Microtextural features on quartz grains from eolian sands in a subaqueous sedimentary environment: A case study in the hinterland of the Badain Jaran Desert, Northwest China

Recognizing the sedimentary environments of sand layers in desert areas aids in evaluating the reliability of using these materials to assess paleoenvironmental changes. Nevertheless, determining whether eolian sand has ever been in a subaqueous sedimentary environment remains difficult. The work presented here tests microtextures on quartz grains from a predominantly eolian environment and tries to differentiate grains shaped purely by eolian processes from those also subjected to subaqueous action. In this study, 124 samples including lake sediments, river sediments, and eolian sediments were collected from the Badain Jaran Desert hinterland and adjacentareas. Microtextural assemblages on the quartz grains were analyzed by scanning electron microscopy. The results reveal that the microtextural features have variable frequencies among different sand samples, including lake sediments, eolian sand, and river sand. Eolian sand deposited in a subaqueous sedimentary environment not only has the specific microtextures of subaqueous sedimentary environments such as V-shaped percussion cracks, straight or curved grooves and scratches, oriented etch pits, solution crevasses, and scaling but also retains the unique microstructures of eolian sedimentary environments such as crescentic percussion marks. Therefore, the above microtextural features can distinguish whether eolian sand has ever been in a subaqueous sedimentary environment. This study provides a new method for discriminating the sedimentary environments of eolian sands in desert hinterlands.