Mineralogists found in terrestrial diamonds "alien" ice
The collected and studied diamonds from deposits in South Africa, China, Zaire and Sierra Leone, scientists from the University of Nevada (USA) have discovered microscopic inclusions very rare ice cube-shaped. Such ice is called ice-VII. This finding may lead to a reassessment of our understanding of the amount of water hidden in the bowels of the Earth, the researchers comment in a published article in the journal Science.
The researchers note that almost all of the ice, with which we deal in everyday life, for example, from the same refrigerator, presented in the form of ice-Ih having a hexagonal crystal lattice. In general, several tens of science known other phases of ice, which can be formed at various exotic conditions. These include and ice-VII, having a cubic crystal lattice. As a rule, it occurs in the open space, but on earth it managed to get only under laboratory conditions, at extremely high temperatures and pressure. Nevertheless the team of mineralogists from Nevada University under the direction of Oliver Zauner has found the first samples of natural ice-VII. Scientists believe that the formation of crystals occurs at depths of 610-800 kilometers, where, as previously thought, there is no presence of water. Thus, to explain his presence there can only be the fact that the inclusion of water could sink deeper under the surface, and growing with the temperature and the pressure eventually led to the formation of ice-VII.
This area is on the border of the transition between the upper and lower mantle of the Earth, as well as a little deeper it. While it is difficult to say how much water there may be contained, but its very presence will force geologists to revise the energy balance of the mantle and the processes developing in its rocks.