Recent developments in research on the loess in China

Loess is well developed at the middle latitude of the Eurasian continent. I occupies nearly 400,000 km2 in North China, mainly in the middle reaches of the Yellow River forming the famous loess plateau. The loess plateau is situated also longitudinally at the zone where the monsoon from the east meets the drier west wind. The distributional characteristics of the loess with other sediments are generally developed in parallel belts from the NW to the SE, as the Gobi desert, the desert, and the loess. Loess itself shows also a gradational distribution.Recent studies have shown that loess has a higher depositional rate in the west of the loess plateau than in the east. A 240 m thick loess sequence in Lanzhou has been deposited since the Olduvai subchron (1.8 m.y.) while to the east in Luochuan, the similar sequence has a thickness less than 135 m.Loess deposition in China has a long time span as well as a large spatial distribution. Recent studies in Baoji about 200 km west of Xian in the Weihe River Valley in the southern part of the loess plateau have indicated that it has a time span no less than 2.5 million years.The profile in Baoji shows that there are better developed loess-palaeosol sequences than other loess profiles. It has altogether 37 cyclic climatic pairs. The cyclic nature of these deposits in such a long time span is useful for the understanding of global climatic changes