Crawford Lake: A Partially Developed Plunge Pool

4.0 Introduction

4.2.1.d Crawford Lake: A Partially Developed Plunge Pool

Niagara Escarpment
A Virtual Tour Commentary Stream Capture by Roger Chittenden

Glacial melt waters create plunge pool – Crawford Lake and lead to stream capture ! For at least half a million years and probably much longer, warm periods and ice ages have alternated in a fairly regular pattern: twelve thousand years of warmth have been followed by about one hundred thousand years of cold. The current warm period is now more than twelve thousand years old, and if we had not warmed the climate up by burning fossil fuels, we should possibly be heading toward another ice age, which would destroy every city as far south as the Missouri River. On the other hand, if global warming continues to the point where the Greenland Ice Cap melts, as it has in the past, sea level would rise about twenty feet. That is the dilemma facing mankind. The following photographs show some of the landforms created by the beginning of global warming 12,000 Years Before the Present (YBP)

1		About fourteen thousand years ago, the last glacial advance into the Lake Ontario basin lapped up onto the top of the Niagara Escarpment. This open-ended valley at Rattlesnake Point is called Nasawageya Canyon. It is a glacial trough. That means it was filled with ice that protruded above the Canyon Walls.
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