Parks Canada
Symbol of the Government of Canada

A Guide to Geology
for Visitors in Canada's National Parks



The scenery of Canada means different things to different people. To the fisherman on its coast it is the short stretch of shoreline where he sails frequently near his home harbour. To the tourist who visits the western mountains it is rocky peaks soaring above great valleys, clear, fast streams, and campsites set in groves of well-tended trees. To the railroader it is what he sees from the train in his section, perhaps flat prairies, deep-cut gorges filled with tumbling water, shorelines of lakes or the sea. To the city dweller in Halifax or Vancouver it is the local parks, what he sees on his week-end drives or the lake country where he spends his holidays. To the men who cut pulp and lumber in Quebec or in British Columbia it is woods and hills and rivers. They think of deep snow in winter, flies in summer, the smell of fresh cut spruce and fir, beautiful autumn colours on the hillsides.

But no matter where they are or what they do, the people who pause to look around them are looking at scenery which owes most of its peculiarities to the rocks which underlie it and the particular tools which nature has used to sculpture the land.

Scenery Related to Rocks

In some regions the scenery is the direct result of the kinds of rocks which underlie the country and their condition. Miles and miles of flat prairies are underlain by flat-lying, soft rocks. Then as we approach the western mountains we note that the hills seem to be made of rocks which stand on edge. In some other areas masses of hard rock stand out as hills and the softer rocks around them underlie flat country. Thus near Montreal, and on the St. Lawrence plain to the southward, hills like Mount Royal, Mount Johnson and Mount St. Hilaire rise abruptly from flat land. Sometimes, along coastlines, hard resistant rock masses form points of land and the softer rocks are worn away from the sides to form coves. Even the colours of soils and what they are made of is dependent on the rocks underneath, so that even the kind of vegetation is ultimately the result of the kind of rocks. To understand scenery we must understand rocks.

Scenery is Everywhere Changing

Everyone has seen muddy water flowing along ditches or in streams. Mud, sand grains, pebbles and boulders are common in brooks and rivers, and all seem to be moving downstream with the current. In a year even the smallest stream carries many tons of materials down to the sea or to the lake where it empties. If we think of this process going on for thousands or millions of years we begin to realize that streams must carry enormous amounts of rock waste to the oceans. Thus valleys are being cut wider and deeper by the streams which are in them.

Along seacoasts, the scenery is changing slowly as the waves wear away the land: and currents carry debris from the cliffs out into deeper water. In high mountains, glaciers grind slowly over the land, tearing and plucking at the rocky walls which contain them. In deserts, the wind stirs up sand and dust and blows it away to dump it somewhere else. Everywhere scenery is changing, perhaps imperceptibly in a man's lifetime but in a thousand years, or a hundred thousand years, or a million years the changes we see going on around us so slowly can account for all the scenery we know. So you see that an understanding of the scenery of the world we live in requires an understanding of rocks and an understanding of the processes by which the rocks are sculptured.

Sinclair Creek and its ancestors, meltwaters from glaciers once occupying its valley, have slowly cut their way downward through the limestones in the southeast corner of Kootenay National Park to form Sinclair Canyon. From the roadway, built partly over the brook, the plunging waters can be seen still actively abrading and dissolving the limestone. © Parks Canada / D. M. Baird, 1963

Other Reasons for Knowing about Rocks

Thousands of years of human history have unfolded since rocks and minerals were first put to use by man. From the time that someone discovered that certain kinds of stones made better tools and weapons than bits of bone or wood to this day we have gradually become more and more dependent on rocks and minerals. Without them our whole material world would be different. We could build no tall buildings without steel, cement and stone. Without metals our food supply would suddenly drop off for we would have to use hand methods without machinery. Artists would have neither brushes nor pigments, our writers neither paper nor pens.

Thus to maintain our civilization we must know about rocks and minerals.

Further, to know something of the history of the earth we must examine with understanding the rocks in which the only record of that history is preserved. To know something of the interior of the earth we must examine rocks. The origins of life on earth are not recorded directly for us, but, from remains of living things preserved in rocks, we get a glimpse into many stages of the development of living things since the beginning.

Before we turn to rocks and minerals and then to scenery and its origin, let us look briefly into what the earth sciences are and how earth scientists go about their investigations.

Geology and Geologists

The study of scenery, rocks and minerals, and the structure of the earth is geology. It is really a whole group of sciences which embraces a very wide variety of fields of learning and inquiry, and, like any of the major fields of learning and inquiry, it overlaps on others. The earth's magnetism is a concern of the geologist, and of the physicist, and of a group of men who now specialize in the in-between field of geophysics. The chemistry of rocks and what constituents are to be found in them is the concern of the geologist and also the chemist. In recent years we have heard more and more of geochemistry, the area of knowledge straddling the two. Mineralogists are geologists who make a special study of how minerals, the naturally occurring chemical compounds, are put together. Their field overlaps on physics and chemistry, for both of these are concerned with the constitution of matter in all its forms.

