Small Pale Red Planet Issue 2 Phase 7

 

Syrtis Major Region

MC-13

The Region covers longitudes 270° to 315° west and latitudes 0° to 30° north on Mars.  Syrtis Major is an old shield volcano with a central depression that is elongated in a north-south direction. It contains the calderas Meroe Patera and Nili Patera.

 

Topographical Map of the Syrtis Major Region

The name Syrtis Major is derived from the classical Roman name Syrtis Major for the Gulf of Sidra on the coast of Libya (classical Cyrenaica).  Syrtis Major was the first documented surface feature of another planet. It was discovered by Christian Huygens, who included it in a drawing of Mars in 1659.

Image of the Syrtis Major Region

The central part of the Region is dominated by dark dust and lava flows of the Syrtis Major Planum region. These lava flows are partly bounded to the east by a large depression, Isidis basin, which contains smooth plains, and to the west and north by heavily cratered and moderately faulted highlands. Latitude range 0 to 30 degrees, longitude range -90 to -45 degrees.

Syrtis Major is of great interest to geologists because several types of igneous rocks have been found there with orbiting spacecraft. Besides basalt, dacite and granite have been found there. Dacite originates under volcanoes in magma chambers. Dacites form at the top of the chamber, after heavy minerals (olivine and pyroxene) containing iron and magnesium have settled to the bottom. Granite is formed by an even more complex process.  Some areas of Syrtis Major contain large amounts of the mineral olivine. Olivine turns into other minerals very rapidly in the presence of water, so a high abundance of olivine suggests that for a long time little water has been there.

Starting from the Northeast corner of the Region we head south and encounter the Flammarion Crater at  25 N and 48 E. 

Layers in Flammarion Crater.

The crater was named after Nicolas Camille Flammarion (26 February 1842 – 3 June 1925) a French astronomer and author.  The crater is 173 km in diameter.

Passing Flammarion Crater we head south into the uplands of the Terra Sabaea.  The next Crater we come to is Schöner Crater.

Schöner Crater is located at  20.1°N 309.5°W.  It is 195 km in diameter and named after           Johannus Schöner (January 16, 1477 in – January 16, 1547). He was a priest, astronomer, astrologer, geographer, cosmographer, cartographer, mathematician, globe and scientific instrument maker.

Continuing south we next come to Cusus Valles.

Rocky layers around Cusus Valles

As we travel further southward the elevation increases and southeast of the Cusus Valles we come to Leighton Crater which is closer to the equator.

Possible Carbonate-Rich Terrain in Central Structure of Leighton Crater

Leighton Crater is located at 3.06°N 302.32°W and is 69 km in diameter so it is a smaller crater than the ones we have been coming across.  The crater was named after Robert B. Leighton (September 10, 1919 – March 9, 1997) who was a prominent American experimental physicist.  Research published in October 2010, described a large deposit of carbonate rocks found inside Leighton Crater at a level that was once buried 4 miles (6 km) below the surface. Finding carbonates in an underground location strongly suggests that Mars was warmer and had more atmospheric carbon dioxide and ancient seas. Because the carbonates were near silicate minerals and clays hydrothermal systems like the deep-sea vents on Earth may have been present.

Going north from there we go along the border of Terra Sabaea and Syrtis Major Planum (or Plains).  There are not many named craters in the area until we come to the huge Antoniadi Crater located at  21.5 degrees north latitude and 61.1 degrees east longitude.

Antoniadi Crater with Inverted Branching Stream Channels

Antoniadi Crater is 394 km in diameter and was named after Eugène Michel Antoniadi (Greek: Εὐγένιος Μιχαὴλ Αντωνιάδης; 1 March 1870,  – 10 February 1944, ) who was a Greek astronomer.

Exploring Antoniadi Crater

Probably connected to the northern rim of Antoniadi Crater is the Anquakuh Vallis.

Auquakuh Vallis in Syrtis Major. Location is 28.2 degrees north latitude and 299.2 degrees west longitude.

