Der Magmenaufstieg in rotierenden Systemen

The present discussion about magmatic processes develops out of granite tectonics which goes back toHans Cloos (1922). Kinematics and dynamics of the flow within an uprising magma result from archimedean buoyancy. This force equilibrates all disequilibria of the terrestrial density distribution caused by thermal actions. Magmatic uprising, however, is not a strictly archimedean process, but suffers from distortion, deformation, deviation, and self-rotations caused by secondary forces which originate from the rotation of the earth. Simultaneous step wise crystallization of the magma leads to gravitational differentiation which is accompanied by lateral differentiation. Thus, in the end the magma solidifies asymmetrically, fractionated, and exhibiting an azimuthal tendency. These features may be expressed either by an individual magmatic body, or by a whole petrographic province. Apparently, no magma is able to rise homogeneously and vertically upwards. The entire process of magmatic uprising as well as the resulting inner fabric and outer shape appear to be controlled by the laws of Archimedes, Coriolis, and Cloos.