These dark and mysterious formations on Mars, composed primarily of glass, which was formed during volcanic eruptions.
The area of these dark regions of more than 10 million square kilometers. They are located in the northern lowlands of Mars, but their exact composition is still not entirely clear. Spectral measurements have shown that they are different from other dark regions of the Red Planet, consisting mostly of basalt.
Briony Horgan and Jim Bell of Arizona State University in Tempe, analyzed the near-infrared region of the spectrum in this region with a rotating at low Mars orbit Mars Express. The nature of the absorption spectrum indicates a volcanic glass with impurities of iron - a brilliant substance resembling obsidian, which is formed when magma cools too quickly and minerals do not have time to go to a crystalline form.
Glass may take the form of grains with a grit size, as occurs in regions rich glass Iceland. Spectral analysis showed that the sand coated with quartz envelope.
On Earth, such shells around volcanic glass formed by water. But it remains to be seen how the glass grains are produced on Mars. Horgan believes that the scenario is quite likely Martian volcanoes interaction with water ice and snow. If so, this region is one of the best candidates for the search for life, because of the rich chemical elements of water - a key ingredient of life.