Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Isotopic Memory of Atmospheric Persistence

16.01.2015

Chemical analysis of ancient rocks reveals earliest record yet of Earth's atmosphere

Chemical analysis of some of the world’s oldest rocks, by an international team led by McGill University researchers, has provided the earliest record yet of Earth's atmosphere. The results show that the air 4 billion years ago was very similar to that more than a billion years later, when the atmosphere -- though it likely would have been lethal to oxygen-dependent humans -- supported a thriving microbial biosphere that ultimately gave rise to the diversity of life on Earth today.


Boswell Wing, McGill University

Rocks of the Ujaraaluk unit of the Nuvvuagittuq Greenstone Belt

The findings, published last week in the Proceedings of the National Academy of Sciences, could help scientists better understand how life originated and evolved on the planet. Until now, researchers have had to rely on widely varying computer models of the earliest atmosphere's characteristics.

The new study builds on previous work by former McGill PhD student Jonathan O’Neil (now an assistant professor at Ottawa University) and McGill emeritus professor Don Francis, who reported in 2008 that rocks along the Hudson Bay coast in northern Quebec, in an area known as the Nuvvuagittuq Greenstone Belt, were deposited as sediments as many as 4.3 billion years ago -- a couple of hundred million years after the Earth formed.

In the new study, a team led by researchers from McGill’s Earth and Planetary Sciences Department, used mass spectrometry to measure the amounts of different isotopes of sulfur in rocks from the Nuvvuagittuq belt. The results enabled the scientists to determine that the sulfur in these rocks, which are at least 3.8 billion years old and possibly 500 million years older, had been cycled through the Earth's early atmosphere, showing the air at the time was extremely oxygen-poor compared to today, and may have had more methane and carbon dioxide.

"We found that the isotopic fingerprint of this atmospheric cycling looks just like similar fingerprints from rocks that are a billion to 2 billion years younger," said Emilie Thomassot, a former postdoctoral researcher at McGill and lead author of the paper. Emilie Thomassot is now with the Centre de Recherches Pétrographiques et Géochimiques (CRPG) in Nancy France.

“Those younger rocks contain clear signs of microbial life and there are a couple of possible interpretations of our results," says Boswell Wing, an associate professor at McGill and co-author of the new study. "One interpretation is that biology controlled the composition of the atmosphere on early Earth, with similar microbial biospheres producing the same atmospheric gases from Earth’s infancy to adolescence. We can’t rule out, however, the possibility that the biosphere was decoupled from the atmosphere. In this case geology could have been the major player in setting the composition of ancient air, with massive volcanic eruptions producing gases that recurrently swamped out weak biological gas production."

The research team is now extending its work to try to tell whether the evidence supports the “biological” or the “geological” hypothesis -- or some combination of both. In either case Emilie Thomassot says, the current study "demonstrates that the Nuvvuagittuq sediments record a memory of Earth’s surface environment at the very dawn of our planet. And surprisingly, this memory seems compatible with a welcoming terrestrial surface for life". The team is now extending their investigation to early Archean sediments from other localities in Canada, such as the Labrador coast (see www.saglek-expedition.org).

The research was supported by the Natural Sciences and Engineering Research Council of Canada and the Canadian Space Agency, and by France’s Lorraine region and the Centre National de la Recherche Scientifique.

"Atmospheric record in the Hadean Eon from multiple sulfur isotope measurements in Nuvvuagittuq Greenstone Belt (Nunavik, Quebec)" E. Thomassot, J. O’Neil, D. Francis, P. Cartigny, B. A. Wing. Proceedings of the National Academy of Sciences, published online Jan. 5, 2015.
www.pnas.org/cgi/doi/10.1073/pnas.1419681112

Contact Information
Cynthia Lee
cynthia.lee@mcgill.ca

Cynthia Lee | newswise
Further information:
http://www.mcgill.ca

Further reports about: Atmosphere Earth Isotopic McGill Persistence Sciences composition gases microbial sediments sulfur

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Fizzy soda water could be key to clean manufacture of flat wonder material: Graphene

Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.

As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...

Im Focus: Exotic quantum states made from light: Physicists create optical “wells” for a super-photon

Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.

Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...

Im Focus: Circular RNA linked to brain function

For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.

While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...

Im Focus: RAVAN CubeSat measures Earth's outgoing energy

An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.

The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...

Im Focus: Scientists shine new light on the “other high temperature superconductor”

A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.

Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Call for Papers – ICNFT 2018, 5th International Conference on New Forming Technology

16.08.2017 | Event News

Sustainability is the business model of tomorrow

04.08.2017 | Event News

Clash of Realities 2017: Registration now open. International Conference at TH Köln

26.07.2017 | Event News

 
Latest News

A Map of the Cell’s Power Station

18.08.2017 | Life Sciences

Engineering team images tiny quasicrystals as they form

18.08.2017 | Physics and Astronomy

Researchers printed graphene-like materials with inkjet

18.08.2017 | Materials Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>