Anquakuh Vallis is an ancient river valley in the Syrtis Major Region on Mars.  It is 312 km long, and was named for the word for 'Mars' in Quechua (Inca).  At one time a dark layer covered the whole area, now only a few pieces remain as buttes.  Many places on Mars have buttes that are similar to buttes on Earth, such as the famous ones in Monument Valley, Utah. Buttes are formed when most of a layer(s) of rocks are removed from an area. Buttes usually have a hard, erosion-resistant cap rock on the top. The cap rock causes the top of a butte to be flat.

Further to the East but coming from the north also is the Huo Hsing Vallis.

Dikes in Huo Hsing Vallis in which liquid rock once flowed.

Huo Hsing Vallis is an ancient river valley in the Syrtis Major Region of Mars at 30.5° north latitude and 293.4° west longitude. It is about 318 km long and was named after the word for "Mars" in Chinese. Some crater floors in the Syrtis Major area show elongated ridges in a lattice-like pattern. Such patterns are typical of faults and breccia dikes formed as a result of an impact. The ridges are found where there has been enhanced erosion. Pictures on this page show examples of these dikes. Water may flow along faults. The water often carries minerals that serve to cement rock materials thus making them harder. Later when the whole area undergoes erosion the dikes will remain as ridges because they are more resistant to erosion. This discovery may be of great importance for future colonization of Mars because these types of faults and breccia dikes on earth are associated with key mineral resources. Perhaps, when people live on Mars these areas will be mined as they are on earth.

Similar Dikes located on Earth in Colorado

Dikes or narrow ridges occur in some places on Mars. They may be formed by different means, but some are probably caused by molten rock moving underground, cooling into hard rock, then being exposed by the erosion of softer, surrounding materials. Such a feature is termed a dike. The discovery on Mars of dikes that were formed from molten rock is highly significant because dikes indicate the existence of intrusive igneous activity. On the Earth such activity is associated with precious metals like gold, silver, and tellurium.  Mapping the presence of dikes allows us to understand how magma (molten rock under the ground) travels and where it could have interacted with surrounding rock, thus producing valuable ores. Deposits of important minerals are also made by dikes and other igneous intrusions heating water which then dissolves minerals that are deposited in cracks in nearby rock. One would expect a great deal of intrusive igneous activity to occur on Mars because it is believed there is more igneous activity under the ground than on top, and Mars has many huge volcanoes.

Huo Hsing Vallis Ridges, as seen by HiRISE. Ridges may be caused by water moving along faults.

Going south from there we come to Baldet Crater.

Megabreccia on Floor of Baldet Crater

Baldet Crater is located at 23.0°N 294.6°W and is 180 km in diameter.  It was named after Ferdinand Baldet (16 March 1885 – 8 November 1964) who was a French astronomer.

To the southeast in the Syrtis Major Planum we come to Toro Crater located at 17°N and 71.7°E.  It is a small crater about 40 km in diameter.

Exploring the floor of Toro Crater

Toro Crater may have experienced hydrothermal alteration, producing diverse minerals. The mineral diversity leads to diverse color in HiRISE, especially when enhanced as in this sub image. In general the blue and green colors indicate unaltered minerals like pyroxene and olivine, whereas the warmer colors indicate alteration into clays and other minerals. The linear north-south trending features are windblown dunes that are much younger than the bedrock.

To the southwest of Toro Crater is  Arnus Vallis.

Layers in Arnus Vallis

Sand dunes are found all over Mars. Often sand dunes will form in low areas, for example on the floor of ancient river valleys.   Dunes on the floor of Arnus Vallis, an old river valley are visible in a picture above. Dunes in valleys on Mars usually lie at right angles to the valley walls.  Arnus Vallis is an ancient river valley in the Syrtis Major Region of Mars, located at 14.1° north latitude and 289.5° west longitude. It is 280 km long and was named after the classical and present day Arno River in Tuscany, Italy (previously named Arena Rupes).

In an elongated valley- like area to the southwest of Arnus Vallis are the two volcanoes of the Region located at an elevation at 0-1000 meters.  The surrounding terrain is between 1000-3000 meters high. Here we are still in the Syrtis Major Planum.  The two volcanoes are the Nili Patera and Meroe Patera mentioned earlier.

THEMIS daytime infrared image mosaic showing the central portion of the broad, low-lying shield volcanoes in the Syrtis Major Planum, just north of the equator in the eastern hemisphere of Mars. The calderas Nili Patera and Meroe Patera are visible to the upper left and lower right of center, respectively.

