+ Reply to Thread
Results 1 to 6 of 6

Thread: The First Mass Extinction

  1. Link to Post #1
    France On Sabbatical
    Join Date
    7th March 2011
    Location
    Brittany
    Posts
    16,765
    Thanks
    60,315
    Thanked 95,326 times in 15,478 posts

    Default The First Mass Extinction

    Large volcanic eruption may have caused the first mass extinction

    PhysOrg Wed, 17 May 2017 14:09 UTC



    The researchers found Hg enrichments in sedimentary rocks deposited in North America and southern China 445-443 million years ago. Hg enrichments are products of multiple phases of a large igneous province volcanism. This, they say, could have led to the environmental changes that caused the disappearance of many marine animal species. Credit: Kunio Kaiho

    Researchers in the U.S. and Japan say they may have found the cause of the first mass extinction of life on Earth.

    There have been five mass extinctions since the divergent evolution of early animals 600 to 450 million years ago (Figure 1). Volcanic activity was the cause of both the third and fourth, while an asteroid impact led to the fifth. But triggers of the first and second mass extinctions had, until now, been unknown. The new study strongly suggests volcanic activity caused the first mass extinction.

    It occurred at the end of the Ordovician. This age is between the divergence of the Ordovician and land invasion of vascular land plants and animals. Animals in the Ordovician-Silurian comprised marine animals like corals, trilobites, sea scorpions, orthoceras, brachiopods, graptolite, crinoid and jawless fish. Approximately 80 percent of species disappeared at the end of the Ordovician.


    Ordovician-Silurian marine fossils from the museum of Tohoku University. Credit: Kunio Kaiho

    A team led by Dr. David S. Jones of Amherst College and Professor Kunio Kaiho of Tohoku University looked into possible triggers of the first mass extinction. They took sedimentary rock samples from two places—North America and southern China—and analyzed their mercury (Hg) content. They found Hg enrichments coinciding with the mass extinction in both areas. This, they believe, is the product of large volcanic eruptions, because the Hg anomaly was also observed in other large igneous province volcanisms.

    Huge volcanic eruptions can produce sulfate aerosols in the stratosphere. Sulfate aerosols are strong, light-reflecting aerosols, and cause global cooling. This rapid climate change is believed to be behind the loss of marine creatures.

    Kaiho's team is now studying the second mass extinction in the hopes of further understanding the cause and processes behind it.


    Outcrop of the Upper Ordovician studied at Monitor Range in Nevada. Credit: David S. Jones

    Explore further: Recovery after 'great dying' was slowed by more extinctions

    More information:
    Authors: David S. Jones, Anna M. Martini, David A. Fike, Kunio Kaiho, A volcanic trigger for the Late Ordovician mass extinction?: Hg data from South China and Laurentia, Geology, DOI: 10.1130/G38940.1

    Journal reference: Geology
    Provided by: Tohoku University
    "La réalité est un rêve que l'on fait atterrir" San Antonio AKA F. Dard

    Troll-hood motto: Never, ever, however, whatsoever, to anyone, a point concede.

  2. The Following 32 Users Say Thank You to Hervé For This Post:

    Atlas (22nd May 2017), avid (22nd May 2017), bennycog (23rd May 2017), Bill Ryan (22nd May 2017), Billy (22nd May 2017), Bruno (23rd May 2017), Calz (22nd May 2017), Cardillac (22nd May 2017), Daughter of Time (22nd May 2017), DNA (22nd May 2017), earthdreamer (23rd May 2017), enigma3 (22nd May 2017), Ewan (22nd May 2017), fourty-two (23rd May 2017), Foxie Loxie (22nd May 2017), ghostrider (22nd May 2017), Jantje (22nd May 2017), justntime2learn (22nd May 2017), Michelle Marie (22nd May 2017), Nasu (23rd May 2017), Noelle (22nd May 2017), Ol' Roy (23rd May 2017), onevoice (22nd May 2017), pabranno (22nd May 2017), rgray222 (23rd May 2017), seko (23rd May 2017), Sophocles (22nd May 2017), Sunny-side-up (23rd May 2017), The Freedom Train (22nd May 2017), toppy (22nd May 2017), wnlight (22nd May 2017), Zampano (22nd May 2017)

  3. Link to Post #2
    Ecuador Honored, Retired Member. Warren passed on 2 July, 2020.
    Join Date
    28th March 2014
    Location
    Cuenca, Ecuador
    Age
    77
    Posts
    953
    Thanks
    5,175
    Thanked 5,500 times in 864 posts

    Default Re: The First Mass Extinction

    Thank you. Most interesting But there likely were mass extinctions previous to the Ordovician that we do not know about.

  4. The Following 6 Users Say Thank You to wnlight For This Post:

    Bill Ryan (24th October 2019), Bubu (23rd May 2017), Cardillac (22nd May 2017), Foxie Loxie (22nd May 2017), Nasu (23rd May 2017), The Freedom Train (22nd May 2017)

  5. Link to Post #3
    France On Sabbatical
    Join Date
    7th March 2011
    Location
    Brittany
    Posts
    16,765
    Thanks
    60,315
    Thanked 95,326 times in 15,478 posts

    Default Re: The First Mass Extinction

    Quote Posted by wnlight (here)
    [...]
    ... But there likely were mass extinctions previous to the Ordovician that we do not know about.
    Warren... are you playing a "Corey Goode" on me?
    "La réalité est un rêve que l'on fait atterrir" San Antonio AKA F. Dard

    Troll-hood motto: Never, ever, however, whatsoever, to anyone, a point concede.

