Unit 4: Earth Systems and Resources

Flashcards connected to AP Environmental Science Unit 4 Topics

Asthenosphere

The soft, flexible upper layer of the mantle, on which the tectonic plates move.

Continental crust

The crust that comprises Earth’s continents. It is composed mainly of granitic rock, and it is less dense and thicker than oceanic crust.

Convection currents

The process by which less dense material rises and more dense material sinks. In Earth’s mantle hot rock rises and slightly cooler rock sinks.

Continental drift

The gradual movement of the continents across the earth's surface through geological time.

Convergent boundary

An area on Earth where two or more lithospheric plates collide. One plate eventually slides beneath the other, a process known as subduction.

Crust

The thin layer of rock that forms Earth’s outermost layer.

Divergent boundary

A boundary where two tectonic plates move away from each other.

Earthquake

A sudden movement of the Earth's lithosphere (its crust and upper mantle).

Extrusive rock

Igneous rocks formed when magma from the Earth's interior erupts onto the surface as lava and cools rapidly.

Fault

A fracture or zone of fractures in the Earth's crust where two blocks of rock can move relative to each other.

Geosphere

The core to the solid surface. The lithosphere is part of the geosphere.

Hot spot

A large plume of hot mantle material rising from deep within the Earth.

Inner core

Dense sphere of solid iron and nickel in the center of the Earth; the hottest part of Earth.

Igneous rock

Form when hot, molten rock crystallizes and solidifies.

Intrusive rock

Igneous rock that forms when magma is trapped deep inside the Earth, where it cools very slowly until it solidifies.

Island arc

A chain of islands that form as the result of volcanic activity when one tectonic plate slides underneath another.

Lava

Hot molten or semifluid rock erupted from a volcano or fissure, or solid rock resulting from cooling of this.

Lithosphere

The rigid outer part of the earth, consisting of the crust and upper mantle.

Mantle

The layer of hot, solid material between Earth’s crust and core.

Magma

Hot fluid or semifluid material below or within the earth's crust from which lava and other igneous rocks are formed on cooling.

Mesosphere

The solid lower layer of the mantle is located below the asthenosphere.

Metamorphic rock

Started out as some other type of rock, but have been substantially changed from their original igneous, sedimentary, or earlier metamorphic form.

Mid-ocean ridge

A divergent plate boundary where continental plates are moving apart.

Mountain

A landform that rises at least 1,000 feet (300 meters) or more above its surrounding area.

Oceanic crust

The crust that is found on the ocean floor. It is composed mainly of basaltic rock and is denser and thinner than continental crust.

Outer core

A fluid layer about 2,260 km (1,400 mi) thick, composed of mostly iron and nickel that lies above Earth's solid inner core and below its mantle.

Plate boundary

The border between two plates.

P-Waves

The first waves to arrive at a seismograph. These are the fastest seismic waves and can move through solid, liquid, or gas.

Rift valley

A lowland region that forms where Earth’s tectonic plates move apart, or rift.

Rock cycle

Describes transitions through geologic time among the three main rock types: sedimentary, metamorphic, and igneous.

Seafloor spreading

The process of tectonic plates splitting apart under the ocean, which is caused by mantle convection.

Sedimentary rock

Rock that has formed through the deposition and solidification of sediment, especially sediment transported by water, ice, and wind.

Seismic waves

A wave of acoustic energy that travels through the Earth.

Seismograph

An instrument that measures and records details of earthquakes, such as force and duration.

S-Waves

The second waves to arrive during an earthquake. They are much slower than P waves and can travel only through solids.

Subduction

The sideways and downward movement of the edge of a plate of the earth's crust into the mantle beneath another plate.

Subduction zone

The region where an oceanic plate sinks beneath a continental plate.

Tectonic plates

Massive slabs of solid rock made up of Earth's lithosphere (crust and upper mantle).

Transform boundary

Created when tectonic plates slide past each other horizontally along strike-slip faults or transform faults.

Trench

A long, narrow, deep depression in the ocean floor.

Volcano

A geological formation that occurs when molten rock, ash, and gases escape from the Earth's crust.