Thick-Skinned and Thin-Skinned Tectonics: A Global Perspective

Abstract

This paper gives an overview of the large-scale tectonic styles encountered in orogens worldwide. Thin-skinned and thick-skinned tectonics represent two end member styles recognized in mountain ranges. Both styles are encountered in former passive margins of continental plates. Thick-skinned style including the entire crust and possibly the lithospheric mantle are associated with intracontinental contraction. Delamination of subducting continental crust and horizontal protrusion of upper plate crust into the opening gap occurs in the terminal stage of continent-continent collision. Continental crust thinned prior to contraction is likely to develop relatively thin thrust sheets of crystalline basement. A true thin-skinned type requires a detachment layer of sufficient thickness. Thickness of the décollement layer as well as the mechanical contrast between décollement layer and detached cover control the style of folding and thrusting within the detached cover units. In subduction-related orogens, thin-and thick-skinned deformation may occur several hundreds of kilometers from the plate contact zone. Basin inversion resulting from horizontal contraction may lead to the formation of basement uplifts by the combined reactivation of pre-existing normal faults and initiation of new reverse faults. In most orogens thick-skinned and thin-skinned structures both occur and evolve with a pattern where nappe stacking propagates outward and downward.

Shear Velocity and Radial Anisotropy beneath Southwestern Canada: Evidence for Crustal Extension and Thick‐Skinned Tectonics

“…Up to now, the deformation of the Foreland Belt has been explained by the "thin-skinned" tectonic model (e.g., Campbell, 1973;Pfiffner, 2006Pfiffner, , 2017Price, 1981), which assumes that the sedimentary cover is detached from its crystalline basement along a mechanically weak décollement horizon (Pfiffner, 2006). The anisotropic pattern from our study (see Figures 7a and 11) displays similar dipping structures in geometry to the present-day east-verging imbricate thrust sheets in the Foreland Belt of the southern Canadian Cordillera (Price, 1981).…”

Miocene basement exhumation in the Central Alps recorded by detrital garnet geochemistry in foreland basin deposits

“…The Central European Alps and their northern foreland basin, formed through the collision of the European and the Adriatic continents since the Eocene Handy et al, 2010), are a classic example of such interactions (e.g. Schlunegger et al, 1998;Pfiffner et al, 2002;Vernon et al, 2008Vernon et al, , 2009Baran et al, 2014;Fox et al, 2015). The exhumation of large slices of mid-crustal rocks from the European plate, the so-called external crystalline massifs, occurred relatively late in the Alpine evolution, probably during the late Miocene, although the exact timing is not well constrained.…”

Miocene basement exhumation in the Central Alps recorded by detrital garnet geochemistry in foreland basin deposits

“…In 45 most geometric reconstructions (e.g. Pfiffner, 1986Pfiffner, , 2017Schmid et al, 2004), the contact between 46 the crystalline basement and the overlying Mesozoic cover is assumed to be relatively flat, and the top 47 of the crystalline basement is hypothesized to be less than one kilometer above the modern 48 topography. Conversely, a new reconstruction of this tectonic contact allows for a substantially greater 49 amount (~8 km) of (now eroded) crystalline rock on top of the present-day topography (Nibourel et 50 al., 2018).…”