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Tectonic Evolution of the Nevado‐Filábride Complex (Sierra de Los Filábres, Southeastern Spain): Insights From New Structural and Geochronological Data
Author(s) -
Porkoláb Kristóf,
Matenco Liviu,
Hupkes Jasper,
Willingshofer Ernst,
Wijbrans Jan,
Schrojenstein Lantman Hugo,
Hinsbergen Douwe J. J.
Publication year - 2022
Publication title -
tectonics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.465
H-Index - 134
eISSN - 1944-9194
pISSN - 0278-7407
DOI - 10.1029/2021tc006922
Subject(s) - geology , metamorphism , subduction , nappe , ophiolite , shear zone , paleontology , geochemistry , paleogene , fibrous joint , tectonics , structural basin , medicine , anatomy
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 40 Ar/ 39 Ar dating of white micas in structurally critical outcrops of the eastern Sierra de Los Filábres. One older 40 Ar/ 39 Ar age population (38–27 Ma) is found at distance from the main shear zones in the relics of an early foliation, while a younger 40 Ar/ 39 Ar 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.