Small Pale Red Planet Issue 1 Phase 11

 

 Ismenius Lacus Region

MC-5

 

Topographical Map of the Ismenius Lacus Region

The southern and northern borders of the Ismenius Lacus Region are approximately 3,065 km (1,905 mi) and 1,500 km (930 mi) wide, respectively. The north to south distance is about 2,050 km (1,270 mi).  The Region covers an approximate area of 4.9 million square km, or a little over 3% of Mars’ surface area.

 

Image of the Ismenius Lacus Region

The Ismenius Lacus Region contains the Deuteronilus Mensae and Protonilus Mensae, two places that are of special interest to scientists. They contain evidence of present and past glacial activity. The Region also has a landscape unique to Mars, called Fretted terrain.  The northern part of this Ismenius Lacus is covered by the Acidalia Planitia.  The largest crater in the Region is Lyot Crater which contains channels probably carved by liquid water.

Lyot Crater with dunes and dust devil tracks

Lyot Crater: The northern plains are generally flat and smooth with few craters. However, a few large craters do stand out. The giant impact crater, Lyot, is easy to see in the central part of Ismenius Lacus. Lyot Crater is the deepest point in Mars's northern hemisphere. The image above of Lyot Crater Dunes shows a variety of interesting forms: dark dunes, light-toned deposits, and Dust Devil Tracks. Dust devils, which resemble miniature tornados create the tracks by removing a thin, but bright deposit of dust to reveal the darker underlying surface. Light-toned deposits are widely believed to contain minerals formed in water. Research, published in June 2010, described evidence for liquid water in Lyot crater in the past. 

Dunes on the Move in the Lyot Crater area

Channel and fan in Lyot Crater

South of Lyot Crater is the Deuteronilus Mensae:

Rough Terrain in Dueteronilus Mensae

 

Eroded terrain in Deuteronilus Mensae, as seen by HiRISE

Deuteronilus Mensae is a region on Mars 937 km across and centered at   43.9°N 337.4°W. It covers 344° -325° West and 40°-48° North. The Deuteronilus region lies just to the north of Arabia Terra and is included in the Ismenius Lacus Region. It is along the dichotomy boundary, that is between the old, heavily cratered southern highlands and the low plains of the northern hemisphere. The region contains flat-topped knobby terrain that may have been formed by glaciers at some time in the past.

Lineated Valley Fill and Lobate Debris Aprons in Deuteronilus Mensae

Many of the valley floors in the Dueteronilus Mensae region exhibit complex alignments of small ridges and pits often called "lineated valley fill." The cause of the small-scale texture is not well understood, but may result from patterns in ice-rich soils or ice loss due to sublimation (ice changing into water vapor). The linear alignment may be caused by downhill movement of ice-rich soil or by glacial flow. For example, flowing ice on Earth typically develops wrinkles or ridges and pits due to stresses in the ice as it moves. The result is flow patterns, called "stream lines" that follow the valleys and curve around obstacles. In this image, stream lines are diverted or curve around the mesas.

South of the Deuteronilus Mensae we come to the Deuteronilus Colles area also along  the Dichotomy boundary but closer to the Uplands of Arabia Terra. 

The Deuteronilus Colles Area

Features in the Deuteronilus Colles area  in Visible Light

The southeastern part of the Ismenius Lacus Region  contain part of the Uplands of Arabia Terra. As one enters the region one comes to the Mamers Valles, a giant outflow channel which runs from north to south. Mamers Vallis is a long, winding canyon in the north of Mars. It covers 1000 km, cutting through the cratered uplands of the Arabia Terra, from the Cerulli Crater to the Deuteronilus Mensae near the edge of Mars' vast northern lowlands. Through its midsection, it averages a width of 25 km and a depth of 1200 meters. the most popular theory states that the canyon was likely formed by either water or lava, with the flow from south to north and additional material flowing from the slope toward the valley floor. According to the most popular theory, linear features in the valley bottom indicate possible ice flows and that ice may currently be plentiful. Mamers Vallis is dated to the early Hesperian period, about 3.8 billion years ago.

 

Wide view of Mamers Vallis with cliffs, as seen by HiRISE.

