TY - JOUR
T1 - Tectonic Evolution of the Nevado-Filábride Complex (Sierra de Los Filábres, Southeastern Spain)
T2 - Insights From New Structural and Geochronological Data
AU - Porkoláb, Kristóf
AU - Matenco, Liviu
AU - Hupkes, Jasper
AU - Willingshofer, Ernst
AU - Wijbrans, Jan
AU - van Schrojenstein Lantman, Hugo
AU - van Hinsbergen, Douwe J. J.
N1 - Funding Information:
The research presented in this paper was funded by the European Union's MSCA‐ITN‐ETN Project SUBITOP 674899. Hans de Bresser and Frits Hilgen are gratefully acknowledged for their field introduction to the geological world of the Betics. Guillermo Booth‐Rea, Patrick Monié, and Romain Augier are gratefully acknowledged for their constructive suggestions that have greatly improved the original manuscript.
Publisher Copyright:
© Wiley Periodicals LLC. The Authors.
PY - 2022/8
Y1 - 2022/8
N2 - The high-pressure metamorphic Nevado-Filábride Complex (NFC) in the Betics mountain range of southeastern Spain exhibits continental and ocean-derived tectonic units, which are key for understanding the geodynamic evolution of the Western Mediterranean. We address the current debate in the definition of tectonic units, the emplacement of (ultra)mafic rocks, and the timing of burial metamorphism by conducting a structural study combined with single grain fusion 40Ar/39Ar dating of white micas in structurally critical outcrops of the eastern Sierra de Los Filábres. One older 40Ar/39Ar age population (38?27 Ma) is found at distance from the main shear zones in the relics of an early foliation, while a younger 40Ar/39Ar population (22?12 Ma) is dominant in the vicinity of these shear zones, where the early foliation is obliterated. Both age groups are interpreted as the record of deformation or fluid-induced recrystallization during distinct fabric-forming events, while alternative scenarios are discussed. A key observation is the presence of an ophiolitic mélange, which?together with new and published geochronological data?allows for a new tectonic hypothesis. This considers Paleogene subduction beneath a Jurassic oceanic lithosphere, followed by the continued subduction of NFC and overlying ophiolites below the Alpujárride Complex. Exhumation during westward slab roll-back led to the formation of an extensional detachment system that obliquely cut nappe contacts. Although the timing constraints for high pressure-low temperature (HP-LT) metamorphism in the NFC remain inconclusive, the new tectonic hypothesis provides a solution that can account for both Paleogene and Miocene ages of HP-LT metamorphism.
AB - The high-pressure metamorphic Nevado-Filábride Complex (NFC) in the Betics mountain range of southeastern Spain exhibits continental and ocean-derived tectonic units, which are key for understanding the geodynamic evolution of the Western Mediterranean. We address the current debate in the definition of tectonic units, the emplacement of (ultra)mafic rocks, and the timing of burial metamorphism by conducting a structural study combined with single grain fusion 40Ar/39Ar dating of white micas in structurally critical outcrops of the eastern Sierra de Los Filábres. One older 40Ar/39Ar age population (38?27 Ma) is found at distance from the main shear zones in the relics of an early foliation, while a younger 40Ar/39Ar population (22?12 Ma) is dominant in the vicinity of these shear zones, where the early foliation is obliterated. Both age groups are interpreted as the record of deformation or fluid-induced recrystallization during distinct fabric-forming events, while alternative scenarios are discussed. A key observation is the presence of an ophiolitic mélange, which?together with new and published geochronological data?allows for a new tectonic hypothesis. This considers Paleogene subduction beneath a Jurassic oceanic lithosphere, followed by the continued subduction of NFC and overlying ophiolites below the Alpujárride Complex. Exhumation during westward slab roll-back led to the formation of an extensional detachment system that obliquely cut nappe contacts. Although the timing constraints for high pressure-low temperature (HP-LT) metamorphism in the NFC remain inconclusive, the new tectonic hypothesis provides a solution that can account for both Paleogene and Miocene ages of HP-LT metamorphism.
KW - burial-exhumation processes
KW - Nevado-Filábride Complex
KW - Ar/Ar dating
KW - structural analysis
KW - ophiolite obduction
KW - paleogeographic reconstruction
UR - http://www.scopus.com/inward/record.url?scp=85136888626&partnerID=8YFLogxK
U2 - 10.1029/2021TC006922
DO - 10.1029/2021TC006922
M3 - Article
SN - 0278-7407
VL - 41
SP - 1
EP - 27
JO - Tectonics
JF - Tectonics
IS - 8
M1 - e2021TC006922
ER -