Ice Age Journey

 

Quetico Park contains a wide variety of different habitats: large stands of mature red and white pine, even-aged jack pine and poplar stands (the result of recent fires), wet areas with an understory of moss and overstory of black spruce, and open bogs composed of leather leaf, sphagnum moss and orchids. These and a variety of other habitats in Quetico are home to many different plants and animals.

These familiar habitats and the animals that inhabit them evolved out of the last ice-age, which reached its maximum about 20,000 years ago. (When I wrote this article in 2005 I used radiocarbon dates which are used by scientists but are significantly different than chronological dates. As an example, if a bone is dated to 10,000 radiocarbon years it is almost 12,000 calendar years old. On August 9, 2012 I changed the dates to chronological dates to more accurately reflect how long ago these events happened. )  At the peak of the last glacial period, called the Wisconsin, virtually all of Canada and a large portion of the northern United States were covered with ice. All of Minnesota was covered by glacial ice except for the southeast corner of the state.

When the glacier reached its maximum about 20,000 years ago it covered all of Ontario and almost all of Minnesota.

It has been estimated that this glacier may have been up to one mile thick. A glacier of this size obviously had an enormous impact on the land, both as the glacier was getting larger and as it was shrinking. As it grew, its enormous weight gouged out weak areas in the bedrock and ground up boulders and bedrock into a mixture of sand, gravel and small rocks. This glacial till is found throughout Quetico today. Boulders frozen into the ice sometimes left deep scratches called glacial straiae that are visible on the shores of many lakes, including Ottertrack, Knife and Cirrus. When the glacial advance stopped, long ridges of glacial till, called moraines, were left behind. A large terminal moraine, known as the Seep Rock Moraine, passes through the northeast corner of the park.

The slow retreat of the glacier was equally dramatic. The enormous amounts of water melting off the glacier created numerous lakes and ponds, and water levels were generally higher than they are today. A huge island-studded lake called Lake Agassiz temporarily covered half of Quetico Park. Big, fast-moving rivers deposited sand and silt into these enlarged lakes. When the lakes shrunk to their present size, they created flat, generally boggy areas from what had been shallow bays. The best example of this in Quetico is the flat, sandy area east of Kawa Bay of Kawnipi Lake. The Wawiag River now winds through silt and sand that was deposited in a shallow bay of what is now Kawnipi Lake.

The changes in vegetation that have occurred since the glacier retreated are striking. Fortunately, a record of the past plant communities that succeeded the glacier can be found in the bottom of lakes and ponds. Wind-blown pollen settles on lakes and sinks to the bottom, where it is eventually covered with more pollen. Since pollen from different types of plants is of different sizes and shapes, the pollen can be used to give an idea of past plant communities.

Pollen cores from the bottom of a variety of lakes and ponds in Northwestern Ontario and northern Minnesota have been analyzed, although no detailed pollen studies have been done from lakes in Quetico. Lake of the Clouds, a small lake in the BWCAW just south of Ottertrack Lake, has had an analysis of the pollen from the bottom of the lake, as has Rattle Lake, which is located just 100 miles northwest of Quetico Park. The pollen from both lakes shows similar trends in change in vegetation with time.

The bottom layer of pollen represents the first plants after the glacial retreat and the top layer represents plants from more recent years. In between is the pollen that represents the history of plant succession of the long intervening period. One of the many complicating factors is that some plant species produce large amounts of pollen that can be carried hundreds of miles by the wind, while others produce very little pollen. Analysis of pollen cores gives a picture, although somewhat fuzzy, of the vegetation change in a particular area.

It is currently thought that Lake of the Clouds became free of glacial ice about 13,000 years ago, and that Rattle Lake, being father north, became ice free a few hundred years later. The pollen from the oldest zone in both lakes indicates sparse vegetation that was composed mainly of lichens, herbs and shrubs. Pollen from higher lavels showed an increase in levels of spruce and birch. About 11,000 years ago at Lake of the Clouds and 10,500 years ago at Rattle Lake, the levels of spruce declined and levels of species of pine greatly increased.

The pollen from both lakes shows a strikingly similar pattern from tundra or tundra-like conditions, changing to a spruce-birch forest, which evolves into a predominantly pine and spruce forest. It apparently took over 2000 years for Quetico to make the transition from a land just freed from glacial ice to a forest mosaic similar to what is present today. Prior to the forest mosaic was a period when the vegetation was much different from today and when, consequently, the animals were not those we expect to see in Quetico.

This post-glacial period was characterized by a warming climate, large lakes produced by the melting of glacial ice, and vegetation that was a rich patchwork of herbs, grasses, mosses, fungus, shrubs and small trees that could have supported a high density of animals. This tundra-like vegetation is thought to have been unique, and no environment exists today that matches it. The tundra-like environment that was home to a variety of ice-age mammals is sometimes referred to as the mammoth steppe – named after the woolly mammoths, the largest of the ice-age mammals.

