Page 63 - Ardhona 25

Figure (2)

centre of domed, upturned, and
pierced strata. Upward growth that were subject to tectonic vidual salt domes in this region
of the salt continues apace with stress. Three of the many areas are believed to have reserves of
deposition of additional strata, of salt structures in the world more than 500,000,000 barrels
and the salt mass tends to main- are representative of all; these of oil. Salt domes in northern
tain its position at or near the are the Gulf of Mexico region of Germany have produced oil for
surface. If the salt supply to the North America, the North Ger- many years. Exploration for salt
growing dome is exhausted dur- man–North Sea area of Europe, dome oil in the North Sea has
ing growth, development ceases and the Iraq–Iran–Arabian Pen- extended production offshore.
at whatever stage the dome has insula of the Middle East. The cap rock of shallow salt
reached, and the dome is bur- domes in the Gulf Coast con-
ied. Economic Significance Of
Salt Domes tains large quantities of elemen-
Distribution Of Salt Struc- Salt domes make excellent tal sulfur. Salt domes are major
tures traps for hydrocarbons because sources of salt and potash in the
Salt structures develop in any surrounding sedimentary strata Gulf Coast and Germany; halite
sedimentary basin in which thick are domed upward and blocked and sylvite are extracted from
salt deposits were later covered off. Major accumulations of oil domes by underground mining
with thick sedimentary strata or and natural gas are associ- and by brine recovery.
tectonically deformed or both. ated with domes in the United Salt domes have also been
With the exception of the shield States, Mexico, the North Sea, utilized for underground storage
areas, salt structures are wide- Germany, and Romania. In the of liquefied propane gas. Stor-
spread. By their very nature, the Gulf Coastal Plain of Texas and age “bottles” are made by drill-
classic salt domes generated by Louisiana, salt domes will be a ing into the salt and then forming
gravitational instability alone are significant source of hydrocar- a cavity by subsequent solution.
limited to areas that have not bons for some years to come. Such cavities, because of their
been subject to significant tec- Huge supplies of oil have been impermeability, also have been
tonic stress. Some salt domes found in salt dome areas off the considered as sites for disposal
do, however, occur in regions coast of Louisiana. Some indi- of radioactive wastes.
13