Here there is  a 350 by 150 km north-south elongated central depression containing the calderas Nili Patera and Meroe Patera, which are about 2 km deep. The floors of the calderas are not elevated relative to the terrain of the surrounding Syrtis Major Planum. The floor of Nili Patera is the less cratered, and therefore the younger, of the two. While most of the rock is basaltic, dacite has also been detected in Nili Patera. Satellite gravity field measurements show a positive gravity anomaly centered on the caldera complex, suggesting the presence of a 600x300 km north-south elongated extinct magma chamber below, containing dense minerals (probably mainly pyroxene, with olivine also possible) that precipitated out of magma before eruptions. Crater counts date the Syrtis Major Region to the early Hesperian epoch; it postdates formation of the adjacent Isidis impact basin.

Going southeast from the volcanoes on a 45 degree angle we come to the Libya Montes in the southeast corner of the Syrtis Major Region on the Equator.  The Libya Montes are a highland terrain on Mars up-lifted by the giant impact that created the Isidis basin to the north.  During 1999, this region became one of the top two that were being considered for the canceled Mars Surveyor 2001 Lander. The Isidis basin is very ancient. Thus, the Libya Montes that form the southern Isidis basin rim contain some of the oldest rocks available at the Martian surface, and a landing in this region might potentially provide information about conditions on early Mars.  It’s Coordinates are 1.44°N 88.23°E.

The Libya Montes

After they were formed by the Isidis impact, (estimated to have occurred between 3.7-3.1 billion years ago) the Libya Montes were subsequently modified by a large variety of processes, including fluvial activity, wind erosion and impact cratering. In particular, precipitation induced surface runoff and groundwater seepage resulted in the formation of fluvial landforms, i.e., dense valley networks, broad and elongated valleys, delta deposits, alluvial fans, open-basin paleo lakes and coastlines.

As you enter the Libya Montes from the west you come across the Zarqa Valles.

The Zarqa Valles is located at 0.16°N 80.82°E.  It is 490 km long and is named after the Zarqa River (Arabic: نهر الزرقاء‎, Hebrew: נחל יבוק, Yabok river)  the second largest tributary of the lower Jordan River.

The Libya Montes is also known to have the second face on Mars,  that I have mentioned earlier. The Libya Montes has a face-like formation that appears even when viewed at different angles and with different sun angles. It can be found in the Mars Global Surveyor, MOC narrow-angle image M02-03051. Also in HiRISE image ESP 018368 1830 (non-map projected) and ESP 018223 1830—a stereo pair that allows 3D terrain data to be generated. Like the  the first Face on Mars, it is an example of pareidolia.  That is the imagined perception of a pattern where it does not actually exist, as in considering Mars to have human features.

Sometimes called "The Crowned Face"

The Isidis Planitia is a plain located inside a giant impact basin on Mars, centered at  12.9°N 87.0°E. It covers a little over a quarter of the Eastern part of the Syrtis Major Region. It is the third biggest obvious impact structure on the planet after the Hellas and Argyre basins – it is about 1,500 km (930 mi) in diameter. Due to dust coverage, it typically appears bright in telescopic views, and was mapped as a classical albedo feature, the Isidis area was visible by telescope in the pre-spacecraft era.

Topographical Map of the Isidis Basin

Very Recent Small Crater in Isidis Planitia

Around the Isidis basin magnesium carbonate was found by MRO. This mineral indicates that water was present and that it was not acidic, pH conditions more favorable for the evolution of life.  The name "Isidis Planitia" follows the earlier name Isidis Region ("Isis' Region"). Isis is the Egyptian goddess of heaven and fertility.

Jezero Crater is located on the western edge of the Isidis Planitia. Once flooded with water, the crater contains a fan-delta deposit rich in clays.  In several Slavic languages including Bosnian, Croatian, Czech, Serbian, and Slovenian, the word Jezero means "lake".  Its location is 18.4°N 282.4°W and it is 49 km in diameter.

