Quaternary Science Reviews 21 (2002) 811–817 Regional lithofacies and pedofacies variations along a north to south climatic gradient during the Last Glacial period in the central Loess Plateau, China C.D. Rokosh a, *, N.W. Rutter a , Z. Ding b , J. Sun b a Department of Earth and Atmospheric Sciences, University of Alberta, Edmonton, AB, Canada T6J 2E3 b Academy of Sciences, Beijing, China Received 2 October 1999; accepted 3 August 2000 Abstract Five lateral sand–loess–palaeosol continua occur within the last glacial sediments of the central Loess Plateau of China along a 500km north to south climatic gradient. The continua shift southward or northward in concert with desert expansion or contraction, respectively. Lateral lithofacies (desert sand to loess) variations are evident at the north end of the gradient and follow Walther’s Law of the correlation of facies. Lateral pedofacies (loess to palaeosol) variations are present near the south end of the gradient,wheretheclimatewaswarmerandwetter.Thelateralstratigraphicchangesfromsandtoloessorloesstosoilaredrivenby variations in the rate of sedimentation along a climatic gradient. Vertical stratigraphic profiles at the north end of the gradient reveal alternating sand and loess beds. In contrast, alternating loess and palaeosols occur within the same stratigraphic interval in the southern Loess Plateau, where dust accretion rates were lower. However, in high resolution studies of climate change vertical profiles of alternating loess and palaeosols (especially weak palaeosols) may not reflect regional or global climate change. Alternating loess and weak palaeosols may reflect local variations in the balance between the rates of dust accretion and pedogenesis. Local fluctuations in either of these rates could result in the presence of time equivalent loess and palaeosols at high resolutions. Thus, some of the high resolution loess-palaeosol alternations may reflect local climatic variation rather than global or hemispherical climate change. r 2002 Published by Elsevier Science Ltd. 1. Introduction Quaternary stratigraphy of the Loess Plateau, China (Fig. 1) has largely been based on palaeosol counting (Liu, 1985), because of the lateral persistence of alternating loess and palaeosols (Pavlinov, 1959; Liu, 1985). The alternation of loess beds and palaeosols in China is, in part, a function of a relative balance between the rate of pedogenesis and the rate of loess deposition (An et al., 1991; Zheng et al., 1994). Loess and palaeosols are interpreted as coinciding with marine palaeoclimate stages. Liu (1985), Kukla (1987a,b), and Liu et al. (1995) demonstrated a chronostratigraphic correlation of marine oxygen isotope stages (OIS) 2, 3 and 4 (last glacial) with the Malan loess (L1), and OIS 5 (last interglacial) with palaeosol S1 (Fig. 2). In the southern Loess Plateau, high resolution (e.g. 10cm sample interval or less in this study) correlations of loess and palaeosols with regional palaeoclimate boundaries are complicated by a low dust accretion rate and a relatively high mean annual temperature and precipita- tion. These factors result in palaeosol welding such as in palaeosol S1 (Guo and Fedoroff, 1991). In the northern Loess Plateau, near the desert margin, loess accumula- tion rates are higher than in the south, while mean annual temperature and precipitation are lower. The result is a clear stratigraphic alternation of loess beds and palaeosols, such as in palaeosol S1 at Yulin (Fig. 2), where soils developed during periods of reduced dust input and more favorable climate (Pye, 1987; Pye and Tsoar, 1987; An et al., 1991). According to Pye (1987), changes in the dust accretion rate or the rate of rainfall through time, along a theoretical transect, will cause a shiftinthepointwheretherateofweatheringequalsthe rate of dust accretion, and produce a stratigraphic sequence of alternating weathered loess (or soil) and relatively unweathered loess (Pye, 1987; Pye and Tsoar, 1987). Hence, in the Loess Plateau there is a change in *Corresponding author. Tel.: +1-780-492-1120; fax: 1-780-492- 2030. E-mail address: drokosh@ualberta.ca (C.D. Rokosh). 0277-3791/02/$-see front matter r 2002 Published by Elsevier Science Ltd. PII:S0277-3791(01)00129-9