명보라 Bora Myeong , 박수민 Sumin Park , 장윤득 Yun-deuk Jang

DOI:10.22807/KJMP.2026.39.1.1 Vol.39(No.1) 1-17, 2026

High-silica granites (SiO₂>70 wt.%) are commonly interpreted as evolved melts produced by crystal-melt segregation within shallow, rhyolitic magma storage systems in the upper crust. This study aims to constrain the petrographic and geochemical characteristics and petrogenesis of fine-grained alkali-feldspar granites exposed in the central part of the Daeunsan volcanic caldera, southeastern Gyeongsang Basin, hereafter referred to as the Daeunsan high-silica granite (DHG). We conducted field investigations, petrographic observations of thin sections, whole-rock analyses of major and trace elements, and SHRIMP zircon U-Pb age dating. The DHG is a miarolitic, leucocratic granite, composed mainly of quartz and alkali feldspar with minor biotite. The whole-rock compositions are characterized by its high silica contents (SiO₂= 74-78 wt.%) and Ga/Al ratios, but relatively low Ba, Sr, and Eu contents. In granite discrimination diagrams, its samples are plotted within the A-type granite field, whereas volcanic-arc granite affinities are predominantly shown in tectonic discrimination diagrams. The weighted mean ²⁰⁶Pb/²³⁸U age of zircon, 48.2±0.5 Ma, indicates its Eocene emplacement. Rayleigh fractional crystallization modeling suggests that the DHG represents a product of differentiated melts formed after 20-40% fractionation from its silicic parental magma. Geochemical characteristics of the DHG are comparable to those of the Gyeongju high-silica granites, both of which collectively originated from the melt-extraction of a shallow-crustal crystal mush system in a volcanic-arc setting. Moreover, the temporal continuity between the emplacement of the DHG and repeated reactivation of the nearby Yangsan Fault system implies that regional-scale tectonic palaeo-stresses may have contributed to crystal mush deformation and enhanced melt segregation and extraction. This study demonstrates that the geochemical features of high-silica granites can be more strongly controlled by magmatic differentiation within crustal storage systems, than by the specific tectonic environment during petrogenesis.

고-실리카 화강암, 결정죽, 규장질 누적암, 결정-멜트 분리, 멜트 추출, High-silica Granite, Crystal Mush, Felsic Cumulate, Crystal-liquid Separation, Melt Extraction

김성용 Seong-yong Kim , 허철호 Chul-ho Heo

DOI:10.22807/KJMP.2026.39.1.19 Vol.39(No.1) 19-27, 2026

Based on innovation in geological theories, prediction and exploration models, and comprehensive GIS-based assessment methodologies, China has conducted evaluations across 25 first-level prospective mineralization belts within the country. It is estimated that approximately 65% of China’s undiscovered ore deposits are located within 2 kilometers below the surface. A large proportion―over 60%―of the undiscovered mineral resources for REE, tungsten, tin, iron, copper, aluminum, potassium, lead-zinc, and gold are assessed to be high. Recently, China has designated 195 prospective prediction ore deposits for metallic minerals and 130 for non-metallic minerals. China is also actively promoting the exploration and mining of mineral resources in deep-sea areas and outer space. They are applying the latest Chinese geophysical electromagnetic exploration techniques, such as magnetotelluric and transient electromagnetic methods, to search for new ore bodies. Furthermore, China is pursuing a digital-driven exploration strategy aimed at systematically structuring existing unstructured text data. To this end, they are developing named entity recognition (NER) technology for mineral exploration literature. This technology seeks to automatically extract core information such as mineral names, locality names, deposit types, and geological units.

중국, 광상, 광화대, 탐사전략, 탐사개발, China, ore deposits, mineralization belts, exploration strategy, exploration and mining

황지애 Ji Ae Hwang , 권희원 Hee Won Kwon , 김영훈 Young Hun Kim , 김정진 Jeong Jin Kim

DOI:10.22807/KJMP.2026.39.1.29 Vol.39(No.1) 29-39, 2026

In this study, iron oxides/oxyhydroxides were synthesized under controlled pH conditions (4.0-14.0) and reaction times (1 h and 24 h), and systematically evaluated their mineralogical, physical, and heavy metal adsorption characteristics. The synthesized iron oxides/oxyhydroxides consisted mainly of goethite under pH 4.0-6.0 conditions and magnetite under pH ≥ 8.0 conditions, and increasing reaction time led to higher crystallinity and a decrease in specific surface area. The heavy metal adsorption experiments showed that As was selectively removed from mixed heavy metal aqueous solutions, and in particular, the low-crystallinity goethite sample synthesized at pH 6.0 for 1 h exhibited the highest As removal efficiency. The adsorption efficiencies of Pb, Cd, Cu, and Hg by the synthesized iron oxides/oxyhydroxides were generally low. This study provides important implications for the potential reuse of iron oxides/oxyhydroxides, which are by-products of acid mine drainage treatment, by exploiting their selective As adsorption properties generated through pH and reaction time control under synthesis conditions.

