The Permo - Triassic Mass Extinction

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The Permo - Triassic Mass Extinction

• Manuel Queisser

2
Outline

• What happened?
• Methods of resolution
• A profound theory From icehouse to hothouse
• - The extinction process
• - Recovery
• - Summary
• Discussion

3
What happened?

• Maybe the largest extinction of the Phanerozoic

4
What happened?

• Maybe the largest extinction of the Phanerozoic
• 85 of all marine species and 70 of all
  terrestrial species died out

5
What happened?

• Maybe the largest extinction of the Phanerozoic
• 85 of all marine species and 70 of all
  terrestrial species died out
• E.g. trilobites, rugose corals, pelycosaurs
  vanished
• E.g. brachiopods, ammonoids substantially reduced

6
What happened?

• 320 Ma ago (late Carboniferous) forests developed
  - CO2 drawdown (level as high as today)

7
What happened?

• 320 Ma ago (late Carboniferous) forests developed
  - CO2 drawdown (level as high as today)
• Pangea assembled - little volcanic CO2 output

8
What happened?

• 320 Ma ago (late Carboniferous) forests developed
  - CO2 drawdown (level as high as today)
• Pangea assembled - little volcanic CO2 output
• 4th great glaciation took place

9
What happened?

• 320 Ma ago (late Carboniferous) forests developed
  - CO2 drawdown (level as high as today)
• Pangea assembled - little volcanic CO2 output
• 4th great glaciation took place
• However, in Permian warming occured

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Outline

• What happened?
• Methods of resolution
• A profound theory From icehouse to hothouse
• - The extinction process
• - Recovery
• - Summary
• Discussion

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Methods of resolution- Cosmic impact

• Consistent with abruptness (lt 1Ma)

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Methods of resolution- Cosmic impact

• Consistent with abruptness (lt 1Ma)
• Iridium findings not convincing enough

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Methods of resolution- Cosmic impact

• Consistent with abruptness (lt 1Ma)
• Iridium findings not convincing enough
• Dust layer could have also been created by
  volcanism

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Methods of resolution- Volcanism

• Volcanism in Siberia (1-3 Mio km3) produced
  toxicity and enhanced cooling, then caused
  greenhouse effect

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Methods of resolution- Volcanism

• Volcanism in Siberia (1-3 Mio km3) produced
  toxicity and enhanced cooling, then caused
  greenhouse effect
• Characteristic ash layer in South China (shocked
  quartz, acidic,)
• Consistent with drop in 13C relative and O18

Meishan section, south China. Bowring et al. 1998
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Methods of resolution- Volcanism

• Volcanism in Siberia (1-3 Mio km3) produced
  toxicity and enhanced cooling, then caused
  greenhouse effect
• Characteristic ash layer in South China (shocked
  quartz, acidic,)
• Consistent with drop in 13C relative and O18

Kidder Worlsley, 2004
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Methods of resolution- Volcanism

• critics say this all is not enough to explain the
  huge 13C drop
• Could have never triggered a mass extinction on
  its own

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Methods of resolution- Formation of Pangea

• reduced spreading and number of marine provinces
  (shelves), which regressed species

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Methods of resolution- Formation of Pangea

• reduced spreading and number of marine provinces
  (shelves), which regressed species
• Explains only marine extinction

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Methods of resolution- Formation of Pangea

• reduced spreading and number of marine provinces
  (shelves), which regressed species
• Explains only marine extinction
• Occurred in early/mid Permian, before mass
  extinction

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Methods of resolution- Salinity drop

• First formed by Beurlen in 1956

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Methods of resolution- Salinity drop

• First formed by Beurlen in 1956
• Evidence that mainly stenohaline organisms
  suffered

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Methods of resolution- Salinity drop

• First formed by Beurlen in 1956
• Evidence that mainly stenohaline organisms
  suffered
• Among other reasons brine-reflux hypothesis

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Methods of resolution- Salinity drop

• First formed by Beurlen in 1956
• Evidence that mainly stenohaline organisms
  suffered
• Among other reasons brine-reflux hypothesis
• Evaporation deposited dense salt brines that
  sank to the ocean bottom and left the surface
  water salt free (drinkable)

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Methods of resolution- Salinity drop

• First formed by Beurlen in 1956
• Evidence that mainly stenohaline organisms
  suffered
• Among other reasons brine-reflux hypothesis
• Evaporation deposited dense salt brines that
  sank to the ocean bottom and left the surface
  water salt free (drinkable)
• Consistent with a climate warming

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Outline

• What happened?
• Methods of resolution
• A profound theory From icehouse to hothouse
• - The extinction process
• - Recovery
• - Summary
• Discussion

