Part three of the three parts of the summary
glaciers
In 2007, the general picture of ice formations found in certain latitudes began to become clear. As on Earth, so also on Mars the climate is distinctly related to the latitudes. Although the presence of water ice at the poles is clear beyond a shadow of a doubt, as you move towards the equator you find more evidence of water ice. The ice shaped the surface not long ago. For example, formations of polygons are found near the poles that raise the possibility of contraction and expansion of the frozen ground, similar to those found in the Arctic and Antarctic regions on Earth. In the various flanks of the equatorial volcanoes there is evidence of large glaciers, similar to those found on Earth. There are also craters filled with fragments of glaciers and small valleys that "fall" into canyons. A phenomenon on Earth is strong evidence that glaciers filled and widened canyons. The obvious question is where did the glaciers go? A very large part of them evaporated and was deposited at the poles. The ice is very dominant in the middle latitudes only when the axis of Mars is tilted at a greater angle than today. The inclination angle can reach 45° (53).
The researchers were surprised by the discovery of glaciers in the equatorial region and they were probably formed millions of years ago during ice ages. When Mars was tilted on its axis and ice blocks covered large areas in medium latitudes. These glaciers were covered with a mantle of rock fragments that prevented them from evaporating. The hidden glaciers look like gentle slopes around the edges of steep hills(54).
The MRO discovered 5 new impact craters formed in the first half of 2008 that filled with ice. The craters are 3-4 meters in diameter and 0.5-2.5 meters deep. This discovery makes it possible to learn almost in real time about the exposure of soil material to the environment. Bright spots darkened during the first weeks of observations, as freshly exposed ice evaporated into the atmosphere. The evaporation of the ice occurred during the second half of 2008 (55).
ocean
According to measurements made by the Mars Global Surveyor spacecraft in 1996, 17 of 52 delta formations correspond to a sea line, raising the possibility of the past existence of an ocean in the northern hemisphere that covered 1/3 of the surface of Mars. The depth of the ocean was 600 meters. The ocean began to shrink continuously and gradually after reaching its maximum dimensions at the end of the Noahic period (56). Supporting evidence for this idea was also found in observations by the Odyssey spacecraft. A comparison was made regarding the presence of potassium, thorium and iron above and below what was perceived as an ocean coastline and the presence of these elements in an inner coastline (within the great ocean after it began to shrink) was also examined, which according to the researchers' assessment indicated a younger and smaller ocean. According to the findings of the observations, the places rich in these elements are below the boundaries of the young ocean and the older ocean compared to the entire region. These findings are consistent with other studies such as the transportation of volatiles and rocks to the northern plains and the creation of lakes and oceans in the northern plains including marine sediments that remained unburied and/or exposed by erosion and deformation. The size of the inner ocean is 10 times the size of the Mediterranean Sea and the larger ocean is 20 times larger than the Mediterranean Sea(57).
lakes
Holden Crater was probably once full of water, actually a lake. In the crater there are layers of sediments and on the peaks in breccia (consolidation of rock fragments). All layers contain minerals that form in the presence of water. This crater is located in an older basin called the Holden Basin. Before the formation of the crater, there were channels in the basin that deposited various sediments in the basin. At least 5% of the small sediments found in the upper layer of the large breccia are made of clays (58). Another lake is found in Eberswalde (17).
rivers
Many river formations have been found on Mars with clear signs that there was a lot of water flow in them, although it is difficult to determine how long the water flowed. One river was identified in the photographs, for which it can be determined that the duration of the flow was decades. In that place, the water burst out from under the ground to the surface and flooded the place with a force equal to the sudden eruption of the Mississippi River and has been flowing for 10 years. The flow was into a crater with a diameter of 128 km. In its flow, the water deposited many sediments at the bottom of the crater. According to various calculations, the water flowed at a rate of 2200-800,000 meters per second. The maximum flow duration was 90 years. For comparison, a flow rate of 800,000 cubic meters per second is 5 times greater than the flow rate of the Amazon River(59).
ice channels CO2
At the South Pole there are formations that have received the name "spider-like" (Araneiform). They have no equivalent on Earth and their width can reach 1.2 km. This is a seasonal phenomenon related to CO2. This gas partially condenses in the winter from the atmosphere and forms ice caps at the poles. In the spring the gas evaporates. It bursts out from the bottom of the domes, creates pressure and carves channels in the ground when it reaches the place where it evaporates back into the atmosphere. Usually these channels have a radial shape and the escape point of the gas is in the center of the formations. The depth of these channels is 1-2 meters (60,61).
