关键词: Sr-Nd同位素, 物源示踪, 气候变化, 长江, 黄河

Abstract: The provenance study of the major loess deposits in eastern China can help understand the evolution since the late
Quaternary in this area. Nd and Sr isotopes are the most commonly used source tracers for atmospheric dusts. This work applies the
Sr-Nd isotope to trace the source of classical loess deposits in eastern China, including the Shandong Peninsula and its adjacent
coastal area, the loess deposits along the lower reaches of the Yellow River and the Xiashu loess deposits in the lower reaches of the
Changjiang. We found that the Sr-Nd isotope composition was different between the loess in eastern China and the loess on the
Chinese Loess Plateau, suggesting a different source region for the loess in eastern China. The Sr-Nd isotope data indicate that the
loess deposits in eastern China mainly came from the near source. The loess deposits in the Shandong Peninsula and its adjacent
coastal area show similar εNd values and 87Sr/86Sr ratios ranging from 0.7140 to 0.7155, which were blown from the Yellow River
sediments exposed on the floodplain and the shelf during glacial times. The loess in the lower reaches of the Yellow River show similar
Sr-Nd isotope values with the sediments in the floodplain of lower reaches of Yellow River, suggesting that the floodplain of lower
reaches of Yellow River was the major source for the loess in the lower reaches of the Yellow River. The Xiashu loess deposits show 87Sr/ 86Sr ratios ranging from 0.7194 to 0.7209, which is lower than that of modern sediments in the lower reaches of the Changjiang, and εNd
values ranging from -11.3 to -12.0. The source region of fine grains in Xiashu loess has not yet been determined and needs further
study. The formation of loess deposits in eastern China may be related to the desertification during the glacial climate since the middle
Pleistocene transition.

Key words: Sr-Nd isotope, source tracing, climate change, Changjiang, Yellow River