Plate Tectonics Flashcards Preview

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Flashcards in Plate Tectonics Deck (15)
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1
Q

Where does a constructive plate margin occur?

A
  • Where two plate margins are DIVERGING (moving apart)
2
Q

How are volcanoes and earthquakes produced from constructive plates?

A
  • The mantle is under pressure from the plates above it
  • The release of pressure eventually causes the mantle to melt, producing magma. The magma is LESS DENSE than the plate, causing it to rise above it
  • When the pressure becomes too much, the plates crack and buckle, causing a fault line and subsequently an earthquake
3
Q

Where do constructive plates form?

A

Where plates are diverging away from each other

4
Q

Where do destructive plates form?

A
  • Occurs when two plates are converging towards each other
5
Q

Where do conservative plates form?

A
  • Occurs when two plates are moving past each other
6
Q

How are earthquakes and volcanoes formed at constructive plate boundaries?

A
  • Mantle under pressure from plates above and when they move, pressure is released
  • Causes mantle to melt, producing magma and due to magma being less dense, it rises, forming a volcano
  • The plate may eventually buckle and crack due to pressure, forming a fault line
7
Q

How are ocean ridges created?

A
  • Diverging plates underwater form a ridge

- Underwater volcanoes erupt along the ridges, building above sea level

8
Q

How are rift valleys created?

A
  • Plates diverge beneath land, rising magma causes continental crust to fracture
  • Plates move and crust drops down forming a rift valley
9
Q

What happens at oceanic - continental plates?

A
  • Oceanic plate forced under the continental crust due to density
  • Fold mountains form from sediments of continental crust, folding upwards
  • Oceanic crust heats and melts into magma, rising to the surface, forming a volcano
  • The plates get stuck and once they get dislodged, causes an earthquake
10
Q

What happens on oceanic - oceanic plates?

A
  • Similar to oceanic - continental

- Volcanic eruptions that take place underwater form island arcs

11
Q

What happens at continental - continental plates?

A
  • Neither subduct, forming fold mountains and earthquakes
12
Q

Where do conservative plate boundaries form?

A
  • Occurs when two plates are moving past each other
13
Q

How do earthquakes occur at conservative plate boundaries?

A
  • Plates get locked in place, building pressure

- Pressure gets released as the plates jerk past each other releasing the energy as an earthquake

14
Q

What is a magma plume?

A

A vertical column of extra hot magma that rises from the mantle

14
Q

How to magma plumes form chains of volcanoes?

A
  • Magma plume reamins stationary, whilst crust moves above it
  • Volcanic activity in the part of the crust that was above the plume decreases as it moves away due to continental drift
  • A new volcano forms in the part over the plume
  • This eventually forms a chain volcanoes, e.g. Hawaii