The Georgian Bay Land Trust (GBLT) celebrated a busy summer, welcoming old friends and new who came out to explore and spend a couple of afternoons “geologizing” on two of the GBLT’s protected properties; The Lizard in Cognashene, and West Lookout Island Reserve in Pointe au Baril.
Lizard and Lookout Point geology is globally noteworthy.
Cottagers and residents joined Professor Nick Eyles on Rock Walks at two of the Georgian Bay Land Trust’s protected properties: The Lizard in Cognashene and West Lookout Island Reserve in Pointe au Baril this summer to about the distinctive geology.
These rock walks are part of the GBLT’s community outreach efforts intended to educate the public and promote an appreciation of this special area. As a not-for-profit registered charity, the GBLT’s goal is to protect the unique archipelago of the Eastern Shore and North Channel of Georgian Bay through the securement and ongoing stewardship of land that is of ecological, geological and historic importance. A grassroots, primarily volunteer-based organization, the Georgian Bay Land Trust is fortunate to enjoy the professional support of various individuals such as Professor Nick Eyles who led the rock walks, along with the support of the various communities that make up this unique area.
The Thirty Thousand Islands is the name given to the largest archipelago of freshwater islands in the world, extending over 250 km of rock-strewn coastline on the eastern side of Georgian Bay between the French River in the north and Honey Harbour in the south. Strikingly beautiful outcrops of complexly folded billion-year-old gneiss dominate these remote rocky islands and their wind-bent stands of white pines. The low-lying islands appear to dissolve into the sky and lake water, creating the surreal and eerie landscape immortalized by the Group of Seven. The area has been named a UNESCO World Biosphere Reserve for its aquatic and terrestrial habitats, but its geology is no less worthy of global note as it records the deep roots of billion year old mountains that dwarfed the Himalayas.
According to legend, the Huron giant Kitchikewana, overcome by grief at being spurned by the princess Wanakita, hurled rocks into Georgian Bay creating the many islands. The dominant rock type throughout the 30,000 Islands is gneiss and the islands result from glacial erosion along narrow bedrock structures such as faults and fractures. The dissected topography was then flooded by the relatively recent (last 8,000 years) rise of Lake Huron, isolating thousands of islands large and small. At that time much of the floor of what is now Lake Huron was dry land. This may be because the climate was drier and much warmer (a brief time period geologists call the ‘Hypsithermal’). Also, much of central Canada to the east was still tipped down under the weight of the recently melted ice sheet, allowing the Great Lakes to essentially drain out through the St. Lawrence (sea level was low also). As the land slowly rebounded back, the level of the Great Lakes has grown higher over the past 8,000 years and the 30,000 Island areas came into existence.
The 30,000 Islands are the smoking gun of plate tectonics and a reference point for all geologists. They are part of the Central Gneiss Belt (CGB) of the Grenville Province. The latter extends from Texas to Labrador and the CGB marks intense crustal deformation when continents were colliding together to form the supercontinent Rodinia starting about 1,400 million years ago (1.4 billion).
The Georgian Bay Land Trust aims to ensure the 30,000 Islands remain a viable ecosystem in the face of development. We hope you will join us next summer for one of our rock walks. Information can be found on our website at www.gblt.org.