I said in a previous post that I would try to liberate some of the papers behind the paywall, summarizing them, as a harmless old fool, hoping that nobody gets mad!
This paper was right in front of me, so I'll start with it: "A seismic-based cross-section of the Grenville Orogen in southern Ontario and western Quebec". You can see all the details on how to pay at the web site.
This paper uses some of the data records that we helped dig out from the oil industry vaults, namely the 1971 deep marine vibroseis. You can tell the tone of the paper by looking at this illustration:
Note that anything covered by the kettle-scum of the Paleozoic is ignored! This was written by the pure 'hardrock' guys! Of interest to inquiring minds, is the cross-section of Corridor II, which is as far south as they dared put it. Here it is:
You have to click on it to see anything! Note the beautiful megathrusts (3 of them!) at the western end. They are shallow dipping and go practically to the Moho. In the maps, they never go under the flat junk, but the lake seismic surveys all show them, clear as a bell. These happy triplets, the 3 Sisters I like to call them, become quite important when one tries to make a serious stab at Ontario geology.