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Flashcards in C1 Earth Deck (13)
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1

Label the Earth

2

What are the broken sections of the Earth’s crsut and upper mantle that move called?

Tectonic plates

3

What type of currents allow these sections of crust and upper mantle to move?

Convection

4

How are the currents that move the plates made?

Radioactive processes in the core

5

At what speed do the plates move?

Few centimetres a year

6

Where do earthquakes and volcanoes occur?

At the edges of the plates or plate boundaries

7

Why do earthquakes occur?

Movement of plates causes stresses and strain to build up between the plates, then they suddenly move.

8

Why can scientists not accurately predict earthquakes or volcanoes?

Can’t see under the crust

9

Describe the early ideas about how the mountains were formed.

Earth cooled and contracted, shrinking and causing wrinkling on the surface

10

Give 3 pieces of evidence that Wegener had observed that supported his ideas of continental drift.

On opposite sides of the Atlantic:

Similar ancient rocks

Very similar fossils

Shapes fitted on the coastline

11

What is continental drift?

All the continents were once a supercontinent and it broke up and the continents had slowly moved apart

12

Give 3 reasons why did the other scientists not accept his ideas at the time?

No evidence of how the continents moved

Other explanations eg land bridge

He was not a geologist

13

Why do scientists now accept his ideas?

New evidence on the ocean floor explained how the crust can move – plate tectonics