Mass Extinctions

Question 1

9 possible causes of mass extinctions

Answer 1

Asteroid Impact
Flood Basalts
Sea level change
Global cooling/warming
Methane Clathrates
Anoxic events
Oceanic overturn
Gamma ray burst ozone
Plate tectonics

Question 2

What happens after an asteroid impact

Answer 2

Short term: rise in temperature

Long term: fall in temperature because debris fills atmosphere + blocks sun

Question 3

Flood Basalts

Answer 3

E.g. Deccan + Siberian Traps

Volcanic eruptions release large quantities of CO2

Question 4

Sea level change

Answer 4

Affect marine and terrestrial coastal life

Change coastal environment, can steel land

Question 5

Permo-Triassic extinction

Answer 5

251Ma
95% of all marine invertebrates killed
77% of tetrapods killed

Question 6

Causes of Permo-Triassic extinction

Answer 6

Plate tectonics - formation of Pangaea (evidence from stratigraphic record - fewer continental shelves, rapid climate change/fluctuation, change in oceans due to reduced input, widespread glaciation)
Volcanic activity - Siberian traps (largest volcanic eruption in history of earth) (effects: released poisonous gases which killed nearby plants + animals, ash particles caused global cooling which caused sea levels to fall due to increased glaciation, emitted CO2 + SO2 which caused global warming after the global cooling)
Methane Hydrates - melting of methane ice (melted due to heating because of the Siberian Traps, disrupt sea life + increase GHG in atmosphere caused further increase in temperature)

Question 7

Global cooling/warming

Answer 7

Warming = higher sea level (thermal expansion)
Cooling = lower sea level (locked up in ice caps)

Question 8

Methane Clathrates

Answer 8

Raise in temp causes methane clathrates + hydrates to melt

Powerful GHG causes further raise in temp

Question 9

Anoxic Events

Answer 9

Rise in sea level kills things

Things decay, use oxygen then no more oxygen

Question 10

Oceanic overturn

Answer 10

Change of ocean currents causes change in climate

Change in climate kills creatures that aren’t adapted to it

Question 11

Gamma ray burst-ozone

Answer 11

Gamma ray bursts damage the ozone layer

Destruction of ozone allows more radiation in which then harms us

Question 12

Plate Tectonics

Answer 12

Continental drift changes climates

Sea floor spreading cause larger MOR = higher sea level

Question 13

Ordivician-Silurian extinction event gggggg

Answer 13

Possible cause gamma ray bursts

Question 14

Cretaceous extinction ggggggg

Answer 14

Caused by