Subscribe to our free daily newsletters
. 24/7 Space News .




Subscribe to our free daily newsletters



CARBON WORLDS
Large, rare diamonds offer window into inner workings of Earth's mantle
by Staff Writers
New York NY (SPX) Dec 21, 2016


This is a close-up view of a metallic inclusion. The inclusion is reflective/silver in appearance, surrounded by a black, graphite-bearing decompression crack. Image is 2.56 mm wide. Image courtesy Evan Smith and GIA.

Breakthrough research led by GIA Postdoctoral Research Fellow Evan Smith examines diamonds of exceptional size and quality to uncover clues about Earth's geology. The researchers studied the unique properties of diamonds with similar characteristics to famous stones such as the Cullinan, Constellation and Koh-i-Noor to advance our understanding of Earth's deep mantle, hidden beneath tectonic plates and largely inaccessible for scientific observation. The study is published in the most recent issue of Science magazine.

"Some of the world's largest and most valuable diamonds, like the Cullinan or Lesotho Promise, exhibit a distinct set of physical characteristics that have led many to regard them as separate from other, more common diamonds. However, exactly how these diamonds form and what they tell us about the Earth has remained a mystery until now," explains Dr. Wuyi Wang, GIA's director of research and development, and an author of the study.

Large gem diamonds like the Cullinan have a set of physical characteristics that distinguish them from other kinds of diamonds. The new research shows these Cullinan-like gems sometimes have small metallic inclusions - or internal characteristics - trapped within them. The metallic inclusions coexist with traces of fluid methane and hydrogen.

In addition to the metallic inclusions, some of these exceptional diamonds contain mineral inclusions that show the diamonds formed at extreme depths, likely within 360-750 km (approximately 224-466 miles) in the convecting mantle. This is much deeper than most other gem diamonds, which form in the lower part of continental tectonic plates at depths of 150-200 km (approximately 93-124 miles).

"This new understanding of these large, type IIa diamonds resolves one of the major enigmas in the study of diamond formation - how the world's largest and most valuable diamonds formed," says Smith. "The composition of the inclusions, however, provides the story."

The metallic inclusions are a solidified mixture of iron, nickel, carbon and sulfur, also containing traces of fluid methane and hydrogen in the thin tiny space between the metallic phases and the encasing diamond.

Pure carbon crystallized in this mix of molten metallic liquid in Earth's deep mantle to form diamonds. Small droplets of this metallic liquid were occasionally trapped within the diamonds as they grew. During cutting and polishing, parts of the diamond that contain inclusions are often cut off or polished away to craft exquisite polished gems with minimal flaws.

These cut diamond pieces are not normally available for research, but because of GIA's unique position as an independent, nonprofit research organization, Dr. Smith and his coauthors were able to study the inclusions for this investigation.

"Previous experiments and theory predicted for many years that parts of the deep mantle below about 250 km depth contain small amounts of metallic iron and have limited available oxygen. Now, the metallic inclusions and their surrounding methane and hydrogen jackets in these diamonds provide consistent, systematic physical evidence to support this prediction," explains Smith.

Though the extent of metal distribution is uncertain, this key observation has broad implications for understanding the behavior of the deep Earth, including the recycling of surface rocks into the convecting mantle, and the deep storage and cycling of carbon and hydrogen in the mantle through geologic time.

Research paper


Comment on this article using your Disqus, Facebook, Google or Twitter login.


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
Gemological Institute of America
Carbon Worlds - where graphite, diamond, amorphous, fullerenes meet






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

Previous Report
CARBON WORLDS
Big diamonds have liquid metal roots, deep in the Earth
Washington DC (SPX) Dec 21, 2016
After closely inspecting massive diamonds, scientists suggest they not only have unusual sizes but also unusual origins. Slivers of embedded iron in these gems, surrounded by special gases, point to a liquid metal origin and also confirm metal-saturated conditions deep in the Earth, the researchers say. To date, geologists have puzzled over the origin of large diamonds like the fam ... read more


CARBON WORLDS
'Passengers' and the real-life science of deep space travel

NASA Readies for Major Orion Milestones in 2017

India achieves advances multiple space systems in 2016

Spacewalk for Thomas Pesquet at ISS

CARBON WORLDS
New round of wind tunnel tests underway for more bigger SLS version

United Launch Alliance launches EchoStar XIX satellite

Preparing to Plug Into NASA SLS Fuel Tank

Ultra-Cold Storage - Liquid Hydrogen may be Fuel of the Future

CARBON WORLDS
Small Troughs Growing on Mars May Become 'Spiders'

All eyes on Trump over Mars

Opportunity performs several drives to ancient gully

Full go-ahead for building ExoMars 2020

CARBON WORLDS
Chinese missile giant seeks 20% of a satellite market

China-made satellites in high demand

Space exploration plans unveiled

China launches 4th data relay satellite

CARBON WORLDS
Airbus DS and Energia eye new medium-class satellite platform

OneWeb announces key funding form SoftBank Group and other investors

Space as a Driver for Socio-Economic Sustainable Development

Intel acquires ESA incubator company

CARBON WORLDS
Ultra-small nanocavity advances technology for secure quantum-based data encryption

Meet a 'Spacecraft Dressmaker'

Ultra-high-speed optical fiber sensor enables detection of structural damage in real time

NASA Satellite Servicing Office Becomes a Projects Division

CARBON WORLDS
Astronomers discover dark past of planet-eating 'Death Star'

Microlensing Study Suggests Most Common Outer Planets Likely Neptune-mass

Searching a sea of 'noise' to find exoplanets - using only data as a guide

The blob can learn and teach

CARBON WORLDS
Exploring Pluto and the Wild Back Yonder

Juno Captures Jupiter 'Pearl'

Juno Mission Prepares for December 11 Jupiter Flyby

Research Offers Clues About the Timing of Jupiter's Formation




Memory Foam Mattress Review
Newsletters :: SpaceDaily :: SpaceWar :: TerraDaily :: Energy Daily
XML Feeds :: Space News :: Earth News :: War News :: Solar Energy News






The content herein, unless otherwise known to be public domain, are Copyright 1995-2017 - 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. All articles labeled "by Staff Writers" include reports supplied to Space Media Network by industry news wires, PR agencies, corporate press officers and the like. Such articles are individually curated and edited by Space Media Network staff on the basis of the report's information value to our industry and professional readership. 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