Nature and impact of the Neotectonic deformation in the western Sierra Nevada (Spain)

The current high relief of the western sector of the Sierra Nevada was practically nonexistent before the Tortonian, as attested by the marine Late Neogene outcrops that reach a height of 1830 m, which would easily surpass 2000 m if not for erosion. The significant uplift produced, over 3500 m, has caused considerable thinning, detachments and gravitational slides in the Alpujarride units. The general displacements of these movements are towards the WNW to SSW. On the whole, the morphology is fan-like, adapting itself to the border of the Sierra Nevada. This border contains normal conjugate NW–SE and N–S to NNE–SSW faults, the latter also with sinistral strike–slip character. These faults have accommodated the uplift of the Sierra Nevada within an almost N–S compressive context and linked E–W extension. This sector coincides with the western boundary of the Nevado-Filabride complex and, in its southern continuation, with the western limit of the lower Alpujarride units, seeming to indicate a fault (or faults) reaching deep into the basement. Uplift has taken place unevenly over the last few million years, with three noteworthy periods: during the deposition of the Block Formation in the Late Tortonian, towards the Early?–Middle Pleistocene, and in the Middle?–Late Pleistocene. This has resulted in considerable deepening of the fluvial net surrounding Sierra Nevada at the present time.