Subscribe free to our newsletters via your
. 24/7 Space News .




WATER WORLD
Ancient Earth Made Its Own Water - Geologically
by Staff Writers
San Francisco CA (SPX) Dec 23, 2014


Wendy Panero.

by Pam Frost Gorder A new study is helping to answer a longstanding question that has recently moved to the forefront of earth science: Did our planet make its own water through geologic processes, or did water come to us via icy comets from the far reaches of the solar system?

The answer is likely "both," according to researchers at The Ohio State University- and the same amount of water that currently fills the Pacific Ocean could be buried deep inside the planet right now.

At the American Geophysical Union (AGU) meeting they reported the discovery of a previously unknown geochemical pathway by which the Earth can sequester water in its interior for billions of years and still release small amounts to the surface via plate tectonics, feeding our oceans from within.

In trying to understand the formation of the early Earth, some researchers have suggested that the planet was dry and inhospitable to life until icy comets pelted the earth and deposited water on the surface.

Wendy Panero, associate professor of earth sciences at Ohio State, and doctoral student Jeff Pigott are pursuing a different hypothesis: that Earth was formed with entire oceans of water in its interior, and has been continuously supplying water to the surface via plate tectonics ever since.

Researchers have long accepted that the mantle contains some water, but how much water is a mystery. And, if some geological mechanism has been supplying water to the surface all this time, wouldn't the mantle have run out of water by now?

Because there's no way to directly study deep mantle rocks, Panero and Pigott are probing the question with high-pressure physics experiments and computer calculations.

"When we look into the origins of water on Earth, what we're really asking is, why are we so different than all the other planets?" Panero said.

"In this solar system, Earth is unique because we have liquid water on the surface. We're also the only planet with active plate tectonics. Maybe this water in the mantle is key to plate tectonics, and that's part of what makes Earth habitable."

Central to the study is the idea that rocks that appear dry to the human eye can actually contain water-in the form of hydrogen atoms trapped inside natural voids and crystal defects. Oxygen is plentiful in minerals, so when a mineral contains some hydrogen, certain chemical reactions can free the hydrogen to bond with the oxygen and make water.

Stray atoms of hydrogen could make up only a tiny fraction of mantle rock, the researchers explained. Given that the mantle is more than 80 percent of the planet's total volume, however, those stray atoms add up to a lot of potential water.

In a lab at Ohio State, the researchers compress different minerals that are common to the mantle and subject them to high pressures and temperatures using a diamond anvil cell-a device that squeezes a tiny sample of material between two diamonds and heats it with a laser-to simulate conditions in the deep Earth.

They examine how the minerals' crystal structures change as they are compressed, and use that information to gauge the minerals' relative capacities for storing hydrogen.

Then, they extend their experimental results using computer calculations to uncover the geochemical processes that would enable these minerals to rise through the mantle to the surface-a necessary condition for water to escape into the oceans.

In a paper now submitted to a peer-reviewed academic journal, they reported their recent tests of the mineral bridgmanite, a high-pressure form of olivine. While bridgmanite is the most abundant mineral in the lower mantle, they found that it contains too little hydrogen to play an important role in Earth's water supply.

Another research group recently found that ringwoodite, another form of olivine, does contain enough hydrogen to make it a good candidate for deep-earth water storage.

So Panero and Pigott focused their study on the depth where ringwoodite is found-a place 325-500 miles below the surface that researchers call the "transition zone"-as the most likely region that can hold a planet's worth of water. From there, the same convection of mantle rock that produces plate tectonics could carry the water to the surface.

One problem: If all the water in ringwoodite is continually drained to the surface via plate tectonics, how could the planet hold any in reserve?

For the research presented at AGU, Panero and Pigott performed new computer calculations of the geochemistry in the lowest portion of the mantle, some 500 miles deep and more. There, another mineral, garnet, emerged as a likely water-carrier-a go-between that could deliver some of the water from ringwoodite down into the otherwise dry lower mantle.

If this scenario is accurate, the Earth may today hold half as much water in its depths as is currently flowing in oceans on the surface, Panero said-an amount that would approximately equal the volume of the Pacific Ocean. This water is continuously cycled through the transition zone as a result of plate tectonics.

"One way to look at this research is that we're putting constraints on the amount of water that could be down there," Pigott added.