합성, 철 산화/수산화물, 침철석, 마그네타이트, 중금속 흡착, synthesize, iron oxides/hydroxides, goethite, magnetite, heavy metal adsorption

Gerica Joie P. Castro , 권기덕 Kideok D. Kwon

DOI:10.22807/KJMP.2026.39.1.41 Vol.39(No.1) 41-57, 2026

Clay mineral-fluid interfaces govern key geochemical processes in soils, sediments, and engineered systems. While experiments provide valuable structural insights, they have limitations in quantifying the thermodynamic driving forces (free energy) that govern chemical reactions at these interfaces. Recent advances in atomistic simulation have enabled precise characterization of thermodynamic mechanisms at clay mineral interfaces at the molecular level that are challenging to obtain experimentally. This review introduces free energy calculation techniques based on atomistic simulations and examines research cases utilizing these methods for clay mineral-fluid interface studies. We discuss the potential applications and contributions of atomistic free energy calculations in predicting contaminant behavior, radioactive nuclide sequestration, remediation, and engineered barrier material design. Finally, we provide perspectives on the free energy calculation methodologies for integration with experimental analysis in clay mineral interface research.

free energy, molecular dynamics simulations, clay minerals, interface, 자유에너지, 분자동역학 시뮬레이션, 점토광물, 계면

유봉철 Bong Chul Yoo

DOI:10.22807/KJMP.2026.39.1.59 Vol.39(No.1) 59-71, 2026

The Gubong Au-Ag deposit consists of eight quartz veins that fill fracture zones developed within Precambrian metasedimentary rock. The wall-rock alteration zone of the deposit contains white mica, chlorite, zircon, rutile, ilmenite, monazite, apatite, thorite, pyrite, chalcopyrite, quartz, calcite, and albite. Zircon occurs either as isolated grains within white mica or as euhedral to subhedral crystals enclosed in or adjacent to rutile.Based on the occurrence of zircon, it can be inferred that zircon formed through dissolution and reprecipitation of pre-existing zircon associated with the formation of Ti oxides (rutile and ilmenite) resulting from hydrothermal alteration (chloritization) of Ti-enriched biotite in the host rock. This interpretation is consistent with recent studies demonstrating that zircon, rutile, apatite, and monazite can crystallize autigenically or develop overgrowths during fluid-rock interaction processes. Zircon from the Gubong Au-Ag deposit is composed predominantly of ZrO₂ and SiO₂, with minor amounts of HfO₂ (1.21∼2.12 wt.%), TiO₂ (0.00∼0.15 wt.%), ThO₂ (0.00∼1.03 wt.%), Y₂O₃ (0.00∼2.44 wt.%), Nb₂O₅ (0.00∼0.23 wt.%), P₂O₅ (0.0∼2.03 wt.%), FeO (0.12∼0.24 wt.%), and lanthanides (0.49∼1.55 wt.%). In particular, The HfO₂ contents of zircon from this deposit differ from those of typical hydrothermal zircon, suggesting intensive chemical re-equilibration of metamorphic zircon rather than a purely hydrothermal origin. Zircon from the Gubong Au-Ag deposit is therefore interpreted to have originated from metamorphic zircon subsequently modified by hydrothermal processes, where interaction with Au-Ag-bearing fluids during wall-rock alteration under progressively increasing pH conditions facilitated the enrichment of Y, P, Nb, Ti, and lanthanide elements within zircon. The trace element substitution mechanisms indicate that Hf, Th, and Ti are predominantly incorporated through simple substitution and coupled substitution involving at an interstitial site, whereas Ca, Y, REE, Al, As, Bi, Fe, Nb, and P are preferentially incorporated through xenotime substitution and coupled substitutions involving at one structural site, at two structural sites, and at an interstitial site. In summary, zircon from the Gubong Au-Ag deposit originated from metamorphic zircon in the host metasedimentary rock and was formed through dissolution and reprecipitation processes accompanied by redistribution of these trace elements during interaction with Au-Ag-bearing hydrothermal fluid. This provides useful indicator information for tracing the geochemical characteristics of Au-Ag-bearing hydrothermal fluid (redox conditions, pH, phosphate/REE mobility, and Ti-oxide association) and the early stage of ore formation.

