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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Economic and Environmental Geology
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The Korean Society of Economic and Environmental Geology
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Volume & Issues
Volume 49, Issue 4 - Aug 2016
Volume 49, Issue 3 - Jun 2016
Volume 49, Issue 2 - Apr 2016
Volume 49, Issue 1 - Feb 2016
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Characterization of Mineralogical Changes of Chrysotile and its Thermal Decomposition by Heat Treatment
Jeong, Hyeonyi ; Moon, Wonjin ; Roh, Yul ;
Economic and Environmental Geology, volume 49, issue 2, 2016, Pages 77~88
DOI : 10.9719/EEG.2016.49.2.77
Chrysotile is a 1:1 sheet silicate mineral belonging to serpentine group. It has been highlighted studies because of uses, shapes and structural characteristics of the fibrous chrysotile. However, it was designated as Class 1 carcinogen, so high attentions were being placed on detoxification studies of chrysotile. The objectives of this study were to investigate changes of mineralogical characteristics of chrysotile and to suggest detoxification mechanism of chrysotile by thermal decomposition. Samples for this study were obtained from LAB Chrysotile mine in Canada. The samples were heated in air in the range of 600 to
. Changes of mineralogical characteristics such as crystal structure, shape, and chemical composition of the chrysotile fibers were examined by TG-DTA, XRD, FT-IR, TEM-EDS and SEM-EDS analyses. As a result of thermal decomposition, the fibrous chrysotile having hollow tube structure was dehydroxylated at
and transformed to disordered chrysotile by removal of OH at the octahedral sheet (MgOH) (Dehydroxylation 1). Upon increasing temperature, it was transformed to forsterite (
by rearrangement of Mg, Si and O (Dehydroxylation 2). In addition, crystal structure of forsterite had begun to transform at
, and gradually grown 3-dimensionally to enstatite (
) by recrystallization after the heating above
. And then finally transformed to spherical minerals. This study showed chrysotile structure was collapsed about
by dehydroxylation. And then the fibrous chrysotile was transformed to forsterite and enstatite, as non-hazardous minerals. Therefore, this study indicates heat treatment can be used to detoxification of chrysotile.
Molybdenum Isotope Analysis of Standard Reference Materials
Jo, Yunsoo ; Kil, Youngwoo ; Ryu, Jongsik ; Seol, Junghwan ; Nguyen, The Cong ; Jung, Woochul ; Park, Sanghee ;
Economic and Environmental Geology, volume 49, issue 2, 2016, Pages 89~95
DOI : 10.9719/EEG.2016.49.2.89
Mo isotope, one of highly redox-sensitive isotopes, has been shown to be useful tracers of geochemical processes. Many studies for Mo isotope have documented with the help of recently developed analysis tools, but it has not yet been documented in the Korea. In this study, we introduce two-stage column separation method of Mo using column tube (BioRad PolyPrep(R) column, 10 ml) and anion exchange resin (BioRad Resin AG(R) 1-X8, 200-400 mesh). Mo isotope ratios in the solid SRMs (BHVO-2, SDO-1, PACS-2) and liquid SRM (IAPSO) were measured on MC-ICP-MS (Multi-collector Inductively Coupled Plasma Mass Spectrometer) and then compared with reference Mo isotope ratios. Mo isotope ratios in our study overlap with reference Mo isotope ratios within analytical error.
Reactivated Timings of Yangsan Fault in the Sangcheon-ri Area, Korea
Song, Yungoo ; Park, Changyun ; Sim, Ho ; Choi, Woohyun ; Son, Moon ; Khulganakhuu, Chuluunbaatar ;
Economic and Environmental Geology, volume 49, issue 2, 2016, Pages 97~104
DOI : 10.9719/EEG.2016.49.2.97
Here we firstly present that a timing of reactivated event of Yangsan fault, the major fault in the southeastern Korean Peninsula, by using combined approaches of the optimized illite-polytype quantification, the K-Ar age-dating, and the recently developed illite-age-analysis (IAA) approach for the fault clays from Sangcheon-ri area of Yangsan main fault line. Two chronological record of brittle fault-activation event at about 41.5~43.5 and 50.7 Ma were determined from 3 fault gouges suggesting a crucial reactivation time-scheme. Furthermore, the regional processes that drive tectonics to form and reactivate the Yangsan fault may be explained from the chronological analysis for additional sites along the Yangsan fault.