Panero called the complex relationship between plate tectonics and surface water "one of the great mysteries in the geosciences." But this new study supports researchers' growing suspicion that mantle convection somehow regulates the amount of water in the oceans. It also vastly expands the timeline for Earth's water cycle.

"If all of the Earth's water is on the surface, that gives us one interpretation of the water cycle, where we can think of water cycling from oceans into the atmosphere and into the groundwater over millions of years," she said. "But if mantle circulation is also part of the water cycle, the total cycle time for our planet's water has to be billions of years."


Thanks for being here;
We need your help. The SpaceDaily news network continues to grow but revenues have never been harder to maintain.

With the rise of Ad Blockers, and Facebook - our traditional revenue sources via quality network advertising continues to decline. And unlike so many other news sites, we don't have a paywall - with those annoying usernames and passwords.

Our news coverage takes time and effort to publish 365 days a year.

If you find our news sites informative and useful then please consider becoming a regular supporter or for now make a one off contribution.
SpaceDaily Contributor
$5 Billed Once


credit card or paypal
SpaceDaily Monthly Supporter
$5 Billed Monthly


paypal only


.


Related Links
Ohio State University
Water News - Science, Technology and Politics






Comment on this article via your Facebook, Yahoo, AOL, Hotmail login.

Share this article via these popular social media networks
del.icio.usdel.icio.us DiggDigg RedditReddit GoogleGoogle








WATER WORLD
Rosetta Reignites Debate on Earth's Oceans
Huntsville AL (SPX) Dec 18, 2014
Where did our planet get its oceans? Among planetary scientists, this is one of the most important and perplexing questions about the origins of Earth. One popular theory holds that water was brought to Earth by the ancient impacts of comets and asteroids. However, new data from the European Space Agency's Rosetta spacecraft indicate that terrestrial water did not come from comets like 67P/Chury ... read more


WATER WORLD
'Shooting the Moon' with Satellite Laser Ranging

Moon Express testing compact lunar lander at Kennedy

UK Plans to Drill Into Moon, Explore Feasibility of Manned Base

Carnegie Mellon Unveils Lunar Rover "Andy"

WATER WORLD
Tales from a Martian Rock

Russian scientists 'map' water vapor in Martian atmosphere

Flying over Becquerel

New idea for transporting spacecraft could ease trip to Mars

WATER WORLD
FFD signs Space Act Agreement with NASA for Space Suit Development

NASA Selects Commercial Space Partners for Collaborative Partnerships

Does the peer review process stifle scientific innovation?

NASA releases video of Orion spacecraft re-entry from astronaut's perspective

WATER WORLD
China's Long March puts satellite in orbit on 200th launch

Countdown to China's new space programs begins

China develops new rocket for manned moon mission: media

Service module of China's returned lunar orbiter reaches L2 point

WATER WORLD
Bright lights: big cities at night

NASA, SpaceX Update Launch of Fifth SpaceX Resupply Mission to ISS

Fifth SpaceX Mission Lets the CATS Out on the International Space Station

Politics no problem, say US and Russian spacefarers

WATER WORLD
SES: Astra 2G ready for Dec 28 Proton launch

Soyuz Installed at Baikonur, Expected to Launch Wednesday

Russian Space Agency Pushes Back Earth Imaging Satellite Launch to Friday

State Spaceports Receive Federal Funding

WATER WORLD
Kepler Proves It Can Still Find Planets

NASA's Kepler Reborn, Makes First Exoplanet Find of New Mission

Super-Earth spotted by ground-based telescope, a first

Astronomers spot Pluto-size objects swarming about young sun

WATER WORLD
Lead islands in a sea of graphene magnetize the material of the future

Theory details how 'hot' monomers affect thin-film formation

Penn Researchers Show Commonalities in How Different Glassy Materials Fail

Danish radars for new British offshore patrol boats




The content herein, unless otherwise known to be public domain, are Copyright 1995-2014 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement All images and articles appearing on Space Media Network have been edited or digitally altered in some way. Any requests to remove copyright material will be acted upon in a timely and appropriate manner. Any attempt to extort money from Space Media Network will be ignored and reported to Australian Law Enforcement Agencies as a potential case of financial fraud involving the use of a telephonic carriage device or postal service.