lithoprobe logo
home | contact | search about | transects | publications | links | classroom/media 
media > slideset > the Growth of Canada >

Tectonic provinces of the North Atlantic region.

Earth's dynamic forces (or tectonics) didn't stand still at the southeastern side of Nain Province, either. Here the Makkovik Orogen was formed about 1,800 Ma.
Have a look at the heavy, serrated lines on this map. They show the contacts along which one geologic unit was thrust against the other. Thus, they denote regions of gigantic thrust faults. The notches point into the direction whence the thrust came. Actually, that isn't quite precise to say. The notches are on the side of those rock formations which were thrust on top of the formations on the other side. Now, where these lines of thrust, or thrust faults, meet, there is only one survivor — namely the last one, which overrides all the imprints which had been left before.

We can see this on the map, where the later Labrador Orogen thrust cuts across the former New Quebec and Torngat Orogens (or mountain ranges), as well as the central core of the Rae (Churchill) Province between them. The thrust of the Labrador Orogen occurred at about 1,700 to 1,650 Ma, or 100 to 150 Ma after the Makkovik thrust. The reason for the seemingly imprecise figures is that these processes don't happen in one bang, but proceed over a longish geological time period. Continents and ocean plates don't move as fast as an express train, but they are even harder to stop. Some 600 Ma after the Labrador Orogen had been pushed together another, and much stronger, push from approximately the same direction created the mighty Grenville Orogen, reworking the eroded remnants of the Labrador Orogen in the process.

previous page next image
home | about | transects | publications | links | classroom/media | search | contact