Plate tectonics

When did the Earth form?

4.6 billion years ago
When did the early atmosphere form?

4-3.8 billion years ago
Early Earth:
- Earth cooling – continents forming condensing water forms oceans
- volcanic outgassing
- Water vapor
- Ammonia (NH3)
- Methane (CH4)
- Hydrogen sulfide (H2S)
- Hydrogen gas (H2)
- Carbon dioxide (CO2)
- formation of Earth’s magnetic field
Photosynthesis:
- CO₂ + H₂O + sun ---> C₆H₁₂O₆ + O₂
- 2.3 billion years ago
- blue algae could make its own food
aerobic resperation
- O₂ + CHO --> CO₂ + H₂O
- (single-celled bacteria)
development of the ozone
- 1 billion years ago
- filters harmful UV radiation
- crucial for the ability to colonize on land
Cambrian
- 530 million years ago:
- multi-celled organisms
- life is widespread in the oceans
Devonian
- 450 Million years ago
- terrestrial organisms all over
- modern atmosphere
Theory of plate tectonics:
- lithosphere broken into a
- number of rigid plates (at least 13 major) “floating” in the asthenosphere
- plates move slowly (~2 cm/year)
- movement causes plates to collide ® Plate boundary
Seafloor spreading

age of oceanic crust increases outward from ridges
Cambrian (picture)

Author

kamrunsreno

12321

Card Set

Plate tectonics

Description

NRES 211 midterm

Updated

2010-03-29T05:30:29Z

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