Fretted terrain in Mamers Vallis

Just to the southeast of Mamers Vallis is Cerulli Crater:

 

Cerulli Crater Ejecta Valleys, as seen by HiRISE

Cerulli Crater is a crater in the Ismenius Lacus Region on Mars with a diameter of 130 km. It is located at 32.5° north latitude and 337.9° west longitude. It is named after Vicenzo Cerulli, an Italian astronomer (1859–1927).

Back to and east of Deuteronilus Mensae is the Protonilus Mensae.  The Protonilus Mensae is an area of Mars in the Ismenius Lacus Region. It is centered on the coordinates of 43.86° N and 49.4° E. Its western and eastern longitudes are 37° E and 59.7° E. North and south latitudes are 47.06° N and 39.87° N. Protonilus Mensae is between Deuteronilus Mensae and Nilosyrtis Mensae; all lie along the Martian dichotomy boundary (ancient shoreline).

 

Pits and cracks in Protonilus Mensae,

Fretted Terrain: The Ismenius Lacus Region contains several interesting features such as Fretted terrain, parts of which are found in Deuteronilus Mensae and Protonilus Mensae. Fretted terrain contains smooth, flat lowlands along with steep cliffs. The scarps or cliffs are usually 1 to 2 km high. Channels in the area have wide, flat floors and steep walls. Many buttes and mesas are present. In fretted terrain the land seems to transition from narrow straight valleys to isolated mesas. Most of the mesas are surrounded by forms that have been called a variety of names: circum-mesa aprons, debris aprons, rock glaciers.

Glaciers:  Glaciers formed much of the observable surface in large areas of Mars. Much of the area in the high latitudes, especially the Ismenius Lacus Region, is believed to  contain enormous amounts of water ice. In March 2010, scientists released the results of a radar study of the Deuteronilus Mensae area that found widespread evidence of ice lying beneath a few meters of rock debris. The ice was probably deposited as snowfall during an earlier climate when the poles were tilted more. It would be difficult to take a hike on the fretted terrain where glaciers are common because the surface is folded, pitted, and often covered with linear striations. The striations show the direction of movement. Much of this rough texture is due to sublimation of buried ice. The ice goes directly into a gas (this process is called sublimation) and leaves behind an empty space. Overlying material then collapses into the void.

A Delta in Ismenius Lacus, as seen by Themis. Location is 33.9 N and 17.5 E.

Deltas: Researchers have found a number of examples of deltas that formed in Martian lakes. Deltas are major signs that Mars once had a lot of water because deltas usually require deep water over a long period of time to form. In addition, the water level needs to be stable to keep sediment from washing away. Deltas have been found over a wide geographical range. Above, is a picture of  one in the Ismenius Lacus Region.

Coloe Fossae is a set of troughs in the Ismenius Lacus Region of Mars. It is centered at 36.5 degrees north latitude and 302.9 west longitude. It is 590 km long and was named after a classical albedo feature name.

Fretted Valleys in Coloe Fossae area

Fretted Valleys in Coloe Fossae area in Visible Light

Moreux Crater is a crater in the Ismenius Lacus Region on Mars with a diameter of 138 km. It is located at 42.1° north latitude and 315.6° west longitude It was named after Theophile Moreux, a French astronomer and meteorologist (1867–1954).

 

Moreux Crater moraines and kettle holes, as seen by HIRISE

Unusual surface patterns near the center of Moreux Crater suggest a complicated history of glacial flow. A series of ridges and troughs originating from the crater’s central peak to the west of this image terminate in this area in a jumble of twisted patterns and circular depressions.

Jumbled Flow Patters in Moreux Crater

The superposition of impact craters and sand dunes on top of these ridges and troughs suggests that the flow patterns are old and that any ice may be largely gone. The round depressions may have formed when large sections of relatively clean ice were left in place to melt or sublimate (evaporating ice directly to gas). The ridges would be analogous to moraines in Earth glaciers, formed from rock and debris mixed with the ice that flow with the glacier.  The complicated and twisting patterns indicate that the ice flowed into this area, which is at a lower elevation on the crater floor, and piled up behind itself as the flow stalled. Numerous boulders are also scattered over the surface of ridges and troughs. Boulders may have been carried into place with the ice and as the ice was removed, the boulders were left in place.   This the last major crater north of the Uplands of the  Sabaea Terra along the Dichotomy boundary until we come to the next major Region to the East.

