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Earth 002
Thursday, January 21st, 1999
Announcements: TA's Office Hours: T
12:45-1:45, W 10:00-11:00; 312 Deike
Lecture notes:
DAISYWORLD HOMEWORK REVIEW
THE EARTH'S COMPONENTS
- Geosphere-rocks (also known as lithosphere)
- Atmosphere-air
- Hydrosphere-oceans
- Cryosphere-icy components
- Biosphere
ENERGY IN OUR ATMOSPHERE
- Energy is put into our atmosphere it two different ways
- One is through solar energy-energy from the sun
- Another method is from Earth's interior-meaning
the radioactive decay of Thorium (T) and Uranium (U)
ROCK CYCLE
- This is what controls the components of the atmosphere
HYSOGRAPHIC CURVE
- This curve depicts the elevations of Earth's continents
and oceans
- Earth maintains mostly continent and ocean (about 30%
continent, 70% ocean)
- There are very small areas on earth that are very high
or very low
ALFRED WEGENER
- Wegener beleived that all land on earth was orginally
joined together as one huge continent, supporting this
hypothesis with 5 pieces of evidence
- Jigsaw Puzzle-the shapes of the continents look as
though they were once together and have drifted apart
- Rocks Matched-rocks on the coastline of each
"puzzle piece" matched and were over 100
billion years old
- Fossils-similar fossils found on the coastlines
- Ice-scientists mapped the flow of the ice and the
direction of glacier flow, realizing the only way it
could have worked would be if the continents were all
connected once
- Paleo Magnetism-new evidence
GEOCENTRIC DIPOLE
- The geocentric dipole is a magnetic pole centered on the
Earth's axis
- The magnetism of rocks is created when the rock is
originally formed
MAGNETIC ANOMALIES
- Suggests that South America and Africa were originally
together, then after being pulled apart new material was
created
- The ripping apart of continents reveals new molten rock
that causes the Earth's magnetic fields to freeze thus
creating new sea floor
- The Earth's magnetic field has flip-flopped 36
times in 76 million years
PLATE TECTONICS
- Rigid-rigid plates are found all over the Earth
- Creation-the creation of new crust occurs because
the old crust is being ripped apart
- Destruction-deep sea trenches are being destroyed
- Translation-this is where ridges/plates slide past
each other, creating transformed faults
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