Episodic fluid decompression drives lithium enrichment in granitic pegmatites
Abstract
Lithium-rich granitic pegmatites supply approximately 50-60% of global Li production, yet the physicochemical mechanisms driving their exceptional Li enrichment remain contested. Here, we integrate cathodoluminescence (CL) imaging and LA-ICP-MS trace element mapping of quartz crystals from miarolitic cavities at the world-class Bailongshan Li deposit (Western Kunlun Orogenic Belt, NW China) to decipher crystallization dynamics during the magmatic-hydrothermal transition. We identify three growth zones composed of a serrated core (Q 1 ) and oscillatory rims (Q 2 /Q 3 ) recording up to ≥5 discrete fluid-pulse events, with Al and Li concentrations spanning two orders of magnitude and co-varying with CL brightness. We demonstrate that episodic fluid pressure drops transiently accelerate crystal growth and thin the chemical boundary layer at the crystal-fluid interface. We interpret this thinning as suppressing diffusive re-equilibration and enabling the kinetic incorporation of coupled Al-Li substitutions into quartz, whereas under steady-state pressure near-equilibrium partitioning inhibits Li uptake. Diffusion modeling supports systematically increasing growth rates from core to rim, consistent with progressive fluid exsolution. Crucially, we show that miarolitic quartz exhibiting ≥5 high-frequency Al-Li oscillation cycles is a robust indicator of rare-metal fertility and enhanced Li-transport capacity, providing an exploration criterion applicable across the world's major Li pegmatite provinces
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BibTeX
@article{hong2026episodic,
title = {{Episodic fluid decompression drives lithium enrichment in granitic pegmatites}},
author = {Tao Hong and Zhang Zhang and Xiao-Yue Ma and Yi Zou and Matthieu Harlaux and Xing-Wang Xu and Jun Gao and Gao-Bin Chu and Ming-Guo Zhai},
journal = {Communications Earth \& Environment},
year = {2026},
month = aug,
doi = {10.1038/s43247-026-03924-y},
url = {https://brgm.hal.science/hal-05845271v1},
note = {CC BY-NC-ND 4.0},
}
RIS
TY - JOUR
TI - Episodic fluid decompression drives lithium enrichment in granitic pegmatites
AU - Tao Hong
AU - Zhang Zhang
AU - Xiao-Yue Ma
AU - Yi Zou
AU - Matthieu Harlaux
AU - Xing-Wang Xu
AU - Jun Gao
AU - Gao-Bin Chu
AU - Ming-Guo Zhai
PY - 2026
DA - 2026/08/22
JO - Communications Earth & Environment
DO - 10.1038/s43247-026-03924-y
UR - https://brgm.hal.science/hal-05845271v1
AB - Lithium-rich granitic pegmatites supply approximately 50-60% of global Li production, yet the physicochemical mechanisms driving their exceptional Li enrichment remain contested. Here, we integrate cathodoluminescence (CL) imaging and LA-ICP-MS trace element mapping of quartz crystals from miarolitic cavities at the world-class Bailongshan Li deposit (Western Kunlun Orogenic Belt, NW China) to decipher crystallization dynamics during the magmatic-hydrothermal transition. We identify three growth zones composed of a serrated core (Q 1 ) and oscillatory rims (Q 2 /Q 3 ) recording up to ≥5 discrete fluid-pulse events, with Al and Li concentrations spanning two orders of magnitude and co-varying with CL brightness. We demonstrate that episodic fluid pressure drops transiently accelerate crystal growth and thin the chemical boundary layer at the crystal-fluid interface. We interpret this thinning as suppressing diffusive re-equilibration and enabling the kinetic incorporation of coupled Al-Li substitutions into quartz, whereas under steady-state pressure near-equilibrium partitioning inhibits Li uptake. Diffusion modeling supports systematically increasing growth rates from core to rim, consistent with progressive fluid exsolution. Crucially, we show that miarolitic quartz exhibiting ≥5 high-frequency Al-Li oscillation cycles is a robust indicator of rare-metal fertility and enhanced Li-transport capacity, providing an exploration criterion applicable across the world's major Li pegmatite provinces
SN - 2662-4435
ER -