Earth Sciences 2281A/B Lecture 10: Glaciers and Glacial Processes
16 Apr 2017
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Document Summary
Major impact on landscape and soils in canada. Recent glaciation took place over 1. 8 million years (pleistocene), ended ~ 10000 years ago. During maximum cold phases of the pleistocene ~29% earth"s surface was covered with glacial ice. Glacial deposits/drift covers most of canada & u. s. north of the ohio and missouri rivers. Carved landscape valleys and lakes, e. g. great lakes and finger lakes, new york. Deposited glacial material consisting of relative sorted deposits (drift) of gravel, sand, silt, clay to non-stratified drift or till, consists of particle sizes from clay to boulders. Pattern in southwestern ontario shows a zone of intense erosion with exposed bedrock, which grades laterally into an area that contains many drumlins and eskers, which grades into terminal moraines and finally extensive outwash systems. Niagara escarpment formed through differential erosion of soft rocks where not protected by strong carbonate caps. Crustal rebound weight of ice caused down warping of crust. Non-stratified drift (till: two methods of deposition:
