Unit 4

The upward movement of ocean water toward the surface as a result of diverging currents.

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

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

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

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

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

Precipitation high in sulfuric acid and nitric acid.

A pale blue gas composed of molecules made up of three oxygen atoms (O3).

Pipes and canals that move water from where it is abundant to areas where it is scarce.

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

The layer of the atmosphere above the stratosphere, extending roughly 50 to 85 km (31–53 miles) above the surface of Earth.

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

A convection current in the atmosphere that lies between Hadley cells and polar cells.

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

The deflection of an object’s path due to the rotation of Earth.

Following an El Niño event, trade winds in the South Pacific reverse strongly, causing regions that were hot and dry to become cooler and wetter.

A layer of the atmosphere closest to the surface of Earth, extending up to approximately 16 km (10 miles).

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

The latitude that receives the most intense sunlight, which causes the ascending branches of the two Hadley cells to converge.

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

Molten rock.

The size of the air spaces between particles.

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

An oceanic circulation pattern that drives the mixing of surface water and deep water.