Abstract: Potential New Sources for Lithium in Brines and Sedimentary Rocks

James D. Vine

Traditional sources for lithium have been lithium minerals, notably spodumene, form granite pegmatites and lithium-rich subsurface brines in playa deposits of the southwestern United States. Extension of known pegmatite districts in North Carolina and of brine fields in Nevada will continue to be the principal sources for lithium in the United States until new districts or new types of deposits are identified. Lithium-rich brines are known in nonmarine salt basins, in vapor-dominated geothermal systems, and in oil-field formation waters associated with marine evaporites. Volcanic activity and basin-and-range faulting are closely associated with the first two, but not with the third. A possible mechanism for the concentration of lithium in oil-field formation waters may be remobilization of lithium originally concentrated with the residual bitterns of evaporite basins and entrapped in the crystal mush of gypsum and halite. This lithium could be readily dissolved and mobilized by water of dehydration when gypsum is converted to anhydrite by burial metamorphism. Lithium-rich altered volcanic rocks and clay minerals associated with former lithium-rich brines constitutes another potential source. There are many deposits of this type in the western Great Basin of Nevada; the Mojave Desert of California; the late Cenozoic basins of Arizona, Utah, and Wyoming; the High Plains of Texas; and the coalfields of Pennsylvania; but they have yet to be evaluated adequately. Each lithium localization in a sedimentary environment represents a different problem with respect to origin, mineralogy, mining, and extraction.

AAPG Search and Discovery Article #90968©1977 AAPG-SEPM Annual Convention and Exhibition, Washington, DC