Definition - What does Salt Dome mean?
A Salt Dome is a structural dome that is formed when salt intrudes vertically into a surrounding rock strata and forms a diapir. The diapir appears as a geologic intrusion over the brittle overlying rocks. Salt domes are an important topic of study when petroleum geology strata needs to be studied as they are impermeable and can cause stratigraphic traps.
Petropedia explains Salt Dome
Salt domes generally form mushroom-shaped diapirs which intrude into oil reservoirs and form stratigraphic traps. These salt domes mushroom with time and continue growing until they appear on the earth's surface. On the surface they can be seen easily as rocks become white in color and get covered by salt. These domes are usually formed due to the relative buoyancy of salt when it is below the other minerals or a mineral basin. As a result, the salt flows upwards and slowly forms salt domes and other dome like structures that gradually keep increasing in the size. Hydrocarbons are usually found near salt domes.