Gallocanta Saline Lake, Iberian Chain

Abstract

Gallocanta Lake, covering 14.5 km², is the greatest ephemeral saline lake in Europe. It is located in the Iberian Chain, NE Spain, in the bottom of a karst polje. The Gallocanta saline lake formed once Jurassic limestones were almost completely corroded, and the floor of the depression was underlain by Triassic clays and evaporites. The late Quaternary evolution of the lake can be reconstructed from the deposits underlying the lake bottom and from different levels of lacustrine terraces located in its downwind side. Different phases of flooding and desiccation can be deduced from both sources of data. The current dynamics of the lake is controlled by water-level fluctuations and wind action. Wind-driven waves and longshore currents transport sediments to the downwind zone and generate barrier islands, spits and submerged bars, with a dynamic behaviour very similar to that of marine coastal environments. Lake segmentation due to cuspate foreland growth has divided the original lake into minor ones. Segmentation is still active at present and tends to isolate a minor lacustrine body. Progressively decreasing rainfall, together with sediment supply to the lake, enhanced by extensive agricultural practices in the basin, have frequently led to lake desiccation over the last decades. Extensive polygonal soils and salt crusts cover the bottom during drying-up periods.