Ontario Grade 9 Geography Practice Exam

The type of rock predominantly found in the Interior Plains is sedimentary rock, which is significant primarily because it contains valuable resources such as oil and natural gas. The formation of sedimentary rock occurs through the accumulation and compaction of sediments, which often include organic materials. In regions like the Interior Plains, ancient sea beds and river systems deposited organic matter over millions of years, leading to the creation of fossil fuels.

These resources are economically important, as they are used to generate energy, fuel transportation, and serve as raw materials for various industries. Sedimentary rocks also often have porosity and permeability, which are essential qualities for storing these hydrocarbons.

In contrast, igneous rocks, while useful for construction due to their strength, do not typically have the same resource-rich qualities as sedimentary formations. Metamorphic rocks and granite also do not hold the same significance in the context of oil and natural gas reservoirs. Understanding the rock types in different geographic regions highlights their economic implications and the geological history that shaped them.