This dataset contains stable and clumped isotope data obtained from pedogenic carbonates sampled across a continental sedimentary section at Büyükteflek (Anatolia, Turkey). The section spans the Priabonian and lower Rupelian stages (~37–33 Ma), including the Eocene–Oligocene Transition (EOT) and the Early Oligocene Glacial Maximum (~33.65 Ma). Clumped isotope analyses (Δ47) were performed on pedogenic carbonate to reconstruct paleotemperatures, while stable isotope measurements (δ¹³C and δ¹⁸O) were used to document paleoenvironmental and hydrological changes across the record.

Clumped isotopes results contains clumped isotope measurements (Δ47) and derived paleotemperature estimates from the same samples, analysed at CEREGE (Aix-en-Provence, France).Stable isotope analyses (δ¹³C, δ¹⁸O) were performed on 23 calcite-dominated pedogenic carbonate powders using a Thermo 253+ mass spectrometer coupled to a Thermo Kiel IV device (Dual Inlet mode) at CEREGE (Aix-Marseille University). Sample powders (80–120 µg) reacted with 105% phosphoric acid at 70°C. Values are reported relative to IAEA-603 in the V-PDB reference frame. 14 samples were selected for clumped isotope analysis (Δ47). Samples were pre-treated with 3–8% NaOCl to remove organic contamination, then analysed on the same system with an additional Porapaq cryotrap at -20°C. Δ47 values are projected onto the I-CDES90 scale using D47crunch (Daëron, 2021), pooling data from 28 sessions (inter-session repeatability: 30 ppm). Paleotemperatures are calculated using the Anderson et al. (2021) calibration. Full analytical details are provided in Supplementary Text S1 of Botté et al. (preprint).