TOtal dissolution involving total disappearance of the solid phase. In general it is a complex process of reciprocal reaction between magma and invaded rock. During the process of reaction, due to ionic exchange between liquid and crystals, minerals are changed into those crystalline phases with which the liquid was already saturated. The end product is a contaminated igneous rock which was at no time entirely liquid and which is made up of materials contributed partly by the original rock and partly by the wall-rock. The rock formed in this way is naturally of hybrid origins, which are particularly common along the borders between intrusive and invaded rocks.