (29 March 1890 Kensington, London – 3 November 1960) who was an English astronomer.

Just to the east of Jones Crater is the Loire Valles at 18.11°S 343.3°E.

The Loire Valles

The Loire Valles is 720 km in length and is is named after the Loire River the longest river in France.

The outflow channel leading north from the Ladon Basin is the Morava Valles.  It is located at 335°E 14°S.

Near the Mouth of Morava Valles

The Morava Valles is 325 km long and is named after the Morava (German: March, Hungarian: Morva) river in Central Europe.  The Morava Valles leads to the Margaritifer Chaos.  Morava Valles is an outflow channel for the Ladon Basin and discharged water towards the large regions of chaotic terrain near the head of Ares Valles.  Because the valley emerges full bore from Ladon Basin (much like the Niagara river emerges from Lake Erie on the Earth), it has been hypothesized that it was formed when a lake overflowed the basin.  There are numerous valleys, including the large Ladon Valles, that end along the margin of Ladon Basin. Some of the outcrops visible in this image and elsewhere in the basin show evidence of layering due to deposition of sediments.

Margaritifer Chaos Area

Layer Bedrock in Margaritifer Chaos

The formation of the large outflow channels on Mars have been attributed to catastrophic discharges of ground water. Many of the channels start in areas where the ground has apparently collapsed: the surface is now well below the surrounding undisturbed ground. Within the collapsed region, blocks of undisturbed material can often be seen and this has led to such regions being called chaotic terrain.

The area referred to as Aureum Chaos is located at 333 degrees East, 4.5 degrees South on the West side of the Margaritifer Chaos.

The Aureum Chaos

The Aureum Chaos is a rough, collapsed region in the Margaritifer Sinus Region (MC-19) portion of the planet Mars at approximately 4.5° south latitude and 333° East longitude. Located on the west side of the Margaritifer Chaos.  It is 368 km across and was named after a classical albedo feature name. The classic name came from one of the first maps of Mars drawn by Schiaparelli who has been called the "Father of Mars." He called the feature "Aurea Cherso, which translates to the golden peninsula—an ancient name for Malaya.  Aureum is the Latin word for gold. In chemistry, the symbol for gold is Au from gold's Latin name. In many places, the canyons of Aureum Chaos are about 1 km deep—a little more than half the depth of the Grand Canyon. But, Aureum Chaos covers an area about the size of the state of Alabama, almost 20 times larger than the Grand Canyon National Park.  Some take places like this on Mars to be Martian underground cities.  But this is not the case.  The features that appear to rise between the blocks are actually channels running between the blocks.  So this is a natural phenomena caused by the action of water draining out of the area. There still may be some water(ice) inside the blocks themselves.

Colorful Aureum Chaos

Following another channel leading to the northeast from Margaritifer Chaos we come to Ini Chaos which is centered at 2°S 343 E.

Proposed Landing Area in Iani Chaos, as seen by Themis

Iani Chaos is a minor canyon accounting for a portion of the extraterrestrial valley, Ares Vallis, of the Margaritifer Sinus Region  of the planet Mars. This is the source region of Ares Vallis on Mars, where it is centered at approximately ~342°E, 2°S. The chaotic terrain is widely believed to have formed via the removal of subsurface water or ice, resulting in flooding at the surface, and the formation of Ares Vallis. Within Iani Chaos, deposited stratigraphically above the chaotic terrain, are smooth, low-slope, intermediate-to-light-toned deposits that are rich in a hydrated mineral that is most likely gypsum as well as hematite.  Those two minerals are usually formed in connection with water.

In the northeastern corner of the Margaritifer Sinus Region we come to the Meridiani Planum which is part of the larger area of Arabia Terra that extends into the surrounding Regions as well.

Meridiani Planum

Meridiani Planum is a plain located 2 degrees south of Mars' equator (centered at  0.2°N 357.5°E), in the westernmost portion of Terra Meridiani. It hosts a rare occurrence of gray crystalline hematite. On Earth, hematite is often formed in hot springs or in standing pools of water; therefore, many scientists believe that the hematite at Meridiani Planum may be indicative of ancient hot springs or that the environment contained liquid water. The hematite is part of a layered sedimentary rock formation about 200 to 800 meters thick. Other features of Meridiani Planum include volcanic basalt and impact craters. Results from the Opportunity Rover indicate that its landing site was once saturated for a long period of time with liquid water, possibly of high salinity and acidity. Features that suggest this include cross-bedded sediments, the presence of many small spherical pebbles that appear to be concretions, vugs inside rocks, and the presence of large amounts of magnesium sulfate and other sulfate-rich minerals such as Jarosite.

