• Journal of the Korean earth science society
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• v.28 no.6
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• pp.733-742
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• 2007

Petrological, mineralogical, and geochemical analyses were carried on the paleolithic obsidian implements excavated at Wolseongdong, Daegu, Korea. The obsidians has a homogeneous glassy texture that can be observed in a typical obsidian formed from a rapid cooling of silicic magma. Major element composition of the obsidians represent calc-alkaline series. Comparing those with other obsidians from domestic local excavation sites, Mt. Baekdu, and Kyusu of Japan, the Wolseongdong obsidians show similar element distribution pattern with others in spite of small difference in trace and rare Earth element contents. Sr isotopes of the obsidians considerably differ from those of the obsidians from southern part of the Korean Peninsula or from Mt. Baekdu. K-Ar age is approximately 30 Ma, which is much older than Mt. Baekdu (10 Ma). Therefore, considering the characteristics of obsidians found in the Korean Peninsula including mineralogy, petrology, trace element, and isotopes chronology, the obsidians can be divided into four groups: Mt. Baekdu, southern part of Korea (Kyusu of Japan), middle part of Korea, and Wolseongdong region. These groups suggest a possibility of more than four different origins of the obsidians found in the Korean Peninsular.

• Economic and Environmental Geology
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• v.49 no.5
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• pp.335-347
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• 2016

The mineralogical and geochemical characteristics of diverse carbonate rocks can be investigated by using VNIRSWIR(visible near infrared-short wavelength infrared) spectroscopic analysis as a rapid, nondestructive, and inexpensive tool. Comparing whole rock analysis to VNIR-SWIR spectroscopic analysis, the analytical method was investigated to estimate CaO contents, mud impurity, and whiteness of carbonate rocks involved in high-grade limestones in the field. We classify typical carbonate rocks in the upper Pungchon Formation in high-grade limestone mine area such as the Gangweon, Chungmu and Baegun mine in the Jeongseon area. The results show that powdered specimen has much higher reflectance than cutted specimen between the same sample. Whiteness is highly correlated with reflectance(0.99) for powdered specimen. The absorption of mineral mixtures shifts in position as a result of the mass ratio of calcite and dolomite in the Chungmu mine by changing to 75:25, 50:50, and 25:75. The absorption peak position in carbonate mixtures is highly correlated with CaO contents(0.98~0.99). Based on color system, the carbonate rocks are grouped into (milky) white, light grey, light brown, grey, and dark grey. The absorption peak position shifts from 2340 nm to 2320 nm as CaO contents decrease from 55.86 wt.% to 29.71 wt.%. We confirmed that absorption peak position shifts depending on the amount of Ca, which is bonded to $CO{_3}^{-2}$, Mg, and Fe contents replacing Ca. This result suggests that CaO contents in carbonate rocks can be considered to quantitative analysis in the field by spectroscopic analysis.

• 한국해양학회지
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• v.23 no.3
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• pp.110-122
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• 1988

Between the Clarion and Clipperton fracture zones of the Northeastern Pacific, nodules and crusts were collected from abyssal plain and hills by the Korea Ocean Research and Development Institute in December, 1983 aboard the R/V KANA KEOKI of the Hawaii Institute of Geophysics. Mineralogical and geochemical data of bulk nodules are obtained and compared with analyses of other studies. Mechanisms of nodule formation are discussed based on these data. Generally, the nodules of the KONOD-1 site are composed of todorokite and ${\delta}-MnO_2$. The contents of Mn, Fe, Ni, and Cu of the bulk nodules are variable and the average contents of metals are slightly lower (Mn, 21.40%; Ni, 0.9%; Cu, 0.8%) than those of nodules from other abyssal plains between the Clarion and Clipperton fracture zones. High Mn/Fe (average 3.9; maximum 5.9) and Cu/Ni (average 0.8; maximum 1.0) ratios are similar to the nodules that were formed diagenetically in the northeast Pacific. The chemical characteristics of the KONOD-1 nodules reflect their sedimentary environments; nodules with higher diagenetic signatures occur in areas of thin Quaternary siliceous ooze, and nodules of lower diagenetic influence occur in topographically irregular abyssal hill areas.

