Published online by Cambridge University Press: 09 July 2018
The alteration products of five sub-marine tuffs from the Mount Carmel were analysed chemically, by X-ray, D.T.A. and I.T.A. techniques and their mineralogical composition determined. Smectites are dominant in all the samples. In the less altered tuffs the smectite seems to consist of a mixture of saponite with a smectite from the beidellite-nontronite series. In the more intensely altered tuffs the saponite disappears and a swelling chlorite appears. The formation of the swelling chlorite is attributed to the degradation of the saponite. These mineralogical changes are accompanied by the loss of a large part of the alkali and alkaline earth cations.