Geology Geology is the study of the Earth, the materials of which it is made, the structure of those materials, and the processes acting upon them. It includes the study of the organisms which inhabit our planet. A very important part of geology is the study of how Earth’s materials, structures, processes and organisms have changed over time. Geologists work to understand the history of our planet. The better they can understand Earth’s history the better they can foresee how events and processes of the past might influence the future.