Geology is a broad field that encompasses the study of the Earth's composition, structure, processes, and history. This includes:

* Petrology: The study of rocks, their formation, composition, and properties.

* Mineralogy: The study of minerals, the building blocks of rocks.

* Structural geology: The study of the deformation and fracturing of rocks.

* Geochemistry: The study of the chemical composition of rocks and minerals.

* Paleontology: The study of fossils found within rocks.