Featured Research

from universities, journals, and other organizations

Deep Mantle Volcanic Plumes Cause Of Atmospheric Oxygenation

Date:
November 20, 2000
Source:
Penn State
Summary:
If the initial rise in the Earth's atmospheric oxygen occurred between 2400 and 1800 million years ago, as most researchers agree, but oxygen producing bacteria existed more than 300 million years before that, Penn State geologists wonder what caused the delay?

Reno, Nev. - If the initial rise in the Earth's atmospheric oxygen occurred between 2400 and 1800 million years ago, as most researchers agree, but oxygen producing bacteria existed more than 300 million years before that, Penn State geologists wonder what caused the delay?

"Oddly enough, the rise of oxygen seems to be linked to what may have been Earth's first glaciation," says Dr. Lee R. Kump, professor of geosciences. "After the glaciation that occurred 2.4 billion years ago, the amount of oxygen in the Earth's atmospheric may have been about the same as it is today. Prior to that glaciation, the amount of oxygen was essentially zero, far below the amount necessary to support oxygen breathing life."

Kump and James F. Kasting, professor of geosciences and meteorology, together with their Australian Colleague Mark Barley, have developed a conceptual model that suggests vulcanism caused a rapid change in oxygen content and the glaciation, but this was a different type of vulcanism than had occurred up until then.

"Previous to 2.4 billion years ago, volcanoes spewed hydrogen, carbon monoxide and methane into the atmosphere because their magma source from the near upper mantle, was very reduced," Kump told attendees today (Nov. 15) at the annual meeting of the Geological Society of America in Reno, Nev.

Cyanobacteria produce oxygen from photosynthesis, but none of that oxygen remained in the atmosphere because the hydrogen, carbon monoxide and methane rapidly reduced it. These reducing gases produced a strong greenhouse effect keeping the Earth warm.

The action of water, which contains oxygen, on the iron in basalts emerging from mid-ocean ridges, set up the potential for a more oxygenated atmosphere. The iron in basalt rusted in contact with the water. The hydrogen produced escaped to the atmosphere but the rust - iron oxide -- deposited on the ocean floors. This oxygen rich layer eventually was subducted and accumulated at the core-mantle boundary, far from the area generating volcanic magmas.

"The likelihood that these deep mantles would rise as plumes of oxygenated magmas increased as more and more iron oxide rich magma was buried," says Kump. "What we do not know is why these deep plume volcanos appeared on three or four continents at the same time."

The rising plumes began to spew carbon dioxide and water, rather than methane and hydrogen, and this allowed the oxygen levels to rise.

"The weaker greenhouse caused by lower methane and carbon monoxide levels allowed glaciation to occur," says Kump.

The researchers suspect that glaciation came on rapidly and existed for only a short time. Once carbon dioxide built up in the atmosphere, its greenhouse warming potential would melt the glaciers.

"Geological observation shows that the same sequence of events occurs around the world at this time," says Kump. "There is evidence of reduced iron deposits, then glacial deposits and then oxidized sandstones indicating an oxygen rich atmosphere in Africa, Canada and Australia."

Kump, Kasting and Barley believe that their conceptual model of rapid oxygenation of the atmosphere by deep magma plume volcanos is self consistent and ties together a series of occurrences on different continents.


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. "Deep Mantle Volcanic Plumes Cause Of Atmospheric Oxygenation." ScienceDaily. ScienceDaily, 20 November 2000. <www.sciencedaily.com/releases/2000/11/001120073504.htm>.
Penn State. (2000, November 20). Deep Mantle Volcanic Plumes Cause Of Atmospheric Oxygenation. ScienceDaily. Retrieved July 28, 2014 from www.sciencedaily.com/releases/2000/11/001120073504.htm
Penn State. "Deep Mantle Volcanic Plumes Cause Of Atmospheric Oxygenation." ScienceDaily. www.sciencedaily.com/releases/2000/11/001120073504.htm (accessed July 28, 2014).

Share This




More Earth & Climate News

Monday, July 28, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

The Carbon Trap: US Exports Global Warming

The Carbon Trap: US Exports Global Warming

AP (July 28, 2014) AP Investigation: As the Obama administration weans the country off dirty fuels, energy companies are ramping-up overseas coal exports at a heavy price. (July 28) Video provided by AP
Powered by NewsLook.com
Raw: Sea Turtle Hatchlings Emerge from Nest

Raw: Sea Turtle Hatchlings Emerge from Nest

AP (July 27, 2014) A live-streaming webcam catches loggerhead sea turtle hatchlings emerging from a nest in the Florida Keys. (July 27) Video provided by AP
Powered by NewsLook.com
Trees Could Save More Than 850 Lives Each Year

Trees Could Save More Than 850 Lives Each Year

Newsy (July 27, 2014) A national study conducted by the USDA Forest Service found that trees collectively save more than 850 lives on an annual basis. Video provided by Newsy
Powered by NewsLook.com
Phoenix Thunderstorm Creates Giant Wall of Dust

Phoenix Thunderstorm Creates Giant Wall of Dust

Reuters - US Online Video (July 26, 2014) A giant wall of dust slowly moves north over the Phoenix area after a summer monsoon thunderstorm. Mana Rabiee 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:
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