Trekking through Time and space
… well, not Space out there, but space here on Earth.
We all trek through the time that is allotted to us during our life, and if we’re fortunate, as I have been, then we can also do some exploring of spaces on Earth. (And also into the Earth, in my own case. But I digress.)
So, let’s start off with one image, showing my wife and I posing on top of the “Big Rock” also known as the “Okotoks Erratic”, located near (you guessed it) Okotoks on the Alberta prairies in Canada.
Now, once you have finished feasting your eyes on the two energetic and photogenic youngsters, do consider those Rocky Mountains on the horizon. The reason for this image is not to talk about our trekking through Canada back in 2017 (OK, maybe just a little bit) but rather about the trek that this rock had made through time.
Let’s zoom out a little.
We can now clearly see the layered, sedimentary nature of the rock, which gives us a bit of a clue about its trek, from long ago. The rock (a feldspathic quartzite, if you really want to know) was brought to this place by a glacier, all the way from those Rocky Mountains in the distance.
Somewhere between 12,000 and 17,000 years ago, it was deposited onto a glacier by a landslide, in the upper reaches of the Athabasca River valley. Along with a lot of other material from the same source, the glacier moved it southwards and eastwards. The rock was not ground into smaller bits, or rounded or polished, as other rocks are that are pushed around by glaciers. That is because it was on or near the top of the ice, and stayed there until the ice melted.
But this rock is actually older than that.
The grains that formed this rock were originally deposited into a shallow sea during the early Cambrian, somewhere between 532 and 513 million years ago.
After which, the entire sedimentary package of rocks was buried under other sediments, and when plate tectonics pushed from the West, the rocks were pushed upwards and eventually eroded to form the Rocky Mountains we see today. And some of them tumbled onto a glacier, traveled across the land until the transport ran out of steam (or actually, ice) and settled onto the prairie.
As a final indignity, tourists come to look at them and climb onto them. Now I must add that I have since read online that one is NOT supposed to climb onto the rock, but the various signs that were posted there at the time, did not say that it wasn’t allowed, just warned us to be careful. (Or that’s what I remember, anyway.)
Anyway, my excuse is that I’m a geologist. We do all sorts of things to rocks; we even lick them. I didn’t lick this one, instead I sucked on a very nice Grasshopper from the nearby Big Rock Brewery.
Our visit to the Okotoks Erratic was at the very start of our trip from Calgary to Vancouver in the summer of 2017. But that’s a trek to be discussed on another day.
