The behavior of thallium during alteration of the K-alkaline rocks from the Roccamonfina Volcano (Campania, southern Italy)

Tl behavior in the alteration of leucite and related K-alkaline rocks from the Quaternary Roccamonfina Volcano has been outlined. The dominant weathering product is analcite, that shows a moderate loss of Tl relative to the coexisting leucite (R̄= 0.74 ± 0.21). Weathering of leucite to halloysite is subordinate and characterized by a very strong depletion in Tl (R̄= 0.14 ± 0.15).