Introduction
Lake Superior. The greatest of the Great Lakes. It is the largest freshwater lake in the world by surface area, at 82,000 km2, and the third largest by volume. The Anishnaabe, who have inhabited the area for over 500 years, know Superior as gichigami, which translates to “big or great body of water” (Tarlach, 2022). Superior is entrenched in art and popular culture – think Group of Seven and Gordon Lightfoot – and is the head of the Great Lakes/St Lawrence Seaway that connects Lake Superior to the Atlantic Ocean. But the facts don’t prepare you for the power of the lake and the beauty of the surrounding landscape. For that, you need to appreciate Superior on the water.
“What are you doing this weekend? Want to come on the Denison Falls trip and tell us about rocks?” In August of this year I bought a brand-new kayak, took it for a test paddle, and promptly fell out of it. It was clear that I needed to brush up my skills, and what better way than to spend a couple of days at Naturally Superior Adventures at the Michipicoten River mouth near Wawa, Ontario. My intention had been to book a 2-day basic kayaking skills course. What actually happened was that I ended up on a 5-day, 4-night paddling and camping trip to Denison Falls to provide geological interpretation, departing in three days. After a few minutes of contemplation, and a day of shopping to lay in some camping supplies, I packed my car and embarked upon the 9-hour drive to Michipicoten.
Lake Superior itself is quite young, having formed about 10,000 years ago at the end of the last ice age, as the glaciers melted and retreated northwards. The story of Superior’s formation, however, is one that encompasses 2.7 billion years, more than half of all of Earth’s history. It is a story of three acts: the formation of the Superior Province, tearing it all apart, and the geologically recent modification by glaciers. It’s also a story best told, so it turns out, from a kayak.
Day Zero
I arrived at Naturally Superior on a windy, stormy, Sunday morning. The waves crashed upon the rocks around the lodge and created a nasty-looking maelstrom at the mouth of the Michipicoten River. Given my lack of kayaking experience, and recent poor performance in the very calm and very small lake at the end of my road I wasn’t feeling particularly confident in my ability to survive the next five days. Nonetheless, I unpacked my gear into my beachfront Goose Dome, changed into my paddling clothes, and prepared for an afternoon of skills refreshers and wet exits. I met my co-paddlers, and Sophie and Oliver, our guides for the next five days, then I plopped into my kayak (turns out I had been doing it wrong all these years) and paddled up the river towards Mission Falls.
According to Oliver a paddler should be one with their kayak, like a Centaur, snugged into the cockpit. This provides contact and control, and my kayak felt quite stable as I paddled up the river to test my skills and confirm to all concerned that I could indeed tackle five days of paddling on what can often be troubled waters. Snugging into one’s cockpit, however, does make for a more challenging wet exit than my more open, recreational kayak. All participants on the trip had to demonstrate that we could get out of our boats should be get dumped upside down, and that we could get back in. Gravity helped with the getting out, although not without some very colourful bruises on my thighs, but getting back in was very inelegant, and I am grateful that there is no photographic evidence of my lack of grace. I did, however clumsily, pass the “wet exit” requirement, and was thus ready for departure the next morning.
Day One – Michipicoten River to McCoy’s Harbour
The day dawned clear and calm – phew! – with nary a wave in sight. We started our morning with a hearty breakfast at the lodge then packed the kayaks, ditched everything we decided at the last minute would be superfluous, and launched from the beach. Our intent for day one was to paddle from the Michipicoten River to McCoy’s Harbour, a distance of about 19 km, which was about three times further than I had ever paddled previously. The weather forecast for later in the week was not great, so the aim was to get to Dog River and Denison Falls as soon as possible, in case we needed to return early. Our first task was to cross the 4-ish kilometres from Michipicoten Bay to Perkwakwia Point, then make our way to our campsite along the coast, admiring the rocks along the way.
The Wawa terrane – part of the Superior Province of the Canadian Shield – is a granite-greenstone belt that formed through convergent plate tectonics about 2.7 billion years ago. In the Michipicoten River area the rocks are predominantly basaltic pillow lavas, formed when mafic magma erupted beneath the ocean in a submarine volcanic arc and cooled rapidly. The pillows were deformed during ongoing convergence and the formation of the terrane. As we moved westward the geology changed to spectacular conglomerates, some highly deformed, and none of which I managed to photograph for fear of losing my phone in the icy and rough waters of Lake Superior. Further west the geology again changed to felsic intrusive rocks – tonalite, granodiorite, and granite – and it was upon these rocks that we set up camp for the night.
McCoy’s Harbour campsite is a tombolo – an island connected to the mainland by a sand spit. Campers can set up on the site facing the setting sun or the rising sun and dine on a chunk of 2.7-billion-year-old granite, worn smooth by the actions of glaciers and pounding waves. By the time we arrived at McCoy’s having paddled into the wind for much of the day I was exhausted! We set up our tents and got unpacked, then managed to squeak in a swim while our lovely guides were preparing dinner. The lake was freezing, but it was a smoking hot day, especially in a wetsuit, which I am going to ditch, so it was a refreshing end to a taxing day. I don’t recall what we had for dinner on the first night. I know it was delicious, as were all our meals, but I was done in for the day. My arms were tired (poor paddling technique), I was emotionally worn out (I stressed about my competence and abilities WAY too much), and I was full, so I crawled into my sleeping bag in my tent pitched on the beach and passed out.
