GEOL1403 FinalExam (last two chapters)

wavebase (or wave base)

the depth at which the orbital motion of a wave dies out

wave height

the vertical distance between the crest and the trough of a wave

wave length

the distance between two adjacent wave crests

zone of accumulation

the area where the rate of snowfall is greater than the rate of melting, resulting in an increase in snow mass

glacier

a slowly moving mass of ice formed by the accumulation and compaction of snow on mountains or near the poles

horn

a sharp peak bounded by 3 or more cirques

arêtes

sharp ridges between two U-shaped glacial valleys

moraine

accumulation of earth and stone (glacially eroded debris) carried and finally deposited by a glacier

till

sediments that have been eroded, transported, and deposited by glacial ice

glacial period

any period of time during which a large part of the Earth's surface was covered with ice; ice age

snowline

the boundary representing the lowest altitude at which snow remains partially un-melted throughout the year

zone of wastage (ablation)

the portion of a glacier where more ice melts than accumulates, resulting in a net loss of ice mass

marine terrace

a flat area often found at the base of a sea cliff or along the shoreline of a lake, bay, or ocean that was created by the weathering of the cliff

tide

the daily change (usually diurnal) in the ocean level caused by the gravitational attraction of the moon, and to a lesser extent, the sun.

tsunami

a large wave cause by a submarine seismic event (an earthquake, a volcanic eruption, or a landslide)

wave refraction

waves are bent (refracted) as one portion slows relative to another, caused by the drag on the bottom of the water body, which in turn causes a decrease in velocity

coastal erosion

erosion caused by the abrasive action of moving sand and gravel transported by wave motion

longshore (beach) drift

progressive movement of sediment along the beach in a zigzag pattern caused by waves approaching the shoreline at an oblique angle

breaker

behavior of waves when the wave base intersects the bottom of the water body causing water to swash up the shoreline and then backwash down the shoreline

valley glaciers

a glacier originating at a valley head and moving downward between the walls of a valley

coastal deposition

the deposition of material on the coast that occurs when waves lose energy and drop sediment

sea wall (seawall)

a wall or embankment erected to prevent the sea from encroaching on or eroding an area of land

groins

a low wall or sturdy timber barrier built perpendicular to the shoreline to check erosion and movement of beach material

spit

an elongated sandy deposit that extends out into open water in a bay or inlet in the direction of long-shore drift

barrier island

an offshore deposit of material that forms an island that runs parallel to the shoreline and is separated from the mainland by a lagoon

ice sheet (continental glacier)

a large sheet of ice and snow that covers an entire region and spreads out under its own weight

cirque

a bowl-shaped depression at the head of a valley or on a mountainside formed by glacial erosion

calving

large pieces of ice break off into the water forming icebergs; usually caused by glacier expansion

sublimation

the process of going from a solid to a gas without going through the liquid phase

evaporation

the process of a liquid converting to a gas

melting

the process of a solid converting to a liquid

outwash plain

a plain formed of glacial sediments deposited by the outwash of melted water from underneath a glacier

crevasse

a deep crack or fracture formed in an ice sheet or glacier

basal sliding

movement of a glacier over underlying material due to meltwater acting as a lubricant

wave period

the time between passage of successive waves

shore (shoreline)

the area that extends between the lowest tide level and the highest elevation on land that is affected by storm waves

swash

the upward motion of water on a beach caused by the breaking of waves

backwash

the movement of water down the slope of a beach after the breaking of a wave

glacial striations

scratches in underlying rock caused by abrasion of sediment on the bottom of a glacier as it moves downward and/or outward from the head of the glacier

U-shaped valley

a steep-sided valley caused by glacial erosion

fjord (fiord)

long, narrow arm of the sea bordered by steep cliffs and caused when sea level rises filling the U-shaped valley caused by a glacier

Milankovitch cycle

variations in weather patterns caused by changes in the shape of Earth's orbit and its tilt relative to the vertical

rock flour

fine-grained, silt-sized mineral particles generated by abrasion of bedrock through glacial erosion

beach

eroded material that has been transported from elsewhere and deposited along a shoreline

hanging valley

a glacial valley that is cut across by a deeper valley or cliff