Ruschel is an old expression of the miners' language from the Upper Harz and describes a tectonic disruption zone ("Ruschelzone") in which the affected rocks are intensely sheared , pleated, ground and crushed.
As a rule, this structure is formed along geological faults ("shear ducts") instead of the otherwise usual sharp dividing surfaces . In mining, rustling zones are a hindrance, as they usually do not contain ore and have little stability. However, if mineralizing hydrothermal solutions flow through the Ruschel zones , they can, like breccias , facilitate the impregnation of the rock with ores and lead to so-called “floor” mineralization.
According to Wimmenauer (1985), rustling as a petrographic term is more narrowly defined. They only refer to unconsolidated tectonic disruptive rocks with a relatively high proportion of medium-grain (cm to mm range) rock fragments and a low proportion of rock powder matrix .