Chemical compositional changes in fault zones are dealt with in this paper from a dynamic point of view. In fault zones consisted of silicates, relative accumulation of Si and Fe is noticed in response to the leaching of K, Na, and to a lesser extent, Mg,Ca and Ah The order of pctrogenetic elements from stable to mobile is tentatively suggested as follows: Si, Fe, Mg, Ca, Al, K and Na. The difference in ionic radius of these chemical elements is thought; to be the major factor controlling this dynamic differentiation. For fault zones along which one side is silicates and the other is carbonates, new mincrals are recognized in tectonite. On the silicate side Ca and Mg increase but Si and Al decrease; and the reverse is true on the carbonate side. This phenomenon indicates that the migration of elements in fault; zones is accelerated by dynamic cffect.
