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Erratics: Exotic evidence of the last ice age. Culturally significant glacial droppings

This week Back Roads Bill is looking for your erratic locations

Humans sometimes exhibit erratic behaviour but even rocks can do so. There is also the numinous nature of stones, pebbles, boulders, scree and talus.

Most parts of Northern Ontario have been glaciated that is, ice sheets once enveloped the landscape. There are pieces of landform evidence of this momentous event.

Perhaps the most prevalent souvenir of the past is erratic boulders, large and small, mostly round-like. Why can’t erratics have an extraterrestrial source? After all, think of the house-sized boulders on the moon examined by crews of the Apollo missions.

But our erratics show no signs of the necessary flight through the Earth’s atmosphere and they can be traced to rock types characteristic of the most recent ice sheet.

Dr. Larry Dyke is a Professor Emeritus, Queen’s University and a long-time employee of the Geological Survey of Canada. “The term "erratic" is commonly used to refer to rocks that have been transported by glacier-ice to locations with a differing lithographic character,” said Dr. Dyke. “They are one of a series of indicators which mark the direction of past glacier movement. An examination of their mineralogical character leads to the identification of their parent bedrock sources, allowing for confirmation of the ice flow route.

“Boulders of a particular rock type which may be many tonnes in weight may be found sitting on a different type of bedrock; sometimes they are perched prominently in open areas. For the most part, they tend to be rounded. The surface is often fine-grained indicating grooves and scratches, remnants of the movement of the ice sheets and the constant scoring by neighbouring boulders. After the ice melted the boulders remained distributed in a random way.

Lesley Hymers is a surficial geologist with Mining Matters. The non-profit organization is dedicated to educating young people to develop knowledge and awareness of Earth sciences, the minerals industry, and their roles in society.

“Glaciers are persistent bodies of ice that move under their own weight. Glaciers played an important role in creating landscapes in most places in Canada over the past two million years," she says. "During the most recent glaciation, the Late Wisconsin, the Laurentide Ice Sheet covered most of Canada with ice that was 3 km thick.

“The ice served as an agent of change on the landscape eroding bedrock and entraining, transporting and depositing surface sediments and soils.

"When glaciers began to retreat they deposited the materials that they carried along with them, sometimes directly and sometimes in the waters that flowed off of them as they melted. In Northern Ontario, the rock outcrops, numerous lakes, and thin soils provide evidence of glaciation.

"Other landforms provide direct evidence of glacial erosion and deposition, including striations, scratches in bedrock, created by rocks and other materials that were transported in the ice and eskers, ridges of sand and gravel that were deposited by water flowing within and under glaciers.

"Kettle lakes were formed by the melting of glacial ice blocks that were trapped in sediment deposited as water flowed from the glacier. Erratics are rocks that were deposited by glaciers that differ in type from those found in the landscape where they are rest. They’re exotic.

"Erratics are plucked from bedrock surfaces, entrained by glacial ice and transported away from their place of formation. Like striations and eskers, they provide clues about the direction that the glacial ice flowed.” Glacial striae indicate the general direction of ice movement which was northeast towards the southwest.

“Erratics are important to Indigenous spirituality,” said Dr. Jonathan Pitt. His family is comprised of Ojibway and Algonquin First Nations, his heritage also includes Huron and Cree ancestry. He is currently a part-time instructor in Nipissing University's Schulich School of Education Aboriginal Education Programs and a full-time school teacher with the Near North District School Board.

Pitt said, “I have heard non-Indigenous people speak of these two sites (turtle face and bear erratics on map) both the rock resembling the turtle (Mishiikenh) and bear (Mukwa/Makwa), remembering that this area has been gone over with a fine-tooth comb due to mining in the vicinity.

"There are other rocks as well that even recently, some interested people have reached out to me for an interpretation in between Wahnapitae FN and Teme-Augama Anishnabi (Temagami FN).

"Western science might say they are erratics while Indigenous Peoples see them as cultural markers, for example, to mark a burial/mourning or waypoint/directional, for teaching and for ceremonial for vision questing. Some sites are known and some are not shared with the public for protection.

"For Indigenous Peoples, the Earth is living and all things interlock (life energy); it is these special places where our Mother can help us to relate to the universe.

"As Indigenous Peoples do not view themselves as superior to the rocks, the trees and animals. Local First Nations are aware of these sites as they hold significance or power and connect us,(often through ceremony, with the land.

“The knowledge of them is passed down within communities and families. Keep in mind what Turtle Island (North America) looked like prior to the advent of Europeans and the diverse First Nations and widespread cultures and peoples with an intense ceremonial life within a very rich spiritual landscape who inhabited this land for tens of thousands of years."

He said these sites may have been reserved for animals, plants, birds. Indigenous peoples would have perhaps only accessed or used these locations at specific times, such as when harvesting, which was linked to survival.

“These practices are still used in contemporary times, limited to a few times throughout the year. Many sites, regardless of purpose are secret or at the very least concealed to protect them. Some may no longer be used as they once were due to the introduction of settlers and industrialization.

“Within Indigenous culture, our Grandfather rocks are sentient or living spirits, we consider them to hold wisdom and memories with everything they have observed and experienced and these spirits can guide us and help us.

"What we must remember there are what Indigenous scholars refer to as linkages between and within sites. The linkages between these sites, energy and direction/navigation lines and relationship with the universe can be seen between sacred sites near Obabika, Sasaginaga, Mani-doo Aja-bikong (Devil’s Rock) and Mount Cheminis when viewed as all being interlocked."

For erratic locations across the north see the map; there is a new find, a boulder field, near Twin Lakes west of Temiskaming Shores, worth the visit. Erratics record the story of a glacier's travels. When it is time to travel, take to the back roads and look for these “exotic” souvenirs of the past.

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Bill Steer

About the Author: Bill Steer

Back Roads Bill Steer is an avid outdoorsman and is founder of the Canadian Ecology Centre
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