The following is lightly edited from notes written last week, as I travelled westward on a flight from Fredericton to Toronto.
Across northern Maine and southern Québec, those ever-changing landforms are ghosts and memories. We cannot say that the Earth remembers everything that has ever happened to its surface – it has forgotten far more than it remembers, but it remembers a lot.
Every one of those features below us has a memory to tell, the story of how it was formed and how it changed through time – some of them are rich memories, full of detail and arc of story. Others are faded wraiths: you might just make them out if you look at them out of the corner of your eye, but they disappear when looked at straight on or in bright sunlight. Perhaps the dark arts of remote sensing, isotope analysis, and X-ray diffraction will divine their stories, but they hide their secrets deeply.
So many features, and so many of them are scars. Earth has had a long history of damage and injury – some of the injuries have come from outside, but some have been self-inflicted. Poor thing, our old Earth. We need to understand it better and treat it far better.
Walking with my brother earlier today, we compared injuries and war wounds – a chronically sore ankle here, an arthritic hip there. We commented that the human body might appear to heal, but it still carries the scars and damage within itself. That damage can rear up and reveal itself at some later date – if we had known what we know now, we would have been more careful decades ago when we hurt ourselves.
Earth is like that, too: many of its scars are not obvious to most of us. Those Appalachians we just passed over are one such scar – they tell us how tectonic plates crashed together oh so many years ago (starting about 480 million, actually), when Laurentia, the ancestral heart of North America, began to push into the crust of the ancient Iapetus Ocean (the continuation of this would eventually lead to the formation of Pangaea, as Laurentia pushed into northern Africa). In the process, Earth’s crust was buckled and pushed up into mountain ranges that, at their highest, may have been as tall as the Himalayas are now. Even Mount Katahdin, at a full mile high (including the cairn on top), is just a low remnant of those mountains. What happened to them? Earth may have self-harmed through plate tectonics, but it has been self-healing ever since through the use of weathering and erosion.
Earth started self-harming early on, apparently as a result of poorly resolved heat issues deep within. Plate tectonics began billions of years ago. The plates slowly move from one self-inflicted scar to another; the new crust rises at spreading centres (divergent boundaries) such as the mid-Atlantic Ridge, and crust is subducted and melted at convergent plate boundaries such as that along the Aleutian Islands. The scars are long and jagged, extending all around the planet’s face.
You might argue that Earth is not really self-harming, that plate tectonics is nature’s course, and just the way a planet has to be. But other terrestrial planets aren’t like this. They have managed to grow up without plate tectonics (like Mars?), or they may have experimented with plate tectonics in their early years (like Venus), but later outgrew this juvenile deviance.
And sure, Earth self-harms, but at least that self-harm prevents it from showing many scars of external violence, unlike the Moon and Mars. All these bodies have been bombarded by meteorites, comets, and other space debris, most notably in their formative years – they all had a tough childhood. Earth’s self-harming may have allowed it to overcome that childhood damage – the scarring from plate tectonics effectively hides most of the pitting and damage from that external violence, except for a few places like the Manicouagan crater (which isn’t all that far to the northeast of us here).
Now we are out over the flat Saint Lawrence Lowlands. We could consider this sort of sediment-covered plain as being a “fully healed” patch of the Earth. The sediment has accumulated on and off over the past 500 million years or so. It blankets and hides the far less regular terrain beneath, including Logan’s Line where Appalachia and the Canadian Shield butt up against one another. Even below all that sediment is a scar that has never quite healed, as evidenced by the earthquakes that have occasionally struck Québec during the past few hundred years.
But wait. I can see some fresh wounds down there. Erosion never sleeps, and those valley sediments, even the relatively recent ones deposited under the Champlain Sea some 10,000-13,000 years ago, are cut by fresh narrow rivers that knife through the surface and carry away the clay and soil.
Flying over Montreal, we see some of the most recent of Earth’s cuts and scars. But these are not self-caused; rather, they come from a parasitic infestation. The deep slicing of the St. Lawrence Seaway, the piling of stone on the side of Mount Royal, the piercings constituted by the Lafontaine Tunnel: these are not Earth’s own doing.
Will Earth’s scars and damage ever heal? With enough weathering and erosion, all those hills would be flattened, rock fragments and clay would be transported away by rivers, and the entire surface of the planet would be a nearly level plain, probably located somewhere below sea level. But fortunately for all life, that won’t happen, because there is no evidence that Earth will ever cease self-harming. Even as I write this it is creating new crust along the ocean ridges, and pushing the Himalayas just a little bit higher. We can rest secure in the knowledge that tectonism never sleeps.
© Graham Young, 2016
Those of us who study the ecology of long-extinct marine creatures have to work from clues: the morphologies of the fossilized organisms, the character of the enclosing sediment, and the preserved spatial relationships between fossils in bedrock. It is always pleasing to see modern examples that support our interpretations of ancient life. These photos from the shore of Passamaquoddy Bay show some very nice examples of the way in which many organisms need solid substrates.
