Earth's Layers
What layer of the Earth do we live on?
The crust
Who created the theory of continental drift?
Alfred Wegener
Where does seafloor spreading occur?
Mid-ocean ridges
What is plate tectonics?
They theory that explains how and why the continents move.
What is caused by all three plate boundaries?
Earthquakes
What are the (3) different compositional layers of the Earth?
Crust, Mantle and Core
What evidence was used to justify the theory of continental drift?
Identical fossils on different continents, ages and types of rocks in the costal regions of different areas, matching coastlines, mountain chains that seem to continue on other continents
Who presented the idea of sea-floor spreading?
Harry Hess
What are the three types of plate boundaries?
convergent, divergent, and transform
What two features are created by divergent boundaries?
Continental and oceanic rifts
What are the (5) different structural layers of the Earth?
Lithosphere, asthenosphere, mesosphere, outer core, and inner core
What is the name of the supercontinent that was made up of all continents?
Pangea
What is sea-floor spreading?
The creation of new crust material where magma rises at a mid-ocean ridge that pushes away older rock from the ridge as the magma cools and solidifies.
What layer of the Earth do tectonic plates move on?
Asthenosphere
What unique type of feature is created by a convergent boundary of a continental and oceanic plate?
Island arc
What might be the cause of Earth's magnetosphere?
liquid iron in the outer core
Why was the theory of continental drift rejected?
There was no evidence to explain HOW, or by what FORCE the continents moved
Paleomagnetism
What are the major differences between continental and oceanic plates?
Continental plates are thicker and are under land masses, they are less dense and made of granite and andesite. Oceanic plates are thinner and under oceans, they are denser and made of basalt.
How are mountains formed?
Mountains are formed at convergent boundaries of two continental plates where the crust crumples as one plate subducts.
How does the asthenosphere differ from the mesosphere?
The asthenosphere is soft and made of partly melted hot rock that flows slowly. The mesosphere is hotter but more solid and does not flow as easily.
What is the mechanism that explained how the continents moved?
Sea-floor spreading
How does sea-floor spreading support the hypothesis of continental drift?
Since the sea-floor spreads and moves, the continents should also be able to move.
How does convection in the mantle move the plates?
The hot mantle rises through the cooler mantle causing the cooler, heavier material to sink or subduct. The process repeats creating a current like a conveyor belt
How are new oceans formed?
Two continental plates diverge and breakup a continent