Dynamic Planet Flashcards
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.
Accumulation Area
Area of a glacier where more mass is gained than lost.
Accumulation Season
Period during which a glacier gains more mass than it loses usually coincides with winter.
Accumulation Zone
Area of a glacier where more mass is gained than lost.
Advance
When a mountain glacier’s terminus extends farther down valley than before; glacial advance occurs when a glacier flows down valley faster than the rate of ablation at its terminus.
Alpine Glacier
A glacier that is confined by surrounding mountain terrain; also called a mountain glacier.
Arête
Sharp, narrow ridge formed as a result of glacial erosion from both sides.
Band Ogives
Alternate bands of light and dark on a glacier; usually found below steep narrow icefalls and thought to be the result of different flow and ablation rates between summer and winter.
Basal Sliding
The sliding of a glacier over bedrock.
Bergschrund
Crevasse that separates flowing ice from stagnant ice at the head of a glacier.
Branched-Valley Glacier
Glacier that has one or more tributary glaciers that flow into it; distinguished from a simple valley glacier that has only a single tributary glacier.
Catchment Glacier
A semi permanent mass of firn formed by drifted snow behind obstructions or in the ground; also called a snowdrift glacier or a drift glacier.
Chattermarks
Striations or marks left on the surface of exposed bedrock caused by the advance and retreat of glacier ice.
Cirque
Bowl shaped or amphitheater usually sculpted out of the mountain terrain by a cirque glacier. Also called a corrie or cwm.
Cirque Glacier
Glacier that resides in basins or amphitheaters near ridge crests; most cirque glaciers have a characteristic circular shape, with their width as wide or wider than their length.
Cold Glacier
Glacier in which most of the ice is below the pressure melting point; nonetheless the glacier’s surface may be susceptible to melt due to incoming solar radiation.
Compression Flow
Flow that occurs when glacier motion is decelerating down-slope.
Constructive Metamorphism
Snow metamorphism that adds molecules to sharpen the corners and edges of an ice crystal.
Crevasse
Open fissure in the glacier surface.
Crevasse Hoar
A kind of hoarfrost; ice crystals that develop by sublimation in glacial crevasses and in other cavities with cooled space and calm, still conditions.
Dead Ice
Any part of a glacier which has ceased to flow; dead ice is usually covered with moraine.
Dirt Cone
A cone-shaped formation of ice that is covered by dirt; caused by a differential pattern of ablation between the dirt-covered surface and bare ice.
Drain Channel
Preferred path for meltwater to flow from the surface through a snow cover.
Drift Glacier
A semi-permanent mass of firn formed by drifted snow behind obstructions or in the ground; also called a catchment glacier or a snowdrift glacier.
Drumlin
Remnant elongated hills formed by historical glacial action; it is not clear exactly how they are formed.
Dump Moraine
A mound or layer of moraine formed along the edge of a glacier by rocks that fall off the ice; sometimes called a ground moraine.
End Moraine
An arch-shaped ridge of moraine found near the end of a glacier.
Equilibrium Zone
Zone of a glacier in which the amount of precipitation that falls is equal to the amount that melts the following summer.
Esker
A sinuous ridge of sedimentary material (typically gravel or sand) deposited by streams that cut channels under or through the glacier ice.
Extending flow
When glacier motion is accelerating down-slope.
False ogives
Bands of light and dark on a glacier that were formed by rock avalanching.
Fjord
Glacial troughs that fill with seawater.
Foliation
Layering in glacier ice that has distinctive crystal sizes and/or bubbles; usually caused by stress and deformation.
Forbes bands
Alternate bands of light and dark on a glacier; usually found below steep narrow icefalls.
Forel stripes
Shallow, parallel grooves on the face of a large melting ice crystal.
Geyser
Fountain that develops when water from a conduit is forced up to the surface of a glacier; also called a negative mill.
Glacial advance
When a mountain glacier’s terminus extends farther downvalley than before; occurs when a glacier flows downvalley faster than the rate of ablation at its terminus.
Glacial Erratic
A boulder swept from its place of origin by glacier advance or retreat and deposited elsewhere as the glacier melted.
Glacial grooves
Grooves or gouges cut into the bedrock by gravel and rocks carried by glacial ice and meltwater; also called glacial striations.
Glacial retreat
When the position of a mountain glacier’s terminus is farther upvalley than before; occurs when a glacier ablates more material at its terminus than it transports into that region.
