The roughness of stylolites: Implications of 3D high resolution topography measurements

Abstract

Stylolites are natural pressure-dissolution surfaces in sedimentary rocks. We present 3D high resolution measurements at laboratory scales of their complex roughness. The topography is shown to be described by a self-affine scaling invariance. At large scales, the Hurst exponent is $ζ_1 \approx 0.5$ and very different from that at small scales where $ζ_2 \approx 1.2$. A cross-over length scale at around $Ł_c =1$~mm is well characterized. Measurements are consistent with a Langevin equation that describes the growth of a stylolitic interface as a competition between stabilizing long range elastic interactions at large scales or local surface tension effects at small scales and a destabilizing quenched material disorder.