State Key Laboratory of Cryosphere Sciences, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China.
University of Chinese Academy of Sciences, Beijing 100049, China.
Environ Sci Technol. 2021 Jul 20;55(14):10121-10132. doi: 10.1021/acs.est.0c04929. Epub 2021 Jul 6.
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, Sr/Sr ratios gradually increased, while ε and ε values gradually decreased; from west to east, Sr/Sr and ε gradually increased, while ε 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.
青藏高原（TP）的大片干旱地区正在发生沙漠化，并随后发生风沙排放和传输。TP 土壤对亚洲和其他地区大气气溶胶负荷的贡献尚不清楚。在这里，我们使用 Hf、Nd 和 Sr 同位素来区分 TP 与其他亚洲产尘区，并将特征与主要尘埃汇区的沉积物进行比较。我们发现，TP 土壤的 Hf-Nd-Sr 同位素具有独特的空间特征。从北到南，Sr/Sr 比值逐渐增加，而 ε 和 ε 值逐渐降低；从西到东，Sr/Sr 和 ε 逐渐增加，而 ε 变化不明显。TP 土壤的 Hf-Nd-Sr 同位素组成受四个地理同位素区控制：北、南、西、东 TP。与亚洲大型沙漠相比，TP 显示出独特的同位素组成，共同在整个亚洲呈现出显著的空间变化。与显著汇区的尘埃同位素相比，我们发现 TP 是东亚 TP 冰川、中国黄土高原、南海、日本和格陵兰岛的重要尘埃源。这项研究提供了明确的同位素证据，表明 TP 是北半球主要的风沙贡献者，可能对全球风沙循环具有重要意义。
