Abstract

Stratigraphic and sedimentological analysis of the Granada and Guadix basins establishes the time when they became distinct (Upper Tortonian) and their different phases of evolution, up to the entrenchment of the present fluvial network during the Holocene. Six depositional sequences have been differentiated. These are delimited by major unconformities, representing tectonic and/or eustatic events. 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 remaining three (post-Tortonian) correspond to the continental infilling.

Introduction

The Granada and Guadix basins are intramontane basins developed during and after the Upper Miocene, after westward displacement of the Alboran realm had ceased (Sanz de Galdeano & Vera, 1992). The presence of the remains of Lower and Middle Miocene marine materials on the basement suggests that these and other basins were superimposed on what was a sedimentation area which, from its inception and throughout its evolution, played a part in the geological history of the Alboran basin. The sedimentary cover recognized on the basement of the Alboran basin (Comas et al., 1992), which characterizes the sedimentary infilling of the Betic and Rifian Neogene basins, allows us to visualize a more or less continuous sedimentary deposition during part of the Neogene in an ‘ancient Alboran basin’.