Marten Hills obsidian find unique, North Dakota stones common

Pearl Lorentzen
Lakeside Leader

Last year, Brian Leslie and a fellow employee at Tree Time Services found an obsidian blade in the Marten Hills east of Slave Lake. It is the first piece of obsidian from a British Columbia volcano found in the area and one of the furthest from the source.

However, the majority of stones near Lesser Slave Lake aren’t good for flint knapping, so archaeologists often find stones from North Dakota and Manitoba in the area. This is likely due to geography and animal migration.

Obsidian is an unusual find, says Leslie, so he and his partner investigated where it came from. Around Sundre and Calgary, most obsidian comes from eastern Washington State. He and his colleague expected the Marten Hills obsidian to be from Washington, so were surprised to discover it came from Mt. Edziza in northern British Columbia.

Mt. Edziza is further north, but also further west. It is 1,700 kilometres away.

Looking at a map, Mt. Edziza is fairly close to the BC coast. It is only one mountain range east of the Pacific Ocean. It is southeast of Juneau, Alaska in the interior of BC. There are several mountain ranges and the continental divide between it and the Peace Country, west of Lesser Slave Lake.

Mt. Edziza obsidian, says Leslie, is fairly common in Peace Country and in the Yukon. It has also been found around Fort McMurray, which is further east than Lesser Slave Lake.

Leslie says obsidian is basically lava glass. As such, it is easy to flint-knap and very sharp. People who are learning to flint nap will often use obsidian or the bottom of beer bottles. Some surgeons use obsidian scalpels for very fine cuts. Unfortunately, it breaks very easily. It is created when lava from a volcano meets water.

Merriam-Webster Dictionary defines knap as “to break with a quick blow and especially : to shape (something, such as flints) by breaking off pieces.”

The obsidian has marks from the flint block which it was cut off of, Leslie continues, which he says is unusual. When knapping, an artisan would shape a large piece of stone, like obsidian, chert, or flint. From these, repeatable knives or other blades could be chipped off quickly.

Not a lot is known about the pre-European contact trading patterns of Indigenous peoples in North and South America, says Leslie. There is evidence however that they travelled extensively by boat and over land.

When you carry everything you own with you, you can cover a lot of land quickly. A person walking 10 kilometres a day, could cross the 1,700 km from Mt. Edziza to the Marten Hills in 170 days, basically six months.

Deer Mountain in the Swan Hills is “chock full of archaeological sites,” says Leslie. Many of these are quarries for Swan River chert. Chert, flint, and obsidian are types of stone which knap well. Otherwise the stones in the Lesser Slave Lake area aren’t good for making stone tools.

While obsidian is a rare find in the Lesser Slave Lake area, there are several types of stones from a far away which are common. These include Knife River flint (KRF) from North Dakota and Grizzly Ridge chert from Manitoba.
As all tools were made out of stones, people went through a lot of stone, and stones were likely traded, he says. There’s a quality difference between tools made with different stones. The difference between an obsidian blade and one made of random river stone is like the difference between a Japanese steel artisan knife and a cheap knife in the store.

Like obsidian Knife River flint (KRF) is an “aesthetically pleasing stone,” says Leslie. It is dark brown, but when it is heated it becomes see-through. Some other stones turn pink when heated. Heating also makes some stones stronger.

Some people may have migrated seasonally to the Lesser Slave Lake area following the bison, says Leslie. Then winter in the south.

Lesser Slave Lake is on the southern edge of the boreal forest. To the south and east is the Canadian Prairies. To the west is the Peace Country, which is another prairie which ends at the Rocky Mountains.

While there are various hills, coulees, and river valleys within the prairies, it is relatively easy to travel overland and by water. Like the birds which migrate over the region, pre-European contact large herds of bison roamed the plains and boreal forest from the Rockies to the Appalachian Mountains and Alaska to the Gulf of Mexico.

An article called ‘Knife River Flint quarries and the Alberta connection’ on says, “over the course of 13,000 years, KRF was shaped into projectile points, tools, and some unusual . Its translucent, coffee-brown colouration, ability to flake predictably, and stay sharp were desirable qualities. Some speculate that the bison-hunting peoples of the past may have even attributed spiritual properties to the stone. Whatever the reasons, KRF was considered significantly more valuable than other local materials, so great effort was invested in its procurement.”

Obsidian from a northern British Columbia volcano found near the headwaters of the Fawcett River in the Marten Hills east of Slave Lake. The volcano is 1,700 kilometres away across the continental divide and several mountain ranges. Photo courtesy of Tree Time Services.
A Knife River Flint found near Lac La Biche in 2013. It is just over one centimetre wide. This caramel-coloured rock likely came from North Dakota, which is at least 1,300 kilometres away. Although not found naturally in the boreal forest, it is a relatively common archaeological find in the boreal forest. Photo courtesy of Tree Time Services.

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