Review of Plate Tectonics
Lithospheric plates slide on asthenosphere
About 1 to 10 cm/y
Main driving force is the sinking of oceanic lithosphere
Basalt to eclogite metamorphism
Plate boundaries versus plate interiors
3 types of plate boundaries
Origination of the Theory: Wegener’s Ideas
Continental fit
Ancient climate: glaciers and coal
Distribution of modern life forms
Related rocks across oceans
Distribution of fossils before and after Mesozoic
Modern Evidence
Paleomagnetism of continental rocks (1950s)
The seafloor: underwater mountain ranges (1950-1960s)
Age of the seafloor (1960s)
Magnetic stripes (1960s)
Distribution of earthquakes and types of faults (1960s)
Measuring Plate Motion: the Yardsticks
Relative motion
Transform faults give direction
Magnetic stripes give velocity
Absolute motion: hotspot tracks
Direct measurement: VLBI and GPS