Kettles are fluvioglacial landforms (which is a fancy way to say that they were made from the meltwater of glaciers) occurring as the result of blocks of ice calving (huge chunks of ice breaking away) from the front of a receding glacier and becoming partially to wholly buried by glacial outwash. Glacial outwash is generated when streams of meltwater flow away from the glacier and deposit sediment to form broad outwash plains called sandurs. When the ice blocks melt, kettle holes are left in the sandur. When the development of numerous kettle holes disrupt sandur surfaces, a jumbled array of ridges and mounds form, resembling kame (sand or gravel hills) and kettle topography.1 Kettle holes can also occur in ridge shaped deposits of loose rock fragments called till.2
Wilcox Lake is part of the Humber River drainage system, draining into the East Humber River. The drainage basin of the lake covers 260 hectares although the actual lake only covers about 55 hectares. The maximum depth of the lake is 17.4 meters3, which is deep considering that most kettles only get to be about 10 meters deep.
In order to log this EarthCache please complete the following tasks:
1. Assuming an average depth of 4 meters, try to calculate the volume of water in Wilcox Lake.
2. Examine the surrounding area and determine if there are any kame with this kettle. If so how high are they? If not, why not?
3. Approach the shoreline at both GZ and the provided waypoint and look for variations in the sediment (glacial till) what do you observe? Is there a pattern? Is there any recognizable difference? Explain.
Please email your answers to me and then log your find, if there is a problem I will let you know! Logs that include these answers must be modified or will be deleted. Remember to have fun and enjoy the beauty of this geolocality! Happy Caching!
References:
1. Bennet, M and Glasser, N: Glacial Geology:Ice Sheets and Landforms, page 262. John Wiley and Sons, 1997
2. Tarbuck, E and Lutgens, F:Earth, page 351. Prentice Hall, 2002
3. Lake Wilcox Town of Richmond Hill.