Day Two – McCoy’s Harbour to Dog River
Tuesday morning dawned warm and slightly overcast. After a much better sleep in a tent than I expected, I woke just before 6 am and lay in my sleeping bag until the sun rose over the beach and the coffee was ready. Our wonderful guides cooked breakfast – Shakshuka. Delicious! – then we packed our boats and headed west towards Dog Harbour and Denison Falls
Much calmer weather made rock watching easier, and as we paddled west the geology changed from the granites and tonalites of last night’s campsite to felsic volcaniclastic tuffs crosscut by dolerite dikes. We made it to Dog River by lunchtime after an easy 7km paddle then set up camp at the river mouth in advance of a hike to Denison Falls in the afternoon.
Denison Falls and the Dog River are within Nimoosh Provincial Park, the name of which is derived from the Ojibway word for “dog”. Geology maps label the river the University River, an outdated designation apparently given to it by students and faculty of Denison University who were oblivious to the long-lived and deep connection to the land of the Indigenous peoples of the area.
We accessed the falls via a short but rugged hike upriver from the campsite, on a narrow trail through mostly coniferous forest, catching glimpses of the river below along the way. The trail opens up to a glacially polished outcrop of felsic tuff crosscut by thin diabase dikes, and the falls are just beyond, cascading over metaconglomerate and metavolcanic rocks. The upper falls can only be observed by climbing up a cliff, which I regretfully skipped that day. Should have done it. Chickened out. Nonetheless, the lower falls were still very pretty, even at very low water flow, which is what we encountered, and the rope ladder nerdily defined a contact between conglomerate and mafic volcanic rocks.
Day Three – Dog River to McCoy’s Harbour
Geologically the Wawa terrane is complex, and has been folded, faulted, intruded by granitoid magma, and metamorphosed to greenschist facies. The Michipicoten Belt, through which we were travelling on this excursion, is interpreted to reflect a convergent margin like the modern Taupo-Kermadec-Tonga volcanic zone in New Zealand (Sylvester, Attoh, & Schulz, 1986) and is characterized by bimodal basaltic and felsic volcanism with associated clastic sedimentary rocks that Sylvester et al. (1986) interpret to represent a subduction zone that varied laterally from an immature island arc on oceanic crust to a more mature, continental volcanic arc.
The Michipicoten greenstone belt is distinctive in that it has very well-preserved felsic volcaniclastic rocks not as evident elsewhere in the Canadian Shield, and Dog River is an excellent place to see them. On Wednesday morning I spent a couple of hours looking at the outcrops on the eastern edge of the beach, while others paddled further west for a scenic excursion.
Narrow (30-50 cm) subparallel mafic dikes crosscut the volcaniclastic rocks. They are foliated, indicating emplacement during the formation of the Wawa terrane, and are therefore not the younger dikes of the Mid-Continent Rift event, which formed the basin now occupied by Lake Superior. The lake was calm and clear on this morning and afforded a spectacular view of the rocks extending beneath the water. As we departed Dog River on Wednesday afternoon we stopped for a geology lesson at the outcropping rocks. A first for me – teaching from a kayak!
As we headed back to McCoy’s Harbour on Wednesday afternoon we transitioned back into the foliated basalts and got to observe one of Lake Superior’s more unique and quirky plant species.
Encrusted Saxifrage (Saxifraga paniculata) is an arctic disjunct – an arctic plant that typically grows further north but has found a unique habitat in the rocks and climate of Lake Superior’s north shore. Saxifrage is a calciphile, that is, it prefers calcium-rich rocks and soils, which are not generally afforded by basaltic rocks. Encrusted Saxifrage also grows on basaltic rocks at Pukaskwa National Park, further west along the Lake Superior coastline. Geologist Andy Fyon (2022) observed that Saxifrage is more abundant on highly deformed basalt and concluded that deformation liberated calcium from plagioclase and pyroxene – essential rock-forming minerals that characterize basalt – providing the necessary nutrients for Encrusted Saxifrage to grow.
We arrived at McCoy’s Harbour in the early afternoon, and after setting up camp it was time for a swim! Superior is cold but the weather all week was hot and sunny (I had ditched my wetsuit by Tuesday), so a refreshing dip was a welcome end to a day of paddling. As the sun set over the beach we prepared for a longer day of paddling on Thursday to Dore Bay.
Day Four – McCoy’s Harbour to Doré Bay
Thursday again dawned warm and sunny, and after breakfast we packed our kayaks (it’s amazing how much you can stuff in those things!) and headed west towards rocks that provided evidence of the birth of Lake Superior.