The Landing of the Mars Rover Opportunity

The Rover landed in an impact crater which became known as Eagle Crater

Eagle Crater Rim

This high-resolution image captured by the Mars Exploration Rover Opportunity's panoramic camera highlights the puzzling rock outcropping that scientists were eagerly planning to investigate. At that time, Opportunity was on its lander facing northeast; the outcropping lies to the northwest. These layered rocks measure only 10 centimeters (4 inches) tall and were thought to be either volcanic ash deposits or sediments carried by water or wind. Data from the panoramic camera's near-infrared, blue and green filters were combined to create this approximate, true-color image. The interior of a crater surrounding the Mars Exploration Rover Opportunity at Meridiani Planum on Mars can be seen in this color image from the rover's panoramic camera. This is the darkest landing site ever visited by a spacecraft on Mars. The rim of the crater is approximately 10 meters (32 feet) from the rover. The crater is estimated to be 20 meters (65 feet) in diameter. Scientists are intrigued by the abundance of rock outcrops dispersed throughout the crater, as well as the crater's soil, which appears to be a mixture of coarse gray grains and fine reddish grains.

 

The rock "Berry Bowl".

 

Martian blueberries (hematite spheres)  near Opportunity’s landing site.

 

Drawing showing how "blueberries" came to cover much of surface in Meridiani Planum.

Microscopic images of the soil taken by Opportunity revealed small spherically shaped granules. They were first seen on pictures taken on Sol 10, right after the rover drove from the lander onto Martian soil.   On March 18 the results of the investigation of the area called "Berry Bowl" was announced. This site is a large rock with a small, bowl-shaped depression, in which a large number of spherules had accumulated. The MIMOS II Mössbauer spectrometer was used to analyze the depression and then the area of the rock right beside it. Any difference in the measured data was then attributed to the material in the spherules. A large difference in the obtained "spectra" was found. "This is the fingerprint of hematite, so they concluded that the major iron-bearing mineral in the berries was hematite," said Daniel Rodionov, a rover science team collaborator from the University of Mainz, Germany. This discovery seems to strengthen the conclusion, that spherules are concretions, grown in wet condition with dissolved iron.

Some of Mars as Seen by the Mars Opportunity Rover

Bedrock Minerals: Few rocks were visible on the surface where Opportunity landed, but bedrock that was exposed in craters was examined by the suit of instruments on the Rover. Bedrock rocks were found to be sedimentary rocks with a high concentration of sulfur in the form of calcium and magnesium sulfates. Some of the sulfates that may be present in bedrocks are kieserite, sulfate anhydrate, bassanite, hexahydrite, epsomite, and gypsum. Salts, such as halite, bischofite, antarcticite, bloedite, vanthoffite, or gluberite may also be present.

Opportunity Rover at Endeavor Crater

Endeavor Crater is located at 354.9°E 2.5°S.  When Opportunity Rover traveled to the rim of Endeavour crater, it soon found a white vein that was later identified as being pure gypsum. It was formed when water carrying gypsum in solution deposited the mineral in a crack in the rock.

Endeavor Crater Western Rim  HiRISE DTM

This digital terrain model covers the western rim of Endeavour Crater where the Mars Exploration Rover Opportunity has been investigating since 2011. It provides valuable topographic data that have been very useful in Opportunity mission planning.

Sub image of region of Exploration

For example, this sub image shows a northward perspective view of HiRISE and compositional data from the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) overlaid over the DTM of Endeavour Crater. This image shows where orbital data indicate possible clay (red), sulfate (green), and volcanic (blue) minerals are located, where the former two attest to the regions aqueous ancient past. Ongoing surface operations by Opportunity are attempting to reveal the geologic history at Endeavour crater.

“Heat Shield Rock” was the first meteorite ever identified on another planet, discovered by Opportunity

Opportunity Rover found meteorites just sitting on the plains. The first one analyzed with Opportunity’s instruments was called "Heat shield Rock," as it was found near where Opportunity’s heat shield landed. Examination with the Miniature Thermal Emission Spectrometer (Mini-TES), Mossbauer spectrometer, and APXS lead researchers to, classify it as an IAB meteorite. The APXS determined it was composed of 93% iron and 7% nickel.

