김태환 Taehwan Kim , 이유영 Yuyoung Lee

DOI:10.22807/KJMP.2025.38.2.77 Vol.38(No.2) 77-79, 2025

이병춘 Byung Choon Lee , 강민수 Min Su Kang

DOI:10.22807/KJMP.2025.38.2.81 Vol.38(No.2) 81-92, 2025

The calculation of phase equilibrium through thermodynamic modeling provides insights into the metamorphic pressure-temperature condition as well as various physicochemical data (e.g., metamorphic pressuretemperature path, partial-melting temperature, evolution process of melt, mineral composition activity, oxygen fugacity, etc.). Therefore, interpreting the temperature-pressure-composition conditions of specific metamorphic mineral assemblages based on petrographic observations and phase equilibrium diagram is essential for understanding the evolution of metamorphism. This paper aims to expand the use of phase-equilibria modelling by introducing the procedure and application of the THERMOCALC software, along with practical guidelines and precautions for its use.

변성암, 열역학 모델링, THERMOCALC, Metamorphic rock, Thermodynamic modelling

이정민 Jeongmin Lee , 김형수 Hyeong Soo Kim

DOI:10.22807/KJMP.2025.38.2.93 Vol.38(No.2) 93-109, 2025

Phase equilibrium modeling is widely used to quantitatively interpret equilibrium reactions during metamorphism and to constrain metamorphic pressure-temperature-composition (fluid or chemical composition) (P-T-X) conditions and tectonic evolution. P-T, T-X, and P-X pseudosections, calculated based on the bulk composition of metamorphic rocks, have been widely applied to P-T-X conditions during metamorphism. This study describes the method for constructing a P-T pseudosection using the Perple_X program and outlines the procedure for calculating the volume (isomode) and composition (isopleth) of metamorphic minerals. A pressure-temperature pseudosection is constructed through three main steps. First, the ‘build’ application is used to define the key modeling components such as thermodynamic database, model system, equation of state, bulkrock composition, range of intensive and extensive variables, and solid solution models. These inputs are used in the ‘vertex’ application to calculate stable phases assemblages through Gibbs free energy minimization. The calculated results are visualized as a pressure-temperature pseudosection using the ‘pssect’ application. The volume (isomode) and chemical composition (isopleth) of metamorphic minerals are calculated using the ‘werami’ application, and visualized through the Python-based tool, ‘pywerami’. To construct a pseudosection for the representative metamorphic mineral assemblages of the studied rock, it is essential to define an appropriate chemical system and bulk rock composition, and to select suitable thermodynamic data base and solid solution models. Interpretation of pseudosection modeling results requires consideration of the incomplete equilibrium typically achieved in natural rocks, and should be supported by detailed petrographic and microstructural observations.

상평형도 계산 프로그램, Perple_X, 광물 등모드선, 광물 등성분선, Phase equilibrium modeling program, Mineral mode isoline, Isopleth

박규찬 Gyuchan Park , 임성환 Sunghwan Im , 박정우 Jung-woo Park

DOI:10.22807/KJMP.2025.38.2.111 Vol.38(No.2) 111-131, 2025

alphaMELTS 1.9 is a modelling program designed to simulate magmatic processes under various geological settings, based on the thermodynamic models, MELTS, pMELTS, and pHMELTS. The text-based interface and compatibility of alphaMELTS 1.9 with both Windows and Mac systems offer greater accessibility and usability, compared to conventional thermodynamic models. This paper outlines the installation procedure and basic usage of alphaMELTS 1.9, and provides guidance on troubleshooting common execution errors. Additionally, it presents examples that implement representative magmatic processes―including equilibrium and fractional crystallization, assimilation-fractional crystallization, equilibrium, continuous and fractional melting, and flux melting―using alphaMELTS 1.9. Furthermore, the modelling results are compared with natural sample data. This study aims to assist researchers in utilizing alphaMELTS 1.9 for understanding the magmatic processes and evolution of mantle and crust.

열역학 모델, alphaMELTS, 분별 결정 작용, 맨틀 용융, Thermodynamic model, Fractional crystallization, Mantle melting

김태환 Taehwan Kim

DOI:10.22807/KJMP.2025.38.2.133 Vol.38(No.2) 133-145, 2025

The Theriak/Domino software performs thermodynamic phase-equilibria modeling based on the Gibbs free energy minimization. As a function of variable P-T conditions at a given bulk-rock composition, the software calculates and visualizes the equilibrium mineral assemblage of metamorphic rocks. Theriak is responsible for computing the stable assemblage using a thermodynamic database, while Domino handles the graphical output. Compared to other metamorphic thermodynamic modeling programs, Theriak/Domino is user-friendly because of its light system requirements and comprehensive user manual. In addition to official guidebook, this paper provides a step-by-step introduction to the software, from downloading through setting up to prepare input data such as bulk-rock composition and thermodynamic database, to showing how to run the program via the command prompt for primarily constructing pseudosections. Theriak/Domino further offers other tools such as plotting isopleths. Beginners are strongly encouraged to refer previous studies on rocks with similar compositions to their target samples. The use of Theriak/Domino is expected to contribute significantly to expanding the foundation of metamorphic petrology research in Korea.

Theriak, Domino 소프트웨어, 열역학 모델링, 전암 조성, 열역학 데이터베이스, 변성암, Theriak, Domino software, Thermodynamic modeling, Bulk-rock composition, Thermodynamic database, Metamorphic rocks

조문섭 Moonsup Cho

DOI:10.22807/KJMP.2025.38.2.147 Vol.38(No.2) 147-156, 2025

유봉철 Bong Chul Yoo , 서정훈 Jung Hun Seo , 장재호 Jae Ho Jang

DOI:10.22807/KJMP.2025.38.2.157 Vol.38(No.2) 157-172, 2025

Limestone has been an essential resource for humans since ancient times and is currently utilized across various industries, including cement, iron and steel production, and chemical manufacturing. In 2023, it accounted for approximately 85% of South Korea’s domestic mineral production. Most limestone in South Korea is extracted from the Cambrian Pungchon Formation of the Paleozoic Joseon Supergroup, which is stratigraphically divided into a lower limestone, middle dolomite, and upper limestone. The upper limestone, being high-grade, constitutes the primary ore mined in these deposits. There are two prevailing hypotheses regarding the genesis of this high-grade limestone: (1) a syngenetic origin and (2) an epigenetic origin. Field mapping and drill core analysis of the Sungwoo limestone deposit yielded the following observations: 1) The limestone and hosting dolomite occur as banded layers, 2) The boundary between limestone and dolomite is irregular and cross-filling, 3) Relict dolomite is present within the limestone. Mineralogical analyses of these samples reveal the presence of ferroan dolomite, calcite, talc, Mg-rich chlorite, phengitic white mica, quartz, Kfeldspar, apatite, rutile, zircon, Cr-oxide, and Fe-oxide, indicating hydrothermal alteration. A reaction zone was microscopically observed at the interface between dolomite and calcite by using EPMA. There are significant variation of major element concentration (SiO₂, MgO, Al₂O₃, CaO, FeO and K₂O) across dolomite, the reaction zone, and calcite. The mineral assemblage―comprising dolomite, calcite, talc, chlorite, white mica, quartz, and K-feldspar―suggests formation under hydrothermal conditions at approximately 400℃ with low X_CO2. These findings suggest that the high-grade limestone in the Sungwoo deposit was formed epigenetically through reaction between pre-existing dolomite by a hydrothermal fluid.

중부 백운암, 석회석, 산상, 산출광물, 화학조성, Middle dolomite, Limestone, Occurrence, Mineral, Chemical composition