Oxia Palus Region
MC-11
Topographical Map of the Oxia Palus Region
The Region covers the region of 0° to 45° west longitude and 0° to 30° north latitude on Mars. Mars Pathfinder landed in the Oxia Palus Region on July 4, 1997.
Image of Oxia Palus Region
Crater names in Oxia Palus are a Who's Who for famous scientists. Besides Galilaei and DaVinci, some of the people who discovered the atom and radiation are honored there: Curie, Becquerel, and Rutherford. Mawrth Vallis was strongly considered as a landing sites for NASA's next Mars rover, the Mars Science Laboratory. This Region contains abundant evidence for past water in such forms as river valleys, lakes, springs, and chaos areas where water flowed out of the ground. A variety of clay minerals have been found in Oxia Palus. Clay is formed in water, and it is good for preserving microscopic evidence of ancient life. Recently, scientists have found strong evidence for a lake located in the Oxia Palus quadrangle that received drainage from Shalbatana Vallis.
Landforms in Xanthe Dorsa
Going south to about 16°N and 317°E we come to a major river valley called Shalbatana Vallis, which goes south over the Equator into the Margaritifer Sinus Region.
Shalbatana Vallis in the Infrared This location was shot of the lower part at about 5°N.
Shalbatana Vallis form HiRISE
Shalbatana Vallis is an ancient water-worn river valley on Mars, located in the Oxia Palus Region at 7.8° north latitude and 42.1° west longitude. It is the westernmost of the southern Chryse outflow channels. Beginning in a zone of chaotic terrain, at 0° latitude and 46° W longitude, it ends in Chryse Planitia.
Possible Lake Margin in Shalbatana Vallis
Shalbatana Vallis contains the first definitive evidence of a Martian shoreline. This shoreline was part of an ancient lake 80 square miles (210 km2) in size and 1,500 feet (460 m) deep. The study carried out with HiRISE images indicates that water formed a 30 miles (48 km) long canyon that opened up into a valley, deposited sediment, and created a delta. This delta and others around the basin imply the existence of a large, long-lived lake. Of special interest is evidence that the lake formed after the warm, wet period was thought to have ended. So, lakes may have been around much longer than previously thought.
Shalbatana Vallis travels through another area that is called Xanthe Terra. Xanthe Terra: is a large area on Mars, centered just north of the Martian equator. Its coordinates are: 3°N 312°E and it covers 2465 km at its broadest extent. Its name means "golden-yellow land." It is in the Lunae Palus quadrangle and the Oxia Palus quadrangle. Images from Mars Express, Mars Global Surveyor, and the Mars Reconnaissance Orbiter have revealed ancient river valleys and deltas. The deltas show many thin layers just as deltas on Earth. Scientists speculate that features in Xanthe Terra show evidence of precipitation on early Mars.
Chaos Region in Xanthe Terra
Next we come to Hydroates Chaos on the Equator. There are many chaos areas in the Oxia Palus Region of Mars.
Mesas and Buttes of Hydroates Chaos
Hydroates Chaos is an equatorial region of chaotic terrain located near some of the large outflow channels on Mars. Chaotic terrain near the outflow channels (ancient flood channels) is thought to form when ices beneath the surface rapidly become liquid or gaseous and escapes, and the remaining solid material collapses. Chaotic terrain is called "chaotic" because it consists of a large jumble of randomly shaped mesas (hills) and troughs. Many regions of chaotic terrain are located at the head (start) of the outflow channels, suggesting that the origins of the two classes of feature might be related to each other. The mesa located in the center of the image has elongated depressions that might be evidence of past fluvial activity.
Tiu Valles
Tiu Valles is an outflow channel in the Oxia Palus quadrangle of Mars, located at 15.9° North and 35.7° West. It is 1,720 km long and was named after the word for "Mars" in old English (West Germanic). It seems to get its start in the south in the Hydroates Chaos. It head northwards and passes to the west of the Mojave Crater which is bordered on the East by the Chryse Chaos area.
Mojave Crater
Mojave Crater which is located between the Chryse Chaos and the Tiu Valles and has alluvial fans that look remarkably similar to landforms in the Mojave Desert in the American southwest. Fans inside and around the outside of Mojave Crater on Mars are a perfect match to Earth's alluvial fans. As on Earth, the largest rocks are near the mouths of the fans. Because channels start at the top of ridges, it is believed they were formed by heavy downpours. Researchers have suggested that rain may have initiated by impacts. Mojave Crater is approximately 2,604 meters (1.63 miles) deep. Based on its diameter and depth, researchers believe it is very young. It has not been around long enough to accumulate material and start to fill. It is giving scientists great insight into impact processes on Mars since it is so fresh.
