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

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.

How sensitive are intraplate inherited structures? Insight from the Cévennes Fault System (Languedoc, SE France)

“…As a whole, this study highlights brittle deformation in the Languedoc region contemporary with the formation of the orogen in Palaeocene and Eocene times (Grool et al 2018), as also observed during the emplacement of the SE Pyrenean thrust sheet sequence (see fig. 6 of Cruset et al 2020), a result that is in agreement with those obtained in the Grands Causses area, to the north, also showing a long and continuous deformation during the Eocene (Parizot et al 2020). On the other hand, this deformation chronology highlighted in the Languedoc region does not mimic the sequence of paroxysmic events in the orogen.…”

“…5a). This reactivation of the NE-SW inherited structures is coeval with (1) denudation recorded by thermochronological data in the Massif Central 100-130 Ma ago (Barbarand et al 2001(Barbarand et al , 2020Peyaud et al 2005 Our U-Pb dataset and geochronological data from previous authors testify to a major deformation event in the intraplate domain during the Albian, as recorded in the Causses domain area at that time by the formation of normal faults, according to Parizot et al (2020). We propose that this event could be a consequence of the opening of the Pyrenean basins to the south in Lower Cretaceous times (Choukroune et al 1973).…”

“…Distinction between these two tectonic phases is, however, not recorded in the intraplate domain to the north, where recent work shows a weak but continuous record of deformation in the Grands Causses area (Fig. 1a) from the Late Cretaceous to the late Eocene (Parizot et al 2020). Regarding the CFS, as well as the Nimes and Durance faults, many authors show reverse-sinistral strike-slip motion during Palaeogene times at the origin of elevated horsts such as the Jurassic Thaurac plateau (between Ganges and Saint-Bauzillede-Putois; Fig.…”

When did the Pyrenean shortening end? Insight from U–Pb geochronology of syn‐faulting calcite (Corbières area, France)

“…In this study, we complete the geodynamic absolute timetable of the northern Pyrenean foreland based on the combination of inversion of fault slip data (fault planes and associated calcite slickenfibres) and absolute dating of these brittle tectonic structures through in situ U–Pb geochronology of syn‐faulting calcite fibres (Beaudoin et al., 2018; Hansman et al., 2018; Nuriel et al., 2019; Parizot et al., 2020; Roberts et al., 2020). We focus on the Corbières region (northern foreland basin, Figure 1), as, in this area, the lack of Neogene deposits prevents the recognition of any deformation event at that time.…”

Structural Controls on Basin- and Crustal-Scale Fluid Flow and Resulting Mineral Reactions

“…This deformation can potentially result in fluid flow and associated mineralization. In order to better understand the nature, origin, and relative age of intraplate deformation events, Parizot et al [28] analyze examples of the Grands Causses area in the northern foreland basin of the French Pyrenees. This zone was influenced by different neighboring areas, each with their own tectonic evolution.…”