Characterization and regional variations in the mineralogical maturity of aeolian sands in northern China

The influences of climate and provenance on desert sediments are an important part of desert research. There are 11 major deserts across northern China, with a total area of 80.89 × 10⁴ km². The effects of climate and provenance on the sediments in these deserts and whether these effects can be reflected by the regional distribution characteristics of a geochemical index are not entirely clear. The mineralogical maturity, which is the degree to which the characteristics of clastic materials approach those of mature sandstone. It is a powerful tool for evaluating the sources, transport, and weathering history of sediments and is an essential geochemical index in desert research. In this study, we calculated the mineralogical maturities of 325 sand samples (125-250 μm) collected from the 11 deserts in northern China. We found that (1) the mineralogical maturity of the desert sediments in northern China exhibits regional variations and increases from west to east (from the Western Deserts to the Central Deserts to the Northeastern Sandy Lands), which corresponds to the humid climate in the eastern part of northern China and the dry climate in the west. From the perspective of the provenance, the higher SiO₂ and K₂O contents of the sediments from the source rocks of the Northeastern Sandy Lands compared to the other two regions cause this trend. (2) The aeolian sediments in northern China have a lower mineralogical maturity compared to other global sediments, especially deserts in the tropics. This phenomenon is consistent with the low level of climatic weathering in temperate deserts, such as the deserts in northern China. (3) Without excluding the influence of global provenance on the mineralogical maturity, it can be tentatively concluded that based on the characteristics of their sediments, the deserts in northern China are in the early stage of desert evolution.