Proposed MSL Landing Site in Jezero Crater

Layered Valley Connected to the Eastern Part of Jezero Crater

Nili Fossae is a group of large, concentric grabens  that have been eroded and partly filled in by sediments and clay-rich ejecta from a nearby giant impact crater, the Isidis basin.  It is located at approximately 22°N, 75°E, and has an elevation of −0.6 km (−0.37 mi). Nili Fossae was on the list of potential landing sites of the Mars Science Laboratory, arriving in 2012, but was dropped before the final four sites were determined. A large exposure of olivine is located in Nili Fossae. In December 2008, NASA's Mars Reconnaissance Orbiter found that rocks at Nili Fossae contain carbonate minerals, a geologically significant discovery. Other minerals found by MRO are aluminum smectite, iron/magnesium smectite, hydrated silica, kaolinite group minerals, and iron oxides.  NASA scientists discovered that Nili Fossae is the source of plumes of methane raising- the question is whether this source originates from biological sources. Researchers in July 2010 suggested that carbonate bearing rocks found in the Nili Fossae region of Mars are made up of hydro thermally altered ultramafic rocks. Consequently, hydrothermal activity would have provided sufficient energy for biological activity. Evidence of living organisms could have been preserved. Possible evidence of 'buried life' was recently found at Nili Fossae.

Nili Fossae as seen by CRISM. Top left: location of observation. Bottom left: context of observation. Top right: yellow-brown areas denote olivine, bright green areas denote phyllosilicates and purple areas pyroxene. Bottom right: approximate true-color view of the target area.

The coordinates for Nili Fossae are 22.57°N 76.8°E and it covers an area 667 km. CRISM is the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) is a visible-infrared spectrometer aboard the Mars Reconnaissance Orbiter searching for mineralogical indications of past and present water on Mars.  CRISM is being used to identify locations on Mars that may have hosted water, a chemical considered important in the search for past or present extraterrestrial life. In order to do this, CRISM is mapping the presence of minerals and chemicals that may indicate past interaction with water - low-temperature or hydrothermal. These materials include iron and oxides, which can be chemically altered by water, and phyllosilicates and carbonates, which form in the presence of water. All of these materials have characteristic patterns in their visible-infrared energy and are readily seen by CRISM. In addition, CRISM is monitoring ice and dust particulates in the Martian atmosphere to learn more about its climate and seasons.

The CRISM Instrument

Exploring the Nili Fossae Area

In the Southern part of Nili Fossae we come to Hargraves Crater.

Hargraves Crater in Southern Nili Fossae

It is located at 20.76°N 284.36°W and  is 68 km in diameter.  It was named after Robert B. Hargraves (August 11, 1928 – March 21, 2003) who was an American geologist who worked as a professor at Princeton University.

Going to the northeast of Nili Fossae we come to the Arena Colles area.

Arena Colles Phyllosilicate Deposit

The Arena Colles is composed of a group of hills and knobs.  It is my theory that wherever there is a large Phyllosilicate or clay deposit there is a good possibility that through chemical reactions with local bacteria methane gas can be produced. and that  may be the case here.  The bacteria could be an undiscovered variety that would be producing the gas.   The Arena Colles area is located at 24°N and 81°E.

Located in the center of the Arena Colles area is Peridier Crater.

Linear Ridges and Fans on Floor of Peridier Crater

Peridier Crater is located at 25.7°N 276.2°W it is 100 km in diameter.  It was named after Julien Péridier (1882 – April 19, 1967) a French electrical engineer and amateur astronomer.

Small Pale Red Planet Issue 2 Phase 6

 

Arabia Region

MC-12

 

Topographical Map of the Arabia Region

This Region contains part of the classic area of Mars known as Arabia. It lies on the boundary between the young northern plains and the old southern highlands. The Arabia Region covers the area from 315° to 360° west longitude and 0° to 30° north latitude.

Image of the Arabia Region

The surface of the Arabia Region appears to be very old because it has a high density of craters, but it is not near as high in elevation as typical old surfaces. On Mars the oldest areas contain the most craters; the oldest period is called the Noachian after the Region Noachis. The Arabia Region contains many buttes and ridges.

Layered butte in Arabia Terra, as seen by HiRISE under HI Wish program. Location is 29.7 N and 6.4 E.

Some believe that during certain climate changes an ice-dust layer was deposited; later, parts were eroded to form buttes. Some outflow channels are found in Arabia, namely Naktong Vallis, Locras Valles, Indus Vallis, Scamander Vallis, and Cusus Valles.  The Arabia Region has many unnamed craters and a very high crater population some of them are very large.

