• Journal of Conservation Science
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• v.33 no.1
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• pp.25-33
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• 2017

The stone lantern of the four guardian kings in the Beopjusa temple at Boeun was mainly made of biotite granodiorite consisting of porphyritic-textured potassium feldspar and included in ilmenite series. A base stone made of alkali granite was buried, after founded its place during an earlier restoration process. Cracking and break out are noticeable on this object. In addition, discoloration, salt crusting, and epiphytes were observed. The lantern was vulnerable in terms of physical and structural stability caused by cracking in the front and back of the light chamber and in the non-horizontal direction. According to the conservational condition of the stone lantern, structural reinforcement was carried out based on calculations, including those on the position, size, and anchor length of the titanium stiffener. Chemical and biological pollutants were washed off without damage to the surface of the stone material. Oxygenated iron pieces were replaced with titanium. Ethyl silicate was applied to the surface of the lantern for consolidation and smooth drainage.

• Journal of the Mineralogical Society of Korea
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• v.23 no.4
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• pp.413-428
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• 2010

The Gukjeon Pb-Zn mine was recognized as skarn deposits which replaced the limestone layer of the Jeongkansan Formation by intrusion of biotite granite in late Cretaceous. The Jeongkansan Formation is mainly composed of tuffaceous shale, and interlayers of sandstone, andesitic tuff, limestone, and conglomerate. The limestone layer is located in the lower part of the Jeongkansan Formation with 6~8 m in thickness and about 500 m in length. The Gukjeon deposits are divided into the Jukgang ore bodies once mined underground and the eastern ore bodies. Main ores are sphalerite and galena, in association with small amounts of chalcopyrite, arsenopyrite, pyrite, and pyrrhotite, etc. Skarns mainly consist of clinopyroxenes and Ca-garnets, associated with actinolite, chlorite, axinite, and calcite, etc. The Jukgang ore bodies show symmetrical distribution of zoning outward, representing clinopyroxene (hedenbergite) zone, clinopyroxene-garnet (grossular) zone, garnet (andradite) zone, and alteration zone of hornfels. $Fe^{2+}$ contents in clinopyroxenes increase with decreasing sphalerite grade. Sphalerite ores are found in all zones and $Fe^{2+}$ contents in sphalerite increase in the same way as those in clinopyroxenes, implying that clinopyroxene and sphalerite are closely related each other. It is concluded that the Gukjeon ores occurred in the ore rich zone of high grade sphalerite with less pyrite in assoication with clinopyroxene.

• Korean Journal of Heritage: History & Science
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• v.48 no.4
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• pp.62-73
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• 2015

The Tae-Jo Geonwolleung is the tomb of the first king Tae-Jo of the Joseon Dynasty in the complex of the Royal Tombs of the Joseon Dynasty which is listed in World Heritage, and it contains various types of stone properties. The material of the stone properties consist of a single type of medium-grained biotite granite, however, each properties have different intensity and types in deterioration phenomena according to their locations and purposes. The major deterioration types of the stones are analyzed as physical decomposition and biodeterioration. The exfoliation, breaking-out and granular decomposition are widespread types of the deterioration throughout the entire burial mound stone properties and surrounding stone properties. On the other hands, the colonization of mosses and plants, and contamination by foreign materials are found more frequent in the burial mound stone properties as these stones are in contact with the soil of the tomb mound and moisture in the soil helped biodeterioration. It is suggested that anti-biology treatment and physical reinforcement are applied to the deteriorated stones to prevent further damage on the stone components of the tomb.

• Journal of Conservation Science
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• v.37 no.6
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• pp.778-790
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• 2021

The Stone Seated Buddha Triad and Stone Standing Buddha in Bijung-ri are state-designated heritage (treasure) statues having the Buddha style of the Goryeo dynasty from the 6th century. Conservation scientific investigations were conducted to understand the preservation status of these stone Buddha statues and to establish a conservation plan. The Stone Seated Buddha Triad and Stone Standing Buddha are composed of fine-medium grained biotite granite, which is considered to be of the same origin owing to their low magnetic susceptibility distribution of less than 0.2 (×10^-3 SI unit) and similar mineral characteristics. The Stone Seated Buddha Triad has highly homogenous mineral composition and particle size, whole-rock magnetic susceptibility, and geochemical characteristics very similar to those of the nearby outcrop. It was confirmed that a combination of physical, chemical, and biological factors affects the Stone Buddha statues. In particular, both the Stone Seated Buddha Triad and Stone Standing Buddha tend to be chipped off from the front and cracked and scaled from the back. The Stone Standing Buddha located outdoors experiences granularity decomposition and black algae formation, which accelerate the weathering under unfavorable conservation environments. The result of non-destructive physical property diagnosis using ultrasonic velocity showed that both the Stone Seated Buddha Triad and Stone Standing Buddha have been completely weathered (CW), indicating very poor physical properties.

