Scientists used to think our planet’s water arrived on Earth after comet collisions deposited ice. But a new study reveals that liquid so vital for life may have originated on Earth after all. Research led by University College Dublin shows chemical reactions between fluid hydrogen and silicon dioxide deep down in Earth’s mantle could create water.
At high temperatures and pressures, fluid hydrogen and silicon dioxide in quartz can react to form liquid water, scientists discovered. They ran computer simulations, checking different temperatures and pressures similar to those found in the upper mantle 25 to nearly 250 miles below Earth’s surface. When fluid hydrogen and silicon dioxide are exposed to a pressure 20,000 times greater than the atmospheric pressure on Earth, and a temperature of around 2,552 degrees Fahrenheit, the two substances can produce water.
Scientists thought water resulting from the chemical reaction would form on the quartz’s surface. But the water was instead trapped inside the quartz, building up pressure. The scientists think when this pressure is released, it could result in earthquakes under the Earth’s surface.
The journal Earth and Planetary Science Letters published the study online in January. Along with two scientists from University College Dublin, three other researchers from Canada’s University of Saskatchewan and China’s Jilin University collaborated on the paper. Their findings lend further credence to Japanese 2014 experiments on fluid hydrogen and silicon dioxide.
Paper co-author Niall English of University College Dublin said, “We were initially surprised to see in-rock reactions, but we then realized that we had explained the puzzling mechanism at the base of earlier Japanese experimental work finding water formation. We concluded that these findings help to rationalize, in vivid detail, the in-mantle genesis of water. This is very exciting and in accord with very recent findings of an ‘ocean’s worth’ of water in the Earth’s mantle.”