Photographs of representative samples from the steep brecciation zone. a-c Hydrothermal breccia cemented by pyrite. Note the black color of pyrite and its powder-like appearance from the fault and its damage zone. In (c) elongated voids resemble imprints of dissolved platy mineral, likely calcite (damage zone in the hanging wall). d Pyrite veinlets in a highly cracked and argilized host sandstone from the damage zone in the footwall. The sample numbers correspond to those indicated in Fig. 1. Abbr.: Kln – kaolinite