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Dating the pre-Middle Ordovician metavolcanic rocks and metagranites of the Ollo de Sapo Domain has, historically, been difficult because of the small compositional variation, the effects of the Variscan orogeny and, as revealed in this paper, the unusually high fraction of inherited zircon components. The first reliable zircon data (U-Pb ion microprobe and Pb-Pb stepwise evaporation) indicate that the Ollo de Sapo volcanism spanned 495 [+ or -] 5 Ma to 483 [+ or -] 3 Ma, and was followed by the intrusion of high-level granites from 483 [+ or -] 3 Ma to 474 [+ or -] 4 Ma. In both metavolcanic rocks and metagranites, no less than 70-80% of zircon grains are either totally Precambrian or contain a Precambrian core overgrown by a Cambro-Ordovician rim. About 80-90% of inherited zircons are Early Ediacaran (602-614 Ma) and derived from calc-alkaline intermediate to felsic igneous rocks generated at the end of the Pan-African arc--continent collision. In the Villadepera region, located to the west, both the metagranites and metavolcanic rocks also contain Meso-Archaean zircons (3.0-3.2 Ga) which ultimately originated from the West African Craton. In the Hiendelaencina region, located to the east, both the metagranites and metavolcanic rocks lack Meso-Archaean zircons, but they have two different inherited zircon populations, one Cryogenian (650-700 Ma) and the other Tonian (850-900 Ma), which suggest older-than-Ediacaran additional island-arc components. The different proportion of source components and the marked variation of the [sup.87]Sr/[sup.86][Sr.sub.init.] suggest, at least tentatively, that the across-arc polarity of the remnants of the Pan-African arc of Iberia trended east-west (with respect to the current coordinates) during Cambro-Ordovician times, and that the passive margin was situated to the west. Keywords: magmatism, Ordovician, zircon, dating, U/Pb, Pb/Pb.

The Malaguide Complex of the Betic Cordillera represents a tectonic element which mostly underwent brittle deformation during the Alpine orogeny, and that covers the high-pressure/low-temperature (HP/LT) complexes of the internal Betic Cordillera. The evolution of this complex can help to determine both when the lower HP/LT complexes began to exhume and the behavior of the upper plate during this process. Moreover, this complex is a key element to understanding the relationships between the late orogenic extension in the internal Betic Cordillera and the coeval compression in the External Zones of the same mountain chain. This paper focuses in the geometry and kinematics of the Alpine structures of this Malaguide Complex in the eastern Betic Cordillera, near the village of Velez Rubio. We propose that these Alpine structures can be grouped into three main stages. First stage (Paleogene) began with a synmetamorphic slaty cleavage produced in anchizone conditions. This foliation is associated with northward vergent structures and was probably connected with the superposition of the Malaguide Complex over the Alpujarride during the middle Eocene. This first stage ended with the thinning of the Malaguide Complex (Oligocene) by an extensional detachment with a top-to-the-NNW sense of movement. Second stage records the convergence of the External and Internal Zones during the Aquitanian-Burdigalian. This convergence was a right-lateral transpression that produced back thrusts and extensional structures that exhumed the HP/LT rocks of the Alpujarride Complex. Third stage corresponds to the evolution from the late Burdigalian to the present-day, when the Internal and External zones were welded together. doi:10.1029/2006TC002019.

In the Central Iberian Zone there are several large thermal domes in which small bodies of ultramafic, mafic and intermediate rocks appear intimately associated with crustal granites and migmatites. The closest spatial association between the ultramafic, mafic and intermediate rocks and migmatites is in the Toledo Anatectic Complex, where field relationships suggest that these rocks are coeval and have an age close to 340 Ma. This, and the recent discovery in the neighbouring Ossa Morena Zone of a large mid-crustal seismic reflector interpreted as a 335-350 Ma mafic sill, reinforce the hypothesis that heat for crustal melting was supplied from early Variscan mantle magmas emplaced in the middle crust. However, precise ion-microprobe U--Pb zircon dating and Ti-in-zircon thermometry in Toledo do not support this idea. Whereas the mean age of four mafic bodies is 307 [+ or -] 2 Ma, the migmatites are c. 25 Ma older. The migmatites hosting ultramafic, mafic and intermediate bodies have the same age and Ti-in-zircon temperatures as migmatites far from any mafic intrusion. These data reveal that ultramafic, mafic and intermediate magmas are late Variscan; they were emplaced in already cooling anatectic zones once the extensional collapse was initiated, and their thermal impact on the mid-crustal Variscan anatexis of Central Iberia was negligible.

Seismic reflection, magnetometric, and gravimetric data allow the study of main features of crustal structure of the central sector of the Betic Cordillera, southeast Spain. The region shows a slightly thickened crust with an abrupt transition to the thin crust of the Alboran Sea along an E-W oriented narrow band, subparallel to the coast line. In the External Zones, compressive deformation was caused by the Neogene evolution of the mountain chain. Faulting dominated the Internal Zones up to the Quaternary. A geological model explains the recent evolution of crustal deformation.

The Recent and present-day stress state in the southeastern area of the Granada Basin and surrounding regions was analyzed, based on a combined study of the earthquake focal properties and paleostresses determined from Recent structures. Seismicity in the area is focused in the upper crust to a depth of 14-16 km in the southeastern Granada Basin, reaching up to 25 km to the SW. The majority of the activity is expected to be produced by high-angle and detachment faults. The Granada Basin crust appears to have undergone uplift since the Tornonian.