The Dynamic Earth Flashcards
Outer section of Earth (crust & upper mantle are called)
Lithosphere
Average plate movement speed
5-10 cm per year
Theory proposed by Alfred Wegener
Continental drift, all continents once together but drifted apart
Evidence for continental drift
- Land masses fit together
- Similar fossil records across multiple continent
- Magnetic alignment of rocks
How has Continental drift affected Fauna and Flora
If a continent is separated for a large period of time it allows for unique flora and fauna to evolve in unique conditions
Define subduction
1 plate moves under another due to a convergent boundary.
The mantle is apart of which inner section
Asthenosphere
What causes convection currents
Hot less dense magma rises while cooler magma sinks and is heated by the earth’s core. This creates a current moving in a cyclical motion
Oceanic or Continental:
Which is denser
Oceanic
Oceanic or Continental:
Which is older
Continental
Oceanic or Continental:
Which has a higher basalt content
Oceanic
Oceanic or Continental:
Which is more likely to be subducted
Oceanic
Divergent boundaries
Involves spreading, creates ridges, constructive and creates volcanic activity
Convergent boundries
Involves subduction, creates trenches, destructive and creates volcanic activity
Transform boundries
Involves lateral sliding, conservative and creates earthquakes
Explain magnetic stripping
Magnetic striping is produced from the generation of magma at mid-ocean ridges during alternating periods of the Earth’s magnetic field
Explain sea floor spreading
As new sea floor is created from divergent boundary the older rock is pushed away.
Why do convergent boundaries create more explosive volcanoes than divergent boundaries
Convergent boundaries push more rock downwards creating greater pressure and greater force from the volcanoes.
Describe the process of folding
The forces on the layers are so large that layers of rocks bend and crumple without breaking and instead fold in on itself
Difference between anticline and syncline
Anticlines go upwards while synclines bend downwards
How are horsts formed
A block of land is pushed upwards by the forces below
Describe transform faults
A small crack caused by two plates sliding past each other
Describe reverse faults
Rocks have been forced upwards due to the subducting plates pushing both sides together
Describe normal faults
Rocks slip downwards due to the rocks being stretched out
