F. Gonzalezlodeiro et al., SUPERPOSITION OF EXTENSIONAL DETACHMENTS DURING THE NEOGENE IN THE INTERNAL ZONES OF THE BETIC CORDILLERAS, Geologische Rundschau, 85(2), 1996, pp. 350-362
In the internal zones of the Betic cordilleras, extensional structures
have developed from the Upper Oligocene to the present day; they are
contemporaneous with compressional structures (folds and thrusts) in t
he external zones. From the Upper Oligocene to the Aquitanian, extensi
on occurred in the Malaguide/Alpujarride detachment, and related struc
tures show varying kinematics in different sectors. Younger deformatio
ns with a top-to-the-N sense of movement have affected Nevado-Filabrid
e (ductile shear zones), Alpujarride (ductile and brittle shear zones)
and Malaguide rocks (normal faults). At least from the Late Burdigali
an up to the Lower Tortonian, displacements have occurred in the Alpuj
arride/Nevado-Filabride detachment. Deformations have been generally n
on-coaxial, with a top-to-the-W sense of movement. Stretching lineatio
n trends in the Nevado-Filabride rocks curve from E to W suggesting a
progressive variation of the ductile-shear-zone kinematics related to
the Alpujarride/Nevado-Filabride detachment between the Aquitanian and
Lower Tortonian stages. Deformations from the Lower Tortonian to the
present day are normal faults, formed in extensional settings in the u
pper part of the crust, and folds and strike-slip faults which indicat
e NS to NNW-SSE shortening directions and E-W to ENE-WSW extension dir
ections.