Biomarker and pollen in core SG-1 from Tibetan Plateau spanning the Mid-Pleistocene Transition

Paleohydrological data comprising pollen assemblages and leaf-wax hydrogen isotopes (δDwax) from paleolake sediments in the Qaidam Basin (China) provide evidence for a link between increased moisture availability on the Tibetan Plateau and global cooling during the Mid-Pleistocene Transition. Notably, they document the persistence of humid and cold conditions during Marine Isotope Stages 24–22 (936–866 ka) suggesting that boundary conditions favorable for extended glaciation on the Tibetan Plateau first developed at ~900 ka. Our δDwax results indicate a strong influence of proximal (monsoonal) moisture sources during that glacial, in agreement with the intensification of the inter-hemispheric moisture transport resulting from Antarctic ice-volume increase at ~900 ka. The consistency of our results with other marine and terrestrial climate datasets suggests that extended glaciation on the Tibetan Plateau may have initiated ~500 ka earlier than previously assumed, implying that mid-latitude ice sheets actively contributed to global cooling during the Mid-Pleistocene Transition.