Loesspaleosol sequences have been applied to retrieve palaeoenvironment change in the study of the paleoclimatic evolution. Chafangcun (CFC) at Shangdan basin

Shaanxi provides such a loesspaleosol profile. At this profile

loess sequence's color and structure were investigated

and 210 samples were systematically collected for grain-size analysis. The results showed that: ① Chafangcun loess-paleosol sequence in the first river terrace with typical atmospheric dust sediment along the Danjiang River

has formed since 55 000 a BP. ② This loess sequence is mainly composed of silt (5~50 μm) and clay (<5 μm)

with an average proportion of 86.65%. The coarse silt of 10~50 μm in size is dominant composition in CFC profile

accounting for 46.81% on average

and clay (<5 μm in size) accounts for 23.94% in total composition. The sequence's grain-size composition varies from bottom to top stratigraphic unit

and the paleosol is smaller in grain size than that of their loess stratum. These properties reflect that the weathering intensity in paleosol is stronger than in loess. ③ The grain-size characteristics in the Shangdan Basin reveal that the palaeo-climate changed successively in the following four stages: a cold and dry climate during the last glacial (55 000~11 500 a BP)

a climate from dry & cold to warm & humid during the early Holocene (11 500~8 500 a BP)

a warm and humid climate during the middle Holocene (8 500~3 100 a BP)

and the lower temperature and reduced precipitation climate during the late Holocene (3 100~0 a BP).