Porosity
The proportion of void space in a material.
Permeability
A measure if how readily fluids pass through the material.
Saturated or phreatic zone
The zone in which all the soil or rock is water-saturated.
Groundwater
The water that is in the saturated zone.
Unsaturated or vadose zone
The zone above the saturated zone in which soil and rock are partly filled with air and part water.
Soil Moisture
The water in the unsaturated zone.
Water Table
The top surface of the saturated zone where the zone is not confined by overlaying impermeable rock.
Recharge
The process of infiltration and migration or percolation by which ground water is replaced.
Discharge
Where ground water flows into a stream, escapes at the surface in a spring, or otherwise exits the aquifer.
Aquifer
A rock that holds enough water and transmits it rapidly enough to be useful as a source of water.
Aquitard
A rock that may store a considerable quantity of water, but in which water flow is slowed.
Unconfined Aquifer
When an aquifer is directly overlain by permeable rocks and soil.
Confined Aquifer
Bounded above and below by low permeable rocks (aquitards).
Artesian System
When a well is drilled into a confined aquifer, the water can rise above its level in the aquifer because of the extra hydrostatic (fluid) pressure.
Potentiometric Surface
The height to which the water's pressure would raise the water if the water was unconfined.
Hydraulic Head
The potential energy of how rapidly groundwater flows.
Cone of Depression
Circular lowering of the water table immediately around the well in an unconfined aquifer.
Salt Water Intrusion
When salt water mixes with the ground water in coastal areas.
Karst
When dissolution of rocks by subsurface water and occasional collapse of the ground surface forms this distinctive terrain.
Sinkhole
When the ground suddenly collapses as a result of dissolution of the rocks underneath the hole.
Hard Water
Water that contains substantial amounts of dissolved calcium and magnesium.
Mechanical Weathering
Also called physical weathering. The physical breakup of rocks without changes in the rocks composition.
Chemical Weathering
Involves the breakdown of minerals by chemical reaction with water, with other chemicals dissolved in water, or with gases in the air.
O Horizon
Consists wholly of organic matter, whether living or decomposed. Growing plants, decaying leaves, and so on.
A Horizon
Below the O Horizon consists of mostly intensely weathered rock material because it is the zone most exposed to surface processes.
Leaching
When water comes through the A Horizon dissolving soluble minerals and carry them away.
E Horizon
Below the A horizon, known as the zone of leaching.
B Horizon
Also known as the zone of accumulation because it collects the leached materials through E Horizon.
C Horizon
The base of the soil profile.
Pedalfer
Soils were seen as characteristic of more humid regions. The climate is wetter, there is naturally more extensive leaching of the soil.
Pedocal
The soil of a dry climate.
laterite
An extreme type of pedalfer. Forms in forms in Tropical Climates with high temperatures.
Pegmatite
The term given to unusually coarse-grained igneous intrusions.
Kimberlites
Igneous rocks that occur as pipe-like intrusive bodies that must have originated in the mantle.
Hydrothermal
Literally hot water.
Banded Iron Formation
Layered sedimentary iron ores.
Evaporite
When a body of seawater trapped in a shallow sea dries up, it deposits these minerals.
Placers
Formed from coastal currents causing sediment sorting and selective concentration of minerals.
Remote Sensing
Investigation without direct contact, as by using aerial or satellite photography, radar, and so on.
Darcy's Law
Relationship of groundwater flow rate between two points to the difference in hydraulic head between them.
Manganese Modules
Lumps up to about 10 centimeters in diameter, composed mostly of manganese materials.
Tailings
Waste materials that may end up heaped around a processing plant to weather and wash away much like spoil banks.
Fossil Fuels
Energy sources that formed from the remains of once-living organisms.
Petroleum
Liquid Hydrocarbons derived from organic matter and used as fuel.
Oil
Any of various liquid hydrocarbon compounds.
Non-Renewable
Not being replenished or formed at any significant rate on a human timescale.
Coal-Bed Methane
Treated as a hazardous nuisance, potentially explosive, and its incidental release when coal mining has contributed to rising methane concentration in the atmosphere.
Geopressurized Zones
Zones that contain large amounts of recoverable gas.
Methane Hydrates
Crystalline solids of gas and water molecules.
Anaerobic
Condition in which oxygen is nearly or completely absent since reaction with oxygen destroys the organic matter.
Gastification
When a material is converted to natural gas through processes.
Liquefaction
When a material is converted to a liquid through processes.
Kerogen
A waxy solid in the potential fuel of an oil shale.
Tar Sands
Also known as oil sands, are sedimentary rocks containing a very thick, semisolid, tar-like petroleum.
Bitumen
A tar like petroleum found in tar sands.
Fission
The splitting apart of atomic nuclei into smaller ones, with the release of energy.
Fusion
The combining of smaller nuclei into larger ones, also releasing energy.
Chain Reaction
Happens when newly released neutrons induce fission in other minerals which then releases more neutrons.
Breeder Factor
Can maximize the production of new fuel.
Core Meltdown
When the there is overheating of the core in which the fuel and core materials would deteriorate into a molten mass that might or might not melt its way out the containment building.
Decommissioned
When plants are taken out of operation, broken down, and the most radioactive parts are disposed opt properly.
Photovoltaic Cells
Also known as solar cells, direct production of electricity using sunlight.
Geothermal Energy
Heat from cooling magma heats nearby groundwater.
Geothermal Gradient
The rate of increase of temperature with increasing depth in the earth.
Hot-Dry-rock
Type that shows the potential geothermal resource.
Ocean Thermal Energy Conversion
Another clean, renewable technology that is currently in the developmental stages.
Biofuels
Fuels derived from living organisms or from organic matter.