/lit/ - Literature

What is on my mind are the Laurentian Mountains in eastern Canada.

When you compare them to other mountain ranges, they are rather unimpressive, looking like low rolling, very rounded hills. The reason they look like that is because they are actually one of the oldest mountain ranges in the world.

The Laurentian Mountains formed during the Grenville Orogeny, from 1.2 to 1 billion years ago in the Proterozoic eon. That's in the Precambrian, meaning those mountains did not have any plants or terrestrial life on them for millions of years.

In comparison, the Himalayas are the youngest mountains in the world at around 50 millions years old. The Appalachian mountains, which look very similar to the Laurentians, are only around 480 million years old. The Appalachians actually sit on the Grenville province (part of the Canadian Shield) in some parts of eastern Canada.

If we still see them today after 1 billion years is because they used to be of the scale of the current Himalayas. Thousands of meters in altitude. But time and many, many cycles of glaciations eroded them almost completely.

Only the roots of the mountains remain visible today. Those rocky, trees covered hills were once around 35 km below ground. At such depths, the pressure and temperature were immense and that's the reason they are made of high grade metamorphic rocks.

That is what is on my mind.
Ancient mountains.