The Tale of Salt Spring Rocks
If there is one thing that humankind will never truly wrap its mind around, it is the concept of time. Sometimes minutes can feel like a lifetime, and yet before we know it, years have passed. We have no real scheme for comparing our clocks and our lifetimes to the age of the Earth. To think that the Earth has been blasting away cliffs and churning up mountains from deep below its crust for billions of years, constantly, incrementally changing shorelines, bending rock and even moving continents, is something we will never see with our own eyes. All we have to witness the geological passage of time is the evidence of its effects.
On Wednesday, the 23rd of May, Geology 12 took a field trip to Salt Spring Island, to see with our own eyes a close-to-home example of the powers of the Earth. The class loaded a bus around 10AM to catch a ferry over to the island, and then spent a day examining the layers of the Earth. Thanks to the miracle of modern road building, and our habit of using dynamite to blast things out of the way, the innards of hillsides lay open to the class. The bus pulled up as close as it could, and the class milled around the rock face, taking measurements and estimating what type of crustal deformation had caused the sedimentary rock layers to bend.
To really understand the process, one would have to take Mr. Doehler’s Geology 12 class, as there is a fair amount of theory behind it. Suffice it to say, as rock layers are created, forces within the Earth can bend and deform them over periods of time. Ways of seeing this, other than the sometimes clear effect of layering, is to take measurements like the strike and dip of the rocks, a procedure which requires geologists to use compasses, a skill which seems to have skipped today’s generation.
A group of students asked Mr. Doehler what the equivalent amount of time would be for the Earth to have eroded this area of rock compared to what humans had done. The answer was that in a simple matter of months or years, humans had shaped the Earth in a way that would have taken natural processes centuries.
After scampering around the shale and mudstone cliffs, adding our own transitory footprint to the erosion, the class moved to Vesuvius beach to admire a cliff had that been flipped on its side. While layers would have been deposited horizontally, now the rock layers were on their sides, barring themselves along the beach. As we walked along, taking notes on various anomalies (faults, and fossils of long extinct clams, etc.) with every pace we crossed thousands of years of geological time, and the concept was staggering. Huge expanses of time lay below each foot, and they had shaped the beach that the class was lunching on.
There are numerous real-life applications for what Geology teaches us. The location of certain types of minerals may lead to resources like oil or rare metals. While the class was not discovering the next oil sands, it was learning a little bit more about the environment and how it evolves. It was a history class in which the Earth was telling its story in its own way.
< Leaders 11