EQ1:Distribution And Boundaries

Question 1

What 4 parts is the earth made up of?

Answer 1

-The Crust
-The mantle
-The outer core
-The inner core

Question 2

What is the lithosphere?

Answer 2

The lithosphere is the solid, outer part of Earth, including the brittle upper portion of the mantle and the crust.

Question 3

What are the features of the lithosphere?

Answer 3

Temperature:Up to 400°C.
Composition:Oceanic crust (dense, 3.3g/cm³, basalt) and continental crust (less dense, 2.7g/cm³, granite)
Physical State:Solid
Thickness:Oceanic crust: 6–10 km
Continental crust: up to 70 km.

Question 4

What is the asthenosphere?

Answer 4

A zone of Earth’s mantle lying beneath the lithosphere and believed to be much hotter and more fluid than the lithosphere

Question 5

What are the features of the mantle?

Answer 5

-is about 870•C
-medium density(3.3-5.4g/cm)
-the upper part is solid (part of the lithosphere)
-the lower part is semi-molten (part of the asthenosphere)
-700km deep- 2890km deep

Question 6

What are the features of the outer core?

Answer 6

-4400 to 6100•C
-dense (9.9 to 12.3G/cm)
-it is 12% sulphur and 88% iron
-it is made up of liquid iron and nickel

Question 7

What are the features of the inner core?

Answer 7

-it has a temperature of 7000•C (radioactive decay)
-very dense at around 13.5g:cm
-20% nickel and 80% iron

Question 8

What are the 4 theories that explain why tectonic plates move?

Answer 8

1)Mantle Convection
2)Sea Floor Spreading
3)Subduction Zone movement- destroyed crust
4)Slab pull

Question 9

What is mantle convention?

Answer 9

•In the past, the theory of convection currents was used on its own to explain tectonic plate movement
•The heat from radioactive decay in the core moves upwards into the mantle
•It creates convection currents which push up into the spreading mid-ocean ridges, forcing them further apart called the ridge push

Question 10

What is Sea Floor Spreading?

Answer 10

-a process where new oceanic crust is formed at mid ocean ridges as tectonic plates move apart at divergent boundaries
-magma rises from beneath the earth’s surface, cool and solidifies pushig older crust away from the ridge and creating a continuous renewal of the oceanfloor

Question 11

What is subduction and slab pull?

Answer 11

*A subduction zone (benioff zone) is formed when two plates meet- The heavier, denser plate subducts under the lighter, less dense plate leadng to the formation of deep ocean trenches
*As it sinks, it drags or pulls the rest of the plate with it. This pulling motion drives the movement of tectonic plates (slab pull)

Question 12

Where are Earth’s major plates?

Answer 12

Question 13

What are divergent plate boundaries (constructive)?

Answer 13

Plates that move apart from each other most commonly found at mid ocean ridges

Question 14

What processes occur at divergent plate boundaries?

Answer 14

Earthquakes:
-Large numbers of shallow focus and generally low magnitude earthquakes with most earthquakes being submarine (under the sea and therefore low risk to humans)
-they create spreading ridges in the ocean and do not typically trigger tsunamis

Volcanoes:
-new oceanic crust is created leading to the creation of rift volcanoes in a mid ocean ridge
-shield less explosive volcanoes are created- the lava is basaltic with low viscosity

Question 15

What are conservative plate boundaries?

Answer 15

•There are where one plate slides against another at a different speed creating friction
•The movement is horizontal to the left or to the right
•consists of transform faults (weaknesses in crust) which join up in a zig zag pattern (locked faults) e.g. The San Andreas Fault where the North American and Pacific plates both move north at different speeds creating friction

Question 16

What processes occur at conservative plate boundaries?

Answer 16

Earthquakes:
-Extensive shallow focus earthquakes, occasionally of considerable magnitude
-Zones of friction are created as plates slide past one another so this plate type presents more risk to humans

Volcanoes:
-there is no volcanic activity because lithosphere is neither created or subducted

Question 17

What are convergent plate boundaries (destructive)?

Answer 17

oceanic-continental:
•plates move towards each other and the more dense oceanic plate slides below
•where this occurs is called the subduction zone (or Benioff zone) and is where huge friction is generated by 2 plates and deep ocean trenches appear

oceanic-oceanic:
•when two oceanic plates converge the oceanic crust that is denser sub-ducts the other creati by a trench

Question 18

What processes occur at convergent (destructive) plate boundaries ?

Answer 18

Earthquakes:
- Generates some of the largest and most damaging earthquakes.
- Can also trigger devastating tsunamis.
- High magnitude but less frequent earthquakes.
- Strain and friction builds over a long time in the subduction zone.

Volcanoes:
- Volcanic eruptions here are less frequent but more destructive and higher VEI
- The magma which feeds the volcanoes is created by the melting of the subducting oceanic plate.
- Creates composite volcanoes with high explosivity.

Question 19

What are convergent (collision) plate boundaries?

Answer 19

These are formed when 2 continental plates move towards each other.

Question 20

What processes occur at convergent (collision) boundaries?

Answer 20

Earthquakes:
*high magnitude but less frequent earthquakes
*two continental crusts crunch into one another creating an uplift leading to the creation fold mountains

Volcanoes:
*No volcanic activity is found because lithosphere is neither created or subducted