13. 3- Internal forces of relief
Continental drift theory
Continental drift was a theory proposed in 1912 by Alfred
Wegener which postulated the movement of continents. This
theory is a part of the concept of plate tectonics. Continents
have been drifting for hundreds of millions of years.
Nowadays there exists lots of evidence for continental drift.
The most obvious is the way in which the continents seem to fit
jigsaw-like (for example Africa and South America) together
when looked at on a map. More scientific evidence comes in
the form of plant and animal fossils of the same age found
around different continent shores, suggesting that they were
once joined.
14. Pangaea
Pangaea (/pæn d iˈ ʒ ːə/)
was a supercontinent
that existed during the
late Paleozoic and
early Mesozoic eras,
forming about 300
million years ago. It
began to break apart
around 200 million
years ago. The single
global ocean which
surrounded Pangaea is
accordingly named
Panthalassa.
15.
16. Tectonic plates
A theory that explains the global distribution of geological phenomena
such as seismicity, volcanism, continental drift, and mountain building
in terms of the formation, destruction, movement, and interaction of
the earth's lithospheric plates.
27. Activities
Exercise 1 on page 28.
Exercises 2, 3 and 4 on page 29.
And finally, investigate! Exercise 5 on page 29,
and 11 on page 33.
28. 4- How does relief change?
CHANGES IN RELIEF
Relief is also shaped by external forces: temperature, water,
wind and human action. There are 3 processes:
EROSION: the wearing away of rocks and other deposits on the
earth's surface by the action of water, ice, wind, etc.
TRANSPORTATION: the eroded material is transported by water
or wind.
DEPOSITION: the material is deposited in areas where
sediments accumulate.
43. Topographic profile
A topographic profile is a cross sectional view along a line
drawn through a portion of a topographic map. In other
words, if you could slice through a portion of the earth, pull
away one portion, and look at it from the side, the surface
would be a topographic profile.