The palaeontologist specializes in the knowledge of fossils, or the remnants of ancient living things in the rocks. He can hardly be a good palaeontologist, however, without a wide knowledge of present day living things or biology. The economic geologist is the man who specializes in the finding and development of bodies of minerals in the earth from which can be extracted something useful to mankind, like copper, iron or limestone. He must know a good deal about the minerals he is looking for, their geological occurrence and something of engineering and economics. Most geologists must know something of scenic processes, and how the surface of the land is changing. This area of geology overlaps on geography, for the geographer must know something of these, too, in order to appreciate how man can influence and be influenced by his environment.

Petrology is the study of the natural history of rocks of all kinds and stratigraphy is the study of layered or sedimentary rocks. Both these subjects of study overlap on other subjects. It is interesting to note that nowadays all these subdivisions require specialists who spend their whole professional lives investigating their own fields and applying their knowledge to the better being of mankind.

How do Geologists Work?

Now how do these various people in the geological world go about gathering and systematizing knowledge of the earth? The answer is just as varied as the kinds of geological investigation. But throughout all the kinds of investigation runs what might be termed the scientific method. We hear a great deal about this and it always seems to sound as though it were some very mysterious process entirely divorced from ordinary thinking. And yet, all that scientific method really is, is a kind of systematic investigation, something that can be applied to any question. It consists, first, in the collection of evidence or data. This may come from experience, or observation. When what information is available is all collected, it is reviewed and some preliminary conclusions called hypotheses are drawn up. Some thought is now given to the hypotheses in turn, along the lines that if that is true then we should find certain other things to be true. The next step is to test the various hypotheses to find out which one best fits the observed facts and also those ideas which have been deduced. People in many branches of learning are able to use laboratory experiments to test the various hypotheses or preliminary conclusions that the first collection of evidence has led them to. The last step in the scientific method is to decide which of the hypotheses best fit the facts and to draw conclusions.

Geological processes are so slow-moving that an enormous amount of time would be needed for experimental reproduction of some of the processes at work. Others affect very large things like mountains or ocean basins which we cannot bring into a laboratory. Many different scientific methods can be employed, of course, and in geology one of the common ones is to use sequence arrangements to see how processes operate through long periods of time. For example, when we wish to study what happens in the erosion of river bends we obviously cannot stay around for a million years to see, so a different method has to be found. If we have a hundred river bends to look at, and if they are in different stages of development, it makes sense to think that if we arrange them all in a series with the most eroded one at one end and the least eroded at the other, then all stages in the development of river bends should be represented. If we want to see what will happen to any one river bend then we have only to consult our series.

Roadcuts and steep river banks often show cross-sections from the soil down to the bedrock below. In non-glaciated regions (A) thick soils, A, grade downward through subsoils, B, and mixtures of soils and partly decayed rock, C, to the solid rock, D. The boulders above the solid rock are all derived from the bedrock below.

In glaciated regions (B) like most of Canada, fresh, solid rock, D', may appear at the surface, or it may be covered with a thin soil, A', a few feet of bedded sands and gravels, B', and glacial till which is a mixture of boulders of many kinds and finer materials, C'. Boulders in this region may be quite different from the bedrock below for they may have been transported many miles by moving ice. © Parks Canada / 1963

This method is based in turn on one fundamental supposition, that the processes which acted in the past are the same as the ones which are operating now, and that if we want to see what produced what result in the past then let us look at what process is producing that result now. In short, the present is the key to the past. This notion is one which man did not happen on all at once, even though it seems reasonable to us now. At one time, many people believed that changes were produced suddenly and drastically. Thus the Grand Canyon of the Colorado River in Arizona would be opened up by a giant convulsion of the earth, and, opened all at once. We can see now, however, that there is no need to call on great catastrophes to explain large things. We can observe the muddy Colorado River carrying off millions of tons of rock waste every year and we know that the gradual wearing away of the land by the river, even as now, if extended for a long enough period of time, would be quite sufficient for the cutting of this enormous canyon. The same applies to the canyon of the Fraser River in British Columbia and the gorge below Niagara Falls.

Thus it appears that geologists are pretty much as you might expect in their gathering and systematizing of information and knowledge about the earth, except that they have no recourse to the experimental method of proof or disproof of some of their theories and hypotheses, and that, as a result, they use other methods. One further note—because of the nature of the subject and the unavailability of direct evidence, the geological sciences must have a great deal of speculation in certain fields. No one has been able to watch mountains rise 30,000 feet into the air or minute crystals of carbon form into diamonds deep in the interior of the earth. For some, this makes for discouragement but, for others, the keen scent of mystery puzzles them enough to take up the challenge and try to see what happened, and why, from indirect evidence.

Now, let us turn to rocks and minerals and see how they originate and what makes so many different kinds of them.