Concentration and distribution of lithium in catchment sediments of China: Conclusions from the China Geochemical Baselines project

With the ever-increasing demand for lithium (Li), understanding its concentration and distribution in the pedosphere is essential for alleviating the Li shortage in China. The China Geochemical Baselines (CGB) project, which commenced in 2008, provided comparable global-scale geochemical Li data. A total of 3394 top (0-25 cm) and 3394 deep (below 100 cm) catchment sediment samples were collected. The range of Li concentrations in the top and deep samples were 5.37-400 mg.kg(-1) with a median value of 30.0 mg.kg(-1), and 5.27-400 mg.kg(-1) with a median value of 28.6 mg.kg(-1), respectively. The Li concentrations in the top and deep catchment sediments of China showed large variations across regions but only mild variability across profiles. Parent rock, especially granite, predominantly governed the Li distribution in the catchment sediments of China. Landscapes, mineralization and weathering played regional-scale roles. Macroscopically, the low background area ( < P25) was mainly distributed in the northern margin of the North China craton, and Hainan Island, and the high background area ( > P75) was mainly distributed in the Allay, South China, Sanjiang and Himalayan orogenic belts, and the Yangtze craton. Based on a cumulative frequency of the 85th percentile, a total of 16 geochemical anomalies were identified, and eight important prospective Li resources were selected where many world-renowned Li deposits were formed.