Introduction

MV J. Ross Mackay: scientific research vessel

This poster illustrates the important geologic and geomorphic features of the Rideau Lakes between Smiths Falls and Westport, Ontario and briefly summarizes the geological history. This part of the Rideau Waterway is one of the most scenic and heavily used recreational areas in Ontario.

This area straddles the boundary between Paleozoic sedimentary bedrock and the Canadian Shield. Similar to most of Canada, it was glaciated a number of times during the last 2 million years. At the end of the last glaciation, it was covered, first, by an expanded stage of present day Lake Ontario and later, by an inland sea that formed a shallow arm of the Atlantic Ocean.

The Rideau Lakes are quiet-water settling basins for mineral and organic sediments. They received large quantities of fine-grained mineral sediment during the melting of the last glacier.

Since deglaciation they have continued to accumulate mineral and organic sediment, but at a much slower rate.

The data on bottom and sub-bottom sediments presented in this poster were collected on a scientific cruise undertaken by Geological Survey of Canada between June 29 and July 6, 1999. Information on the bedrock and surface materials along the shores of the Rideau Lakes was extracted from existing Geological Survey of Canada maps and reports.

Poster

This Open File is available at the Geological Survey of Canada Bookstore.