Featured Research

from universities, journals, and other organizations

Ancient Earth's geochemistry: Some tectonic processes driving volcanic activity occurred 3.8 billion years ago

Date:
January 18, 2013
Source:
Carnegie Institution
Summary:
Researchers still have much to learn about the volcanism that shaped our planet's early history. New evidence demonstrates that some of the tectonic processes driving volcanic activity, such as those taking place today, were occurring as early as 3.8 billion years ago.

Image of southwest Greenland.
Credit: Jacques Descloitres, MODIS Land Rapid Response Team, courtesy of NASA Visible Earth

Researchers still have much to learn about the volcanism that shaped our planet's early history. New evidence from a team led by Carnegie's Frances Jenner demonstrates that some of the tectonic processes driving volcanic activity, such as those taking place today, were occurring as early as 3.8 billion years ago. Their work is published in Geology.

Related Articles


Upwelling and melting of Earth's mantle at mid-ocean ridges, as well as the eruption of new magmas on the seafloor, drive the continual production of the oceanic crust. As the oceanic crust moves away from the mid-ocean ridges and cools it becomes denser than the underlying mantle. Over time the majority of this oceanic crust sinks back into the mantle, which can trigger further volcanic eruptions. This process is known as subduction and it takes place at plate boundaries.

Volcanic eruptions that are triggered by subduction of oceanic crust are chemically distinct from those erupting at mid-ocean ridges and oceanic island chains, such as Hawaii. The differences between the chemistry of magmas produced at each of these tectonic settings provide 'geochemical fingerprints' that can be used to try to identify the types of tectonic activity taking place early in Earth's history.

Previous geochemical studies have used similarities between modern subduction zone magmas and those erupted about 3.8 billion years ago, during the Eoarchean era, to argue that subduction-style tectonic activity was taking place early in Earth's history. But no one was able to locate any suites of volcanic rocks with compositions comparable to modern mid-ocean ridge or oceanic island magmas that were older than 3 billion years and were also free from contamination by continental crust.

Because of this missing piece of the puzzle, it has been ambiguous whether the subduction-like compositions of volcanic rocks erupted 3.8 billion years ago really were generated at subduction zones, or whether this magmatism should be attributed to other processes taking place early in Earth's history. Consequently, evidence for subduction-related tectonics earlier than 3 billion years ago has been highly debated in scientific literature.

Jenner and her team collected 3.8 billion-year-old volcanic rocks from Innersuartuut, an island in southwest Greenland, and found the samples have compositions comparable to modern oceanic islands, such as Hawaii.

"The Innersuartuut samples may represent the world's oldest recognized suite of oceanic island basalts, free from contamination by continental crust," Jenner said. "This evidence strengthens previous arguments that subduction of oceanic crust into the mantle has been taking place since at least 3.8 billion years ago."


Story Source:

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


Journal Reference:

  1. F. E. Jenner, V. C. Bennett, G. Yaxley, C. R. L. Friend, O. Nebel. Eoarchean within-plate basalts from southwest Greenland. Geology, 2013; DOI: 10.1130/G33787.1

Cite This Page:

Carnegie Institution. "Ancient Earth's geochemistry: Some tectonic processes driving volcanic activity occurred 3.8 billion years ago." ScienceDaily. ScienceDaily, 18 January 2013. <www.sciencedaily.com/releases/2013/01/130118130104.htm>.
Carnegie Institution. (2013, January 18). Ancient Earth's geochemistry: Some tectonic processes driving volcanic activity occurred 3.8 billion years ago. ScienceDaily. Retrieved March 29, 2015 from www.sciencedaily.com/releases/2013/01/130118130104.htm
Carnegie Institution. "Ancient Earth's geochemistry: Some tectonic processes driving volcanic activity occurred 3.8 billion years ago." ScienceDaily. www.sciencedaily.com/releases/2013/01/130118130104.htm (accessed March 29, 2015).

Share This


More From ScienceDaily



More Earth & Climate News

Sunday, March 29, 2015

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Antarctic Ice Is Melting Faster Than Ever

Antarctic Ice Is Melting Faster Than Ever

Newsy (Mar. 27, 2015) A new study of nearly two decades of satellite data shows Antarctic ice shelves are losing more mass faster every year. Video provided by Newsy
Powered by NewsLook.com
Raw: Homes Near Landslide in Washington

Raw: Homes Near Landslide in Washington

AP (Mar. 27, 2015) Aerial footage from KOMO shows several homes near a landslide in Washington. KOMO reports that at least one of the homes has been damaged. (March 27) Video provided by AP
Powered by NewsLook.com
Clean-Up Follows Deadly Weather in Okla.

Clean-Up Follows Deadly Weather in Okla.

AP (Mar. 26, 2015) Gov. Mary Fallin has declared a state of emergency for 25 Oklahoma counties after powerful storms rumbled across the state causing one death, numerous injuries and widespread damage. (March 26) Video provided by AP
Powered by NewsLook.com
At Least Four Dead After Floods in Northern Chile

At Least Four Dead After Floods in Northern Chile

Reuters - News Video Online (Mar. 26, 2015) At least four people have been killed by severe flooding in northern Chile after rains battered the Andes mountains and swept into communities below. Rob Muir reports. Video provided by Reuters
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