Plate Boundaries
What happens when two oceanic plates meet at a convergent boundary?
One of the plates is Subducted under the other.
What is continental crust?
Thickest part of earth's crust. Less dense than oceanic crust.
How are deep ocean trenches formed?
Two plates moving toward each other collide and one subducts under the other, and bends forming an ocean trench.
A process where a part of earth's crust slides into the mantle and is recycled.
Convergent boundry Oceanic/Continental, what happens?
The oceanic plate subducts under the continental plate because it denser and thinner.
What happens at a Continental-Continental convergent boundary?
The two push against each other making mountain ranges until one is subducted.
What is Oceanic crust?
Denser and thinner than Continental crust. Makes up ocean floor/tectonic plates.
How are mid-ocean ridges formed?
Two oceanic plates move away from each other in opposite directions.
Molten rock that slides up out of the mantle to form land.
Magma
How is new crust formed?
Magma swells up from inside the earth's mantle and cools creating new crust.
What happens when two oceanic plates are divergent?
They move in opposite directions of each other forming rift valleys.
How do scientists know oceanic crust moves?
Seafloor spreading. Using SONAR. Differing magnetic readings.
How are volcanoes formed?
Continental plates move away from each other as magma comes up creating a volcano.
The process were tectonic plates split apart from each other, and create ocean ridges.
Sea floor spreading.
Who is Alfred Wegener?
The first person to have an accurate theory on tectonic plates.
What happens when two continental plates are divergent?
The crust completely breaks apart as magma pushes its way to the top.
How do scientists get a relative age for oceanic crust?
The older is farther from Oceanic ridges. Seismic dating.
How are mountains formed?
Continental plats push into each other head on and squish together and forms a mountain.
The mantle's convective motion causing the earth's crust to break apart.
Convection Currents
A supercontinent that is the base for all continents today.
Pangaea
What is a transform boundary/what happens?
Two plates slide past each other parallel.
Why does oceanic crust subduct beneath continental crust?
It is denser and thinner. Being dense makes it sink easier and it being thinner means it can't get over the thick continental crust.
How are rift valleys formed?
The separation of two plates by sea floor spreading.
What makes these 3 places similar, the Circum Pacific belt, the Alpide belt, and the mid-Atlantic Ridge?
They are all Earthquake-prone Areas.
How far does the plates move on average per year?
5cm per year.