Salt dome

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.

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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.

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One example of an island formed by a salt dome is Avery Island in Louisiana.

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Evaporite: Evaporites are water-soluble, mineral sediments that result from the evaporation of saline water. Most evaporites are derived from bodies of sea-water, though saline lakes may also be an important source (e.g. the Great Salt Lake, Utah)....

Halite: Halite is the mineral of sodium chloride, NaCl, commonly known as rock salt. Halite forms isometric crystals. The mineral is colorless to white, light blue, dark blue, and pink. It commonly occurs with other evaporite deposit minerals such as several of the sulfates, halides and borates....

Strata: :For discussion regarding the term strata as used in geology, see stratum. See also Strata title....

Salt dome related Images and Photos (experimental)

Salt	Salt	Dome	Salt Slabs (Halite)
Le Dome	Salt House II	Salt Water Bath	Bacon Salt
Salt Marsh Dinghy	Salt & Pepper Robots	Florence Dome	Florence Dome