Featured Research

from universities, journals, and other organizations

Volcanoes Key To Earth's Oxygen Atmosphere

Date:
September 3, 2007
Source:
Penn State
Summary:
A switch from predominantly undersea volcanoes to a mix of undersea and terrestrial ones shifted the Earth's atmosphere from devoid of oxygen to one with free oxygen, according to geologists. Before 2.5 billion years ago, the Earth's atmosphere lacked oxygen. However, biomarkers in rocks 200 million years older than that period, show oxygen-producing cyanobacteria released oxygen at the same levels as today. The oxygen produced then, had to be going somewhere.

Eruption of volcano on Reunion island, August 2003.
Credit: iStockphoto/Koch Valιrie

A switch from predominantly undersea volcanoes to a mix of undersea and terrestrial ones shifted the Earth's atmosphere from devoid of oxygen to one with free oxygen, according to geologists.

"The rise of oxygen allowed for the evolution of complex oxygen-breathing life forms," says Lee R. Kump, professor of geoscience, Penn State.

Before 2.5 billion years ago, the Earth's atmosphere lacked oxygen. However, biomarkers in rocks 200 million years older than that period, show oxygen-producing cyanobacteria released oxygen at the same levels as today. The oxygen produced then, had to be going somewhere.

"The absence of oxidized soil profiles and red beds indicates that oxidative weathering rates were negligible during the Archaean," the researchers report in the Aug. 30 issue of Nature.

The ancient Earth should have had an oxygen atmosphere but something was converting, reducing, the oxygen and removing it from the atmosphere. The researchers suggest that submarine volcanoes, producing a reducing mixture of gases and lavas, effectively scrubbed oxygen from the atmosphere, binding it into oxygen containing minerals.

"The Archaean more than 2.5 billion years ago seemed to be dominated by submarine volcanoes," says Kump. "Subaerial andesite volcanoes on thickened continental crust seem to be almost absent in the Archaean."

About 2.5 billion years ago at the Archaean/Proterozoic boundary, when stabilized continental land masses arose and terrestrial volcanoes appeared, markers show that oxygen began appearing in the atmosphere.

Kump and Mark E. Barley, professor of geology, University of Western Australia, looked at the geologic record from the Archaean and the Palaeoproterozoic in search of the remains of volcanoes. They found that the Archaean was nearly devoid of terrestrial volcanoes, but heavily populated by submarine volcanoes. The Palaeoproterozoic, however, had ample terrestrial volcanic activity along with continuing submarine vulcanism. Subaerial volcanoes arose after 2.5 billion years ago and did not strip oxygen from the air. Having a mix of volcanoes dominated by terrestrial volcanoes allowed oxygen to exist in the atmosphere.

Terrestrial volcanoes could become much more common in the Palaeoproterozoic because land masses stabilized and the current tectonic regime came into play.

The researchers looked at the ratio of submarine to subaerial volcanoes through time. Because submarine volcanoes erupt at lower temperatures than terrestrial volcanoes, they are more reducing. As long as the reducing ability of the submarine volcanoes was larger than the amounts of oxygen created, the atmosphere had no oxygen. When terrestrial volcanoes began to dominate, oxygen levels increased.

The National Science Foundation, NASA Astrobiology Institute and the Australian Research Council supported this work.


Story Source:

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


Cite This Page:

Penn State. "Volcanoes Key To Earth's Oxygen Atmosphere." ScienceDaily. ScienceDaily, 3 September 2007. <www.sciencedaily.com/releases/2007/08/070829143713.htm>.
Penn State. (2007, September 3). Volcanoes Key To Earth's Oxygen Atmosphere. ScienceDaily. Retrieved October 20, 2014 from www.sciencedaily.com/releases/2007/08/070829143713.htm
Penn State. "Volcanoes Key To Earth's Oxygen Atmosphere." ScienceDaily. www.sciencedaily.com/releases/2007/08/070829143713.htm (accessed October 20, 2014).

Share This



More Earth & Climate News

Monday, October 20, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Raw: Powerful Hurricane Gonzalo Heads to Bermuda

Raw: Powerful Hurricane Gonzalo Heads to Bermuda

AP (Oct. 17, 2014) — Hurricane Gonzalo pounded Bermuda with wind and heavy surf on Friday, bearing down on the tiny British territory as a powerful Category 3 storm that could raise coastal seas as much as 10 feet. (Oct. 17) Video provided by AP
Powered by NewsLook.com
So, Kangaroos Didn't Always Hop

So, Kangaroos Didn't Always Hop

Newsy (Oct. 16, 2014) — Researchers believe an extinct kangaroo species weighed 500 pounds or more and couldn't hop. Video provided by Newsy
Powered by NewsLook.com
Hurricane Gonzalo Is A Category 4 And Heading To Bermuda

Hurricane Gonzalo Is A Category 4 And Heading To Bermuda

Newsy (Oct. 16, 2014) — Powerful hurricane could hit Bermuda this weekend, and even if it misses it will likely do some damage. Video provided by Newsy
Powered by NewsLook.com
The Largest Volcano In Centuries Is Spewing Toxic Gas

The Largest Volcano In Centuries Is Spewing Toxic Gas

Newsy (Oct. 16, 2014) — One of the largest volcanic eruptions in centuries is occurring on Iceland. The volcano Bardarbunga is producing high levels of sulfur dioxide. 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