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From icehouse to hothouse

• All this factors alone seem to be too weak to
  cause such a devastating event

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From icehouse to hothouse

• All this factors alone seem to be too weak to
  cause such a devastating event
• System of feedbacks Theory of D. Kidder and Th.
  Worsley, Ohio State University

29
Outline

• What happened?
• Methods of resolution
• A profound theory From icehouse to hothouse
• - The extinction process
• - Recovery
• - Summary
• Discussion

30
From icehouse to hothouse

• 320 Ma ago (late Carboniferous) forests developed
  - CO2 drawdown (level as high as today)
• Pangea assembled - little volcanic CO2 output
• 4th great glaciation took place

31
From icehouse to hothouse

• 320 Ma ago (late Carboniferous) forests developed
  - CO2 drawdown (level as high as today)
• Pangea assembled - little volcanic CO2 output
• 4th great glaciation took place
• Cessation of orogeny lowered silicate weathering
  - kickoff

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From icehouse to hothouse

• In the mid Permian volcanism in Siberia outpoured
  CO2

Kidder Worsley, 2004
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From icehouse to hothouse

• In the mid Permian volcanism in Siberia outpoured
  CO2
• Interior of waste Pangea already hot and arid

Kidder Worsley, 2004
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From icehouse to hothouse

• In the mid Permian volcanism in Siberia outpoured
  CO2
• Interior of waste Pangea already hot and arid
• Now methane hydrates from ocean bottom melted

Kidder Worsley, 2004
35
From icehouse to hothouse

• warming more latent heat transfer
• warming of high latitudes

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From icehouse to hothouse

• warming more latent heat transfer
• warming of high latitudes meridional
  temp. gradient weakened

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From icehouse to hothouse

• warming more latent heat transfer
• warming of high latitudes meridional
  temp. gradient weakened less advection and
  further drying of Pangea

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From icehouse to hothouse

• warming more latent heat transfer
• warming of high latitudes meridional
  temp. gradient weakened less advection and
  further drying of Pangea
• forests shrink withdraw to higher
  latitudes

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From icehouse to hothouse

• warming more latent heat transfer
• warming of high latitudes meridional
  temp. gradient weakened less advection and
  further drying of Pangea
• forests shrink withdraw to higher
  latitudes CO2 burial and weathering
  decreases, less nutrients for plankton (positive
  feedback), dead material oxidized, O2 drawdown
  

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From icehouse to hothouse

• The Searing of Pangea

Kidder Worsley, 2004
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From icehouse to hothouse

• What happened in the oceans?

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From icehouse to hothouse

• What happened in the oceans?
• - like in atmosphere O2 content decreased
  (anoxia)

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From icehouse to hothouse

• What happened in the oceans?
• - like in atmosphere O2 content decreased
  (anoxia) HOW?

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From icehouse to hothouse

• warming ice shields melt

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From icehouse to hothouse

• warming ice shields melt
• weaken thermohaline circulation

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From icehouse to hothouse

• warming ice shields melt
• weaken thermohaline circulation
• cold, O2 rich bottom water substituted by
• warmer, saline, anoxic water (WSBW),
• due to enhanced evaporation,
• possibly released the methane hydrates
• (another positive feedback)

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From icehouse to hothouse
Kidder Worsley, 2004
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From icehouse to hothouse

• In late Permian last forests vanished, increased
  feedbacks (lessened O2)

Kidder Worsley, 2004
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From icehouse to hothouse

• In late Permian last forests vanished, increased
  feedbacks (lessened O2)
• CO2 level 8 times of todays level

Kidder Worsley, 2004
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From icehouse to hothouse

• In late Permian last forests vanished, increased
  feedbacks (lessened O2)
• CO2 level 8 times of todays level
• Average ocean temp. doubled to 30 deg. C in this
  model

Kidder Worsley, 2004
51
Outline

• What happened?
• Methods of resolution
• A profound theory From icehouse to hothouse
• - The extinction process
• - Recovery
• - Summary
• Discussion

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Recovery

• Unusually long (5 Ma)

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Recovery

• Unusually long (5 Ma)
• Possible reasons
• - strong system of feedbacks

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Recovery

• Unusually long (5 Ma)
• Possible reasons
• - strong system of feedbacks
• - lots of rotting vegetation methane

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Recovery

• Unusually long (5 Ma)
• Possible reasons
• - strong system of feedbacks
• - lots of rotting vegetation methane
• - interior of Pangea still very hot and arid,
• no forests hard to recover

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Recovery

• However moist, warm high latitudes good for
  chemical weathering and probably the first place
  for conifers to reconquer

