NEW Unit 4 APES Miller 7920

Divergent boundaries

Plate tectonic boundary where lithospheric plates are moving apart.

Convergent boundaries

Places where tectonic plates are coming together

Transform boundaries

Places where tectonic plates slide along beside one another as they move

Earthquake

The shaking that results from the sudden release of energy and movement of rock beneath Earth's surface.

Volcano

a mountain or hill, typically conical, having a crater or vent through which lava, rock fragments, hot vapor, and gas are being or have been erupted from the earth's crust.

Ring of fire

A major belt of volcanoes and earthquakes that rims the Pacific Ocean

Island arc

A string of islands formed by the volcanoes along a deep ocean trench

Rift valley

A deep valley that forms where two plates move apart

Hot spot

An area where magma from deep within the mantle melts through the crust above it

Crust

The thin and solid outermost layer of the Earth above the mantle

Mantle

The layer of hot, semi-solid material between Earth's crust and core.

Core

The central part of the earth below the mantle

Lithosphere

A rigid layer made up of the uppermost part of the mantle and the crust.

Asthenosphere

The soft layer of the mantle on which the lithosphere floats.

Convection currents

Circular currents in the mantle caused by the magma being heated by the core off the Earth.

Magma

Molten rock beneath the earth's surface

Lava

Magma that reaches Earth's surface

Mid-ocean ridges

long chains of mountains on the ocean floors where tectonic plates meet

Subduction zone

the region where an oceanic plate sinks down into the asthenosphere at a convergent boundary, usually between continental and oceanic plates

Tectonic plate

Sections of the Earth's crust that move due to convection currents.

Richter scale

A scale that rates an earthquake's magnitude based on the size of its seismic waves.

Fault

A break in the earth's crust

Pangea

A supercontinent containing all of Earth's land that existed about 225 million years ago.

Tsunami

A giant wave usually caused by an earthquake beneath the ocean floor.

Weathering

The chemical and physical processes that break down rock at Earth's surface.

Erosion

The process by which wind, water, ice, or gravity transports soil and sediment from one location to another

Soil horizon

The layer of soil that differs in color and texture from the layers above or below it.

Porosity

the volume of open spaces in rock or soil

Soil triangle

a graphic explanation of the proportions of sand, silt, and clay in soil

Humus

Rich, dark organic material formed by decay of vegetable matter, essential to soil's fertility

Leaching

the transportation of dissolved molecules through the soil via groundwater

Infiltration

Flow of water from the land surface into the subsurface.

Desertification

Degradation of land, especially in semiarid areas, primarily because of human actions like excessive crop planting, animal grazing, and tree cutting.

Salinization

A process in which mineral salts accumulate in the soil, killing plants; occurs when soils in dry climates are irrigated profusely

Waterlogging

A form of soil degradation that occurs when soil remains under water for prolonged periods.

Terracing

the creation of flat areas on mountain slopes for the purpose of farming

Contour farming

Plowing and planting across the changing slope of land, rather than in straight lines, to help retain water and reduce soil erosion.

Strip cropping

cultivation in which different crops are sown in alternate strips to prevent soil erosion.

Cover crops

crops planted to hold soil in place between the times that main food crops are growing

Ground cover

low-growing, spreading plants that help to stop weeds from growing.

No-till

refers to when farmers plant seeds without using a plow to turn the soil.

Compost

Partially decomposed organic plant and animal matter used as a soil conditioner or fertilizer.

Green manure

Freshly cut or still-growing green vegetation that is plowed into the soil to increase the organic matter and humus available to support crop growth.

Crop rotation

The practice of rotating use of different fields from crop to crop each year, to avoid exhausting the soil.

Troposphere

The lowest layer of Earth's atmosphere

Stratosphere

The second-lowest layer of Earth's atmosphere.

Coriolis effect

Causes moving air and water to turn left in the southern hemisphere and turn right in the northern hemisphere due to Earth's hemisphere.

Prevailing winds

Global winds that blow constantly from the same direction

Hadley cell

Convection Currents that cycle between the equator, 30 degrees North and South.

Watershed

An ecosystem where all water runoff drains into a single body of water

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

Microclimates

environmental conditions within a small area that differs significantly from the climate of the surrounding area

El Nino

an irregularly occurring and complex series of climatic changes affecting the equatorial Pacific region and beyond every few years, characterized by the appearance of unusually warm, nutrient-poor water off northern Peru and Ecuador, typically in late December.

La Nina

A climate event in the eastern Pacific Ocean in which surface waters are colder than normal.

Gyre

a circular motion of water in each of the major ocean basins

Upwelling

The movement of deep, cold, and nutrient-rich water to the surface often caused by winds.

Ocean conveyor belt

a constantly moving system of deep-ocean circulation driven by temperature and salinity

Weather

The condition of Earth's atmosphere at a particular time and place.

climate

the weather conditions prevailing in an area in general or over a long period.

Windward

The side of a mountain range that faces the oncoming wind.

Leeward

The side of a mountain range that faces away from the oncoming wind.