2.
On the following slide, pick 3 statements that apply to the core, 3 applying to the mantle and 3 applying to the crust.
Approximately the size of Mars.
The most dense part of the planet.
Made up of rocks rich in iron and nickel.
Temperature over 6000˚C.Surrounded by semi-molten outer core.
The inner core is solid.
Starts about 2900km down.
Centre is 6350km down.
Separated from the core by the Gutenburg discontinuity.
Largely composed of silicate rocks rich in iron and magnesium.
Upper mantle (close to the crust) is rigid and together with the crust forms the LITHOSPHERE.
Most of the mantle (asthenosphere) acts like it is semi-molten.
Temperatures near the core reach 5000˚C.
High temperatures near the core are believed to be responsible for the generation of convection currents. Thinnest, coolest and least dense layer.
Rocks are rich in silicon, oxygen, aluminium, potassium and sodium
Separated from the mantle by the Mohorovijic (Moho) discontinuity.
Varies in thickness from 5 to 70 km.
8.
....... million years ago all the continents were joined together to form one “supercontinent” called .............
Fill in the blanks!
10.
Give an example for each of the following types of evidence supporting plate tectonics theory:
Geological evidenceClimatological evidenceBiological evidence
13.
• Where plates move apart in oceanic areas they produce.....-.............. ....................
• Where they move apart in continental crust areas they produce ........... ................. .
18.
Think of a location where two continental plates have collided.
Name the two plates involved and any feature that were created as a result of the collision.
A = Crust
B = Mantle C = Outer core
D = Inner core
Write the correct terms forA, B, C, D
(4 marks)
1.
2.
On the following slide, pick 3 statements that apply to the core, 3 applying to the mantle and 3 applying to the crust.
Approximately the size of Mars.
The most dense part of the planet.
Made up of rocks rich in iron and nickel.
Temperature over 6000˚C.Surrounded by semi-molten outer core.
The inner core is solid.
Starts about 2900km down.
Centre is 6350km down.
Separated from the core by the Gutenburg discontinuity.
Largely composed of silicate rocks rich in iron and magnesium.
Upper mantle (close to the crust) is rigid and together with the crust forms the LITHOSPHERE.
Most of the mantle (asthenosphere) acts like it is semi-molten.
Temperatures near the core reach 5000˚C.
High temperatures near the core are believed to be responsible for the generation of convection currents. Thinnest, coolest and least dense layer.
Rocks are rich in silicon, oxygen, aluminium, potassium and sodium
Separated from the mantle by the Mohorovijic (Moho) discontinuity.
Varies in thickness from 5 to 70 km.
The Core• Approximately the size of Mars• Starts about 2900km down• Centre is 6350 km down• The most dense part of the planet• Made up of rocks rich in iron and nickel• Core temperature over 6000oC• Outer core is semi-molten/liquid (only part of the planet which is!)• Inner core is solidThe Mantle• Separated from the core by the Gutenburg discontinuity• Largely composed of silicate rocks rich in iron and magnesium• Upper mantle (close to the crust) is rigid and together with the crust forms the lithosphere• Most of the mantle (asthenosphere) acts like it is semi-motlen.• Temperatures near the core reach 5000oC• High temperatures near the core are believed to be responsible for the generation of convection
currents.The Crust• Thinnest, coolest and least dense layer.• Rocks are rich in silicon, oxygen, aluminium, potassium and sodium• Separated from the mantle by the Mohorovijic (Moho) discontinuity.• Varies in thickness from 5 to 70 km
3 x 39 marks
3.What is the difference between the lithosphere
and the asthenosphere? (1 mark)
• Lithosphere: consists of the crust and the rigid upper section of the mantle, approximately 80-90km thick. Divided into seven large plates and a number of smaller ones.
• Asthenosphere: the semi-molten mass below the lithosphere on which the plates float and move. Beneath the asthenosphere is the rest of the mantle, which is completely solid.
4.
Which is thicker?Continental crust or oceanic crust?
Continental (30-70km)Oceanic (6-10km)
(1 mark)
5.
Which is older?Continental crust or oceanic crust?
Continental (over 1,500 million years)Oceanic (less than 200 million years)
(1 mark)
6.
Which is more dense?Continental crust or oceanic crust?
Oceanic (heavier)Continental (lighter)
(1 mark)
7.