Poles
On Earth the large ice sheets are mainly shaped by ice streams. On Mars, other forces shaped and are still shaping the ice caps. The North Pole is an accumulation of layers of ice and dust that are up to 3.2 km deep and cover an area the size of Texas. One of the prominent places in the Pole is the Chasma Boreale canyon, which is equal in dimensions to the largest canyon in the USA and is 2 km deep. It is believed to have been formed when volcanic heat heated the bottom of an ice sheet and caused a massive flood. According to another estimate, strong polar winds carved the canyon inside the ice cap.
Formations with a spiral structure reminiscent of D-Nor fireworks were also found. These grooves were first observed in 1972. Various explanations have been put forward as to the origin of these formations. What causes their formation and formation is the slow movement of the ice relative to more southerly polar ice sheets. also to be a part of it. The heat of the sun in some places caused ice to melt. These formations were formed over millions of years(62).
It turned out that the amount of 2 CO ice in the South Pole is 30 times greater than what was thought and based on this the researchers estimated that Mars was a wetter place than today and the atmosphere was denser in 2 CO, which allowed the existence of flowing bodies of water. The 2 CO ice reservoir on Mars is 4800 km/cubic (63).
minerals
1. Several places on Mars are rich in sulfate minerals formed by flowing water. One of the places where there are many sulfate deposits is a very large field of dunes in the North Pole that surrounds the polar ice cap. Among the dunes in which sulfates were found, the dark dunes have a large content of gypsum(64).
2. In the Tharsis area at E ° 246.4 – N ° 17 there is a crater containing minerals of silica olivine and pyroxene(65).
3. Chloride salts were found in 200 sites photographed by the Odyssey spacecraft in the southern hemisphere. On Mars these minerals are usually found in topographic depressions. These salts are evidence that in the places where they are found, there used to be large amounts of water that evaporated and left behind these minerals. These places were photographed again by the MRO spacecraft. In one of the photographs at E ° 225 – N ° 38.8 in Terra Sirenum you can see the cracks created in the ground with the drying of the salts(66).
4. The Mars Express and MRO spacecraft discovered clays of their kind in Vallis Mawrth found in low latitudes (41). In the Gale crater as mentioned earlier, Smectite minerals were found
from the clay group. In the Nili Fossae area, these minerals were also found, minerals that contain iron and magnesium that are formed during the passage of rock in liquid water(67). Also in the previously mentioned Holden crater there are clays and it is possible that they were formed before the impact of the meteorite that created this crater. At least 5% of the weight of the sediments in the upper layers of the megabreccias contain clays(58).
5. Hydrated silicate minerals known as Opal were found - minerals containing water. Such minerals are evidence of the location and duration of water inventions. This means that liquid water has existed on Mars for billions of years longer than previously thought. They are formed in places where minerals replace materials originating from volcanic activity or meteorite impact. Valles Marinaris is one of the places where this mineral was discovered. You see many places in the canyon where these minerals protrude, in thin layers along great distances around the edge of the canyon and sometimes also inside the canyon itself. The Spirit rover found this mineral in the Gusev crater. The mineral is common in relatively young areas. In several places the mineral has been observed together with iron sulfate minerals in or around dry channels. This finding indicates acidic water that remained on the ground for extended periods(68).
6. Finding carbonate minerals also indicates the presence of water in the past of Mars. The explosion of these minerals provides a lot of information regarding certain periods in the planet's past. Carbonate rocks are formed when water and CO2 come into contact with calcium, iron or magnesium in igneous rocks. CO2 from the atmosphere is trapped inside the rocks. Among the researchers there are those who estimate that Mars once had an atmosphere richer in 2 CO, which made it warmer and allowed the flowing water to be on the surface for extended periods. This water plowed through the ground and created the valleys that exist to this day. The problem with this approach is that the presence of these minerals is mainly regional and not global, so they cannot provide the amount of CO2 needed for a dense atmosphere.
