Along highway 7, between Okotoks and Black Diamond Alberta is a large rock at the side of the road. It is known as Big Rock, or the Okotoks Erratic and it is hugely significant both to the area and to the history of the earth.

Big Rock wasn’t always here, in fact, it started life near Jasper, some 450 km northwest of its current location. But how did it come to be here, I hear you ask! Well, it tobogganed here. No, only kidding, it actually took a ride on a glacier some 10,000 to 30,000 years ago and ended up being deposited right where it now sits.

It is made of Quartzite and measures approximately 41 x 18 metres (135 x 60 ft) and 9 metres (30 ft) tall, weighing in at an estimated 16,500 tonne. It makes for quite the landmark in this flat prairie land and can be seen for quite some distance. It is completely unweathered, apart from being fractured by frost action over the years.

The site was declared a Provincial Historic Site back in the 1970’s and has been protected ever since. There is a parking area just off the highway where you will also find washrooms. There are steps and a wheelchair ramp leading down to a long pathway which leads to the rock itself. The pathway goes all the way around the rock and there are signs telling you to keep off the rocks. However, when we were there, two idiots had decided to ignore the signs, the fence and the obvious fact it is a precious site and climbed to the top. Not only were they violating the rules, they were ruining other peoples enjoyment of the rock and their photo opportunities. 

Looking at the rock it has many colours within it, from the grey and white, to orange and purple. These are layers of sediment that were formed between 600 million and 520 million years ago.

It is sometimes claimed that this is the biggest glacial erratic in the world, but it is far from that. In fact there is another near Cooking Lake Alberta which covers 10 sq km (4 sq miles). 

The word Okotoks which is also the name of the neighbouring town comes from the Blackfoot First Nations word for rock. There is a fable which comes from the ancient Blackfoot tribes of how the rock came to be split down the middle. 

“One hot summer day, Napi, the supernatural trickster of the Blackfoot peoples, rested on the rock because the day was warm and he was tired. He spread his robe on the rock, telling the rock to keep the robe in return for letting Napi rest there. Suddenly, the weather changed and Napi became cold as the wind whistled and the rain fell. Napi asked the rock to return his robe, but the rock refused. Napi got mad and just took the clothing. As he strolled away, he heard a loud noise and turning, he saw the rock was rolling after him. Napi ran for his life. The deer, the bison and the pronghorn sheep were Napi’s friends, and they tried to stop the rock by running in front of it. The rock rolled over them. Napi’s last chance was to call on the bats for help. Fortunately, they did better than their hoofed neighbours did, and by diving at the rock and colliding with it, one of them finally hit the rock just right and it broke into two pieces.”

Hopefully, not too many people will be idiots and completely ignore the no climbing rules and this magnificent monolith will be around for a few more million years.