Water has long been seen as an external factor that molds the Earth's outer layer. Yet, recent research indicates it plays a vital role far beneath the Earth's crust. These studies show that there's a lot of water, up to 620 miles (1,000 kilometers) deep within the Earth's mantle.
Water's Role in Geological Activity
Water isn't only crucial for life on Earth's surface and a major player in the geological processes that shape our planet. Dr. Mainak Mookherjee, the leader of one of the studies, clarifies that the presence of water deep within the Earth is essential for mantle convection. This process entails the transfer of solid rocks from hotter to cooler areas over very long periods of time. Without water, this mantle convection would become ineffective and eventually come to a halt.
Dr. Mookherjee also points out the link between mantle convection and volcanic eruptions. Mantle convection manifests itself through the movement of tectonic plates, which are the driving forces behind the birth of volcanoes. These volcanoes, in a way, are responsible for crafting the Earth's surface where we live. If there were no volcanic activity, the formation of the Earth's outer layer would come to a standstill, and essential planetary processes would come to a halt.
The concept of water existing deep within the Earth was initially put forth in 2014. Back then, scientists discovered signs of water in diamond pieces originating from the Earth's mantle. These diamonds hold tiny bits of minerals that took shape hundreds of kilometers beneath the surface, providing a glimpse into the Earth's otherwise unreachable inner layers. This water isn't in its liquid state; instead, it's made up of hydrogen and oxygen atoms within the crystal structure of the minerals, which, as we know, form the building blocks of water.
Earth's Crust, Water, and The "Transition Zone"
Scientists have pinpointed an area known as the "transition zone," located between 410 and 660 kilometers beneath the Earth's surface, as the vital spot for these water-absorbing minerals. This region falls between the upper and lower layers of the Earth's mantle. The minerals, like wadsleyite and ringwoodite, have the ability to trap water and then release it as they undergo melting.
Tests indicate that minerals found in the transition zone, like wadsleyite and ringwoodite, can retain substantial water content, perhaps amounting to 1 to 3 percent of their own weight. When you take into account the significant width of the transition zone and the Earth's overall mass, it's feasible that this zone holds several times the amount of water found in all the world's oceans.
Seismic data has shown the existence of minerals that could hold water, hinting at the possibility of an extensive underground water reservoir. In a particular study, researchers discovered diamonds containing actual water ice trapped within them, proving that water exists at even greater depths than previously thought.
So, the big question is, how did this huge stash of water wind up below us? The old story goes like this: Earth got its water from celestial objects packed with water, such as asteroids and comets. But if there truly is a colossal water supply in the transition zone, this idea gets shaken up. Some theories suggest that water might have clung to dust particles during Earth's birth, implying that at least a portion of the inner water has been around since the start.
Unlocking the Mysteries Beneath Earth's Crust
These discoveries are certainly intriguing, yet there's still a lot left to uncover. Researchers are actively delving into the characteristics and scope of water in the Earth's mantle. The potential to gauge the electrical conductivity of the mantle offers hope, and the discovery of additional diamonds with water-containing minerals could offer additional glimpses into the Earth's concealed water supplies.
The revelation of substantial water reserves deep within the Earth's mantle reshapes our comprehension of the planet's geological mechanisms. This concealed water supply highlights the intricate connection between surface phenomena like volcanic eruptions and the dynamic forces beneath us, adding an extra layer of intrigue and enigma to the world of Earth's geology.