Banded Bedrock of Terra Sabaea

Possible theories:  Such colorful bedrock is typical of ancient Mars, when water played a more active role in altering minerals. Tectonics is the movement of rocks under the great forces within a planet’s interior.  Mars probably had very active plate tectonics early in it’s history and may still be active today on a much smaller scale.  What we see today seems to be  driven mainly by gravity. The primary focus in tectonics is to understand the forces that are bending and breaking the rocks. The first step in gaining this understanding is to measure exactly how and when the rock were deformed. One idea is that the global scale tectonics on Mars can be related to the weight of Olympus Mons and the other volcanoes in the Tharsis area. This idea makes very specific predictions for how the deformation will be oriented (cracks will generally be "radial" (point to) Tharsis and ridges will be "concentric" to (encircle) Tharsis). Another basic question is whether the many fissures that are seen on the surface of Mars are formed by magma pushing up form underneath or if they formed first, producing an area of weakness that rising magma could exploit. Finally, the way the rocks bend or break tells us a lot about what they are made of. Most sedimentary rocks that have been laid down in water will bend easier than hard lava.

Small Pale Red Planet Issue 1 Phase 10

 

Mare Acidalium Region

MC – 4

 

 

Topographical Map of the Mare Acidalium Region

The southern and northern borders of the Region are approximately 3,065 km and 1,500 km wide, respectively. The north to south distance is about 2,050 km. The Region covers an approximate area of 4.9 million square km, or a little over 3% of Mars’ surface area. This area contains many bright spots on a dark background that may be mud volcanoes. There are also some gullies that formed by relatively recent flows of liquid water.

Image of the Mare Acidalium Region

This Region contains many interesting features, including gullies and possible shorelines of an ancient northern ocean. Some areas are densely layered. The boundary between the southern highlands and the northern lowlands lies in Mare Acidalium. 

At the 30 North mark we come to the northern part of Kasei Vallis Canyon and North Kasei Channel area located in the southern part of the Chryse Planitia.  Part of the topography map that is a part of the Mare Acidalium Region can be seen below:

The Kasei Valles system begins in Echus Chasma, runs northward, and appears to empty into Chryse Planitia.

Exploring the Mounds in Chryse Region

Further north is Bonestell Crater.  It is 42.4 km in diameter and was named after Chesley Bonestell, a famous American space artist (1888-1986), whose drawings inspired many young people to study the sciences.

Bedrock Outcropping at Bonestell Crater

High Altitude Slice of Bonestell Crater

Going further north, we come to the Acidalia Planitia or the Acidalia Plains.  The Acidalia Colles is a group of hills located in the Acidalia Planitia area of Mars, located at 50.9° north latitude and 23.1° west longitude. This group of hills occupies an area of 360 miles. 

 

The HiRISE image above of Acidalia Colles shows gullies in the northern hemisphere.

Gullies in Acidalia Planitia

Kunowsky Crater:  is a large crater in the Mare Acidalium Region of Mars, located at 57.1° north latitude and 9.7° west longitude. The crater is 67.4 km in diameter and was named after George K. Kunowsky, a German astronomer. Because it lies on a large flat plain, Kunowsky is easy to spot on maps and pictures.

Kunowsky Central Peak with strong Olivine Signature

Kunowsky Crater and Peak in visible light.

Arandas Crater:  is a crater in the Mare Acidalium Region of Mars, located 42.77° North and 15.17° West. It is 25.1 km in diameter and is named after a town in Mexico.

Central Peak of Arandas Crater

Part of the wall of Arandas Crater

The Cydonia area: is an area on the planet Mars, which has attracted both scientific and popular interest. The name originally referred to the albedo feature (distinctively colored area) that was visible from earthbound telescopes. The area borders plains of Acidalia Planitia and the Arabia Terra highlands. The area includes the Mars regions: "Cydonia Mensae", an area of flat-topped mesa-like features, "Cydonia Colles", and "Cydonia Labyrinthus", a complex of intersecting valleys. As with other albedo features on Mars, the name Cydonia was drawn from classical antiquity, in this case from Kydonia, a historic polis (or "city-state") on the island of Crete. As we head southeast, the first part of Cydonia that we run into will by the Cydonia Labyrinthus.

