A review of deformation pattern templates in foreland basin systems and fold-and-thrust belts: implications for the state of stress in the frontal regions of thrust wedges

S. Tavani (1) , F. Storti (2) , Olivier Lacombe (3) , A. Corradetti (1) , J.A. Muñoz (4) , S. Mazzoli (1)

1 Dipartimento di Scienze della Terra
2 Natural and Experimental Tectonics Research Group, Dipartimento di Fisica e Scienze della Terra "Macedonia Melloni"
3 iSTeP - Institut des Sciences de la Terre de Paris
4 Geomodels, Departament de Geodinàmica i Geofisica

Aesthetically appealing thrust systems and related large-scale anticlines, in both active and fossil foreland fold-and- thrust belts, and the economic potential associated with the m, have captured the interest of structural geologists for many decades. As a consequence, a large amount of data on sub -seismic deformation patterns from thrust-related an- ticlines is available in the literature. We provide a review of deformation pattern templates from fi eld data in foreland fold-and-thrust-belts and show that the most frequent tre nds of sub-seismic syn-orogenic deformation structures hosted in km-scale thrust-related folds frequently and pa radoxically indicate a syn-th rusting strike-slip stress fi eld con- fi guration, with a near-vertical σ 2 and a sub-horizontal σ 3 , rather than a contractional one where the latter is expected to be the vertical principal axis of the stress ellipsoid. This a pparent inconsistency between sub-seismic syn-orogenic deformation structures and stress fi eld orientation is here named “ the σ 2 paradox ” . Field data support a possible expla- nation of the paradox, provided by the major role played by i nherited early-orogenic extensional deformation struc- tures on thrust fault nucleation. Nucleation of major thru sts and their propagation is facilitated and driven by the positive inversion and linkage of the early-orogenic sub-s eismic extensional inheritance developed in the foreland basin. This process eventually leads to the development of l argereversefaultzonesandcanoccurbothincontractional and strike-slip stress fi eld con fi gurations

Domaines: Sciences de la Terre

S. Tavani, F. Storti, Olivier Lacombe, A. Corradetti, J.A. Muñoz, et al.. A review of deformation pattern templates in foreland basin systems and fold-and-thrust belts: implications for the state of stress in the frontal regions of thrust wedges. Earth-Science Reviews, 2015, 141, pp.82-104. ⟨10.1016/j.earscirev.2014.11.013⟩. ⟨hal-01393309⟩