The missing piece – New insights to comprehend enigmatic Miocene palaeoceanography of the Mediterranean Sea using the Nd isotopic record

Abstract

The evolution of the Mediterranean-Paratethys marine system during the Miocene represents one of the crucial milestones in the Earth's oceans history. It fundamentally affected the climate evolution not just in Europe and the adjacent continents, but also on a global scale. The progressive transition of the Mediterranean-Paratethys system from a latitudinal marine domain connecting two main Earth's oceans to a modern-day enclosed setting happened mainly from the Burdigalian (∼16–18 Ma) to Serravallian period (∼13.8–12.6 Ma). It triggered a complex interplay of palaeoceanographic events such as overturns in water circulation regimes that affected the large-scale palaeoclimatic settings. Here, we present 3D palaeoceanographic models from the late Burdigalian to the Serravallian that are based on a comprehensive 143Nd/144Nd dataset containing 59 individual measurements. Our results imply that the first indications of separation between the western and eastern parts of the Mediterranean occurred during the late Langhian (∼16–13.8 Ma) and were linked to the pronounced circulation overturn. The modern-day setting with the characteristic εNd signatures for the Western and Eastern Mediterranean developed during the Serravallian. Altogether, our set of models demonstrates the dynamics of the two-step closure of the Indian-Atlantic gateway and the palaeoceanographic evolution of this area during the middle Miocene.