Manitoulin Island's special 'crack'

Northern Ontario explorer Bill Steer calls the rocks on Manitoulin Island "oddities."

One of the unique features on the largest freshwater island in the world are alvars, naturally open habitats that look like ancient cracked pavement.

"Most people know a crack when they see one, but that doesn't mean they understand or have thought much about cracks like the clints and grikes of Manitoulin Island," Steer said.

Grikes are cracks formed in rock as it dissolves in water.

Clints are the chunks of rock formed by the grikes.

The grikes collect soil and plants take root.

"It is a rare and sensitive ecosystem that is not found outside the Great Lakes basin," Steer said.

The areanorth of Providence Bay is an outstanding example of an alvar with several ferns, stuntedjunipers and exposed rock.

Manitoulin Island stretches 130 km long and 40 km wide in Lake Huron, an extension of the BrucePeninsuaand the Niagara Escarpment.

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