Glacial striations
Grooves or gouges cut into the bedrock by gravel and rocks carried by glacial ice and meltwater; also called glacial grooves.
Glacial till
Accumulations of unsorted, unstratified mixtures of clay, silt, sand, gravel, and boulders; the usual composition of a moraine.
Glacial trough
A large u-shaped valley formed from a v-shaped valley by glacial erosion.
Glaciated
Land covered in the past by any form of glacier is said to be glaciated.
Glacier
A mass of ice that originates on land, usually having an area larger than one-tenth of a square kilometer.
Glacier cave
A cave of ice, usually underneath a glacier and formed by meltwater.
Glacier fire
A phenomenon in which strong reflection of the sun on an icy surface causes a glacier to look like it is on fire.
Glacier flood
A sudden outburst of water released by a glacier.
Glacier flour
A fine powder of silt- and clay-sized particles that a glacier creates as its rock-laden ice scrapes over bedrock.
Glacier ice
Well-bonded ice crystals compacted from snow with a bulk density greater than 860 kilograms per cubic meter.
Glacier mill
A nearly vertical channel in ice that is formed by flowing water.
Glacier pothole
Potholes formed at the bottom of glaciers through erosion caused by sand and gravel in melt-water.
Glacier remainie
A glacier that is reconstructed or reconstituted out of other glacier material.
Glacier snout
The lowest end of a glacier; also called glacier terminus or toe.
Glacier sole
The bottom of the ice of a glacier.
Glacier table
A rock that resides on a pedestal of ice; formed by differential ablation between the rock-covered ice and surrounding bare ice.
Glacier terminus
The lowest end of a glacier; also called glacier snout or toe.
Glacier toe
The lowest end of a glacier; also called glacier snout or terminus.
Glacier trough
U-shaped valleys transformed from v-shaped stream valleys due to erosion caused by passing glaciers.
Glacieret
A very small glacier.
Glacierized
Land overlaid at present by a glacier is said to be covered.
Ground moraine
Continuous layer of till near the edge or underneath a steadily retreating glacier.
Hanging glacier
A glacier that terminates at or near the top of a cliff.
Hanging valley
A valley formed by a small glacier that has a valley bottom relatively higher than nearby valleys formed by larger glaciers.
Headwall
A steep cliff, usually the uppermost part of a cirque.
Horn
A peak or pinnacle thinned and eroded by three or more glacial cirques.
Ice apron
A mass of ice adhering to a mountainside.
Ice cap
A dome-shaped mass of glacier ice that spreads out in all directions; usually larger than an icefield but less than 50,000 square kilometers.
Ice cave
A cave of ice, usually underneath a glacier and formed by meltwater.
Ice covered
Land overlaid at present by a glacier is said to be covered.
Ice divide
The boundary separating opposing flow directions of ice on a glacier or ice sheet.
Ice quake
A shaking of ice caused by crevasse formation or jerky motion.
Ice sheet
A dome-shaped mass of glacier ice that covers surrounding terrain and is greater than 50,000 square kilometers.
Ice stream
A current of ice in an ice sheet or ice cap that flows faster than the surrounding ice.
Ice-cemented glacier
A rock glacier that has interstitial ice a meter or so below the surface.
Ice-cored glacier
A rock glacier that has a buried core of ice.
Icefall
Part of a glacier with rapid flow and a chaotic crevassed surface; occurs where the glacier bed steepens or narrows.
Ice field
A mass of glacier ice; similar to an ice cap, and usually smaller and lacking a dome-like shape.
Jokulhlaup
A large outburst flood that usually occurs when a glacially dammed lake drains catastrophically.
Lateral moraine
A ridge-shaped moraine deposited at the side of a glacier and composed of material eroded from the valley walls.
Marginal crevasse
A crevasse near the side of a glacier formed as the glacier moves past stationary valley walls.
Medial moraine
A ridge-shaped moraine in the middle of a glacier originating from a rock outcrop, nunatak, or the converging lateral moraines of two or more ice streams.
Meltwater conduit
A channel within, underneath, on top of, or near the side of a glacier that drains meltwater out of the glacier.
Moraine
A mound, ridge, or other distinct accumulation of glacial till.
Moraine shoal
Glacial moraine that has formed a shallow place in water.
Moulin
A nearly vertical channel in ice that is formed by flowing water.
Mountain glacier
A glacier that is confined by surrounding mountain terrain; also called an alpine glacier.
Negative mill
A geyser; a fountain that develops when water from a conduit is forced up to the surface of a glacier.
