Recently, the demand for lithium (Li) as an energy storage element has increased, owing to the rapid increase in the number of electric vehicles. To meet this demand, Li exploration has become increasingly important. The Boam deposit is located in the Uljin area of eastern South Korea, where several rare-element pegmatites (0.24% Li) intrude the Precambrian Janggun Limestone Formation. In this study, we performed petrographical and geometrical analyses of the rare-element pegmatites recognized in the vicinity of the Boam deposit, through which the Li-mineralization process was identified and the factors controlling intrusion studied. Our results are summarized as follows: (1) the pegmatites exhibit regional and internal zoning based on their mineral assemblages; (2) Li mineralization is restricted to pegmatites; (3) the geometry and distribution of the pegmatites are strongly controlled by fracture, bed contact, and post-intrusive deformation; and (4) exploration should be concentrated in the ENE–WSW-trending zone of the upper part of the Janggun Limestone Formation. These results provide valuable understanding to guide the development of strategies for early-stage mineral exploration in the Uljin area.

Cretaceous igneous rocks are concentrated in the northern Taebaeksan metallogenic region of South Korea, some of which are related to Fe skarns and/or hydrothermal vein Au–Ag deposits. However, detailed studies on the emplacement age and magma source of igneous rocks supplying this metallogenic area are lacking. In this study, we investigated the emplacement age, magma sources, and geochemical characteristics of seven Cretaceous igneous rocks around the ore deposit, comparing them with previous studies. Zircon U–Pb and mica K–Ar age dating indicated that two magmatism events occurred in the Early Cretaceous (~113.7 ± 0.2 to 104.7 ± 0.5 Ma) and the Late Cretaceous (~85.8 ± 1.1 to 77.6 ± 0.4 Ma). Negative ɛHf(t) values (−2.57 to −22.05 approx.) and the calculated (2.55–1.33 Ga) suggested that the magma source of these igneous rocks was derived from the Proterozoic crust. Whole‐rock geochemical data indicated that the northern Taebaeksan igneous rocks are mostly high‐K calc‐alkaline series, enriched in light rare‐earth elements (LREEs) and large‐ion lithophilic (LIL) elements but depleted in high‐field‐strength (HFS) elements. Although igneous rocks in the northern Taebaeksan metallogenic region have broadly similar magma source characteristics, they can be classified into two groups: one comprises Early Cretaceous intermediate rocks, some of which are related to Au–Ag mineralization, whereas the other includes Late Cretaceous intermediate to felsic rocks, related to Au–Ag or Fe mineralization.

Eunjeok Au–Ag deposits are situated in the Yeongam district, Cheollanamdo-province, South Korea. They are genetically related to the Bulgugsa magmatic event (ca. 110–60 Ma), caused by the transition in the subduction direction and style of the Izanagi Plate. Three gold- and silver-bearing hydrothermal veins filled the fractures of the Cretaceous rhyolitic tuff. The major ore minerals were arsenopyrite (31.47–32.20 at.% As), pyrite, chalcopyrite, sphalerite (8.58–10.71 FeS mole%) and galena with minor amounts of electrum (62.77–78.15 at.% Au), native silver, and argentite. Sericitization was dominant in the alteration zone. The various textures of quartz veins (i.e., breccia, crustiform, comb, and vuggy) may indicate the formation of an epithermal environment. The auriferous fluids with the H₂O–NaCl system have homogenization temperatures and salinities of 204 °C to 314 °C, less than 10 wt.% equiv. NaCl, and experienced mixing (dilution and cooling) events during mineralization. Considering the characteristics of the geologic setting, major fault system, and host rock, the Eunjeok Au–Ag deposit within the Yeongam district tends to share the general geologic characteristics of Haenam–Jindo epithermal mineralization episodes. However, the age of gold–silver mineralization (86.0 Ma) is older than that of Haenam–Jindo epithermal mineralization episodes (<70.3 Ma), implying some differences exist in the genetic sequence of extensional characteristics caused by transcurrent Gwangju–Yeongdong faults.

Il-Hwan Oh, Gyuseung Park, Sang Joon Pak, Chul-Ho Heo, Bum Han Lee. Econ. Environ. Geol. 2025;58:491-500. https://doi.org/10.9719/EEG.2025.58.5.491

The occurrence mode of lithium, a critical element in the battery industry, can be categorized into three types. Among these, the hard rock-type, particularly the LCT (Lithium-Cesium-Tantalum) pegmatites, stands out for its exceptional cost-effectiveness and developmental efficiency. LCT pegmatites originated from S-type granites; they exhibit compositional characteristics consistent with fertile granite and are enriched in Li, Cs, Be, Sn, Ta>Nb, B, P, and F. Leveraging these geochemical attributes, LCT pegmatites can be effectively explored by considering distinct factors such as the distribution of source rocks, geotectonic environment, and age dating. Current research deals with LCT pegmatites located in Uljin, South Korea, employing appropriate exploration methods including geophysical exploration and structural and geochemical analysis. The future objective involves constructing a 3D subsurface orebody model through the spatial integration of data derived from various exploration methods.