Geological shields are large areas of exposed bedrock that form the ancient core of continents. They consist mainly of igneous and metamorphic rocks and are typically found in stable regions of the Earth's crust. These shields are often characterized by their flat terrain and can be rich in mineral resources. One of the most well-known geological shields is the Canadian Shield, which covers parts of Canada and the northern United States. Geological shields play a crucial role in understanding the Earth's history, as they contain some of the oldest rocks on the planet, providing insights into the processes that shaped the Earth's crust.