Central Peak of Sagan Crater
Sagan Crater is an impact crater in the Oxia Palus Region of Mars. It is located at 10.8° N and 30.7° W. It is named after Carl E. Sagan, an American astronomer (1934–1996). Dr. Sagan was a founder of the Planetary Society.
Just to the northwest lies Masursky Crater. The Chryse Chaos has become part of the crater floor.
Chaotic Terrain in Masursky Crater
Going north from here we come to the Ares Vallis. It too is a very long ancient Martian river valley that crosses the Equator and extends into the next Region to the south.
The Ares Vallis Region
The Mars Pathfinder is an American spacecraft that landed a base station with a roving probe on Mars in 1997. It consisted of a lander, renamed the Carl Sagan Memorial Station, and a lightweight (10.6 kg/23 lb.) wheeled robotic Mars rover named Sojourner. Launched on December 4, 1996 by NASA aboard a Delta II booster a month after the Mars Global Surveyor was launched, it landed on July 4, 1997 on Mars's Ares Vallis, in the Chryse Planitia in the Oxia Palus Region. The lander then opened, exposing the rover which conducted many experiments on the Martian surface. The mission carried a series of scientific instruments to analyze the Martian atmosphere, climate, geology and the composition of its rocks and soil.
Robotic Rover Sojourner
The landing site was an ancient flood plain in Mars's northern hemisphere called "Ares Vallis" ("the valley of Ares", the ancient Greek equivalent of the ancient Roman deity Mars) and is among the rockiest parts of Mars. Scientists chose it because they found it to be a relatively safe surface to land on and one that contained a wide variety of rocks deposited during a catastrophic flood. After the landing, at the coordinates 19.13°N 33.22°W succeeded, the landing site received the name The Carl Sagan Memorial Station in honor of the astronomer.
The Mars Pathfinder
Types of rocks: Results of Mars Pathfinder's Alpha Proton X-ray Spectrometer indicated that some rocks in the Oxia Palus quadrangle are like Earth's andesites. The discovery of andesites shows that some Martian rocks have been re-melted and reprocessed. On Earth, Andesite forms when magma sits in pockets of rock while some of the iron and magnesium settle out. Consequently, the final rock contains less iron and magnesium and more silica. Volcanic rocks are usually classified by comparing the relative amount of alkalis (Na2O and K2O) with the amount of silica (SiO2). Andesite is different than the rocks found in meteorites that have come from Mars.
The Sojourner Rover is taking its Alpha Proton X-ray Spectrometer measurement of the Yogi Rock. Note: Sojourner Rover was the rover part of the Mars Pathfinder. It rolled off of the lander. This picture was taken by the lander.
By the time that final results of the mission were described in a series of articles in the Journal Science (December 5, 1997), it was believed that the rock Yogi contained a coating of dust, but was similar to the rock Barnacle Bill another rock that was examined. Calculations suggest that the two rocks contain mostly the minerals orthopyroxene (magnesium-iron silicate), feldspars (aluminum silicates of potassium, sodium, and calcium), quartz (silicon dioxide), with smaller amounts of magnetite, ilmenite, iron sulfide, and calcium phosphate. By taking multiple images of the sky at different distances form the sun, scientists were able to determine that size of the particles in the pink haze was about 1 micrometer in radius. The color of some soils was similar to that of an iron oxyhydroxide phase which would support a warmer and wetter climate in the past Pathfinder carried a series of magnets to examine the magnetic component of the dust. Eventually, all but one of the magnets developed a coating of dust. Since the weakest magnet did not attract any soil, it was concluded that the airborne dust did not contain pure magnetite or just one type of maghemite. The dust probably was an aggregate possibly cemented with ferric oxide (Fe2O3). Using much more sophisticated instruments, Mars Spirit Rover found that magnetite could explain the magnetic nature of the dust and soil on Mars. Magnetite was found in the soil and that the most magnetic part of the soil was dark. Magnetite is very dark. Using Doppler tracking and two-way ranging, scientists added earlier measurements from the Viking landers to determine that the non-hydrostatic component of the polar moment of inertia is due to the Tharsis bulge and that the interior is not melted. The central metallic core is between 1300 km and 2000 km in radius.
Sunset at the Mars Pathfinder location
Difference in size of spacecraft through wheel size comparison: Sojourner, Mars Exploration Rovers (Opportunity & Spirit), Mars Science Laboratory.
Just to the north the Ares Valles joins the Tiu Valles. Tiu Valles Ridges, were seen by HiRISE. The ridges were probably formed by running water. The Tiu Valles runs just west of where the Mars Pathfinder landed and heads north of there for a considerable distance.