Groundwater-Stream Water Interaction Induced by Water Curtain Cultivation Activity in Sangdae-ri Area of Cheongju, Korea
Moon, Sang-Ho ; Kim, Yongcheol ; Jeong, Youn-Young ; Hwang, Jeong ;
Economic and Environmental Geology, volume 49, issue 2, 2016, Pages 105~120
DOI : 10.9719/EEG.2016.49.2.105
Most of riverside in Korea, in case of application of water curtain cultivation (WCC) technique, has been inveterately suffering from the gradual drawdown of groundwater level and related shortage of water resources during the WCC peak time. We believe that the water resources issue in these riverside areas can be effectively solved when the interaction between groundwater and nearby surface water is well understood. To investigate the connection between stream and ground water, and the influence of stream water on the nearby aquifer, this study examined the water temperature and oxygen and hydrogen stable isotopic compositions. The study area is well-known strawberry field applying the WCC technique in Sangdae-ri, Gadeok-myon, Cheongju City, and the sampling was done from February 2012 through June 2014 for stream and ground water. Some groundwater wells near stream showed big temporal variations in water temperature, and their oxygen and hydrogen stable isotopes showed similar compositions to those of adjacent stream water. This indicates that the influence of stream water is highly reflected in the stable isotopic composition of groundwater. Four cross-sectional lines from stream to hillside were established in the study area to determine the spatial differences in water quality of wells. At the late stage of WCC in February to March, groundwater of wells in line with short cross-sectional length showed the narrow range of isotopic compositions; however, those in the long cross-sectional line showed a wide compositional range. It was shown that the influence of the stream water at the late WCC stage have reached to the distance of 160 to 165 m from stream line, which is equivalent to the whole length and one-third point in each short and long cross-sectional line, respectively. Therefore, the wide compositional range in the long cross-sectional lines was not only due to the influence of stream water, but apparently resulted from the change of relative impact of each groundwater supplying from two or more aquifers. In view of stable isotopic compositions, there seems to be three different aquifers in this study area, which is competing for dominance of water quality in wells at each period of WCC.
Characterizing Geomorphological Properties of Western Pacific Seamounts for Cobalt-rich Ferromanganese Crust Resource Assessment
Joo, Jongmin ; Kim, Jonguk ; Ko, Youngtak ; Kim, Seung-Sep ; Son, Juwon ; Pak, Sang Joon ; Ham, Dong-Jin ; Son, Seung Kyu ;
Economic and Environmental Geology, volume 49, issue 2, 2016, Pages 121~134
DOI : 10.9719/EEG.2016.49.2.121
We characterize the spatial distribution of Cobalt-rich ferromanganese crusts covering the summit and slopes of a seamount in the western Pacific, using acoustic backscatter from multibeam echo sounders (MBES) and seafloor video observation. Based on multibeam bathymetric data, we identify that ~70% of the summit area of this flattopped seamount has slope gradients less than
. The histogram of the backscatter intensity data shows a bi-modal distribution, indicating significant variations in seabed hardness. On the one hand, visual inspection of the seafloor using deep-sea camera data exhibits that the steep slope areas with high backscatter are mainly covered by manganese crusts. On the other hand, the visual analyses for the summit reveal that the summit areas with relatively low backscatter are covered by sediments. The other summit areas, however, exhibit high acoustic reflectivity due to coexistence of manganese crusts and sediments. Comparison between seafloor video images and acoustic backscatter intensity suggests that the central summit has relatively flat topography and low backscatter intensity resulting from unconsolidated sediments. In addition, the rim of the summit and the slopes are of high acoustic reflectivity because of manganese crusts and/or bedrock outcrops with little sediments. Therefore, we find a strong correlation between the acoustic backscatter data acquired from sea-surface multibeam survey and the spatial distribution of sediments and manganese crusts. We propose that analyzing acoustic backscatter can be one of practical methods to select optimal minable areas of the ferromanganese crusts from seamounts for future mining.
Pb and Zn in Peru: Supply Trend and Resource Amounts
Ale, Jorge Acosta ; Santisteban, Alexander ; Huanacuni, Dina ; Yang, Seok-Jun ; Heo, Chul-Ho ;
Economic and Environmental Geology, volume 49, issue 2, 2016, Pages 135~145
DOI : 10.9719/EEG.2016.49.2.135
Until 2014, 14 million tonnes of Pb (metal based) and 41 million tonnes of Zn (metal based) were produced in Peru. Representative two Pb-Zn metallogenic belts were known in Peru. They are lower Cretaceous-Paleocene VMS Cu-Zn-Au metallogenic belt and Miocene epithermal, skarn, replacement & polymetallic vein metallogenic belt. If four new mining projects were launched and additional three mining projects were prepared until 2017, it seems possible to produce 0.34 million tonnes of Pb and 1.5 million tonnes of Zn additionally. In Pb-Zn metallogenic belt in Peru, potential Zn amounts range from 9 to 6000 million tonnes with 0.1 to 14% Zn and potential Pb amounts range from 5 to 2800 million tonnes with 0.04 to 5.3% Pb.
SHRIMP U-Pb Age of the Early Jurassic Deformed Granites in the Aneui Quadrangle, SW Yeongnam Massif
Seo, Jaehyeon ; Song, Yong-Sun ; Park, Kye-Hun ;
Economic and Environmental Geology, volume 49, issue 2, 2016, Pages 147~153
DOI : 10.9719/EEG.2016.49.2.147
SHRIMP U-Pb age determination was carried out for deformed granites in the Aneui quadrangle, SW Yeongnam Massif. Dating of zircons from a highly deformed mylonitic granite with banded structure and a relatively less deformed porphyritic to augenic granites, that were known as Precambrian gneisses, yielded the same age of ca. 195 Ma. On the basis of this result and previous age data, Early to Middle Mesozoic igneous activity around the Aneui area was interpreted as follows; Subduction-related granitic magmatism started with the intrusion of the Hamyang Granite in the middle Triassic (ca. 225-219 Ma) mainly in the west of the area and ended with syenitic intrusion at the end of Triassic period (ca, 220-210 Ma). After a relatively short period of quiescency, granitic magmatism restarted with the intrusion of magma forming deformed granites dated in this study at the Early Jurassic of ca. 195 Ma and continued to ca. 189 Ma and dioritic intrusion was associated around the late stage of granitic magmatism.
Geologic Age of Quartz Schist - Quartzite from Yeongam and Yeongsanpo Areas around Southwestern Part of Ogcheon Belt
Choi, Sung-Ja ; Kim, Dong-Yeon ; Song, Kyo-Young ;
Economic and Environmental Geology, volume 49, issue 2, 2016, Pages 155~165
DOI : 10.9719/EEG.2016.49.2.155
Quartz schist - quartzite is often intercalated in metasedimentary rocks of Ogcheon belt or aligned parallel to the boundary between Yeongnam massif and Ogcheon belt. However, stratigraphic sequence and or geologic age of the rocks has been still variable among authors as Precambrian or Paleozoic. In this study, we carried out SHRIMP U-Pb age data of detrital zircons from Yeongam and Yeongsanpo areas and compared ours with other zircon ages from other areas. The detrital zircons from the studied area show no age younger than 1.8 Ga but yielded clusters at Neoarchean (2.5 Ga) and Paleoproterozoic (1.8 Ga). On the other hand, the age range of zircon U-Pb dating of Paleozoic quartzites yielded from Archean to middle Paleozoic and clusters at Paleoproterozoic, Neoproterozoic and Paleozoic. The characteristics of the zircon age range and the dominant age peak might become a key to classify the Proterozoic to Paleozoic quartz schists-quartzites, which ages are still remained under controversy. Based on the statistical results of the zircon ages in this study, quartz schist - quartzite from Yeongam and Yeongsanpo is considered to be deposited during Proterozoic.