Tectonics Flashcards
What are the 7 main tectonic plates?
Eurasian Plate
North American Plate
Pacific Plate
Indo-Australian Plate
South American Plate
Antarctic Plate
African Plate
What does it mean when Earthquakes and Volcanoes form ‘Intraplate’?
occur Inside the plate margins
What is the name of the 4 parts that make up the Earth?
Core
Mantle
Oceanic Crust
Continental Crust
What makes up the mantle?
The Asthenosphere
The Lithosphere
What is the Core?
Composited of Iron and Nickel
Responsible for Earths Magnetic field
What is the mantle?
Molten rock
high temp
slow flow
What is the Asthenosphere?
upper mantle
high temp (>1300)
convection occurs
What is the Lithosphere?
lower mantle
cool enough to prevent partial melting
rigid and brittle
What is the Oceanic Crust?
basaltic rock (mafic)
dense (2.9g/cm cubed)
What is the Continental Crust?
granitic rock (silicic)
less dense (2.7g/cm cubed)
When was Alfred Wegener Theory made?
1912
What does Alfred Wegener Theory suggest?
that the now-separated continents used to be joined
How are convection cells set up?
when hot, lower density material rises upwards and flows sideways as it cools down, making it become denser and sink back down
What happens when the convection current rises and a constructive plate?
rising magma and then eruption of lava
What did 2 geologies Vine and Mathew discover?
magnetic strips running parallel to the ridges
What is sea-floor spreading?
geological process
gradual addition of new oceanic crust in the ocean floor
What is subduction?
process where one plate sinks beneath another at a convergent plate boundary
Where does subduction occur?
destructive plate margin
What are the 3 types of volcanoes?
Composite
Cinder Cone
Shield
What is a Composite volcano?
Conical volcano
layers of solid lava flows mixed with layers of other rock
What is a Cinder Cone volcano?
no horizontal layers
steep conical hill of volcanic debris
What is a Shield volcano?
built entirely/mostly of lava fluid vents
huge ‘warrior’ shield
What are the 2 types of magma?
Mafic (Basaltic)
Silicic (Andesitic)
What are 4 characteristics of Mafic magma?
High density
High temp
Low viscosity
Non-explosive
What are 4 characteristics of Silicic magma?
Low density
Low temp
Thick viscosity
Explosive
What are the 4 types of Plate Boundaries?
Constructive
Destructive
Collision
Transform
What happens at a Constructive Plate boundary?
Plates move away from each other
-mid ocean ridges + Continental rift valleys
lithosphere pulled apart
What can occur at Constructive Plate boundaries?
Earthquakes
What happens at a Destructive plate boundary?
Two plates move towards each other and the denser oceanic plate is forced under the continental plate where it is subducted
