Earth’s outer shell ballooned during massive growth spurt 3 billion years ago

Posted: January 23, 2021 by oldbrew in Geology, research


So the Earth is, or was, a kind of giant balloon. We know seafloor spreading is still ongoing, and can affect global sea levels on historical timescales.
– – –
Ancient fragments of Earth’s crust acted as ‘seeds’ for new crust to grow from, says LiveScience.

Around 3 billion years ago, Earth’s crust ballooned during a massive growth spurt, geoscientists have found.

At that time, just 1.5 billion years after Earth formed, the mantle — the layer of silicate rock between the crust and the outer core that was more active in the past — heated up, causing magma from that layer to ooze into fragments of older crust above it.

Those fragments acted as “seeds” for the growth of modern-day continents.

The researchers found evidence for this growth spurt hiding in ancient zircon crystals in stream sediments in Greenland. These extremely durable crystals — made up of zirconium silicate — formed during the growth spurt around 3 billion years ago.

“There have probably been multiple crust-forming events in the Earth’s history,” lead researcher Chris Kirkland, a professor of geoscience at Curtin University in Australia, told Live Science. “But this global injection event 3 billion years ago is definitely one of the biggest.”

Continental seeds

Before this massive growth period, Earth’s ancient crust was much thinner and weaker than it is today. Eventually, it broke apart into crustal fragments that served as floating “life rafts” from which new crust could grow.

“We think of crust as this buoyant material that sits on top of the mantle,” Kirkland said. “This means it constantly gets an injection of new material coming from below. The longer it sits on top, the more new material is injected into it and the larger it becomes.”

Mantle temperatures peaked at the time, due to the radioactive decay of elements like uranium and potassium in Earth’s core, as well as from residual heat left the planet’s formation.

Since that globe-wide peak in temperatures spurred the process, the crust continued to balloon on a massive scale for a period of roughly 200 million years, according to the researchers.

At the end of this period, the first continents began to take shape, eventually allowing for the development of complex life on land around 400 million years ago.

Continued here.

Study: Widespread reworking of Hadean-to-Eoarchean continents during Earth’s thermal peak — Nature Communications

Comments
  1. JB says:

    “We think of crust as this buoyant material that sits on top of the mantle,” Kirkland said. “This means it constantly gets an injection of new material coming from below. The longer it sits on top, the more new material is injected into it and the larger it becomes.”

    So the core of the earth is progressively more hollow? Wal Thornhill seems to think something on that order is going on.

    Sounds like conjuration to me.

  2. 😂😂😂😂😂

  3. oldbrew says:

    Wikipedia:
    Sealevel change can be attributed to other factors (thermal expansion, ice melting, and mantle convection creating dynamic topography[35]). Over very long timescales, however, it is the result of changes in the volume of the ocean basins which are, in turn, affected by rates of seafloor spreading along the mid-ocean ridges.[36]

    The high sea level that occurred during the Cretaceous Period (144–65 Ma) can only be attributed to plate tectonics since thermal expansion and the absence of ice sheets by themselves cannot account for the fact that sea levels were 100–170 meters higher than today.

    https://en.wikipedia.org/wiki/Mid-ocean_ridge#Impact_on_global_sea_level

  4. ivan says:

    “This means it constantly gets an injection of new material coming from below. The longer it sits on top, the more new material is injected into it and the larger it becomes.”

    Err, if it comes from below doesn’t that mean that over time the earth will be hollow and liable to collapse in on itself, or is there some magic way this material gets replaced in the centre.

    Maybe this whole ‘research’ is just a SF story by wackademics that need to ‘publish or perish’.

  5. hunterson7 says:

    The initial mechanism…was it the planet-reforming/recovering from the collision that created the moon?
    As to the “new crustal material”, it can’t be much, more of an oozing of lighter magma fractions?
    The presentation is silly, like most of “woke” “journalism”. The only thing missing is a reference as to how climate change will make the process worse…

  6. oldbrew says:

    JANUARY 27, 2021
    Geological phenomenon widening the Atlantic Ocean
    by University of Southampton

    An upsurge of matter from deep beneath the Earth’s crust could be pushing the continents of North and South America further apart from Europe and Africa, new research has found.

    The plates attached to the Americas are moving apart from those attached to Europe and Africa by four centimetres per year.

    https://phys.org/news/2021-01-geological-phenomenon-widening-atlantic-ocean.html
    – – –
    Either the Earth is expanding or something else is getting compressed by the same amount?

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