Earth's hidden water reserves: Unveiling the power of superhydrated crystals
The planet's oceanic crust holds a secret: a common clay known as talc, which can transform into a superhydrated crystal, capable of storing an astonishing 31% water by weight. This remarkable discovery, made by a team of scientists from South Korea, Germany, and the United States, reveals a new way water can be transported deep underground, potentially reshaping our understanding of Earth's water cycle.
In a groundbreaking study, researchers found that talc, when exposed to specific conditions, undergoes a phase change, expanding by 60% and trapping water between its layers. This transformation occurs at depths ranging from 56 to 78 miles in cold subduction zones, where the water content reaches approximately 31%.
The key to this discovery lies in the atomic scale, where distances are measured in angstroms, one-ten-billionth of a meter. Scientists identified a 15 angstrom phase, stable at depths of 56 to 78 miles, and a 10 angstrom phase, which emerges at greater depths. This phase shift indicates the mineral's ability to store and release water, a process influenced by the presence of salt and mild alkalinity.
The research, led by Dr. Yoonah Bang of Yonsei University, highlights the importance of mineral reactions under high pressure, which play a crucial role in moving water into Earth's interior. By studying these reactions, scientists can better understand the distribution of water at various depths, a factor that significantly impacts rock melting points and fault weaknesses.
The study's findings have far-reaching implications for earthquake science. The release of water from sinking plates contributes to magma formation, and the 15 angstrom phase's water storage capacity could influence the location of melting points. This, in turn, may affect the occurrence of earthquakes in specific regions.
Field geologists and geophysicists now have a new tool to explore. They can search for ancient rocks with 15 angstrom spacing and smectite-like swelling behavior, indicating the presence of extra water. This discovery encourages future models to consider fluid chemistry, rather than just pressure and temperature, in their analysis of Earth's deep water cycle.
The research, published in Nature Communications, opens up exciting possibilities for understanding Earth's water distribution and its impact on geological processes. As scientists continue to explore these hidden water reserves, we may uncover more secrets about our planet's inner workings.
