Crater in NE Canada?

What I don't understand is that if the crater in the first pic in the first post is all land, shouldn't it be mostly just a giant lake, not some kind of grassland or mountain whatever its showing. After all, is it really that old, that clumps of land fills up in the crater?

It's over 200 million years old.

It used to be a couple of lakes and some rivers but the government built hydro dams and the circle with the island was the end result.

Originally posted by deltaboy
What I don't understand is that if the crater in the first pic in the first post is all land, shouldn't it be mostly just a giant lake, not some kind of grassland or mountain whatever its showing.

Some of the rocks cooled from impact melt are quite hard so impact melt could have formed harder formation to lowest part of crater which resisted erosion better leading to outer/higher areas inside crater bowl to erode faster.

Here's what the area looked like before the hydro dams were built.

external image

I believe it's called Nastapoka Arc.

en.wikipedia.org...

The formation may have formed due to an ancient impact crater or glacial unloading. What's weird is how Belcher islands are still standing. If it was a crater, the Belcher islands would no longer be there.

Originally posted by MrPoporing95
I believe it's called Nastapoka Arc.

en.wikipedia.org...

The formation may have formed due to an ancient impact crater or glacial unloading. What's weird is how Belcher islands are still standing. If it was a crater, the Belcher islands would no longer be there.

It's a "complex crater" in which "uplift peaks" are formed in the center of the crater due to a process called elastic rebound. Right after the imact, the ground acvts elatsic and almost fluid, so the center gets pushed in, then it rebounds outward. Soon after the outward rebound, much of the impact energy dissipates and the ground loses its elasticity, thus forming peaks and mountains. The islands in the center is probably what's left of those mountains after millions of year of erosion.

Complex Crater - Wikipedia
Complex Crater

The Moon is full of complex craters with central uplift areas that were created by elastic rebound:
www.universetoday.com...


Think of the process as being like a water droplet witting a smooth water surface. The center of the "crater" made by the water droplet rebounds to form a small peak before falling back to the surface. In the case of these craters, the energy dissipates quickly, and the ground loses elasticity before it could "fall back" to the surface.

Water droplet:



[edit on 5/11/2010 by Soylent Green Is People]

reply to post by UnMature


A nice place it is. I have heard stories about huge fish in the reservoir. Since it is a far place from the cities, not many go there and with over 400 feet deep in places, the fish can grow undisturbed.

I have pictures I took a few years ago while on a job at a nearby dam.



This is the Manic 5 hydroelectric dam. This is the dam that formed the reservoir. The most impressive structure i've seen. There are a few others downstream. This is called the Manic-Outardes complex.




This is the manicouagan reservoir seen through the chainlink fence. Before 911 and before some stupid tv reporter went inside, there was absolutly no security there, you could go and touch the thing, the road even passed on the structure. But now it is guarded and monitored.



Myself going down to inspect the gate of the spillway on the nearby Outardes 4 dam. This is what I call a good commute to work.

Cheers

[edit on 12-5-2010 by grandnic] resize pictures


[edit on 12-5-2010 by grandnic]