구봉 금-은 광상, 저어콘, 산상, 화학조성, 치환 메커니즘, Gubong Au-Ag deposit, Zircon, Occurrence, Chemical composition, Substitution mechanism

김영훈 Young Hun Kim , 권희원 Hee Won Kwon , 김정진 Jeong Jin Kim

DOI:10.22807/KJMP.2026.39.1.73 Vol.39(No.1) 73-83, 2026

This study investigated the remediation mechanisms of high-concentration heavy metal-contaminated groundwater (HCHGW) by selecting Ca-based carbonate minerals (calcite and aragonite) and adsorptive silicate minerals (montmorillonite and zeolite), as reactive media. The main constituent minerals of the Ca-based carbonate minerals used in the experiments were calcite and aragonite. The adsorptive silicate minerals consisted of montmorillonite and zeolite minerals, specifically mordenite and clinoptilolite. The results of the reaction experiments showed that the Ca-based carbonate minerals caused a rapid increase in pH during the initial reaction stage. Aragonite exhibited the highest removal efficiency for Zn, indicating a difference in reactivity compared to its polymorphic mineral, calcite. In contrast, the adsorptive silicate minerals, montmorillonite and zeolite, showed a limited pH-increasing effect and generally low removal efficiencies. In the NaOH pretreatment experiments, the Ca-based carbonate minerals exhibited high removal efficiencies for Cd and Zn, while Cu and Fe were mostly removed by pH adjustment alone. However, the adsorptive silicate minerals, montmorillonite and zeolite, showed low heavy metal removal efficiencies. The removal of heavy metals from HCHGW is considered to be governed primarily by precipitation reactions induced by pH increase rather than by adsorption reactions.

중금속, 아라고나이트, 방해석, 몬모릴로나이트, 제올라이트, heavy metal, aragonite, calcite, montmorillonite, zeolite

류충렬 Chung-ryul Ryoo , 하상민 Sangmin Ha , 임현지 Hyeonjee Lim , 한종원 Jongwon Han , 이태호 Tae-ho Lee , 손문 Moon Son , 강희철 Hee-cheol Kang

DOI:10.22807/KJMP.2025.39.1.85 Vol.39(No.1) 85-93, 2026

We report two Quaternary faults developed in the southernmost part of the Yangsan Fault Zone, Korea. These faults displace unconsolidated conglomerates on a construction slope around Gasan-ri, Yangsan, Korea. The unconsolidated conglomerates cut by the faults are mainly composed of granitic boulders with a diameter of 20-60 cm, sometimes more than 1 m, which are likely derived from Mt. Geumjeong. The faults strike the NE to ENE (N45º-60ºE, ‘Gasan Fault’) and the NNE (N20º-26ºE, ‘Geumsanri Fault’), respectively, and dip to the NW with high angles (75º-85º). The faults show apparently the top-up-to-the-east reverse faulting geometry. However, the slip senses observed near the fault surfaces indicate a dextral reverse movement in the Gasan Fault and a sinistral shearing with a reverse-slip component in the Geumsanri Fault during the Quaternary. The vertical separations of the faults, calculated from the offset of the different layers of unconsolidated sediments/basement, were estimated to be from 1 to 5 m.

양산단층, 양산, 가산리, 제4기 단층, 미고결 역층, 역단층성 주향이동운동, Yangsan Fault, Yangsan, Gasan-ri, Quaternary fault, unconsolidated conglomerate, oblique reverse faulting

박보경 Bogyeong Park , 김은정 Eun Jeong Kim , 김현나 Hyun Na Kim , 이범한 Bum Han Lee

DOI:10.22807/KJMP.2026.39.1.95 Vol.39(No.1) 95-103, 2026

The water content of montmorillonite is known to vary with relative humidity (RH), which in turn influences its physical properties. Two common methods are used to control RH: the saturated salt solution method and a direct humidification method in a glove box. However, a direct comparison between these two methods has not yet been conducted. In this study, we investigated the effects of RH control methods and the effect of interlayer cations on the water content of montmorillonite. High-purity Na-montmorillonite (Kunipia-F), Na-montmorillonite, and Ca-montmorillonite were hydrated under various RH conditions, and their water contents were analyzed using thermogravimetric analysis (TGA) and derivative thermogravimetric analysis (DTG). The TGA results of Kunipia-F hydrated by the saturated salt solution method and the direct humidification method in a glove box showed that the difference in water content is approximately 1 wt% at an RH of 50 ± 2% and the weight loss patterns are identical for both methods. These results indicate that the same hydration species are formed, and the direct humidification method in a glove box is a reliable approach for investigating the hydration behavior of montmorillonite. The water content of montmorillonite increases with increasing RH, and Ca-montmorillonite exhibits 3-6 wt% higher water content than Na-montmorillonite under the same RH conditions. The influence of interlayer cations on water content becomes more pronounced under low-humidity environments. DTG analysis reveals dehydration peaks at approximately 60 ℃ and 80 ℃ for Na-montmorillonite, whereas an additional dehydration peak near 150 ℃ is observed for Ca-montmorillonite, indicating differences in interlayer hydration structures depending on the interlayer cation species. These results demonstrate that the hydration properties of montmorillonite are strongly influenced by RH and interlayer cations, suggesting that RH variations may affect the physical properties of clay minerals in geological environments.

몬모릴로나이트, 벤토나이트, 상대습도, 함수량, 열중량분석, montmorillonite, bentonite, relative humidity, water content, thermogravimetric analysis