High-resolution scanning XRF investigation of Chinese loess and its implications for millennial-scale monsoon variability

• Published in: Journal of Quaternary Science
• Main Authors: Sun, Youbin, Liang, Lianji, Bloemendal, Jan, Li, Ying, Wu, Feng, Yao, Zhengquan, Liu, Yanguang
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2016
• Subjects: Chinese Loess; East Asian Monsoon; Elemental Ratios; Millennial Variability; Monsoon Dynamics; Science & Technology; Physical Sciences; EAST-ASIAN MONSOON; PAST 800,000 YEARS; NORTH-ATLANTIC; CLIMATE VARIABILITY; SUMMER MONSOON; GRAIN-SIZE; ICE-VOLUME; MAGNETIC-SUSCEPTIBILITY; ANTARCTIC CLIMATE; LAST GLACIATION; Physical Geography; Geology; Geography; Physical; Geosciences; Multidisciplinary; Antarctic; Greenland; Antarc*; North Atlantic
• Online Access: http://ir.ieecas.cn/handle/361006/5725; https://doi.org/10.1002/jqs.2856

Millennial-scale monsoon variability has been investigated intensively using loess-based proxies; however, the amplitude and rhythms of millennial-scale signals have seldom been disentangled from the background glacial-interglacial changes. Here we present the results of high-resolution scanning X-ray fluorescence analysis of a 75-m-thick loess sequence from the north-western Chinese Loess Plateau to address glacial-interglacial to millennial monsoon variability over the last two climatic cycles. Variations of the Si/K, Fe/K and Ca/K ratios are separated spectrally into low-and high-frequency components corresponding to glacial-interglacial and millennial-scale monsoon variability, respectively. The results indicate that the three elemental ratios exhibit similar glacial-interglacial variability but with varying spectral densities at the 100-, 41- and 23-kyr periodicities. Millennial-scale variability is quite similar between the three elemental ratios, and comparable to those inferred from records of Chinese speleothem delta O-18, Greenland palaeotemperature and North Atlantic cooling events. Comparison of various proxies indicates the broad similar magnitudes of abrupt climate changes, at least during the last two glacial-interglacial cycles, whereas the timing and amplitude of abrupt climatic events are not well correlated. We suggest that refinement of loess chronology and intensive data-model integration in the future are critical to decipher the characteristics and dynamics of rapid monsoon changes. Copyright (c) 2016 John Wiley & Sons, Ltd.