Although the Superior Province is ancient, the lake is only around 10,000 years old. Its presence, however, is due to a combination of geologic events that occurred over a billion years ago, and much more recently, between 2.6 million and 11,700 years ago.
About 1.1 billion years ago tectonic forces began tearing the Canadian Shield apart in a process called mid-continent rifting. As the continent separated, magma from deep within the earth rose towards the surface, erupting to form basalt lava flows and intruding the much older Wawa terrane to form diabase dikes and sills.
The rifting formed a three-armed basin that filled with lava, and with sediments eroding from the surrounding Canadian Shield. Then, the rifting stopped. Had it not, the rift would have opened to become an ocean in the same way the Atlantic Ocean formed.
The basaltic and sedimentary rocks that filled the basin were much softer and more susceptible to erosion than the surrounding rocks. During the last ice age these much softer rocks were scoured away leaving behind a depression that filled with meltwater to form Lake Superior.
The dolerite dikes that record evidence of the mid-continent rift (MCR) event feature prominently along the coastline from McCoy’s Harbour, their dark colour prominent against the pink of the granite country rock. The water was so still and clear on that day that I could see where the dikes extended into the lake, and it was a fun perspective to paddle over them.
As we got closer to Doré Bay the rocks changed to spectacular deformed and undeformed pebble to boulder conglomerates of the Doré formation. These are much older rocks and are part of the Wawa Terrane. The clasts are dominantly felsic intrusive (granite) and extrusive (rhyodacite) rocks and are interpreted to reflect erosion of the volcanic arc during subduction (Sylvester, Attoh, & Schulz, 1986). Fortunately, the lake was much calmer than when we passed the same rocks on Monday, so I got to see them up close and personal, and take some photographs!
Doré Bay was our final campsite so before setting up camp for the evening we paddled up to the river mouth, then dived in for a final swim. The forecast was for rain and an easterly (of course!) wind for Friday morning, so the intent was to pack and leave early, and arrive back at Naturally Superior around lunch time.
As Sophie and Oliver prepared yet another delicious dinner, and breakfast for the following morning so that we could get away earlier, we all reflected on the amazing four days we had spent paddling the lake, and the truly spectacular weather (unheard of, apparently), that graced our trip.
Day Five – Doré Bay to Michipicoten River
As predicted, Friday dawned wet, and I awoke to the sound of rain, after a restless night disturbed by a creature snuffling round my tent. It sounded like a sasquatch but was probably the red squirrel we had seen around the campsite the night before. Fuelled by chia pudding for breakfast (honestly, the food was amazing – I really need to up my camp cooking game) we braced for the weather and pointed our kayaks towards the west.
We expected rain and a fairly significant head wind, but the weather gods were again smiling on our final day. Although overcast, the rain stopped by the time we broke camp and the forecast southeasterly didn’t pack quite the punch we expected. Nonetheless, we gathered at Perkwakwia Point to make the final push across Michipicoten Harbour as a team. As we passed through the river mouth at Naturally Superior the lunch bell rang 12 o’clock, and after five amazing days on the Lake we were back.
All that was left to do was unpack the kayaks, return the borrowed gear, and eat one final lunch on the beach, before visiting the gift and gear shop (excellent, highly recommend), then departing for home and the prospect of a hot shower for the first time in a week.
This trip was not something I ever expected to do. Paddling Lake Superior, while theoretically appealing, seemed daunting, and well out of my reach in terms of skills and fitness, but when the opportunity arose it seemed like the perfect opportunity to test my limits, and look at some amazing rocks along the way. I got to share some knowledge with a great group of people who were willing to engage in my nerdy conversations, I learned some necessary paddle skills (no tipping out of my kayak now) and realized that I am quite capable of doing hard things. There is no stopping in the middle of the world’s largest lake when your arms get tired!
Naturally Superior Adventures runs the Denison Falls trip annually, so check it out for 2025. I may just see you there!
References
Fyon, A. (2022, August 12). Geology and Encrusted Saxifrage. Ontario Beneath Our Feet: https://www.ontariobeneathourfeet.com/geology-and-plants#/geology-and-encrusted-saxifrage
Natural Resources Canada and Ontario Geological Survey. (2015). Thunder Bay: Geology of the Lakehead region: Geotours Northern Ontario Series. https://files.ontario.ca/ndmnrf-geotours-3/ndmnrf-geotours-thunder-bay-en-2021-12-13.pdf
Sylvester, P. J., Attoh, K., & Schulz, K. J. (1986). Tectonic setting of late Archean volcanism in the Michipicoten (Wawa) greenstone belt, Ontario. Canadian Journal of Earth Sciences, 24(6), 1120-1134.
Tarlach, G. (2022, April 27). Are the Great Lakes really inland seas? Atlas Obscura: https://www.atlasobscura.com/articles/great-lakes-inland-seas
Earth Research 
Great summary of your trip! What an amazing thing to be able to learn (or refine) a new skill while also teaching others something new, too. Very cool.
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