Distribution and genesis of global Na-carbonate deposits and its prospecting potential

This paper is the result of mineral exploration engineering.

Objective Natural soda-ash deposits, also called sodium carbonate evaporites, are mainly used to produce soda ash. In the soda industry, compared with synthetic soda, this process has advantages for environmental protection and lower cost. The downstream industries contain various fields, including glass, medicine, and so on. The booming of new energy industries such as photovoltaic has brought new demand for soda ash. China consumes loads of soda ash annually; thus, soda may become a scarce resource in the future. Mineralization process of natural soda-ash evaporites is of great significance in evaporite community. In China however, soda-ash deposits have received little attention and have great research potential. Investigations on types and distribution characteristics of global soda-ash deposits and their genesis are helpful and useful for deepening research and prospecting of Nacarbonate deposits in China.

Methods Compiling published data and systematically summarizing the regional setting, provenance, genesis of typical soda-ash deposits.

Results Most deposits are Cenozoic in age and located in North America, Asia and Africa. Modern soda-ash deposits predominate in number, but resources size of ancient deposits is tremendous. Specific ancient deposits include the Green River Formation, United States and the Anpeng soda deposit in Biyang Depression in Henan, the counterparts, typical modern alkaline lake deposits formed in Lake Magadi, Kenya and Chaganor, Inner Mongolia.

Conclusions The requirement for Na-carbonate deposits precipitation are (1) hydrologically-closed basins, (2) arid climate, and (3) sufficient sodium carbonate supply. Unlike other evaporites, the sources of CO₂ required to maintain Na-carbonate brines are complicated. Efforts for prospecting in China should focus on Quaternary saline lakes, Cretaceous restrict basins in Inner Mongolia, and tectonically-closed depression in which dolomite and oil shale develops in Henan. It is of great significance to carry out the metallogenic theory research and mine prospecting.