Unit 121 These observations lead him to come up with the A very long time ago 200 million years the continents were joined together in a called ID: 639386
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Slide1
Evidence for Continental Drift
Unit 12.1Slide2Slide3
These observations lead him to come up with the ___________________________
A very long time ago (~200 million years) the continents were joined together in a
___________________
called ______________.Continents _________ around the world
continental drift theory
supercontinent
Pangaea
moveSlide4
1. The shape of the continents
The shape of the continents fit together like jigsaw pieces.
the continents fit together even better if we include the
___________________________
continental shelfSlide5
1. The shape of the continentsSlide6
1. The shape of the continentsSlide7
PangaeaSlide8
2. Matching geological featuresSlide9
3. Matching fossilsSlide10
3. Matching fossilsSlide11
4. PaleoglaciationSlide12
4. PaleoglaciationSlide13
4. PaleoglaciationSlide14
Some scientists opposed Wegner’s theory of continental drift
The age of the Earth is debated. Continental drift takes a VERY long time and many scientists believe ___________________________
Wegener could not explain
how continental drift occurs. How can huge pieces of land move?
that the Earth is too youngSlide15
The Earth
Unit 12.2Slide16Slide17Slide18Slide19
Tectonic plates are like giant pieces of rock ____________ on top of the ___________ asthenosphere. They float on
magma
there are ______ major tectonic plates and many smaller onescontinents are _________ to the tectonic platestectonic plates are always ______________Slide20
Tectonic plates are like giant pieces of rock ____________ on top of the ___________ asthenosphere. They float on
magma
there are ______ major tectonic plates and many smaller onescontinents are _________ to the tectonic platestectonic plates are always ______________
floating
moltenSlide21
Tectonic plates are like giant pieces of rock ____________ on top of the ___________ asthenosphere. They float on
magma
there are ______ major tectonic plates and many smaller onescontinents are _________ to the tectonic platestectonic plates are always ______________
floating
molten
12
attached
movingSlide22Slide23
Why do the tectonic plates move?Slide24Slide25
Convection
is a process where hot material _________ and cool material _________.
Tectonic plates are always moving due to
convection. They move at a rate of ______________!
rises
sinks
2 cm/year