Where to find Kaolinitic Clays?

There are several favorable environments in nature for the occurrence of kaolinitization process:

  • Hydrothermal processes, related to those areas where rocks of acid / acid-medium composition undergone a transformation process resulting from the action of hydrothermal fluids that ascend to the surface by existing faults in the upper crust. All these factors put together gives rise to a zoning patterns characteristic of this type of geological environment. Specifically, the formation of clay mineral from the kaolinite group is favored under acidic conditions and relatively moderate temperatures
  • Weathering, which is maybe the most important route for the formation of kaolinitic clays at a global scale, especially in tropical and subtropical climatic zones. In these process, the most soluble components of rocks, such as alkalis, are leached out, while the most insoluble components, such as iron and aluminum oxides and hydroxides, remains. Clay minerals of the kaolinite group are among the most common end-products in this type of geological processes.
  • Kaolinitic clays deposits related to flood plains, deltas, among others, where fine-grain sediments could be redeposited. Kaolinite clay minerals, formed by some of the aforementioned kaolinitization processes, are transported by fluvial currents, glaciations, or related phenomena, to slowly form large deposits with relatively high kaolinite mineral content. This type of clay deposits usually has a layer structure, with a variable mineralogical composition as a function on depth.