Diagram of Salt Dome showing how oil and gas can be trapped along the edges and between bedding planes of rock.
Digital drawing by Amy Moe-Hoffman (Dunn-Seiler Museum)
Salt core from Tatum Salt Dome, Lamar County, Mississippi
Dunn-Seiler Museum
GEOLOGIC RESOURCES and FOSSIL FUELS
Though geologic resources make up only a small portion of the Mississippi economy, we can find measurable fossil fuels, aggregate gravel, and clay deposits here in the state.
Fossils fuels are often trapped and stored by large deposits of salt (see image on left) called salt domes or salt diapirs. Mississippi has significant salt deposits of Jurassic age in the southern half of the state. Mississippi was covered by sea for much of the Mesozoic, which allowed these massive salt deposits to form.
PETROLEUM and NATURAL GAS
Petroleum is formed from the build up and decomposition of countless marine micro-organisms. It is a fossil fuel that is the basis for many of the products we use today, including gasoline and plastics. Natural gases form when animals decompose under pressure after they are buried. They can be extracted from the Earth and either burned or combined with crude oil to produce energy.
Lignite Coal, Choctaw County, Mississippi
Dunn-Seiler Museum
COAL
Coal is formed when masses of dead plant matter build up in oxygen-poor waters, such as swamps. It can be used for energy, but the lignite coal we find here is the least compacted of all coals, making it the least efficient for energy production. Mississippi's coal deposits formed during the Carboniferous (Mississippian Period).
AGGREGATE GRAVEL and CLAY
Gravel deposits in and around the Delta Region of Mississippi have been weathered and transported from areas far to the north. These gravels are used extensively in construction and landscaping in the region.
Montmorillonite and bentonite clay are effective aquitards (layers that prevent the flow of liquids) and are used to line landfills and ponds.
