Real Talk!

The science of geology goes way beyond rocks and minerals. Geology is the study of planet Earth- it encompasses theories of the whole how/what/where/when of our planet was formed and continues to be shaped.

Scientists have identified three layers that comprise the planet Earth: the crust, the mantle and the core. The crust is a hard layer of rock that’s about 50 kms thick and includes the land masses that we live on, as well as the lining of the ocean floor. The Earth’s mantle is a semi-molten layer, about 3, 000 kms thick, and rich with the elements magnesium, silicon and iron. The core is believed to be hot, molten liquid nickel and iron.

In the late 19th and early 20th centuries, some scientists believed that the continents were floating. Observing remarkable similarities in the shapes of coastlines, fossil discoveries and mountain ranges on opposite sides of the ocean, it was easy to image that the planet had once been one large mass that slowly broke apart. The emerging theory was known as continental drift.

In the 1940s, geologists realized that it wasn’t so much the continents as it was the Earth’s crust that was cracked into pieces that were floating on the mantle part of the earth. Ontario, a part of the crust, has been described as a “huge raft” of rock that floats on the surface of our planet. Geologists refer to this raft as a plate and have come to understand the changing crust through a theory known as plate tectonics.

It is believed that there about 10 major plates and numerous smaller plates that make up the Earth’s crust. Ontario sits in the center of the enormous North American plate.

Today, there’s a growing theory that the continents do collide and then drift apart over millions of years, in an ever-repeating pattern. Geologists have learned to read the history of a continent and can identify the very location of its most recent beginning- they call this the craton. Right now, the biggest craton in the world is the Canadian Shield.

Geologists have divided the Canadian Shield into seven geological areas that they call provinces: Bear, Churchill, Grenville, Nain, Slave, Southern, and Superior. The Canadian Shield forms the core of North America and occupies almost half of Canada's surface- and half of the Canadian Shield lies in Ontario. Ontario’s Highlands region is located in the Grenville province.

The Grenville area has been subject to numerous geological processes, including volcanic activity, glacial scouring, metamorphic activity and intense faulting and folding. Here, you see the remnants of a very ancient mountain range whose scale once rivaled the Himalayas. There were once active volcanoes and the first discovery of gold in Ontario was in this area, too. Historically, there have been countless mining operations throughout the region which have harvested all kinds of minerals including: talc, mica, quartz, corundum, marble, uranium and sodalite.

Quite an exotic playground for the amateur geologist!