The role of inheritance in forming rifts and rifted margins and building collisional orogens: a Biscay-Pyrenean perspective

Abstract

The aim of this paper is to provide a conceptual framework that integrates the role of inheritance in the study of rifts, rifted margins and collisional orogens based on the work done in the OROGEN project, which focuses on the Biscay-Pyrenean system. The Biscay-Pyrenean rift system resulted from a complex multistage rift evolution that developed over a complex lithosphere pre-structured by the Variscan orogenic cycle. There is a general agreement that the Pyrenean-Cantabrian orogen resulted from the reactivation of an increasingly mature rift system along-strike, ranging from a mature rifted margin in the west to an immature and segmented hyperextended rift in the east. However, different models have been proposed to explain the preceding syn-rift evolution and its influence on the subsequent reactivation. 
 
 Results from the OROGEN project show a sequential reactivation of rift inherited decoupling horizons and identify the specific role of exhumed mantle, hyperextended and necking domains during reactivation. They also highlight the contrasting fate of segment centres vs. segment boundaries during convergence, explaining the non-cylindricity of internal parts of collisional orogens. Results from the OROGEN project also suggest that the role of inheritance is more important during the initial stages of subduction and collision, which may explain the complexity of internal parts of orogenic systems. In contrast, once tectonic systems get more mature, orogenic evolution becomes mostly controlled by first-order physical processes as described in the Coulomb Wedge theory for instance. This may account for the simpler and more continuous architecture of external parts of collisional orogens. It may also explain why most numerical models can reproduce mature orogenic and rift architectures with better accuracy compared to the initial stages of such systems. Thus, while inheritance may not explain steady-state processes, it is a prerequisite for comprehending the initial stages of tectonic systems. The new concepts developed from the OROGEN research are now ready to be tested at other orogenic systems that result from the reactivation of rifted margins, such as the Alps, the Colombian cordilleras and the Caribbean, Taiwan, Oman, Zagros or Timor. 

The syn‐rift tectono‐stratigraphic record of rifted margins (Part II): A new model to break through the proximal/distal interpretation frontier

“…Although model‐driven approaches have historically caused significant misinterpretations and remain problematic when blindly applied (e.g. review by Manatschal, Chenin, Lescoutre, et al., 2021), having a first‐order template may help when attempting to unravel the tectono‐stratigraphic record of uncalibrated distal domains. Indeed, sedimentary facies of given age may vary between the shallow‐water proximal domain and deep‐water hyperextended domain, and thus one cannot rely on the seismic signature/sedimentary field observations to correlate sedimentary units.…”

Geodynamic evolution of a wide plate boundary in the Western Mediterranean, near-fieldversusfar-field interactions

“…These different boundary and body forces apply on a lithosphere with a given rheology and a given pre-orogenic tectonic history and inheritance is thus important to consider, especially in the early history of mountain belts (Manatschal et al, 2021). The nature of the deep crust during the formation of the orogen is thus an important question to address.…”

“…The early Cretaceous rifting episode was locally associated with mantle exhumation and serpentinisation, but the intensity of this serpentinisation differs between peridotite bodies that were exhumed within the upper crust during rifting. Such weak levels might have nevertheless been used as decoupling levels during convergence (Tugend et al, 2014;Manatschal et al, 2021). Models of formation of magma-poor passive margins suggest that weakening of the crust and weakening of the upper mantle by serpentinisation during extension can lead to lower crust and mantle exhumation with low-angle extensional shear zones (Lavier et al, 1999(Lavier et al, , 2019.…”

“…6). If the geometry of the belt and the rheological properties of the lithosphere (elastic thickness) are strongly impacted by the heritage from the pre-orogenic rifting episode (Angrand et al, 2018;Espurt et al, 2019;Manatschal et al, 2021), the overall tectonic evolution is also dependent on far-field stresses and on the progressive localization of a new zone of deformation during the Late Cretaceous (Dielforder et al, 2019).…”

Passive imaging of collisional orogens: a review of a decade of geophysical studies in the Pyrénées

“…Its global architecture is also notably simpler than the nearby Alps because oceanic subduction, with all the potential implications, never occurred along this convergent margin. Indeed, it is now well accepted that its Late Cretaceous and Tertiary orogenic evolution results from the shortening of narrow Cretaceous hyper-extended rifts and not from an oceanic basin sensu stricto (see paper for a synthesis on the rift-to-orogenic evolution recorded in the Pyrénées and also the review papers of Manatschal et al, 2021and Mouthereau et al, 2021 in this special issue). The moderate convergence (<200 km) (e.g., Muñoz, 1992;Teixell et al, 2018;Mouthereau et al, 2014) also implies that the records of the pre-collisional history remain largely preserved, which also makes the Pyrénées a unique place to study the control of rift inheritance on the formation of collisional orogens (see Manatschal et al, 2021, this special issue).…”