Foraminiferal Nd isotope evidence for Burdigalian–Langhian water mass reorganization in the Adana and Adıyaman basins, Eastern Mediterranean (Türkiye)

Abstract

The Middle Miocene represents a crucial interval to reconstruct the paleoceanographic evolution of the Eastern Mediterranean, marked by different events such as the closure of the seaways, or intense tectonic and volcanic activity. In this study, we present new foraminiferal Sr–Nd isotopic and elemental ratio data from four Burdigalian–Langhian sections in south-eastern Türkiye (Adana and Adıyaman basins). Elevated Fe/Ca, Al/Ca, Mn/Ca and Mg/Ca ratios indicate substantial non-carbonate admixture, with an additional Mg contribution that cannot be attributed to aluminosilicate detritus alone. The systematic offset between foraminiferal and detrital ε_Nd nevertheless indicates that primary water mass signals are partially preserved. The ε_Nd foraminiferal data reveal section-dependent paleoceanographic conditions. The Adıyaman Basin record is dominated by anomalously radiogenic values expressing important admixture of volcanic material and therefore carries limited value as a water mass tracer. Within the Adana Basin, the late Burdigalian record suggests opening of Eastern Mediterranean connectivity, while Langhian sections record spatial heterogeneity between sub-basins, indicating both Paratethyan and Mediterranean influences. This pattern may reflect the position of the Adana Basin as an inner foredeep position inboard of the Cyprus Arc, distinct from open Mediterranean waters. These results highlight how tectonics, volcanism, and global climatic forcing are linked to marine connectivity in the Eastern Mediterranean during the Middle Miocene.