Chang Seong Kim

Skarn Evolution and Fe-(Cu) Mineralization at the Pocheon Deposit, Korea

The Pocheon skarn deposit, located at the northwestern part of the Precambrian Gyeonggi massif in South Korea, occurs at the contact between the Cretaceous Myeongseongsan granite and the Precambrian carbonate rocks, and is also controlled by N-S-trending shear zone. The skarn distribution and mineralogy reflects both structural and lithological controls. Three types of skarn formations based on mineral assemblages in the Pocheon skarn exist; a sodiccalcic skarn and a magnesian skarn mainly developed in the dolostone, and a calcic skarn developed in the limestone. Iron mineralization occurs in the sodic-calcic and magnesian skarn zone, locally superimposed by copper mineralization during retrograde skarn stage. The sodic-calcic skarn is composed of acmite, diopside, albite, garnet, magnetite, maghemite, anhydrite, apatite, and sphene. Retrograde alteration consists of tremolite, phlogopite, epidote, sericite, gypum, chlorite, quartz, calcite, and sulfides. Magnesian skarn mainly consists of diopside and forsterite. Pyroxene and olivine are mainly altered to tremolite, with minor phlogopite, talc, and serpentine. The calcic skarn during prograde stage mainly consists of garnet, pyroxene and wollastonite. Retrograde alteration consists of epidote, vesuvianite, amphibole, biotite, magnetite, chlorite, quartz, calcite, and sulfides. Microprobe analyses indicate that the majority of the Pocheon skarn minerals are enriched by Na-Mg composition and have high , , and ratios. Clinopyroxene is acmitic and diopsidic composition, whereas garnet is relatively grossular-rich. Amphiboles are largely of tremolite, pargasite, and magnesian hastingsite composition. The prograde anhydrous skarn assemblages formed at about in a highly oxidized environment (

Geology, Mineralogy and Geochemistry of the Shinyemi Iron Deposit, Korea: Implications for a Genetic Model

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Cretaceous epithermal gold–silver mineralization and geodynamic environment, Korea

The Shinyemi iron deposit, one of the biggest Fe deposits in South Korea, is proximal polymetallic deposits along the contact between the Cambro- Ordovician Makgol formation of the Joseon Supergroup and the Cretaceous granitoid. According to spatial location of the ore bodies, it can be divided by eastern Pb-Zn-Mo orebody and western Fe-Mo orebody. In recent boring data, these Shinyemi granitoid was intruded along gentle slope of Makgol carbonates and proximal iron orebody formed at both upper and lower part of the subvolcanic intrusives. The lower (eastern) orebody was transformed from the proximal Fe skarn at the bottom to a transitional Zn-CuMo skarn at the top. On the other hand, the upper (western) orebody exhibits predominant Fe-mineralization with brecciation. The aims of this study are to present and document characteristics of related igneous rocks and to discuss the evolution of skarn and ore formation model in the Shinyemi polymetallic mineralogical deposits.