Polygonal fractured terrain of Cydonia Labyrinthus

 

Cydonia Labyrinthus in the Infrared

The next prominent feature we come to  in Cydonia contains the "Face on Mars"

The "Face on Mars," is of great interest to the public, is located near 40.8 degrees north and 9.6 degrees west, in the Cydonia area. When Mars Global Surveyor examined it with high resolution, the face turned out to be an eroded mesa.  The early Viking Orbiter image (inset is in bottom right corner) makes it look more like a face.  There are actually three faces on Mars. This one is probably the best known of the three.

3-D Video of the face on Mars.  I will leave it up to the reader to decide if someone made it or is a natural feature. 

 

Some believe there is a city and some pyramids  as well.  In the map above in the small box is the location of all of these features.  The Cydonia Colles is a group of small hills and knobs located south of the face.

A Youthful Crater in the Cydonia Colles area

Note that even though a crater might be called "youthful," it can still mean that the crater was formed tens of thousands of years ago, if not more.  Next, we come to Cydonia Mensae that borders Arabia Terra. 

 

Sample of Terraced Crater Walls Southeast of Cydonia Colles

Mud volcanoes:  Large areas of Mare Acidalium display bright spots on a dark background. It has been suggested that the spots are mud volcanoes. More than 18,000 of these features, which have an average diameter of about 800 meters, have been mapped. Mare Acidalium would have received large quantities of mud and fluids from outflow channels, so much mud may have accumulated there. The bright mounds have been found to contain crystalline ferric oxides. Mud volcanism here may be highly significant because long-lived conduits for upwelling groundwater could have been produced. These could have been habitats for microorganisms. Mud volcanoes could have brought up samples from deep zones that could therefore be sampled by explorers.

 

Mud volcanoes near the edge of the ejecta of a nearby crater, as seen by HiRISE.

Next the terrain becomes flat and rocky then goes uphill into Arabia Terra. Arabia Terra is a large upland region in the north-central region of Mars, it lies mostly in the Arabia Region, but also in the bottom SW corner of the Mare Acidalium 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.

Bamberg Crater: is an impact crater in the Mare Acidalium Region of Mars, located at 39.71 N and 356.9 E. It is 55.7 km in diameter and is named after a town in Germany.  It is the last location of note before the we enter the next major Region to the east.

 

Bamberg Crater

Small Pale Red Planet Issue 1 Phase 9

The Arcadia Region

MC-3

Topographical Map of the Arcadia Region  

It is important to understand that many of the places surveyed in this survey of Mars come from an aerial view by satellites or orbiters.  All of the ground photos were taken by the robotic explorers operating on the surface of Mars.  The longest distance any of them have traveled so far is only about 22 miles -not even a drop in the bucket. But their analysis of  the soil and rocks are very important and given time they will explore more of the planet.  So many parts of this survey are based on best guess science, geological comparisons with land formations on Earth our experience with craters like those on the moon.  When will humans come to walk on any of these places in this survey I do not to know. I do not know the future of Mars so I cannot say when it will or if it will happen at any given location.  But humans will definitely land somewhere on this planet one day.  One should remember that exploring a planet is a lot larger task than exploring a state or country on Earth  It is a very big place to say the least even though the planet is smaller than Earth.

 

Mars Arcadia Region Image

The southern and northern borders of the Arcadia Region are approximately 3,065 km and 1,500 km wide, respectively. The north to south distance is about 2,050 km. The Region covers an approximate area of 4.9 million square km, or a little over 3% of Mars’ surface area.  Several features found in this Region are interesting, especially gullies which are believed to be caused by relatively recent flows of liquid water.  The climate of this region is believed to be a mild north polar type.

Artynia Catena: is a feature in the Arcadia Region of Mars, located right on the border of the Diacria Region.   It is 263 km (163 mi) long and was named after a classical albedo feature at 54°N 137°W.

 

Close up of Pit Craters in Artynia Catena

 

High altitude view of chain of Pit Craters in Artynia Catena

This Region also contains Alba Patera (Alba Mons), the largest volcano (by area and volume) in the solar system and Tempe Terra, a highly fractured block of ancient crust about the size of Alaska.

