Parts of Northern Vancouver Island missed by last Ice Age — researchers

Researchers recovering a core from Little Woss Lake. Photo Duncan McLarenResearchers recovering a core from Little Woss Lake. Photo Duncan McLaren
This is a scanning electron microscope photo of some of the sediment from deep in the core from Topknot Lake (ca. 16,500 years ago), showing the remains of several species of diatoms, the identification of which indicates whether the water in the lake was fresh or marine at that time. In Topknot Lake there is no sign of marine diatoms, implying that relative sea level never rose to the height of the lake (13 metres above modern sea level). Photo: T. Holmes, NRCANThis is a scanning electron microscope photo of some of the sediment from deep in the core from Topknot Lake (ca. 16,500 years ago), showing the remains of several species of diatoms, the identification of which indicates whether the water in the lake was fresh or marine at that time. In Topknot Lake there is no sign of marine diatoms, implying that relative sea level never rose to the height of the lake (13 metres above modern sea level). Photo: T. Holmes, NRCAN
Core section collected from Topknot Lake. This section is from the middle of the core, with the brown sediment resulting from lots of nearby vegetation during a forested time at the lake. Photo: Duncan McLarenCore section collected from Topknot Lake. This section is from the middle of the core, with the brown sediment resulting from lots of nearby vegetation during a forested time at the lake. Photo: Duncan McLaren
Topknot Lake, close to where the team took the core. Photo: Chris HebdaTopknot Lake, close to where the team took the core. Photo: Chris Hebda

Parts of Northern Vancouver Island were ice free during the last ice age, according to new findings, giving researchers some context about the earliest human habitation on the Island.

Chris Hebda is a researcher whose graduate work looks into the pre-history of Vancouver Island. Alongside research supervisors Duncan McLaren, Quentin Mackie and the Quatsino First Nation, Hebda was trying to find an environmental record that he said “would give us a really good indication of what the environment was like as the ice began to retreat.”

“We realized the ice was coming from the coast mountains and pushing its way across Vancouver Island before it begins to retreat. That means that places on the west side of Vancouver Island and the west coast, the ice would have gotten there last. That’s going to be a better place for us to look: there’s going to be a better record and more potential for people to have been there because there is more time involved when they could have lived there, instead of it being covered in ice.”

The researchers chose two lakes — Top Knot Lake near the west coast of the Island and Little Woss Lake further inland — in which to take core samples and test for indicators of what the environment was like deep in the past. The researchers ended up going much deeper than they thought they would.

“In Top Knot lake we pulled a lot of sediment. We went over 11 metres down into the lake sediment and then we analyzed it,” Hebda said. “When we then dated some of these remains down at the bottom, we realized that the record of Top Knot Lake was extremely old. It went back probably 18,000 years at least.

“We realized that this was a special place, it had been not covered by ice and available for people to have lived nearby for a very long time. That runs counter to a lot of the understanding that was previously established in terms of the glacial history,” he said. “Basically what this tells us is that it’s a lot more complicated.”

Before this research, the theory was that the ice went from the Coast Mountains and extended out to the edge of the continental shelf, far out into the ocean. However, these ice free areas could have provided places for people to live — and routes to help them migrate further south — much earlier than previously thought.

“That also helps tie in with a lot of newer archaeological evidence emerging further south in the USA and South America,” Hebda said. “There are very old archaeological sites going back 14, 15 or 16,000 years ago. Some claims even back to 20,000 years ago. People were like ‘how could they have even gotten there, if there was ice blocking their way as they were coming across from North East Asia, Beringia (the prehistoric land bridge between Russia and Alaska) and down into the Americas?’ It’s research like this that tells us.”

Besides filling in that missing piece of the story, the research also provides the context to help find evidence of early human habitation on the Island. Analysis of diatoms and pollen in the core samples helped Hebda determine that sea level had likely never reached Top Knot Lake. In addition sea level was likely much lower than it is now.

“There was probably a lot of land out on what is now the continental shelf that was exposed as well. Top Knot Lake today is only a few kilometres from the ocean, but in the past it probably was a lot further from the ocean — at least several more kilometres of land on which people could have been living,” Hebda said. “That makes it difficult for us to be looking, because it means we need to be looking under water.”

The team was also able to find DNA belonging to fish species on which modern humans rely: Chinook salmon.

“We were able to demonstrate at Little Woss Lake that Chinook salmon were in that lake over 14,000 years ago… It’s a vital resource for a lot of people on the coast, and has been for a very long time. Not only does (this research) give us a record of the trees that were around, but also the resources and food items that people were able to use in the past.”

Hebda did acknowledge that they have not found any direct evidence of human habitation from that time period. Those questions remain unanswered. What they found, however, was contextual information to show what kind of landscape would have been around at that time, which in turn would help narrow down some potential likely settlement locations.

“Now that we understand the environmental context we can now decide to either look under water or we have to look for features that are above (sea level), but would have been interesting places for people to go to like caves, look out spots and things like that.”

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marc.kitteringham@campbellrivermirror.com

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