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

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

Poster Booth No.: 297

Presenting Author:

Robert Ramos

Authors:

Ramos, Robert Michael¹, Harmon, Russell S.², Wise, Michael A.³, Curry, Adam C.⁴

(1) Department of Marine, Earth, and Atmospheric Sciences, North Carolina State University, Raleigh, NC, USA, (2) Department of Marine, Earth, and Atmospheric Sciences, North Carolina State University, Raleigh, NC, USA, (3) Department of Mineral Sciences, National Museum of Natural History, Smithsonian Institution, Washington, DC, USA, (4) North Carolina Geological Survey, Raleigh, NC, USA,

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

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

Description

Session Format: Poster

Presentation Date: 10/19/2025

Presentation Room: HBGCC, Hall 1

Poster Booth No.: 297

Author Availability: 3:30–5:30 p.m.

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