The Earth's Structure Flashcards
How hot is the Earth’s core?
6000 degrees C
What are the 4 parts of the Earth’s structure called?
The Core
The Outer Core
The Mantle (Asthenosphere)
The Crust (Lithosphere)
What is the outer core made up of?
Molten Iron and Nickel
How is the crust separated from the mantle?
By the MoHo discontinuity
Who came up with the plate tectonics theory?
Alfred Wegener
How did Wegener prove his theory?
Continental Fit - continental shelves
Geological - Mountains on different continents match with rocks of the same age
Biological - Fossils and plants
Climatological - Coal deposits
What is paleomagnetism?
When basalt erupts from a magma chamber and the magnetic field of the Earth aligns the magnetic minerals before they cool. There is a band of N/S rock orientation
How does a convection current work?
They move the magma in the mantle which in turn moves the plates.
Magma plumes heated by hotspots move magma up and tension is created. The plates then crack due to this tension.
What are the two types of rock?
Basalt - dense and cools quickly
Granite - rock that makes continents
What are the differences between granite and basalt?
Basalt - larger crystals, found on the ocean floor, rapid cooling, grey, dense
Granite - slower cooling, less dense, lots of small crystals, blue/pink, continental findings
What are the 4 plate margins?
Constructive - 2 plates move away
Destructive - 2 plates move towards (subduction and collision)
Conservative - 2 plates shear past
What is an extrusive landform?
When a landform has been squeezed out of the earth; magma plumes rise and break through (volcano)
What is an intrusive landform?
When magma doesn’t break through, it cools outside the surface of the earth and becomes granite. The rock weathers away. (Dartmoor)
Give two examples of extrusive landforms…
Fumeroles - vents of steam from the ground
Solfataras - hot springs of mud from the ground
