Middle to Upper Miocene benthonic foraminiferal palaeoecology of the Tap Marls (Alicante Province, SE Spain) and its palaeoceanographic implications

The benthonic foraminiferal faunas of twenty sections have been analysed statistically (cluster analysis) and interpreted palaeoecologically. The analysis shows that oxygenation was the most important factor for the distribution of the faunas in the investigated area. The lifting and lowering of the sill to the Atlantic Ocean (Gibraltar sill), in conjunction with climatic changes and sea level fluctuations, led to changes in the current system and to two faunal turnovers at the transition from Langhian to Serravallian (∼15.2–15.0 Ma) and at the end of the Serravallian, respectively (∼11.7–11.4 Ma). The faunas indicate well oxygenated (Langhian), reduced oxygenated (Serravallian) and again well oxygenated (Tortonian) conditions. A simplified circulation model for the western Mediterranean, based on the authorʹs interpretation and additional sources, suggests: (a) an estuarine circulation during the Langhian; (b) a `restrictedʹ anti-estuarine pattern with sluggish circulation until the end of the Serravallian; and (c) an anti-estuarine circulation similar to todayʹs situation during the Tortonian.