Thermal evolution of a translithospheric diapir, evidence from a high-pressure granulite (French Massif Central)
Abstract
The Variscan rock record of the French Massif Central (FMC) provides compelling evidence for early Carboniferous crust-mantle interaction during subduction and exhumation of continental high-pressure metamorphic units, but the underlying geodynamic mechanisms remain elusive. The crustal pressure-temperature-time-fluid evolution during this interaction is investigated through a case study of a high-pressure mafic granulite, integrating petrology, phase equilibrium modelling, trace element thermometry, and U-Pb geochronology. Partial replacement of garnet-clinopyroxene-plagioclase-rutile assemblage by amphibole and titanite records hydration and pronounced cooling from ~900-975 • C to ~700-800 • C, under limited decompression from ~13 to 11 kbar. The age of this event is constrained at 354.6 ± 4.6[8.5] Ma by U-Pb dating of titanite. Subsequent ilmenite-clinopyroxene pseudomorphs after titanite indicate further decompression below ~9 kbar. The minimum age of this decompression is given by apatite and rutile U-Pb dates of 348.5 ± 2.6[8.5] Ma and 337.9 ± 1.7[7.0] Ma, respectively. The FMC granulites are associated with mantle rocks, and the inferred P-T conditions compare with those of mantle xenoliths from volcanic regions worldwide, suggesting an interaction with the mantle during exhumation. One-dimensional thermal models of crustal translithospheric diapirs consistently predict cooling in the shallow lithospheric mantle within the ranges 700-1000 • C and 10-15 kbar. Therefore, the peak conditions and subsequent cooling could result from the thermal interaction of a crustal diapir and the mantle. We propose a new petrogenetic model for the FMC where translithospheric diapirs play a central role.
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BibTeX
@article{marien2026thermal,
title = {{Thermal evolution of a translithospheric diapir, evidence from a high-pressure granulite (French Massif Central)}},
author = {Luc de Hoÿm de Marien and Pavla Štípská and Petra Maierová and Pavel Pitra and Karel Schulmann and Andrew Kylander-Clark and Dimitrios Moutzouris and Vít Peřestý and Philippe Yamato and Simon Couzinié and Radek Škoda and Martin Racek and Nikol Novotná and Jonas Vanardois},
journal = {Earth and Planetary Science Letters},
year = {2026},
month = sep,
doi = {10.1016/j.epsl.2026.120333},
url = {https://insu.hal.science/insu-05766646v1},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Thermal evolution of a translithospheric diapir, evidence from a high-pressure granulite (French Massif Central)
AU - Luc de Hoÿm de Marien
AU - Pavla Štípská
AU - Petra Maierová
AU - Pavel Pitra
AU - Karel Schulmann
AU - Andrew Kylander-Clark
AU - Dimitrios Moutzouris
AU - Vít Peřestý
AU - Philippe Yamato
AU - Simon Couzinié
AU - Radek Škoda
AU - Martin Racek
AU - Nikol Novotná
AU - Jonas Vanardois
PY - 2026
DA - 2026/09/28
JO - Earth and Planetary Science Letters
DO - 10.1016/j.epsl.2026.120333
UR - https://insu.hal.science/insu-05766646v1
AB - The Variscan rock record of the French Massif Central (FMC) provides compelling evidence for early Carboniferous crust-mantle interaction during subduction and exhumation of continental high-pressure metamorphic units, but the underlying geodynamic mechanisms remain elusive. The crustal pressure-temperature-time-fluid evolution during this interaction is investigated through a case study of a high-pressure mafic granulite, integrating petrology, phase equilibrium modelling, trace element thermometry, and U-Pb geochronology. Partial replacement of garnet-clinopyroxene-plagioclase-rutile assemblage by amphibole and titanite records hydration and pronounced cooling from ~900-975 • C to ~700-800 • C, under limited decompression from ~13 to 11 kbar. The age of this event is constrained at 354.6 ± 4.6[8.5] Ma by U-Pb dating of titanite. Subsequent ilmenite-clinopyroxene pseudomorphs after titanite indicate further decompression below ~9 kbar. The minimum age of this decompression is given by apatite and rutile U-Pb dates of 348.5 ± 2.6[8.5] Ma and 337.9 ± 1.7[7.0] Ma, respectively. The FMC granulites are associated with mantle rocks, and the inferred P-T conditions compare with those of mantle xenoliths from volcanic regions worldwide, suggesting an interaction with the mantle during exhumation. One-dimensional thermal models of crustal translithospheric diapirs consistently predict cooling in the shallow lithospheric mantle within the ranges 700-1000 • C and 10-15 kbar. Therefore, the peak conditions and subsequent cooling could result from the thermal interaction of a crustal diapir and the mantle. We propose a new petrogenetic model for the FMC where translithospheric diapirs play a central role.
SN - 0012-821X
ER -