Laguna Fuente de Piedra: An example of a dolomite factory recording ~50,000 years of depositional and paleoclimatic evolution

Abstract

We examine the depositional dynamics and paleoclimatic significance of the evaporite–dolomite association in Laguna Fuente de Piedra (LFP), a modern sa- line, endorheic playa lake system in southern Spain. This study presents results from a multidisciplinary approach, examining the two longest continuous sedi- ment cores retrieved from the basin. One core was drilled in the Salina area, lo- cated in the eastern part of the basin, which represents the zone that dries last and is referred to as the Salina core (14.4 m). The second core, Las Latas (46.2 m), was retrieved from the southwestern part of the basin, which is the zone that dries first. This study characterises carbonate minerals and their precipitation mechanism in the sediments from these two cores over the past ~50,000 years. Six major lithofacies were identified based on variations in mineralogy (carbon- ates, sulphates and siliciclastic minerals) and sedimentary patterns. Observed shifts in the depositional environment are hypothesised to result from changes in the hydrological balance, which in turn is controlled by paleoclimatic evo- lution. During dry and cold periods, the basin experienced higher evaporation rates, leading to the deposition of evaporites along with dolomite in a continental sabkha environment with ephemeral floods. These arid conditions favoured large production of endogenic sulphates and carbonates (dolomite) and reduced clastic input. In contrast, wetter periods were characterised by increased clastic influx and the precipitation of calcite–aragonite facies, in a shallow ephemeral to per- manent lake, mostly during the Pleistocene–Holocene transition, continuing into the Holocene. These findings show the high sensitivity of shallow continental sedimentary systems to climate variations and provide information on significant short-lived climatic events, tentatively correlated with Heinrich events, in the western Mediterranean region.