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
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