When we started out we mused about old oceans
lying buried inside our North American continent. Without wishing
to look dreamy about it, one could conjure up visions of archipelagoes
in the south Pacific. So, let's dream about it. Where? In the middle
of our prairies, of course, in Saskatchewan, and in parts of Manitoba.
We are coming back to the Trans-Hudson Orogen (THO), which now is
the eroded remnant of a series of collisions. Once it had posed
as an ocean with island arcs in a rather milder setting —
before the big crunch of Superior Province (in the southeast) against
Hearne-Rae Province (in the northwest) put an end to this, about
1,900 to 1,800 Ma. The THO encompasses a particularly complete example
of tectonic events which welded together a number of pre-existing
minicontinents into the North American continent. In Saskatchewan-Manitoba
this orogenic belt is 500 km east to west, one of the best preserved
examples of a collisional orogen.
It includes areas in which mining companies have shown a keen interest.
And west of the THO lies the Alberta Basement which also is of interest
to exploration companies, mostly with respect to oil and gas. We
will go west right after we have looked at the THO.
We ourselves are, of course, not an exploration company, and we
are not looking for gold or oil or diamonds. LITHOPROBE is engaged
in fundamental research. Nevertheless, our studies help trace and
understand the geological framework in which minerals and oil and
gas deposits form, and diamonds may find their way to the surface
through volcanic pipes, from very deep-seated sources. And where
appropriate we address the problem of why we have earthquakes or
volcanoes.
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