Exam 2- Plate Tectonics Flashcards
What is continental crust made out of?
Made of granite
What is oceanic crust made out of?
Made of basalt
Which is denser: continental or oceanic crust?
Oceanic crust is denser than continental
Why does plate tectonics matter?
It creates the world as we know it, but as the plates move/shift, it is very destructive as well.
how continents (and ocean crust) move
plate tectonics
What is mantle convection and how does it affect the movement of continents?
- Mantle convection: when warm rock rises and cool rock sinks; density decreases as rock gets hotter and they rise
- Plate movement is driven by mantle convection. (Causes the inclusion of mantle material into the crust at mid-ocean ridges and recycling of crust into the mantle at subduction zones)
What are the four basic parts of the structure of the Earth?
- Crust
- Mantle
- Outer Core
- Inner Core
What is the crust?
On the outside, the thinnest part; it’s where we live
What makes up the greatest thickness of the Earth and is underneath the crust?
Mantle
There is more (crust/mantle) than anything else.
Mantle
What is the most abundant rock type in the continental crust?
granite
Without the difference in density between the two crusts, we wouldn’t have _______ _______.
plate tectonics
What is the mantle? –> A (cool/hot) (solid/liquid)
A hot solid
What is the hottest part of the Earth?
The core
What is the mantle heated by?
the core
The density of rocks in mantle convection (increases/decreases) as they get hotter and rise.
decreases
What is the best evidence of movement happening within the Earth?
Earthquakes and volcanoes
Tectonic plates is parts of the (crust/mantle) moving in different directions from each other.
crust
What are the three possible movements at plate boundaries? Briefly describe them.
- Divergent: moving apart
- Convergent: moving together
- Transform: moving past
Which type of plate boundary creates new oceanic crust?
Divergent boundary
T or F: All divergent boundaries are underwater.
False; most are, but some aren’t
The divergent boundary is a place where the hot mantle is (rising/dropping). The _______ from below has broken the crust at a divergent boundary.
rising; pressure
What makes new crust at mid-ocean ridges?
Volcanic eruptions
What happens to old oceanic crust at a convergent plate boundary? Why?
Old oceanic crust is pushed down b/c the less dense crust goes over the denser crust (easier to make the more dense crust sink)
At convergent boundaries, movements must be _____ or ______.
up or down
When two plates collied, the (more/less) dense crust goes over the (more/less) dense crust. So, (oceanic/continental) goes over (continental/oceanic)
- less; more
- continental; oceanic
What happens when two oceanic crusts meet at a convergent boundary?
The younger oceanic crust goes over the older oceanic crust
At an ocean-continent convergence, the mantle is (cooling/melting) and this creates _________.
melting; volcanoes
T or F: Anywhere subduction is happening, there are going to be volcanoes.
True
At an ocean-continent convergence, what three things can appear and why?
- Volcanoes – mantle melting
- Earthquakes – pressure
- Mountains – pressure pushes up mountains
What happens when both plates at a convergent boundary are made of continental crust?
Neither continent can subduct (not dense enough), so there is no melting or volcanoes.
What is created at continent-continent convergent boundaries?
BIG mountains created by pressure because continental crust is getting super thick here (ex: Himalayan Mountains)
What is created at transform boundaries? What is not?
- Created: earthquakes (like San Andreas Fault)
- Not created: volcanoes, mountains (because nothing is pushed up or down)
