Earth's Structure and Plate Tectonics Lecture

These flashcards review key concepts from the lecture on Earth’s structure and plate tectonics, including Earth’s layers, crust types, mantle dynamics, heat transfer, and plate boundary interactions.

What are the three main layers that make up Earth’s interior?

The crust, the mantle, and the core.

Which type of crust is thicker and less dense, continental or oceanic?

Continental crust is thicker (10–70 km) and less dense (buoyant).

Which type of crust is thinner and more dense, continental or oceanic?

Oceanic crust is thinner (~7 km) and denser, causing it to sink beneath continental crust.

What is the mantle primarily composed of and what is its physical state?

Very hot rock that is solid but capable of slow flow in certain zones.

What is the lithosphere and why is it important in plate tectonics?

The rigid outer layer consisting of the crust and the uppermost mantle; it forms the tectonic plates.

Where is the asthenosphere located and how does it behave?

It lies beneath the lithosphere in the upper mantle and behaves as a viscoelastic solid that can flow like silly putty.

Of which metals is Earth’s core mainly composed and how is it divided?

Mostly iron and nickel; it has a liquid outer core and a solid inner core.

What does the theory of plate tectonics explain?

The formation, movement, and subduction of Earth’s lithospheric plates.

Name the three modes of heat transfer.

Radiation, conduction, and convection.

What is radiation in the context of heat transfer?

The transfer of energy through empty space.

What is conduction in the context of heat transfer?

Heat transfer by direct contact of particles of matter.

What is convection in the context of heat transfer?

Heat transfer by the movement of a heated fluid (liquid or gas).

What drives convection currents in Earth’s mantle?

Heat from the core and lower mantle.

List the three main types of plate boundaries.

Divergent, convergent, and transform boundaries.

What occurs at a divergent boundary between oceanic plates?

Sea-floor spreading along a mid-ocean ridge as the plates move apart.

What typically happens when two oceanic plates converge?

One plate is subducted beneath the other, creating a trench and potential volcanic activity.

What landform is created when continental crust pulls apart at a divergent boundary?

A rift valley.

What characterizes a transform plate boundary?

Two plates slide horizontally past each other.

What major feature can form when two continental plates collide at a convergent boundary?

A mountain range.

Which layers together constitute the tectonic plates that move on Earth’s surface?

The crust and the uppermost part of the mantle, collectively called the lithosphere.