Extinction: the Great Dying at the Permo-Triassic Boundary

Question 1

“Age of Carbon”

Answer 1

• during the Carboniferous period

- due to lycopod trees and other organic matter falling in to swamps and becoming buried (high production of coal)

Question 2

Photosynthesis

Answer 2

CO2 + H2O = CH2O + O2

Question 3

Respiration Cycle

Answer 3

CH2O + O2 = CO2 + H2O

Question 4

Carbon Cycle During the Carboniferous Period

Answer 4

• ocean surface and atmosphere exchange gases and CO2 a lot
• plants take up atmospheric CO2
• most plants become buried (CO2 is preserved)

Question 5

Relation between Organic Carbon Burial (Coal Swamps) and Atmospheric CO2

Answer 5

• reduces oxidation of organic carbon and return flux CO2 to the atmosphere
• reduces greenhouse gas warming and temperatures drop

Question 6

What is Gondwanaland?

Answer 6

the part of Pangea that lies within the Southern Hemipshere

Question 7

What is fossil evidence for Gondwanaland?

Answer 7

• glossopteris fossils (tongue leaves) and other fossils found on all continents that suggest they were once all connected

Question 8

What does it mean when photosynthesis “fractionates” carbon isotopes?

Answer 8

During photosynthesis, plants will preferentially take in 12C rather that 13C because it is lighter and can be used quicker.

Thus, the organic matter and coal are depleted of 13C (the heavier isotope)

Question 9

How do carbon isotopes (13C/12C) in marine carbonates (limestone) change during the Carboniferous?

Answer 9

The carbon isotope ratio increases

Question 10

Why do carbon isotopes (13C/12C) in marine carbonates (limestone) change during the Carboniferous?

Answer 10

Due to the burial of organic material (enriched in 12C and depleted of 13C)

Question 11

What does this (the change in Carbon Isotope Ratio) tell us about the burial of Organic C and Atmospheric CO2 levels?

Answer 11

more burial of 13C-depleted organic carbon will result in a reduction in atmospheric CO2 levels

Question 12

Background Extinction

Answer 12

typical turnover and replacement

Question 13

Mass Extinction (how is it identified)?

Answer 13

a. ) magnitude must be very great
b. ) duration is relatively brief (few million years or less)
c. ) the influence must be global

Question 14

When were the FIVE major mass extinctions during the Phanerozoic?

Answer 14

1. ) End-Ordovician
2. ) Late Devonian
3. ) End-Permian
4. ) Late-Triassic
5. ) Late-Cretaceous

Question 15

When did the “Great Dying” occur?

Answer 15

during the end of the Paleozoic era (Permo-Triassic Boundary / End Permian)

Question 16

Main victims of the “Great Dying”

Answer 16

• hella marine invertabrates
• trilobites
• articulate brachiopods
• 2 major coral groups
• sea scorpions

Question 17

The Most likely cause of the “Great Dying”?

Answer 17

Siberian Traps (volcanism and emissions of vast amounts of CO2)

• more CO2 causes global warming which causes ocean acidification

Question 18

How do stable Carbon isotope ratios (13C/12C) change during the “Great Dying”?

Answer 18

• drop in 13C/12C ratio due to the excessive release of 12C
• because plants took in a ton of 12C with burial as they turned to coal when the volcanoes burned them it released all the 12C back in to the atmosphere

Question 19

What does this (change in carbon isotope ratios) signify?

Answer 19

• plants took in hella 12C when they were buried (turned in to coal)
• evident when they were burned by volcanoes and re-released massive amounts of 12C in to the atmosphere

Question 20

How would a sharp rise in atmospheric CO2 levels affect surface-ocean pH?

Answer 20

• lowers the pH of sea water (which is DIRE for marine organisms)