The Oak Ridge moraine formed 13,000 years ago when the glaciers began to retreat and southern Ontario was divided into 2 lobes, forming a crack that ran along the current ridgeline of the Oak Ridges Moraine.
Formation of Oak Ridges Moraine
The Oak Ridges Moraine contain a number of hydrological systems which include
- Permanent and ephermeral streams
- Wetlands
- Kettle lakes and ponds plus their catchment areas
- Seepage areas and springs, and
- Aquifers and other recharge areas
Included in these systems are 37 kettle lakes as well as 46 bogs and fens which are scattered over the moraine.
What is a Kettle?
Kettles are depression landforms that are created by a receding glacier. Many kettles are partially or wholly buried by glacial outwash when streams of meltwater carry sediments that form a broad outwash plain. When ice blocks fall away from the receding glacier and melt, a kettle hole is left behind.
Kettle holes can also occur in ridge shaped deposits of loose rock fragments called glacial till.
Kettle Pond
The depth of most kettles is less than ten meters and in many cases, the kettle hole will eventually fill with water, sediment or vegetation.
A kettle that is fed by surface or underground rivers or streams can become a kettle lake. Puslinch Lake in Wellington County, Ontario is the largest kettle lake in Canada. It is fed by surface runoff and underwater springs but there is no permanent inflow streams.
Alternately, if the kettle receives its water from precipitation, the groundwater table, or a combination of the two, it is termed a kettle pond or kettle wetland, if vegetated. Kettle ponds that are not affected by the groundwater table will usually become dry during the warm summer months, in which case they are deemed ephemeral and called Vernal pools or Vernal ponds
Vernal Pools
Ephemeral (often referred to as vernal or temporary) ponds are depressions which temporarily hold water on poorly drained soils. Vernal pools require sufficient catchment area for recharge; contours to hold water long enough to balance losses to infiltration or evaporation; and impervious soils to hold water. These are easily and frequently drained, often accidentally, when drainage is "improved", or water diverted due to minor alterations in soil elevations
Kettle Bogs
If the water in a kettle becomes acidic due to decomposing organic plant matter, it becomes a kettle bog. If the underlying soils are lime based and neutralize the acidic conditions, it can become a kettle peatland.
Kettle bogs are closed ecosystems that have no water source other than precipitation.
Bogs are one of North America's most distinctive kinds of wetlands. They are characterized by spongy peat deposits, acidic waters and a floor covered by a thick carpet of sphagnum moss. Bogs receive all or most of their water from precipitation rather than from runoff, groundwater or streams
pH levels
pH is a measure of whether water is acidic or basic.
Ponds have a higher or more alkaline pH level, with an average level for a healthy pond in the range of 7.0 pH.
Bogs typically have a more acidic pH level due to decomposing materials and the presence sphagnum or peat moss. Bog water typically has a pH range of 3.3 - 5.5, and transitional bog waters have a pH in the range of 4.5 - 6.0
Logging Requirements
This earthcache is located along a section of the Oak Ridge Trail (ORT) along the Uxbridge - Wilder Tract (Durham Rd. 1 / Brock Rd.) Parking is available along Brock Road near the trail head coordinates. Be sure to pull well off the road.
Note: You will need to take a sample of water to test the pH level to determine if this is a Kettle pond or a Kettle Bog. Answers submitted without proof of a pH level test will not be accepted.
To log this earthcache:
Rules:
All observations can be made from the footpath
Please send me your answers within 4 days of posting your found log. If there is more than one cacher in your party, include the names in your group. Only one person needs to send me the group answers. No spoiler photo's please. Found logs posted without proof you visited the site will be deleted.
Questions:
- Take a pH sample of the water and send me your results? (you can purchase pH test strips from Canadian Tire, Walmart or pet stores)
- Based on the results of the pH level, do you believe this is a Kettle Pond or a Kettle Bog? Explain your answer.
3. If this is a kettle pond, do you think this is a Vernal pool or will it remain filled with water annually. (Hint: use a stick to check the depth of the pond around the edge)
- What kind of plants can you observe growing in or by the water? Are they consistent with your determination of the type of wetland that is here?
- Is this an open or closed wetland? Is there an obvious source of water entering or exiting the wetland?
- Estimate the size of this wetland in square metres?
- Optional: Photos are optional and welcome
Note: Due to the requirement that a pH test is required, this earthcache is not going to be available during the winter months when the pond is frozen and covered in snow.
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