Miocene Oceanographic Evolution Based on the Sr and Nd Isotope Record of the Central Mediterranean

Abstract

The Miocene is a key interval in the geodynamic and oceanographic evolution of the Mediterranean marking the transition from a wide open basin to the modern closed basin. We used the Sr and Nd isotope records of two Miocene carbonate successions in the Adriatic to document that the evolution of the Mediterranean Basin controlled its seawater chemistry. During the late Aquitanian (~21 Ma), a time of glaciation and sea level lowstand, increased runoff affected the Sr isotope ratios of Mediterranean waters, whereas during the Burdigalian (20.44–15.97 Ma) volcanism in the circum‐Mediterranean area mainly influenced the Sr isotopic signature. During the Langhian (15.97–13.82 Ma), a time of sea level highstand associated with the Middle Miocene Climatic Optimum, the Nd isotope values indicate that waters exchanged between the Paratethys and the Central Mediterranean. The Central Mediterranean was well connected with the Atlantic Ocean between the Langhian and the early Tortonian (15.97–11.5 Ma), but exchange of water with the Paratethys declined. In the Messinian (6.3 Ma), connections between some marginal Mediterranean basins, for example, the proto‐Adriatic basin, and the Central Mediterranean, became restricted. In this basin, the Sr isotope values fell below the global reference line, while Nd isotope ratios show a strong affinity with the Atlantic Ocean and also indicate freshwater input. We conclude that the Mediterranean Nd isotope signature differs from that in the open oceans and reflects the basin physiography, reflecting a mix of signals derived from the adjacent oceans and local signals.

At the crossroads: early Miocene marine fishes of the proto-Mediterranean Sea

“…The Felli section, which is our study section, includes only the uppermost part of the Pentalofos Formation corresponding to the Aquitanian according to Mavridis et al (1985). The Pentalofos Formation overlies the Eptachori Formation and is overlain, conformably in the Grevena area, by the Tsotyli Formation (Fermeli and Ioakim, 1992).…”

“…Connectivity between marine realms largely controls the fate of fish populations and biodiversity (Worm and Tittensor, 2018). Early Miocene proto-Mediterranean biodiversity is particularly interesting because, at that time, the basin's connection with the Indo-Pacific realm ceased to exist (Rögl, 1998;Bialik et al, 2019;Torfstein and Steinberg, 2020;Sun et al, 2021), while the marine biodiversity hotspot was shifting toward the southeast (Renema et al, 2008) and the climate was cooling (Cornacchia et al, 2018), marking the onset of a subtropical gradually oligotrophic regime in the proto-Mediterranean Sea. However, the early Miocene fossil fish record from the Mediterranean area is particularly sparse.…”

Chamberlainium pentagonum (Conti) comb. nov. and Spongites fruticulosus (Corallinales, Rhodophyta) in the Miocene carbonates of the western Mediterranean

“…Presently, Chamberlainium is reported to occur along the coasts of the Indo-Pacific Ocean (South Africa, Taiwan and California, while it is absent from the Mediterranean . However, the presence of an Indo-Pacific species in the Mediterranean during the Miocene is not surprising since the two oceans were strongly connected during the early Miocene and limited connections existed also during the middle Miocene (CORNACCHIA et al, 2018, and references therein).…”

Paleocene to Miocene southern Tethyan carbonate factories of the Southwestern and Western Central Asia

“…The collision between the Arabian and Eurasian plates probability initiated during the latest Eocene -early Oligocene and was entirely completed before ca. 14 Ma (middle Miocene) (Ballato et al, 2010;Agard et al, 2011;Cornacchia et al, 2018;Bialik et al, 2019;GholamiZadeh et al, 2021), leading to the end of marine sedimentation in most of the Mesopotamian and Iranian regions (i.e., the central part of the study area) during the Miocene (Ziegler, 2001;Al-Juboury and McCann, 2008;Mossadegh et al, 2009;Reuter et al, 2009;Mohammadi et al, 2013;Sissakian, 2013;Ameen-Lawa and Ghafur, 2015;Sadooni and Alsharhan, 2019) (Fig. 1).…”