Estructura de la Sierra de Lújar (Complejo Alpujárride, Cordillera Bética)

The Sierra de Lujar constitutes one of the best examples of fold superposition of the Internal Zone of the Betic Cordillera (S Spain). In this paper, the members of its Triassic carbonate series have been used for the first time to obtain the cartography of the Sierra de Lujar, providing knowledge of the two folding systems, the older trending E-W and the younger (far better represented), NNE-SSW. The most important fold is a large reverse syncline with a convex axis towards the SE, forming part of the S and E edges of this sierra; contrarily, the vergence is towards the N in the southern sector and towards the W in the eastern sector. The interior of the Sierra de Lujar bears a succession of NNE-SSO anticlinal and synclinal folds, some with reverse limbs. The vergences fluctuate, even within the same fold. Folds of an E-W system crop out only in the SW sector of the Sierra de Lujar and verge to the S. The unit of the Sierra de Lujar (Lujar-Gador unit) is overthrust by the Escalate unit (which is a duplication of the Lujar unit) and by other upper units, formed here by schists. The W edge of the Sierra de Lujar is affected by a large normal fault that sinks the Escalate unit there. The E-W folds were coetaneous with the thrusting of the units, while those in the NNE-SSW direction formed at the onset of the westward shift of the Internal Betic-Rif Zone.