Origins of Earth Water Contemporary With the Blue Planet’s Formation

Summary: The origins of Earth water contemporize with the Blue Planet's formation 4.5 billion years ago, according to study in published in Science Nov. 13, 2015.

Scanning electron microscope images of Baffin Island rock samples with olivine mineral grains (A) and trapped pockets of glass, known as melt inclusions (B), containing tiny amounts of water sourced from mantle plume: "Researchers shed new light on the origins of Earth's water.": The SETI Institute @SETIInstitute via Twitter Nov. 13, 2015

The origins of Earth water are contemporary with the Blue Planet’s formation 4.5 billion years ago, according to a study published online Nov. 13, 2015, in the journal Science.

As lead researcher, lead writer and Marie Curie Research Fellow at the University of Glasgow in Scotland, Dr. Lydia Hallis and five co-authors and co-researchers base their findings upon basaltic rocks collected in Canada from Baffin Island in 1985 and examined during a UHNAI (University of Hawaii National Aeronautics and Space Administration Astrobiology Institute) postdoctoral fellowship.

The Baffin Island picrite contains tiny amounts of water in small pockets of glassy melt within cracked grains of the mineral olivine. Advanced ion-microprobe instrumentation detects the rock’s deep mantle components.

Dr. Hallis explains: “On their way to the surface, these rocks were never affected by sedimentary input from crustal rocks, and previous research shows their source region has remained untouched since Earth’s formation. Essentially, they are some of the most primitive rocks we’ve ever found on Earth’s surface, and so the water they contain gives us an invaluable insight into Earth’s early history and where its water came from.”

The study’s rocks furnish little deuterium, an isotope known as heavy hydrogen because of its atomic mass of two, in contrast to hydrogen’s atomic mass of one. They generate different hydrogen-to-deuterium ratios than the chemical compositions of cometary, meteorite or ocean water.

They have little helium.

The paucity of deuterium indicates water-rich dust drawing together from the solar disk to form Earth, not water molecules transported by asteroids, comets or meteorites to an already composed, cooled Blue Planet.

As a cosmochemist, Dr. Hallis judges it likely that “Even though a good deal of water would have been lost at the surface through evaporation in the heat of the formation process, enough survived to form the world’s water.”

Water cycling between interiors and surfaces keeps ocean waters from representing the Earth’s original deuterium/hydrogen signature. The isolation of Baffin’s volcanic basalt rocks and Iceland’s Holuhraun lava fields leads the six co-authors and co-researchers to consider deep-mantle deuterium/hydrogen ratio values more negative than minus 218 per mil.

Strongly negative values make direct inheritance from protosolar nebula likelier water sources than later drop-offs by water-rich asteroids, comets or meteorites 4.1 to 3.8 billion years ago.

Dr. Hallis notes that “It’s an exciting discovery, and one which we simply didn’t have the technology to make just a few years ago. We’re looking forward to further research in this area in the future.”

The likelihood of water as part of, not subsequent to, terrestrial birth processes offers research possibilities and theoretical implications for planets in the Solar System and the Milky Way. It prompts Horst Marschall, Woods Hole Oceanographic Institution geoscientist uninvolved in the investigation and publication, to state “That would make habitable worlds much more likely.”

aerial photograph of fissure eruptions in Iceland’s Holuhraun lava fields, Sept. 11, 2014; some of gas emitted during mantle plume-fed eruption is thought to be water vapor sourced from mantle plume. Rocks from Canada's Baffin Bay and Iceland's Holuhraun lava fields contain water that is low in deuterium, a hydrogen isotope known as "heavy hydrogen.": Fangorn9, CC BY SA 4.0, via Wikimedia Commons

Acknowledgment

My special thanks to talented artists and photographers/concerned organizations who make their fine images available on the internet.

Image credits:

Scanning electron microscope images of Baffin Island rock samples with olivine mineral grains (A) and trapped pockets of glass, known as melt inclusions (B), containing tiny amounts of water sourced from mantle plumeolivine-hosted melt inclusions: "Researchers shed new light on the origins of Earth's water.": The SETI Institute @SETIInstitute via Twitter Nov. 13, 2015, @ https://twitter.com/SETIInstitute/status/665186941336424448

aerial photograph of fissure eruptions in Iceland’s Holuhraun lava field, Sept. 11, 2014; some of gas emitted during mantle plume-fed eruption is thought to be water vapor sourced from mantle plumed: Fangorn9, CC BY SA 4.0, via Wikimedia Commons @ https://commons.wikimedia.org/wiki/File:Vulkanausbruch_Holuhraun.JPG

For further information:

GeoBeats News. 15 November 2015. "Study Estimates Age of Earth's Water." YouTube.
Available @ https://www.youtube.com/watch?v=bAjfHDLzTCw

Gray, Richard. 13 November 2015. "How Earth Became the Blue Planet: Lava from Deep within the Mantle Suggests Our World Formed with Water Already on It." Daily Mail > Science.
Available @ http://www.dailymail.co.uk/sciencetech/article-3316880/How-Earth-blue-planet-Lava-deep-mantle-suggests-world-formed-water-it.html

Hallis, Lydia J., et al. 13 November 2015. "Evidence for Primordial Water in Earth's Deep Mantle." Science, vol. 350, issue 6262 (Nov. 13, 2015): 795-797. DOI: 10.1125/science.aac4834
Available @ http://www.sciencemag.org/content/350/6262/795

The SETI Institute @SETIInstitute. 13 November 2015. "Researchers shed new light on the origins of Earth's water." Twitter.
Available @ https://twitter.com/SETIInstitute/status/665186941336424448

UH News. 16 November 2015. "New Light Shed on the Origins of Earth's Water." University of Hawai'i News.
Available @ http://www.hawaii.edu/news/2015/11/16/new-light-shed-on-the-origins-of-earths-water/

UofG News @UofGNews. 13 November 2015. "New research sheds light on the origins of Earth's water." Twitter.
Available @ https://twitter.com/UofGNews/status/665105967676301312