NOAA/WDS Paleoclimatology - Northeast African Precipitation and Vegetation Biomarker Data over the last 4.5 million years

The eastern Mediterranean sapropels, paced by insolation, provide a unique archive of African monsoon strength over the Late Neogene. However, the longer-term climate of this region lacks characterization within the context of changes in ice volume, sea surface temperature gradients, and terrestrial ecosystems. Here, we examine C28 n-alkanoic acid leaf wax hydrogen and carbon isotopes in sapropels, sourced from northeast Africa, along with vegetation-corrected precipitation isotopes, derived from astronomically dated sediment cores from ODP 160 Sites 966 and 967 since 4.5 million years ago. Despite sampling only wet-phase sapropels for African monsoon variability, we find a larger range in hydrogen isotopes than previously published data across wet-dry precession cycles, indicating the importance of long-term modulation of Green Sahara phases throughout the Neogene. An influence of orbital properties on regional monsoonal hydroclimate is observed, controlling up to 50% of total hydrogen isotope variance, but large changes outside of these typical frequencies account for at least 50% of the total variance. This secular trend may track changes in ice volume, tropical sea surface temperature, sea surface temperature gradients, or even lower-frequency orbital cycles. Long-term hydroclimate and environmental shifts provide new contexts for milestone events in northeast African hominin dispersal and evolution. Leaf wax hydrogen and carbon isotope records from an Eastern Mediterranean sediment core to demonstrate precipitation and vegetation of northeast African over the last 4.5 million years. Coordinates for S1: 966A: 33.7966, 32.7016 966B: 33.7961, 32.7015 966C: 33.7963, 32.7015 966D: 33.7965, 32.7008 967A: 34.0683, 32.7254 967B: 34.0682, 32.7254 967C: 34.0712, 32.7255 967D: 34.0709, 32.7255 Provided Keywords: Paleoclimate, Northeast Africa, Organic geochemistry, Biomarkers, Precipitation, Human Evolution