Niche glacier
Very small glacier that occupies gullies and hollows on north-facing slopes; may develop into cirque glacier if conditions are favorable.
Nunatak
A rocky crag or small mountain projecting from and surrounded by a glacier or ice sheet.
Ogives
Alternate bands of light and dark ice seen on a glacier surface.
Outburst flood
Any catastrophic flooding from a glacier; may originate from trapped water in cavities inside a glacier.
Outlet glacier
A valley glacier which drains an inland ice sheet or ice cap and flows through a gap in peripheral mountains.
Paternoster lakes
A series of tarns connected by a single stream or a braided stream system.
Piedmont glacier
Large ice lobe spread out over surrounding terrain, associated with the terminus of a large mountain valley glacier.
Polar glacier
A glacier entirely below freezing, except possibly for a thin layer of melt near the surface during summer.
Pothole
A nearly vertical channel in ice that is formed by flowing water.
Push moraine
Moraine built out ahead of an advancing glacier.
Randkluft
A fissure that separates a moving glacier from its headwall rock.
Reconstituted glacier
A glacier that is reconstructed or reconstituted out of other glacier material.
Reconstructed glacier
A glacier that is reconstructed or reconstituted out of other glacier material.
Regelation
Motion of an object through ice by melting and freezing that is caused by pressure differences.
Regenerated glacier
A glacier that is reconstructed or reconstituted out of other glacier material.
Retreat
When a mountain glacier’s terminus doesn’t extend as far downvalley as it previously did; occurs when ablation surpasses accumulation.
Retreating glacier
A glacier whose terminus is farther upvalley than before.
What is the process that allows a glacier to slide past small obstacles on its bed?
The melting and freezing of an object through ice caused by pressure differences.
What is a regenerated glacier?
A glacier reconstructed or reconstituted out of other glacier material, usually formed by seracs falling from a hanging glacier then re-adhering.
Also called reconstituted or reconstructed glacier, or glacier remainie.
What does retreat mean in glaciology?
When a mountain glacier’s terminus doesn’t extend as far downvalley as it previously did, occurring when ablation surpasses accumulation.
What is a retreating glacier?
A glacier whose terminus is increasingly retreating upvalley compared to its previous position due to a higher level of ablation compared to accumulation.
What is rock flour?
A fine powder of silt- and clay-sized particles created as a glacier scrapes over bedrock, usually flushed out in meltwater streams, causing water to look powdery gray.
Lakes and oceans that fill with glacier flour may develop a banded appearance.
What is a rock glacier?
A glacier that looks like a mountain glacier and has active flow, usually including a poorly sorted mess of rocks and fine material.
What are sedimentary ogives?
Alternating bands of light and dark at the firn limit of a glacier, with light bands being younger and darker as they progress down-glacier.
What is a serac?
An isolated block of ice formed where the glacier surface is fractured.
What is sintering?
The bonding together of ice crystals.
What is a snowdrift glacier?
A semipermanent mass of firn formed by drifted snow behind obstructions or in the ground.
Also called a catchment glacier or a drift glacier.
What is a splay crevasse?
A crevasse pattern that forms where ice slowly spreads out sideways, commonly found near a glacier terminus.
What is a sub polar glacier?
A glacier whose temperature regime is between polar and temperate, usually predominantly below freezing but could experience extensive summer melt.
What is a surging glacier?
A glacier that experiences a dramatic increase in flow rate, 10 to 100 times faster than its normal rate, usually lasting less than one year and occurring periodically, between 15 and 100 years.
What is a tarn?
A small mountain lake or pool.
What is a terminus?
The lowest end of a glacier, also called the glacier toe or glacier snout.
What is a Thomson crystal?
A large ice crystal found in deep, stagnant water-filled cavities of a glacier.
What is a tidewater glacier?
A mountain glacier that terminates in the ocean.
What is a tongue in glaciology?
A projection of the ice edge up to several km in length caused by wind and current, usually forming when a valley glacier moves very quickly into a lake or ocean.
What is a tributary glacier?
A small glacier that flows into a larger glacier.
What is a valley glacier?
A mountain glacier whose flow is confined by valley walls.
What are wave ogives?
Ogives that show some vertical relief on a glacier, with dark bands in the hollows and light bands in the ridges, forming at the base of steep, narrow ice falls.
What is weathered ice?
Glacier ice that has been exposed to sun or warm wind so that the boundaries between ice crystals are partly disintegrated.