Towards the northern end of the Tiu Valles is Kipini Crater.
Small Very Fresh Crater on South End of Kipini Crater Floor
Kipini Crater is an impact crater in the Oxia Palus Region of Mars. It is located at 26.1° N and 31.6° W It is named after a Town in Kenya.
Heading back down south again we come to Mawth Vallis. Mawrth Vallis (Mawrth means "Mars" in Welsh) is a valley on Mars located at 22.3°N, 343.5°E with an elevation approximately two kilometers below datum. It is an ancient water outflow channel with light-colored clay-rich rocks. Mawrth Vallis is one of the oldest valleys on Mars. It was formed in and subsequently covered by layered rocks, from beneath which it is now being exhumed.
Mawrth Valles
Marwrth Vallis as seen by Themis. The location is 22.3 degrees north latitude and 15.9 degrees west longitude.
Mawrth Vallis Geodiversity
Mawrth Vallis was strongly considered as a landing site for NASA's next Mars rover, the Mars Science Laboratory. This Region contains abundant evidence for past water in such forms as river valleys, lakes, springs, and chaos areas where water flowed out of the ground. A variety of clay minerals have been found in Oxia Palus. Clay is formed in water, and it is good for preserving microscopic evidence of ancient life.
Just west of Mawth Vallis is McLaughlin Crater. McLaughlin Crater is an old crater in the Oxia Palus Region of Mars, located at 21.9°N 337.63°E. It is 90.92 km (56.50 mi) in diameter and 2.2 km (1.4 mi) deep. The crater was named after Dean B. McLaughlin, an American astronomer (1901-1965). The Mars Reconnaissance Orbiter has found evidence that the water came from beneath the surface about 2 billion years ago and remained long enough to make carbonate-related clay minerals found in layers.
McLaughlin Crater
These photos of a huge crater on Mars suggest water may lurk in crevices under the planet's surface, hinting that life might have once lived there, and raising the possibility that it may live there still, researchers say. Future research looking into the chances of life on Mars could shed light on the origins of life on Earth, scientists added. The discovery came from a study of images by NASA's powerful Mars Reconnaissance Orbiter that revealed new evidence of a wet underground environment on the Red Planet. The images focused on the giant McLaughlin Crater, which is about 57 miles (92 kilometers) wide and so deep that underground water appears to have flowed into the crater at some point in the distant past. Today, the crater is bone-dry but harbors clay minerals and other evidence that liquid water filled the area in the ancient past. "Taken together, the observations in McLaughlin Crater provide the best evidence for carbonate forming within a lake environment instead of being washed into a crater from outside," said study lead author Joseph Michalski, of the Planetary Science Institute in Tucson, Arizona.
Going straight south and crossing the Ares Valles upstream we come to the Margaritifer Terra. Margaritifer Terra is an ancient, heavily cratered region of Mars. It is located in a region both south and north of the equator and covers 2600 km at its widest extent. The area reveals "chaos terrain", outflow channels, and alluvial plains that are indicative of massive flooding. Wind erosion patterns are also in evidence. The region within the terra shows some of the highest valley network densities on the planet. Then at 13°N and 338°E the Ares Valles comes to a fork and just due south of that fork at a short distance is the Aram Chaos.
The Aram Chaos is in an ancient impact crater near the Martian equator, close to Ares Vallis. About 280 kilometers (170 mi) across, Aram Chaos lies in a region called Margaritifer Terra, where many water-carved channels show that floods poured out of the highlands onto the northern lowlands ages ago. The Thermal Emission Imaging System (THEMIS) on the Mars Odyssey orbiter found gray crystalline hematite on the floor of Aram. Hematite is an iron-oxide mineral that can precipitate when ground water circulates through iron-rich rocks, whether at normal temperatures or in hot springs. The floor of Aram contains huge blocks of collapsed, or chaotic, terrain that formed when water or ice was catastrophically removed.
Erosion in Aram Chaos, as seen by Themis. Image location is 2.8 degrees north latitude and 21.1 degrees west longitude. Picture taken with Mars Odyssey's THEMIS.
In Aram Chaos, however, the released water stayed mostly within the crater's ramparts, eroding only a small, shallow outlet channel in the eastern wall. Several minerals including hematite, sulfate minerals, and water-altered silicates in Aram suggests that a lake probably once existed within the crater. Because forming hematite requires liquid water, which could not long exist without a thick atmosphere, Mars must have had a much thicker atmosphere at some time in the past, when the hematite was formed.
Blocks in Aram showing possible source of water, as seen by THEMIS. This is the Chaos that some claim was an artificially made city.
