Download The Permian-Triassic Mass Extinction

The Permo - Triassic Mass
Extinction
Manuel Queisser
Outline
 What happened?
 Methods of resolution
 A profound theory: From icehouse to hothouse
- The extinction process
- Recovery
- Summary
 Discussion
What happened?
Maybe the largest extinction of the
Phanerozoic
What happened?
Maybe the largest extinction of the
Phanerozoic
85% of all marine species and 70% of all
terrestrial species died out
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
What happened?
320 Ma ago (late Carboniferous) forests
developed - CO2 drawdown (level as high
as today)
What happened?
320 Ma ago (late Carboniferous) forests
developed - CO2 drawdown (level as high
as today)
Pangea assembled - little volcanic CO2
output
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
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
Outline
What happened?
Methods of resolution
A profound theory: From icehouse to
hothouse
- The extinction process
- Recovery
- Summary
Discussion
Methods of resolution- Cosmic impact
Consistent with abruptness (< 1Ma)
Methods of resolution- Cosmic impact
Consistent with abruptness (< 1Ma)
Iridium findings not convincing enough
Methods of resolution- Cosmic impact
Consistent with abruptness (< 1Ma)
Iridium findings not convincing enough
Dust layer could have also been created
by volcanism
Methods of resolution- Volcanism
Volcanism in Siberia (1-3 Mio km3)
produced toxicity and enhanced cooling,
then caused greenhouse effect
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
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
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
Methods of resolution- Formation of
Pangea
reduced spreading and number of marine
provinces (shelves), which regressed
species
Methods of resolution- Formation of
Pangea
reduced spreading and number of marine
provinces (shelves), which regressed
species
Explains only marine extinction
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
Methods of resolution- Salinity drop
First formed by Beurlen in 1956
Methods of resolution- Salinity drop
First formed by Beurlen in 1956
Evidence that mainly stenohaline
organisms suffered
Methods of resolution- Salinity drop
First formed by Beurlen in 1956
Evidence that mainly stenohaline
organisms suffered
Among other reasons: brine-reflux
hypothesis:
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)
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
Outline
What happened?
Methods of resolution
A profound theory: From icehouse to
hothouse
- The extinction process
- Recovery
- Summary
Discussion
From icehouse to hothouse
All this factors alone seem to be too weak
to cause such a devastating event
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
Outline
What happened?
Methods of resolution
A profound theory: From icehouse to
hothouse
- The extinction process
- Recovery
- Summary
Discussion
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
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
From icehouse to hothouse
 In the mid Permian
volcanism in Siberia
outpoured CO2
Kidder & Worsley, 2004
From icehouse to hothouse
 In the mid Permian
volcanism in Siberia
outpoured CO2
 Interior of waste
Pangea already hot
and arid
Kidder & Worsley, 2004
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
From icehouse to hothouse
…warming
more latent heat transfer
warming of high latitudes
From icehouse to hothouse
…warming
more latent heat transfer
warming of high latitudes
meridional
temp. gradient weakened
From icehouse to hothouse
…warming
more latent heat transfer
warming of high latitudes
meridional
temp. gradient weakened
less
advection and further drying of Pangea
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
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
From icehouse to hothouse
The Searing of Pangea:
Kidder & Worsley, 2004
From icehouse to hothouse
What happened in the oceans?
From icehouse to hothouse
What happened in the oceans?
- like in atmosphere O2 content decreased
(anoxia)
From icehouse to hothouse
What happened in the oceans?
- like in atmosphere O2 content decreased
(anoxia) – HOW?
From icehouse to hothouse
…warming
ice shields melt
From icehouse to hothouse
…warming
ice shields melt
weaken thermohaline circulation
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)
From icehouse to hothouse
Kidder & Worsley, 2004
From icehouse to hothouse
 In late Permian last
forests vanished,
increased feedbacks
(lessened O2)
Kidder & Worsley, 2004
From icehouse to hothouse
 In late Permian last
forests vanished,
increased feedbacks
(lessened O2)
 CO2 level 8 times of
today’s level
Kidder & Worsley, 2004
From icehouse to hothouse
 In late Permian last
forests vanished,
increased feedbacks
(lessened O2)
 CO2 level 8 times of
today’s level
 Average ocean temp.
doubled to 30 deg. C
in this model
Kidder & Worsley, 2004
Outline
What happened?
Methods of resolution
A profound theory: From icehouse to
hothouse
- The extinction process
- Recovery
- Summary
Discussion
Recovery
Unusually long (5 Ma)
Recovery
Unusually long (5 Ma)
Possible reasons:
- strong system of feedbacks
Recovery
Unusually long (5 Ma)
Possible reasons:
- strong system of feedbacks
- lots of rotting vegetation – methane
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
Recovery
However: moist, warm high latitudes good
for chemical weathering and probably the
first place for conifers to reconquer
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
Outline
What happened?
Methods of resolution
A profound theory: From icehouse to
hothouse
- The extinction process
- Recovery
- Summary
Discussion
Rough Summary
Pangea assembled, less chemical
weathering (less weatherable silicate rock)
Rough Summary
Pangea assembled, less chemical
weathering (less weatherable silicate rock)
Warming
Rough Summary
Pangea assembled, less chemical
weathering (less weatherable silicate rock)
Warming
Siberian trap volcanism
Rough Summary
Pangea assembled, less chemical
weathering (less weatherable silicate rock)
Warming
Siberian trap volcanism
More warming
Rough Summary
Pangea assembled, less chemical
weathering (less weatherable silicate rock)
Warming
Siberian trap volcanism
More warming
Feedbacks lowered O2 in ocean &
atmosphere
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
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
Outline
What happened?
Methods of resolution
A profound theory: From icehouse to
hothouse
- The extinction process
- Recovery
- Summary
Discussion
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)
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…
Discussion
What exactly caused the huge 13C drop?
Discussion
What exactly caused the huge 13C drop?
What is its magnitude?
Discussion
What exactly caused the huge 13C drop?
What is its magnitude?
Were the marine and terrestrial extinction
cotemporary?
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?
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)?
Discussion
Other evidences are contradictory to this
model, e.g.:
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
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
Discussion
There was no salinity drop but an
increase (Bowen in 1968): “salinity level 20%
of today’s level” due to large evaporation
and deposition
Discussion
There was no salinity drop but an
increase (Bowen in 1968): “salinity level 20%
of today’s level” due to large evaporation
and deposition
to salinity drop proposed by model
Discussion
 There was no salinity drop but an increase
(Bowen in 1968): “salinity level 20% of today’s 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
Discussion
There was no global warming but a
cooling!
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
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
Discussion
Nobody knows for sure the cause(s) for
the mass extinction