Ordovician-Silurian: escarpment

17.9.09

escarpment

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Niagara Escarpment

Essentially, the Escarpment is a ridge of rock several hundred metres high in some locations, which forms the outer ring of the Michigan Basin; it was created through a long, complex geological process which includes its having been in the Silurian period, a sea. The Niagara section of this (rough) ring, capped with dolomite, stretches 725 kilometres (450 miles) from Queenston on the Niagara River to Tobermory at the tip of the Bruce Peninsula. Today, in Ontario, the Escarpment contains more than 100 sites of geological significance including some of the best exposures of rocks and fossils of the Silurian and Ordovician Periods (450 to 500 million years old, from the Palaeozoic Era) to be found anywhere in the world.

The rock layers of the Niagara Escarpment date from the upper Ordovician (445 million year ago) to the lower Silurian era (420 million years ago). The rock below, and east of the escarpment is mostly Ordovician limestone. The rock on, and west of the escarpment is mostly Silurian dolostone. Because of this, the escarpment was once called the Silurian Escarpment.

Ordovician-Silurian

17.9.09

escarpment

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Cabot Head Sunrise

FLOWERPOT ISLAND

ORDOVICIAN-SILURIAN

Niagara Escarpment

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