4.1 - Plate Tectonics Flashcards
1
Q
Name the Earth’s structure in order
A
- Crust
- Lithosphere
- Asthenosphere
- Mantle
- Core
2
Q
Name and describe the earth’s structure
A
- Crust - very outer layer of the lithosphere, earth’s surface
- Lithosphere - thin, brittle layer of rock floating on top of mantle (broken up into tectonic plates)
- Asthenosphere - solid, flexible outer layer of mantle, beneath the lithosphere
- Mantle - liquid layer of magma surrounding core, kept liquified by intense heat from core
- Core - Dense mass of solid nickel, iron, and radioactive elements that release massive amount of heat
3
Q
3 types of plate boundaries
A
- Divergent Plate Boundary
- Convergent Plate Boundary
- Transform Fault Plate Boundary
4
Q
Explain Divergent Plate Boundary
A
- Plates move away from each other
- Risin magma plum from mantle forces plates apart
- Forms in - mid-Atlantic ridges, volcanoes, seafloor spreading, and rift valleys (on land)
5
Q
Describe convergent plate boundary
A
- plates move towards each other
- leads to subduction (one plate being forced beneath another)
6
Q
Describe transform fault plate boundary
A
- plates slide past each other in opposite directions
- found in - earthquakes
7
Q
What cycle is with divergent plate boundaries?
A
Convection Cycle
8
Q
Explain the convection cycle
A
- Magma is heated by the earth’s core and rises through the lithosphere
- Rising magma cools and expands, forcing oceanic plates apart
-Creates mid-ocean ridges, volcanoes, spreading zones (seafloor spreading) - Magma cools and solidifies into new lithosphere
- Spreading magma causes oceanic plates to be pushed under each other (converging/subduction zone)
- The sinking oceanic plate melts back into magma
- Forces magma up, creating narrow, coastal mountains (Andes) and volcanoes on land
9
Q
What is the Convection Boundary related to
A
Subduction Zone
10
Q
Name the 3 subduction zones
A
- Oceanic-Oceanic
- Oceanic-Continental
- Continental-Contental
11
Q
Explain Oceanic-Oceanic Subduction Zones
A
- one plate subducts underneath other
- forces magma up to lithosphere surface, forming mid ocean volcanoes/island arcs
- Where the two meet there is a dent in the ocean, called an off-shore trench
12
Q
Explain Oceanic-Continental Subduction zones
A
- dense oceanic plate subducts beneath continental plate and melts into magma
- Forces magma back up to the surface
- Creates costal mountains, volcanoes on land, trenches, and tsunami’s
13
Q
Explain Continental-Continental Subduction zones
A
- One plate subducts underneath other, forcing crust upwards
- Creates mountains
14
Q
Explain in detail transform Fault Boundary
A
- Plates sliding past each other in opposite directions creates a fault
- Earthquakes - most common activity
- Occurs when rough edges of plates get stuck on each other
- Pressure builds as plates keep sliding, but edges stay stuck
- When stress overcomes the locked fault, plates suddenly release, slide past each other and release energy that shakes the lithosphere
15
Q
What can a tectonics plate map predict?
A
- Ring of Fire: pattern of volcanoes all around pacific plate and offshore island arcs
- Transform faults: Likely location of earthquakes
- Hotspots: areas of especially hot magna rising up to the lithosphere (mid ocean islands; hawaii, iceland)
