In fault zones of the East Indian Ridge and adjacent areas of ocean floor almost monomineral sepiolite- and palygorskite clays have been found. They have been studied by a complex of optical and physical methods. Formation of authigenic sepiolites and palygorskite had occurred under influence of Mg- and Si-rich hydrothermal solutions by metasomatic replacement of montmorillonite clays, or by precipitation from saturated solutions in cracks of various rocks.

Supplement to: Skornyakova, Nadezhda S; Kurnosov, Victor B; Sval'nov, Vyacheslav N; Turanskaya, Natalya V; Tseytlin, N Yu; Shevchenko, Alla Ya (1978): Sepiolites and palygorskites of the Indian Ocean. Litologiya i Poleznyye Iskopaemyye (Lithology and Mineral Resources), 13(6), 29-45