When the southern part of Quetico was first freed of glacial ice about 13,000 years ago, the land to the south contained a staggering array of large mammals known as the ice-age megafauna. They included woolly mammoths, mastodons, sabre-tooth tigers, camels, horses and woolly rhinoceroses. Some of these animals were of spectacular size, such as 500-lb. beavers, giant sloth that were 12 feet tall standing on their hind legs, and dire wolves weighing up to 200 pounds.

By 12 000 years ago, when all of Quetico was free of glacial ice, many of the large ice-age mammals were extinct or on their way to extinction. It is not known what caused their extinction, but there is no shortage of theories. The warming of the climate and the accompanying changes in vegetation may have made survival impossible for cold-adapted species like the woolly mammoth and woolly rhinoceros.

When the ice was retreating through Quetico, there was a Palaeoindian culture in the Americas known as the Clovis culture. The Clovis culture is characterized by large, fluted spearpoints called Clovis points. In numerous locations, Clovis points have been associated with the fossil remains of woolly mammoths. The Clovis people were successful hunters of woolly mammoths and other megafauna. Clovis points have been found in central and southern Minnesota and throughout Wisconsin, except for the northern extreme. No evidence of the Clovis culture has been found in the BWCAW or Quetico, but recently a Clovis point was reported from the Duluth area.

The extinction at the end of the last ice age left ecological niches that remain empty to this day. The warming of the climate caused a slow but steady replacement of the rich tundra-like environment, which had provided a side variety of food for grazers and browsers, with a predominantly forested environment. In North America, the mammoths, horses, camels, ground sloths, and giant beavers that once were prominent mammals disappeared with the rich post-glacial environment that they thrived in. The noted zoologist Alfred Russel Wallace once stated: “We live in a zoologically impoverished world, from which all the largest, the fiercest, and strongest forms have disappeared.”

There are skeletal remains of these megafauna throughout the Americas. In areas with hot, dry climates, such as much of the American Southwest, there are numerous well preserved remains of ice-age mammals. The LeBrea Tar Pits in Los Angeles contain thousands of skeletons from this time period, especially of carnivores such as dire wolves, sabre-tooth tigers and the American lion. In Siberia and Alaska, virtually intact woolly mammoths have been recovered from permafrost. In 1901, portions of a woolly mammoth that had been frozen for 20,000 years were eaten by a dog team when a Russian scientist came across a woolly mammoth eroding out of the ice in northern Siberia.

The acid soils of the Canadian Shield are, however, very hard on bone and antlers, and only in unusual situations do they last a decade, yet alone thousands of years. Moose bones and antlers two or three years old are usually heavily chewed by rodents and covered with fungus, moss and bacteria that rapidly recycle the valuable nutrients. Only unusual conditions, where the remains settle into a peat bog or are quickly covered with silt at the bottom of a lake, allow for long term preservation of bone.

However, the remains of a few ice-age animals have been recovered near Quetico. A skull of an extinct form of bison was found while dredging for peat on the edge of a bog near Kenora, Ontario. The skull of this bison was picked up intact by the backhoe. The operator of the backhoe joked, “I told my friends that I dug up the Devil himself.” The presence of a bison north of Lake of the Woods was a shock, but it is consistent with the concept of a tundra-grassland environment after the retreat of the glacier.

The bones of woolly mammoths have been recovered in southern Minnesota, Wisconsin and Manitoba; and recently, the bones of a mastodon were recovered in southern Wisconsin. In a few cases, the remains of large mammals have been found in association with human artefacts. The most clear-cut correlations are a bison kill site near Lake Itasca that dates back to about 8,000 years ago and a woolly mammoth in southern Wisconsin that dates to 11,000 years ago. Both of these sites had animal bones and stone tools found close together and were apparently kill sites.

The most spectacular find, however, occurred just north of Atikokan, deep in

Charlie Brooks holding a 12,000 year old caribou antler from the bottom Steep Rock Lake.

 the silt at the bottom of a lake. Iron ore was discovered at Steep Rock Lake in 1938, and diamond drilling showed that a rich ore body was located at the bottom of the lake. The demand for iron ore was high because of World War II, so the decision was made to drain the lake to get at the ore. Huge dredges were brought in to pump out the silt that covered the ore. The dredges were able to pump the silt from the bottom of the main body of the lake, but along the lakeshore the silt had to be washed into the rapidly draining lake using high pressure hoses.

On April 16, 1957, Charlie Brooks and Dick Kaemingk were surveying the monitored area along the shore. They noticed a large antler in the silt and dug it out and set it aside. Since the goal of the operation was to remove the silt and get at the ore underneath, the exact depth of the antler in the silt was not recorded. However, at the time of discovery, it was estimated that the antler was located beneath 60 to 100 feet of silt and clay. The astounding depth of silt above the antler indicated that it was probably quite old. It is of interest that there was about 450 feet of silt in the deepest part of Steep Rock Lake. The antler was deeply buried, but there were still hundreds of feet of silt below it.

The enormous amount of silt in Steep Rock was undoubtedly due to the fact that the fast flowing Seine River dropped its glacial debris into the lake when it slowed down upon entering the lake. The antler was found less than a thousand feet from the falls where the river enters the lake. Since the antler is in such good shape, it probably did not come down the Seine River and over the falls into the lake.

