U5 Notes + Earths Interior Diagram Flashcards
what does the theory of tectonic plates explain?
it explains the formation and location of Earths major landforms
what does tectonic mean?
comes from the greek word for mason
what is convection?
when heat is carried or transferred from hotter areas to cooler areas by the movement of fluids or gas
Where did the idea of plate movements come from?
Alfred Wegner started it in 1915 with his theory of Continental drift
How many major lithospheric plates are there?
- African
- Antarctic
- Eurasian
- Indo-Australian
- Pacific
- North American
- South American
what are Plate Boundaries?
The places where lithospheric plates touch
What are the three types of plate boundaries?
- Divergent
- Convergent
- Transform
What is a divergent boundary?
The place where to plates move away from each other
What landforms are created by a divergent boundary?
- A mid-ocean ridge ( an underwater mountain chain)
- A rift valley with sets of parallel ridges and valleys to either side
What is a ridge push?
the shoving force created as new lithosphere constantly fills in the gap between two diverging plates, this force helps push each plate away from its source
what is a convergent boundary?
the place where two plates come together and slowly smash into each other
What landforms are created by a convergent boundary?
- a deep ocean trench & an arc of volcanic islands
- a deep ocean trench & an arc of continental volcanoes
- a continental mountain range & a high plateau
What is subduction?
when old, cold, and dense oceanic lithosphere converges with another plate and slides under it
Why does subduction happen?
When two plates converge the older plate sinks back down into the asthenosphere while the younger plate floats to the top
what is slab-pull?
the tugging force created by gravity as the leading edge of the plate subducts, this force helps drag the entire plate away from its source