Erratic Boulders
Tuesday, 29th July 2008 by Alex Turnbull
An erratic boulder is, simply enough, a piece of rock that doesn't originate from the place where it is found. When these errant boulders are the size of houses however, they take a little more explaining.
The city of White Rock, British Columbia, gets its name from a large white erratic that seems completely out of place sitting on the shore of Semiahmoo Bay.
In fact, boulders like this one were carried to their current locations by glacial ice, often over hundreds of kilometres. Geologists have suggested that landslides or rockfalls initially dropped the rocks on top of glaciers, which then carried the rocks along with them on their journeys. When the ice melted, the erratics were unceremoniously deposited wherever we find them today.
The largest glacial erratic identified so far is Big Rock, near Okotoks, Alberta. Measuring 41 m by 18 m and standing 9 m high, this massive quartzite boulder weighs around 16,500 tonnes.
Geologists believe that Big Rock made its epic journey between 12,000 and 18,000 years ago - all the way from Mount Edith Cavell in Jasper National Park - a journey distance of nearly 500 km.
There's more about Glacial erratics, White Rock, and Big Rock at Wikipedia.
About the author
Alex has decided that his title will be Senior Vice President of Stuff.
I live near White Rock, and my aunt is the City Manager of Okotokos, which is just outside of Calgary, where my family is from and I was born; so I found this interesting as I had never heard of Big Rock. I found this page that tells more about the rock, including the fact that the Blackfoot name for rock is “okatok”. I guess I now know where Okotokos got it’s name.
I remember seeing one of those erratics in Denmark (something like 15 years ago), and it was quite big. I’m pretty sure it’s the one described in this Google Earth Community thread: http://bbs.keyhole.com/ubb/showthreaded.php?Cat=0&Number=1192512&page=&fpart=&vc=1 …and some ground-level pics too (both sites in danish so I don’t understand what’s written…): http://klatresteder.dk/klatrested.php?id=55 http://www.fynhistorie.dk/node/4327
@Gregg ha, and I lived in Bellingham, and had no idea why White Rock was named such!
i actually saw big rock on a study abroad class/trip in western canada that i went on for my geography degree in college. this thing is HUGE, trust me. it is unbelievable. its pretty crazy that its actually on this site, haha.
Lol, I go here like atleast 3 times every month. I live in this general area XD