• Economic and Environmental Geology
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• v.51 no.5
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• pp.409-428
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• 2018

Yeongdong area is located on the border zone between Precambrian Yeongnam massif and central southeastern Ogcheon metamorphic belt, in which Cretaceous Yeongdong sedimentary basin exists. Main geology in this area consists of Precambrian Sobaeksan gneiss complex, Mesozoic igneous and sedimentary rocks and Quaternary alluvial deposits. Above this, age-unknown Ogcheon Supergroup, Paleozoic sedimentary rocks and Tertiary granites also occur in small scale in the northwestern part. This study focuses on the link between the various geology and Rn concentrations in groundwater. For this, twenty wells in alluvial/weathered zone and sixty bedrock aquifer wells were used. Groundwater sampling campaigns were twice run at wet season in August 2015 and dry season in March 2016. Some wells placed in alluvial/weathered part of Precambrian metamorphic rocks and Jurassic granite terrains, as well as Cretaceous porphyry, showed elevated Rn concentrations in groundwater. However, detailed geology showed the distinct feature that these high-Rn groundwaters in metamorphic and granitic terrains are definitely related to proximity of aquifer rocks to Cretaceous porphyry in the study area. The deeper wells placed in bedrock aquifer showed that almost the whole groundwaters in biotite gneiss and schist of Sobaeksan gneiss complex and in Cretaceous sedimentary rocks of Yeongdong basin have low level of Rn concentrations. On the other hand, groundwaters occurring in rock types of granitic gneiss or granite gneiss among Sobaeksan gneiss complex have relatively high Rn concentrations. And also, groundwaters occurring in the border zone between Triassic Cheongsan granites and two-mica granites, and in Jurassic granites neighboring Cretaceous porphyry have relatively high Rn concentrations. Therefore, to get probable and meaningful results for the link between Rn concentrations in groundwater and surrounding geology, quite detailed geology including small-scaled dykes or vein zones should be considered. Furthermore, it is necessary to take account of the spatial proximity of well location to igneous rocks associated with some mineralization/hydrothermal alteration zone rather than in-situ geology itself.

• Journal of the Mineralogical Society of Korea
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• v.17 no.1
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• pp.61-73
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• 2004

The purposes of this study are to investigate the occurrence, the hydrochemical characteristics and the origin of the $CO_2$-rich springs from the Kangwon Province, and to reanalyze the previous studied results of other researchers. The $CO_2$-rich water samples were collected at 13 locations in the Kangwon Province. The $CO_2$-rich water shows a high $CO_2$ concentration ($P_{CO2}$ 0.787 to 4.78 atm), weak acidic pHs, electrical conductivity values ranging from 422 to 2,280 $\mu$S/cm, and high Fe and F contents. The chemical compositions of $CO_2$-rich water from this study area are classified into three types; $Ca-HCO_3$, Ca(Na)-$HCO_3$, $Na-HCO_3$ types. The chemical data of $CO_2$-rich waters and their host rocks indicate that $Na-HCO_3$ type water are mainly influenced by biotite, K-feldspar granite, and Ca(Na)-HC $O_3$, type water is chiefly influenced by gneiss and carbonate minerals in granite. F and Fe contents of $CO_2$-rich waters are abundant in $Na-HCO_3$, and $Ca-HCO_3$ types, respectively. The results of this study suggest that the chemical composition $CO_2$-rich water is mainly controlled by the mineralogical composition of aquifer host rocks. Oxygen and deuterium isotope data indicate that $CO_2$-rich water is meteoric origin. The $\delta^{13}$C values (-0.3$\textperthousand$ to -6.2$\textperthousand$ PDB) suggest that dissolved carbonates are mainly derived from a deep-seated $CO_2$ and partly from carbonate minerals.

• The Journal of Engineering Geology
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• v.18 no.4
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• pp.555-566
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• 2008

Hydrogeochemical study in Samseung area (Boeun, Chungbuk) and waterrock interaction experiment using rock samples from the area were performed to elucidate the fluoride source in groundwater and explaining geochemical behavior of fluoride ion. Fluoride concentration of public water supply mostly using groundwater in Boeun area was significantly higher in South Korea. The maximum fluoride concentration of the study area was 3.9 mg/L, and 23% of samples exceeded the Korean Drinking Water Standard of fluoride (1.5 mg/L). The average concentration of fluoride was 1.0 mg/L and median was 0.5 mg/L. Because of high skewness (1.3), median value is more appropriate to represent fluoride level of this area. The relationships between fluoride ion and geochemical parameters ($Na^+$, $HCO_3$, pH, etc.) indicated that the degree of waterrock interaction was not significant. However, high fluoride samples were observed in $NaHCO_3$ type on Piper's diagram. The negative relationship between fluoride and $NO_3$ ion which might originate from surface contaminants was obvious. These results indicate that fluoride ion in groundwater is geogenic origin. The source of fluoride was proved by waterrock interaction batch test. Fluoride concentration increased up to 1.2 mg/L after 96 hours of reaction between water and biotite granite. However, the relationship between well depth and fluoride ion, and groundwater age and fluoride ion was not clear. This indicates that fluoride ion is not correlated with degree of waterrock interaction in this area but local heterogeneity of fluoriderich minerals in granite terrain. High fluoride concentration in Boeun area seems to be correlated with distribution of permeable structures in hard rocks such as lineaments and faults of this area. This entails that the deep bedrock groundwater discharges through the permeable structures and mixed with shallow groundwater.

