ABSTRACT

Salinities of interstitial waters squeezed from three Gulf of Mexico sediment cores have been determined by the Knudsen titration method and an inductive salinometer. Water content, percent of calcium carbonate, and grain size distribution are reported for samples from the cores.

Differences in salinity as large as 2 have been found between the two methods for interstitial waters from blue clays, whereas no differences were observed for the waters from the coarser calcareous lutite. The decrease in salinity with depth shown by the inductive method for the blue clay sediment is thought to be due to the exchange and adsorption of ions by clay minerals, preferential precipitation of ionic compounds, or same type of diagenesis. The decrease in salinity is associated with a decrease in water content and all of these samples contain the greatest percentage (> 70%) of clay-sized particles. Ultrafiltration processes probably have not been active in any of the cores investigated.

It is suggested that future studies of salinities of interstitial waters in sediments should be made with both the titration and inductive methods.