According to the findings of planetologists from the University of California at Berkeley, published in the journal Nature, the first oceans on Mars appeared about 4 billion years ago and 200-300 million years earlier than was commonly believed.
“Scientists have always believed that the plateau of Tarsida, the largest volcanic form of relief on Mars, arose before the oceans of Mars were born, about 3.7 billion years ago. We found out that the oceans either originated with him, or appeared even earlier, “commented Michael Manga, a geologist at the University of California, Berkeley.
In recent years of active exploration of the Red Planet, planetologists have discovered many hints that on ancient Mars there were rivers, lakes and even entire oceans from the water, containing almost as much liquid as our terrestrial Arctic Ocean. With these conclusions, however, not all agree. Some scientists believe that even in ancient times Mars could be too cold for the constant existence of the oceans, and if water existed in liquid form on the planet, then only at the time of volcanic eruptions.
Recent observations of Mars with ground-based telescopes showed that for the past 3.7 billion years, Mars has lost so much water that it would be enough to cover the entire surface of the ocean with a thickness of 140 meters. Where did this water go? The scientists still do not know the answer, so today they are trying to figure it out by studying the ancient Martian meteorites that landed on Earth.
While studying the structure of the shoreline of the supposed ocean of the Red Planet, which covered most of its northern hemisphere in the distant past, Manga and colleagues, that the oceans appeared on Mars 200-300 million years earlier than was stated in the conclusions of earlier scientific studies.
Mars now (left) and how he could look in the past (right)
According to Mang, many planetologists doubt it in the very existence of this structure, since the parts of the bottom of this ocean are located in “wrong” places, where the water had to flow from below upwards to cover its entire area. In addition, regions that look too deep and others on the contrary are too small to doubt are too small to constitute a single body of water with a total water level.
California geologists found an explanation for this by analyzing how the formation of the volcanic plateau of Tharsis could have influenced on the birth and evolution of the Martian oceans, and also drawing attention to a newly discovered fact associated with this largest geological structure of Mars.
Exploring the plateau and the adjacent northern plains where the positively once was an ocean of Mars, scientists have noticed that many of the relief features associated with its coastline, looked older than she Tharsis and related volcanoes. This led them to the idea that this structure was born not before, but after the formation of the oceans of Mars.
Guided by this idea, scientists compared how the shoreline of these reservoirs changed, with the rapid growth of Tarsida for about half a billion years after its formation. This comparison surprisingly showed that virtually all the distortions and strangeness in the shoreline were related to how the ocean floor was deformed under the influence of growing volcanoes.
By eliminating all these factors, scientists discovered that the Arabian Plain of Mars, which is the oldest part the bottom of its oceans, arose even before the formation of Tarsida, hundreds of millions of years before the supposed time of the appearance of the oceans of the Red Planet.
Calculations showed that the Arabian Ocean contained about three percent of the total EMA of the water contained in the oceans on Earth. In other words, it was about twice as large as the modern Arctic Ocean, and contained more water than the polar caps of the Earth. Scientists believe that it became liquid due to the warmth and greenhouse gases that volcanoes developed, including the future Tarsida.
In subsequent epochs, the area and volume of this reservoir constantly changed as the Tarsida grew, which gave rise to strange features in the shoreline the northern ocean of Mars and made it much deeper than it was originally. Scientists hope that the seismographs of the new Insight landing module, which will go to Mars in May, will help verify their theory.