Geography tectonic Kq 1

Question 1

oceanic crust vs continental crust

Answer 1

Oceanic crust
-under deep ocean
-young rock less that 200 mill
-thinner (5-8km)
Made of basalt (thick and dense)
Subducts under less dense crust

Continental (under earths continental crust, wide age range (4billion),thicker(35-70km),made of granite, no subduction but brittle and breaks,buckles,folds

Question 2

why tectonic plates move

Answer 2

1)Magma near core heater expands and rises
2)rises and move sideways dragging plates away from each other (divergent plate boundary)
3) magma cooled and go down dragging plate towards each other (convergent plate boundary)
4)slab-pull force when denser subducted plate pulls rest of the plate-down moving pattern cause convection currents
5)Magma near core get heated and process repeats

Question 3

distribution of plate boundaries

Answer 3

North American plate. South American,african,eurasian.indian,pacific platex2,australian,antartic plate

Question 4

divergent
oceanic-oceanic

Answer 4

2 oceanic plates move away from each other cracks form at boundary.
Rising magma fills the gap between the plates,- creates new seafloor as magma cools and solidifies(process known as seafloor spreading)
* Magma rises at the zone of divergence to create a new ridge called
a MID-OCEANIC RIDGE. E.g. Mid-Atlantic Ridge

Question 5

divergent continenetal continental

Answer 5

When two continental plates diverge,
* brittle crust breaks and fractures, forming fault lines at the plate boundary.
* The opposing tensional forces cause the land in between the two continental crusts to sink
* The resultant landform is a linear depression known as a RIFT VALLEY.
* Taller blocks of land on either side known as BLOCK MOUNTAINS.
* A number of active volcanoes and earthquake fractures can also
be found along the East African Rift Valley.

Question 6

convergent oceanic-oceanic

Answer 6

When 2 oceanic plates move towards each other,
* the denser oceanic plate will be pushed beneath the less dense
oceanic/ continental plate. Subduction occurs.
* As a result, a linear depression on the sea floor known as OCEANIC
TRENCH is formed.

Question 7

convergent oceanic-continental

Answer 7

At/Along oceanic plates:
* As the plate sinks into the mantle, it melts and form magma.
* The magma rises through the crust to form VOLCANOES.
* Over time, a(n) chain/ arc of VOLCANIC ISLANDS may be created.
At/Along continental plates:
* The continental crust buckles and folds due to pressure from the subducting oceanic crust underneath it, creating FOLD MOUNTAINS.
* Earthquakes may occur due to friction caused by the moving plates.

Question 8

continental-continental

Answer 8

When 2 continental plates move towards each other,
* the crusts are compressed/ pushed together,
* and the compressional force causes the crust to buckle and fold
upwards or sideways.
* Over time, the folding of the crusts forms a range of FOLD
MOUNTAINS.
* Earthquakes are common due to the stress generated from the
colliding continental plates.

Question 9

transform

Answer 9

At transform plate boundaries, plates slide past each other, neither
creating nor destroying the crust.
* In the process of the uneven movement, tremendous stress builds up
at the boundaries.
* The eventual release of the stress results in violent earthquakes.
* The earthquakes may result in further plate movement and ground
faulting, but there is generally little/ no volcanic activity. E.g. North
Anatolian Fault - an earthquake almost every 10 years in the last 70 years