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Sr isotope records from marginal marine basins track the mixing between seawater and local continental runoff, potentially recording the effects of sea level, tectonic, and climate forcing in marine fossils and sediments. Our 110 new Sr-87/Sr-86 analyses on oyster and foraminifera samples from six late Miocene stratigraphic sections in southern Turkey, Crete, and Sicily show that Sr-87/Sr-86 fell below global seawater values in the basins several million years before the Messinian Salinity Crisis, coinciding with tectonic uplift and basin shallowing. 87Sr/86Sr from more centrally located basins (away from the Mediterranean coast) drop below global seawater values only during the Messinian Salinity Crisis. In addition to this general trend, 55 new Sr-87/Sr-86 analyses from the astronomically tuned Lower Evaporites in the central Apennines (Italy) allow us to explore the effect of glacio-eustatic sea level and precipitation changes on Sr-87/Sr-86. Most variation in our data can be explained by changes in sea level, with greatest negative excursions from global seawater values occurring during relative sea level lowstands, which generally coincided with arid conditions in the Mediterranean realm. We suggest that this greater sensitivity to lowered sea level compared with higher runoff could relate to the inverse relationship between Sr concentration and river discharge. Variations in the residence time of groundwater within the karst terrain of the circum-Mediterranean region during arid and wet phases may help to explain the single (robust) occurrence of a negative excursion during a sea level highstand, but this explanation remains speculative without more detailed paleoclimatic data for the region.

[1] The southwest margin of the Central Anatolian Plateau has experienced multiple phases of topographic growth, including the formation of localized highs prior to the Late Miocene that were later affected by wholesale uplift of the plateau margin. Our new biostratigraphic data limit the age of uplifted marine sediments at the southwest plateau margin at 1.5 km elevation to

[1] A high-resolution quantitative analysis of the calcareous planktonic assemblages (planktonic foraminifers and calcareous nannofossils) at the Punta Piccola section (at the base of which, the global standard stratotype-section and point of the Piacenzian stage is defined) provided a more accurate biostratigraphy for the Mediterranean middle Pliocene (2.6–3.6 Ma). In particular, an astronomically calibrated age of 2.87 Ma was estimated for the Pliocene first occurrence of Neogloboquadrina atlantica instead of the younger previously proposed age of 2.72 Ma. Spectral analysis performed on the Globigerinoides species (spp.) planktonic foraminifera assemblage along with cross-spectral analysis between the same record and the astronomic target curve La(041,1) calculated for the summer season (June–July) at 65°N provided solid evidence that the Globigerinoides spp. group of planktonic species is a reliable recorder of orbital forcing and can be appropriately used for astronomical tuning of marine sedimentary records. The same procedures of spectral analysis were applied to the individual species that constitute the Globigerinoides spp. group (G. ruber, G. obliquus, and G. quadrilobatus), thus resolving their different frequency structures and species-specific response to the different astronomic periodicities. Whereas G. obliquus and G. quadrilobatus appear primarily controlled by precession, G. ruber is largely forced by obliquity. Small ecological differences, mainly related to dissimilar food quality requirements, were assumed to distinctively control the time distribution of the two groups of species. Precessionally forced oligotrophic conditions in the surface Mediterranean waters, induced by summer continental runoff, led to a dominance of copepods-based dietary, typical of G. quadrilobatus. Conversely, obliquity cycles drove the abundance distribution of G. ruber in the sea surface waters of the Mediterranean, influencing the sea surface temperature, light intensity, and/or phytoplankton distribution. Sub-Milankovitch periodicities (cycles ∼1500, 2500, 3000, and 4500 years long) are reliably detected in the faunal records, suggesting that millennial-scale variability punctuated the Mediterranean climate regime during the interval of the middle Pliocene Northern Hemisphere glaciation.