RT Journal Article
T1 P-T evolution of HP migmatitic paragneiss from the Beni Bousera metamorphic unit (internal Rif, Northern Morocco) constrained by phase equilibria modelling and melt reintegration
A1 Essoualeh, Oumaima
A1 Aghzer, Abdel Mouhsine
A1 Afiri, Abdelkhaleq
A1 Abati Gómez, Jacobo
A1 El Mostadi, Abdelfettah
A1 Benchekroun, Fouad
AB The high-pressure (HP) migmatitic paragneiss of the Beni Bousera metamorphic unit (BBMU) from the Beni Bousera Massif underwent granulite-facies metamorphism. They mainly consist of garnet, biotite, kyanite, sillimanite, cordierite, spinel, quartz, plagioclase, K-feldspar, rutile, ilmenite and graphite. These minerals form a sequence of metamorphic assemblages corresponding to five metamorphic events (M1, M2, M3, M4, and M5). The first three events correspond to a latest Carboniferous-earliest Permian metamorphic evolution, while the last two are retrograde and Alpine in age. The p-T conditions of these metamorphic events were estimated using pseudosection calculations in the MnNCKFMASTHO system. Following prograde stage conditions of 9.3–10.9 kbar and 630–665°C (M1 stage), the p-T evolution culminates in melting of the paragneiss which occurred mainly at HP conditions, within the kyanite stability field, at 11.8–14.2 kbar and 820–845°C (M2 pressure-peak); anatexis then continued at high to medium pressure (HMP), within the sillimanite stability field, at 9.9–11 Kbar and 840–860°C (M3 thermal-peak), accompanied by the production of very small proportions of melt. The prograde p-T segment of the inferred clockwise path is characterized by a pressurization related to a post-Variscan collisional event triggered by the closure of the Paleotethys Ocean, and is followed by the exhumation of the granulitic unit to mid-crustal depth, with slight coeval heating. The retrograde Alpine evolution is coeval with the final exhumation of the migmatitic paragneiss and underlying peridotites during back-arc extension related to the westward retreat of the Alpine subduction. It occurred under sub-solidus conditions from 9.5–10.7 kbar and 818–848°C (M4) to 4.9–5.85 kbar and 710–785°C (M5) and corresponds to a near-isothermal and strongly decompressive metamorphic evolution (ΔP ≈ 5 Kbar).
PB Taylor and Francis
SN 0020-6814
YR 2024
FD 2024-08-20
LK https://hdl.handle.net/20.500.14352/119229
UL https://hdl.handle.net/20.500.14352/119229
LA eng
NO Essoualeh, O., Aghzer, A., Afiri, A., Abati, J., Mostadi, A. E., & Benchekroun, F. (2025). P-T evolution of HP migmatitic paragneiss from the Beni Bousera metamorphic unit (Internal rif, northern morocco) constrained by phase equilibria modelling and melt reintegration. International Geology Review, 67(3), 306-330. https://doi.org/10.1080/00206814.2024.2392248
DS Docta Complutense
RD 8 abr 2025