In some sedimentary rocks formed on muddy or sandy seafloors, such as Manitoba’s burrow-mottled Ordovician carbonates, we often see fossil corals that had grown on top of other corals, corals that had grown on top of stromatoporoid sponges, and sponges that had grown on corals. In interpreting these we generally state that the distribution of the fossils was governed largely by the rarity of hard substrate. If the seafloor was covered with firm sediment, then the coral or sponge could have grown directly there. But if the seafloor was composed of soft or shifting sediment, then an organism there could not remain in a stable position, and it was only those that found firmer substrates that were able to survive. Thus, we see the corals and sponges that had grown on other corals and sponges, as those were the only hard surfaces around (whether the overgrown creatures were alive or dead at the time is a whole other avenue of inquiry).
World Water Day, 2016
As World Water Day draws to a close, here are a few images illustrating a fraction of Canada’s immense store of fresh water. World Water Day brings to the fore humanity’s concerns about fresh water, health, and environment. Canadians need to be far more aware that Canada holds about 20% of the planet’s freshwater resources; this water is critical not only to our population and industries, and to our marvellous wilderness and ecosystems, but also to the global environment.
These photos were all taken during my travels in the past year.
. . . we have been very busy at the Museum for the past few months, and much of this busy-ness has been associated with preparing exhibits about a spectacular Cretaceous pliosaur (plesiosaur) skull that we acquired a couple of years ago. Much of my own work on the project has been more on the “paper” side of things (researching and writing the exhibit panels, working on grant proposals and budgets), but other staff at the Museum have been doing some fantastic hands-on work, and you might be interested to look at the story and photos of the skeleton mount work on my museum page.
Fieldwork in the Hudson Bay Lowlands, August 15, 2015
A grey, chilly morning at the Churchill Northern Studies Centre had us considering the weather. This was to be the last of our three “helicopter days” for 2015, so we really wanted to be out there over the horizon. But the weather forecast was not particularly promising (or rather it promised things that we’d rather it didn’t), and mist, wind, and damp were certainly evident. Still, the visibility wasn’t too bad here near the sea, and anyway, weather forecasts in the Hudson Bay Lowlands are frequently far from accurate.
The helicopter pilots, both with decades of experience, seemed quite cheerful and ready to go, so who were we to argue? So we buckled in and set off for our sites, some tens of kilometres inland on the bank of the Churchill River. As shown in the photos below, the conditions we met en route were sometimes almost artistically misty, but always acceptable for flight. And as we arrived at the first site the fog and rain began to depart, revealing a day that became, by lunchtime, quite splendid for fieldwork.
Churchill, Manitoba: August 25th, 2015
Down the road there is always something new to see. Even on a road you have travelled before, there will be unseen treasures, just waiting by the roadside to be discovered.
At the Churchill Northern Studies Centre (CNSC), our 2015 field season was complete. It had been a fantastic two weeks, possibly the best ever, but now it was done. The samples had all been wrapped, bagged, boxed, and palletized. Together with the field gear they awaited shipping in the dark of the former CNSC building. Our clothes, boots, and rain gear had been stuffed into packs and duffles, we had cleared out “our” vehicle, and we had tidied all of the lab spaces we had temporarily occupied.
We really had nothing left to do on this clear morning, which felt warm yet carried within the first hints of an early-arriving northern autumn. Nothing to do but put on our walking shoes, gather up cameras, sign out a shotgun, and take a wander down the launch road. Plenty of time to contemplate this beautiful land, to examine in detail a stretch of gravel that we normally passed at what passes for highway speed around Churchill. And, of course, plenty of time to feed a bit more blood to those Churchill mosquitoes.
Grand Manan Island: July, 2015
Jellyfish are known for being short-lived. Not far from a jelly bloom where uncountable medusae swim and pulse, you might expect to find numbers of dead and dying jellyfish. In the case of the jelly bloom in North Head harbour this past summer, weakened and dying jellies were washing up nearby along the shore of Flagg’s Cove. On one unusually warm Saturday afternoon, so warm that it was pleasant to wade in the Bay of Fundy, I spent some time documenting the breakdown of white cross jellies, Staurophora mertensii. The images below show the generalized series of stages, from the living jelly to its near disappearance (this transition doesn’t take long!). As usual, my long-suffering family was remarkably tolerant of my slightly obsessive jelly observing.
Why should I want to know what happens to white cross jellies when they die and decompose? For several years, I have been working on a detailed study of fossil jellyfish from the William Lake site in central Manitoba. Those jellies, which were alive some 445 million years ago, were hydromedusan cnidarians very similar to Staurophora. By carefully examining and documenting the jellies at Flagg’s Cove, I improved my understanding of the fossil jellies at William Lake, and of the processes they had passed through during fossilization. This will contribute to the interpretation of those fossils, as we work toward their scientific publication.