GLY 101 1st Edition Lecture 26Outline of Last Lecture I. Mass WastingOutline of Current Lecture II. GlaciersIII. Glacial ErosionCurrent LectureI. Glaciers-a glacier is a thick ice mass that forms over hundreds or thousands of years. -ice shelves are large and relatively flat masses of glacial ice extend seaward from the coast but reman attached to the land alone one or more sides.-covering some uplands and plateaus are masses of glacial ice called ice caps-ice caps and ice sheets feed into outlet glaciers-outlet glaciers are tongues of ice that flow downward valleys and extend outward from larger ice masses-piedmont glaciers occupy broad lowlands at the bases of steep mountains and form when one or more alpine glaciers emerge from the confining walls of mountains valleys.-the elevation above which the snow remains throughout the year is called the snowline-the movement of glacial ice is referred to as the flow-a second mechanism of glacial movement consists of an entire ice mass slipping along the ground, basal slip-melt water acts as a lubricant and helps move the ice over rocksThese 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.-snow accumulation and ice formation occur in the zone of accumulation-when the glacier moves over irregular terrain, the zone of fracture is subjected to tension, resulting cracks called crevasses.-periods of extremely rapid movements are called surges -below the snowline is the zone of wastage-glaciers waste as large pieces of ice break off the front of a glacier, in a process called calving.-glacial budget is the balance or lack of balance between accumulation at the upper end of the glacier and loss at the lower end-this loss is known as ablationII. Glacial Erosion-Glaciers erode the land in two ways: plucking and abrasion.-plucking occurs when meltwater penetrates the cracks and joints of bedrock beneath a glacier and freezes.-abrasion is when ice and rock fragments slide over bedrock the result is the bedrock beneath it becomes smooth and polished-Landforms that are created by glacial erosion are arete, tarn, horn, cirques, glacial
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