Layers of the Earth
This outermost, solid layer of Earth is broken into tectonic plates.
What is the crust?
This scientist first proposed that continents move over time.
Who is Alfred Wegener?
The theory that Earth’s lithosphere is broken into moving sections is called this.
What is plate tectonics?
This layer includes the crust and upper mantle and is broken into plates.
What is the lithosphere?
This underwater mountain range is where new oceanic crust is created.
What is the mid-ocean ridge?
Although it’s made of solid rock, this layer flows slowly and drives plate motion through convection.
What is the mantle?
Wegener’s hypothesis said that all continents were once joined in a supercontinent with this name.
What is Pangaea?
These movements in the mantle help drive the motion of tectonic plates.
What are convection currents?
The softer, plastic-like layer beneath the lithosphere.
What is the asthenosphere?
Harry Hess proposed sea-floor spreading after studying this mapping technology.
What is sonar?
This layer is liquid and made mostly of iron and nickel, creating Earth’s magnetic field.
What is the outer core?
This type of evidence from ancient land-based animals like Cynognathus helped support continental drift.
What are fossil clues?
These boundaries occur where plates move apart, forming rift valleys or mid-ocean ridges.
What are divergent boundaries?
Island arcs like Japan form at this type of convergent boundary.
What is oceanic–oceanic convergence?
This process adds new basalt as magma rises and solidifies.
What is sea-floor spreading?
This deepest layer is solid due to extreme pressure, even though it’s extremely hot.
What is the inner core?
Matching mountain ranges served as this type of evidence for drift.
What is geological (rock) evidence?
When oceanic crust sinks beneath continental crust, this process occurs.
What is subduction?
The Himalayan Mountains formed from this type of collision.
What is continental–continental convergence?
These patterns of magnetic stripes provide evidence for spreading.
What are magnetic reversal patterns?
This geologic process occurs in the mantle and is responsible for changing features on Earth's surface.
What is convection?
One reason Wegener’s hypothesis wasn’t accepted was his inability to explain this.
What is a driving force explaining how continents moved (convection)?
This type of boundary forms where plates slide past each other.
What is a transform boundary?
These long, deep features mark where oceanic plates sink downward.
What are deep-ocean trenches?
Sea-floor spreading explains why oceanic crust is youngest here and oldest here.
What is: youngest at ridges, oldest near trenches?