Stop #9, Kettle
Kettles, or kettle holes, are the most dramatic of the glacial features and the most well-known.
Kettles are deep bowl-shaped depressions. Kettles are formed when a block of ice from a glacier in the late stages of melting become completely buried. Though the glacier is long gone, these buried ice chunks eventually melt, forming a bowl-shaped depression.
The photo shows the kettle at stop #9. If you peer through the foliage you will see the other side of the bowl at about eye-level. This kettle is unique because it is small in size and largely free of water. This allows you to see the entire kettle. Its shape is almost a perfect bowl and is situated on a nearly flat landscape.
When a kettle is filled with water, it is called a ketttlehole lake. Several kettlehole lakes are well known and popular destinations for recreation. The most famous kettlehole lake is Walden Pond in Concord. The largest kettle in the world is Lake Ronkonkoma on Long Island. Kettlehole lakes are extremely deep compared to conventional lakes.
Whereas conventional lakes are fed by ground water runoff from one or more streams, kettlehole lakes are usually referred to as a “spring-fed”. The main loss of water in a kettlehole lake is by the slow process of evaporation, whereas conventional lakes lose water via a discharge stream. Whereas a conventional lake will replace all its water with fresh water in a matter of months, a kettle hole lake may take years to replace its water. This makes the habitat of a kettlehole lake more fragile since pollutants will persist for a long time. Utmost care must be taken to protect kettlehole lakes like Walden Pond. Aerial pictures of kettlehole lakes can be seen on the web.
Did you enjoy the walk? If so, I hope you will become an avid amateur glaciologist on your next outdoor adventure searching for glacial features.
Please follow the trail blazers or the interactive Google map for the 1 mile walk back to the Gray Reservation parking lot. The return trip has a steep downhill section that warrants caution.