Geology Flashcard

Front

What is Wegener’s hypothesis of continental drift?

Back

The hypothesis that the continents once formed a single land mass, broke up, and drifted to their present locations.

Front

Why was Wegener’s hypothesis of continental drift originally rejected by geologists?

Back

Wegener could not explain how the continents could move through the ocean floor.

Front

What are convection currents?

Back

Movements in the mantle that occur in circular motions due to heat from the Earth's interior.

Front

What drives mantle convection?

Back

The heat that drives mantle convection comes from the cooling of Earth’s interior and the decay of radioactive isotopes.

Front

What causes magma to rise towards the surface in a volcano?

Back

Magma is less dense than the surrounding rock, causing it to rise.

Front

What is the theory of plate tectonics?

Back

The theory that the Earth's outer shell is divided into several plates that glide over the mantle.

Front

What is seafloor spreading?

Back

The process by which new oceanic crust is formed at mid-ocean ridges and older crust moves away.

Front

What are tectonic plates?

Back

Large pieces of the Earth's lithosphere that move and interact at their boundaries.

Front

What is subduction?

Back

The process where one tectonic plate moves under another and sinks into the mantle.

Front

What is a transform boundary?

Back

A type of plate boundary where two plates slide past each other horizontally.