Wild Northerner Magazine Fall 2017 - Page 50

Manitoulin Island holds history lessons

BY BACKROADS BILL

For Wild Northerner

A destination can be unusual because it is interesting or different. Manitoulin Island is blessed with incredible natural beauty mainly because of the rocks. Its rocks are oddities. We can learn much from these anomalies. Take the time this fall to experience its uniqueness. Most often you need a guide.

Spirit Island

Follow this through. It is the 172nd largest island in the world and is the 31st largest in Canada. Known as the “Spirit Island”, this island itself has 108 freshwater lakes, some of which have their own islands; in turn several of these ’islands within islands‘ have their own ponds. Lake Manitou is the largest lake in a freshwater island in the world, and Treasure Island in Lake Mindemoya is the largest island in a lake on an island in a lake in the world. These facts alone give the island an atypical introduction.

It is about 130 km long and 50 km wide and its intriguing landscape resulted from the action of ancient rivers and glaciers that altered the soft bedrock. These actions are what make the island distinctive. It is an extension of the Bruce Peninsula and the Niagara Escarpment.

When compared to the granite of the

Canadian Shield found in most of Northern Ontario, it is the white quartz and limestone rock and the alvars that make the island the exception. Five hundred million years ago, Paleozoic limestone was deposited in shallow, tropical seas; at the time, over top of the bumpy landscape of the Canadian Shield. Slowly the island was buried by these limestone sediments made from millions of sea shell pieces.

The accumulation of the invertebrates’ hard parts after their deaths generated the sediment; all of this hardened into the limestone features. Limestone is a hard sedimentary rock consisting of calcium carbonate, formed by the deposition of plant and animal remains on the sea floor and is thus known as a calcareous rock. You are standing at the bottom of a sea. Limestones often contain the visible remains (fossils) of shells and corals, and this is another feature of the island. The rocks here are different.

You will see lots of dimples in the limestone rocks of Manitoulin caused by underwater dissolution into the tropical sea of 43 million