Quantitative constraints on the environmental conditions of bauxite formation since Mesozoic

The bauxite is a critical paleoclimatic proxy, and it is also the main material for refining aluminum. Therefore, it is of great scientific, economic and strategic significance to study the mineralization of bauxites. The formation of bauxites is largely affected by intense chemical weathering, closely related to temperature, precipitation and vegetation cover. In paleoclimatic studies, bauxites are used to qualitatively indicate warm, humid and vegetated environmental conditions, but how bauxites in the deep time were quantitatively related to temperature and precipitation has not been established, which limits the paleoenvironmental indication of bauxites and the metallogenic prediction. Here, we combine geological records with climate simulations to establish the quantitative relationships of bauxites with temperature and precipitation since the Mesozoic era. The Earth system model CESM1.2.2 and the vegetation model BIOME4 were combined to simulate the climate and vegetation distribution. Then the environmental information of the paleo-locations of bauxites is extracted, and the quantitative relationships between bauxites, and temperature, precipitation and vegetation are established. We show that bauxites formed with an annual mean temperature of 24.8 °C and precipitation of 1097 mm y-1 after 250 Ma. The climatic variations of bauxites are due to land distribution, climate states, and vegetation coverage. Our research results provide a new understanding of the mineralization of bauxites, and also offer a reference for the exploration of bauxites.