Seafloor Spreading Flashcards
You can't mention Continental Drift without mentioning Seafloor Spreading! It's getting super deep!
What is seafloor spreading?
It’s an action that happens at mid-ocean ridges where new oceanic crust comes up.
What is subduction?
It’s when 2 convergent plates meet where one is an oceanic plate and one is a continental plate, the less denser one goes under the less dense plate.
What is an example of seafloor spreading?
The Atlantic Ocean is an example, it’s getting bigger because of the mid-Atlantic ridge. The Pacific Ocean is an example, it’s getting smaller because it’s subducting into the mantle.
What are some evidences for seafloor spreading?
Pillow shaped rocks, magnetic strips, and Drilling Samples.
What are magnetic stripes?
Magnetic stripes are rocks on the ocean floor which contain Iron. These rocks are first molten material, then they cool and as it cools, the iron bits inside it point to Earth’s magnetic poles. The magnetic stripes will soon reverse themselves and North will be South, and South will be North.
What was the last reversal of the magnetic stripes?
780,000 years ago.
What are pillow shaped rocks?
Molten lava that hardened quickly.
What do pillow shaped rocks show about seafloor spreading?
That molten material exploded a lot by the mid-ocean ridges
