This Earthcache takes you to the Parkhill Conservation Area, an 800-hectare conservation area is result of efforts to control serious flooding and erosion problems downstream. The Parkhill Dam and reservoir were constructed in 1969 to create a storage area to regulate the waterflow of Parkhill Creek. There is no cost to access the area. Dogs are permitted but must remain on leash at all times. Biking, camping and campfires are not permitted in this area. The terrain is mostly flat and grassy with no formal trails in the area. The area near the lookout is very steep so please use caution especially with small children and pets.
The posted coordinates for this cache take you to the Scenic Lookout spot, overlooking a small area of the Wyoming Moraine.
WYOMING MORAINE
Between Exeter and Lake Huron is the long ridge of the Wyoming Moraine, the largest and most prominent physiographic feature in the Grand Bend/Parkhill area. This massive pile of glacial debris runs parallel to the Lake Huron shoreline and marks the edge of the Huron Lobe of the ice sheet that covered this area 15,000 yrs ago. The Ausable River meanders southwards on the east side of this moraine, past Ailsa Craig and Nairn. South of Nairn, it turns westward, still following the edge of the moraine as it too curves westward following the Lake Huron shore. Finally at Arkona the river makes a breakthrough! It managed to find a way across the moraine and poured across cutting a deep narrow valley known as a spillway.
The moraine is manifest as a belt of hummocky topography standing 30 to 60 m above the surrounding terrain. The belt is approximately 8 km wide and roughly parallels the Lake Huron shore in the map-area. The moraine is best developed in the north, where three distinct parallel ridges are visible. These three ridges merge near the town of Dashwood as the moraine is traced southwards; the morainic topography be comes more subdued as one approaches the town of Wyoming.
But what is a morraine?
A moraine is material left behind by a moving glacier. This material is usually soil and rock. Just as rivers carry along all sorts of debris and silt that eventually builds up to form deltas, glaciers transport all sorts of dirt and boulders that build up to form moraines.
To get a better idea of what moraines are, picture yourself with a toy bulldozer on a lawn that has a bunch of dry leaves all over it. When you run the bulldozer through the leaves, some of them get pushed aside, some of them get pushed forward, and some of them leave interesting patterns on the grass. Now think of these patterns and piles of pushed-away leaves—moraines—stretching for kilometers on the Earth.
Moraines only show up in places that have, or used to have, glaciers. Glaciers are extremely large, moving rivers of ice. Glaciers shape the landscape in a process called glaciation. Glaciation can affect the land, rocks, and water in an area for thousands of years. That is why moraines are often very old.
Moraines are divided into four main categories: lateral moraines, medial moraines, supraglacial moraines, and terminal moraines.
Lateral Moraine
A lateral moraine forms along the sides of a glacier. As the glacier scrapes along, it tears off rock and soil from both sides of its path. This material is deposited as lateral moraine at the top of the glacier’s edges. Lateral moraines are usually found in matching ridges on either side of the glacier. The glacier pushes material up the sides of the valley at about the same time, so lateral moraines usually have similar heights.
If a glacier melts, the lateral moraine will often remain as the high rims of a valley.
Medial Moraine
A medial moraine is found on top of and inside an existing glacier. Medial moraines are formed when two glaciers meet. Two lateral moraines from the different glaciers are pushed together. This material forms one line of rocks and dirt in the middle of the new, bigger glacier.
If a glacier melts, the medial moraine it leaves behind will be a long ridge of earth in the middle of a valley.
Supraglacial Moraine
A supraglacial moraine is material on the surface of a glacier. Lateral and medial moraines can be supraglacial moraines. Supraglacial moraines are made up of rocks and earth that have fallen on the glacier from the surrounding landscape. Dust and dirt left by wind and rain become part of supraglacial moraines. Sometimes the supraglacial moraine is so heavy, it blocks the view of the ice river underneath.
If a glacier melts, supraglacial moraine is evenly distributed across a valley.
Ground Moraine
Ground moraines often show up as rolling, strangely shaped land covered in grass or other vegetation. They don’t have the sharp ridges of other moraines. A ground moraine is made of sediment that slowly builds up directly underneath a glacier by tiny streams, or as the result of a glacier meeting hills and valleys in the natural landscape. When a glacier melts, the ground moraine underneath is exposed.
Ground moraines are the most common type of moraine and can be found on every continent.
Terminal Moraine
A terminal moraine is also sometimes called an end moraine. It forms at the very end of a glacier, telling scientists today important information about the glacier and how it moved. At a terminal moraine, all the debris that was scooped up and pushed to the front of the glacier is deposited as a large clump of rocks, soil, and sediment.
Scientists study terminal moraines to see where the glacier flowed and how quickly it moved. Different rocks and minerals are located in specific places in the glacier’s path. If a mineral that is unique to one part of a landscape is present in a terminal moraine, geologists know the glacier must have flowed through that area.
Details About this Earthcache
In order to answer the questions, you will need to visit the scenic lookout at the posted coordinates and answer some questions about the morraine you are standing on. This earthcache is available from dusk to dawn, seven days per week, 365 days per year.
As with all of my ECs, I am not looking for PhD thesis level responses, but I am hoping that you take some time to enjoy the area and learn something new. Please include a list of all cachers with your answer, if answering for more than one caching name.
For large groups: I am happy to accept the answers for groups from one person, but each person logging should have their own, separate, mandatory photo showing you did actually visit the site.
Other photos are welcome of yourself or your group in the area. Please feel free to log as found as soon as you send your answers and I will contact you if you have any questions. Logs without answers sent may be deleted if answers are not received within 5 days of logging.
Questions:
1. According to the Species at Risk sign near the posted coordinates, Parkhill Creek used to be a part of the ___________________. (3 words)
2. Take an elevation reading using your GPS or device at the top of the lookout. What is it?
3. The elevation reading on the shores of Lake Huron, approx 15km away, measures 175m. Based on this information, how tall is the moraine at this location?
4. Have a look across the water at the Wyoming Moraine, as well as what is under your feet. Describe, to the best of your ability, what type of material or glacial till was left to form the Wyoming Moraine. Try to be as specific as possble, (eg Large boulders made of metamorphic rock vs Rocks)
5. Have a look at the basic geography of the area, and based on the description, determine what type of moraine you think this is. Give reasons as to why you believe this.
6. Mandatory: take a photo of yourself or your signature item at the posted coordinates, looking out over the water. You do not need to show your face in the photo, but it does need to be clearly identifiable as you in the photo.
Permission for this cache was obtained from the ABCA as of 9/19/2023.