TY - JOUR

T1 - Insights Into the Crustal-Scale Dynamics of a Doubly Vergent Orogen From a Quantitative Analysis of Its Forelands: A Case Study of the Eastern Pyrenees

AU - Grool, A.

AU - Ford, Mary

AU - Vergés, J.

AU - Huismans, R. S.

AU - Christophoul, F.

AU - Dielforder, Armin

N1 - Funding information: This study was funded by the ANR (France) PYRAMID research project. The French-Norwegian Foundation (13-06 PYR-FFTP; sedimentary basin and North Pyrenean foreland fold and thrust belt formation) supported study visits to the University of Bergen, Norway. Collaboration with CSIC Barcelona, Spain was funded by the project ALPIMED (PIE-CSIC-201530E082). A stra tigraphic correlation of the BRGM 1:50,000 geological maps supporting Figure is available as Table A1 in the supporting information. Detailed subsi dence data supporting Figure are available as Tables A2, A3, and A4 in the supporting information. Field data used to constrain the structure in the northern Pyrenees (Figures 2, 4, 5, and ) are available as Table A5 in the supporting information. We thank colleagues at the CRPG and the PYRAMID team, in particular Michel de Saint Blanquat, for fruitful discussions on the structure and nature of the Metamorphic Internal Zone in the Saint-Barthélémy area. We thank Chiara Macchiavelli for providing Pyrenean convergence rates from an early version of her work. We thank Andrew Leier, an anonymous reviewer, and the Editor for their insightful comments that helped to significantly improve the manuscript. This is CRPG contribution no. 2554.

PY - 2018

Y1 - 2018

N2 - In natural doubly vergent orogens, the relationship between the pro- and retro-wedges is, as yet, poorly constrained. We present a detailed tectonostratigraphic study of the retro-wedge of the Eastern Pyrenees (Europe) and link its evolution to that of the pro-wedge (Iberia) in order to derive insight into the crustal-scale dynamics of doubly vergent orogens. Based on cross-section restoration and subsidence analyses, we divide the East Pyrenean evolution into four phases. The first phase (Late Cretaceous) is characterized by closure of an exhumed mantle domain between the Iberian and European plates and inversion of a salt-rich, thermally unequilibrated rift system. Overall shortening (~1 mm/yr) was distributed roughly equally between both margins over some 20 Myr. A quiescent phase (Paleocene) was apparently restricted to the retro-wedge with slow, continuous deformation in the pro-wedge (~0.4 mm/yr). This phase occurred between closure of the exhumed mantle domain and onset of main collision. The main collision phase (Eocene) records the highest shortening rate (~3.1 mm/yr), which was predominantly accommodated in the pro-wedge. During the final phase (Oligocene), the retro-wedge was apparently inactive, and shortening of the pro-wedge slowed (~2.2 mm/yr). Minimum total shortening of the Eastern Pyrenees is ~111 km, excluding closure of the exhumed mantle domain. The retro-wedge accommodated ~20 km of shortening. The shortening distribution between the pro- and retro-wedges evolved from roughly equal during rift inversion to pro-dominant during main collision. This change in shortening distribution may be intrinsic to all inverted rift systems.

AB - In natural doubly vergent orogens, the relationship between the pro- and retro-wedges is, as yet, poorly constrained. We present a detailed tectonostratigraphic study of the retro-wedge of the Eastern Pyrenees (Europe) and link its evolution to that of the pro-wedge (Iberia) in order to derive insight into the crustal-scale dynamics of doubly vergent orogens. Based on cross-section restoration and subsidence analyses, we divide the East Pyrenean evolution into four phases. The first phase (Late Cretaceous) is characterized by closure of an exhumed mantle domain between the Iberian and European plates and inversion of a salt-rich, thermally unequilibrated rift system. Overall shortening (~1 mm/yr) was distributed roughly equally between both margins over some 20 Myr. A quiescent phase (Paleocene) was apparently restricted to the retro-wedge with slow, continuous deformation in the pro-wedge (~0.4 mm/yr). This phase occurred between closure of the exhumed mantle domain and onset of main collision. The main collision phase (Eocene) records the highest shortening rate (~3.1 mm/yr), which was predominantly accommodated in the pro-wedge. During the final phase (Oligocene), the retro-wedge was apparently inactive, and shortening of the pro-wedge slowed (~2.2 mm/yr). Minimum total shortening of the Eastern Pyrenees is ~111 km, excluding closure of the exhumed mantle domain. The retro-wedge accommodated ~20 km of shortening. The shortening distribution between the pro- and retro-wedges evolved from roughly equal during rift inversion to pro-dominant during main collision. This change in shortening distribution may be intrinsic to all inverted rift systems.

KW - Pyrenees

KW - cross-section restoration

KW - crustal-scale dynamics

KW - doubly vergent

KW - foreland fold-and-thrust belt

KW - quantitative

UR - http://www.scopus.com/inward/record.url?scp=85041509543&partnerID=8YFLogxK

U2 - 10.1002/2017TC004731

DO - 10.1002/2017TC004731

M3 - Article

VL - 37

SP - 450

EP - 476

JO - Tectonics

JF - Tectonics

SN - 0278-7407

IS - 2

ER -