A number of experienced geologists go into business for themselves, offering their services as consulting geologists to the public. Economic geologists locate earth materials such as minerals and solid fuels. Petroleum geologist attempt to locate oil and natural gas deposits below the earth's surface. Engineering geologists evaluate sites for construction of buildings, highways airports, tunnels, dams and other structures. The latter also study the flow of groundwater and pollution effects.
Most geologists divide their time among field and laboratory work, data analysis, and office duties.
For example, some geologists spend much of their time in the field. Once the field work is completed, the samples and other data that have been collected are usually taken to the laboratory for more detailed study. The rock samples may be x-rayed, studied under a polarizing or electron microscope, and subjected to chemical analysis. The geologists may also conduct laboratory experiments designed to test theories that have been proposed to explain geologic phenomena. Often, good geologic work is good detective work.