Plate Tectonics 2 Flashcards
What are the key differences between continental and oceanic crust?
Continental Crust: Thicker (30-70 km), less dense, made of granite
Oceanic Crust: Thinner (5-10 km), denser, made of basalt
What are 3 types of evidence supporting Wegener’s theory?
Fossil Evidence: Identical fossils (e.g., Mesosaurus) found on continents now separated by oceans.
Geological Evidence: Similar rock formations and mountain ranges on different continents (e.g., Appalachians in North America and Caledonides in Scotland).
Climatic Evidence: Evidence of glaciation in areas now near the equator and coal deposits in Antarctica.
How do plates move?
Ridge Push: Gravity pushes plates away from a mid-ocean ridge.
Slab Pull: The weight of a subducting plate pulls the rest of the plate downward.
Describe the 4 types of plate boundaries and associated movements.
Conservative Boundary: Plates slide past each other (e.g., San Andreas Fault).
Constructive Boundary: Plates move apart, and magma rises to form new crust (e.g., Mid-Atlantic Ridge).
Destructive Boundary: Oceanic plate subducts under continental plate, creating volcanoes and trenches (e.g., Andes Mountains).
Collision Boundary: Two continental plates collide, forming mountains (e.g., Himalayas).
What landforms are associated with each plate boundary?
Constructive Boundary: Mid-ocean ridges, rift valleys.
Destructive Boundary: Ocean trenches, volcanic arcs, fold mountains.
Collision Boundary: Mountain ranges.
Conservative Boundary: Fault lines.
