Earth and Space Unit 5 (Earth's Structure) Review

Divergent Boundary

A tectonic plate boundary where two plates move away from each other, often resulting in the formation of new crust in the form of rift valleys on land and ridges underwater.

Oceanic-Oceanic Convergent Boundary

A tectonic plate boundary where two oceanic plates collide, leading to the subduction of one plate beneath the other, often forming deep ocean trenches and underwater volcanoes.

Oceanic-Continental Convergent Boundary

A tectonic plate boundary where an oceanic plate collides with a continental plate, resulting in the subduction of the denser oceanic plate under the less dense continental plate, which can create mountain ranges, volcanic activity, and deep ocean trenches.

Continental-Continental Convergent Boundary

A tectonic plate boundary where two continental plates collide, leading to the formation of mountain ranges and significant geological uplift, as neither plate is subducted.

Transform Boundary

A tectonic plate boundary where two plates slide past each other horizontally, causing earthquakes and fault lines, but no significant geological features are created.

Rift fault

Divergent faults in which the material between sinks, creating a rift

Ridge

Divergent faults in which new material is created from rising magma that cools when it touches water

Reverse/thrust fault

A convergent boundary in which the middle crumples upward, creating folded mountains

Subduction zone

A convergent boundary where the denser tectonic plate moves under the other, creating coastal mountain ranges

Strike-slip fault

A transform boundary that causes linear shifts and earthquakes.

Hotspots

Active volcanoes that are not on plate boundaries

Volcano

Magma rises where Earth’s crust is weak at convergent or divergent boundaries.

Earthquake

Caused by built-up stress at a plate boundary and the sudden release of pressure, sending seismic waves through Earth.

Tsunami

MASSIVE waves usually caused by underwater earthquakes.

Mountains

They rise up as two tectonic plates collide at convergent boundaries.

Inner core

The innermost layer of Earth, made of solid iron, nickel, and other heavy metals.

Outer core

The churning of liquid iron, nickel, and other heavy metals in this layer of Earth creates the planet’s magnetic field.

Mantle

The layer of Earth that is made of viscously solid molten rock and lots of silicates

Crust

The outermost layer of Earth, made of solid rock, that comes in two types, oceanic (denser because of the pressure of ocean water) and continental.

Mantle convection

The movement of materials in the mantle. Lower mantle gets heated, rises, then cools off and sinks, similar to how a lava lamp works.

Slab pull

The pulling force exerted by a falling cold and dense oceanic plate.

Ridge push theory

When new crust forms on a ridge, old crust is pushed away

Wind erosion

Particles get moved from the force and kinetic energy of the wind

Water erosion

Moves particles with kinetic energy of rain, rushing river, mechanical energy of surface runoff, etc.

Gravity erosion

Mass moves down steep slopes due to gravity, e.g. in a landslide

Freeze-thaw weathering

When water seeps into cracks, freezes, and expands, breaking things. This process is what causes potholes to form.

Onion skin weathering/exfoliation

The process of layers of rock flaking off

Chemical weathering

When a reaction causes a chemical change, e.g. acid rain

Biological weathering

When a living thing breaks up rocks, e.g. tree roots, animals

Glaciation

When the weight of a glacier drags it downward, creating glacial sheets and U-shaped valleys. Then our climate warms, glaciers melt, causing erosion, weathering, and for the sea levels to rise.

Alfred Wegener’s evidence for his Theory of Continental Drift

Fossilized tropical plants in cold climates, mountain and fossil patterns line up on different continental coastlines, and continents fit together like puzzle pieces (especially South America & Africa)

Pangea

A supercontinent from 250 million years ago that was made up of all the different continents