Continental Drift Flashcards
Give evidence that Continental Drift Exists:
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Who proposed the Continental Drift?
Wegener in the 1900’s.
What are some species that could be found on multiple continents along the borders?
Cynognathus can be found in South America and Africa. Lystrosaurs can be found in Africa, India, and Antartica. Mesosaurus can be found in South America and Africa. And Glossopteris (plant) can be found in South America, Africa, India, Antartica, and Australia.
What is Paleomagnetism?
The study of the earth’s magnetism at the time of rock formation.
How does magnetism affect rock?
Magnetized iron-rich minerals in rocks will capture the direction of the Earth’s magnetic poles at the time of the rock’s formation. Once hardened, this direction remains in the rock.
How does paleomagnetism prove Continental Drift?
The direction of the iron enriched mineral in the rock does not match the direction of rocks formed today. This suggests that either the magnetic poles have moves, or the continents themselves moved.
During the 1950s and 1960s, what did scientists discover about the ocean floor?
Rock samples found on the ocean floor would never be older than 180-200 million years ago.
Who proposed the seafloor spreading hypothesis?
Harry Hess in the early 1960s.
What is the seafloor spreading hypothesis?
As seafloor moves away from ocean ridges, newly formed oceanic crust replaces it. Lava rises and cools, filling the crack made by the ocean floor pulling apart. This cycle it continuous. The older oceanic crust is consumed by deep ocean trenches.
What type of transform fault are ocean ridges?
Divergent
What is Geomagnetic Reversal?
When the magnetic poles of earth reverse polarity. The north pole becomes the south, and vise versa.
How do we know Geomagnetic Reversal Occurs?
Geomagnetic Reversals are recorded in the ocean crust using magnetometers.
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