Shale a Lot!
When I visited river banks, lake shores, roadsides, and random fields, if there was a rock I probably picked it up, and about half the time I took it home (the prettier the better, but I wasn’t too discerning). Family road trips in the summer inevitably ended with me sacrificing my legroom for bags bulging with rocks I collected, and at least once I paddled a canoe with my pockets stuffed with rocks; it was a very lucky thing that I didn’t fall in.
Of course, when I came to work at the CFDC last year I was haunted by rocks; specifically shale. Because of course.
As a field technician you can probably guess my life at work revolved around shale and fossils. I looked for fossils (in shale), lead tours to look for fossils (yup, in shale), and of course, removed overburden (crushed up shale already looked through for fossils).
To keep our dig sites clean and productive, the overburden must be raked, shoveled, and carted away. For some reason, last year our time clearing overburden happened to be on the absolute hottest, sunniest days of the season. Sometimes the wheelbarrow broke; sometimes human error dumped a particularly heavy load 5 feet from where it began and you could hear a collective groan.
Although fun you can bet it was always hard work.
However, while in the field I got to do something I’d never done, despite my large rock collection: I finally learned about rocks. What is shale made of? Where did it come from? What minerals do we find in our shale? How old is it, does it all look the same, what does it taste like? Now I know, and am proud to report that our shale is made of silt from the bottom of the Western Interior Seaway, often with a fair amount of a mineral called gypsum. Here in Manitoba the shale is 80 million years old, and it’s not all the same: some is very clumpy, while others flat and layered. Some is well known for preserving fossils, while others almost never will. Oh, and of course, it tastes exactly how you would expect shale to taste: like mud and dust.
Allow me to explain why I know this. Part of identifying certain shales comes down to the exact texture: is it gritty or silty? At some point a long time ago a very intelligent geologist decided the proper way to test this is to rub a piece, fresh from the ground, against one’s teeth: Does it feel like sandpaper on your teeth? It’s gritty. Does it feel like soap on your teeth? It’s silty. Unfortunately, as every field technician discovers, the taste stays with you for a long time no matter how many times you brush your teeth!
Days after one particular day in the field I asked friends and family if they knew that about shale. I asked them to guess how I came to learn it. They all responded with a mix of pity and what I’d like to believe was respect: “You licked a rock, didn’t you?”
I had not, in fact, licked a rock. I had, of course, scraped it against my teeth.
While undergoing such adventures as shoveling shale and putting it in my mouth, I felt extremely lucky to be experiencing the province and area I’ve lived all my life in such a new, unique way. While my peers got summer jobs where they were trapped inside all day mine had me outside all day! I got to hike to outcrops, uncover fossils that had laid untouched for millions of years, and to learn some of the most fascinating Manitoba history.
So often as a student I’ve memorized things simply because I was told they would be on the test, not because I was truly excited about the information. Summer is the perfect time to remember how fun it is to learn about the things that are truly interesting. While this year may have been pretty rocky so far, my challenge to everyone is to investigate something they may have overlooked until now. Bonus points if it can be done with a trip to a museum.
And remember! Don’t lick rocks unless you absolutely must.
-Tessa, 2019 – 2020 Summer Crew