THE LAST GLACIAL STRATIGRAPHIC SEQUENCE, DEPOSITIONAL ENVIRONMENT ANDCLIMATIC FLUCTUATIONS FROM THE AEOLIAN SAND DUNE IN HONGGUANG, PENGZE, JIANGXI (CHINA)

The Hongguang sand hill is located along the south bank of the Yangtze River in Pengze County, Jiangxi Province, China, rising more than 50 m above the ground. It consists of aeolian sand beds interbedded with 11 relatively thin palaeosols. The aeolian sand beds include dune-depo sited cross-stratified sand beds and interdune-deposited horizontally- stratified sand beds, both being well sorted. The 11 palaeosols are nu mbered as Z(1) to Z(11) from bottom to top in chronological order. Amo ng them, 10 palaeosols (Z(2) to Z(11)) are dark brown soils while Z(1) includes black to very dark grey lenses of peaty soil, which change l aterally into dark brown soil. A hierarchy of bounding surfaces, as su mmarized by Kocurek (1988), can be recognized in the sand hill includi ng super surfaces (namely palaeosols), first- and third-order bounding surfaces. The formation of palaeosols represents hiatuses between aeo lian sand depositions and suggests a climatic change from arid to more humid conditions. C-14 dates show that the sequence from Z(1) to Z(7) was formed between about 26,000 and 20,000 BP, indicating that each c ycle from the aeolian sands to palaeosol, that is, each arid-to-humid climatic shift, spent an average term of about 1000 a. Analysis of sed imentary features of the sand hill shows that the aeolian sand grains were mainly from the Palaeo-Yangtze River, which was probably an inter mittent river during the dune development. Discussion is also made on the possible palaeoclimatic linkage between the Hongguang area and the North Atlantic region during the last glaciation. (C) 1997 Elsevier S cience Ltd.