A review of the early Tertiary bauxite event in South America, Africa and India

Abstract

Extensive and thick lateritic bauxites are found in South America, Africa and India. Since Cretaceous times there have been four phases of chemical weathering alternated with erosion phases. It can be shown that the early Tertiary phase generated the thickest soil profiles and the most extensive bauxite deposits; this phase is defined as bauxite event and it relates to a temperature and humidity maximum. The early Tertiary bauxite event also relates to an accumulation maximum of leached elements precipitated in newly formed minerals in basins on the continent, the continental shelf and the deep sea in and around Africa. Using sections from Cutch and Rajasthan/India and South America the event is dated as late Early to early Middle Eocene. The regional distribution pattern of bauxite deposits in South America, Africa and India, when the latter is moved to its early Tertiary plate position, is comparable to known climaticzones. Although it seems that the uplift of the East African Rift Valley has interfered with formation and preservation of extensive bauxites and other lateritic mineral deposits, they may still be discovered when the region is better known geologically.