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Earth Science

Earth May Have Been a 'Water World' 3 Billion Years Ago, Scientists Find (theguardian.com) 84

Posted by BeauHD from the water-as-far-as-the-eye-can-see dept.
An anonymous reader quotes a report from The Guardian: Scientists have found evidence that Earth was covered by a global ocean that turned the planet into a "water world" more than 3 billion years ago. Telltale chemical signatures were spotted in an ancient chunk of ocean crust which point to a planet once devoid of continents, the largest landmasses on Earth. If the findings are confirmed by future work, they will help researchers to refine their theories on where and how the first single-celled life emerged on Earth, and what other worlds may be habitable.

"An early Earth without emergent continents may have resembled a 'water world', providing an important environmental constraint on the origin and evolution of life on Earth, as well as its possible existence elsewhere," the scientists write in Nature Geoscience. Their work centered on a geological site called the Panorama district in north-western Australia's outback, where a 3.2 billion-year-old slab of ocean floor has been turned on its side. Locked inside the ancient crust are chemical clues about the seawater that covered Earth at the time. The scientists focused on different types of oxygen that seawater had carried into the crust. In particular, they analyzed the relative amounts of two isotopes, oxygen-16 and the ever-so-slightly-heavier oxygen-18, in more than 100 samples of the stone. They found that seawater contained more oxygen-18 when the crust was formed 3.2 billion years ago. The most likely explanation, they believe, is that Earth had no continents at the time, because when these form, the clays they contain absorb the ocean's heavy oxygen isotopes. The Earth wasn't entirely landless, however. "The scientists suspect that small 'microcontinents' may have poked out of the ocean here and there," the report adds. "But they do not think the planet hosted vast soil-rich continents like those that dominate Earth today."
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Earth May Have Been a 'Water World' 3 Billion Years Ago, Scientists Find More

Earth May Have Been a 'Water World' 3 Billion Years Ago, Scientists Find

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  • Can I summarize this as... (Score:4, Interesting)

    by aeropage ( 6536406 ) on Monday March 02, 2020 @10:34PM (#59790332)

    ..."divided the waters from the waters"?

    Just checking.

    • Re: (Score:2, Insightful)

      by serviscope_minor ( 664417 )

      Re:Can I summarize this as...

      Sure, why not.

      I will give you today's internet prize for the most resoundingly boring attempt at a troll.

    • Sure. If you don't mind me asking where you get the idea from that anything was divided.

    • Re: (Score:2)

      by gtall ( 79522 )

      Ok, who helped Pence get an account here?

    • No, you can't.

      • Considering I just factually did, your position appears rather anti-empirical.

        • That may depend on what you meant by "can". If you meant that it's something would be physically able to write, of course, you can write whatever you want. If you meant by it whether it would have even an inkling of a sense to do that, no, it didn't. It makes no sense at all.

          • It directly describes the scientific historical facts, if not in detail. How you twist your rationalizing mind like this, I'll never know.

            • Re: (Score:2)

              by cusco ( 717999 )

              So you also hold that the Earth, water with waves on it and the wind all existed before light did (or maybe before the Sun ignited, if we want to be generous)? That's what your holy book claims.

              http://www.vatican.va/archive/... [vatican.va]

            • No, it doesn't describe "scientific historical facts". First of all, history starts with writing. Second, geological events were totally different than this.
  • The earth could have been everything we can think of

  • Well known to geologists (Score:4, Informative)

    by jfdavis668 ( 1414919 ) on Monday March 02, 2020 @10:43PM (#59790364)
    Yes, they found another point of evidence, but it is well recognized that when water cooled and formed liquid, it quickly covered nearly the entire surface. The process that produces continental crust had just begun, and there were only small points of land sticking out of the ocean.

    • Absolutely right, not news. The process creating continental crust is called differentiation. The system has to be stable enough for the heavy stuff to sink and the light stuff to float to the top (of the molten materials), before that only small chunks of lighter material stuck up above a pretty smooth sphere.

      • Not only were there water phases (probably more than one) not news to geologists, there were other phases, too.

        The paper is just yet another confirmation of water half the Hadean Eon. The first half was very hot and traumatic likely due to the impact that caused us to now have the moon, which probably broke up the planet and had it reform. The second half included water settling out, flooding the world. The paper just adds more evidence of this.

        The more interesting one to me was how the entire earth was fro

    • Irrelevant (Score:4, Interesting)

      by Viol8 ( 599362 ) on Tuesday March 03, 2020 @05:39AM (#59790922) Homepage

      When a planet forms there will be so many asteroid impacts that it will not be anything like a smooth billiard ball - look at mercury, venus or the moon. Therefore contentinal drift and the processes associated with it are not required to produce elevated areas of a planets surface so the chances of the earth being covered by an incredibly thin (relative to the planets diameter) layer of water with almost no land is probably pretty slim IMO and their theory that because clays absord O18 and there was plenty of O18 in earths early oceans is a massive "so what?" There would be been little to no clays when the earth first formed.

      • Re: (Score:2)

        by cusco ( 717999 )

        Our meteorology instructor said, "Take a basketball, and dunk it in a bucket of water. If the Earth were the size of the ball the breathable atmosphere would be thinner than the film of water on the surface when you first take it out. The bumps are taller than Everest, the grooves are deeper than the Challenger Deep."

    • Yes, they found another point of evidence, but it is well recognized that when water cooled and formed liquid, it quickly covered nearly the entire surface. The process that produces continental crust had just begun, and there were only small points of land sticking out of the ocean.

      Good to see a sensible post in here.

      Surely. Without that process of drift/cooling, the water would end up being a shallow sort of ocean. My guess is that any exposed land would just be random parts of the accretion process. I didn't even realize this was a thing for scientists to "find", only to confirm a very likely process.

  • Who knew Waterworld was a documentary?

  • I always knew reality was based on a terrible movie.

  • If I were alive then, I'd be a fish.

  • I was expecting to find a name for this single body of water, in the same way that the 'single continent' was named Pangaea.

    (Researchers - please don't ask the Internet for suggestions, it'll end up being 'Ocean McSeaface' )

  • About two thirds of the surface is water, after all...
  • The dinosaurs in North Dakota were killed by a tsunami...water...in the middle of North America. The earth was once covered with water. Isn't there a few history books that say the same thing just in a different time frame? Where are the dinosaurs in those history books you ask? We called them dragons, and they are in there too.
    • This is talking about something very different than dinosaurs drowning in the North American inland sea during the Cretaceous.
  • Multi million year ice age, latest interglacial period, waterworld. Caused or sped up?
  • Is the earth normalizing, melting the ice to become a water world again. You better develop gills pronto if you expect to survive.

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