Does roughening of rock-fluid-rock interfaces emerge from a stress-induced instability?

Eric Bonnetier (1) , Chaouqi Misbah (2) , François Renard (3, 4) , Renaud Toussaint (5) , Jean Pierre Gratier (6)

1 EDP - Equations aux Dérivées Partielles
2 LSP - Laboratoire de Spectrométrie Physique
3 LGCA - Laboratoire de Géodynamique des Chaines Alpines
4 PGP - Physics of Geological Processes [Oslo]
5 IPGS-GE - Géophysique expérimentale (IPGS)
6 LGIT - Laboratoire de Géophysique Interne et Tectonophysique

Non-planar solid-fluid-solid interfaces under stress are very common in many industrial and natural materials. For example, in the Earth's crust, many rough and wavy interfaces can be observed in rocks in a wide range of spatial scales, from undulate grain boundaries at the micrometer scale, to stylolite dissolution planes at the meter scale. It is proposed here that these initially flat solid-fluid-solid interfaces become rough by a morphological instability triggered by elastic stress. A model for the formation of these unstable patterns at all scales is thus presented. It is shown that such instability is inherently present due to the uniaxial stress that promotes them, owing to the gain in the total elastic energy: the intrinsic elastic energy plus the work of the external forces. This is shown explicitly by solving the elastic problem in a linear stability analysis, and proved more generally without having resort to the computation of the elastic field.

Domains: Earth Sciences

Eric Bonnetier, Chaouqi Misbah, François Renard, Renaud Toussaint, Jean Pierre Gratier. Does roughening of rock-fluid-rock interfaces emerge from a stress-induced instability?. The European Physical Journal B: Condensed Matter and Complex Systems, 2009, 67 (1), pp.121-131. ⟨10.1140/epjb/e2009-00002-2⟩. ⟨insu-00352886⟩