Recent findings from researchers studying pegmatite deposits reveal new insights about the formation of lithium-rich resources, raising important questions about future supply capabilities as the world shifts toward electrification. A study published on the Jiajika pegmatite deposit, situated in the eastern Tibetan Plateau of China, demonstrates how the surrounding country rocks' temperature plays a pivotal role in lithium mineralization.
With the global drive to achieve net-zero fossil fuel emissions by 2050, the demand for lithium—a key component of lithium-ion batteries used for electric vehicles—is expected to soar. According to forecasts from the International Energy Agency, demand could skyrocket 30-fold by 2030 and reach over 100-fold by 2050. This will compound the challenges associated with lithium supply, as more than half of the world's lithium production stems from lithium-bearing pegmatites, yet only specific pegmatites contain economically viable deposits.
The study focuses on the Jiajika pegmatite deposit, which features over 1,000 identified dikes, 30 of which are noted for their high lithium contents. Current estimates suggest the reserve holds about 1.3 million tonnes of lithium, compelling this location to be considered the largest pegmatite deposit globally, surpassing the renowned Greenbushes pegmatite.
Researchers analyzed natural samples from the Jiajika deposit, employing thermal and diffusion modeling to ascertain how lithium abundance relates to the temperature of the surrounding rocks. They found compelling evidence: lithium-rich pegmatites emerge predominantly when low-temperature country rocks are intruded by lithium-rich pegmatite melts. Specifically, they stated, “Lithium-mineralized pegmatites form preferentially when Li-rich pegmatite melts intrude low-temperature country rocks.” This finding reiterates the classic economic zoning pattern seen within pegmatite fields, wherein pegmatites situated farther away from their parent granites are richer in lithium, contrasting with those located close to the heat source.
The higher temperatures prevalent within country rocks proximal to granitic plutons cause significantly more lithium loss during the cooling process of pegmatite dikes. Consequently, this results in lower concentrations of lithium, particularly evident with pegmatite types such as the No. 308 pegmatite studied, which exhibited declining lithium content after intruding warmer country rocks.
Using data from various pegmatite profiles throughout Jiajika, the researchers were able to distinctly show how lithium and its isotopic compositions differ between lithium-rich and lithium-poor pegmatites. Their findings demonstrate: “The lower the temperature of the country rocks, the more favorable the conditions for Li mineralization.” This suggests significant ramifications for exploration strategies targeting lithium deposits, as thermal history emerges as a key determinant for economic lithium concentration.
The results have broader implications for the future study and exploration of lithium resources amid rising global demand due to the transition toward electric vehicles. Knowing the impact of country rock temperature on lithium deposits allows geologists to tailor their exploration efforts more effectively to maximize the chances of identifying lucrative lithium-rich pegmatites.
Overall, this research elucidates the complex interplay between geological processes affecting lithium deposits, shedding light on additional factors influencing pegmatite formation and stability affecting their economic viability. The insights drawn from Jiajika's studies may play a pivotal role as the global market increasingly turns its focus to sustainable electric vehicle technologies, demanding new solutions for lithium supply challenges.