One of the places where carbonates were found is in exposed layers around the Isidis basin which is 1489 km in diameter. and which was created 3.6 billion years ago. The most exposed rocks are found in Nili Fossae, which is 666 km long and is located at the edge of the basin. In this place there are rocks rich in olivine, a mineral that can interact with water and form carbonates. Carbonates were also found at the landing site of the Phoenix(69).
Lithosphere
A radar test showed that the boundary line between the ice layer and the ground beneath it is relatively smooth, which means that the Martian ground does not sink due to the weight of the ice cap. Therefore the lithosphere is thicker than thought. A number of conclusions are drawn from this, one derived from the other. As you go deeper into the ground, the temperature rises more gradually than expected, so the chances of there being liquid water at greater depths increase(70).
casing
Observations made back in the 70s by the Viking spacecraft showed that there are differences between the northern hemisphere and the southern hemisphere. The northern hemisphere is younger and its surface is flatter. The southern hemisphere is older and has many crushing levels. Measurements made 20 years later by the Mars Global Surveyor showed that the crust in the southern hemisphere is thicker and has more magnetic anomalies. Two explanations for these phenomena have been put forward. According to one explanation, an internal process that changed one half of Mars and according to the other explanation, the impact of a giant meteorite on one side of Mars was particularly strong. Strong enough to blow off some of the crust, but not strong enough to melt anything. The two explanations complement each other. Shock waves created during the impact move inside the planet to the point of causing changes in the magnetic field. In addition, the new crust created in the northern hemisphere, due to the melting of the mantle rocks during the impact, is different from the crust in the southern hemisphere(71).
The mantle of Mars is cooling at a rate of 40 - 30 C every billion years. Slower than the rate of cooling of the Earth's mantle C ° 100 – C ° 70 every billion years. Based on observations by the Odyssey spacecraft, maps of the explosions of several elements on the Martian soil were produced. The researchers mainly focused on silica, iron and thorium since they are sensitive to melting conditions. The explosion of these elements in the vicinity of 12 volcanoes indicates melting processes within the mantle in the last 4 billion years. Changes in the concentration of these elements in volcanic rocks are evidence of the drop in temperature over time in the mantle and thickening of the lithosphere where the melting occurs and of the trend that is created as one goes deeper. These findings make it possible to calculate the hominic development of Mars. The reason for the slow rate of humic change (in relation to the Earth) probably lies in the fact that Mars does not have plate tectonics(72).
The burning meteors in the atmosphere
The Global Surveyor Mars spacecraft discovered a meteor shower in the Martian atmosphere. This phenomenon occurred at an altitude of 80-95 km above the ground. Although the spacecraft could not directly observe the penetration of meteors into the Martian atmosphere and the ionization of the metals therein, the changes could be followed by monitoring the electron density in the atmosphere. To test this phenomenon, a model was developed that allows predicting the impact of dust in the atmosphere originating from Comet 79P/du Tait Hartely. According to this model, 6 meteor showers were identified. Two such showers, one in April 2003 and the other in March 2005, were analyzed. According to an estimate, the size of the dust grains from the 2003 shower was 1 millimeter. The size of the dust grains of the second shower was 5 millimeters. The last ones burned deeper in the atmosphere (73).
resemblance to the earth
In a geological study conducted in July 2006 in Alaska, formations were found that resembled photographs of Mars taken by the Viking spacecraft in the 70s. Formations that look like a triangle were found in one of the glaciers and were named fans. The surprise was that the conditions on Mars are different from those prevailing on Earth. During the same study in Alaska, 289 events involving rockslides and floods were found. Most of them were avalanches of snow and ice. The assessment was that the origin of these events was climatic changes. As the temperatures rise, the glaciers are retreating and the ice is cracking in many places. In these places, a lot of material falls and creates the avalanches, which is probably also what happens on Mars. This estimate was confirmed by the high-resolution MRO images. To the researchers' surprise, this spacecraft photographed this phenomenon while it was happening. Blocks of ice, dust and probably rocks also deteriorated along slopes and large amounts of dust rose into the air. The size of the dust cloud was 180 meters. What caused this phenomenon on Mars is still unclear. It is possible that the heating of the ice layer by the sun caused this(74).
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