Structurally controlled drainage basin development in the south of Menorca (Western Mediterranean, Spain)

The south of Menorca consists of a gently folded Upper Miocene carbonate platform over which a drainage system has developed. Three areas with different drainage characteristics have been delimited: the central area, the eastern area and the western area. The central area is characterised by deep streams with steep slopes, whereas the western and eastern areas have slightly incised streams with gentle slopes. The drainage development has been controlled by the inversion of a normal fault in Pliocene times, resulting in a wide anticline with a NNE–SSW orientation. The deep streams of the central area follow the faults associated with this anticline. The amount of incision achieved by these streams depends on the proportion of impermeable rocks exposed in the drainage basin. The streams draining basins with a large proportion of impervious rocks have concave longitudinal profiles, whereas those from catchments with a smaller area of impermeable materials have concave–convex profiles. Streams with minor incision are found in the western and eastern areas of the carbonate platform given that their drainage basins are constituted by permeable materials.