Earth Science DBA Study Guide Flashcards

A vocabulary-style study guide focusing on continental drift, plate tectonics, seafloor features, and crust types.

Continental Drift

The theory that continents were once joined as Pangaea and drifted apart.

Pangaea

The name of the single landmass where all continents were once joined.

Alfred Wegener's Evidence

Coastline fit, matching fossils, matching rocks/mountains, and ancient climate patterns.

Wegener's Weakness

He could not explain the mechanism of how continents moved.

Lithosphere

The layer of Earth broken into tectonic plates that move over the mantle.

Convection currents

The main energy source driving plate movement, created by heat from Earth's interior.

Divergent Boundary

A boundary where plates move apart, creating mid-ocean ridges and new crust.

Convergent Boundary

A boundary where plates collide; an oceanic plate subducts beneath a continental plate, creating trenches, volcanoes, and mountains.

Transform Boundary

A boundary where plates slide past each other, causing earthquakes.

Seafloor Spreading

The process where new ocean floor forms at mid-ocean ridges and old ocean floor is recycled at ocean trenches.

Mid-ocean ridge

An underwater mountain chain where new crust forms.

Abyssal plain

Flat seafloor covering over $50\%$ of the ocean floor.

Continental shelf

The shallow edge of a continent.

Guyot

A flat-topped underwater volcano.

Trench

A deep ocean feature formed at subduction zones where old crust is destroyed.

Subduction

The process where one tectonic plate sinks beneath another.

Oceanic Crust

The type of crust that is younger, thinner, denser, and recycled.

Continental Crust

The type of crust that is older, thicker, and less dense.