Fig. 3.

δ¹⁸O fluctuations linked to eccentricity and obliquity orbital variations at 4.5–7.1 Ma. Lacustrine phases (high δ¹⁸O) generally correspond to periods of high eccentricity and obliquity. Fluvial-eolian environment (low δ¹⁸O, highlighted with gray bars), developed more around 6.5, 6.1, 5.7, and 5.2 Ma, at a ∼400-ky eccentricity beat. The red bar indicates the last occurrence of lacustrine environment at ∼4.9 Ma. Occurrences of ostracod assemblages with total number >100 are also indicated.