Types Of Plate Boundries - Key Words And CS

Question 1

What are the types of landforms in constructive divergent plate boundaries?

Answer 1

Mid Atlantic Ridge
African rift valley

Question 2

Mid Atlantic ridge: tectonic, geological location, characteristics (7)

Answer 2

. Divergent constrictive plate boundary
. Continental plate
. South west coast of Iceland ( erupted from a submarine volcano in 1965)
. North American plate ( moving west ) and Eurasian plate ( moving east )
. Basaltic lavas, gentle, low viscosity, low magnitude and high frequency
. Columnar jointing- forms when basalt lavas cool down slowly in the crust
. Rifting+ crystal thickening

Question 3

East African Rift Valley: tectonic, geological location, characteristics (6)

Answer 3

. Divergent constructive plate boundary
. Oceanic
. A triple junction between the Nubian, Somalian and Arabian plate
. Drip slip faults: associated with crystal thinning and caused seismic activity ( gravity pulls the continental crust and slides down the asthenosphere )
. Low frequency eruptions
. Kilimanjaro ( east rift) associated with crystal thinning- Dormant volcano

Question 4

What are the types of landforms in Destructive convergent plate boundaries?

Answer 4

Ocean trench
Fold mountains

Question 5

Chile/ Peru trench (Andes): tectonic, geological location, characteristics (7)

Answer 5

. Convergent destructive plate boundary
. Continental/oceanic ( fold mountains)
. Nazca plate ( oceanic) and South American plate ( continental )
. The Andean Batholith ( very large igneous intrusion)
. Slab pull ( aids subduction)
. Accretionary prism ( accumulation of sediment in trenches )
. Diapers: domes of hot spring magmas that intrude into the continental plate
. Seismic activity: high frequency and high magnitude, high viscosity( very rapid ,explosive and effusive )

Question 6

Mariana Ocean Trench: tectonic, geological location, characteristics (6)

Answer 6

. Destructive convergent plate boundary
. Oceanic/ Oceanic
. The Philippine plate ( oceanic ) and Pacific plate ( oceanic)
. Accretionary prisms ( accumulation of sediment in ocean trenches)
. Marina Islands ( volcanic island arc)
. The melting of subducting crust in the Benioff zone produce rising magmas creating seismic activity- this creates volcanic Island arcs

Question 7

Himalayan mountains: tectonic, geological location, characteristics (8)

Answer 7

. Convergent destructive plate boundary
. Young fold mountains
. Indian collides with the Eurasian plate
. continental/ continental
. Shallow seismic activity
. Zone of crystal compression and thickening
. Crust is very thick, so magma will struggle to reach the surface- therefore no volcanic activity
. Diapers

Question 8

What are the types of Landforms in conservative plate boundaries?

Answer 8

Transform/ strike slip faults

Question 9

San Andreas fault: tectonic, geological location, characteristics (5)

Answer 9

. Conservative/ lateral
. Pacific plate and North American plate
. Seismic activity
. Actual plate movement: moving in the same direction at different speeds
. V shape valleys

Question 10

Hawaiian hotspot: tectonic, geological location, characteristics (5)

Answer 10

. In the interior of the Pacific Ocean
. Archipelago ( group of Islands )
. It gets older as it is further away from the hotspot ( it becomes dormant, extinct and then seamounts )- this can indicate the direction of plate movement
. Shield volcanoes, Mauna loa- low viscosity, high frequency, low magnitude shallow flanks

Question 11

Continental and oceanic ( destructive plate boundary)

Answer 11

. Denser oceanic plate subducts below the continental plate
. The plate subducting leaves a deep ocean trench
. Fold mountains occur when sediment is pushed upwards during subduction
. Pressurised magma forces through weak areas in continental plate which forms explosive, high pressure volcanoes ( composite volcanoes)

Question 12

Oceanic and oceanic ( destructive plate boundary)

Answer 12

. Heavier plate subducts leaving an ocean trench. Fold mountains will also occur
. Build up of pressure causes underwater volcanoes
. Lava cools creating new land called Island arcs

Question 13

Continental and continental ( destructive plate boundary)

Answer 13

. Both plates not as dense so pressure builds up
. Pile up of continental crust on top of the lithosphere due to pressure between plates
. Fold mountains are formed

Question 14

Oceanic and oceanic ( constructive plate boundary)

Answer 14

. Magma rises in between the gap and new land forms when cooled- known as sea floor spreading

Question 15

Continental and continental ( constructive plate boundary)

Answer 15

. Any land in the middle of the separation is forced apart, causing a Rift Valley!
. The gap will be filled with water and separate completely from the main island.
. Lifted areas of the rock are know as horsts and valley itself is known as graben

Question 16

Slab pull

Answer 16

The gravitational pull effect of the subducting plate pulls the adjoining plate downwards

Question 17

Ridge push

Answer 17

The slope created when plates move apart due to gravitational effect. Gravity pushes plates further away, widening the gap

Question 18

Hotspots

Answer 18

. Hotspots are not related to plate boundary.
. Hot magma plumes from the mantle rises and burns through weaker parts of the crust which can create volcanoes and islands.
. The plume stays the same but the plates continue to move which can sometimes cause chain of islands ( archipelago )

Question 19

Continental crust

Answer 19

Thickness- thick (30-70km)
Density- less dense
Composition-acidic, granite, sial
Age- thousands of millions older (1.5- 2billion years )

Question 20

Oceanic crust

Answer 20

Thickness- thinner (6-10km)
Density- denser
Composition- basaltic, basic, sima
Age- younger ( 40 to 70 million years)- this is because when subduction occurs, crust is always recycled