State Key Laboratory of Cryospheric Science, 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 Pollut Res Int. 2021 Sep;28(33):45765-45779. doi: 10.1007/s11356-021-13561-x. Epub 2021 Apr 20.
To provide insight into dust sources in snow deposited during the non-monsoon period on the Tibetan Plateau, detailed post-Archean Australian shale (PAAS)-normalized rare earth element (REE) distribution patterns and variations in REE tracers, such as La/Yb, La/Er, and Gd/Yb with depth, as well as the distribution of samples in the plots of REE ratio pairs, such as La/Yb vs. Y/ΣREE, La/Er vs. Gd/Er, and Y/La vs. Nd/Er, were compared in seven potential dust source areas in Asia. Snow samples from five glaciers, i.e., Qiumianleike (QMLK), Meikuang (MK), Yuzhufeng (YZF), Xiaodongkemadi (XDKMD), and Gurenhekou (GRHK), were collected from April 26 to May 13 before the onset of monsoon activity. The results show that dust trapped in snow pits from the studied glaciers, i.e., QMLK, MK, XDKMD, and GRHK, has varying degrees of contribution from the Taklimakan Desert, Qaidam Basin, and the surface soil of the Tibetan Plateau. There are signals of the Tengger and Badain Jaran Desert and Chinese Loess in the MK and XDKMD snow pit samples or in the QMLK and GRHK surface samples from the REE tracers; however, from the point of view of the land location, the three dust sources should not be the major contributors. Signals of dust from the Indian Thar Desert were occasionally detected from the MK, YZF, and XDKMD snow pit samples and GRHK surface snow samples, implying the intrusion of early Indian monsoon activities to the sites. The dust signal from the Thar Desert in India from the YZF glacier is significantly greater than that from the XDKMD and MK glaciers. These findings were also supported by the tracer of dust transmitted to the three snow pits through the air mass backward trajectories. The new finding of this study is that dust from the Indian Desert can even reach the Kunlun Mountains in the northern region of the Tibetan Plateau. The conclusions are helpful in interpreting the sources of dust and the pollutants absorbed by dust particles, as well as the extent of the impact of Indian monsoon activities at the end of the non-monsoon season on the plateau.
为了深入了解青藏高原非季风期积雪的尘埃来源，我们详细比较了亚洲七个潜在尘埃源区后太古澳大利亚页岩（PAAS）归一化稀土元素（REE）分布模式和 REE 示踪剂（如 La/Yb、La/Er 和 Gd/Yb）随深度的变化，以及 REE 比值对（如 La/Yb 对 Y/ΣREE、La/Er 对 Gd/Er 和 Y/La 对 Nd/Er）在样本中的分布情况。我们在五个冰川（分别是乔美来克冰川（QMLK）、美棵岗冰川（MK）、玉珠峰冰川（YZF）、小冬克马迪冰川（XDKMD）和古里雅冰川（GRHK））采集了雪样，采集时间是季风活动开始前的 4 月 26 日至 5 月 13 日。结果表明，从所研究的冰川（QMLK、MK、XDKMD 和 GRHK）采集的雪坑尘埃在不同程度上受到了塔克拉玛干沙漠、柴达木盆地和青藏高原表面土壤的影响。MK 和 XDKMD 雪坑样本或 QMLK 和 GRHK 表面样本中的 REE 示踪剂显示出腾格里沙漠和巴丹吉林沙漠以及中国黄土的信号，但从地理位置来看，这三个尘埃源不应是主要贡献者。MK、YZF 和 XDKMD 雪坑样本以及 GRHK 表面雪样本中偶尔会检测到来自印度塔尔沙漠的尘埃信号，表明早期印度季风活动已经到达了这些地点。来自印度 YZF 冰川的塔尔沙漠尘埃信号明显大于来自 XDKMD 和 MK 冰川的信号。这些发现也得到了通过大气质量后向轨迹传输到三个雪坑的尘埃示踪剂的支持。本研究的新发现是，印度沙漠的尘埃甚至可以到达青藏高原北部的昆仑山脉。这些结论有助于解释尘埃来源和尘埃颗粒吸附的污染物，以及季风活动末期对高原的影响程度。
