UNIT 4 - AP Environmental Science (In Progress)

APES 202526

Core

The innermost zone of Earth’s interior, composed mostly of iron and nickel. It includes a liquid outer layer and a solid inner layer.

Mantle

The layer of Earth above the core, containing magma, the asthenosphere, and the solid upper mantle.

Magma

Molten rock.

Asthenosphere

The layer of Earth located in the outer part of the mantle, composed of semi-molten rock.

Lithosphere

The outermost layer of Earth, including the solid upper mantle and crust.

Plate tectonics

The theory that the lithosphere of Earth is divided into plates, most of which are in constant motion.

Earthquake

A sudden movement of Earth’s crust caused by a release of potential energy from the movement of tectonic plates.

Hot spots

In geology, a place where molten material from Earth’s mantle reaches the lithosphere.

Volcano

A vent in the surface of Earth that emits ash, gases, or molten lava.

Tsunami

A series of waves in the ocean caused by seismic activity or an undersea volcano that causes a massive displacement of water.

Divergent boundary

An area below the ocean where tectonic plates move away from each other.

Seafloor spreading

Caused by a divergent boundary, in which rising magma forms new ocean crust on the seafloor at the boundaries between those plates.

Convergent boundaries

An area where one plate moves toward another plate and collides.

Subduction

The process in which the edge of an oceanic plate moves downward beneath the continental plate and is pushed toward the center of Earth.

Island arcs

A chain of islands formed by volcanoes as a result of two tectonic plates coming together and experiencing subduction.

Collision zone

An area where two continental plates are pushed together and the colliding forces push up the crust to form a mountain range.

Transform boundary

An area where tectonic plates move sideways past each other.

Fault

A fracture in rock caused by a movement of Earth’s crust.

Igneous rocks

Rock formed directly from magma.

Sedimentary rocks

Rock that forms when sediments such as muds, sands, or gravels are compressed by overlying sediments.

Metamorphic rocks

Rock that forms when sedimentary rock, igneous, or other metamorphic rock is subjected to high temperature and pressure.

Rock cycle

The geologic cycle governing the constant formation, alteration, and destruction of rock material that results from tectonics, weathering, and erosion among other processes.

Physical weathering

The mechanical breakdown of rocks and minerals.

Chemical weathering

The breakdown of rocks and minerals by chemical reactions, the dissolving of chemical elements from rocks, or both these processes.

Acid precipitation

Precipitation high in sulfuric acid and nitric acid. Also known as acid rain.

Erosion

The physical removal of rock fragments from a landscape or ecosystem.

Parent material

The underlying rock material from which the inorganic components of a soil are derived.

Horizons

A horizontal layer in a soil defined by distinctive physical features such as color and texture.

O horizon

The organic horizon at the surface of many soils, composed of organic detritus in various stages of decomposition.

Humus

The most fully decomposed organic matter in the lowest section of the O horizon.

A horizon

Frequently the top layer of soil, a zone of organic material and minerals that have been mixed together. Also known as Topsoil.

E horizon

A zone of leaching, or eluviation, found in some acidic soils under the O horizon or, less often, the A horizon.

B horizon

Commonly known as subsoil, a soil horizon is composed primarily of mineral material with very little organic matter.

C horizon

The least-weathered soil horizon, which always occurs beneath the B horizon and is similar to the parent material.

Porosity

The size of the air spaces between particles.

Water holding capacity

The amount of water a soil can hold against the draining force of gravity.

Permeability

The ability of water to move through the soil.

Cation exchange capacity (CEC)

The ability of a particular soil to absorb and release cations.

Base saturation

The proportion of soil bases to soil acids, expressed as a percentage.

Watersheds

All land in a given landscape that drains into a particular stream, river, lake, or wetland.