Vocab for Dynamic Planet

Question Answer
Valley Glacier a mountain glacier whose flow is confined by valley walls.
Calving process by which ice breaks off a glacier's terminus; usually the term is reserved for tidewater glaciers or glaciers that end in lakes, but it can refer to ice that falls from hanging glaciers
Terminus the lowest end of a glacier, also called the glacier toe or glacier snout.
Ablation (1) combined processes which remove snow or ice from the surface of a glacier or from a snow-field; also used to express the quantity lost by these processes (2) reduction of the water equivalent of a snow cover
Ablation Area the area of a glacier where more glacier mass is lost than gained.
Ablation Hollows depressions in the snow surface caused by the sun or warm, gusty wind.
Ablation Moraine mound or layer of moraine in the ablation zone of a glacier; the rock has been plucked from the mountainside by the moving glacier and is melting out on the ice surface
Ablation Season period during which glaciers lose more mass than they gain; usually coincides with summer.
Ablation Zone area or zone of a glacier where snow and ice ablation exceed accumulation.
Absolute Difference the difference, taken without regard to sign, between the values of two variables
Absolute Error the difference between the measured or inferred value of a quantity and its actual value.
Absolute Humidity (1) the ratio of the mass of water vapor to the volume occupied by a mixture of water vapor and dry air (2) mass of water contained in a unit volume of moist air.
Accretion growth of a cloud or precipitation particle by the collision and union of a frozen particle (ice crystal or snowflake) with a super-cooled liquid droplet which freezes on impact.
Acid Precipitation Rain or Snow containing acid substances
Active Air-Cooled Thermal Pile a Foundation Pile on which a cold air refrigeration system has been installed to remove heat from the ground.
Foundation Pile structure used when the soil near the ground surface is not strong and the weight of the building must be carried by deeper soil layers.
Firn rounded, well-bonded snow that is older than one year; firn has a density greater than 550 kilograms per cubic-meter (35 pounds per cubic-foot); called neve during the first year.
Basal Slip/ Basal Sliding the sliding of a glacier over bedrock.
Crevasse open fissure in the glacier surface.
Glacier a mass of ice that originates on land, usually having an area larger than one tenth of a square kilometer; many believe that a glacier must show some type of movement; others believe that a glacier can show evidence of past or present movement.

Retreat when a mountain glacier's terminus doesn't extend as far downvalley as it previously did; occurs when ablation surpasses accumulation.
Accumulation all processes by which snow or ice are added to a glacier, which is slowly transformed into ice; other accumulation processes can include avalanches, wind-deposited snow, and the freezing of rain within the snow pack.
Esker a sinuous ridge of sedimentary material (typically gravel or sand) deposited by streams that cut channels under or through the glacier ice.
Drumlin remnant elongated hills formed by historical glacial action; it is not clear exactly how they are formed and why they form only in some glaciated regions.
Alpine Glacier a glacier that is confined by surrounding mountain terrain; also called a mountain glacier.
Glacial Advance when a mountain glacier's terminus extends farther downvalley than before; glacial advance occurs when a glacier flows downvalley faster than the rate of ablation at its terminus.
Surging Glacier a glacier that experiences a dramatic increase in flow rate, 10 to 100 times faster than its normal rate; usually surge events last less than one year and occur periodically, between 15 and 100 years.
Sublimation the transition of a substance from the solid phase directly to the vapor phase, or vice versa, without passing through an intermediate liquid phase.
Evaporation the physical process by which a liquid or solid substance is transformed to the gaseous state
Mass Balance the difference between accumulation and ablation on a glacier; usually calculated on an annual basis.
Snowfall the depth of new snow that has accumulated since the previous day or since the previous observation.
Snowmelt melting of the snowcover, and also the period during which melting of the snow cover occurs at the end of the winter.
Moraine a mound, ridge, or other distinct accumulation of glacial till.
Glacial Till accumulations of unsorted, unstratified mixtures of clay, silt, sand, gravel, and boulders; the usual composition of a moraine.
Ice Sheet enormous continental masses of glacial ice and snow expanding over 50,000 square kilometers. The ice sheet on Antarctica is over 4200 meters thick in some areas, covering nearly all of the land features except the Transantarctic Mountains
Ice Shelves Occur when ice sheets extend over the sea, and float on the water. In thickness they range from a few hundred meters to over 1000 meters
Ice Caps Miniature ice sheets covering less than 50,000 square kilometers. They form primarily in polar and sub-polar regions that are relatively flat and high in elevation
Ice Streams/Outlet Glaciers Channelized glaciers that flow more rapidly than the surrounding body of ice
Icefields Similar to ice caps, except that their flow is influenced by the underlying topography, and they are typically smaller than ice caps
Piedmont Glacier Occur when steep valley glaciers spill into relatively flat plains, where they spread out into bulb-like lobes. The Malaspina Glacier in Alaska is one of the most famous examples of this type of glacier. It is the biggest in the world.
Cirque Glaciers named for the bowl-like hollows they occupy, which are called cirques. Typically, they are found high on mountainsides and tend to be wide rather than long.
Cirque Bowl Like Hollows carved out by Cirque Glaciers.
Hanging Glaciers Also called ice aprons, these glaciers cling to steep mountainsides. Like cirque glaciers, they are wider than they are long. They cause avalanches and many are located in the Alps.
Tidewater Glaciers These are valley glaciers that flow far enough to reach out into the sea. They are responsible for calving many icebergs.
Fjords Long, narrow coastal valleys that were originally carved out by glaciers. Steep sides and rounded bottoms give them a trough-like appearance.
Aretes jagged, narrow ridges created where the back walls of two cirque glaciers meet, eroding the ridge on both sides.
Horns such as the famous Matterhorn in Switzerland, are created when several cirque glaciers erode a mountain until all that is left is a steep, pointed peak with sharp, ridge-like aretes leading up to the top
Kettle Lakes form when a piece of glacier ice breaks off and becomes buried by glacial till or moraine deposits. Over time the ice melts, leaving a small depression in the land, filled with water.
Rock Glaciers Rocks coat the surface of this type of glacier and iceflow is evident by the arrangement of rock.
Ice Caves Caves Melted into the glacier
Ogives alternating dark and light bands of ice occurring as narrow wave crests and wave valleys on glacier surfaces. They only occur below icefalls, but not all icefalls have these below them.
Icefall A portion of some glaciers characterized by rapid flow and a chaotic crevassed surface. May cause km movement/yr.
Chatter Marks one or, more commonly, a series of marks made by vibratory chipping of a bedrock surface by rock fragments carried in the base of a glacier. Marks tend to be crescent-shaped and oriented at right angles to the direction of ice movement.
Glacial Trough A deep U-shaped valley with steep sides that leads down from a cirque and was excavated by a glacier
Erratic Rocks deposited by Glaciers where they aren't supposed to be.
Glacial Striations scratches or gouges cut into bedrock by glacial abrasion
Abrasion the mechanical scraping of a rock surface by friction between rocks and moving particles during their transport by glaciers
(The Milankovitch Theory) The explanation for climate changes (believed to be variations in the earth's orbit around the sun)
Perihelion Closest approach of the earth to the sun
Fraction of Freshwater Locked up in Glaciers etc. 2/3
Paternoster Lake a series of glacial lakes connected by a single stream or a braided stream system

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