Plate Tectonics Flashcards
Who proposed the Theory of Continental Drift?
Alfred Wegener
What was the supercontinent called that existed over 200 million years ago?
Pangea
What are three pieces of evidence for Continental Drift?
Puzzle-like fit of continents, similar mountain ranges, matching fossils
What does the Theory of Plate Tectonics state?
Earth’s surface is made of moving rigid plates that shift over the mantle.
What does ‘tectonic’ refer to?
Forces that shape Earth’s surface and rock formations.
What is the largest tectonic plate?
Pacific Plate
What is the smallest tectonic plate?
Juan de Fuca Plate
Name the seven major tectonic plates.
African, Antarctic, Eurasian, Indo-Australian, North American, Pacific, South American
What is the lithosphere?
Rigid crust and upper mantle where tectonic plates are found
How is oceanic crust different from continental crust?
Oceanic = thinner & denser; Continental = thicker & less dense
What is the asthenosphere?
Hot, flowing layer beneath the lithosphere that moves plates
What is a plate boundary?
Where two tectonic plates meet
What happens at a divergent boundary?
Plates move apart; mid-ocean ridges or rift valleys form
What happens at a transform boundary?
Plates slide past each other; causes earthquakes
What happens at a convergent boundary?
Plates collide; can cause subduction, trenches, volcanoes, or mountains
What is subduction?
When a denser plate slides beneath a less dense plate
Example of oceanic-continental convergence
Marianas Trench, Mt. Saint Helens
Example of continental-continental convergence
Formation of mountain ranges
What tools do scientists use to measure plate movement?
Satellites
What causes tectonic plates to move?
Convection currents in the mantle
What is the Ring of Fire?
Zone around the Pacific Ocean with frequent earthquakes and volcanoes
What is a hot spot?
A fixed magma source forming volcanoes/islands (e.g., Hawaii)
Is the Theory of Plate Tectonics final?
No, it’s still being revised as new discoveries are made
