Biologically-initiated rock crust developed on two types of surface (tectonic vs. non-tectonic) in Střeleč Quarry (Czech Rep.) was studied. Using the drilling resistance method, relative erodibility indicator (REI) and measuring of tensile strength in situ, it was determined that there is no relevant difference in the protection by biologically-initiated rock crust between tectonic and non-tectonic surfaces.
Biocolonized tectonic surfaces seem to have generally the same mechanical properties as non-tectonic biocolonized surfaces.