A Closer Look at 10 Different Types of Valves. A list containing globes, gates, checks, angles and strainers can only mean weâre taking a closer look at different types of valves. In our discussion of the world of maritime supplies, a detailed listing of valves is a necessary procedure. 10 types of valves.
Canadian Shield. The Canadian Shield, also called the Laurentian Plateau, or Bouclier Canadien, is a large area of exposed Precambrian igneous and high-grade metamorphic rocks that forms the ancient geological core of the North American continent, covered by a thin layer of soil.he Canadian Shield, also called the Laurentian Plateau, or Bouclier Canadien, is a large area of exposed Precambrian igneous and high-grade metamorphic rocks that forms the ancient geological core of the North American continent, covered by a thin layer of soil.
The North American craton is the bedrock forming the heart of the North American continent and the Canadian Shield is the largest exposed part of the craton's bedrock. The Canadian Shield is part of an ancient continent called Arctica, which was formed about 2.5 billion years ago during the Neoarchean era. It was split into Greenland, Laurentia, Scotland and Siberia and is now roughly situated in the Arctic around the current North Pole.