Small Pale Red Planet Issue 2 Phase 2

Amazonis Region
MC-8

 

Topographical Map of the Amazonis Region

This Region covers the area from 135°- 180° East longitude and 0° to 30° north latitude on Mars. This area is considered to be among the youngest parts of Mars because it has a very low density of craters.

 

Image of the Amazonis Region
 

The Amazonia period is named after this area. This Region
n contains special, unusual features called the Medusae Fossae Formation and the Lycus Sulci.

Coming from the northwest into the Amazonis Region we come to a hilly region called the Tartarus Colles.  The Tartarus Colles only occupies the northwest corner of the Amazonia Region.  It is located roughly from 20-30 N to about 185°E.  The rest of the Tartarus Colles lies to the west in the Elysium Region.
 

Cratered Cones and Dissected Mantle in Tartarus Colles.

 

Mars is fundamentally a volcanic planet. Geologic mapping of Mars shows that about half the surface seems to be covered with volcanic materials that have been modified to some extent by other processes (such as meteorite impacts, blowing wind, floods of water, and sand). Mars has the largest volcanoes in the entire Solar System. The great volumes of erupted lava have had a profound impact on the entire planet, by extracting heat and erupting selected chemicals from within, then adding large amounts of acidic gas to the atmosphere, which provided heat to melt frozen water in the crust. Mars cannot be understood without studying its volcanoes.   We see the results of these actions today when the planet is no longer as active as it once was in the past.

 

Tartarus Colles Channel, as seen by HiRISE. Scale bar is 500 meters long. Location is 24.5 degrees north latitude and 188.1 degrees east longitude. The Mars Reconnaissance Orbiter’s HiRISE took the image.

 

South of this region, we come to Marte Vallis.  Marte Vallis is a valley in the Amazonis Region of Mars, located at 15 North and 176.5 East. It is 185 km long and was named after the Spanish word for “Mars”.
 

Marte Vallis

 

It has been identified as an outflow channel, carved in the geological past by catastrophic release of water from aquifers beneath the Martian surface.  Marte Vallis is the site of the first discovery of columnar jointing on Mars.
 

This is an example of Columnar Jointing on Earth

 

Marte Vallis Streamlined land forms

 

To the east is 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.and 196.0°E. The plain's topography exhibits extremely smooth features at several different lengths of scale.  Only approximately 100 million years old, these plains provide some of the fewest sedimentary layers impeding viewing of the Martian terrain, and closely resemble the composition of Earth's Iceland formed by free-flowing lava across great plains.
 

Amazonis Planitia

The entire contemporary era on Mars has been named the Amazonian Epoch because researchers originally (and incorrectly) thought Amazonis Planitia to be representative of all Martian plains. Instead, over the past two decades, researchers have realized that the area's youth and extremely smooth surface actually distinguish the area from its neighbors. It is even possible that the area possessed distinctive characteristics when this part of Mars was under water. Although the full implications of the Region’s youth have not yet been determined, the nature of the area (i.e. lack of sedimentary rock) has at least provided researchers evidence that this area is most likely to provide future discoveries, and as such, has been proposed as a future site for most NASA landings.

Just south of the Marte Vallis is Petit Crater.
 

Pettit Crater Rim, as seen by HiRISE. Location is 12.5 degrees north latitude and 185.4 degrees east longitude.

 

This crater is 92.49 km in diameter.  It was named after the American Astronomer Edison Petit (1890-1962).

There are hundreds of thousands of craters on Mars, but only some of them have names.  Large Martian craters (greater than 60 km in diameter) are named after famous scientists and science fiction authors; smaller ones (less than 60 km in diameter) get their names from towns on Earth. Craters cannot be named for living people, and small crater names are not intended to be commemorative - that is, a small crater is not actually named after a specific town on Earth, but rather its name comes at random from a pool of terrestrial place names, with some exceptions made for craters near landing sites.

Going southeast, we come to Nicholson Crater, which straddles the equator.  Part of if is in the Amazonis Region and part of it is in the Memnonia Region.
 

Nicholson Crater

 

Nicholson is a crater on Mars centered at 0.1° N and 164.5° W. It is 62 miles wide (100 km). Nicholson is a good marker for the equator as it sits almost directly on the Martian equator. It is named after Seth Barnes Nicholson, an American astronomer. Nicholson is notable for its central peak, which rises in a high mound 3.5 km above the crater floor. This rounded peak is riddled with channels, which may have been eroded by wind or even water.

Nicholson Crater and surrounding territory

 

Many places on Mars show dark streaks on steep slopes like crater walls. It seems that the youngest streaks are dark; they become lighter with age. Often they begin as a small narrow spot then widen and extend downhill for hundreds of meters. They have been seen to travel around obstacles, like boulders. Several ideas have been advanced to explain the streaks. Some involve water or even the growth of organisms. It is most generally accepted that they represent avalanches of dust. However, more recently a theory has come out that these streaks could have been caused by melting dry ice.
 

Dark streaks seen in the central mound of Nicholson Crater.

 

Going east, we come to Medusae Fossae Formation, which includes the Eumenides Dorsa..  The Medusae Fossae Formation is located right on the equator also. It starts in the Amazonis Region at about 10°N and  199°E.  It extends across the equator into the Memnonia Region to the south.

 

Plateau made up of Medusae Fossae materials and rootless cones, as seen by HiRISE.

 

The Amazonis Region is of special interest to scientists because it contains a big part of a formation, called the Medusae Fossae Formation.

 

 

 

Sinuous Ridges Cutting Geological Units of the Medusae Fossae Formation
 

 

 

 A soft, easily eroded deposit extends for nearly 1,000 km along the equator of Mars. The surface of the formation has been eroded by the wind into a series of linear ridges called yardangs.
 

Yardangs in the Medusae Fossae formation, as seen by HiRISE

 

These ridges generally point in direction of the prevailing winds that carved them and demonstrate the erosive power of Martian winds. The easily eroded nature of the Medusae Fossae Formation suggests that it is composed of weakly cemented particles, and was most likely formed by the deposition of wind-blown dust or volcanic ash. The Medusae Fossae Formation could have easily been formed from ash from the volcanoes Apollinaris Mons, Arsia Mons, and/or possibly Pavonis Mons.

 

Medusae Fossae Formation and its location relative to Olympus Mons, as seen by THEMIS.

In this region, we only come near to the western part of the basal scarp of the Olympus Mons Volcano.  But first we have to go through the Lycus Sulci area to get to it.

The Lycus Sulci is very rugged terrain  that extends from the base of Olympus Mons. The furrows are huge—up to a full kilometer deep. It would be extremely difficult to walk across it or to land a space ship there.
 

Surface features of Lycus Sulci, as seen by HiRISE

 

Lycus Sulci is a feature in the Amazonis Region on Mars, with its location centered at 24.6° north latitude and 141.1° east longitude. It is 350 km long and is named after a classical albedo feature name.  The Lycus Sulci surrounds the western side of the Olympus Mons.

The Lycus Sulci in Amazonis, as seen by THEMIS.

 

"Sulci" in Mars geography language means a furrow, like a furrow on a brain's surface. These Sulci spread out from the basal scarp of Olympus Mons.
 

Map Location of Lycus Sulci around the western scarp of Mons Olympus

 

Perspective of the Basal Scarp of Mons Olympus