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 February 1, 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 February 1, 2015).

Share This


More From ScienceDaily



More Earth & Climate News

Sunday, February 1, 2015

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Hikers Rescued After Fall from Oregon Mountain

Hikers Rescued After Fall from Oregon Mountain

AP (Feb. 1, 2015) Two climbers who were hurt in a fall on Mount Hood are now being treated for their injuries. Rescue officials say they were airlifted off the mountain Saturday afternoon by an Oregon National Guard helicopter. (Feb. 2) Video provided by AP
Powered by NewsLook.com
NASA's SMAP Satellite Will Measure Wet Dirt From Space

NASA's SMAP Satellite Will Measure Wet Dirt From Space

Newsy (Feb. 1, 2015) NASA&apos;s Soil Moisture Active Passive satellite mission will collect data to help forecast crop productivity, floods, droughts and wildfires. Video provided by Newsy
Powered by NewsLook.com
Raw: Rare Clouds Fill Grand Canyon

Raw: Rare Clouds Fill Grand Canyon

AP (Jan. 29, 2015) For the second time in two months, a rare weather phenomenon filled the Grand Canyon with thick clouds just below the rim on Wednesday. (Jan. 29) Video provided by AP
Powered by NewsLook.com
Senate Passes Bill for Keystone XL Pipeline

Senate Passes Bill for Keystone XL Pipeline

AP (Jan. 29, 2015) The Republican-controlled Senate has passed a bipartisan bill approving construction of the Keystone XL oil pipeline. (Jan. 29) 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:

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