Aram Chaos Crater
Going east we cross the Ares Valles again and come to Crommlin Crater, that is a part of a region called Meridiani Planum which also straddles the Equator. Crommlin Crater is a little over 100 kilometers (62 miles) across and contains a mound of layered rock deposits. Layering in geologic materials is interesting because it represents a record of deposition over time. By studying such layered sequences, scientists attempt to tell what the local climate and environment were like in the past. Crommlin Crater is an impact crater in the Oxia Palus Region of Mars. It is located at 5.1° north and 10.2° west. It was named after Andrew C. Crommlin, a British astronomer (1865–1939).
Crommlin Crater Layered Deposit, as seen by HiRISE. The color blue in the photo is a false color.
Crommlin Crater contains a large mound that shows dozens of regular spaced layers.
Crommlin Crater contains a layered mound that is higher than its rim. This drawing shows how it was formed when much of the material was eroded away. Many craters on Mars have a mound or mass of material in their centers that are remains of deposited sediments.
Going northeast from here we come to Vernal Crater also located in Meridiani Planum. A study of images taken with the High Resolution Imaging Science Experiment (HiRISE) on the Mars Reconnaissance Orbiter strongly suggests that hot springs once existed in Vernal Crater, in the Oxia Palus Region. These springs may have provided a long-time location for life. Furthermore, mineral deposits associated with these springs may have preserved traces of Martian life.
Hydrothermal springs in Vernal crater, as seen by HiRISE. Location is 5.6 degrees north latitude and 4.4 degrees west longitude.
In Vernal Crater on a dark part of the floor, two light-toned, elliptical structures closely resemble hot springs on the Earth. They have inner and outer halos, with roughly circular depressions. A large number of hills are lined up close to the springs. These are thought to have formed by the movement of fluids along the boundaries of dipping beds. The picture above shows these springs. One of the depressions is visible. The discovery of opaline silica by the Mars Rovers, on the surface also suggests the presence of hot springs. Opaline silica is often deposited in hot springs. Scientists proposed this area should be visited by the Mars Science Laboratory.
Going north of there we enter another region called Arabia Terra. Arabia Terra continues to the east into its own Region of the same name. For now we are only interested in the part that is in Oxia Palus.
Cliffs and canyons in Arabia Terra, as seen by HiRISE.
To the north we come to Becquerel Crater . Becquerel is a 167 km-diameter crater at 22.1°N, 352.0°E on Mars, in Arabia Terra. It is named after Antoine H. Becquerel. Photographs by the Mars Global Surveyor revealed layered sedimentary rocks in the crater. The layers appear to be only a few meters thick and show little variations in thickness. Recent studies with HiRISE have determined the exact thickness of the layers. The 66 layers measured showed one group of layers to average 3.6 meters (12 ft) and another group to average 36 meters (118 ft) in thickness. Patterns like this are usually produced on Earth through the effects of water; volcanic deposits would not produce ash or lava flows of such regular thickness and in any event there are no nearby volcanic vents.
Becquerel Crater
Layers in Becquerel Crater
There are cyclic variations in the thickness of the exposed sedimentary layers, possibly indicating cyclic variations in environmental conditions while the sediment was being laid down. Most of the layers are parallel to each other, suggesting they formed by vertical settling, but a few are cross-bedded, indicating that at the time that the layers were deposited the sediment was transported along the ground surface by wind or water. The sedimentary material appears to be easily eroded and active wind erosion may be continuing to the current day.
Central Uplift of Curie Crater
Curie Crater is an impact crater in the Oxia Palus Region of Mars, located at 29.1° N and 4.8° W. It is 114.1 km in diameter and was named after Pierre Curie, a French physicist-chemist (1859-1906).
Close-up of layers in central mound of Curie Crater, as seen by HiRISE.
The terraforming of Mars is the hypothetical process by which Martian climate, surface, and known properties would be deliberately changed with the goal of making large areas of the environment more hospitable to human habitation, thus making human colonization much safer and more sustainable. The concept relies on the assumption that the environment of a planet can be altered through artificial means. In addition, the feasibility of creating a planetary biosphere on Mars is undetermined. There are several proposed methods, some of which present prohibitive economic and natural resource costs, and others which may be currently technologically achievable. In many respects, Mars is the most Earth-like of all the other planets in the Solar System. Indeed, it is thought that Mars once did have a more Earth-like environment early in its history, with a thicker atmosphere and abundant water that was lost over the course of hundreds of millions of years. Given the foundations of similarity and proximity, Mars would make the most efficient and effective terraforming target in the Solar System.
The dream…..
No comments:
Post a Comment