| A | B |
|---|
| groundwater | the fresh water found beneath Earth's surface within cracks and among particles of rock and soil |
| water cycle | the continuous movement of water in all its forms among Earth's oceans. atmosphere, and land |
| transpiration | the loss of water through the leaves of plants |
| glacier | a large mass of ice and snow moving on land |
| runoff | water that flows over Earth's surface |
| tributaries | a smaller stream that flows into a major river |
| watershed | the area of land that contributes water to a river system |
| saturated zone | the region beneath Earth's surface where pore spaces are entirely filed with groundwater |
| water table | the top surface of the saturated zone |
| permeeable | a desricption of a material that water can easily pass through |
| aquifer | a permeable rock layer that is saturated with water |
| impermeable | a description of a material through which water cannot easily pass |
| erosion | the process that wears down and carries away rock and soil |
| weathering | the process by which rocks are chemically altered or physically broken into fragments |
| mechanical weathering | the process of physically breaking rock into smaller fragments |
| abrasion | a form of mechanical weathering that occurs when rocks scrape or grind against one another |
| chemical weathering | the process in which rock is broken down by chemical reactions |
| mass movement | the downward movement of rock and soil due to gravity, including landslides, mudflows, creep, and slumping |
| deposition | the placement of sediment that has been transported from another location |
| saltation | movement of particles such as sand carried by water or wind in a series of little leaps |
| flood plain | the flat area along a stream that is covered only during floods |
| meander | a loop-likebend in a river formed when slow-moving water deposits sediment on the inside curve of the river |
| oxbow lake | a lake formed when a river forms a new path by cutting og a meander loop from the rest of the river |
| alluvial fan | a fan-shaped deposit of sediment, on land formed as a stream flows out of the mountains and onto a plain |
| delta | a mass of sediment deposited at the mouth of a river where the river eneters a large body of water |
| stalactite | an icicle-like formation on a cavern ceiling that forms when water drips from the cavern ceiling |
| stalagmite | a pillar of minerals in a cavern formed when water drips down to the cavern floor |
| sinkhole | a hole that results when erosion weakens a layer of limestone, causing portions of the ground to suddenly colapse |
| continental glacier | a thick sheet of ice that covers a large areaof a continent or large island |
| valley glacier | a long, narrow mass of moving ice and snow that usualy begins near a mountain peak and winds down from the mountains through a valley formed originally by a stream |
| plucking | a process in which glacial ice widens cracks in bedrock beneath a glacier, which carries away the loosened pieces of rock |
| cirques | a large bowl-shaped valey carved out of a mountainside by a glacier |
| till | glacial sediment left behind when a glacier melts |
| moraines | mounds of till formed at the downhill end of a glacier and along its sides |
| deflation | the process that occurs when wind picks up and removes surface material |
| dunes | deposits formed from windblown sand |
| loess | a deposit formed from windblown dust |
| salinity | the proportion of dissolved salts in water |
| continental shelf | the gently sloping plain that forms an apron of shallow water along the edges of most continents |
| surface current | a large stream on ocean water that moves continuously in about the same path |
| density currents | currents caused by differences in the density of ocean water |
| upwelling | the movement of water from the deep ocean to te ocean's surface |
| hydraulic action | the process by which ocean waves erode rock |
| longshore drift | the process by which ocean waves move sand along a shore |
| fossils | the preserved remains or traces of a living organism |
| relative age | the age of a rock compared to the ages of other rocks above or below it in a sequence of rock layers |
| law of superposition | law stating that in rock layers that are undisturbed, younger rocks lie above older rocks, and the oldest rocks are at the bottom |
| extinct | a description of a type of organism that is no longer found living on Earth |
| index fossils | a fossil of a species that is easily identified,occured over a large area, and lived for a well-defined period of time |
| absolute age | the time that has passed sice a rock formed |
| era | a major stage in Earth's geological history |
| periods | a unit of geoligical time into which geologists divide eras |
| mass extinction | a boundary between geologic eras when many different kinds or organisms became extinct within a relatively short time |
