Geological History

The history of the Falls began about 600 million years ago. In this era a broad shallow sea covered most of North america. Under the water already the rocks of the former canadian shield were present. During about 100 million years passing along soft sediments were deposited over the Pre-Cambrian rocks. After the Appalachian mountains were formed rivers flew in new patterns carriying mud westward which cemented by eons forms the Niagara Gorge.

About 300 million years ago the inland see drained away and the sediments layed about 5 km high above the Pre-Cambrian rocks. Fifty million years later great rivers flew all over the continent forming randomly patterns into the sediments. These patterns formed later on the basins of Lakes Huron and Michigan and later Erie and Ontario.
During all the time Canada slowly moved north into a region with much lower temperatures than all the time before. Four times in rapid succession Canada and most of North America was covered by ice shields. Those glaciers formed the landscape to the shape we know nowadays with its scrubbed stones round like a stone out of rapid waters.

The ice slowly drew back about twelve thousand years ago opening a connection to the lower Hudson valley. The waters of the former Ontario basin drained through this connection. After years of sinking water levels the Niagara Excarpment was exposed. Lake Erie which resides on a higher level began to send its waters over this Escarpment forming the ancestor of the Niagara river.
After all of the ancient glaciers disappeared the Earth crust relieved from the weight of the ice reascended to a new level which turned the direction of flow. So the Niagara river was formed and with it the Falls over the Niagara Escarpment.
After this time no major changes in the actually known structure of the Canadian shield appeared.

Niagara landscape
last reviewed on: August 19, 2004)
Since the time when the glaciers started to retreat about 12000 years ago the Niagara Falls moved from about 11 km down the river to their actual location by erosive destruction of the ground. Also nowadays the Falls move up to 1 m per year against the rivers direction. Some scientists claim that the Falls will completely disappaer after a certain time even while the erosion seems to be much slower than in former times.

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