S7 - Pliocene–Pleistocene continental infilling of the Granada and Guadix basins (Betic Cordillera, Spain): the influence of allocyclic and autocyclic processes on the resultant stratigraphic organization

Summary

Abstract

The stratigraphic architecture of the continental infilling is the result of the stacking of three depositional sequences, controlled by tectonics and climate that affected the relief of the margins, and by subsidence and by variations of the general base level. Each depositional sequence arises out of a complex interrelation between several depositional systems (the longitudinal system, coinciding with the axis of the basin and the areas of lacustrine sedimentation, and the transverse systems), and its sequential organization depends on the dynamic behaviour of the different depositional systems and on the fluctuations in base level (lake level).

Introduction

The Granada and Guadix basins are intramontane basins that became distinct from each other towards the Late Miocene, after westward displacement of the Alboran realm had ceased (Sanz de Galdeano & Vera, 1992). They are located in the central sector of the Betic Cordillera, lying on the contact between the Internal and External Zones (see Fig. 1 in Chapter S6). The northwestern half of the basement is therefore made up of Mesozoic and Tertiary materials from the External Zones, while the southeastern half consists of Palaeozoic and Triassic materials from the metamorphic complexes of the Internal Zones.

Six depositional sequences (see Fig. 4 in Chapter S6) have been distinguished in the sedimentary infilling (see Chapter S6). The two oldest sequences (Tortonian) correspond to infilling during the phase of marine sedimentation, the third (uppermost Tortonian) corresponds to the marine-continental transition, and the three remaining sequences (post-Tortonian) correspond exclusively to the continental infilling.