TERMINOLOGIES RELATED TO GLACIERS

• ABLATION – all forms by which snow is lost from glacier – by evaporation & melting
  

• ABLATION AREA – area where snowfall is less than snow ablation, demarcated from accumulation by firnline
  

• ACCUMULATION AREA – area where snow accumulates
  

• ALBEDO – percentage of sun’s radiation reflected off
  

• CIRQUE – deep, steep-walled recess in mountain, glacial erosion
  

• CREVASSES – fissures in glacial ice, variable speed of ice
  

• EQUILIBRIUM LINE – demarcation between accumulation and ablation area
  

• ERRACTIC – rock of unspecified size or shape, transported by glacier
  

• FIRN – old snow recrystallized into more dense substance
  

• FIRNLINE – above firnline glacier ice, is converted from snow as air is forced out
  

• GLACIAL ADVANCE – Net Movement of Glacier terminus down valley
  

• GLACIAL DRIFT – loose & unsorted rock debris distributed by glacier & glacial meltwaters
  

• GLACIAL FLOUR – fine-grained sediments carried by glacial rivers
  

• GLACIAL RETREAT – net movement of glacier upvalley when ablation exceeds accumulaton
  

• GLACIAL TILL – an unsorted unstratified mixture of time & coarse rock debris
  

• GLACIER CAVE – steam or high heat flow
  

• GLACIER ICE – snowflakes composed by weight of overlying snowpack
  

• GLACIER MORAINE – deposition feature
  

• GLACIER SNOUT – terminus of glacier
  

• ICEFALL – analogous to waterfall
  

• JOKULHLAUP – sudden outbursts of water from glaciers
  

• LAHAR – Mudflow or debrisflow originating in river
  

• LATERAL MORAINE – Piles of loose unsorted rocks along side margins of glacier
  

• MASS BALANCE – net gain or loss of snow
  

• MEDIAL MORAINE – moraine formed by convergence of two lateral moraines
  

• NEOGLACIATION – advances made by mountain glaciers in Great Pleistocene Ice age
  

• OGIVES – Arc shaped features across glacier surface below icefall
  

• ROCHE MOUTONNEES – small asymmetric hill of glacial erosion
  

• ROCKFLOUR – Glacier Flour
  

• ROCK GLACIER – Glacier like landform
  

• SERACS – pinnacles of ice where glacier surface is torn by crevasses
  

• STRIATIONS – scratches on rock surface
  

• SUNCUP – Small Depression on snow or firn
  

• SURGE – short-lived frequently large scale increase in rate of movement of ice within a glacier
  

• TARN – lakes developed on the basis of a cirque
  

• TERMINAL MORAINES – piles of loose unconsolidated rock at glacier lowerend
  

• TERMINUS – downvalley end of glacier
  

• TILL – unsorted rock debris
  

• TRIMLINE – sharp vegetative margindemarking the upper margin of a former glaciation
  

• TUYA – volcano exploded under a glacier U-shaped valley