The surface features of the quartz sand grains from the Cretaceous desert in the Sichuan Basin

The surface features of quartz sand grains may well be used as the indicators of their depositional environments due to larger hardness and chemical stability. The examination of surface features of quartz sand grains with the aid of scanning electron microscopy is generally viable to the approaches of sedimentary environments. Some of the workers once argued that the Cretaceous strata in the Sichuan Basin should be assigned to the fluvial or delta deposits rather than the desert deposits (Da'erdang and Jiaguan Formations). The previous examination of sedimentary environments was based on sedimentary textures and structures. In the present study, the surface features of quartz sand grains are explored on the basis of the samples from varying levels of the Cretaceous strata in the Sichuan Basin. The exploration of surface features of quartz sand grains has resulted in the recognition of eolian and aqueous deposits. These features of quartz sand grains may serve as the reliable evidences in favour of the presence of the paleodeserts in the basin.