| A regional study of loess-palaeosol stratigraphy and sedimentology, during the last interglacial-glacial cycle, has used three different scales of observation to develop a new, conceptual model of loess deposition in the Chinese Loess Plateau. The model is based on spatial and temporal variations in loess grain size, accumulation rates and thickness, and indicates that variations in loess characteristics are part of an evolving desert-loess depositional system. In this system, the desert is the main source of loess and influences loess distribution via desert expansion and contraction during glacial and interglacial periods, respectively. Desert expansion and contraction was forced, in part, by changes in soil moisture that is influenced by extent of the Fennoscandian ice-sheet and the atmospheric circulation pattern that it induces downstream.; Within the last glacial unit (∼12–74 ky), lateral changes in stratigraphy from desert sand to loess (proximal to the source), or loess to soil (distal from the source) are driven by variations in the balance between loess accumulation rates and pedogenesis. In addition, vertical alternations of loess and palaeosols are driven by changes in accumulation rates along a shifting climatic gradient. At a higher resolution, correlations suggest that millenial-scale variations in grain size propagate through the central Loess Plateau. The geometry of the high resolution correlations is similar to the geometry of the Malan formation and its members, suggesting that the Malan loess is stratified, and that there was a relatively consistent wind direction during deposition of the Malan.; These results suggests that there are global effects (changes in ice volume), regional effects (i.e. changes in Eurasian ice sheets), and local effects (i.e. changes in the position of the desert margin) that have an influence on loess-palaeosol stratigraphy and loess deposition in China. However, not all variations in loess-palaeosol stratigraphy or sedimentology are related to climate change. Some high frequency variations may result from non-climatic effects, rather than global or hemispherical climatic change. |
