Featured Research

from universities, journals, and other organizations

Extraterrestrial Platinum Was 'Stirred' Into Earth

Date:
August 1, 2009
Source:
CSIRO Australia
Summary:
A research program aimed at using platinum as an exploration guide for nickel has for the first time been able to put a time scale on the planet's large-scale convection processes.

Outcrop of komatiite lava from the type locality in the Komati Valley, Barberton Mountainland, South Africa, showing the distinctive 'spinifex texture' formed by dendritic plates of olivine. The plates get smaller and more randomly oriented towards the top of the flow, at the top of the image.
Credit: Image courtesy of CSIRO Australia

A research program aimed at using platinum as an exploration guide for nickel has for the first time been able to put a time scale on the planet’s large-scale convection processes.

Report author CSIRO Minerals Down Under Flagship researcher Dr Stephen Barnes said the study group collected a large body of data on the platinum content of lava flows called komatiites, which host some of the world’s major nickel deposits.

“We found that the oldest komatiites have the lowest platinum content,” Dr Barnes said.

“The platinum content gradually increases from about 3.5 billion years to 2.9 billion years ago.

“This tells us that the deep source where the komatiite came from, down near the boundary between the Earth’s core and mantle, was gradually gaining platinum over time”.

The paper’s authors now think they know why.

“When the Earth’s core formed, it took all the available platinum with it, leaving the mantle and crust with none,” Dr Barnes said.

“Following that, a steady rain of meteorites created the so-called Late Veneer – a thin surface layer of meteorite debris rich in platinum.”

With time through large-scale convection processes, which now cause plate tectonics, this material was stirred down into the interior of the Earth.

We are seeing the signal of that stirring, which took about 1.5 billion years to occur.

This is the first time a time scale has been put on the stirring, which has important implications for the people who study the dynamics of mantle processes and the mechanisms that cause plate tectonics, earthquakes and volcanoes.

Combined with some other work by the researchers on sister elements to platinum, iridium and osmium, we also now have a new framework for understanding the variations in isotopic ratios of osmium with time.

Osmium isotopes are widely used as tracers of mantle processes, but there has been a mismatch between signals from osmium and from other important isotopic tracer systems which has eluded explanation until now.

Co-authors Dr Marco Fiorentini and Dr Wolfgang Maier from the University of Western Australia are delighted that this is a completely academic outcome which came out of an industry-funded project.


Story Source:

The above story is based on materials provided by CSIRO Australia. Note: Materials may be edited for content and length.


Journal Reference:

  1. Maier et al. Progressive mixing of meteoritic veneer into the early Earth's deep mantle. Nature, 2009; 460 (7255): 620 DOI: 10.1038/nature08205

Cite This Page:

CSIRO Australia. "Extraterrestrial Platinum Was 'Stirred' Into Earth." ScienceDaily. ScienceDaily, 1 August 2009. <www.sciencedaily.com/releases/2009/07/090731085813.htm>.
CSIRO Australia. (2009, August 1). Extraterrestrial Platinum Was 'Stirred' Into Earth. ScienceDaily. Retrieved September 18, 2014 from www.sciencedaily.com/releases/2009/07/090731085813.htm
CSIRO Australia. "Extraterrestrial Platinum Was 'Stirred' Into Earth." ScienceDaily. www.sciencedaily.com/releases/2009/07/090731085813.htm (accessed September 18, 2014).

Share This



More Earth & Climate News

Thursday, September 18, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Raw: Wildfires in CA Burn Forest Asunder

Raw: Wildfires in CA Burn Forest Asunder

AP (Sep. 18, 2014) An out-of-control Northern California wildfire has nearly 2,800 people from their homes as it continues to grow, authorities said Thursday. Authorities said a man has been arrested on suspicion of arson for starting the fire on Saturday. (Sept. 18) Video provided by AP
Powered by NewsLook.com
Raw: Elephant Undergoes Surgery in Tbilisi Zoo

Raw: Elephant Undergoes Surgery in Tbilisi Zoo

AP (Sep. 18, 2014) Grand the elephant has successfully undergone surgery to remove a portion of infected tusk at Tbilisi Zoo in Georgia. British veterinary surgeons used an electric drill to extract the infected piece. (Sept. 18) Video provided by AP
Powered by NewsLook.com
Raw: Scientists Examine Colossal Squid

Raw: Scientists Examine Colossal Squid

AP (Sep. 16, 2014) Squid experts in New Zealand thawed and examined an unusual catch on Tuesday: a colossal squid. It was captured in Antarctica's remote Ross Sea in December last year and has been frozen for eight months. (Sept. 16) Video provided by AP
Powered by NewsLook.com
Man Floats for 31 Hours in Gulf Waters

Man Floats for 31 Hours in Gulf Waters

AP (Sep. 16, 2014) A Texas man is lucky to be alive after he and three others floated for more than a day in the Gulf of Mexico when their boat sank during a fishing trip. (Sept. 16) Video provided by AP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins