Amorphous to weakly crystalline detrital muds, eroded from tropically weathered basalt, apparently are rapidly forming illite and montmorillonite in the marine environment near the Hawaiian Islands. Seaward changes in alumina-silica ratios, nonexchangeable cations, and mineralogy, as well as young K-Ar ages, support the interpretation that a substantial part of the marine clay near the Islands is authigenic. Other investigators have shown that part of the marine chlorite has replaced gibbsite. The evidence is not sufficient to show what amount of the kaolinite also found in the muds, if any, is authigenic.
These results support the theory that reactions between ocean water and silicates are a major factor in alkali ion fixation and pH control of the oceans.