The effect of these glaciations was

Background Geology of the Nipissing area.

To understand what a unique area Nipissing is some understanding of the events shaped these lands is helpful!

All of North America is underlain by very old basement rocks now exposed in Canada and known as the Canadian Shield.

Nipissing is much like the many other communities on the Shield but has some differences!

Preview of CBC's Geologic Journey - Great Lakes

1.3 billion years ago (mya) there was collision between continents which was a world wide mountain building event named the Grenville Orogeny which produced the highest mountains the world has known!


If online click here for a very detailed technical explanation.

The northerly limit of this crunch was just north of North Bay (Marten River). Here is sketch of what that looked like:

These ancient rocks were even more cracked, deformed and metamorphosed: Then we drifted drifted around the equator awash with warm tropical seas!

The effect here was that:

But a great gash in the earth appeared!

About 425 million years ago (mya)

a graben (rift valley) formed and the land between two major faults (the Mattawa and the Petawawa) suddenly dropped downward about a kilometre.

This too, was part of much greater event


Strangely this graben systems was re-activated 175 million years ago!


Since then there have been over 40 ice ages - the last is called the Quaternary (which started 1,800,000 years ago) because it it has had four continental ice sheets, so far! Here is what the last ice sheet (The Laurentian) covered :

070210-GlaciatedNorthAmerica.jpg

The effect of these glaciations was :
This last ice sheet started to retreat from the Nipissing district about 12,000 years ago.
These shorelines are a place where evidence of the Paleo Indians would be possible to find, where excellent sand and gravel deposits exist but most important they are excellent storage and filtration systems for source water!

And we should look at the bedrock of this area because having a broken (by the Ottawa Bonnechere Graben event) granite dome (batholith) is exceptionally unique!


click on the image for a pdf that can be zoomed, panned and printed --


In the 1880's the J R Booth Lumber Company put in a supply(cadge) road and telephone line from their depot (on Trout Lake's) Four Mile Bay all the way up to their camp on Two Mile Lake (just north of the Widdifield Forest Provinical Park and this map!)   They couldn't have known it at the time but this completely traversed the North Wall of the Ottawa Bonnechere Graben! And 99% of this road is still in public hands!