Tectonic Record of Deformation in Intraplate Domains: Case Study of Far-Field Deformation in the Grands Causses Area, France

Oriane Parizot,Philippe Sarda,Yves Missenard,Guillaume Delpech,Pierre Vergely,Aurélie Noret,Jocelyn Barbarand,Frederic Haurine

doi:10.1155/2020/7598137

Abstract

Although tectonic plates are usually considered as rigid blocks, intraplate deformation such as lithospheric buckling or diffuse brittle deformation has been recognized for a long time. However, the origin of these deformations remains puzzling. Indeed, whereas the chronology of deformation at plate boundaries can be constrained by numerous methods (syntectonic sedimentary record, thermochronology, etc.), dating of brittle structures (faults, veins, and joints) in the far-field domains remains challenging, preventing a global interpretation of the system as a whole. In this contribution, we have combined a tectonic study with a synkinematical geochronological study of fault-related calcites of the Grands Causses intraplate domain, north of the Pyrenean orogeny. We show that these faults record a much longer history of deformation than previously thought. The Mesozoic extension, usually attributed to an early Jurassic Tethysian rifting event, probably lasted until the Barremian-Aptian epoch, in response to the Pyrenean basin’s opening. The so-called “Pyrenean deformation” of the Grands Causses domain, usually associated with the paroxysm of deformation in the belt during the late Eocene, began much earlier, around 100 Ma, and lasted for more than 60-70 Ma. This study demonstrates the high sensitivity of an intraplate domain (Grands Causses area) to record extensional or compressional deformations occurring at the edge of neighbouring plates.

Highlights

Tectonic inversion at plate boundaries has been known and studied since the beginning of the 20th century, for example, through the studies of Lamplugh [1] and Stille [2], the term “inversion” only appeared in the early 80s [3]
The lack of sedimentary records associated with deformation in the Grands Causses area has led to a poorly constrained geodynamic calendar that appeared to be controversial in various studies [13,14,15, 46]
This study demonstrates the high sensitivity of an intraplate domain (Grands Causses area) to record deformations occurring at the edge of tectonic plates

Summary

Introduction

Tectonic inversion at plate boundaries has been known and studied since the beginning of the 20th century, for example, through the studies of Lamplugh [1] and Stille [2], the term “inversion” only appeared in the early 80s [3]. The consequences of tectonic inversion at plate boundaries in the intraplate domain (far-field deformation) have not been studied as much This deformation, several hundred kilometres away from the orogeny, is generally expressed by (1) kilometre scale denudation generally associated with lithospheric folding, (2) reactivations of crustal scale inherited faults, and (3) small-scale fracturing including low-displacement faults and tectonic joints sets—all of them being able to trigger, for instance, significant fluid flow and potential mineralization.

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Discussion

Conclusion