Layers in Arabia Terra  as seen by HiRISE under HI Wish program

Starting from the northeast corner of the Region we enter into  the Arabia Terra area which covers about a third of the Arabia Region-especially in the western part.  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, centered roughly at  19.79°N 30°E with its eastern and southern regions rising 4 km (13,000 ft) above the north-west. Alongside its many craters, canyons wind through the Arabia Terra, many emptying into the large northern lowlands of the planet, which borders Arabia Terra to the north.

 

Northern Arabia Terra

The first crater of any consequence that we come to is Maggini Crater.  It is located at 28.0°N 350.6°W and is 143 km in diameter.

.Maggini Crater

Mentore Maggini (February 6, 1890 – May 8, 1941) was an Italian astronomer.  He was director of the Collurania Observatory and is best known for his maps of Mars and the work on binary stars. This crater on Mars was named in his honor.

Going further south  we come to Gill Crater.

Layers in Gill Crater wall, as seen by HiRISE under HI Wish program. Location is 16.5 N and 5.4 E.

Layers in mesa, as seen by HiRISE under HI Wish program also in Gill Crater.

Meridiani Planum in Southwest Arabia Region corner on the Equator

It is believed a source of Martian Methane comes from this region.    One study with the Planetary Fourier Spectrometer in the Mars Express spacecraft found possible methane in three areas of Mars, one of which was in the Arabia Region. One possible source of methane is from the metabolism of living bacteria. However, a recent study indicates that to match the observations of methane, there must be something that quickly destroys the gas, otherwise it would be spread all through the atmosphere instead of being concentrated in just a few locations.  Its destruction would be caused by the sun’s radiation and cosmic rays. There may be something in the soil that oxidizes the gas before it has a chance to spread which seems doubtful   Life forms could  be producing this gas as a by- product of their metabolism under the ground.

Martian Methane Production

Trace amounts of methane in the atmosphere of Mars were discovered in 2003 and verified in 2004. As methane is an unstable gas, its presence indicates that there must be an active source on the planet in order to keep such levels in the atmosphere. It is estimated that Mars must produce 270 tons of methane a year, but asteroid impacts are believed to account for only 0.8% of the total methane production. Although geologic sources of methane such as serpentinization are possible, the lack of current volcanism, hydrothermal activity or hotspots are not favorable for this form of geologic methane. It has been suggested that the methane was produced by chemical reactions in meteorites, driven by the intense heat during entry through the atmosphere. Although research published in December 2009 ruled out this possibility,  research published in 2012 suggest that a source may be organic compounds on meteorites that are converted to methane by ultraviolet radiation.  The existence of life in the form of microorganisms such as methanogens is among the possible, but as yet unproven sources. If microscopic Martian life is producing the methane, it likely resides far below the surface, where it is still warm enough for liquid water to exist.  Since the 2003 discovery of methane in the atmosphere, some scientists have been designing models and in vitro experiments testing growth of methanogenic bacteria on simulated Martian soil, where all four methanogen strains tested produced substantial levels of methane, even in the presence of 1.0wt% perchlorate salt. The results reported indicate that the perchlorates discovered by the Phoenix Lander would not rule out the possible presence of methanogens on Mars.  In June 2012, scientists reported that measuring the ratio of hydrogen and methane levels on Mars may help determine the likelihood of life on Mars. According to the scientists, "...low H2/CH4 ratios (less than approximately 40) indicate that life is likely present and active." Other scientists have recently reported methods of detecting hydrogen and methane in other extraterrestrial atmospheres as well.

Next we head to the northeast to Capen Crater.  The Mars Reconnaissance Orbiter showed deformation bands in Capen Crater, located in the Arabia Region. Deformation bands are small faults with very small displacements. They often proceed large faults. They develop in porous rocks, like sandstone. They can restrict and/or change the flow of fluids like water and oil. The bands on Mars are a few meters wide and up to a few kilometers long. They are caused by the compression or stretching of underground layers. Erosion of overlying layers make them visible at the surface. Capen Crater was unnamed before the discovery of deformation bands. It was named for Charles Capen, who studied Mars at JPL's Table Mountain Observatory in California and at Lowell Observatory in Arizona.

