Unit 4 Flashcards
Upwelling
The upward movement of ocean water toward the surface as a result of diverging currents.
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.
Collision zone
An area where two continental plates are pushed together and the colliding forces push up the crust to form a mountain range.
C horizon
The least-weathered soil horizon, which always occurs beneath the B horizon and is similar to the parent material.
B horizon
Commonly known as subsoil, a soil horizon is composed primarily of mineral material with very little organic matter.
Lithosphere
The outermost layer of Earth, including the solid upper mantle and crust.
Acid precipitation (Acid rain)
Precipitation high in sulfuric acid and nitric acid.
Ozone
A pale blue gas composed of molecules made up of three oxygen atoms (O3).
Aqueducts
Pipes and canals that move water from where it is abundant to areas where it is scarce.
Island arc
A chain of islands formed by volcanoes as a result of two tectonic plates coming together and experiencing subduction.
Mesosphere
The layer of the atmosphere above the stratosphere, extending roughly 50 to 85 km (31–53 miles) above the surface of Earth.
Base saturation
The proportion of soil bases to soil acids, expressed as a percentage.
Ferrell cell
A convection current in the atmosphere that lies between Hadley cells and polar cells.
Water holding capacity
The amount of water a soil can hold against the draining force of gravity.
Coriolis effect
The deflection of an object’s path due to the rotation of Earth.
La Niña
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.
Troposphere
A layer of the atmosphere closest to the surface of Earth, extending up to approximately 16 km (10 miles).
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.
Intertropical convergence zone (ITCZ)
The latitude that receives the most intense sunlight, which causes the ascending branches of the two Hadley cells to converge.
O horizon
The organic horizon at the surface of many soils, composed of organic detritus in various stages of decomposition.
Magma
Molten rock.
Porosity
The size of the air spaces between particles.
Chemical weathering
The breakdown of rocks and minerals by chemical reactions, the dissolving of chemical elements from rocks, or both these processes.
Thermohaline circulation
An oceanic circulation pattern that drives the mixing of surface water and deep water.
Volcano
A vent in the surface of Earth that emits ash, gases, or molten lava.
Humus
The most fully decomposed organic matter in the lowest section of the O horizon.
Seafloor spreading
Caused by a divergent boundary, in which rising magma forms new ocean crust on the seafloor at the boundaries between those plates.
Watershed
All land in a given landscape that drains into a particular stream, river, lake, or wetland.
Tsunami
A series of waves in the ocean caused by seismic activity or an undersea volcano that causes a massive displacement of water.
Cation exchange capacity (CEC)
The ability of a particular soil to adsorb and release cations.
Carbon sequestration
The capture and long-term storage of carbon dioxide from the atmosphere.
A horizon (Topsoil)
Frequently the top layer of soil, a zone of organic material and minerals that have been mixed together.
Polar cell
A convection current in the atmosphere, formed by air that rises at 60° N and 60° S and sinks at the poles, 90° N and 90° S.
Thermosphere
The layer of the atmosphere above the mesosphere, extending 85 to 600 km (53–375 miles) above the surface of Earth.
Adiabatic heating
The heating effect of increased pressure on air as it sinks toward the surface of Earth and decreases in volume.
Plate tectonics
The theory that the lithosphere of Earth is divided into plates, most of which are in constant motion.
Albedo
The percentage of incoming sunlight reflected from a surface.
Exosphere
The outermost layer of the atmosphere which extends from 600 to 10,000 km (375–6,200 miles) above the surface of Earth.
Divergent boundary
An area below the ocean where tectonic plates move away from each other.
Insolation
Incoming solar radiation, which is the main source of energy on Earth.
Transform boundary
An area where tectonic plates move sideways past each other.
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.
Hot spot
In geology, a place where molten material from Earth’s mantle reaches the lithosphere.
Asthenosphere
The layer of Earth located in the outer part of the mantle, composed of semi-molten rock.
Adiabatic cooling
The cooling effect of reduced pressure on air as it rises higher in the atmosphere and expands.
Hadley cell
A convection current in the atmosphere that cycles between the equator and 30° N and 30° S.
Convergent boundary
An area where one plate moves toward another plate and collides.
Fault
A fracture in rock caused by a movement of Earth’s crust.
E horizon
A zone of leaching, or eluviation, found in some acidic soils under the O horizon or, less often, the A horizon.
Permeability
The ability of water to move through the soil.
Igneous rock
Rock formed directly from magma.
Sedimentary rock
Rock that forms when sediments such as muds, sands, or gravels are compressed by overlying sediments.
Saturation point
The maximum amount of water vapor in the air at a given temperature.
Gyre
A large-scale pattern of water circulation that moves clockwise in the Northern Hemisphere and counterclockwise in the Southern Hemisphere.
Erosion
The physical removal of rock fragments from a landscape or ecosystem.
Mantle
The layer of Earth above the core, containing magma, the asthenosphere, and the solid upper mantle.
Physical weathering
The mechanical breakdown of rocks and minerals.
Latent heat release
The release of energy when water vapor in the atmosphere condenses into liquid water.
Parent material
The underlying rock material from which the inorganic components of a soil are derived.
Atmospheric convection current
Global patterns of air movement that are initiated by the unequal heating of Earth.
Stratosphere
The layer of the atmosphere above the troposphere, extending roughly 16 to 50 km (10–31 miles) above the surface of Earth.
Rain shadow
A region with dry conditions found on the leeward side of a mountain range as a result of humid winds from the ocean causing precipitation on the windward side.
Metamorphic rock
Rock that forms when sedimentary rock, igneous rock, or other metamorphic rock is subjected to high temperature and pressure.
Earthquake
A sudden movement of Earth’s crust caused by a release of potential energy from the movement of tectonic plates.
Horizon
A horizontal layer in a soil defined by distinctive physical features such as color and texture.
El Niño–Southern Oscillation (ENSO)
A reversal of wind and water currents in the South Pacific.
