Week 3 Flashcards
Which is the longest timescale, what is it driven by?
Tectonic scale, driven by earths internal heat, altering continental positions (earth’s geography)
Name Theories for Earths Thermostat
- Carbon exchange
- Gaia Hypothesis
What proof do we have that the earth was never Frozen.
- rock deposits(evidence of running water
- moving ice sheets
- primitive life forms
Give information on Earths “Faint young sun”
The sun was 30% weaker 3.5 billion years ago, therefore how was the earth not a ball of ice, must be thermostat,
What is the relationship between the size of the resovoir and the rate of carbon exchange?
Huge = slow
Small = fast
Inversely proportional
List two types of CO2 output from rocks.
- Volcanic acitvity
- Chemical Weathering
What is required for Hydrolysis to occur?
Rain, Atmospheric CO2, soil/silicate rocks.
What is the difference between Hydrolysis and dissolution ?
- Dissolution no net CO2 is lost,
- in hydrolysis, silicates are used CaSiO3 , and in dissolution carbonates are used CaCO3.
What factors affect Chemical weathering
- Temperature
- Precipitation
- Vegatations,
Discuss chemical weathering as a thermostat. (Negative feedback)
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
What was the first form of life, how did it contribute to the earths climate?
Cyanobacteria, began photosythesis, pulling CO2 from the atmosphere.
What are some of the first living creatures on earth Which had the first CaCO3 shell
Cyano bacteria, Red algae, Stromatolites, trilobites
What are some critics vs supports of the Gaia hypothesis.
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.
What is the keyword with respect to the worlds thermostat
Time-Scale.
What are the two main layers of the tectonic plates? briefly describe the,
Lithosphere - Rock, hard, rigid.
Asthenosphere - Softer deeper layer that allows lithosphere to move
What are the three types of plate margins?
- Divergent Margins
- Convergent Margins
- Transform Fault margins
What is used to locate plates in the past?
Iron Rich basalts and their orientation relative to the poles.
Can Geographic location of plates explain all weather patterns
No, although it does account for the geomorphic features we do observe today, it does not explain all weather. CO2 regulation is neccesary.
Describe the BLAG hypothesis
A closed system, any imbalance results in climate change
- CO2 is removed by CW
- Buried in ocean
- Subducted (plate movement)
- Returned to ATM by volcanic activity
Describe the Uplift Weathering Hypothesis
The more “Fresh” rock available for chemical weathering, the more chemical weathering that occurs, Caused by uplift (convergence)(more SA = more CW)
What are interesting events that occurred during mid-cretaceous warmth (5)
- Dinosaurs
- large leafs
- no ice on earth
- high sea levels
- HOT
Describe the Relationship of CO2 and temperature
Proportional, but not linear, at a certain point, the CO2 no longer increases temperature, maxing out.
What is a large concern about a hot world (give value)
Drastically increasing sea level, 66 m! not to mention 7m of thermal expansion!
