1 Geology and its branches

Definition

• Geology (the science of the Earth) studies everything related to the Earth: its components, movements, history, phenomena and wealth.

Main branches

• Physical geology: the external and internal processes that affect the rocks of the Earth's crust.
• Mineralogy and crystallography: minerals, their physical and chemical properties and their crystal systems.
• Hydrogeology: groundwater aquifers, and the supply, withdrawal and use of water in agriculture and land reclamation.
• Structural geology: the structures in rocks formed by external and internal forces acting on the crust.
• Stratigraphy: the rules and conditions of the formation of layers and their relations to each other.
• Paleontology: fossils and the remains of animals (vertebrates, invertebrates) and plants, used to find the geological age and the environment of the sediments.
• Geochemistry: the chemical composition of minerals and rocks, the distribution of elements in the crust, and the type and ratio of ores.
• Engineering geology: mechanical and geometrical properties of rocks, for building dams, tunnels, bridges, skyscrapers and towers.
• Petroleum geology: formation, migration and accumulation of oil and gas in reservoir rocks.
• Geophysics: exploring oil traps, ore deposits and groundwater with sensitive physical devices.