lesson 1 - structure of the earth Flashcards Preview

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Flashcards in lesson 1 - structure of the earth Deck (8)
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1
Q

what is the top layer of the earth?

A

a dry brittle surface of recently cooled lava

2
Q

what are 3 points about the crust?

A

1) think rock layer at the surface
2) floats on the mantle
3) two types: oceanic and continental
4) continuously stressed (plate tectonics)

3
Q

what is the difference between oceanic and continental crust?

A

oceanic:

  • denser (heavier)
  • younger
  • mainly basalt

continental:

  • less dense (lighter)
  • older
  • mainly granite
4
Q

where is continental crust thickest?

A

under mountain ranges (20 - 60 km)

5
Q

what are 3 facts about the mantle?

A

1) accounts for 80% of the Earth’s volume
2) temp ranges from 5000 to 1300
3) two parts: upper lithosphere + asthenosphere

6
Q

what is the difference between the lithosphere and the asthenosphere?

A

lithosphere:

  • more rigid
  • cooler
  • closer to crust

asthenosphere:

  • semi molten
  • next to core
7
Q

what are the crust and mantle separated by?

A

moho discontinuity

8
Q

what are 3 facts about the core?

A

1) outer core = semi molten
2) inner core = solid
3) temperature at centre is 5,500