Hi, my name is David Schultz.
Welcome to Our Earth, Its Climate, History, and Processes.
In this lecture,
I want to delve into plate tectonics in a little bit more detail.
And before I do that, I want to just make it clear on a couple of definitions.
The first one is continental drift.
This is a limited set of observations that relate
to the Peleo motion of continents, basically describing
the fact that continents have moved around on the planet.
This is Wegener's original hypothesis for explaining the observations that he saw.
But this is very clearly different than plate tectonics.
Plate tectonics is the theory that encompasses continental drift, but it also
encompasses the sea floor spreading, the mantle convection, the subduction zones.
The whole theory is wrapped up in this unifying theme called plate tectonics.
That the plates are lithospheric plates, crust and
upper part of the mantle, and that they are moving
on the surface of the Earth due to convection currents within the mantle.
Vine and Matthews, in 1963, explained that the magnetic
anomalies that they were observing were due to the creation of new crust during
periods of different phases of the earth's magnetic field.
Either pointing generally northward or pointing generally southward.
And that these anomalies then could be dated and determined.
Then how quickly the bands on the planet
then were being created under the water.
