Salt domes

Anhydrite, or anhydrous calcium sulfate, is a mineral with the chemical formula CaSO4. It is in the orthorhombic crystal system, with three directions of perfect cleavage parallel to the three planes of symmetry. It is not isomorphous with the orthorhombic barium (baryte) and strontium (celestine) sulfates, as might be expected from the chemical formulas. Distinctly developed crystals are somewhat rare, the mineral usually presenting the form of cleavage masses. The Mohs hardness is 3.5, and the specific gravity is 2.9. The color is white, sometimes greyish, bluish, or purple. On the best deve

thumb|400px|Diapirs in a subduction|subducting plate boundary

structural dome formed of salt or halite

lake in Iberia Parish, Louisiana, USA

geologic formation

salt dome in Iran

Spindletop is an oil field located in the southern portion of Beaumont, Texas, in the United States. The Spindletop dome was derived from the Louann Salt evaporite layer of the Jurassic geologic period. On January 10, 1901, a well at Spindletop struck oil ("came in"). The Spindletop gusher blew for 9 days at a rate estimated at of oil per day. Gulf Oil and Texaco, now part of Chevron Corporation, were formed to develop production at Spindletop. The Spindletop discovery led the United States into the oil age. Prior to Spindletop, oil was primarily used for lighting and as a lubricant. Because o

unincorporated community in Louisiana, United States