Climate variability in the Salawusu River valley of the Ordos Plateau (Inner Mongolia, China) during Marine Isotope Stage 3

Abstract

Fluctuations in climatic proxies of the Milanggouwan section in the Salawusu River valley of the Ordos Plateau (Inner Mongolia, China) during Marine Isotope stage 3 (MIS 3) coincide well with sedimentary cycles for palaeo-mobile dune sands alternating with fluvial - lacustrine facies and palaeosols. We compared the palaeo-mobile dune sands with modern mobile dune sands (products of a cold and dry climate dominated by the East Asian winter monsoon), whereas the fluvial-lacustrine facies and palaeosols were controlled by a wet - warm climate similar to that of the East Asian summer monsoon. The MIS 3 climate of the Salawusu River valley appears to have experienced at least nine wet-warm and ten cold-dry fluctuations, divided into five stages: MIS 3e (58 900-49500 yr BP), MIS 3d (49 500-40 700 yr BP), MIS 3c (40 700-36 900 yr BP), MIS 3b (36 900-27 000 yr BP) and MIS 3a (27 000-22 300 yr BP). The 19 cold-warm climatic fluctuations corresponded roughly to the GRIP and Guliyan records, and with fluctuations in the North Atlantic climate. Notable peaks in the spectral analysis occurred at 19 500 yr, 1020 yr, 640 yr and 500 yr. Our results show that the millennial-centennial climate was closely related to the relative strengths of East Asian monsoons, which are controlled by the North Atlantic thermohaline circulation, and which is also closely linked to the Sun's precession period. Copyright © 2008 John Wiley & Sons, Ltd.