Alba Mons (or Alba Patera):  is an immense, low-lying volcano located close to the northern Tharsis region of the planet Mars. It is the largest volcano on Mars in terms of area, with volcanic flow fields that extend for at least 1,350 km (840 mi) from its summit. That means it is spread into the Diacria region as previously mentioned.  But most of the volcano is in the Arcadia Region. Although the volcano has a span comparable to that of the United States, it reaches an elevation of only 6.8 km (22,000 ft) at its highest point. This is about one-third the height of Olympus Mons, the tallest volcano on the planet. The flanks of Alba Mons have very gentle slopes. The average slope along the volcano's northern (and steepest) flank is 0.5°, which is over five times lower than the slopes on the other large Tharsis volcanoes. In broad profile, Alba Mons resembles a vast but barely raised welt on the planet's surface. It is a unique volcanic structure with no counterpart on Earth or elsewhere on Mars.  Alba Mons has some of the oldest, extensively exposed volcanic deposits in the region. Geologic evidence indicates that significant volcanic activity ended much earlier at Alba Mons than at Olympus Mons and the Tharsis Montes volcanoes. Volcanic deposits from Alba Mons range in age from Hesperian to early Amazonian (approximately 3600 to 3200 million years ago).

Alba Mons Volcano

Fossae: Large troughs (long narrow depressions or fissures) are called fossae in the geographical language used for Mars. This term is derived from Latin; therefore, fossa is singular and fossae are plural. These troughs formed when the crust is stretched until it breaks. The stretching can be due to the large weight of a nearby volcano.  Fossae/pit craters are common near volcanoes in the Tharsis and Elysium system of volcanoes and here too as already noted (The Artynia Catena). A trough often has two breaks with a middle section moving down, leaving steep cliffs along the sides; such a trough is called a graben. Pit craters are often associated with graben. Pit craters do not have rims or ejecta around them, like impact craters do. Studies have found that on Mars a fault may be as deep as 5 km, that is the break in the rock goes down to 5 km. Moreover, the crack or fault sometimes widens or dilates. This widening causes a void to form with a relatively high volume. When surface material slides into the void, a pit crater or a pit crater chain forms. On Mars, individual pit craters can join to form chains or even to form troughs that are sometimes scalloped. Knowledge of the locations and formation mechanisms of pit craters and fossae is important for the future colonization of Mars because they may be reservoirs of water.

Tantalus Fossae: is a group of troughs in the Arcadia Region of Mars, located at 50.9° north latitude and 97.5° west longitude. They are about 2,400 km long.  It is the first feature we come to that separates the Mons Alba from the Tempe Terra.

Close Up of Terrain of Tantalus Fossae

 

Infrared view of Tantalus Flossae on the E. slopes of Mons Alba

Tractus Catena: is the next group of features we come across as we head eastward toward Tempe Terra. Tractus Catena  is a set of pits in the Arcadia Region of Mars. Its location is centered at   28.17°N 102.77°W. It is 897 km (557 mi) long.  The line of pits that make up Tractus Catena make it related to fossae, which are common on Mars.

 

Tractus Catena, as seen by HiRISE. Scale bar is 1,000 m (3,300 ft) long.

Martian gullies are small, incised networks of narrow channels and their associated downslope sediment deposits, found on the planet of Mars. They are named for their resemblance to terrestrial gullies. First discovered on images from Mars Global Surveyor, they occur on steep slopes, especially on the walls of craters. Usually, each gully has a dendritic alcove at its head, a fan-shaped apron at its base, and a single thread of incised channel linking the two, giving the whole gully an hourglass shape. They are believed to be relatively young because they have few, if any craters. A subclass of gullies is also found cut into the faces of sand dunes, that are themselves considered to be quite young.  Most gullies occur 30 degrees pole- ward in each hemisphere, with greater numbers in the southern hemisphere. Some studies have found that gullies occur on slopes that face all directions; others have found that the greater number of gullies are found on pole-ward facing slopes, especially from 30-44 degrees S. Although thousands have been found, they appear to be restricted to only certain areas of the planet. In the northern hemisphere, they have been found in Arcadia Planitia, Tempe Terra, Acidalia Planitia, and Utopia Planitia and in southern Regions of the planet as well (which we will come to in due time).

