Cenozoic+Era

Cenozoic Era
During the Cenozoic era, the final changes occurred which gave Canada's landforms their present shape. The continuing collision of the Pacific plate and the North American plate caused the uplifting of the Coast Mountains. Other mountain systems, including the Rockies, which had began to develop in the Mesozoic era, continued to form through folding, faulting, and the actions of volcanoes. Volcanoes released huge amounts of lava which formed plateaus between the Coast Mountains and the Rocky Mountains. The seas that had occupied the area that is now the Interior Plains disappeared as the land slowly began to rise.

 Canada and much of the world experienced an Ice Age during the last two million years. The Ice Age consisted of at least four periods of large-scale glacial activity. Huge masses of ice, or glaciers, developed as a result of a slight cooling of the earth's climate. As the glaciers moved, their actions were like giant earth-moving machines, scraping and gouging the land they covered. The Appalachian Mountains along the eastern coast and the Canadian Shield were rounded by moving ice that was often more than a kilometre thick. Large amounts of clay, silt, sand, and gravel were dumped on the lowlands surrounding the Shield as the glaciers formed and then melted away. Because this happened very recently (at least in geologic terms!), glaciation had an enormous effect on Canada's geography, setting the current pattern of lakes, rivers, hills, and plains.

1. a) How many glacial periods have there been during the last two million years?  b) Describe the effects that glaciers have had on the Canadian landscape.

 The last Ice Age ended for most of Canada as recently as 6000 years ago, but glaciers are still found in some mountain and Arctic areas. Some scientists think it is possible that the Ice Age is not over; that we are in a warm period between the fourth and fifth glacial advance.

 The Cenozoic era is the age of mammals. When the dinosaurs died out, mammals, including human beings, became dominant. The impact that we have had on the earth is enormous considering the short time that we have been here. For example, we have created huge lakes by building dams, and have increased rates of erosion by cutting forests. However, these changes to the earth's landscape are minor compared to the geologic forces at work.

2. Most geologic events happen very slowly. What is one geologic event that happens fast enough for people to see?