Articles | Volume 7, issue 1
Solid Earth, 7, 191–203, 2016
Solid Earth, 7, 191–203, 2016

Research article 04 Feb 2016

Research article | 04 Feb 2016

Atmospheric significance of aeolian salts in the sandy deserts of northwestern China

B.-Q. Zhu B.-Q. Zhu
  • Key Laboratory of Water Cycle and Related Land Surface Processes, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China

Abstract. Large sandy deserts in the middle latitudes of northwestern China were investigated for soluble salt variations in modern and ancient aeolian sediments, aiming to explore the environmental significance of “aeolian salts”. Results revealed that aeolian salt variations have a clear relationship with the changing meridional and zonal gradients of the desert locations and the aeolian differentiation effect, but are weakly linked to local geological conditions. Atmospheric depositions of water-soluble chemical species are an important process/source contributing to aeolian salt. Sequential variations of soluble salts in sedimentary profiles interbedded with aeolian and non-aeolian deposits and their palaeoenvironmental implications in the hinterland areas of these deserts were further evaluated, based on the constraints of OSL dating and radiocarbon dating data. The results indicate that inorganic salts may be a latent geoproxy in revealing regional palaeoclimatic changes in desert areas for sediments deposited under a single depositional environment, but the interpretation should be more cautious for sediments deposited under diverse depositional conditions. This study presents evidence of the atmospheric origin of aeolian salt in sandy deserts, with limited climatic significance in palaeoenvironmental reconstruction.

Short summary
Salt archives in sediments are critical to understanding a number of geochemical processes in the earth surface conditions. This study presents a physical and geochemical survey into aeolian salts in the Chinese deserts to explore their possible climatic implications. The results suggest the aeolian salts are atmospheric origin without local geological limits. It is a latent indicator in onefold depositional environment but not so in diverse conditions. Palaeoenvironmental use should be careful.