A salt dome is formed when a thick bed of evaporite minerals (mainly salt, or halite) found at depth intrudes vertically into surrounding rock strata, forming a diapir. Evaporites are water-soluble, mineral sediments that result from the evaporation of saline water. ... Halite is the mineral of sodium chloride, NaCl, commonly known as rock salt. ... Interstate road cut through limestone and shale strata in eastern Tennessee In geology and related fields, a stratum (plural: strata) is a layer of rock or soil with internally consistent characteristics that distinguishes it from contiguous layers. ... Pluton redirects here. ...

The salt that forms these deposits was laid down in prehistoric times, mainly in places where inland seas were periodically connected and disconnected from oceans. As these seas are cut off from the main body of water, the water evaporates, leaving immense salt pans. Over time, the salt is covered with sediment and becomes buried. Since the density of salt is generally less than that of surrounding material, it has a tendency to move upward toward the surface, forming large bulbous domes, sheets, pillars and other structures as it rises. In cross section, these large domes may be anywhere from 1 to 10 kilometers across and extend as far down as 6.5 kilometers. Sunset at sea Look up Sea on Wiktionary, the free dictionary Look up maritime in Wiktionary, the free dictionary A sea is a large expanse of saline water connected with an ocean, or a large, usually saline, lake that lacks a natural outlet such as the Caspian Sea and the... Ocean (from Okeanos, a Greek god of sea and water; Greek ωκεανός) covers almost three quarters (71%) of the surface of the Earth. ... Evaporation is the process whereby atoms or molecules in a liquid state (or solid state if the substance sublimes) gain sufficient energy to enter the gaseous state. ... Sediment is any particulate matter that can be transported by fluid flow and which eventually is deposited as a layer of solid particles on the bed or bottom of a body of water or other liquid. ... Density (symbol: ρ - Greek: rho) is a measure of mass per unit of volume. ... A kilometre (American spelling: kilometer) (symbol: km) is a unit of length equal to 1000 metres (from the Greek words khilia = thousand and metro = count/measure). ...

One example of an island formed by a salt dome is Avery Island in Louisiana. Avery Island is located in Iberia Parish, Louisiana, United States, about three miles inland from Vermilion Bay, which in turn opens onto the Gulf of Mexico. ... State nickname: Pelican State Other U.S. States Capital Baton Rouge Largest city New Orleans Governor Kathleen Blanco (D) Official languages None; English and French de facto Area 134,382 km² (31st)  - Land 112,927 km²  - Water 21,455 km² (16%) Population (2000)  - Population 4,468,976 (22nd)  - Density 39. ...

Commercial uses

The rock salt that is found in salt domes is mostly impermeable. As the salt moves up towards the surface, it can penetrate and/or bend strata of existing rock with it. As these strata are penetrated, they are generally bent slightly upwards at the point of contact with the dome, and can form pockets where petroleum and natural gas can collect between impermeable strata of rock and the salt. The strata immediately above the dome that are not penetrated are pushed upward, creating a dome-like reservoir above the salt where petroleum can also gather. These oil pools can eventually be extracted, and indeed form a major source of the petroleum produced along the coast of the Gulf of Mexico. Nodding donkey pumping an oil well near Sarnia, Ontario, 2001 Petroleum (from Latin petra – rock and oleum – oil), crude oil, sometimes colloquially called black gold, is a thick, dark brown or greenish liquid. ... Natural gas (commonly refered to as gas in many countries) is a gaseous fossil fuel consisting primarily of methane. ... Gulf of Mexico. ...

Other uses include storing oil, gas or even hazardous waste in large caverns, as well as excavating the domes themselves for uses in everything from table salt to the granular material used to prevent roadways from icing over. Sodium chloride, also known as common salt, table salt, or halite, is a chemical compound with formula NaCl. ...

See also

• Strategic Petroleum Reserve