• The Journal of the Petrological Society of Korea
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• v.24 no.3
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• pp.193-207
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• 2015

This study analyzed ancient documents and established petrological database through extensive field investigation of provenance sites to presume stone source areas of the Seoul City Wall. By summarizing the ancient documents, the rampart stone was mostly supplied from a stony mountain adjacent to the City Wall in the early Joseon period, whereas the stone was provided from fixed quarry outside the City Wall in the late Joseon period. As a result of the petrological investigation based on quarries recorded in the ancient documents, pinkish granite and leucogranite were distributed as a whole, and the granitoid rocks are similar in mineralogical compositions and geochemical behavior characteristics. However, the pinkish granite with magnetic-series show that the magnetic susceptibility increased from the north slope of Namsan Mountain to Bulamsan Mountain. The leucogranite with ilmenite-series mainly occurred along the boundary between granite and gneiss from Yongmasan Mountain to Inwangsan Mountain. Consequently, the important petrological indicators for presumption of stone source areas are the rock color and the magnetic susceptibility. In addition to the petrological features, the reliability for provenance interpretation should improve considering stone quantities in the quarries, transportation distance and technical skills.

• Journal of the Korea Concrete Institute
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• v.24 no.3
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• pp.315-322
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• 2012

Alkali-activated slag (AAS) is the most obvious alternative materials that can replace OPC. But, AAS industrial usage as a structural material should be evaluated for its durability. Carbonation resistance is one of the most important factors in durability evaluation. Test results for 18 slag-based mortars activated by sodium silicate and 6 OPC mortars were obtained in this study to verify the carbonation property. Main variables considered in the study were flow, compressive strength before and after carbonation, and carbonation depth. Mineralogical and micro-structural analysis of OPC and AAS specimens prior to and after carbonation was conducted using XRD, TGA, FTIR FE-SEM. Test results showed that CHS was major hydration products of AAS and, unlike OPC, no other hydration products were found. After carbonation, CSH of hydration product in AAS turned into an amorphous silica gel, and alumina compounds was not detected. From the analysis of the results, it was estimated that the micro-structures of CSH in AAS easily collapsed during carbonation. Also, the results showed that this collapse of chemical chain of CSH lowered the compressive strength of concrete after carbonation. By increasing the dosage of activators, carbonation resistance and compressive strength were effectively improved.

• Resources Recycling
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• v.22 no.6
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• pp.64-72
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• 2013

The purpose of this study is to confirm the possibility of obtaining high grade coal from 57.39% of fixed carbon fine coal. Also, the mineralogical, physical/chemical and liberation characteristics are to be identified to decrease in ash amount, during the pre-processing of clean coal technology. In this study, batch flotation and CPT column flotation proper for the processing of fine particles were used with the variation in kinds and quantity of frother, collector and depressant. Also air flow rate and feeding rates were examined. As a result of batch flotation using 20% of pulp density DMU 101 collector(100 mL/ton), AF65 frother(300 mL/ton), sodium metaphosphate depressant (1 kg/ton), 67.57% of ash rejection and 70.90% of combustible recovery were obtained. The result of CPT column flotation was 85.59% of ash rejection and 88.97% of combustible recovery under the conditions of 5% of pulp density, DMU-101 collector (100 mL/ton), AF65 frother(10 L/ton), SMP depressant(1 kg/ton), wash water(100 mL/min.) and air flow rate(1,200 mL/min.).

• Economic and Environmental Geology
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• v.52 no.5
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• pp.449-457
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• 2019

We present the K-Ar age-dating results of the bulk and the less than $0.1{\mu}m$ fraction of the fault gouges collected from some major faults in the Gyeongsang basin. We try to determine the timings of fault activation based on the mineralogical characteristics, and to interpret the spatio-temporal variability of the major fault events during the Cenozoic Era by considering together with the previous results. We propose at least the 3-times of major fault events at about 50 Ma, and just after 30 Ma and 20 Ma in the Gyeongsang basin, which were inferred from the combined approach of the K-Ar ages and the clay mineralogy of the bulk fault gouges and the <$0.1{\mu}m$ fractions. The fault activation timings of the Yangsan fault tend to be younger in the northern part than in the southern part. In particular, the inferred fault events just after 30 Ma and 20 Ma are mainly detected in the Ocheon fault and the related faults, and the fault in the Gyeongju area. The fault activation timings of the major faults can be revised accurately by using illite-age-analysis(IAA) method. These geochronological determinations of the multiple events of the major faults in the Gyeongsang basin are crucial to establish the tectonic evolution in the southeastern part of the Korean Peninsula during the Cenozoic Era.

• Korean Journal of Soil Science and Fertilizer
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• v.19 no.3
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• pp.205-210
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• 1986

A soil micromorphological study of clayey terrace soils in Yeongnam area was carried out to investigate the soil genetic features and to distinguish the soil parent materials. Dominant plasmic fabrics in the terrace soils were vosepic, mosepic, insepic, and masepic of sepic fabrics but the Geugrag and Upyeong in Yeongil sequence have an asepic fabrics. Embedded grain cutans in the terrace soils were characterized by having porphyroskelic related distribution. Among pedological features of the B horizons of the terrace soils, the argillic cutans of ferriargillans and glaebules of manganiferrous concretions were the dominant in mineralogical composition, and the papules are abundant in the most terrace soils indicating that the soils are generally old. The substrata of the Bancheon in Yeongcheon and Upyeong in Yeongil area were so different from the terrace deposits in plasmic fabrics that these soils were believed to be composed of bisequum profiles. Because of having the free grain cutans, it was considered that the substrata of Bancheon in Yeongcheon and Upyeong in Yeongil area might have a period of soil formation before deposition of the terrace materials.

• Korean Journal of Soil Science and Fertilizer
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• v.32 no.4
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• pp.446-451
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• 1999

This study was carried out to investigate some mineralogical characteristics of Artificial Granular Zeolite (AGZ) and effect of AGZ on purification and alleviation of rice seedling damages of mine wastewater containing heavy metals. AGZ had mainly representative Na-P1 peaks and some $C_3S$ peaks of Portland cement in X-ray diffractogram. Differential thermal analysis represented that AGZ had weak endothermic peak around $130^{\circ}C$ and new deep endothermic peak around $750^{\circ}C$ as compared to powdery artificial zeolite. The ranking of heavy metals removals by AGZ, was lead> copper> cadmium> zinc in the synthetic wastewater. Root growth of rice seedling was greatly inhibited in the mine wastewater, and died after all. As AGZ treated into the mine wastewater with the ratio 1 : 50 (W : V) for one day or 1 : 100 for 4 days, the concentrations of heavy metals in the mine wastewater were decreased to below the critical concentration for agricultural use. And rice seedlings were grew with little damages in the purified water by AGZ.

• Korean Journal of Mineralogy and Petrology
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• v.33 no.4
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• pp.419-426
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• 2020

Understanding the pore structure including pore shape and connectivity in unconventional reservoirs is essential to increase the recovery rate of unconventional energy resources such as shale gas and oil. In this study, we found analysis condition to probe the nanoscale pore structure in shale reservoirs using Focused Ion Beam (FIB) and Ion Milling System (IMS). A-068 core samples from Liard Basin are used to probe the pore structure in shale reservoirs. The pore structure is analyzed with different pretreatment methods and analysis condition because each sample has different characteristics. The results show that surface milling by FIB is effective to obtain pore images of several micrometers local area while milling a large-area by IMS is efficient to observe various pore structure in a short time. Especially, it was confirmed that the pore structure of rocks with high content of carbonate minerals and high strength can be observed with milling by IMS. In this study, the analysis condition and process for observing the pore structure in the shale reservoirs is established. Further studies are needed to perform for probing the effect of pore size and shape on the enhancement of shale gas recovery.