The group of lines running up and down in the image are believed to be deformation bands. They can be thought of as small faults.

Capen Crater is located at 6.57°N 345.73°W. and  it is 70 km in diameter. A large basin, maybe from an impact, was produced early in Martian history. It was so early that Mars still had a magnetic field generated by movements in a liquid core. The present day Arabia Region possesses a remnant magnetism from that ancient era.  Therefore it might be possible for atmospheric gases to exist in a higher concentration in this area in a elongated bubble due to this remnant of magnetism in this area.

Going to the northeast we come to Henry Crater.  Henry Crater is a large crater in the Arabia quadrangle of Mars, located at 10.9° north latitude and 336.7° west longitude. It is 171 kilometers (106 mi) in diameter and was named after the brothers Paul-Pierre Henry and Mathieu-Prosper Henry, both of whom were French telescope makers and astronomers. Mounds in craters like Henry are formed by the erosion of layers that were deposited after the impact.

Mound in Henry Crater

To the north and west of  Henry crater we enter the southern part of Arabia Terra.

Complex system of ridges in Arabia Terra

Southern Arabia Terra

Northeast of Henry Crater is Pasteur Crater also in the Arabia Region of Mars, located at 19.4° north latitude and 335.5° west longitude. It is 113 kilometers (70 mi) in diameter and was named after Louis Pasteur, a French chemist.  Dark sand dunes are clustered in the southwest of the crater. The orientation of the Barchan dunes suggest that they were generated by northeasterly winds. The source of the dune's sand appears to be local. Upwind of the dunes there is a small crater, Euphrates, within Pasteur crater that may have excavated sediments. The dark sediments have formed a patch at Euphrates' base. HiRISE imagery of the intracrater dunes within Pasteur crater over 1 Martian year indicate that the dunes are active with sand movement in a southwesterly direction.

Erosion in Pasteur Crater

Going to the northeast of that Crater we come to the Cassini Crater and just on it’s northern rim is Luzin Crater. Cassini Crater on Mars is named in honor of the Italian astronomer Giovanni Cassini.  The crater is approximately 415 km in diameter and can be found at 327.9°W and 23.8°N. It is in the Arabia Region of Mars.  Recent research leads scientists to believe that some of the craters in Arabia may have held huge lakes. Cassini Crater probably once was full of water since its rim seems to have been breached by the waters. Both inflow and outflow channels have been observed on its rim. The lake would have contained more water than Earth's Lake Baikal, our largest freshwater lake by volume.

Layers in the Cassini Crater Floor

 

Crater on the floor of Cassini crater, as seen by HI rise. The location is 24 degrees north latitude and 327.9 degrees west longitude.

Just to the southeast of Cassini Crater is the Indus Vallis Location is 18.8 degrees north and 39.8 degrees East.

Indus Vallis

Indus Vallis is a river valley in the Arabia Region of Mars. It is 307 km long and was named after the ancient and modern name for a river in Pakistan.

 

Geological History of the Arabia Region:
Recent studies, reported in the journal Icarus, have suggested that the area underwent several phases in its formation:

1. A large basin, maybe from an impact, was produced early in Martian history. It was so early that Mars still had a magnetic field generated by movements in a liquid core. Present day Arabia possesses a remnant magnetism from that ancient era.
2. Sediments flowed into the basin. Water entered the basin.
   
3. Because Tharsis, on the other side of Mars, became so massive, the area around Arabia was pushed out. As it bulged upward, there was increased erosion which exposed old layers. When portions of a planet that can be subject to erosion rise, there is greatly increased erosion; Earth's Grand Canyon became very deep because it was eroded into a high plateau.
   
4. Over the following 4 billion years, the area was modified by various geological processes. Central peaks and ejecta shapes indicate that parts of Arabia are still water enriched.

Continuing on a more southerly route from Cassini we come to a bigger valley the Scamander Vallis.

Northeast Extent of Scamander Vallis

Following Scamander Vallis southward we enter the Terra Sabaea area.  The Terra Sabaea area is the uplands of the Arabia Region and occupy almost a third of the Arabia Region mostly in the  southeast part.  Almost ESE of Scamander Vallis is Tikhonravov Crater.