What do SIMA and SIAL stand for?Which type of crust does each abbreviation
apply to?
SIMA = silicon, magnesium, oxygen (oceanic)SIAL = silicon, aluminium, oxygen (continental)
(3 marks)
8.
....... million years ago all the continents were joined together to form one “supercontinent” called .............
Fill in the blanks!
8.
250 million years ago all the continents were joined together to form one “supercontinent” called Pangaea
(2 marks)
9.
In modern times, why might it be difficult to make the shapes of the continents back together?
• There are differences in modern and ancient coastal morphologies.
• Variations in sea level.( 2 marks)
10.
Give an example for each of the following types of evidence supporting plate tectonics theory:
Geological evidence Climatological evidenceBiological evidence
(3 marks)
Geological evidence
• The Appalachian Mountains of eastern North America are thought to link to the Caledonides of Ireland, Britain, Greenland, and Scandinavia and the Anti-Atlas Range in Morroco.
Climatological evidence
• Coal deposits that would have been formed in tropical climate conditions are found in places that do not have a tropical climate. Therefore, they must have drifted. E.g. Antarctica
Biological evidence
• Mesosaurus remains were found in southern Africa and eastern South America, two far away places. Mesosaurus was a freshwater animal, and could not have crossed the Atlantic Ocean, this indicates that the two continents used to be joined together.
• Marsupials are only found in Australia because it drifted away from the main supercontinent before the predators that wiped them out elsewhere had migrated there
12.
Name the three main types of plate boundary:• CONSTRUCTIVE /Divergent boundaries -- where new crust is
generated as the plates pull away from each other.
• DESTRUCTIVE /Convergent boundaries -- where crust is destroyed as one plate moves under another.
• CONSERVATIVE /Transform boundaries -- where crust is neither produced nor destroyed as the plates slide
horizontally past each other.
(3 marks)
13.
• Where plates move apart in oceanic areas they produce.....-.............. ....................
• Where they move apart in continental crust areas they produce ........... ................. .
• Mid-oceanic ridges• Rift valleys(2 marks)
14.
• Name the oceanic ridge on which the country Iceland has been formed.
• Mid-Atlantic Ridge!
(1 mark)
15.What is the geographical term for the features the arrows are pointing to?
Transform faults!
(1 mark)
16.
Name 3 features that are commonly created during Oceanic-continental convergence.
- Deep ocean trenches- Fold mountains- Volcanic arcs (volcanoes)(3 marks)
Benioff zone – the further the rock descends, the hotter the surroundings become. This, together with the heat generated from friction, begins to melt oceanic plate into the magma.
Rocks scraped off the descending plate and folding of the continental crust create young fold mountain chains on edge of the continental mass. E.g the Andes.
Deep ocean trenches are found along the seaward edge of destructive margins. They mark where one plate begins to descend beneath another and can reach great depths. E.g. Peru-Chile trench, 8km deep
As it is less dense than the surrounding asthenosphere, the molten material begins to rise up through fissures and by burning their way through overlying rock. Eventually these reach the surface to form volcanoes.
The lava has a viscous nature (flows less easily). This creates complex , composite, explosive volcanoes. If the eruptions take place off shore, a line of volcanic islands
known as an island arc can appear
17.
Name the two main features associated with Oceanic - oceanic convergence.
- Ocean trenches- Volcanic islands arcs(2 marks)
18.
Think of a location where two continental plates have collided.
Name the two plates involved and any features that were created as a result of the collision.
(3 marks)
Indo-Australian PlateMoving north and east
Eurasian Plate (rigid)
Himalayas
Approx. 5.8cm/year
In parts the Indo-Australian plate is being pushed under to form the mountain roots up to 70km deep. This movement causes great stresses which are released by earthquakes.Often extremely violent and destructive. E.g. Sichuan, 2008 – China, 80,000 deaths.
Causing Mt Everest to rise by up to 3cm a year.
19.
Give an example of a conservative plate margin. List 2 facts about it:
- San Andreas Fault- Pacific plate moving north-westwards at
6cm/year.- The North American plate moves north-
westwards by 1cm/year(3 marks)
The San Andreas Fault.• California• Although both plates are moving north-west, the Pacific plate
moves faster, giving the illusion that they are moving in opposite directions.
• Los Angeles could eventually be on an island off the Canadian coast.