Enipeus Vallis: is a valley in the northern hemisphere of the planet Mars. It is centered at lat. 37°N, long. 267°E. on the Arcadia Region on the border of the Tempe Terra plateau.    Enipeus Vallis follows a gently sinuous, north-south path for a distance of about 357 km (222 mi). It is likely an ancient watercourse that formed during the early Hesperian (or late Noachian) period, around 3.7 billion years ago.  Enipeus Vallis is mapped as a valley network. Valley networks are branching systems of valleys on Mars that superficially resemble terrestrial river drainage basins. They are abundant in the equatorial and southern highlands of the planet but less common in the northern hemisphere.  Enipeus Vallis is a single trunk valley, with no large tributaries. The valley is widest (about 10 km) at its southernmost reach near Lat. 33.6°N. and rapidly tapers northward, maintaining a regular width of 3 to 5 km throughout most of its course. 

Enipeus Vallis

Tempe Terra: is a heavily cratered highland region in the northern hemisphere of the planet Mars. Located at the northeastern edge of the Tharsis volcanic province, Tempe Terra is notable for its high degree of crustal fracturing and deformation. It also contains a large number of small shield volcanoes and other volcanic structures. Tempe Terra is centered at   39.7°N 289°E Coordinates: 39.7°N 289°E and spans about 2,700 km at its broadest extent. The region extends from about 30° to 54°N and from 265° to 310°E, covering approximately 2.1 million km2, or an area roughly equivalent to that of Saudi Arabia. Acidalia Planitia borders it to the east, to the north by the low-lying plains of Arcadia and Vastitas Borealis, and to the south by the huge outflow channel Kasei Vallis. Tempe Terra occupies a transition zone between the old, heavily cratered highlands of the Martian south and the geologically younger, lowland terrain of the north. Tempe Terra contains the northernmost exposures of ancient highland crust on the planet. The region is transected by large numbers of linear to curvilinear normal faults and grabens with ages that span much of Mars' geologic history.

Important  Locations in the Arcadia Region on Mars

Mareotis Fossae:  is a group of troughs in the Arcadia Region of Mars, located at 44° north latitude and 75.3° west longitude. It is about 1,860 km long.  It runs from the southeastern to the northeastern part of the Tempe Terra on an angle.

Central Peak crater along Dichotomy Boundary in Mareotis Fossae Region

 

 

High Altitude view of Central Peak crater along Dichotomy Boundary in Mareotis Fossae Region.

Tempe Fossae: is a group of troughs in the Arcadia Region of Mars, located at 40.2° north latitude and 71.4° west longitude. It is about 2,000 km long. Troughs, like this one are called fossae on Mars. The Tempe Fossae goes right through the center of the Tempe Terra.

Sinuous Channels in Tempe Fossae.

More Features of Tempe Terra going from east to west

Small Pale Red Planet Issue 1 Phase 8

The Diacria Region

MC-02

 

Image of The Diacria Region

The southern and northern borders of the Diacria Region are approximately 3,065 km (1,905 mi) and 1,500 km (930 mi) wide, respectively. The north to south distance is about 2,050 km (1,270 mi). The Region covers an approximate area of 4.9 million square km, or a little over 3% of Mars’ surface area.

 

Topographical Map of the Diacria Region

The Phoenix Lander’s landing site (68.22° N, 234.25° E) lies about 186 km north of the northeastern quarter of the Diacria Region. The landscape viewed by the Phoenix lander is probably representative of a large portion of the terrain in the northern Diacria Region.
The highest elevation about 3.5 km (3,500 m) above datum (Mars "sea level") on the western flank of the Alba Mons volcano in the southeastern portion of the Region.

The Alba Mons volcano in SW corner of Region

Western flank of Alba Mons:  The western flank of the Alba Mons volcano makes up the eastern and southeastern edge of the Region. In terms of area, Alba Mons (formerly, Alba Patera) is the largest volcanic feature on Mars. The flank has a very low slope (l° or less) and is characterized by lava flows and an outwardly radiating array of ridges and channels. Some of the channels have a drainage pattern that resembles that formed by rainwater on the slopes of terrestrial volcanoes. However, many other channels on the flanks of Alba Mons were clearly formed by flowing lava. The western flank of the volcano also contains some NW-SE trending grabens (Cyane Fossae).

Terrain of the Cyane Fossae area on the west flank of Alba Mons

An image from High Resolution Imaging Science Experiment (HiRISE) on the Mars Reconnaissance Orbiter (MRO) beautifully shows a line of rimless pit craters in Cyane Fossae. The pits may have formed by the collapse of surface materials into open fractures created as magma intruded the subsurface rock to form dikes.

