Back in 2006, MARSIS radar revealed beneath the surface of the planet vast accumulation of water ice - and not only at the poles. In particular, the ice-filled crater with a diameter of about 250 kilometers, located under the plain of Chryse. And the year before that experts from Germany found on the slopes of a Martian canyon, located in the region of Melas Chasma, tracks, similar to the riverbed channels, which were at the bottom of sulfate compounds are usually formed as a result of oxidation by water. This led to the conclusion that there was once a vast sea.
Scientists believe that over a period of water on Mars, there was not only frozen, but in the liquid state. Volcanoes melt ice beneath the surface, and the water flowed out. After a while she began to evaporate, as evidenced by the discovery of the planet Connection sulfates.
Last year, the rover Curiosity handed obtained by telemetry pictures in which rocks of Mars can see something resembling a gravel strewn bed of the river or stream. The photos were taken in the area of Gale Crater, a crater is clearly visible the deeper layers of the Martian soil that can tell us about the geological history of the Red Planet. Found riverbed located between the field to the north of the crater and the foot of acute mountain. According to experts, the size and shape of the riverbed stones can get an idea of what was the length of the river and the current rate of water in it.
According to most scientists, the water on the red planet still present. However, it is not clear why in the lowlands of the northern hemisphere occurs, compared with the south, so little phyllosilicates - minerals rocks, which are usually formed on the bottom of water bodies.
Recently able to clarify this issue. Construction of the climatic and geochemical models of Mars has shown that, if there was the ocean on the planet, part of its surface was covered with ice. In addition, the details of the relief on the edges of the proposed ocean basin correspond to the presence in the area of large glaciers. The researchers believe that it is low temperature and prevent the formation of ice cover on the bottom of the reservoir layer silicates typical of marine sediments.
All these facts indicate that the previously constructed models of the formation of the Martian climate did not accurately reflect the real picture. While some models are of ancient Mars dry and cold, and others - warm and humid, in fact, the Earth#39;s climate in the distant era, most likely it was wet and very cold, close to the circumpolar on Earth. This is consistent with all the newly discovered geological features.
At this time, researchers are interested in the region called Aeolian ridge, which is a plain, located on the border between the northern lowlands and southern highlands. It is covered by a number of mountain ranges, which scientists interpret the ancient river beds.
These formations are raised above the surrounding terrain, and not drowned, as is usual with beds of water bodies as coarse sand and gravel in them more resistant to erosion than the fine earth in place of the floodplain - so the experts explain this phenomenon.
Dibayes and his colleagues studied the area from the images taken by the camera HiRISE spacecraft Mars Reconnaissance Orbiter. Due to the very high resolution, using the device can see objects as small as 25 centimeters. Also, some places specially photographed at a slight offset in order to obtain three-dimensional images.
As it turned out, the channel alleged Martian rivers gradually expand, and then running down steeply, forming a delta - sedimentary deposits that are typical of the confluence of the rivers into lakes, seas or oceans.
On Mars, and previously revealed the formation, similar to the delta, but they all lie within a distinct topographical boundaries - for example, impact craters. While this time is in the delta region is unlocked. This can be more than an indication that the planet was once covered the ocean - there and fell into the river ...
