Multiple Oceans Of Water May
Be Deep Underground On Earth

By Charles Choi in New York

TOKYO (UPI) - A new report from Japan Thursday reveals a vast amount of water -- up to five times or more than in the oceans -- may hide in the molten layers of rock near the Earth's core.

While this deep water would be locked away in crystal lattices instead of pooling in giant underground seas, as in Jules Verne's "Journey to the Center of the Earth," this incredible reservoir may still help shake the foundations we stand on, making rock melt much easier and flow significantly quicker.

"The presence of water in a crystal structure could reduce the strength of a mineral," explained lead researcher Motohiko Murakami and his colleagues at the Tokyo Institute of Technology in the journal Science. The rock around the core could therefore be "considerably softened."

These findings may also explain how iridescent crystals made their way into unusual diamonds ejected from volcanoes in Brazil.

"They're sort of a peacock color in the diamonds -- quite pretty, actually," said diamond geologist Mark Hutchison at the Australian National University in Canberra.

Geologists believe when Earth originally formed from dust, it should have contained 100 times more water than now found in the oceans. While a great deal of that may have boiled away into space early on, scientists also suspect some of it may still lie hidden deep in Earth's interior.

Earth is split up into three distinct layers -- the thin, fractured outer crust some 20 miles deep, the inner metal core roughly 4,300 miles wide and the hot rock of the mantle in-between, about 1,800 miles thick.

For years, scientists have known water gets sucked from the oceans down the cracks in the crust into the upper, shallow layers of the mantle, where it lowers melting points and helps liquefy rock, aiding in the birth of volcanic eruptions.

"Water is certainly being taken down -- the question is once you get deeper in the mantle, is the water forced upwards or does it get accommodated in the minerals of the lower mantle?" Hutchison said. "And the answer here is that it can."

The investigators synthesized materials normally found only in the high temperatures and high pressures near the Earth's core, such as silicate crystals called perovskites and a black cubic mineral known as magnesiowustite. Surprisingly, they could absorb up to two-thousandths their weight in water -- an amount counting for five times the world's oceans.

There may be even twice that amount of water or more, if evidence from iridescent perovskite crystals in Brazilian diamonds Hutchison found is right. The team in Japan discovered aluminum helped perovskite absorb more water. Hutchison believes his diamonds are from the lower mantle, and the gems indicate aluminum levels are higher near the center of the Earth than the Japanese researchers estimated.

Hutchison commented that while all these results say water can be down there, "they don't answer the question if water is actually down there. But now that we have an idea of what the maximum amounts may be, then we can go back and tackle the question using mathematical modeling."

He explained that water at that depth could make the flow of rock -- which affects global activity -- significantly more rapid.

Copyright © 2002 United Press International. All rights reserved.

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