The Mars Opportunity Rover remains active as of 2014, having already exceeded its planned 90 sol (Martian days) duration of activity by 9 years, 267 days (in Earth time). Opportunity has continued to move, gather scientific observations, and report back to Earth for over 40 times its designed lifespan.  Mission highlights include the initial 90 sol mission, finding extra-Martian meteorites such as in the Meridiani Planum, and over two years studying Victoria crater. It survived dust-storms and reached Endeavour crater in 2011, which has been described as a "second landing site".  As of January 7, 2014 the total odometry for the Mars Opportunity Rover is 24.07 miles (38.73 kilometers).  It holds the distance record for the longest distance traveled on any planet thus far by a planetary rover.

Meridiani Planum is part of a larger area called Arabia Terra which covers the northeast corner of the Margaritifer Sinus Region.

Possible Rover Landing Site - Southwest Arabia Terra   HiRISE DTM  at 5.6°S 355°E.

Arabia Terra is a large upland region in the north of Mars in that lies mostly in the Arabia Region. It is densely cratered and heavily eroded. This battered topography indicates great age, and Arabia Terra is presumed to be one of the oldest terrains on the planet. It covers as much as 4,500 km (2,800 mi) at its longest extent.

Possible Cyclic Bedding in A Crater in Arabia Terra

Miyamoto Crater

Miyamoto Crater is located in southwest Meridiani Planum (and southwest of the Mars Exploration Rover Opportunity landing site). This image shows fairly smooth plains and some areas covered by wind streaks, suggesting that wind is an active process here, depositing surface material downwind in the form of streaks.  This landing site is adjacent to the hematite-bearing plains unit where the Opportunity rover sits. The CRISM instrument has detected phyllosilicates (clay minerals) at this landing site, which scientists believe to have formed in the presence of water. The MSL rover would be able investigate the mineral diversity here, which includes phyllosilicates and sulfates. Of course the MSL landed somewhere else and this investigation has not happened yet.  Miyamoto Crater is located at 2.8°S 353°E.  It is 160 km in diameter.

The next feature we come to is Beer Crater located at 15°S 351.5°E.

The Floor of Beer Crater

This crater was named after German astronomer Wilhelm Beer. It is an ancient crater which is 90  kilometers diameter, located south of Meridiani Planum.  The full-resolution color sample above shows fractured bedrock with dark sand filling low areas. The circular rocky features are probably eroded impact craters and the thin linear features are windblown deposits.  The Aeolian (wind) erosion and modification of this ancient surface make it difficult to deduce how the rocks were initially emplaced, but the channeled rims suggest that these could be alluvial fans: deposits carried by flowing water.

Going further south we come to Peta Crater.  It is located at  21°S 351° E.

Peta Crater as seen by Themis

Peta Crater is 80.5 km in diameter and is named after a Greece place name.  Analysis of this image reveal characteristics, such as layers along the ridge walls in the center of the crater that would indicate that the ridge was deposited by flowing water. Rocks and boulders might be found eroding from the ridge, their size and shape offering clues to the strength of the ridge material.

Just to the southwest of Peta Crater is the Parana Valles at 23°S 350°E.

Parana Valles

Parana Valles is a valley in the Margaritifer Sinus Region  of Mars.   It is 350 km long and was named after an ancient and modern name for a South American river (Brazil & Argentina). The low area between Parana Valles and Loire Vallis is believed to have once held a lake.

CTX context image for this image that was taken with HiRISE.

Note long ridge going across the image is probably an old stream. The box indicates the area for HiRISE image.

To the west of Parana Valles is Erythraeum Chaos at 22°S 347.5°E.

Erythaeum Chaos As seen by Themis

Erythraeum Chaos  is 149 km in diameter and is further proof that this area contained a great deal of water.

To the southeast of Erythraeum Chaos is Novara Crater at 25°S and 249°E.

Possible Phyllosilicate on Floor of Novara Crater

Novara Crater is 87 miles in diameter and is named after and Italy place name.

On the eastern border of the Margaritifer Sinus Region between 22-26.5°S  is the western half of Newcomb Crater.

Newcomb Crater

Newcomb Crater is 252 km in diameter and is named after Simon Newcomb (March 12, 1835 – July 11, 1909) who was a Canadian-American astronomer and mathematician.