greenhouse and icehouse

Question 1

what is the cenozoic?

Answer 1

the greatest geologic era divided into periods

Question 2

what periods is the cenoxoic divided into?

Answer 2

paleogene, neogene, quaternary

Question 3

what are the periods of the cenozoic then divided into?

Answer 3

epochs

- paleocene and eocene

Question 4

what is Foraminifera?

Answer 4

pin head size single celled protozoa with a shell made of CaCO3

Question 5

what is the ratio of oxygen isotope in their shells sensitive to?

Answer 5

temp and ice vol

Question 6

when was the paleocene?

Answer 6

65-55Ma

Question 7

when was the Eocene?

Answer 7

53-34 Ma

Question 8

what indicates rapid acidification of the ocean?

Answer 8

dissolution of carbonate sediments

Question 9

what is the volcanic trigger hyp?

Answer 9

• a large flood basalt intrusion from Iceland began to open the N Atlantic 56.1 Ma with the splitting of continents 55 Ma
• 5-10 mil km^3 of basalts deposited in 1 myr intruded into fossil-fuel rich sediments
• this released CO2 and the thermogenic methane
• thermogenic methane is less 13C depleted than biogenic methane hence more of it would be required to explain the 13C excursion

Question 10

what are methane hydrates?

Answer 10

• gas molecules trapped inside a frozen water lattice

Question 11

where do methane hydrates form?

Answer 11

in the pore spaces in sediments and occur in a layer of ocean sediments stabilise day high pressure and cold temps

Question 12

how can methane hydrates be stabilised?

Answer 12

• increasing temp of overlying water
• depressurisation by lowering sl
• slope failure

Question 13

how long does it take for the ocean to be replenished with alkalinity from silicate weathering?

Answer 13

> 100 kyr

Question 14

hyp for the Paleocene-Eocene Thermal Maximum

Answer 14

• warming of intermediate depth ocean waters destabilised methane hydrate
• outgassing of methane added to warming causing more methane to be released
  +ve feedback

Question 15

what is the total of CH4 released during PETM?

Answer 15

1500 GtC

Question 16

what can you learn from the PETM?

Answer 16

• the amount of C released at the PETM is comparable to known fuel reserves today and gave at least 5C long-term warming
• it will take at least 100 Ayr for the carbon cycle and climate to recover

Question 17

when was the interval of extreme warmth?

Answer 17

55 Ma

Question 18

who stated the Himalayan uplift hyp?

Answer 18

Raymo and Ruddiman (1992)

Question 19

what was the Himalayan uplift hyp?

Answer 19

• uplift of the Himalayas caused increased weathering rates
• this decreased atmospheric CO2 thus cooling the planet
• should have caused a -ve feedback response
• lower CO2 and temp reduce silicate weathering until it again matches degassing

Question 20

problems with the Himalayan hyp

Answer 20

• global erosion has been constant for at least the past 10 mar, despite mountain building

Question 21

when was the miocene?

Answer 21

23-5.3 Ma

Question 22

what stabilised the miocene?

Answer 22

• at 200-250 ppm, CO2 during the miocene upland veg was near CO2 starvation
• this limited the effect go plants on weathering, holding CO2 stable

Question 23

what are the 3 stages of grassland spread?

Answer 23

• eocene 33 Ma desert grasslands
• early miocene 17 Ma ungulates, horse
• late miocene 7 Ma C4 grasses

Question 24

when was the Pliocene?

Answer 24

5.3-2.58 Ma

Question 25

when was hominia?

Answer 25

6 Ma

Question 26

where is the origin of hominia?

Answer 26

great Rift Valley