GEOG 205: Assignment 1 Aynsley Merk (260269151) Question 10 The eustatic sea level curve shows a steady increase in sea level from 14 ka BP until 500 a BP. However, because the gradient is much steeper between 14-10 ka BP this indicates a faster rate of change (increase). After this period the gradient (rate of sea level rise) decreases virtually plateauing after 5 ka BP. Portland, Maine (USA) Prior to 13 ka BP Portland, Maine was covered with the Laurentide Ice Sheet. When the ice retreated sea levels were rising rapidly, shown by both the steep downwards gradient of the Portland curve and the steep upwards gradient of the Eustatic curve. This trend continues until 10 ka BP when Portland was 65 metres below modern sea level. Although sea levels continue to rise Portland does not ‘sink’ any further, instead it ‘rises’. This change in gradient (from downwards to upwards) indicates isostatic rebound. The land is ‘bouncing back’ after being depressed by the ice sheet. Between 8.4 ka BP and 5 ka BP
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This essay was uploaded on 04/18/2008 for the course GEOG 205 taught by Professor Chmera during the Spring '08 term at McGill.