Earth Science Vocab

aquifer

permeable underground layer through which groundwater flows relatively easily

infiltration

the process by which water on the ground surface enters the soil

permeability

The ability of a rock or sediment to let fluids pass through its open spaces, or pores.

porosity

The percentage of the total volume of a rock or sediment that consists of open spaces.

water table

The upper level of the saturated zone of groundwater

zone of saturation

The depth below earth's surface where all the pores of a material are completely filled with groundwater.

cave

a large underground chamber, typically of natural origin, in a hillside or cliff. Usually is formed when ground water dissolves limestone

karst topography

A type of landscape in rainy regions where there is limestone near the surface, characterized by caverns, sinkholes, and valleys

sinkhole

a circular depression formed when the roof of a cave collapses

stalagmite

Mound-shaped drip stone deposit of calcium carbonate that forms on a cave's floor beneath a stalactite

stalactite

cone-shaped or cylindrical dripstone deposit of calcium carbonate that hangs like an icicle from a cave's ceiling

travertine

A type of limestone found in dripstone formations

artesian well

Fountain of water that spurts above the land surface when a well taps a deep, confined aquifer containing water under pressure

drawdown

Difference between the water level in a pumped well and the original water-table level

geyser

explosive hot spring that erupts regularly

hot spring

thermal spring with temperatures higher than that of the human body

recharge

Process by which water from precipitation and runoff is added to the zone of saturation

spring

natural discharge of groundwater at Earth's surface where an aquifer and an aquiclude come in contact

well

Deep hole drilled or dug into the ground to reach a reservoir of groundwater

bed load

Describes sediments that are too heavy or large to be kept in suspension or solution and are pushed or rolled along the bottom of a streambed.

discharge

measure of a volume of stream water that flows over a specific location in a particular amount of time

divide

elevated land that divides one watershed from another

floodplain

Broad, flat, fertile area extending out from a stream's bank that is covered with water during floods.

runoff

water that flows over the ground surface rather than soaking into the ground

watershed

land area drained by a stream system

delta

Triangular deposit, usually made up of silt and clay particles, that forms where a stream enters a large body of water.

meander

curve or bend in a stream formed when a stream's slope decreases, water builds up in the stream channel, and moving water erodes away the sides of the stream bed.

stream channel

Narrow pathway carved into sediment or rock by the movement of surface water

eutrophication

Process by which lakes become rich in nutrients from the surrounding watershed, resulting in a change in the kinds of organisms in the lake.

lake

natural or human-made body of water that can form when a depression on land fills with water

avalanche

landslide that occurs in a mountainous area when snow falls on an icy crust, becomes heavy, slips off, and slides swiftly down a mountainside

creep

slow, steady downhill movement of loose weathered Earth materials, especially soils, causing objects on a slope to tilt

landslide

rapid downslope movement of a mass of loose soil, rock, or debris that has separated from the bedrock; can be triggered by an earthquake

mass movement

downslope movement of earth's materials due to gravity that can occur suddenly or very slowly, depending on the weight of the material, its resistance to sliding, and whether a trigger, such as an earthquake, is involved.

mudflow

rapidly flowing, often destructive mixture of mud and water that may be triggered by an earthquake, intense rainstorm, or volcanic eruption

slump

mass movement that occurs when Earth materials in a landslide rotate and slide along a curved surface, leaving a crescent-shaped scar on a slope

abrasion

process of erosion in which wing-blown or waterborne particles, such as sand, scrape against rock surfaces or other materials, and wear them away.

deflation

Lowering of land surface caused by wind erosion of loose surface particles, often leaving coarse sediments behind.

dune

pile of wind-blown sand that develops over time, whose shape depends on sand availability, wind velocity and direction, and amount of vegetation present

loess

thick, wind-blown sand that develops over time, whose shape depends on sand availability, wind velocity and direction, and the amount of vegetation present.

ventifact

rock shaped by wind-blown sediments

cirque

deep depression scooped out by a valley glacier

continental glacier

A glacier that covers much of a continent or large island

drumlin

Elongated landform that results when a glacier moves over an older moraine

esker

long, winding ridge of layered sediments deposited by streams that flow beneath a melting glacier

glacier

Large, moving mass of ice that forms near Earth's poles and in mountainous regions at high elevations.

moraine

ridge of mixed debris deposited by a melting glacier

outwash plain

area at the leading edge of a glacier, where outwash is deposited by meltwater streams

valley glacier

Glacier that forms in a valley in a mountainous area and widens V-shaped stream valleys into U-shaped glacial valleys as it moves downslope.