| Crawford Lake | |
|---|---|
| Location | Ontario |
| Lake type | Meromictic |
| Basin countries | Canada |
| Surface area | 0.024 m² |
| Max. depth | 22.5 m |
| Surface elevation | 279 m |
Crawford Lake is located on the Niagara Escarpment,Southern Ontarios most significant landform which winds 725 km from Queenston to the islands off the Bruce Peninsula. In Ontario, the Niagara Escarpment has more than 100 sites of geological significance including some of the best exposures of rocks and fossils of the Paleozoic Era (235-570 million years ago), to be found anywhere in the world. Many interesting geological features occur at or near the Crawford Lake Conservation Area. A large island of bedrock (Milton Outlier) that was separated from the main escarpment includes well known landmarks such as Rattlesnake Point, Kelso Heights and the Nassagaweya Canyon. Crawford Lake is a rare meromictic lake that contains information about the natural and cultural history of the area. Located atop the Niagara Escarpment, this small deep body of water has limited circulation and little oxygen below 15 metres (total depth of 24 metres). This ensures the preservation of annual deposits of sediment called varves. This analysis revealed the trends and sources of air pollution over approximately 150 years. Similar to counting growth rings on a tree, these doubled layered bands can be accurately dated. Studies of the sediment led to the discovery of the nearby Iroquoian village. The extensive forests and escarpment cliffs at Crawford Lake provide habitat for a wide diversity of flora and fauna. The shallow calcium rich soil and rocky outcrops sustain many unique plants (eg., the maidenhair spleenwort and walking fern, the carnivorous sundew and the exquisite yellow ladys slipper). Warblers and woodpeckers abound while Turkey Vultures can be seen soaring through the Nassagaweya Canyon. White tailed deer, raccoons, chipmunks and red squirrels are some of the common mammals found at Crawford Lake.
