Lecture 5: Part 2: Plate Tectonics Flashcards
Lithosphere in mid ocean
Lithosphere is ductile not liquid
Forming new lithosphere
Oceanic crust is constantly the same
Lithosphere becomes denser and heavier further away from crust
Convergent boundary
Two plates move toward one another
Can cause subduction or continental collision depending on the two crusts
Can you continuously create crusts?
No, if one is created one mustn’t also be destroyed.
What occurs to the downgoing plate in subduction.
The downgoing plate will slowly sink down into the astheneosphere and changes direction over time.
Wadati-Benioff zone
Defines the position of the downgoing tectonic plate above a depth of `660km. (Earthquakes cant be generated below 660km)
Earthquakes can be generated below 660km; true or false.
True
Transform boundaries
Plates slide past one another along a vertical (transform) fault plane.
What is a triple junction.
Tripl- three
Junction- point
A place where three plates intersect at a point
What are the different types of tectonics?
Plate boundary tectonics and intraplate tectonics
Hot-spot volcanoes
An activity within a tectonic plate. It is associated plumes of heat in the mantle. They form localized
What is the most famous example of hot-spot volcanoes?
Hawaiian islands
What does direction of plate motion help us determine?
Allows us to tell us past and future of earth. Plate motion tells us the age of hot-spot volcanoes.
Seamount/guyot
A hot-spot volcano that erodes and subsides that end up sinking below sea level to form seamount and guyot are flat-topped seamounts
What is continental collision?
When there is no more oceanic plates ****
Plate driving force:
Slab pull develops because old oceanic lithosphere is more dense than the underlying asthenosphere, causing it to sink
Why is the mid-ocean ridge always in the middle of an ocean?
Subduction speed governs the mid-ocean ridge’s position.
