GEOG1710 1st Edition Lecture 20 Outline of Previous Lecture Outline of Current Lecture I II III IV V Glacial Landscapes Glaciers Move Glacier Formation Glacial Flow Glacial Erosion Current Lecture Glacial Landscapes Influence Global Climate o High albedo radiation budget o Ocean salinity conveyor belt Good indicators of Current Climate o Glaciers continue to get smaller because of higher temperatures Long term storage of freshwater o Only a small percentage of water on Earth is fresh water Used to study past climates o Serve as climate proxies tells us about past comates principle of super position tells us that ice goes from young to old Glaciers Move We find glaciers o On all continents except for Australia o 96 of ice on Earth is on Greenland and Antarctica o High latitudes and high altitudes Glaciers are like a river of ice o Large asses of ice flowing and sliding downslope or down a valley as a result of the pull of gravity Two Types of Glaciers o Alpine mountainous regions Rockies Flow downslope under the force of gravity These notes represent a detailed interpretation of the professor s lecture GradeBuddy is best used as a supplement to your own notes not as a substitute Cirque valley piedmont o Continental occurs at high latitudes Flow radially outward from center Glacier Formation Similar to how sediment turns into sedimentary and then into metamorphic rock Snow to firn to ice Requires two climatic conditions precipitation and freezing temps o Accumulation ablation o Accumulation addition of ice o Ablation mostly melting loss of ice Glacial Flow Plastic deformation increase in accumulation and pressure of ice causes ice to become plastic and to flow Plastic means something can be shaped or molded A solid item can be plastic like aluminum or play doh Basal sliding melt water at base of glacier reduces friction and pressure Glaciers slide down hill Flow causes stress o Tension stress o Compression stress o Both stresses causes fractures also known as crevasse Can flow up to 10 km a year Speed of flow depends on temp slope and ice thickness Movement of a glacier o Evaporation liquid to gas o Sublimation solid to vapor o Calving chunks of ice breaking off at edge of glacier Factors that affect equilibrium o Latitude elevation snowfall amount the way the slope is facing and wind o Equilibrium line Glacial Erosion Shape landscape erosion transportation and deposition Plucking ice freezes onto rock and sediment and incorporates matter onto flow Abrasion matter that is picked up will continue to scour the land as it flows with the ice Erosional Landforms o Cirque steep sided hollow at the head of a valley formed by
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