Download Permian-Triassic Extinction “The Mother of all Extinctions”

Permian-Triassic
Extinction
“The Mother of all Extinctions”
Anne Kleinhenz
Permian-Triassic Extinction
 What was it?
The mass extinction at the end of the
Permian that wiped out almost all life
 Took place about 250mya
Paleozoic and Mesozoic Eras
 Took place over a span of 5-10 million
years
When?
 5-10 million years is an abnormally long
time
 Many taxa slowly died out in the
beginning
 Towards the end, extinctions were more
rapid
When?
 Boundary sections in South China show
that 280 out of 329 marine invertebrate
genera disappear within the final 2
conodont zones of the Permian
 In boundary sections preserving a
record of the P-Tr transition, large
numbers of species disappear over few
meters of sediment or less.
How Big?
 Systematic collections show that ~50%
of families, and perhaps as much as
90% of all species known from the late
Permian disappear from the fossil
record during the latest Permian
 Killed about 95% species in oceans
 Marine invertebrates were hit the worst
by extinction
What Died?
 All trilobites
 94% Graptolites
 All Blastoids,
Acanthodians, Rugose
and Tabulate Corals,
Pelycosaurs
 98% Crinozoans
 96% Anthozoans
 96% Brachiopod genera
What Else Died?
 85% Gastropods
 59% Bivalves
 79% Bryozoans
 90% Gastropod genera and
 3 of 16 Gastropod families
 97% Ammonoids
Vertebrates That Died
 Extinction for the
vertebrates was far less
severe than for the
invertebrates
 This has led to less
research and literature
on these organisms being
published
 Tetrapods, amphibians,
reptiles were all very
prominent during this
age
Vertebrates That Died and
Lived
 Amphibians died out as the pools of water in
which they lived in dried up
 Amniota then became dominant
 By Mid-Permian the Therapsids became
dominant
 Archosauriformes were also evolving at the
time, and were one of the few vertebrates to
make it through the extinction and diversify
Vascular plants
 Vascular plants showed no major drop
or change in numbers
 The fossil record shows a gradual
transition from Paleozoic to Mesozoic
floras
 Took place over a period of about 25
million years
Why?
 There are many theories of what
caused one of the larges extinctions in
history:
Volcanism
Impact
Climate Change
Formation of Pangaea
Glaciation
Others
Impact
 There is some
evidence supporting
this theory
 Nickel-rich Layers
 From impact or
heavy-metal rich
mantle-derived lavas
 Shocked quarts
 Bedout Crater in
Australia
Pangaea
 Formed during the Late Permian
 Tectonic movement of the plates had many
side effects
 Most was inland, so weather was hot and dry in
low lying areas, and unseasonable weather
patterns in higher altitudes
 Movement of species and more competition
 Extreme flooding due to glacial melting and
caused reduced land area
Volcanism
 The Siberian Traps
 Volcanoes cover approximately 2,000,000 km2 in
Siberia (greater area than Europe)
 Eruptions lasted at full intensity for about a million
years
Volcanism
 The Siberian Traps has climate altering
potential by the emission of ash and gases.
 Initially sulfur aerosols and volcanic ash
block out sunlight, causing rapid cooling.
 Ash and sulfur aerosols can remain in the
upper atmosphere for 100's to 1000's of
years which would be enough to cause a
significant glaciation.
 At the end of the Permian period the biggest
ever drop in sea level in history occurred,
indicating large scale glaciation.
Volcanism
 Greenhouse gases warm the climate by
allowing sunlight to pass through
 Heat reflected by the Earth itself cannot
penetrate the atmosphere so is
retained.
 Greenhouse gases stay in the
atmosphere much longer so their
climate changing effects can last for
millions of years.
Another Volcanic Theory
 PBS Nova Special
Linked Theories
 “The Pangean super continent led to many
changes in the shape of the land, glaciation
patterns and climate, which in turn altered
sea level and salinity of the oceans. These
affects are often interlinked. The presence of
Pangaea helped to initiate extreme
environments, and along with other evidence,
such as volcanism and impact, led to the
biggest extinction seen in the history of
Earth.” (http://palaeo.gly.bris.ac.uk/Palaeofiles/Permian/pangea.html)
Bibliography
 http://palaeo.gly.bris.ac.uk/Palaeofiles/Permian/pangea.html
 http://www.geocities.com/earthhistory/permo.htm
 http://www.earth.rochester.edu/ees207/Mass_Ext/higgins_mass




4.html
http://www.pbs.org/wgbh/nova/sciencenow/3318/01.html
Benton. "How to kill(almost) all life: the end-Permian extinction
event." Trends in Ecology 18.7 (2003): 358.
Berner. "Examination of hypotheses for the Permo-Triassic
boundary extinction by carbon cycle modeling." Proceedings of
the National Academy of Sciences 99.7 (2002): 4172.
Kidder, David L. and Thomas R. Worsley. "Causes and
consequences of extreme Permo-Triassic warming to globally
equable climate and relation to the Permo-Triassic extinction
and recovery." Palaeogeography, Palaeoclimatology,
Palaeoecology 203.3-4 (2004), 207-237.