Study on the origin of lithium mineralization in Ba To area, Quang Ngai province
In Vietnam, research on lithium-bearing pegmatites is still quite new, mainly concentrated in the La Vi mine (Ba To, Quang Ngai), which has been licensed to exploit this mineral to produce batteries for the electric car industry. However, previous views on the origin of these pegmatite bodies are still very different. Some hypotheses suggest that they are fractional crystallization products from granitic magma, while others lean towards the possibility of hydrothermal transformation or late greisen-albititization metamorphism. This inconsistency is a major obstacle in assessing reserves and expanding the search for lithium mineral potential in the Ba To area in particular and the Kon Tum block margin in general.
In order to clarify the above issue, Dr. Tran Viet Anh and the research team of the Institute of Geology (now the Institute of Earth Sciences) - Vietnam Academy of Science and Technology have implemented the topic: "Geochemical characteristics, origin and formation process of Lithium mineralization in Ba To area, Quang Ngai, Vietnam" (code VAST05.02/22-23).
Contact boundary between Sa Huynh Complex Granite and Kannack Complex Metamorphic Rock
According to Dr. Tran Viet Anh: Although lithium-bearing granite pegmatite formations are widely distributed in Vietnam, this field has not yet received adequate research attention. Over the years, there have been only a few published works related to lithium mineralization. In particular, in 1971, the late Associate Professor, Dr. Do Thi Van Thanh (University of Natural Sciences, Vietnam National University, Hanoi) mentioned lithium mineralization in pegmatites in the Phu Tho area. Then, in 2004, Associate Professor, Dr. Nguy Tuyet Nhung and colleagues (University of Natural Sciences, Vietnam National University, Hanoi) studied lithium-bearing pegmatite bodies along the Red River suture zone. These records show that the potential of this type of mineral has been recognized for a long time, but there is still a lack of systematic studies to clarify the distribution rules and formation origins, factors that play a key role in orienting the investigation, evaluation and effective exploitation of lithium resources in the future.
In 2023, the Ministry of Natural Resources and Environment (now the Ministry of Agriculture and Environment) approved the scientific task: "Research on the origin, formation conditions and distribution rules of lithium resources in Vietnam". However, according to Dr. Tran Viet Anh: The level of investment is still modest compared to the strategic role of this important mineral. This shows that in-depth research on the origin, potential and distribution rules of lithium in tectonic structural zones in Vietnam is extremely necessary.
Towards that goal, Dr. Tran Viet Anh's team has conducted research with an interdisciplinary approach. Through the research process, the results of geochemistry, geochronology and mineralogy of the project have identified: The origin of lithium-containing pegmatite, one of the key minerals in green energy technology; Classification of the LCT pegmatite system (lithium, cesium and tantalum) in the La Vi mine area (Ba To, Quang Ngai) into 4 different subgroups, based on the symbiotic mineral complex, through petrographic, chemical and isotopic analysis.
Weathered Sa Huynh Complex granite in the survey area
Notably, absolute age analysis using the U-Pb method (one of the oldest and most accurate absolute geological dating techniques available today) showed that both granite and pegmatite formed simultaneously about 250 million years ago. However, the distinct differences in rare element composition and isotope ratios indicate that pegmatite is most likely not directly related to granite. Instead, geochemical signatures have shown that pegmatite was formed from partial melting of metamorphic sediments. The new origin model not only clarifies the formation mechanism of lithium-bearing pegmatite but also provides a scientific basis for expanding the exploration area to areas with similar geological conditions.
U-Pb isotopic age diagram of columbite containing tantalum extracted from pegmatite in the study area
On that basis, the research team has built a complete and systematic geological and mineralogical database for the La Vi mine, including a 1:50,000 scale mineralization diagram and detailed analytical data using modern methods such as LA-ICP-MS to analyze trace elements in mineral samples with high precision and a multi-element isotope system, helping to determine the isotopic ratio and geological origin of the minerals. The research results have been published in an article in the journal LITHOS under the SCIE category.
“We have used a multi-dimensional approach to decode one of the unanswered questions of Vietnamese geological science about the true origin of lithium-bearing pegmatite bodies at the edge of the Kon Tum block. The results show that the pegmatite bodies at the La Vi mine are most likely not fractional crystallization products from granitic magma as previously assumed. If this hypothesis is more clearly confirmed, this could be an important scientific basis for expanding the direction of lithium exploration in Vietnam according to more specific and practical geological criteria,” Dr. Tran Viet Anh added.
The research results have contributed to clarifying the potential of lithium resources, opening up new directions in searching, evaluating and effectively managing rare minerals, serving the development of a green, circular and sustainable economy. Notably, the LCT pegmatite type identified in the Quang Ngai area is not only rich in lithium but also contains other elements of high economic value such as beryllium and light rare earths (typically lanthanum), which are associated minerals with wide applications in the high-tech field. From the results achieved, the group wishes to continue investing to expand the scope of research and evaluation of rare metals associated with lithium in the area, contributing to providing a scientific basis for the rational exploitation and sustainable development orientation of rare resources in Vietnam.
Translated by Quoc Khanh
Link to Vietnamese version
