Green | July 27, 2008 | 7 comments

Rise, fall of ancient supercontinents likely liberated oxygen for us

source: http://www.usatoday.com/tech/science/columnist/vergano/2008-07-27-supercontinents-oxygen_N.h...

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TravG73
A study of ancient "super-continents" in the current Nature Geosciences suggests that the Earth and Sky have actually been changing each other for eons. A good thing, too, report the researchers, because the rise and fall of ancient supercontinents may have liberated the life-giving oxygen in the air we breathe.

Atmospheric oxygen concentrations in the Earth's atmosphere rose from negligible levels in the Archaean Era to about 21% in the present day. This increase is thought to have occurred in six steps, 2.65, 2.45, 1.8, 0.6, 0.3 and 0.04 billion years ago, with a possible seventh event identified at 1.2 billion years ago. Here we show that the timing of these steps correlates with the amalgamation of Earth's land masses into supercontinents. We suggest that the continent–continent collisions required to form supercontinents produced supermountains. In our scenario, these supermountains eroded quickly and released large amounts of nutrients such as iron and phosphorus into the oceans, leading to an explosion of algae and cyanobacteria, and thus a marked increase in photosynthesis, and the photosynthetic production of O2. Enhanced sedimentation during these periods promoted the burial of a high fraction of organic carbon and pyrite, thus preventing their reaction with free oxygen, and leading to sustained increases in atmospheric oxygen.
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7 comments // Rise, fall of ancient supercontinents likely liberated oxygen for us

  • arcticspirit
    • 0
      arcticspirit  
    • Image

    • I thought it was the algae in the water and oceans that sustained us with the most O2.

      I can see how breaking apart the land mass would allow that O2 to "cover more ground" so to speak.

      Cool news :) Thanks.

    • 3 years ago
  • BentFranklin
    • 0
      BentFranklin  

    • Interesting article. Just one nit to pick: Europe and North America are currently moving apart from each other so I wouldn't expect them to collide any time soon.

    • 3 years ago
  • M_Pavlov
  • jhydo
    • 0
      jhydo  

    • Now, that's a different way to spin it? Whatever way we want to slice it the inevitable fact is that whatever resource this rock conjures it is not finite. Human species cannot keep increasing with no consequence to the environment.

    • 3 years ago
  • Relevations
    • 0
      Relevations  

    • Not much is ever said about how this planet has grown....if you are reading this.....you have mostly completed a journey that you started as microscopic.....go look in the mirror.....you are an accumulator.....so is this planet.......it grows continuously....for a brief time in the history of Earth.....you are witness to the most glorious carnival in the Universe.....so how do you spend your time......in fear.....trying to kill each other......not being able to communicate with the rest of the world.....does that make sense to you.....well....it sure does not to me.......here's an equation for you......more people......less oxygen.......if you have ever witnessed someone who can not breath dying.....it is a bad way to spend your last hours at the carnival.......Golden Ruler.......Johnnie Hargrave..........

    • 3 years ago
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