Earth scientists from among others Utrecht University and the Free University of Berlin have found new clues how water moves inside the Earth’s deep subsurface layers and ultimately back to the surface through volcanic activity. They published their results in the journal Nature Geoscience on 26 December 2016.
Two water cycles
Planet Earth has two water cycles. The first one involves our oceans, with cloud formation through evaporation resulting in rain on land and ultimately drainage back to the ocean, often through rivers. However, in the deep hidden layers of the Earth there is another cycle and up to this point the water flow of this second cycle was poorly understood.
Plates take water along
Within the Earth’s tectonic plates water molecules are trapped into the rock forming minerals of various chemical compositions. In areas where the plates collide one plate moves underneath the other one and sinks down into the mantle taking along the water molecules inside it. Without a chemical and physical mechanism whereby water gets returned to the Earth’s surface it is estimated that the oceans would get depleted in potentially 1.5 billion years. But as we can observe everyday this doesn’t happen.
An interdisciplinary team of scientists studied ancient rocks found in Italy in a quest to further understand Earth’s second inner water cycle.