Chapter Sixteen Groundwater Types of Glaciers A large body of ice that flows downslope or spreads radially due to gravity. Glaciers cover ~ 10% of land surface today. Types of Glaciers- based on local topography Alpine – confined by surrounding bedrock highlands (small) Cirque- create and occupy semicircular basins on Mountain sides Valley- flow in valleys formally occupied by rivers Ice caps- found on Mountain tops Piedmont- found at foot of mountains Continental Ice Sheets- massive ice that covers much of a continent Climap Relationship between glaciers and latitude Formation of glacial ice from snow Elevation and slop steepness are two factors influencing glacier formation Types of glaciers Anatomy of a Glacier Mechanics of glacial flow Glacial abrasion and quarrying combine to shape a roche moutonnee. Deposition of glacial till Glacial advance and retreat and the deposition of moraines Geology at a Glance Medial moraines Geology at a glance Effect of the North American icesheets on the Greatlake glaciers The creation and draining of Glacial Lake Missoula Formation of terraces from crustal rebound Terraces rebound – contd. Formation of terraces from robound Features of periglacial environment Beringia detail Pollen concentration vs depth Coiling pattern vs climate Oxygen isotope composition Climate change during Quaternary Milankovitch’s theory Origin of North Atlantic deepwater Global climatic changes during Cenozoic Effect of the North American ice sheet Human activity contributes to global warming If all the ices were melt tomorrow – W hat happens?? Summary Time needed for fresh snow to become glacial ice Classification of glaciers Velocity of glacial flow Glacial drift Glacial till & outwash Moraine, loess, permafrost Marine record of ancient climatic change – foram Ice core studies – atmos carbon dioxide, volcanic eruptions, wind intensity, etc. Albedo Tillite Little ice ages Changes in global temperature Changes in salinity-driven current system