by D'Arcy Hutton
Why, hello there geologic history!
Time travel. I think about it a lot. And when I do, the distant past feels so tangible. So present. I feel the same buoyant almost-vertigo I feel when swimming, goggled, in the clear waters of Lake Superior. There, I can peer down at vivid volkswagen-sized boulders, bright igneous rock with veins like butterscotch ripple, fifty feet below me. Far beyond my lung capacity, yet so close, separated only by a stone's throw expanse of something clear, airless, and cold, straight down. More like flying than swimming. The distant past feels like that: so vivid and close at hand, but just beyond my lung capacity.
Maybe it's not a coincidence that the elements of water and geology are the chosen metaphors for my relationship to history. It was through the concepts of landscape-level tracking in the Canadian Shield landscape of my home region that I began practicing that momentary switch in perspective.
Maybe it's not a coincidence that the elements of water and geology are the chosen metaphors for my relationship to history. It was through the concepts of landscape-level tracking in the Canadian Shield landscape of my home region that I began practicing that momentary switch in perspective.
Photo of the Eardley Escarpment by Beyondhue on Flickr. Thanks!
This is the Eardley Escarpment, where the Canadian Shield fizzles abruptly into the Ottawa River Valley. This photograph faces West; to the North, the landscape is rolling granite, pine/hemlock/maple forests, and lakes resting in the dimpled surface of the Shield. To the South, a flat and fertile floodplain. Imagine this landscape as a northern coastline of an extinct sea, a brackish inlet of the Atlantic ocean, the Laurentide ice sheet languishing just to the north. What are now wooded gullies embellishing the sloping grasslands of the Ottawa River Valley were cut as stream channels through the glacial beach.
The sea left behind sand plains, dunes, and pine barrens. Ancient drainage deltas trace this story beneath present-day forests, formed as the sea retreated. Ancient marine clay deposits today cradle swamps and peat bogs, and sometimes surprise small towns with sudden landslides.
The sea left behind sand plains, dunes, and pine barrens. Ancient drainage deltas trace this story beneath present-day forests, formed as the sea retreated. Ancient marine clay deposits today cradle swamps and peat bogs, and sometimes surprise small towns with sudden landslides.
glacial layer cake
Imagine the waters and hills replete with the beings of 10,000 years ago. What did it smell like? What did it sound like? The granite shoulders of the hills still harbour relic species like blunt-lobed woodsia (Woodsia obtuse) and Slender Moonwort (Botrychium lineare), and Three-Spined Stickleback (Gasterosteus aculeatus) still swim in the still freshwaters of Pink Lake.
moonwort diagram from http://en.wikisource.org/wiki/File:BB-0005_Botrychium_lunaria.png
The tracks of a time so alien -- and yet so recent in geologic terms -- still visible in the landscapes of my home throws my imagination back in time with incredible force. In those moments I can feel the cold, moisture-laden maritime wind, see the orders of life in the frigid brine of this extinct sea. I imagine harp seals, bearded seals, harbour seals, and arctic ringed seals zipping through the blue light beneath the ice, plump and self-contained. The presence of the Arctic ringed seal and the Bowhead whale indicate that the waters of the Champlain sea mimicked the present-day conditions of the Arctic Ocean. Their bones are still found in the Ottawa River Valley, telling us of a time when ice prevailed year-round. Beluga whales, harbour porpoises, humpback whales, and finback whales all filled the sea basin with their music and their movements.
Just over ten thousand years ago, the sea floor began to rise and shrug off the waters. This process, called isostatic rebound, was the land straightening up and stretching its shoulders after undergoing immense compression beneath two kilometres of ice for a hundred thousand years. Three hundred years later, the sea was gone.
I've read that blue jays are the main drivers behind the northward expansion of oak trees in the post-glacial species creep. Their snatching and stashing of acorns left some to germinate, thereby inching the species north. Well, not really inching: their expansion is thought to have proceeded at 400 yards per year. This reciprocal relationship selected for oaks that bore acorns of a manageable size for blue jay beaks. Among the rustling red oaks of the sun-drenched escarpment, it's easy to imagine myself standing on a scraped-clean landscape, the unobstructed norwesterlies damp and cold in my face, listening to the yells of the blue jays bringing life north.
Just over ten thousand years ago, the sea floor began to rise and shrug off the waters. This process, called isostatic rebound, was the land straightening up and stretching its shoulders after undergoing immense compression beneath two kilometres of ice for a hundred thousand years. Three hundred years later, the sea was gone.
I've read that blue jays are the main drivers behind the northward expansion of oak trees in the post-glacial species creep. Their snatching and stashing of acorns left some to germinate, thereby inching the species north. Well, not really inching: their expansion is thought to have proceeded at 400 yards per year. This reciprocal relationship selected for oaks that bore acorns of a manageable size for blue jay beaks. Among the rustling red oaks of the sun-drenched escarpment, it's easy to imagine myself standing on a scraped-clean landscape, the unobstructed norwesterlies damp and cold in my face, listening to the yells of the blue jays bringing life north.
RSS Feed