Mars today is a dry, frozen world but it once had water flowing across its surface.
Previous researches have suggested that water on Mars surface was lost to space as a result of deteriorated magnetic field. Solar wind and radiation stripped away the Martian atmosphere and transformed it from a planet that might have supported life on its surface to a hostile world we know today. However, this theory does not explain where all of the Mars water has gone.
Now, researchers from Oxford's Department of Earth Sciences have proposed another explanation for the event. They suggest that Martian surface may have absorbed the water of the planet.
Using modeling methods, researchers calculated how much water could be removed from the Martian surface through reactions with rock. They found that basalt rocks on Mars can hold approximately 25% more water than those on Earth. This is likely the reason why we do not see water on Mars at the present time.
"People have thought about this question for a long time, but never tested the theory of the water being absorbed as a result of simple rock reactions. There are pockets of evidence that together, leads us to believe that a different reaction is needed to oxidise the Martian mantle. For instance, Martian meteorites are chemically reduced compared to the surface rocks, and compositionally look very different. One reason for this, and why Mars lost all of its water, could be in its mineralogy.” Lead researcher Dr Jon Wade from Oxford's Department of Earth Sciences said in a statement.
Mars and Earth are similar in many ways, but they are very different when it comes to temperature and geological chemistry. Mars has higher iron content on its mantle rocks than Earth and these subtle changes can cause dramatic differences. As a result, Earth never experiences conditions similar to Mars'.
“The Earth's current system of plate tectonics prevents drastic changes in surface water levels, with wet rocks efficiently dehydrating before they enter the Earth's relatively dry mantle,” said Dr Wade. “But neither early Earth nor Mars had this system of recycling water. On Mars, (water reacting with the freshly erupted lavas' that form its basaltic crust, resulted in a sponge-like effect. The planet's water then reacted with the rocks to form a variety of water bearing minerals. This water-rock reaction changed the rock mineralogy and caused the planetary surface to dry and become inhospitable to life."
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