Changes in inorganic carbon storage and the potential capacity of sequestration of secondary carbonate in the deserts, with a special reference to the Badain Jaran Desert, western Inner Mongolia, China

Various studies have shown that the concentration of calcium carbonate in the surface layer changes regionally in relation to annual mean precipitations in arid and semi-arid zones. It is also widely assumed that the global climate changes are to a considerable degree triggered by the fluctuations of carbon dioxide in the atmosphere. Through the exchange of calcium ions, the weathering processes of silicate rocks could have a decisive impact on the concentration of the carbon dioxide in the atmosphere. This paper is intended to study the Quaternary changes of the inorganic carbon storage in deserts in order to make a better understanding of the quantitative contribution of deserts to the carbon cycles. Here we present firstly the regional variations of calcium carbonate in sand samples collected from various deserts of northern China, and then estimate the percentage of secondary carbonates in these desert sands and the sources of calcium ions on the basis of the oxygen, carbon and strontium isotopes. According to these kinds of isotopic data from northern China it can be concluded that the changes of desert landscape, in response to global and regional climate fluctuations, could play a quite significant role in the quantity of sequestration and emission of carbon dioxide globally even on a shorter time scale.