Bulletin 93—Bromine in the Salado Formation, Carlsbad potash district, New Mexico

By S. S. Adams, 1969, 122 pp, 16 tables, 46 figs.

The bromine content of halite and sylvite in the Salado Formation was investigated in drill cores and underground workings of the International Minerals and Chemical Corporation mine in the Carlsbad potash district, southeast NM. The bromine content of halite ranges from 25–105 ppm. This low concentration, in the presence of sylvite, suggests that much of the Salado Formation is second cycle. Changes in the bromine content of halite across stratigraphic boundaries correlate with changes in mineralogy and lithology. This is interpreted as evidence that these features formed during deposition and the bromine content of the halite has not changed substantially since deposition.

The bromine contents of halite and sylvite in the first ore zone, the principal potash bed in the district, suggest that the initial precipitation of a halite-sylvite assemblage was succeeded by the precipitation of halite-carnallite. Carnallite replaced some of the sylvite but was subsequently converted to sylvite during early diagenesis.

The bromine content of halite aids in identifying salt horses in drill cores. Bromine distributions are also of value in regional exploration. Most geochemical processes indicated on the basis of bromine concentrations in halite and sylvite are supported by independent mineralogic, stratigraphic, and textural criteria.

The Permian sedimentary basin of the southwestern U.S. underlies parts of Texas, NM, Oklahoma, Kansas, and Colorado. It has an area of about 155,000 mi². The Carlsbad potash district may be considered as belonging to the west Texas-southeastern NM part of the basin, which covers about 50,000 mi². Within the more limited area of the Carlsbad potash district, seven companies presently mine potassium salts. This report is based on studies made of the drill cores and underground workings of the International Minerals and Chemical Corporation mine.