Pit craters in Cyane Fossae.

The northern and western areas of the Region lie in the northern lowland plains of Mars and cover portions of Amazonis Planitia (in the south), Arcadia Planitia (west central) and Vastitas Borealis (in the north).

Milankovic Crater: is a crater in the Diacria Region  of Mars, having a diameter of 118.4 km. It is located at 54.7° north latitude and 146.7° west longitude. The crater is easy to see on Mars photographs because it lies north of Olympus Mons and sits by itself in the flat plain of Vastitas Borealis. It is named after Milutin Milanković, a Serbian geophysicist and astrophysicist, who lived from 1879 to 1958.

Milankovic Crater

The Arcadia Planitia is a smooth plain with fresh lava flows and Amazonian volcanic flows on Mars. Giovanni Schiaparelli named it in 1882 after the Arcadia region of ancient Greece. It dates from the Amazonian period's Arcadia formation's lava flows and small cinder cones. It includes a more recently developed large region of Aeolian materials derived from periglacial processes. It is located northwest of the Tharsis Region in the northern lowlands, spanning the region 40-60° North and 150-180° West in  the Cebrenia Region and centered at  46.7°N 192.0°E. Arcadia marks a transition from the thinly cratered terrain to its north and the very old cratered terrain to the south. On its east, it runs into the Alba Mons volcanoes. Its elevation relative to the geodetic datum varies between 0 and -3 km.   In many of the low areas of Arcadia, one finds grooves and sub-parallel ridges. These indicate movement of near surface materials and are similar to features on earth where near surface materials flow together very slowly as helped by the freezing and thawing of water located between ground layers. This supports the proposition of ground ice in the near surface of Mars in this area. This area represents an area of interest for scientists to investigate further. Arcadia Planitia and Southern Vastitas Borealis:  The geologic history and origin of the northern plains are complex and still poorly understood. Many of the landforms resemble periglacial features seen on Earth, such as moraines, ice-wedged polygons, and pingos. Arcadia Planitia and Vastitas Borealis likely consist of a hodgepodge of old lava flows, ice-related features, and reworked sediments of diverse origin. Some theorize that oceans or large lakes once covered the northern plains.

Details of the  Arcadia Planitia Region

The Amazonis Planitia: is one of the smoothest plains on Mars. It is located between the Tharsis and Elysium volcanic provinces, to the west of Olympus Mons, in the Amazonis and Memnonia Regions, centered at 24.8°N 196.0°E. The plain's topography exhibits extremely smooth features at several different lengths of scale.  Part of it is located in the southwest part of the Daicria Region.

Amazonis Planitia area

 

Acheron Fossae is a trough in the Diacria Region of Mars. Its location is centered at 37.67° north latitude and 135.87° west longitude. It is 718 km long and is named after a classical albedo feature at 35°N, 140°W . The trough has seen intensive tectonic activity in the past.

The Acheron Fossae Trough

Lycus Sulci (Olympus Mons Aureole):  Lycus Sulci (24.6° N, 219° E) is the name applied to the northwestern portion of a larger terrain feature that partially encircles Olympus Mons and extends up to 750 km from the giant shield volcano’s base.  An aureole is a  zone of altered  rock around a volcano.

A view Near the Lycus Sulci area

This feature, called the Olympus Mons aureole, consists of several large lobes and has a distinctive corrugated or grooved surface texture. East of Olympus Mons, the aureole is partially covered by lava flows, but where it is exposed it goes by different names (Gigas Sulci, for example).The origin of the aureole remains debated, but it was likely formed by huge landslides or gravity-driven thrust sheets that sloughed off the edges of the Olympus Mons shield

The lava flows of the Lycus Sulci coming from Mons Olympus

The Erebus Montes: Grooves indicate movement. Westward from Lycus Sulci, across the flat plains of Amazonis Planitia, lies an elongated region of knobby terrain called Erebus Montes (Erebus Mountains). The region contains hundreds of clustered to isolated hillocks that stand 500 to 1,000 m above the surrounding plains. The presence of numerous partly filled "ghost" craters in the area indicates that the hills represent the high-standing remnants of ancient highland crust that was inundated by lava flows and (possibly) alluvial sediments from Tharsis in the southeast and the Elysium volcanic province to the west.

The Erebus Montes