Plate Boundaries
What should the Atlantic Ocean look like in 100,000 years?
it will be wider
What is special about the mountains in Europe and North America?
They are made of the same rock and formed around the same time
How many layers of the earth are there?
4
What are tectonic plates?
The crust of the earth cracked into pieces
Does the athesnopshere move quickly or slowly?
slowly
What forms at convergent boundaries?
mountains or volcanoes
What was the major piece of fossil evidence that was found at first?
the same animal fossils in South America and Africa
Which layer of the earth is the thinnest?
the crust
What are the three types of plate boundaries?
Convergent, divergent, and transform
Where do convection currents occur?
the asthenosphere
Why do earthquakes occur at plate boundaries?
Tension builds as the plates move
What was the name of the scientist that first proposed the theory of plate tectonics?
Alfred Wegener
About how thick is continental crust?
25 miles
What is a convection current?
Hot magma coming up cooling then sinking back down toward the core
What is the 25,000 mile ring of volcanoes and earthquakes called?
The ring of fire
What do the plates do at a transform boundary?
Slide past each other
What was the supercontinent 250 million years ago called?
Pangea
What layer was thought to be liquid but is actually a solid?
The inner core
What forms when a oceanic plate slides under a continental plate?
a subduction zone
the asthenosphere carries them
What kind of boundary is responsible for seafloor spreading?
Divergent
What did glaciers leave behind on many continents that shows they were once part of a supercontinent?
Glacial till and streaked rocks
What layer makes up 84% of the earth?
the mantle
What is the lithosphere?
the crust and solid part of the mantle
How far to tectonics plates move in a year?
3-5 centimeters