ENV234H1 Lecture Notes - Lecture 4: Lake Simcoe, Holland Marsh, Tunnel Valley
10 Oct 2016
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Document Summary
During deglaciation, a tunnel valley formed by the gushing meltwater (huge quantities of water) created a tunnel off the retreating lobe. After orm was formed, lake algonquin covered much of the area to the northwest. With isostatic response, the southern end of lake simcoe tilted up and caused flooding of the tunnel valley. From 4000 years ago to present, rich organic matter accumulated. Note: marshes do not have trees, while swamps have trees. Canada"s glaciological history helps to explain today"s landscapes. There is not enough data millennials ago; no long-term data and no historical (written) records of past conditions. Reconstructions used to establish the change (environmental, climate etc. ) that occurred in the past. Able to understand the processes responsible for the observed past changes. Knowledge of changes through time is needed for the assessment of future environmental and ecological change. Global climate history from glacier sediments (till); ice cores; organism sediments.
