Fault gouge

The fault gouge (after the northern Swedish lake Kakir by F. Svenonius introduced 1900) is a by tectonic movements greatly destroyed and of the ground rock with unpredictable geotechnical properties. Fault gouge is often only found as breccia or rock flour and prepares for its softness and unpredictability in mining or tunneling miners or miners often far more problems than the hardest rock formations.

Formation

Fault gouge formed inside the mountain mostly by tectonic stress of the rock at low pressures and low temperatures. It can be solidified by removing dissolved calcium carbonate or silica by water penetration over time again. In greater depths, where the rock plasticity increases due to higher temperatures, arises instead of Kakirits a solidified cataclasite. In still greater depths (about 11 to 22 km below the earth's surface ) and at temperatures above about 300 ° C gives the mylonite, which has as a distinguishing feature for fault gouge and cataclasite a foliation.

Importance for the geotechnical

Made headlines last Kakiritvorkommen 2004 to 2005 during the construction of the Gotthard Base Tunnel. After particularly hard rock formations claimed the tools of the tunnel builders over the measure, the penetration of a subsequent Kakiritzone required extensive security measures.