8. Physical Geography of British Columbia
Geology
The term geology comes from the Greek words “ge” (“earth”) and “logia,” meaning the study of and discourse involving the solid Earth, including the rocks of which it is composed, and the processes by which those rocks change. Geology can also refer generally to the study of the solid features of any celestial body (such as the Moon or Mars). Geology gives insight into the history of the Earth by providing the primary evidence for plate tectonics, the evolutionary history of life and past climates.
In British Columbia, geology is important for economic development associated with mineral and hydrocarbon (oil and natural gas) exploration and harvest. Geology is valuable to the public for predicting and understanding natural hazards, the remediation of environmental problems, and for providing insights into past climate change. Geology also plays a role in geotechnical engineering and is a major academic discipline.
Formation of the mountains is a dramatic evolving process associated with geology and geomorphology. Geomorphology is the study of the process that creates and transforms the surface of the Earth. Geomorphology seeks to understand landform history and dynamics, and predicts changes through a combination of field observation, physical experiment and numerical modelling (geomorphometry).
The Earth is stratified, meaning that it has several layers. In the very centre lies the solid core, which is surrounded by a liquid core. Next is the mantle, asthenosphere, the lithosphere and finally the crust at the top.
Each of these layers is made up of different mineral composition.
Several types of rocks are found throughout the crust. Plate tectonics theory suggests that the Earth’s lithosphere is made up of seven large plates and several small ones. Rising convection plumes from the asthenosphere can force the plates to move. The plate edges are where most volcanic and earthquake activity take place. These activities move minerals and materials. Below is a map of the geologic era rock found in British Columbia.
Plate tectonics is a significant field of study in BC since as there are so many fault lines (see Figure 8.8). Faults are where plates meet. When two plates jam together, the edges often fracture and collapse forming mountain ranges in a process called orogeny.
Another significant process to the formation of the rugged terrain found in BC is isostasy, which is the process of the surface of the Earth loading and unloading. For example, the Rocky Mountains are made up of sedimentary rock which erodes relatively quickly. A process is known as isostatic rebound, occurs which is the gradual rising of land elevations as it springs back after thousands of years of being crushed under the weight of continental glaciers.
A complex system of fault lines can be found in British Columbia. In Figure 8.8, all known and inferred fault lines are present with the major fault lines in bold. The five fault li