Rock resources

My recent vacation was in the Parry Sound district and North Bay. They’re both in the very interesting Grenville [geological] Province within the political province of Ontario. Much of the rock is spectacularly banded gneiss, cliffs of it in alternating pink and black or black and white. The little rock sample of the left is gneiss. It’s from a rock-sample web page.

The area around Lake Nipissing (where the city of North Bay is) is the oldest part. It has formerly sedimentary rocks that were metamorphosed by heat and pressure. Some of the layers are fantastically folded.

The youngest area is the Parry Sound district, on Georgian Bay, which contains the remnant of an arc of volcanic islands that formed thousands of miles away. The rocks aren’t as old as I thought: about 1 billion to 1.8 billion years old.

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