Lecture 5: Plate Tectonics and Climate Last 550 Myr (chapter 4) - PowerPoint PPT Presentation

About This Presentation
Title:

Lecture 5: Plate Tectonics and Climate Last 550 Myr (chapter 4)

Description:

Lecture 5: Plate Tectonics and Climate Last 550 Myr (chapter 4) Atmospheric CO2 Evolution Plate Tectonics Alfred Wegener (1914, German Meteorologist) proposed ... – PowerPoint PPT presentation

Number of Views:578
Avg rating:3.0/5.0
Slides: 29
Provided by: ccr63
Learn more at: https://aos.wisc.edu
Category:

less

Transcript and Presenter's Notes

Title: Lecture 5: Plate Tectonics and Climate Last 550 Myr (chapter 4)


1
Lecture 5 Plate Tectonics and ClimateLast
550 Myr (chapter 4)
2
Atmospheric CO2 Evolution
3
Plate Tectonics Alfred Wegener (1914, German
Meteorologist) proposed continental drift
1-10 cm/yr gt5000km/100myr
Soft? acts as viscous fluid allows the tectonic
plates above to move
4
Formation of the continents
  • Sea floor spreading
  • creation/destructoin of ocean crust
  • since 175 myr
  • Continental magnetic field
  • reconstruct continental positions (lat.)
  • since 550 myr

5
(No Transcript)
6
Paleomagnetic determination of past location of
continents the position of basalt rocks on (older
than 175 myr)
compass pointing vertical
compass pointing horizontal
7
Paleomagnetic dating of ocean crust
Magnetic reversal (over land) and magnetic
lineations (in ocean)
8
Moving Continents
Gondwana and S. P. Glaciation
100 Myr ago Cretaceous
Pangaea and Supermonsoon
200 Myr ago
9
The Polar Position Hypothesis for alternative
icehouse and greenhouse climate
Glaciation occurs near polar position, But polar
postion does NOT guarantee glaciation
What else?
10
Atmospheric CO2 Evolution
11
Tectonic Control of CO2 Removal
Uplift-Weathering Hypothesis Marueen
Raymo et al., 1980s
Uplifting gt create fresh rock and mineral
surfaces gtstronger weathering gt reduce CO2
12
The magic of breaking up
13
Quantifying weathering rate with time
100
1
  • Why fresh rocks has a much higher weathering rate
    (over 100 times)
  • Fresh rocks has more weathering materials
    fresh, unweathered silicates
  • Fragmentation increases surface area

14
Uplift and chemical weathering
15
Atmospheric CO2 Evolution
16
Tectonic control of CO2 BLAG spreading rate
hypothesis (Robert Berner, Antonio Lasaga, Robert
Garrels, 1983)
sea floor spreading gtvolcanic activitygtCO2
input
17
Age of sea floor
18
CO2 Change in the last 100 myr Hypothesis 1
BLAG hypothesis sea floor spreading gtvolcanic
activitygtCO2 increase
100 ma
now
19
Carbon cycle and stabilization of CO2
BLAG hypothesis sea floor spreading gtvolcanic
activitygtCO2 increase Further weathering
effect stabilizes CO2 and climate
20
Atmospheric CO2 Evolution and Tectonic control
of CO2 hypothesis
21
References for reading
Indonesian seaway, East Africa climate, and human
evolution Cane M. and P. Molnar, 2001 Closing
of Indonesian seaway as a precursor to east
African aridification around 3-4 million years
ago. Nature, 411, 157- 162
22
Supercontinent Pangaea and Supermonsoon
23
(No Transcript)
24
End of Chapter 5
25
(No Transcript)
26
(No Transcript)
27
(No Transcript)
28
Experiments in South America More weathering on
the slopes of Andes
Write a Comment
User Comments (0)
About PowerShow.com