Modeling the growth of stylolites in sedimentary rocks

Abstract

[1] Stylolites are ubiquitous pressure solution seams found in sedimentary rocks. Their morphology is shown to follow two self-affine regimes. Analyzing the scaling properties of their height over their average direction shows that (1) at small scale, they are self-affine surfaces with a Hurst exponent around 1, and (2) at large scale, they follow another self-affine scaling with Hurst exponent around 0.5. In the present paper, we show theoretically the influence of the main principal stress and the local geometry of the stylolitic interface on the dissolution reaction rate. We compute how it is affected by the deviation between the principal stress axis and the local interface between the rock and the soft material in the stylolite. The free energy entering in the dissolution reaction kinetics is expressed from the surface energy term and via integration from the stress perturbations due to these local misalignments. The resulting model shows the interface evolution at different stress conditions. In the stylolitic case, i.e., when the main principal stress is normal to the interface, two different stabilizing terms dominate at small and large scales which are linked respectively to the surface energy and to the elastic interactions. Integrating the presence of small-scale heterogeneities related to the rock properties of the grains in the model leads to the formulation of a Langevin equation predicting the dynamic evolution of the surface. This equation leads to saturated surfaces obeying the two observed scaling laws. Analytical and numerical analysis of this surface evolution model shows that the crossover length separating both scaling regimes depends directly on the applied far-field stress magnitude. This method gives the basis for the development of a paleostress magnitude marker. We apply the computation of this marker, i.e., the morphological analysis, on a stylolite found in the Dogger limestone layer located in the neighborhood of the ANDRA Underground Research Laboratory at Bure (eastern France). The results are consistent with the two scaling regimes expected, and the practical determination of the major principal paleostress, from the estimation of a crossover length, is illustrated on this example.

Does stress transmission in forelands depend on structural style? Distinctive stress magnitudes during Sevier thin‐skinned and Laramide thick‐skinned layer‐parallel shortening in the Bighorn Basin (USA) revealed by stylolite and calcite twinning paleopiezometry

“…While the topography of the stylolite during its growth is sensitive to both strain rate and stress (Koehn, Ebner, Renard, Toussaint, & Passchier, ), the final topography of a stylolite is a saturation state that is reached over a short period of time, ca. 200 years (Schmittbuhl et al, ) at the end of dissolution due to local drop in solubility (Rolland et al, ). Hence, the final roughness, that is, the difference in height between two points along the stylolite plane, reflects the ambient stress at the time pressure‐dissolution stopped, and is dependent on neither strain rate nor lithology (Ebner, Koehn, Toussaint, Renard, & Schmittbuhl, ).…”

Fingerprinting stress: Stylolite and calcite twinning paleopiezometry revealing the complexity of progressive stress patterns during folding—The case of the Monte Nero anticline in the Apennines, Italy

“…In addition, their impact on reservoir properties is debated [Heap et al, 2014]. Recent understanding of the growth mechanism of stylolites during burial and contraction has led to the proposition of a new paleopiezometer based on the stylolite roughness Schmittbuhl et al, 2004;Koehn et al, 2007Koehn et al, , 2012Ebner et al, 2010aEbner et al, , 2010bRolland et al, 2012Rolland et al, , 2014. So far, this method is not often mentioned in tectonic studies, because the paleopiezometer was mainly used to reconstruct the maximum depth of burial of a formation using bedding-parallel stylolites [Ebner et al, , 2010bRolland et al, 2014].…”

Fundamental controls on fluid flow in carbonates: current workflows to emerging technologies

“…Further studies attempt to strengthen the case for the use of stylolites to estimate palaeostress, as well as their absolute values of formation stresses FUNDAMENTAL CONTROLS ON FLUID FLOW IN CARBONATESand compaction (Koehn et al 2012). These studies are supported by outcrop investigations of scaling relationships (Rolland et al 2012). Strengthening the link between experimental and field studies, Gratier (2011) emphasized the significance of the geological context in studies of pressure solution that impacts rates of fault creep, sealing processes and permeability changes over production timescales.…”