75-4 ANALYSIS OF PEGMATITE K-FELDSPAR BY HANDHELD LASER-INDUCED BREAKDOWN SPECTROSCOPY (LIBS)

Session: Mineralogy, Geochemistry, Petrology, and Volcanology Student Session (Posters)

Presenting Author:

Authors:

Abstract:

Lithium is essential to meeting reduced carbon emissions targets and granitic pegmatites are a principal source of Li. Exploration for Li-enriched pegmatites can benefit from rapid in situ analysis in the field under ambient environmental conditions. Handheld laser-induced breakdown spectroscopy (LIBS) meets this need by providing detection and quantification of the elements important for evaluation of pegmatite mineralization (e.g. Li, K, Rb) when a Li-bearing phase is not present in outcrop. Building on recent work demonstrating that K/Rb-Li systematics in muscovite can provide insight into the extent of pegmatite fractionation and spodumene mineralization potential (e.g., Wise et al., 2024; Curry et al., 2024), this project investigated whether similar systematics might apply to potassium feldspar and whether other elements might be useful in the same context. A large collection of pegmatite K-feldspars of known composition from LA-ICP-MS analysis were used to calibrate a handheld LIBS analyzer for the quantification of Li, K, and Rb as well as selected minor and trace elements (Na, Mg, P, Ca, Ga, Sr, & Ba). Calibrations were optimized by normalizing selected element emission lines to reference peaks from the same spectrometer on the LIBS analyzer. Results using these calibrations suggest that both K/Rb-Li and Li-Sr-Ba systematics can differentiate between Group 1 and Group 2 pegmatites (Wise et al., 2022) as well as spodumene-mineralized and unmineralized pegmatites.

Geological Society of America Abstracts with Program. Vol. 57, No. 6, 2025

doi: 10.1130/abs/2025AM-5977

© Copyright 2025 The Geological Society of America (GSA), all rights reserved.