Hf-Nd-Sr Isotopic Composition of the Tibetan Plateau Dust as a Fingerprint for Regional to Hemispherical Transport

Large areas of arid regions in the Tibetan Plateau (TP) are undergoing desertification and subsequent aeolian emission and transport. The contribution of TP soils to the atmospheric aerosol burden in Asia and elsewhere is not known. Here, we use Hf, Nd, and Sr isotopes to distinguish the TP from other Asian dust-producing regions and compare the signatures to sediments in major dust sink regions. We found that the Hf-Nd-Sr isotopes of TP soils showed unique spatial signatures. From north to south, 87Sr/86Sr ratios gradually increased, while eNd and eHf values gradually decreased; from west to east, 87Sr/86Sr and eHf gradually increased, while eNd changed indistinctly. The Hf-Nd-Sr isotopic compositions of TP soils were controlled by four geographic isotope regions: the northern, southern, western, and eastern TP. Compared with Asian large deserts, the TP showed a unique isotopic composition, which together exhibited a significant spatial change across Asia. Compared to dust isotopes in prominent sink areas, we found that the TP is an important dust source to eastern TP glaciers, the Chinese Loess Plateau, South China Sea, Japan, and Greenland. This study provides clear isotopic evidence that the TP is a major aeolian contributor in the Northern Hemisphere and may have important implications for the global aeolian cycle.