Water-soluble chlorine in granitic rocks

Data for total and water-soluble chlorine in 96 granitic rocks from intrusions in Scotland, N Wales and SW England show that in general a third to two-thirds of the Cl is soluble. The soluble Cl content of the rocks increases with increasing total Cl content, being highest in the granites of SW England, but the ratio of soluble to total Cl decreases with increasing Cl content. A greater proportion of Cl is in a lattice-bound state in granites which have above average Cl contents. About 70% of the Cl in kaolinised granites is in a water-soluble state. This Cl is possibly absorbed in the kaolinite. Over 80% of the Cl in six xenoliths analysed was in an insoluble state and hence probably lattice-bound.