The E-W segments of the contact between the external and internal zones of the Betic and Rif cordilleras and the E-W corridors of the internal zone (a combined explanation)

C. Sanz de Galdeano

doi:10.3989/egeol.96523-4260

Abstract

The contact between the Internal Betic-Rif Zone and the corresponding external zones is not regular, sorne sections having a NNE-SSW direction and others approximately EW. These latter coincide with sorne of the corridors of the Internal Zone, and have continuity with those within this zone. A model which relates the two features is proposed, in which the corridors originally corresponds to faults or fault zones which are the eastern continuation of the transcurrent contacts, by means of which the Internal Zone advanced westwardly more easily on its collision with the External Betic Zone. This means that the Internal Zone is divided into various cortical segments and advanced towards the west. The proposal of the model ineludes a discussion of the Alpujarras and Colmenar corridors, which continue each other, and provides values for the displacement of the zone of faults. With this model, both the transcurrent E-W fauits of the Internal Zone, as well as at least part of the extensional movements affecting this zone, remain subordinate to the shifting of the Internal Zone towards the west.

Highlights

Numerous articles treat the emplaeement of the Betic-Rif internal Zone in its eurrent position
Two fundamental types of models are proposed: A) those which indicate that the Internal Zone was deformed and metamorphosed praetical1y in the same place as it is found at present, and afterwards rose, sliding gravitationally to deform the Betie and Rif External zones and ereate the Gibraltar Are (Weijermars, 1987; Doblas and Oyarzun, 1989; Platt and Vissers, 1989); and B) those which assume a major shift of the Internal Zone towards the W, after having been deformed and metamorphosed itself in more easterIy seetors of the western Mediterranean
Docherty and Banda (1995) indicate that «while the deformation front of the Alboran Domain migrated westwards, subsidence in the Alboran Sea basin propagated in the opposite direction, east/southeastward»

Summary

Introduction

Numerous articles treat the emplaeement of the Betic-Rif internal Zone (lnternal Zone) in its eurrent position. 1971; Durand Delga, 1980; Durand Delga and Fontboté, 1980; Wildi, 1983; Sanz de Galdeano , 1983 and 1990a; Sauz de Galdeano and Vera, 1992; etc.) This movement would be partially connected to the formation of oceanic basins in the western Mediterranean (especially with the Argelo-Provencal) which gave rise to , among other features, the eastward displacement of Corsica and Sardinia and the southward displacement of Kabylias. This phenomenon would be tectonically parallel (but not contemporary) with the eastward expu1sion of the Apennines and the Calabrian Are, coeval with the formation of the Tyrrhenian Sea. The expulsion of the Betic-Rif Zone could be connected with the process of subduction proposed by Boillot et al (1984), among other authors. Docherty and Banda (1995) indicate that «while the deformation front of the Alboran Domain migrated westwards, subsidence in the Alboran Sea basin propagated in the opposite direction, east/southeastward»

Objectives

Discussion

Conclusion