Chapter 1
The puzzle pieces beneath our feet
Chapter 2
When mountains blow their tops
Chapter 3
Shaking things up down below
Chapter 4
Coexisting with a restless planet
Ch 1 · The puzzle pieces beneath our feet
artiteacher Wegener noticed Africa and South America fit like puzzle pieces, which we now explain with 15 plates floating on a semi-liquid mantle.
Quiz
What was the name of the ancient supercontinent that Alfred Wegener proposed in 1912?
Quiz
Why did other scientists initially reject Alfred Wegener's continental drift theory in the early 20th century?
artiteacher Underwater volcanoes continuously create new oceanic crust, driving the Earth's tectonic conveyor belt.
Quiz
Who was the pioneering American geologist and cartographer who mapped the ocean floor and discovered the Mid-Atlantic Ridge?
Quiz
What happens to tectonic plates at a mid-ocean ridge during seafloor spreading?
Fun Fact
Plate speed: Tectonic plates move at about the same speed that human fingernails grow, roughly 1.5 inches (4 centimeters) every year.
Quiz
Which of the following is the deepest ocean trench on Earth, formed by a subduction zone?
Quiz
What is the geological term for a zone where one tectonic plate sinks beneath another into the mantle?
Glossary
tectonic plate (noun)
A massive, irregularly shaped slab of solid rock that makes up Earth's lithosphere. These geological slabs slowly drift, colliding to raise the Himalayas and sliding to cause California's earthquakes.
A massive, irregularly shaped slab of solid rock that makes up Earth's lithosphere. These geological slabs slowly drift, colliding to raise the Himalayas and sliding to cause California's earthquakes.
Quiz
What type of tectonic plate boundary occurs when two plates slide horizontally past one another, like at the San Andreas Fault?
Quiz
Approximately how fast do the tectonic plates along the San Andreas Fault move past each other on average each year?