Chronology and integrated stratigraphy of the Miocene Sinj Basin (Dinaride Lake System, Croatia)

In the Miocene, the intra-montane basins of the Dinaric Mountain Chain harbored a series of long-lived lakes constituting the so-called Dinaride Lake System. The thick lacustrine sedimentary records of these lakes provide an excellent opportunity to study evolution and radiation of mollusks in an isolated environment. The 500 m thick infill that accumulated in the Sinj Basin is one of the key records because of its excellent mollusk preservation. Recent studies on the depositional history, pollen assemblages and large mammals have enhanced the understanding not only of Lake Sinj, but also of the regional climatic developments and faunal migratory patterns. A reliable chronology of the development of Lake Sinj, which is crucial for global correlation of its endemic realm, was still lacking. In this paper we present a detailed time-frame for the Miocene Sinj basin based on palaeomagnetic and ⁴⁰Ar/³⁹Ar data. We conclude that deposition took place between 18.0 to 15.0 Ma, a time span that correlates with the upper Burdigalian and lower Langhian Mediterranean stages and Ottnangian, Karpatian and lowermost Badenian Paratethys stages. Furthermore, we determined the timing of several events in mollusk evolution, important for correlation across the Dinarides. An age of 15.0 Ma is attributed to the large mammals Conohyus and Gomphotherium, preserved in the upper part of the basin stratigraphy.