The Pinhey Sand Dune system in Canada’s Capital is an end product of thousands of years of geological change.
Laurentide Glacier
In the Northern Hemisphere, thick continental ice sheets grew and retreated over the past 2.6 million years forming glacial periods. The last glacial period occurred between 120,000 and 11,500 years ago. The massive Laurentide ice sheet covered most of Canada. The movement of this 2-kilometre thick ice sheet gouged the earth and its colossal pressure formed deep depressions.
Champlain Sea
As the Laurentide ice sheet retreated 20,000 years ago, the gouges and depressions filled with water. This is how the Great Lakes and Champlain Sea formed. This ancient sea covered parts of Ontario, Quebec, New York, and Vermont in brackish waters. The Champlain Sea was a mix of ocean water due to its connection to the Atlantic Ocean and freshwater runoff from the glacier. This sea lasted from approximately 13,000 to 10,000 years ago and had a maximum depth of roughly 200 meters.
9,500 years ago, without the pressure of the glacier, the land started to rebound. Subsequently, the ground rose above sea level bringing the Champlain Sea to an end. As the water drained, fine grains of sand previously on the sea floor were exposed. This sand was formed by the action of the water (from the sea) and ice (from the glacier) on rocks over thousands and even millions of years.
Sand Dunes
From approximately 8,500 to 8,000 years ago this sea floor sand was moved to form the Pinhey Sand Dunes. During the growing seasons of this period, southwesterly winds slowly picked up the fine sand grains and deposited them in this area of Ottawa. The original Pinhey Sand Dunes system was extensive and covered over 1.5 million m2.
This is a unique habitat in Ottawa and has been home to many species for thousands of years however, more modern human actions have put them at risk.
Modern Era
In the early 1950s, tree planting programs introduced species that were not natural to the dunes, including red pines. Over time, these plants took up more and more space. These large trees and the organic matter they deposited on the sand turned the dunes into a pine forest.
In 2011 BCI in collaboration with the NCC took on the restoration and reclamation of the Pinhey Sand Dunes. Since then, 4 SITES have been cleared and we continue to restore and maintain the dunes. This involves protecting the plants and animals that rely on the unique dunes’ habitat for their survival.
Information was sourced from: Canadian Encyclopedia, Nation Capital Commission, NOAA National Centers for Environmental Information