• Korean Journal of Heritage: History & Science
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• v.55 no.4
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• pp.180-193
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• 2022

The East Nine Royal Tombs is a representative place in the Royal Tombs of Joseon (a World Heritage Site). It consists of 1,289 stone artifacts including 979 related stone structures, 310 stone statues, and objects. Most of the stone structures in the East Nine Royal Tombs are composed of biotite granite, but some tombs are composed of light red granite. As a result of magnetic susceptibility measurement, the average data from Geonwolleung to Mongneung, excluding Hyeolleung, were similar, so it is estimated that stones were obtained from the same quarry. In the case of Sungneung, Sureung, and Gyeongneung, the range of susceptibility measurement is widely distributed. It assumed that the newly produced stones were mixed in the moving and construction process. Also, stones might be gathered from different quarries. As a result of a conservation status investigation, both the mound member and the ridge stone had the highest damage rate due to peeling and granular decomposition according to surface weathering. In the case of surface discoloration, yellowing and soils were found in the burial mound members. Yellowing, blackening, and soil were identified in the ridge stone structures. Bio-degradation is the major factor of deterioration of the East Nine Royal Tombs and the conservation status of the tombs were detected as grades 4 to 5. It seems that it is easy for the environment of the royal tombs to form soil for the microorganisms and fine conditions for continuous moisture. In the case of structures, they are in relatively good condition. As a result of a comprehensive damage rating for each tomb, the overall condition is good, but the Geonwolleung Royal Tomb and Hyeolleung Tomb, which were created in the early period, had relatively high weathering ratings. Stone objects in East Nine Royal Tombs have lost many pieces and gateway members due to surface deterioration. Also, secondary damage is ongoing. Each damage factor of the stone artifacts of the East Nine Royal Tombs combines to cause various and continuous damages. Therefore, it is necessary to establish regular conservation status data of the stone artifacts for efficient management after processing as well as conservation treatment of the royal tombs, and specific management manuals and systems. This study investigated the conservation status of stone structures in the East Nine Royal Tombs, a World Heritage Site, and systematically classified them to provide priority and necessity for conservation processing. We look forward to establishing a plan for the conservation and management of the East Nine Royal Tombs with this database in the future.

• Economic and Environmental Geology
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• v.47 no.4
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• pp.335-349
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• 2014

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 $Fe^{3+}/Fe^{2+}$, $Mg^{2+}/Fe^{2+}$, and $Al^{3+}/Fe^{2+}$ 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 $400^{\circ}{\sim}500^{\circ}C$ in a highly oxidized environment ($fO_2=10^{-23}{\sim}10^{-26}$) under a condition of about 0.5 kbar pressure and $X(CO_2)=0.10$. With increasing fluid/rock interaction during retrograde skarn, epidote, amphibole, sulfides and calcite formed as temperature decreased to approximately $250^{\circ}{\sim}400^{\circ}C$ at $X(CO_2)=0.10$.

• Economic and Environmental Geology
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• v.34 no.5
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• pp.423-435
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• 2001

The gold-silver vein deposits in the Mugeug mineralized area are emplaced in late Cretaceous biotite granite associated with the pull-apart type Cretaceous Eumseong basin. Mugeug mine in northern part is composed of multiple veins showing relatively high gold fineness and is characterized by sericitization, chloritization and epidotization. The ore-forming fluids were evolved by dilution and cooling mechanisms at relatively high temperature and salinity (=30$0^{\circ}C$,1~9 equiv. wt. % NaCl) and highly-evolved meteoric water ($\delta$$^{18}$ O;-1.2~3.7$\textperthousand$) and gold mineralization associated with sulfides tormed at temperatures between 260 and 22$0^{\circ}C$ and within sulfur fugacity range of 10$^{-11.5}$ ~ 10$^{-13.5}$ atm. In contrast, Geumwang, Geumbong and Taegueg mines show the low fineness values, in southern part are characterized by increasing tendency of simple and/or stockwork veins and by kaolinitization, silicificatitan, carbonatization and smectitization. These droposits formed at relatively low temperature and salinity (<23$0^{\circ}C$, <3 equiv. wt. % NaCl) from ore-forming fluids containing greater amounts of less-evolved meteoric waters ($\delta$$^{18}$ O;-5.5~4.0$\textperthousand$), and silver mineralization representing various gold-and/or silver-bearing minerals formed at temperatures between 200 and 15$0^{\circ}C$ and from sulfur fugacity range of 10$^{-15}$ ~10$^{-18}$ atm These results imply that mineralization in the Mugueg area formed at shallow-crustal level and categorize these deposits as low-sulfidation epithermal type. The genetic differences between the northern and southern parts reflect the evolution of the hydrothermal system due to a different physicochemical environment from heat source area (Mugeug mine) to marginal area (Taegeum mine) in a geothermal field.