About half of this time water overflowed eastward into Panamint Valley. Old shore lines on the alluvial slopes of the Slate Range to the east show several lake levels including the prominent overflow level. These periods of high lake level coincided with the high precipitation epochs when large glaciers were common in the Sierra Nevada Range of California. The major rocks on the eastern flanks of the Sierra Nevada Range of California are granites and volcanic debris. The adjacent White, Inyo and Coso ranges contributed more volcanic rock, but also sedimentary rock.
Glaciers exert massive forces on the earth and underlying rocks.
As they slowly move down hill, they grind away the rock, reducing much of it to a very fine powder called glacial flour. Gradually, over tens of thousands of years, water from the melting glaciers dissolved many chemicals from the rocks. In fact, everything has some solubility in water. So whatever was in these rocks, some of it was dissolved. Contributing to the chemical load of the runoff water was water supplied by the many volcanic hot springs in the drainage area.