THE PERMIANTRIASSIC EXTINCTION

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THE PERMIAN-TRIASSIC EXTINCTION
Samantha Mathwig Konny Kwong
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• 250 million years ago
• At the end of the Permian period and the start of
  the Triassic
• Seen as the most catastrophic mass-distinction
  out of all 5 known
• Nick-named the Great Dying of animals and plants

THE PERMIAN-TRIASSIC EXTINCTION
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• 90-96 of Earths marine life was killed
• Can see through studying sedimentary zones in
  China that 280 out of 329 marine invertebrate
  genera disappeared during period
• 70 of Earths land life was killed
• At time included reptiles, amphibians, insects,
  and plants
• 8 out of 9 insect orders became extinct

THE PERMIAN-TRIASSIC EXTINCTION (cont.)
So how do we know this?
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Fossil Evidence of Extinction
Fossil records show that.
-Trilobites, that managed to survive for 300
million years, were killed off during the P-T
-Rugose corals, another popular form of life,
also died off
-sessile filter feeders did not become extinct,
however there were significant fewer amounts
found during and after the P-T extinction
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Fossil Evidence of Extinction (cont.)

• In general, species with shells of calcium
  carbonate were killed, while creatures with
  chitin (thin) shells or no shells were more
  likely to survive
• Thin shells allowed them to control their
  calcification better

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• So, what could have caused such a massive
  extinction?

Theory 1 Impact Theory 2 Volcanic
Activity Theory 3 Pangaea
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Theory 1 Impact
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What is the Permian-Triassic Boundary?
Theory 1 Impact (cont.)

• Difference in rock layers help draw boundary
  between the Permian Period and the Triassic
  Period (which also marks the boundary between the
  Paleozoic Era and the Mesozoic Era)
• The extinction forms the boundary between the two
  geological time periods.

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Detection of fullerenes within the P-Tr boundary
level
Theory 1 Impact (cont.)

• Carbon allotropes, composed entirely of carbon
• these molecules have the ability to trap noble
  inert gases such as He, Ne, and Ar
• studying a rocks composition of the above gases
  can tell its origin
• specifically, they examined the rocks 3He/4He,
  20Ne/22Ne and 3He/36Ar ratios
• Solar signature contrasts with planetary
  signature
•  
• Space
  Earth
• 3He/4He ratio 3.131024 3 He/4He
  ratio 1.431024
• 20Ne/22Ne ratio 12.5
  20Ne/22Ne ratio 8.0

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Theory 1 Impact (cont.)

• No fullerenes were found in sediments above and
  below the Permian-Triassic Boundary.
• consistent with results on other known
  impact-related boundaries like the
  Cretaceous-Tertiary boundary

The Allende meteorite showing many fullerenes
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Where were they found?

• Meishan, China
• Sasayama, Japan

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Other event markers
Theory 1 Impact (cont.)

• Shocked quartz- found just above the Gondwana
  (southern supercontinent resulting from breakup
  of Pangaea) coal layer that ended the Permian
  Era.

-Normal quartz is orderly and crystalline.
-Notice scratches indicating deformation.
-Produced under intense pressures. -First
discovered after underground nuclear bomb testing
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Theory 1 Impact (cont.)
In fact

• Both the Ir spike layer and the
• shocked quartz layer contain anomalous 13C
  (approximately -40)
• Negative shift release of
• 13C-depleted carbon into the atmosphere
• Suggests a severe
• disruption to the normal plant biomass
  (approximately
• -27)

• Iridium spike during late Permian-
  coincides with last occurrence of the
  Glossopteris flora

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Theory 2 Volcanic Activity
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Siberian Traps
Theory 2 Volcanic Activity

• Largest chain of volcanic eruptions in Earth
  history
• Result of an immense mantle plume giant pulse of
  heat that rises towards the surface from the
  core/mantle boundary
• believed to be part of a cooling mechanism for
  the core, but not fully understood

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• The Siberian flood basalts extend from the Ural
  Mountains to Lake Baikal
• Covered area 2/3 the size of the United States
• Ranging in thickness from 100m to 3,000m
  extending up to 6,500m thick
• At least 23, 106 km3 of initial volume remain
  today

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Coincidence?
Theory 2 Volcanic Activity (cont.)

• Laser-heating 40Ar/39Ar data show bulk of these
  basalts was erupted over short time interval of
  900,000 800,000 years
• Siberian 249 1 million years ago
• Permian/Triassic Extinction 248.2 4.8 million
  years ago

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Effects
Theory 2 Volcanic Activity (cont.)

• DIRECT climatic cooling from sulphuric acid
  aerosols, greenhouse warming from CO2 and SO2
  gases and acid rain.
• Basaltic magmas are rich in dissolved
  sulphur, and sulphuric acid aerosols are injected
  into the stratosphere by convective plumes

INDIRECT changes in ocean chemistry,
circulation, and oxygenation.
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Theory 2 Volcanic Activity (cont.)
In Perspective

• The largest eruption in historic memory Iceland
  (1783-84).
• 12 cubic km of lava onto the island
• The poisonous gases given out killed most of the
  islands crops and foliage and lowering global
  temps by about 1 degree Celsius.
• Siberian Traps erupted about 3 million cubic km!

Rows of lava cones from Laki lava flow
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Theory 2 Volcanic Activity (cont.)
Combination of impact and volcanism?
Perhaps impact-generated seismic waves triggered
a mantle plume and thus flood basalt volcanism
around impact site
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Theory 3 Pangaea
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Theory 3 Pangaea (cont.)

• Continents had recently assembled together into a
  single land mass known as Pangaea
• this would have created a decrease in range of
  shallow aquatic environments
• Exposed the once-protected and isolated creatures
  who lived on the continental shelves to new
  predators
• Most likely most smaller ecosystems would not be
  able to survive such change

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Theory 3 Pangaea (cont.)

• Also this supercontinent may have disrupted
  the circulation of the seawater, making the
  oceans stagnant
• this would have lead to a depletion of oxygen in
  the water as well as high concentrations of
  dissolved carbon dioxide collected in the bottom
  of the ocean
• This would have created drastic and
  potentially-harmful changes in the ocean for all
  marine life
• But how does this affect land life?

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Theory 3 Pangaea (cont.)

• Had sea-level been affected, the anoxic
  (oxygen-lacking) water would spill onto the
  continental shelves, having a drastic impact on
  land life
• But what could have affected sea-level?

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Recovery

• Very slow recovery period after such huge
  extinction
• For millions of years, there were no reefs and no
  coal beds
• Early Triassic rocks give evidence of completely
  undisturbed marine sediments
• Eventually, the first dinosaurs began to arise
• Other mammals and amphibians followed

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Works Cited

• http//www.lpi.usra.edu/meetings/lpsc2003/pdf/1490
  .pdf
• http//srs.dl.ac.uk/Annual_Reports/AnRep02_03/lac.
  htm
• http//www.ch.ic.ac.uk/local/projects/unwin/Fuller
  enes.html
• http//www.geolsoc.org.uk/gsl/education/flood_basa
  lts_1
• http//www.liebertonline.com/doi/pdfplus/10.1089/1
  53110703321632435
• http//www.liebertonline.com/doi/pdfplus/10.1089/1
  53110703321632426
• http//www.liebertonline.com/doi/pdfplus/10.1089/1
  53110703321632480
• http//astrobiology.nasa.gov/?qpermianextinction
  lall
• http//www.dinoextinct.com/page12.htm
• http//www.economicexpert.com/a/Permianextinction
  .htm