Preprints
https://doi.org/10.5194/egusphere-2022-949
https://doi.org/10.5194/egusphere-2022-949
 
20 Sep 2022
20 Sep 2022

Rift thermal inheritance in the SW Alps (France): insights from RSCM thermometry and 1D thermal numerical modelling

Naïm Célini1,2,3, Frédéric Mouthereau2, Abdeltif Lahfid3, Claude Gout1, and Jean-Paul Callot1 Naïm Célini et al.
  • 1Université de Pau et des Pays de l’Adour, E2S UPPA, CNRS, TotalEnergies, LFCR, Pau, France
  • 2Géosciences Environnement Toulouse, Université de Toulouse Paul Sabatier, CNRS, IRD, Toulouse, France
  • 3Bureau des Recherches Géologiques et Minières, Orléans, France

Abstract. Conceptual models of orogenic accretionary prisms assume the increase in peak temperatures (Tmax) towards the internal domains as crustal rocks are accreted from the lower to the upper plate. Yet, the recognition of pre-orogenic heating events in mountain belts questions the magnitude of thermal overprint during nappe stacking. Using Raman Spectroscopy on Carbonaceous Material (RSCM) to calculate Tmax, we have investigated the thermal record of Lower Jurassic to Upper Cretaceous strata exposed along the Digne Nappe, at the front of the SW Alps. Our results highlight two groups of depth-dependent temperatures: (1) a regionally extensive constant Tmax up to 300–330 °C measured in the Jurassic succession and (2) regionally variable lower temperature (<150 °C) recorded either in the upper Mesozoic, the nappe stack or the syn-orogenic sequence. Modelling shows that the highest paleotemperatures were achieved during the Early Cretaceous (~130 Ma), during the Valaisan-Vocontian rifting, while the lowermost ones reflect syn-orogenic burial in the Alpine foreland basin. This study provides a striking new example where mid-crustal paleotemperatures measured in lower plate sediments now accreted at the thrust front are inherited. Estimated peak thermal gradient of 80–90 °C/km requires crustal thickness of ~15 km during the Early Cretaceous, hence placing new constraints for tectonic reconstruction of rift domains and geophysical interpretation of current crustal thickness in the SW Alps. These results call for the careful interpretation of paleothermal data when they are used to identify past collisional events. Where details of basin evolution are lacking high-temperature record may be misinterpreted as syn-orogenic, which can in turn lead to overestimating both orogenic thickening and horizontal displacement in mountain belts.

Journal article(s) based on this preprint

04 Jan 2023
Rift thermal inheritance in the SW Alps (France): insights from RSCM thermometry and 1D thermal numerical modelling
Naïm Célini, Frédéric Mouthereau, Abdeltif Lahfid, Claude Gout, and Jean-Paul Callot
Solid Earth, 14, 1–16, https://doi.org/10.5194/se-14-1-2023,https://doi.org/10.5194/se-14-1-2023, 2023
Short summary

Naïm Célini et al.

Interactive discussion

Status: closed

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on egusphere-2022-949', Anonymous Referee #1, 20 Oct 2022
    • AC1: 'Reply on RC1', Naïm Célini, 25 Nov 2022
  • RC2: 'Comment on egusphere-2022-949', Yann Rolland, 23 Oct 2022
    • AC2: 'Reply on RC2', Naïm Célini, 25 Nov 2022
  • RC3: 'Comment on egusphere-2022-949', Anonymous Referee #3, 24 Oct 2022
    • AC3: 'Reply on RC3', Naïm Célini, 25 Nov 2022

Interactive discussion

Status: closed

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on egusphere-2022-949', Anonymous Referee #1, 20 Oct 2022
    • AC1: 'Reply on RC1', Naïm Célini, 25 Nov 2022
  • RC2: 'Comment on egusphere-2022-949', Yann Rolland, 23 Oct 2022
    • AC2: 'Reply on RC2', Naïm Célini, 25 Nov 2022
  • RC3: 'Comment on egusphere-2022-949', Anonymous Referee #3, 24 Oct 2022
    • AC3: 'Reply on RC3', Naïm Célini, 25 Nov 2022

Peer review completion

AR: Author's response | RR: Referee report | ED: Editor decision
AR by Naïm Célini on behalf of the Authors (25 Nov 2022)  Author's response    Author's tracked changes    Manuscript
ED: Publish subject to minor revisions (review by editor) (28 Nov 2022) by Stefano Tavani
AR by Naïm Célini on behalf of the Authors (01 Dec 2022)  Author's response    Author's tracked changes    Manuscript
ED: Publish subject to minor revisions (review by editor) (02 Dec 2022) by Stefano Tavani
AR by Naïm Célini on behalf of the Authors (07 Dec 2022)  Author's response    Author's tracked changes    Manuscript
ED: Publish as is (08 Dec 2022) by Stefano Tavani
ED: Publish as is (09 Dec 2022) by Federico Rossetti(Executive Editor)

Journal article(s) based on this preprint

04 Jan 2023
Rift thermal inheritance in the SW Alps (France): insights from RSCM thermometry and 1D thermal numerical modelling
Naïm Célini, Frédéric Mouthereau, Abdeltif Lahfid, Claude Gout, and Jean-Paul Callot
Solid Earth, 14, 1–16, https://doi.org/10.5194/se-14-1-2023,https://doi.org/10.5194/se-14-1-2023, 2023
Short summary

Naïm Célini et al.

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The requested preprint has a corresponding peer-reviewed final revised paper. You are encouraged to refer to the final revised version.

Short summary
We investigate the peak temperature of sedimentary rocks of the SW Alps (France), using the Raman Spectroscopy on Carbonaceous Material. This method provides an estimate of the peak temperature achieved by organic-rich rocks. To determine the timing and the tectonic context at the origin of these temperatures we use 1D thermal modelling. We find that the high temperatures up to 300 °C were achieved during pre-collisional extensional events, not during tectonic burial in the Western Alps.