《Beijing region》.pdfVIP

JOURNAL OF QUATERNARY SCIENCE (2001) 16(6) 575–582 Copyright  2001 John Wiley Sons, Ltd. DOI: 10.1002/jqs.618 Climatic implications of loess deposits from the Beijing region ∗ SHANGFA XIONG , ZHONGLI DING and TUNGSHENG LIU Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China Xiong, S., Ding, Z. and Liu, T. 2001. Climatic implications of loess deposits from the Beijing region. J. Quaternary Sci., Vol. 16 pp. 575–582. ISSN 0267-8179. Received 10 August 2000; Revised 10 January 2001; Accepted 19 January 2001 ABSTRACT: Variations in magnetostratigraphy, pedostratigraphy, grain size and magnetic suscep- tibility of the loess deposits near Beijing have been studied at two sections. The sections are about 400 km east of the main loess deposits in China, have a maximum thickness of 100 m and extend back to 1.1 Ma. The sequence consists of 14 loess–palaeosol couplets (S0-S14), which correlate well with sequences in the Loess Plateau. Susceptibility records from the sites near Beijing are comparable to the Xifeng, Luochuan and Baoji sections located in the middle part of the Loess Plateau; however, the down-core variations in the grain size in the Upper Lishi Formation exhibit some differences. Journal of Quaternary Science The median grain size increases by about 25–30 µm from L4 to L2, with the sandy grains (63 µm) increasing from 10–20 wt% to 40–50 wt% . This implies that the depositional environment of the dust sources in the Beijing loess section is different in some aspects from the Loess Plateau. The Beijing loess may have had a different dust source than the Loess Plateau. Copyright  2001 John Wiley Sons, Ltd. KEYWORDS: loess; Beijing; susceptibility; grain size; desert. Introduction Previous studies have shown that loess deposits are widely