Ancient volcanic rocks were eroded and stored a sea's worth of water in Earth's crust as they became buried. (Image credit: James O'Neil via Getty Images)
Porous rock that formed during one of Earth's biggest volcanic eruptions absorbed so much water as it eroded that it created a huge reservoir over the eons, now buried deep in Earth's crust.
A massive water reservoir is hidden deep beneath the ocean floor off the coast of New Zealand — and it may explain why the region experiences slow-motion earthquakes, scientists have found.
A sea's worth of water became locked inside volcanic rocks that formed 120 million to 125 million years ago during the early Cretaceous, when a lava plume the size of the U.S. burst through Earth's crust and solidified into a vast plateau, researchers said in a statement. Thick layers of sediment have since blanketed these rocks and buried any trace of their explosive past 2 miles (3 kilometers) below the Pacific Ocean seabed.
The researchers mapped a fault line along the east coast of New Zealand's North Island and found that these ancient rocks were abnormally "wet," with water making up nearly half the volume of cores drilled up from the ocean floor.
"Normal ocean crust, once it gets to be about seven or 10 million years old, should contain much less water," study lead author Andrew Gase, a marine geophysicist and seismologist who conducted the research while at the University of Texas Institute for Geophysics (UTIG), said in the statement.
Shallow seas that surrounded the ancient volcanic plateau may have eroded the rocks into a porous honeycomb, which sponged up water and stored it like an aquifer, according to the statement. This water-logged terrain slowly transformed over the eons, absorbing more water as the rocks were ground into clay and became buried. READ MORE...
