Branches of geology and their interrelationships

Geology is a broad science and is divided into branches, each studying one aspect of the Earth. They are closely linked.

Main branches

• Mineralogy and crystallography: minerals and their crystal forms.
• Petrology: origin, composition and classification of rocks.
• Structural geology: folds, faults, joints and other deformation features.
• Physical geology: surface and internal processes (weathering, erosion, volcanism).
• Historical geology and stratigraphy: Earth history and the order of rock layers.
• Palaeontology: fossils and ancient life.
• Geomorphology: landforms and their development.
• Hydrogeology: groundwater.
• Economic geology: ore and fuel deposits.
• Engineering geology: application to civil works.
• Geophysics and geochemistry: physical and chemical study of the Earth.

Interrelationship

• Mineralogy gives the base for petrology, because rocks are aggregates of minerals.
• Petrology and structural geology together explain how rock bodies are formed and deformed.
• Stratigraphy uses palaeontology (fossils) to date and correlate layers.
• Physical geology and geomorphology explain how structures are shaped into landforms.
• Engineering geology uses nearly all of them to solve practical civil engineering problems.