Featured Research

from universities, journals, and other organizations

Zircons and their message from the Earth’s mantle

Date:
January 8, 2010
Source:
Universitaet Tuebingen
Summary:
Zircon is a mineral that exists in nature from colorless to reddish-brown, yellow, green or blue. Zircon may also be transparent making its visual appearance similar to a diamond. Zircon is a common accessory mineral in many rocks of the continental crust. Their chemical and physical durability allow this mineral to survive even under the pressure and temperature conditions of the Earth’s upper mantle. These characteristics challenged a group of scientists to take a closer look on zircons from basaltic fields in north-eastern Bavaria. Their results show that these zircons were formed in the Earth mantle and were stored in this environment many million of years before they were delivered to the surface by basalt lava flows with which they are associated.

Zircons from basaltic fields in north-eastern Bavaria.
Credit: Photo: Stefan Meier

Zircon is a mineral that exists in nature from colourless to reddish-brown, yellow, green or blue. Zircon may also be transparent making its visual appearance similar to diamond. Zircon is a common accessory mineral in many rocks of the continental crust. Their chemical and physical durability allow this mineral to survive even under the pressure and temperature conditions of the Earth's upper mantle.

Related Articles


These characteristics challenged a group of scientists from Tόbingen (Germany), Los Angeles (USA), Perth (Australia) and Hefei (China) to take a closer look on zircons from basaltic fields in north-eastern Bavaria. Their results show that these zircons were formed in the Earth mantle and were stored in this environment many million of years before they were delivered to the surface by basalt lava flows with which they are associated. Their study appears online in Nature Geoscience.

The scientists have chosen exceptional large crystals (1 to 3 mm in diameter) of gem quality which were recently discovered in placer deposits within the western segment of the central European Eger rift system. A number of experiments were carried out the crystals including in situ trace element analyses, oxygen isotope composition and isotope analyses of the decay products of the radioactive elements Lutetium, Samarium und Uranium.

Uranium-thorium-helium-dating revealed that the zircons were transported to the surface environment by basalt eruptions 29 to 24 million years ago. Their trace element composition points to formation depths of 60-80 km under relatively low temperature conditions (850-950°C). The zircons reveal uranium-lead ages from 80 to 50 million years considerably older than their eruption age. There is no evidence that the zircons were stored in the crust prior to eruption. Obviously the zircon fragments resisted dissolution and diffusive element loss to various extents and survived partly unscathed in the upper mantle.

This is a remarkable finding given that the temperature increased within the shallow mantle below the Eger rift in the geological past as known from other studies. Zircons like these, apart from their aesthetic beauty, carry a wealth of information and offer an interesting glimpse in the mantle.


Story Source:

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


Journal Reference:

  1. Siebel et al. Prolonged mantle residence of zircon xenocrysts from the western Eger rift. Nature Geoscience, 2009; DOI: 10.1038/ngeo695

Cite This Page:

Universitaet Tuebingen. "Zircons and their message from the Earth’s mantle." ScienceDaily. ScienceDaily, 8 January 2010. <www.sciencedaily.com/releases/2009/11/091127133919.htm>.
Universitaet Tuebingen. (2010, January 8). Zircons and their message from the Earth’s mantle. ScienceDaily. Retrieved December 21, 2014 from www.sciencedaily.com/releases/2009/11/091127133919.htm
Universitaet Tuebingen. "Zircons and their message from the Earth’s mantle." ScienceDaily. www.sciencedaily.com/releases/2009/11/091127133919.htm (accessed December 21, 2014).

Share This


More From ScienceDaily



More Earth & Climate News

Sunday, December 21, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Raw: Lava on Track to Hit Hawaii Market

Raw: Lava on Track to Hit Hawaii Market

AP (Dec. 19, 2014) — Lava from an active volcano on Hawaii's Big Island slowed slightly but stayed on track to hit a shopping center in the small town of Pahoa. (Dec. 19) Video provided by AP
Powered by NewsLook.com
Birds Might Be Better Meteorologists Than Us

Birds Might Be Better Meteorologists Than Us

Newsy (Dec. 19, 2014) — A new study suggests a certain type of bird was able to sense a tornado outbreak that moved through the U.S. a day before it hit. Video provided by Newsy
Powered by NewsLook.com
Navy Unveils Robot Fish

Navy Unveils Robot Fish

Reuters - Light News Video Online (Dec. 18, 2014) — The U.S. Navy unveils an underwater device that mimics the movement of a fish. Tara Cleary reports. Video provided by Reuters
Powered by NewsLook.com
Arctic Warming Twice As Fast As Rest Of Planet

Arctic Warming Twice As Fast As Rest Of Planet

Newsy (Dec. 18, 2014) — The Arctic is warming twice as fast as the rest of the planet, thanks in part to something called feedback. Video provided by Newsy
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:

Strange & Offbeat Stories

 

Plants & Animals

Earth & Climate

Fossils & Ruins

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