Ringwoodite

Geologists have discovered a massive reservoir of water underneath the Earth’s surface. The volume of the water inside is approximated to be three times the volume of all the oceans.

The mineral, ringwoodite, is known for being able to preserve water within its structure (not as a liquid, but in the form of hydroxide ions) and that’s where the geologists discovered the massive amounts of water thousands of kilometers below the Earth’s surface. Earlier research on ringwoodite sample also confirmed the existence of huge quantities of water in the Earth’s mantle.

Ringwoodite is a high-pressure polymorph of olivine that exists abundantly in the transition zone, it extends a depth of 410 km to 660 km inside the Earth’s mantle.

The discovery makes us hypothecate that oceans gradually came out of the interior of the earth millions of years ago, but some geologists think ocean was formed when some water-laden asteroids struck the planet.

Read: Water-laden Asteroids Discovered

  • Reference: Science
  • Image: University Of Alberta

23 thoughts on “Ocean Discovered Inside Earth’s Mantle

  1. Earth and space sciences seem to be in a bit of a state of flux; which is not terribly surprising. I can’t help feeling that if the oceans, etc., had seeped out from this layer, they’d still be seeping. So I tend to go for the asteroid thesis … I suppose … unwillingly …

    1. Yep, oozing out from down below is the alternate assumption of where ocean actually came from. However, the fact is it’s just a molten rock filled with water (which can be separated at a certain temperature). This is what the paper says:

      The high water storage capacity of minerals in Earth’s mantle transition zone (410- to 660-kilometer depth) implies the possibility of a deep H2O reservoir, which could cause dehydration melting of vertically flowing mantle. We examined the effects of downwelling from the transition zone into the lower mantle with high-pressure laboratory experiments, numerical modeling, and seismic P-to-S conversions recorded by a dense seismic array in North America. In experiments, the transition of hydrous ringwoodite to perovskite and (Mg,Fe)O produces intergranular melt. Detections of abrupt decreases in seismic velocity where downwelling mantle is inferred are consistent with partial melt below 660 kilometers. These results suggest hydration of a large region of the transition zone and that dehydration melting may act to trap H2O in the transition zone.

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