Ancient Glacial Lake and Present Day Shorelines EarthCache

The above co-ordinates bring you to a ridge on Green Street in Port Elgin. There is ample parking on both sides of Green Street, at the top of the hill, to accommodate beach lovers in this tourist town on the way to the co-ordinates. To log this Earthcache: please visit both sets of co-ordinates to arrive at your answer and supervise children around the road and water areas at all times.

In the Past

About 1.6 million years ago in the middle of the Pleistocene Epoch, the earth’s temperature cooled triggering the latest series of ice ages. Great ice sheets grew to cover most of the North American continent and periodically withdrew again as the earth’s temperature rose. The presence of the ice sheet caused the Earth’s surface, below, to change significantly. The movement of the ice flattened some areas where mountains had been and the weight of the ice depressed the earth creating deep basins where smaller valleys once lay. Some of these basins would later become the North American Great Lakes.

When temperatures rose and the ice receded, the land rebounded freed from the weight creating new hills and ridges. Most of the melting water near the edge of the glacier flooded the basins forming lakes. This cycle repeated several times and ended with the formation of a glacier approximately 100,000 years ago. This large glacier, as thick as 4km in some spots, began to recede about 14,000 years ago; its melt waters filled the glacially formed basins creating Lake Algonquin among others lakes.

Today on Lake Algonquin’s Shoreline

The above co-ordinates bring you to a ridge on Green Street in Port Elgin. There is ample parking on both sides of the road, at the top of the hill, to accommodate beach lovers in this tourist town on the way to the co-ordinates along Green Street. Look west toward the lake. Here, as the high-level Lake Algonquin drained approximately 10,000 years ago, the elevated shoreline remained exposed. You are standing on the ancient shoreline of Lake Algonquin.

Take an elevation measurement here ~ N 44° 26.470 W 081° 23.953.

Today on Lake Huron’s Shoreline

Approximately 2,000 years ago, Lake Algonquin gave birth to what we know now as Lake Huron and Georgian Bay.

Various drainage routes for the glacial waters of Lake Algonquin were created as the land shifted including a significant one to the Ottawa River near North Bay. The present day drainage path through lakes St. Clair, Erie and Ontario to the St. Lawrence River, and eventually to the Atlantic Ocean, keeps the lakes at their current levels creating the five Great Lakes, as we know them today.

Lake Huron was named by the French explores after the Huron Indians who lived in the area. In surface area, it is the 2^nd largest of the five Great Lakes. In water volume, it is the 3^rd largest of the five Great Lakes. Its island, Manitoulin Island, is the largest freshwater island in the world.

The earth continues to change, rising slowing in the north, weather patterns change too and in a few tens of thousands of years (unless humans intervene sooner) the Great Lakes area will look different than it does today.

Follow the 2^nd set of co-ordinates (next paragraph) to the edge of Lake Huron’s shoreline. There is a large beach parking lot available down here.

Take an elevation measurement at this second set of co-ordinates ~ N 44° 26.524 W 081° 24.250.

Note the sand on the beach. This beach is very similar to the ancient beaches around Lake Algonquin, one of which still exists under the town of Port Elgin east of the hill. Our backyards and gardens here consist of very sandy soil.

Question:

1) Assuming the top of the escarpment, at your first elevation check, is your shoreline of Lake Algonquin, how far underwater would you be now standing at the present day shoreline of Lake Huron?

Those who send an answer will receive a bonus.

Photos of you in the area are always nice to see and add to the interest of the geocache page. Please consider adding some of your own.
Favourite: If you like this Earthcache, please consider giving it a favourite point so others will know you enjoyed the experience. Thanks a bunch for visiting ~ hope you had fun.

Congratulations to Muskoka Pearl and junebug13 for FTF!

CedarNCo have earned (GSA) Geological Society of America's highest earthcache level:

Platimum Earthcache Level is awarded by Geo Society .org for visiting and logging 20 or more EarthCaches in 5 or more states/provinces/countries and have created 3 or more EarthCaches.