Lithium Argentina AG

Tectonic Context

The main lithium-containing region of South America is in the Puna Plateau of the central Andes. The Puna Plateau is approximately 2,000 km long, 300 km wide and has an average elevation of 3,700 masl. The eastern volcanic arc and centres have been active from the Miocene to the present and are the source of mineralized fluids throughout the plateau. The uplift of the Puna Plateau is the result of the crustal shortening that occurred in the Tertiary and magmatic accumulation.

The section of the Puna which developed in Argentina shows distinct features of the Altiplano than those seen in Bolivia and Peru. This zone can be divided into Southern Puna and Northern Puna according to their relative position with respect to the Olacapato lineament. This lineament corresponds to a regional megafracture on a WNW-ESE course that crosses other geological provinces of the Andean axis. The observed geological differentiation in the upper crust is a response to the deep segmentation of the subducted Nazca plate which would condition a different metallogenic development. The southern Puna is considered the plateau region associated with the volcanic arc developed between 24" and 27" S and the Northern Puna to the region between 24" and 22" S.

The volcanic arc limits the Puna hydrological basin to the west while the Eastern Cordillera limits this basin to the east. Towards the Puna Austral (Southern Puna), a combination of east-west striking volcanic chains with uplifted blocks caused by north-south striking reverse faults limit numerous hydrological sub-basins, with numerous and extensive salt flats covering their bases, frequently surrounded by important alluvial systems. Thick sections of Neogene strata (up to 5 km) are present within depositional basins, which contain evaporites (mainly halite, gypsum, and borates) and alluvial clastic material with smaller tuff horizons. Exposed Neogene strata is present along the margins of the salars due to reverse faulting or as intra-basin uplift within the salt flats.