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Recovery

• However moist, warm high latitudes good for
  chemical weathering and probably the first place
  for conifers to reconquer
• atmospheric CO2 decreases, more
  nutrients available in ocean, increased O2
  production and CO2 drawdown by phytoplankton

58
Outline

• What happened?
• Methods of resolution
• A profound theory From icehouse to hothouse
• - The extinction process
• - Recovery
• - Summary
• Discussion

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Rough Summary

• Pangea assembled, less chemical weathering (less
  weatherable silicate rock)

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Rough Summary

• Pangea assembled, less chemical weathering (less
  weatherable silicate rock)
• Warming

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Rough Summary

• Pangea assembled, less chemical weathering (less
  weatherable silicate rock)
• Warming
• Siberian trap volcanism

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Rough Summary

• Pangea assembled, less chemical weathering (less
  weatherable silicate rock)
• Warming
• Siberian trap volcanism
• More warming

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Rough Summary

• Pangea assembled, less chemical weathering (less
  weatherable silicate rock)
• Warming
• Siberian trap volcanism
• More warming
• Feedbacks lowered O2 in ocean atmosphere

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Rough Summary

• Pangea assembled, less chemical weathering (less
  weatherable silicate rock)
• Warming
• Siberian trap volcanism
• More warming
• Feedbacks lowered O2 in ocean atmosphere
• Pangea bleak, hot and dry, oceans anoxic and warm

65
Rough Summary

• Pangea assembled, less chemical weathering (less
  weatherable silicate rock)
• Warming
• Siberian trap volcanism
• More warming
• Feedbacks lowered O2 in ocean atmosphere
• Pangea bleak, hot and dry, oceans anoxic and warm
• Recovery at higher latitudes by increasing
  weathering

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Outline

• What happened?
• Methods of resolution
• A profound theory From icehouse to hothouse
• - The extinction process
• - Recovery
• - Summary
• Discussion

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Discussion

• Model is consistent with the most of the
  evidences and possible causes of the extinction
  (e.g. 13C drop, deep water anoxia, Siberian
  volcanism)

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Discussion

• Model is consistent with the most of the
  evidences and possible causes of the extinction
  (e.g. 13C drop, deep water anoxia, Siberian
  volcanism)
• There are questions left

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Discussion

• What exactly caused the huge 13C drop?

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Discussion

• What exactly caused the huge 13C drop?
• What is its magnitude?

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Discussion

• What exactly caused the huge 13C drop?
• What is its magnitude?
• Were the marine and terrestrial extinction
  cotemporary?

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Discussion

• What exactly caused the huge 13C drop?
• What is its magnitude?
• Were the marine and terrestrial extinction
  cotemporary?
• Was the extinction cotemporary across the planet?

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Discussion

• What exactly caused the huge 13C drop?
• What is its magnitude?
• Were the marine and terrestrial extinction
  cotemporary?
• Was the extinction cotemporary across the planet?
• When exactly started the extinction (241 250 Ma
  BP)?

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Discussion

• Other evidences are contradictory to this model,
  e.g.

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Discussion

• Extinction was gradually rather than abruptly
  (Clark et al., 1985 and Magaritz et al., 1988)
  sections in the Alps show gradual change in the
  C-13 content of marine organisms across the PTB

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Discussion

• Extinction was gradually rather than abruptly
  (Clark et al., 1985 and Magaritz et al., 1988)
  sections in the Alps show gradual change in the
  C-13 content of marine organisms across the PTB
  
• to volcanic (or impact?) dust layer

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Discussion

• There was no salinity drop but an increase (Bowen
  in 1968) salinity level 20 of todays level
  due to large evaporation and deposition

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Discussion

• There was no salinity drop but an increase (Bowen
  in 1968) salinity level 20 of todays level
  due to large evaporation and deposition
• to salinity drop proposed by model

79
Discussion

• There was no salinity drop but an increase (Bowen
  in 1968) salinity level 20 of todays level
  due to large evaporation and deposition
• to salinity drop proposed by model
• Others (Erwin) say there are no consistent
  evidences for a salinity change as a cause,
  because not all stenohaline organisms suffered

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Discussion

• There was no global warming but a cooling!

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Discussion

• There was no global warming but a cooling!
• Sedimentary evidences for drying and glaciation,
  such as dunes, evaporites in mid latitudes and
  glacial deposits in polar zones, reduced
  carbonate limestones in tropics due to cooling

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Discussion

• There was no global warming but a cooling!
• Sedimentary evidences for drying and glaciation,
  such as dunes, evaporites in mid latitudes and
  glacial deposits in polar zones, reduced
  carbonate limestones in tropics due to cooling
• Siberian volcanism could have had a cooling
  effect (aerosols) instead of warming

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Discussion

• Nobody knows for sure the cause(s) for the mass
  extinction