Where is Lithium Found?

On salt flats usually.  Sometimes in ancient granitic rocks, where it is mined in pits. Or maybe in clay deposits, where it is also mined in pits, crushed, washed, and treated.

Salt flat lithium is produced in brine. This liquid is brought to the surface in water wells, the lithium is extracted from the fluid and the brine is returned to the reservoir from which it came.

Lithium is abundant, but not concentrated. It has erupted from the Earth's interior, by way of volcanic outpourings and has been displaced almost everywhere.  Its concentration in the oceans is about 20 parts per million.  Certain types of volcanic rocks are more enriched than others, particularly the rhyolite variety, which is abundant on the Tibetan Plateau, parts of outer Mongolia, the high Andes mountains, and central Nevada.

Below is a Google Earth image of an odd volcanic rock that crops out at the surface, called a "basaltic tuff".  This rock was deposited as an air-fall deposit that erupted from an explosion about 3 million years ago that covered several thousand miles of the Earth's surface near Railroad Valley, Nevada.  The chemistry of this basaltic tuff is unique and it is related to oceanic rocks that were subducted beneath Nevada.  These rocks tunneled upwards from very deep in the Earth's mantle before erupting.  The diagram below the photo image is a cross section of the rocks, and shows their dip into the subsurface, their thickness, and associated rocks.  It is super-exciting to touch these rocks!

Basalt tuff

The great lithium deposits of the world - Atacama, Hombre Muerto, Zabuye - are concentrations that formed from the evaporation of lakes into salt flats.  Giant lakes, that covered thousands of square miles and had no outlet, then dried to small residual ponds of a few tens of miles in size, collecting perhaps 5 or 10 feet of thickness each 25,000 years.  This cycle of filling and evaporation repeated dozens or hundreds of times, forming thick evaporite sequences of complex salts.  Lithium, washed into these lakes as one of the many salts, is the last to precipitate during evaporation.