The caribou antler recovered by Brooks and Kaemingk was not the only one that had been noticed. Brooks remembers seeing other antlers on top of the monitor barges, presumably put there by other workers and later discarded. It is not surprising that the presence of caribou antlers was not considered unusual since woodland caribou were common in the area until the 1930’s. What is extremely fortunate is that someone had the curiosity and foresight to set one aside. (see photo of Charlie Brooks holding the 12,000 year old caribou antler from Steep Rock Lake at beginning of article)

It is ironic that the caribou antler was found near Atikokan, since Atikokan means “caribou bones” in Ojibwa. There are other references to caribou in the area, with a Caribus Lake and Caribus Creek just south of Atikokan. There is also a Caribou Lake in the eastern BWCAW. When I first saw the antler in the mid-1970’s, it had been hanging for over a decade in the entrance to the building that houses the Atikokan Library and Museum, a log building near the main street of Atikokan.

Lawrence Jackson, an archaeologist associated with Trent University, recently had the antler carbon-dated, and it was found to be approximately 12,000 years old. Originally thought to be from a woodland caribou, it was analyzed by experts and is now thought to be from a male barren ground caribou. The presence of barren ground caribou on Steep Rock Lake 12,000 years ago seems surprising, but it is consistent with evidence from pollen studies that strongly indicate that this area was primarily a mixture of spruce, birch and tundra at that time.

Barren ground caribou migrate in large herds and shed their antlers in early winter after the completion of the rut in the fall. A male caribou probably shed his antlers on the ice surface of Steep Rock Lake after spending the summer somewhere north of Atikokan. The caribou then continued on its journey with the rest of the migrating herd to its winter range to the south.

The herd of barren ground caribou that shed their antlers on Steep Rock Lake as they began their migration to their wintering grounds to the south would have been a major food resource for Palaeoindians living in the area. Caribou are hunted during the fall migration for both their hides and for food. The location of these ancient migration routes is a mystery.

In the winter of 1983, a local trapper named Phil Sawdo discovered some rock paintings on a creekside cliff north of Montgomery Lake. At this site, there are two sets of paintings about fifty metres apart. One set portrays a caribou and human-like figures and other a moose or caribou. These paintings are unique in Quetico in that they are not located on a navigable body of water; you can paddle up to all the other known pictograph sites in the park. Phil Sawdo thought that the caribou were formerly ambushed in the narrows formed by the pictograph cliff and a high hill directly opposite. Two creeks come into the area north of Montgomery, and the small valleys associated with them could have funnelled migrating caribou into the narrows where the pictographs are located.

It is not known how old the Montgomery Lake rock paintings are, and there are no rock paintings that are known to date back to Palaeoindian times. However, it is certainly possible that the Montgomery lake rock paintings depict caribou at a spot where they were hunted during migrations thousands of years ago.

Because of the similarity between barren ground caribou and woodland caribou that were present in Quetico until the 1930’s and the unknown date of the rock paintings, it is just speculation that there is a connection between the barren ground caribou antler from Steep Rock Lake and the rock paintings on Montgomery Lake. There is, however, other evidence that caribou were in the area 10,000 years ago and that they were hunted by humans. A large Palaeoindian site near Thunder Bay produced fragments of bone that have been tentatively identified as caribou. Archaeologists have suggested that this site, which is also about 10,000 years old, and others from the same time period are evidence of caribou hunting by bands of Palaeoindians along the north shore of Lake Superior.

There are also numerous Palaeoindian sites in Quetico and BWCAW that apparently date back at least 10 000 years. The culture in the area at that time is known as the Plano and is thought to have succeeded the Clovis that ended about 11 000 years ago. Because of the lack of organic material, none of these sites have been carbon dated. They have been primarily dated by the presence of large spearpoints which are very similar to those found at dated Palaeoindian sites to the south. The large spearpoints that are characteristic of Palaeoindian sites are beautifully worked and made from a variety of stones.

By the time the Clovis culture had evolved into the Plano culture, many of the ice-age megafauna were extinct. All of the evidence for Palaeoindians in Northwestern Ontario and the BWCAW is believed to be from the Plano culture. The Clovis people, and the woolly mammoths and other megafauna they co-existed with, may never have reached Quetico. However, the area was free of glacial ice in time for people of the Clovis culture and the ice-age animals they hunted to have entered and lived in Quetico. They would have, however, had to live close to the leading edge of the glacier.

So . . . I’m still looking for a Clovis point, a faced pictograph that depicts a woolly mammoth, and the bones of a mastodon or dire wolf eroding out of the silt banks of the Wawiag River. I may never find any of them, but the thought that it is possible adds another dimension to a trip into Quetico.  (An updated and enlarged treatment of Quetico’s Ice Age legacy can be found in my book.)

1 Response to “Ice Age Journey”


  • 35to 40 years ago a caribou rack was found south of georgian Bay at a site called Duncan Lake in the mud the ontario musem dated about 5000 years would this be normal ad would first nations be hunting them that far south please reply

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