This lowland could resemble the Arctic polar region in the world, filled by means of the ocean. But dry Mars at least 3.5 billion years. Only the wind drives the dust on its surface scarred by meteorites. Could Mars be different in the past? Is there lapped the ocean? If swept from the slopes of wild rivers? To understand this, scientists have carefully studied the material, which is filled with plain – formation Vastitas Borealis. Not an easy task. And on earth geologists sometimes cannot figure out the origin of a portion of the earth’s crust. Mars is that task becomes challenging quests requiring launch of spacecraft and robotic planetary rovers with precision instruments.
In the 1980s, the orbital and landers project Viking Transfer pictures of the Martian surface. By studying these images, a geologist Timothy Parker Timothy Parker and his colleagues at the California Institute of Technology saw the contact area of land and sea around the northern plains. He hypothesized that Vastitas Borealis – a relic of the ancient ocean and outlined its contours. An article about this, he published in 1989.
The hypothesis of an ancient Martian ocean in the north became popular, scientists from dissimilar countries to take her test. But still an open question and the origin of the formation Vastitas Borealis is no consensus. For an explanation of Scientific Russia appealed to the senior researcher, Laboratory of Comparative Planetology Vernadsky Institute Mikhail Ivanov, who is studying the geology of this area of Mars? Now he is on a business trip at the Institute of Planetology at University of Münster in Münster (Germany).
The fact that the ocean is important to test the hypothesis of the investigation the contact between the formation Vastitas Borealis and the southern mainland must be on the same hypsometric level, if it is a shoreline of an antique ocean, said Mikhail Tarkovsky. Such a check was made after receiving the first data precision laser altimeter on board the orbiter MOLA Mars Global Surveyor. Measuring the height of the contact at different locations showed that it really is about the same level, which is consistent with the hypothesis of the ocean. However, the contact is not forever at the same height and this gives rise to many researchers to doubt the correctness of the hypothesis Parker.
In favor of the hypothesis of the ocean are called channels ending. These gigantic structures on the surface of Mars, which were formed due to the large flows of water. The thickness of the channels is hundreds of kilometers length – thousands. Their water origin was known long before Parker’s hypothesis. These channels are the same age with the formation Vastitas Borealis and she even gets in their end. Channels expiration could easily go huge amounts of water, which would be enough to fill the lowlands.
Just imagine the Martian ocean, by analogy with the Earth’s oceans would be wrong, said Mikhail Ivanov. He looked totally different if it ever was. Catastrophic discharge of water from the south through the channels filled valley. Detrital material posed in the lowlands of the northern plains, deposited on the bottom. According to the scientist, it was a huge, dirty pool. Sources of water for her were likely to channels expiration, which, in contrast to terrestrial rivers are simply short-ducts are not related to the very water circulation in natural world, which nourishes our rivers. All of this could have happened about 3.5 billion years ago – in rannegesperiyskuyu era, according to geochronology of Mars. Atmospheric conditions on the planet then, apparently, were the same as it is now, so the water cannot long remain in liquid form, it freezes and then evaporates. Existed ocean-pool for long – tens or hundreds of thousands of years and then dried.
Contacts, mapped Parker, now do not look reliable evidence of the ancient shoreline location. Some of them were clearly of volcanic origin; some do not converge in height. But the lack of coastline does not mean that the water in the Great Northern Plains were not. There is other evidence and they are in formation Vastitas Borealis. Scientists are studying the different parts of its structure, which can be interpreted as having a water origin. These cones left mud volcanoes, and polygonal structure and traces of water flows.
Just signs of water mud flows found in Utopia Planitia and Atsidalii Mikhail Ivanov of the Institute of Geochemistry and Analytical Chemistry. Vernadsky, RAS and colleagues. These plains are depressions in the territory of the northern Vastitas Borealis. If there existed an ocean, then Utopia and Atsidaliya would be the deepest reservoirs. Therefore, if and where traces of water period Vastitas Borealis, then they need to look at Utopia and Atsidalii. Atsidaliya, moreover, directly adjacent to the mouths of the channels discharge, and water from the first channel should be accumulated in this region. Utopia is removed from the channel and could be isolated area, said Mikhail Ivanov. It remains unclear whether they existed or were separated single dirty puddle. Given that mud flows about the same age are in both areas it is weighty reinforcement hypothesis of a single ocean. Article with the results of this discovery, published in the December 2014 Journal of Icarus.
Another argument in favor of the participation of water in the formation of rocks Vastitas Borealis – clay layers in Atsidalii, which are described in Mark Salvatore and Philip Christensen from the University of Arizona, recently published in the journal of Geophysical Research – Planets. The researchers found layers of clay from the spectral data on the walls of impact craters. Earth on Mars – this is a very significant indicator of the fact that there was water, because without it, it could not be shaped, or rather its constituent minerals. Earth layers can be traced over a large area of hundreds of square kilometers due to impact craters that penetrate the surface. According to Mikhail Ivanov, impact craters on Mars – a kind of natural boreholes reveals what lies beneath the surface. And if there is a clay horizon of such area, then for his education had to be a lot of water. It turns out that, at least in Atsidalii could exist Sea and open Ivanov mudslides fit well with this hypothesis.
The international project to study the formation Vastitas Borealis, which involved Mikhail Ivanov, supports Deutsche Forschungsgemeinschaft. In the future, the project will be continued and scientists will be engaged in detailed mapping of the boundaries of the northern wastes.
Open questions remain, where did a huge amount of water on Mars, to fill the northern lowlands and then where has it gone? Back in 2003, Michael Carr of the US Geological Survey and James Head from Brown University calculated that education Vastitas Borealis would require 2,3×107 cubic kilometers of water. They believe that part of this volume is stored in ice polar caps of Mars, Part vanished into space and another part – no one knows where. But Tim Parker seems to have found the missing water. Last year, he suggested that the relic ocean still exists in the Great Northern Plains, but we do not see it because it lies beneath the surface in the form of ice horizon.