Lithium-bearing micas in the 'Lithium-rich Tuff' from the Macusani Volcanic Field, Puno, Peru

The Falchani Lithium Project has a resource of 0.9 Mt Li hosted in Neogene volcanic tuffs and breccias of the Macusani Volcanic Field. The main host is a newly-defined unit known as 'Lithium-rich Tuff' in which Li contents are mostly between 3,000 and 4,000 ppm. Although this tuff is pervasively altered to clays (dioctahedral smectite and kaolinite subgroup minerals) and zeolites, magmatic zinnwaldite and lepidolite crystals are preserved. The composition of the micas in the 'Lithium-rich Tuff' is systematically more evolved, i.e., richer in Li and other incompatible lithophile elements, relative to micas in other pyroclastic units and nearby intrusive rocks of the Macusani Volcanic Field.