What is extensionism?
the required need for land bridges to explain the distribution of plants in the southern hemisphere
What is continental drift?
the movement of continents relative to each other
Tectonics
a branch of geology concerned with the structure of the crust of a planet or moon, especially the formation of folds and faults
Plate Tectonics
a tectonic mode characterized by a brittle lithosphere that fractures into plates
Why are plate tectonics significant?
because they are possibly only a thing on earth as far as we know, could be essential for life,
What did BC used to be?
a chain of tropical islands that then connected to the mainland
Where is the youngest ocean crust found?
mid-ocean ridges
What is the lithosphere?
crust + top of mantle
is brittle and fractures into plates
plate movement explains continental drift
How does mantle convection drive plate tectonics?
Driven by changes in density
Lower mantle is hot - less dense, buoyant/rises
Surface is cool - more dense, sinks
