Scientists have now discovered solid evidence to support what they had long assumed – that water is present in abundance, deep within the earth’s crust.
The finding of a small fragment of a rare mineral that has previously only been found in meteorites has led them to the conclusion that there exists a vast reservoir of water underground, with more water than all the earth’s surface oceans put together. (Read: Giant Virus in Siberia discovered by scientists)
It is believed, after analyzing seismic data, that minerals with sponge-like characteristics exists in the mantle and hold water. Unfortunately, they are too deep within to be reached with modern drilling equipment. However, the discovery of a ‘brown diamond’, a form of rock with water inside, has led to the concretization of these assumptions.
The rock had been brought to the earth’s surface by a volcanic eruption, from deep inside it, and then fished out of a Brazilian riverbed. After years of study, it was eventually recognized as ‘ringwoodite’ – a mineral that forms with a common mineral in the earth, olivine, is subjected to extremely high pressures. It was the first time this mineral was found in the earth, and from its depths.
Ringwoodite had only been found in meteorites before, due to impact on the earth. Scientists have also found that this mineral can form and remain stable in the transition zone between the upper and lower mantle. Currently there is no method to gain more samples of it, however.
What was more remarkable was that on analysis, the rock showed that roughly 1.5 percent of its weight was water, which was locked into the mineral at the time of formation. This water could only exist if it were abundant in the Earth’s mantle, where the mineral currently is. The total volume of the transition zone indicates that the proportionate concentration of ringwoodite, and subsequently that of that water would be huge.
It is to be noted that one sample of ringwoodite is too small to be analysed sufficiently by scientists. There is need for more such samples, though the sheer depth of the water would make it impossible to extract.
Knowing where the water is concentrated and to what degree can help in the understanding of plate tectonics. The earth’s crust is broken into moving plates, as a result of the heat from its core. This water is believed to lubricate the tectonic plates, making movements easier and facilitating earthquakes and tsunamis. Also, when water is infused into magma, it makes the resultant volcanic eruptions more violent.