Illitization decrypted by B and Li isotope geochemistry of nanometer-sized illite crystals from bentonite beds, East Slovak Basin

A complementary conclusive aspect of this review is that the smaller the size of the illite crystals and the larger the analyzed field area, the more difficult it becomes to fit the illitization process into a uniform model. The mineral crystallo-chemical variations adapt to changing local conditions during burial and, therefore, re-equilibration of entire crystal populations becomes increasingly difficult to interpret. It is likely that direct analyses at the nano-scale will improve interpretations of variable isotopic tracers, and it is clear that B and Li in illite can be robust indicators of environmental changes over time.