La altiplanicie kárstica de la Sierra de Segura: el mayor torcal de la Cordillera Bética

Laburpena

The hydrological divide of the upper basins of the Guadalquivir and Segura rivers coincides with an extensive mountainous area, about 100 km long: the Sierra de Segura. From the geological point of view it belongs to the Inner Prebético domain of the Betic Cordillera, characterized by a thick sequence of, mainly, marine sedimentary rocks (limestones, dolomites, marls, sandstones and lutites). These materials were deformed during the alpine orogeny, which, in addition, produced the emersion of the region about 10 Ma ago. Shortly after, in a period of relative stability, a planation surface had to be formed due to the action of diverse erosive processes, including karstification. Since then the region has undergone a continuous uplift, at rates of 0,2 mm/y, responsible for the paleosurface is located at about 1700 m altitude. Simultaneously, there has been a deep entrenchment of the main fluvial network and a progressive erosion of the paleosurface, especially on the left watershed of the Segura River, where it has been reduced to a series of isolated fragments that are locally known as “calares” “ At present more than 800 km2 of the Segura plateau are preserved, where an extraordinary karstic morphology has developed. Dolines are the most abundant and characteristic karstic forms of the Sierra de Segura (more than 3000 have been inventoried). Practically all sinkholes are on the paleosurface, especially in the western strip, which receives considerably more abundant precipitation. In short, the development of exokarstic morphology is not only conditioned by geological factors, such as lithology and the structure of materials, but also climatic and topographic factors intervene