δ¹³C and δ¹⁸O measurements on dental enamel of mammalian fauna from Early Pleistocene (~1.2 Ma) hyena den at the Haro River Quarry, Pakistan

This dataset contains stable carbon (δ¹³C) and oxygen (δ¹⁸O) isotope measurements of mammalian dental enamel from the Haro River Quarry (HRQ), an Early Pleistocene (~1.2 Ma) hyena den in the Campbellpore Basin, Pakistan. The Haro River Quarry is the only known in-situ Pleistocene bone bed in the Himalayan Foreland Basin and has been identified as a cub-provisioning den of the giant extinct hyena Pachycrocuta brevirostris. The short-duration accumulation makes this assemblage an exceptional paleoecological snapshot of the Campbellpore Basin at ~1.2 Ma. A total of 103 stable isotope measurements were obtained from 71 specimens spanning six mammalian families: Cervidae, Bovidae, Suidae, Hyaenidae, Mustelidae, and Hystricidae. All samples were analyzed at the University of Arizona, using a Kiel IV carbonate preparation device coupled to a Thermo MAT253+. Values are reported in per mil (‰) relative to Vienna Pee Dee Belemnite (VPDB). External analytical precision was ±0.05‰ for δ¹³C and ±0.07‰ for δ¹⁸O. The isotopic data reveal a landscape structurally dominated by C4 grasslands, with persistent C3 and mixed C3–C4 microhabitats. These results provide the first direct evidence of vegetation heterogeneity in the western Siwaliks (Pakistan) during the Early Pleistocene and complement existing pedogenic carbonate records, which alone suggest environmental homogeneity in the region.