Skip to Main content Skip to Navigation
Journal articles

Thermal interaction of middle and upper crust during gneiss dome formation: Example from the Montagne Noire (French Massif Central)

Abstract : This paper aims to decipher the thermal evolution of the Montagne Noire Axial Zone (MNAZ,southern French Massif Central) gneiss core and its metasedimentary cover through determination ofP–T paths and temperature gradients. Migmatitic gneiss from the core of the dome record a clock-wise evolution culminating at 725 25 °C and 0.8 0.1 GPa with partial melting, followed by adecompression path with only minor cooling to 690 25° C and 0.4 0.1 GPa. Field structuralanalyses as well as detailed petrological observations interpreted in a petrogenetic grid indicate thatthe cover sequence experienced LP-HT metamorphism at <0.4 GPa. Apparent thermal gradientswithin the cover were determined with garnet–biotite thermometry and Raman Spectroscopy on Car-bonaceous Matter. High-temperature apparent gradients (e.g. 530 °C km1 along one transect) areexplained by late brittle–ductile extensional shearing evidenced by phyllonites that post-date peakmetamorphism. In areas where normal faults are less abundant and closely spaced, gradients of 20to 50 °C km1 are calculated. These gradients can be accounted for by a combination of domeemplacement and ductile shearing (collapse of isotherms), without additional heat input. Finally, thethermal evolution of the MNAZ is typical for many gneiss domes worldwide as well as with otherLP-HT terranes in the Variscides.
Complete list of metadata

Cited literature [69 references]  Display  Hide  Download

https://hal-insu.archives-ouvertes.fr/insu-01290388
Contributor : Nathalie POTHIER Connect in order to contact the contributor
Submitted on : Tuesday, May 17, 2016 - 10:00:31 AM
Last modification on : Friday, August 5, 2022 - 10:55:22 AM
Long-term archiving on: : Thursday, August 18, 2016 - 10:21:28 AM

File

jmg12188.pdf
Files produced by the author(s)

Licence


Distributed under a Creative Commons Attribution - NonCommercial - NoDerivatives 4.0 International License

Identifiers

Citation

Kévin Fréville, Bénédicte Cenki-Tok, Pierre Trap, M. Rabin, A. Leyreloup, et al.. Thermal interaction of middle and upper crust during gneiss dome formation: Example from the Montagne Noire (French Massif Central). Journal of Metamorphic Geology, Wiley-Blackwell, 2016, 34, pp.447-462. ⟨10.1111/jmg.12188⟩. ⟨insu-01290388⟩

Share

Metrics

Record views

308

Files downloads

396