Thursday, April 16, 2015

Rock Post: The Sea to Sky Wall in Vancouver Airport

Have you been to the Vancouver Airport?  If you have, you've probably walked past this ginormous feature below.  Have you ever wandered over and read the little sign there about this wall?  Probably not, unless you're 1) bored out of your face (which, it's an airport, you're either bored out of your face or stressed out and running to catch a plane - there is nothing in between in an airport), or 2) a geologist.  And especially when you're both of these things.

Sea to Sky Wall in Vancouver Airport
Centre panel with waterfall.  The rock here is the Garbaldi Golden Granite (actually granodiorite).
I love this feature.  It's two stories high at least and has a lovely waterfall in the middle, which gives the surrounding air a lovely ozone-y smell.  It's as peaceful a place as you're going to find in a busy airport like this one.  And it has rocks, so bonus!

So as an extremely bored geo, I thought I'd share it with you.

Sea to Sky Wall in Vancouver Airport
One of the two side panels (and the entrance to the Maple Leaf Lounge).  The rock here is the columns of Rhyolite.
I'm not going to upload a photo of the write up since there was too much glare, so I've transcribed it below:


Shaped by the earth's heaving crust, fiery volanoes, and colliding terranes, the rocks and mountains of British Columbia tell a story over 200 million years old.  

Much of our mountainous west coast is formed of granite, an igneous rock.  Here, molten magma crystallized far below the earth's surface to become one of the largest masses of granite in the world.  North of Vancouver, Mount Garibaldi rose through the surrounding ice in a series of volcanic eruptions about 20,000 years ago, its granitic cone created by the cooling lava.

Displayed on this wall are two local varieties of igneous rock.  The ways in which they evolved resulted in their different grain sizes, crystal shapes, mineral content, and colours.  Both types of rock were quarried by Garbaldi Granite from unique deposits in the Squamish Valley, located near the Sea-to-Sky highway between Vancouver and Whistler.

Centre panel with waterfall:
Garbaldi Golden Granite is a coarse-grained rock known as granodiorite.  Its large crystals of feldspar and quartz were created during the slow cooling of magma within the earth.  The unusual golden colour of this granite developed over thousands of years, as iron-rich soils leached through its crevices.  The rock is quarried without explosives; a wedging system is used instead to avoid cracks and damage.

Other [two] panels:
Rhyolite is similar in composition to granite, although it is more finely textured.  It occurs naturally in 6-to-8 sided columns - the result of lava cooling rapidly at the earth's surface after a volcanic explosion.  The columns are easily quarried by machine from their loose deposits.

I have to note, before I continue, that granite and granodiorite are entirely different rocks based on mineral content, so I'm a little annoyed with the description above.  But oh well, granodiorite forms in a similar manner, it's only different chemical compositions of the magma itself that determines the rock type that forms.  LET IT GO HEATHER.

Sea to Sky Wall in Vancouver Airport
Close up of granodiorite, bright pink pen for scale.
Here's a close up of the granodiorite. It was difficult to photograph, since the yellow colour they noted actually masks to individual crystals.  I found one piece that was cleaner, so you can sort of see the coarse white feldspar, the light-grey quartz, and the smaller-grained, dark coloured mafic minerals (usually dark coloured, denser minerals that are usually the first minerals to crystallize from the cooling magma as they have a higher melting temperature).

Sea to Sky Wall in Vancouver Airport
Rhyolite columns.  Bright pink pen for scale.
Here, you can see the tall, narrow columns they were talking about in the rhyolite wall.  I actually thought that these columns only formed in another rock type - basalt.  We have columnar basalt in Whitehorse - maybe I'll write up a post about them this summer.

Sea to Sky Wall in Vancouver Airport
Close up of the rhyolite.  Bright pink pen for scale (you sick of me stating the obvious yet?  Sorry but too bad, I'm stoked that I actually remembered to include a scale in my rock photos!)
Here's a close up of the rhyolite.  I know it looks similar to the granodiorite, but it's actually very fine-grained so you can't really see any individual crystals, and those dark bits that look like the mafic minerals in the granodiorite?  Not actually minerals.  They're gas bubbles called vesicles, that formed when the magma got closer to surface and the gas within the magma that was dissolved at depth, started to separate out and form bubbles.  Pretty cool, eh?

Travelling sock wip
Cruising along on my sock!
And for something different, this is my travel project.  I'm making myself a pair of socks!  I wonder if I can finish this one before i get to Winnipeg?  I only have another 10 hours of travel...

My view of Vancouver while writing this post.  You're very pretty, Vancouver.  Someday I'll visit more of you than your airport.

1 comment:

  1. Hi Heather,

    Good post about the Sea To Sky wall. It was my favorite place at YVR, but located in a place where you're likely to hurry by. I'm a geologist too and it reminds me of when I was working as an exploration geologist and they would pay for my trips to and from camp every few weeks - I was always going through YVR. That was during the mining and exploration boom, around 2010, before economic problems in China caused problems in Canada. I hope things get better and I get to visit Vancouver again sometime. Thanks for the article