Quaternary palaeohydrological evolution of a playa lake: Salada Mediana, central Ebro Basin, Spain

Sedimentary features, mineralogy, bulk geochemical composition, stable isot ope analyses and pollen data from sediment cores were used to reconstruct t he Late Quaternary depositional evolution of the Salada Mediana playa lake (central Ebro Basin, northeastern Spain). The 150-cm-long sediment core seq uence is composed of gypsum- and dolomite-rich muds (Lower and Middle secti ons) and black, laminated, calcite-bearing sediments (Upper section). The S alada Mediana formed as a karstic depression in the Miocene gypsum substrat um during the Late Pleistocene. The Lower section was deposited in a sulpha te-carbonate saline lake that ended with a period of desiccation and basin floor deflation. Subsequent deposition (Middle section) took place in a pla ya-lake system. Two cycles of lower water table and expanded saline mud fla ts occurred. The Holocene sequence is missing, probably as a result of aeol ian erosion. Sedimentation resumed only a few centuries ago, and saline pan environments dominated until modern times. The Salada Mediana facies succe ssion was mainly governed by fluctuations in the hydrological balance, brin e composition, and salinity; however, aeolian processes (detrital input and deflation) and recycling of previously precipitated salts also played a si gnificant role.