Abstract
Petalite is one of the major lithium aluminosilicate minerals occurring in Li-rich granitic pegmatites. Experiments have been carried out at a confining pressure of 1.5 kbar, and at 450 °C and 600 °C to study the equilibrium between petalite, albite, quartz, and the coexisting chloride solution. Very little Na or Li enter the structure of petalite or albite respectively. When petalite coexists with albite and quartz, the alkali composition of the fluid is buffered. The value of the Na/(Na + Li) ratio of the fluid has been determined to be 0.520 ± 0.020 at 450 °C and 0.545 ± 0.015 at 600 °C in the buffered medium. This indicates that temperature has only a very slight influence on the composition of the buffered solution under the given experimental conditions.
