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.

Related Topics:
Evaporite - Halite - Strata - 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.

Related Topics:
Sea - Ocean - Evaporate - Sediment - Density - Kilometer

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

Related Topics:
Avery Island - Louisiana

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