White Micas as a tool for tracking pegmatite evolution and its use in Li exploration. A case study of Wekusko Lake, Manitoba, Canada.
Abstract
The Wekusko Lake pegmatite field is part of the Green Bay Group of pegmatites located near Snow Lake, Manitoba, Canada. Within this field, there are at least 13 spodumene-bearing pegmatites of varying degrees of mineralization. The abundance of white micas and the chemical affinity to incorporate Li and other trace elements into its crystalline structure makes white micas an ideal indicator mineral. The evolution of a melt can be tracked using trace elements in white mica. The K/Rb ratio vs Cs is used to determine a link between increasing evolution and increased Li contents of both the white mica and the pegmatite. White mica compositions were examined using portable Raman and LIBS to evaluate whether Li contents can be determined in the field. The LIBS was able to identify the pegmatites dikes with the highest Li contents, which can be applied to real-time decision-making during exploration.