Petroleum geologists are involved in explora-tion and production of oil and natural gas. Economic geologists explore for and develop geologic materials that have profitable uses. Engineering geologists investigate geologic factors that affect engineering structures such as bridges, buildings, airports and dams. Geochemists investigate the nature and distribution of chemical elements in rocks and minerals. Petrologists determine the origin and genesis of rocks by analyzing the textures and chemistry of minerals and rocks.
Mineralogists study the formation, composition and properties of minerals.
Geophysicists decipher the Earth's interior and magnetic, electric and gravitational fields. Geochronologists determine the age of certain rocks by calculating the rates of decay of certain radioactive elements and thus help reconstruct the geologic history of the Earth. Planetary geologists study the moon and other planets to understand the evolution of the solar system. Structural geologists study deformation, fracturing and folding that has occurred in the Earth's crust. Stratigraphers investigate the time and space relationships of layered rocks and their fossil and mineral content.