Isotope geochemistry of water in Gulf Coast salt domes.

Water found as active leaks and isolated pools in the Weeks Island, Jefferson Island, and Belle Isle salt mines of S Louisiana has del ¹⁸O values ranging from -4 to +ll.5%o and delD/_% values from -2.3 to -53%o. Most samples are too enriched in ¹⁸O to be meteoric waters. It is concluded that the nonmeteoric waters are formation waters which have become incorporated in the salt. From the observed ¹⁸O enrichment it is calculated that the formation waters were incorporated during diapiric rise of the salt at a depth of 3-4 km and have been trapped within the salt for 10-13 m.y. Large volumes of salt within salt domes are not naturally penetrated by meteoric groundwaters but can contain limited amounts of trapped formation water. - from Authors