Late Cenozoic landscape development and its tectonic implications for the Guadalhorce valley near Álora (Southern Spain)

Abstract

Landscape evolution is the result of a variety of geomorphological processes and their controls in time. In southern Spain tectonics, climate and sea-level fluctuations have been some of the main variables controlling long-term (Late Cenozoic) landscape evolution. In the Guadalhorce valley, Malaga, geomorphological reconstructions can be undertaken using sedimentary evidence from marine and fluvial deposits as well as erosional evidence such as terrain form and longitudinal profile analysis. Data are obtained and analysed from the Upper Miocene to present. These allow reconstructions which add information and constraints to the uplift history and landscape development of the area. Main sedimentation phases are the Late Tortonian, Early Pliocene and Pleistocene. Important erosional hiatus are found for the Middle Miocene, Messinian and Late Pliocene to Early Pleistocene. These phases of erosion and sedimentation resulted in a relative large and elongated Tortonian marine valley filled with complex sedimentary structures. Next, a prolonged stage of erosion of these deposits and incision of the major valley system took place during the Messinian. In the Pliocene, a short palaeo-Guadalhorce, in a narrow and much smaller valley existed. This valley was partly filled with marine sediments and prograding fan delta complexes. During the Pleistocene, a wider and larger incising river system resulted in rearrangements of the drainage network. Evaluating the uplift history of the area, we found that rates of tectonic activity were higher during the Tortonian–Messinian and Upper Pleistocene, while tectonic activity was lower during the Pliocene. Relative uplift rates for the study area range for the Messinian between 160 and 276 m Ma −1, for the Pliocene between 10 and 15 m Ma −1 and for the Pleistocene between 40 and 100 m Ma −1.