Week 3

Question 1

Which is the longest timescale, what is it driven by?

Answer 1

Tectonic scale, driven by earths internal heat, altering continental positions (earth’s geography)

Question 2

Name Theories for Earths Thermostat

Answer 2

• Carbon exchange

- Gaia Hypothesis

Question 3

What proof do we have that the earth was never Frozen.

Answer 3

• rock deposits(evidence of running water
• moving ice sheets
• primitive life forms

Question 4

Give information on Earths “Faint young sun”

Answer 4

The sun was 30% weaker 3.5 billion years ago, therefore how was the earth not a ball of ice, must be thermostat,

Question 5

What is the relationship between the size of the resovoir and the rate of carbon exchange?

Answer 5

Huge = slow
Small = fast
Inversely proportional

Question 6

List two types of CO2 output from rocks.

Answer 6

• Volcanic acitvity

- Chemical Weathering

Question 7

What is required for Hydrolysis to occur?

Answer 7

Rain, Atmospheric CO2, soil/silicate rocks.

Question 8

What is the difference between Hydrolysis and dissolution ?

Answer 8

• Dissolution no net CO2 is lost,

- in hydrolysis, silicates are used CaSiO3 , and in dissolution carbonates are used CaCO3.

Question 9

What factors affect Chemical weathering

Answer 9

• Temperature
• Precipitation
• Vegatations,

Question 10

Discuss chemical weathering as a thermostat. (Negative feedback)

Answer 10

As CO2 inputs increase, temperature, precipitation increases, vegetation, all of these things result in an increase in chemical weathering, thus reducing the CO2 concentration in a negative feedback loop

Question 11

What was the first form of life, how did it contribute to the earths climate?

Answer 11

Cyanobacteria, began photosythesis, pulling CO2 from the atmosphere.

Question 12

What are some of the first living creatures on earth Which had the first CaCO3 shell

Answer 12

Cyano bacteria, Red algae, Stromatolites, trilobites

Question 13

What are some critics vs supports of the Gaia hypothesis.

Answer 13

Critics, primitive organisms with CaCO3 shells could not have had a large enough impact to change atmospheric CO2 concentrations.
Supporters woul say the amount of life (photosynthesis/CaCO3) consumption was larger than expected.

Question 14

What is the keyword with respect to the worlds thermostat

Answer 14

Time-Scale.

Question 15

What are the two main layers of the tectonic plates? briefly describe the,

Answer 15

Lithosphere - Rock, hard, rigid.

Asthenosphere - Softer deeper layer that allows lithosphere to move

Question 16

What are the three types of plate margins?

Answer 16

• Divergent Margins
• Convergent Margins
• Transform Fault margins

Question 17

What is used to locate plates in the past?

Answer 17

Iron Rich basalts and their orientation relative to the poles.

Question 18

Can Geographic location of plates explain all weather patterns

Answer 18

No, although it does account for the geomorphic features we do observe today, it does not explain all weather. CO2 regulation is neccesary.

Question 19

Describe the BLAG hypothesis

Answer 19

A closed system, any imbalance results in climate change

1. CO2 is removed by CW
2. Buried in ocean
3. Subducted (plate movement)
4. Returned to ATM by volcanic activity

Question 20

Describe the Uplift Weathering Hypothesis

Answer 20

The more “Fresh” rock available for chemical weathering, the more chemical weathering that occurs, Caused by uplift (convergence)(more SA = more CW)

Question 21

What are interesting events that occurred during mid-cretaceous warmth (5)

Answer 21

• Dinosaurs
• large leafs
• no ice on earth
• high sea levels
• HOT

Question 22

Describe the Relationship of CO2 and temperature

Answer 22

Proportional, but not linear, at a certain point, the CO2 no longer increases temperature, maxing out.

Question 23

What is a large concern about a hot world (give value)

Answer 23

Drastically increasing sea level, 66 m! not to mention 7m of thermal expansion!