Plate Dynamics Quiz Flashcards
Earth’s Layers aspects
Composition; Density, Pressure, Temperature vs depth
Continental Crust
Thicker, lower density, granitic (felsic)
Oceanic Crust
Thinner, higher density, basaltic (mafic)
Convection in the asthenosphere causes
the plates to move
Convection is the
circulation of a fluid due to differences in density.
Ocean ridges
hot magma rising
Ocean trenches
cool magma sinking
Earthquakes and volcanoes are more likely to occur
on or near plate boundaries (where 2 plates meet)
Convergent
Plates come together
which plate gets sub-ducted
oceanic plate
Ocean Trench forms from
convergent boundary
Divergent
Plates move apart as hot magma rises due to convection
Ocean Ridge & age of the seafloor:
Young crust at the ridge. Old as you move away
New, basaltic ocean crust forms here
Magnetic Polarity aspects
Pattern matches up on both sides of the ocean ridge
Evidence of seafloor spreading/divergent boundary/continental drift
Evidence that the magnetic field of the earth has reversed in the past
Transform
Plates slide past one another (e.g. San Andreas Fault)
Continental Drift
The movement of the tectonic plates
evidence for continental drift includes
Shape of continents
Matching of fossils on different continents.
Matching composition and age of rocks
Coal deposits and warm climate organisms (e.g. coral) in Antarctica, etc.
