Volcano eruptions triggered mass extinction before the age of dinosaurs 200 million years ago

Posted: June 21, 2017 by oldbrew in atmosphere, Geology, History, volcanos
Tags: ,


Is there a contradiction in this IB Times report? First it says volcanism causes cooling, then we’re told the resulting volcanic CO2 could have caused warming.

High concentration of mercury identified in ancient sediments suggest that large-scale episodes of volcanism coincided with the end-Triassic mass extinction around 201 million years ago.

It is likely that these huge pulses of volcanic activity led to great environmental perturbations, leading to the extinction of many species living on Earth at the time and setting the scene for the dawn of the dinosaurs.

Previous studies had already shown that volcanic activity was happening around the time of the extinction and there was some evidence for an increase in the concentration of carbon dioxide (CO2) in the atmosphere.


Scientists thought that volcanic gases such as CO2 might have been an important contributor to the extinction event.

However, the global extent of the volcanic fluctuations at the end of the Triassic remained unknown and more research was needed to confirm the role of volcanic CO2.

Mercury levels

In a study now published in the journal PNAS, scientists have examined sediments and volcanic rocks which had formed around the end of the Triassic, looking for fluctuations in mercury – an important element released in volcanic gas.

“You want to look for something like mercury that is not too abundant in the earth’s surface reservoirs and that comes out of volcanoes in significant quantities. That way the signals from volcanism are easier to spot. Mercury also has a sufficiently long atmospheric lifetime that it stays in the atmosphere long enough to get far enough away from the volcano itself, to actually be seen in sediments around the world,” study author Tamsin Mather of Oxford University, told IBTimes UK.

At five of the six locations studied, the researchers identified pulses of elevated mercury in the sediment layers, in strata formed at the end-Triassic extinction and between it and the Triassic–Jurassic boundary, separated by approximately 200,000 years. These elevated mercury concentrations imply repeated episodes of large-scale volcanism over that time.

Continued here.

Talkshop note – the closing paragraph starts:
“Warming and cooling due to volcanic activity can have a range of potential knock-on effects on Earth.”

Comments
  1. Bob Greene says:

    Cold and hot mercury does it?

  2. Richard111 says:

    Some reports recently about Yellowstone activity. Considered minor but worth reporting. Hmmm…

  3. oldbrew says:

    ‘Volcanism affects the environment in quite a number of ways and it is still not yet fully understood how it triggers mass extinction events. However, scientists do know that a big eruption can cool the planet down and that it also releases a big amount of CO2.’

    So they have direct evidence that volcanism can produce a lot of CO2 and that volcanism can cause cooling of the planet. But no evidence that CO2 from volcanism causes any warming?

    ‘Single eruptions really don’t put out enough CO2 to cause significant changes to the atmosphere, but if you have large scale volcanism going on for a very prolonged period of time, you may end up warming the planet up’

    Speculation not science?

  4. ivan says:

    Speculation not science?

    oldbrew, they have to justify their grant money somehow. If they didn’t have that in someone might think they were unbelievers.

  5. oldbrew says:

    ivan – this is the problem, for me at least…

    Volcanoes and their effect on climate
    David Viner & Phil Jones

    It has been known for some time that explosive volcanic eruptions can have a major influence on global and regional climate. The most well known eruption of recent times was Tambora, Indonesia, which exploded in 1815. The following summer became known as the “the year without a summer” in many parts of the Northern Hemisphere.
    . . .
    Earlier work, from the 1960s onwards, suggested that when eruption clouds reach the lower stratosphere (about 20-25km aloft) the dust spreads around over subsequent months forming a veil over the Earth. The veil slightly reduces the amount of incoming solar radiation reaching the surface, causing a cooling.
    . . .
    These data show that the 20th century has seen more eruptions than some centuries of this millennium but less than in the 16th/17th/19th centuries. Volcanoes have probably, therefore, made a contribution to the cooler temperatures of these centuries, relative to the 20th century.
    [bold added]

    http://www.cru.uea.ac.uk/documents/421974/1295957/Info+sheet+%2313.pdf
    – – –
    Everything points to cooling all the way with explosive eruptions.
    They even imply that 20th C ‘warming’ is partly ‘lack of volcanic cooling’.

  6. ivan says:

    oldbrew, not only you but I imagine all of us that don’t believe in the warmest religion.

    No matter what the real data says somehow it must follow the party line even if all they can do is add ambiguous throwaway statements at the end of papers.

    What they are going to do when real cooling arrives doesn’t bear thinking about.

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