  6. The Following 4 Users Say Thank You to Hervé For This Post:

    avid (22nd May 2017), Foxie Loxie (22nd May 2017), Nasu (23rd May 2017), The Freedom Train (22nd May 2017)

  7. Link to Post #4
    United States Avalon Member ghostrider's Avatar
    Join Date
    6th February 2011
    Location
    Sand Springs Ok
    Age
    55
    Posts
    7,428
    Thanks
    9,893
    Thanked 28,625 times in 6,628 posts

    Default Re: The First Mass Extinction

    We could be heading for the last extinction ... they say history repeats, the circle of life and all, I hope we survive our technology this time ...
    Raiding the Matrix One Mind at a Time ...

  8. The Following 2 Users Say Thank You to ghostrider For This Post:

    Foxie Loxie (23rd May 2017), Nasu (23rd May 2017)

  9. Link to Post #5
    On Sabbatical
    Join Date
    10th July 2013
    Location
    Project Avalon
    Posts
    3,651
    Thanks
    19,216
    Thanked 16,136 times in 3,214 posts

    Default Re: The First Mass Extinction

    What if a Supervolcano Erupted?

  10. The Following 5 Users Say Thank You to Atlas For This Post:

    Bubu (23rd May 2017), earthdreamer (23rd May 2017), Foxie Loxie (23rd May 2017), ghostrider (23rd May 2017), Nasu (23rd May 2017)

  11. Link to Post #6
    France On Sabbatical
    Join Date
    7th March 2011
    Location
    Brittany
    Posts
    16,765
    Thanks
    60,315
    Thanked 95,326 times in 15,478 posts

    Default Re: The First Mass Extinction

    Mercury in fossilised ferns revealed as hidden driver in mass extinctions

    Barry Keily Cosmos Magazine
    Thu, 24 Oct 2019 18:56 UTC


    Mutated ferns point to a new culprit in prehistoric mass extinctions, researchers say.
    © GEUS

    Bad news loves company. Researchers have discovered that it wasn't just erupting volcanoes, massive amounts of carbon dioxide, oceans full of sulphuric acid, runaway global warming and a thinning ozone layer that caused the end-Triassic mass extinction 201 million years ago.

    It was also large quantities of lethal mercury causing plant life to mutate and die.

    Four out of the five mass extinctions that occurred over the past 600 million years have been linked to huge and prolonged bursts of volcanic activity.

    In the case of the Triassic event - which saw the end of an estimated 40% of land animal genera and 30% of ocean-dwelling groups - there is ample evidence that volcanoes sprang to life across an area known as the Central Atlantic Magmatic Province (CAMP) 100,000 years before the great dying began. It continued, sporadically, for another 700,000.

    Such a profound upheaval causes substantial environmental disruption - including long-lasting spikes in carbon dioxide and sulphur combinations that have been regularly and reliably associated with high levels of animal and plant deaths.

    Now, however, scientists led by Sofie Lindström of the Geological Survey of Denmark and Greenland have identified another nasty: pulsed elevated concentrations of mercury in the ocean and the soil.

    Mercury, write the researchers, is "the most genotoxic element on Earth". That means it doesn't just eventually kill whatever plants or animals it comes into contact with. It also causes mutations within their genomes, resulting in offspring that do not survive.

    To test the contribution of mercury to the end-Triassic mass die-off, Lindström and colleagues examined fossilised fern spores from the period and looked for irregular shapes.

    A proportion of mutation within any species is expected - it is, after all, one of the main drivers of evolution. In the fern species this natural rate of genetic change runs between 3% and 5%.

    The scientists discovered that in spores and pollen collected from some areas in the highly volcanic period leading up to the mass extinction as many as 56% appeared deformed, suggesting very high rates of mutation.

    "As one of the most toxic elements on the planet, mercury can cause both visible injuries and physiological disorders in plants," the researchers write.

    They add that that today "mercury pollution from anthropogenic sources is known to seriously disturb growth and reproductive cycles in plants, causing long-term effects on soil fertility and subsequent severe health issues to animals and human population".

    Around 200 million years ago, of course, there were no anthropogenic sources of mercury - but there is ample evidence that volcanoes pumped out enormous amounts of it.

    Its effect on life on Earth would have been to deliver a double blow. First, plant species would have been severely depleted, with many becoming extinct. Second, the loss of plant matter would have resulted in a very short time in an upstream decrease in the numbers of animals who normally dined on them.

    If lava or atmospheric poisons didn't kill them, it seems, hunger would.

    The research is published in the journal Science Advances.


    A normal fern spore compared with mutated ones from the end-Triassic mass extinction event. © S LINDSTRÖM, GEUS
    "La réalité est un rêve que l'on fait atterrir" San Antonio AKA F. Dard

    Troll-hood motto: Never, ever, however, whatsoever, to anyone, a point concede.

  12. The Following 5 Users Say Thank You to Hervé For This Post:

    Bill Ryan (24th October 2019), Cara (25th October 2019), Franny (25th October 2019), Satori (24th October 2019), Star Mariner (25th October 2019)

+ Reply to Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts