Chinese loess is regarded as one of the most detailed and long-term archives of climate on land. However, there is still signifi cant controversy over the deposit's origin, limiting interpretation of the sedimentological and paleoclimatic mechanisms responsible for its emplacement. Here this is addressed through morphology and the fi rst laser ablationinductively coupled plasma-mass spectrometer (LA-ICP-MS) U-Pb ages of detrital zircons from loess (last glacial age; northern Loess Plateau). These are compared to zircon U-Pb age spectra from desert and sandy lands surrounding the Loess Plateau. Surface samples were taken from the Tengger and Mu Us deserts, as well as the Horqin and Otindag sandy lands. The results demonstrate that zircon U-Pb ages can discriminate between potential source areas and highlight both similarities and differences in age spectra for the desert and sandy land samples. Most signifi cantly, the loess age spectrum shows no single affi nity to any of these regions and exhibits zircon ages associated with granitoid rocks representing tectonic events in both west and east northern China. Furthermore, and in contrast to proximal deserts, a signifi cant proportion of zircons from the loess show affi nities with rocks cropping out in the Qilian Mountains. The euhedral form of many of these grains further suggests direct transport from these crystalline source rocks, in contrast to previously hypothesized production or storage in deserts. Thus, dusttransporting storms tracked from the west during the last glacial maximum, although this does not explain all the zircon variability and implies multiple sources and stormtrack variation over the depositional period.

[1] The Cenozoic Song Hong-Yinggehai Basin in the South China Sea contains a large volume of sediment that has been used in previous studies, together with regional geomorphology, to argue for the existence of a large palaeodrainage system that connected eastern Tibet with the South China Sea. To test this and to understand the significance of sediment volumes deposited in the Song Hong-Yinggehai Basin, this study compared erosion histories of source regions with sediment volumes deposited during the two main stages in basin evolution spanning active rifting and subsidence (30-15.5 Ma) and postrift sedimentation (15.5 Ma to present). The study of basin provenance by detrital zircon U-Pb dating revealed Hainan was an important and continuous source of sediment, and a bedrock thermochronological study quantified its overall contribution to basin sedimentation. Comparison between the accumulated mass of basin sediment and volumes of eroded bedrock, calculated from apatite thermochronometry across the modern Red River drainage in northern Vietnam as well as Hainan Island, accounted for the bulk of sediment deposited since 30 Ma. Consequently, if an expanded paleodrainage ever existed it must have predated the Oligocene.