Location is 12.8 N and 34.9 E.  Pedestal craters and layers in Tikhonravov Crater. in Arabia Region, as seen by Mars Global Surveyor (MGS), under the MOC Public Targeting Program. Layers may form from volcanoes, the wind, or by deposition under water. Some researchers believe this crater once held a massive lake.

How Pedestal Craters are formed

Tikhonravov Crater: is a large, eroded crater in the Arabia Region of Mars. It is 386.0 kilometers (240 mi) in diameter and was named after Mikhail Tikhonravov, a Russian rocket scientist. Tikonravov is believed to have once held a giant lake that drained into the 4500 km long Naktong-Scamander-Mamers lake-chain system. An inflow and outflow channel has been identified.  Recent research leads scientists to believe that some of the craters in Arabia may have held huge lakes. Cassini Crater and Tikonravov Crater probably once were full of water since their rims seem to have been breached by water. Both inflow and outflow channels have been observed on their rims. Each of these lakes would have contained more water than Earth's Lake Baikal, our largest freshwater lake by volume. The watersheds for lakes in Arabia seem to be too small to gather enough water by precipitation alone; therefore it is thought that much of their water came from groundwater.

Continuing southward into Terra Sabaea we follow the Scamander Vallis  into Arago Crater.

 

Elevation Map of Arago Crater

The crater’s location is 11.5°N 28.6°E. diameter 145 km.  Named after  Dominique F. Arago a French astronomer (1786-1853).

From there we follow another river valley southward the  Naktong Vallis.  It is an ancient river valley in the Arabia Region of Mars, located at 5.3 degrees north latitude and 327.1 degrees west longitude. It is 494 km long and was named after a river in Korea.  Naktong Vallis is part of the Naktong/Scamander/Mamers Valles lake-chain system that is comparable in length of Earth's largest system, like  the Missouri-Mississippi Rivers.

Naktong Vallis

East of Naktong Vallis at about 3°N is Janssen Crater.

Rock Outcrop in Janssen Crater

Janssen Crater is located at 3.3°N and 38.2°E.  Named after Pierre, Jules Janssen a Mathematician and Physicist  Born in Paris, in February 22nd 1824, and died in Meudon, in December 23rd 1907.

Terraforming Mars Phase 2:

The Surface Gravity & Magnetosphere on Mars is 38% of that on Earth. It is not known if this is enough to prevent the health problems associated with weightlessness.  Additionally, the low gravity (and thus low escape velocity) of Mars may render it more difficult for the planet to retain an atmosphere when compared to the more massive Earth and Venus. Earth and Venus are both able to sustain thick atmospheres, even though they experience more of the solar wind that is believed to strip away planetary volatiles (the atmosphere). Continuing sources of atmospheric gases on Mars might therefore be required to ensure that an atmosphere sufficiently dense for humans is sustained in the long term.  Mars lacks a magnetosphere, which poses challenges for mitigating solar radiation and retaining atmosphere. It is believed that fields detected on the planet are remnants of a magnetosphere that collapsed early in the planet's history.  The lack of a magnetosphere is thought to be one reason for the planet's thin atmosphere. Solar wind-induced ejection of Martian atmospheric atoms has been detected by Mars-orbiting probes. Venus, however, clearly demonstrates that the lack of a magnetosphere does not preclude a dense atmosphere. Earth abounds with water because its ionosphere is permeated with a magnetosphere. The hydrogen ions present in its ionosphere move very fast due to their small mass, but they cannot escape to outer space because their trajectories are deflected by the magnetic field. Venus has a dense atmosphere, but only traces of water vapor (20 ppm) because it has no magnetic field. The Martian atmosphere also loses water to space. Earth's ozone layer provides additional protection. Ultraviolet light is blocked before it can dissociate water into hydrogen and oxygen. Since little water vapor rises above the troposphere and the ozone layer is in the upper stratosphere, little water is dissociated into hydrogen and oxygen.  The Earth's magnetic field is 31 µT. Mars would require a similar magnetic field intensity to similarly offset the effects of the solar wind at a distance farther from the Sun. The technology for inducing a planetary scale magnetic field does not currently exist.

The Dream Phase 2 …………..