Scherzonen

Within so‐called shear zones, along which variably sized units of the earth crust are subject to a displacement, numerous chemical reactions result in the re‐structuring of the rock mineralogy. This metamorphic transformation is continuously intensified from the rim to the centre of the shear zone and is chiefly controlled by pressure, temperature, and the existence of a fluid phase. As documented with the help of a concrete example chemical mass balancing in a given shear zone requires both the chemical analysis of educt and product and the documentation of eventual changes of rock density and rock volume. The latter changes allow a final distinction between isochemical and anisochemical transformation processes.