• Economic and Environmental Geology
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• v.29 no.3
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• pp.281-291
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• 1996

Samples of Badwater greenstones from the Crystal Falls terrane in northeastern Wisconsin have been analyzed for major, trace and rare earth elements. Geochemical characteristics of the rocks provide clues to the petrologic character and paleotectonic environment of basaltic magma generation. They have chemical composition typical of continental tholeiites. The low Mg values and abundances of Ni and Cr indicate that the lavas were extensively fractionated prior to extrusion. The variations of incompatible elements suggest that the rocks were affected by interaction with crustal rocks. The samples least affected by contamination have trace element compositions similar to those of T-type mid-ocean ridge basalts. The parent was modified by crustal contamination process and this process shifted the rock compositions to that of continental tholeiites as the rock evolved. Interpretations of the chemical characteristics of the rocks, based on modem analogs, favor their emplacement in an extensional tectonic regime.

• Economic and Environmental Geology
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• v.50 no.6
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• pp.545-554
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• 2017

Birnessite is one of the dominant Mn (oxyhydr)oxide phases commonly found in soil and deep ocean environments. It typically occurs as nano-sized and poorly crystalline aggregates in the natural environment. It is well known that birnessite participates in a wide variety of bio/geochemical reactions as a reactive mineral phase with structural defects, cation vacancies, and mixed valences of structural Mn. These various bio/geochemical reactions control not only the fate and transport of inorganic and organic substances in the environment, but also the formation of diverse Mn (oxyhydr)oxides through birnessite transformation. This review assessed and discussed about the phase transformation of birnessite under a wide range of environmental conditions and about the potential geochemical factors controlling the corresponding reactions in the literature. Birnessite transformation to other types of Mn (oxyhydr)oxides were affected by dissolved Mn(II), dissolved oxygen, solution pH, and co-existing cation (i.e., $Mg^{2+}$). However, there still have been many issues to be unraveled on the complex bio/geochemical processes involved in the phase transformation of birnessite. Future work on the detail mechanisms of birnessite transformation should be further investigated.

• 한국석유지질학회:학술대회논문집
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• autumn
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• pp.56-62
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• 2001

울릉분지 남서부 해역에서 채취한 두 개의 피스톤 코어 (piston core) 시료를 이용하여 퇴적학 및 지화학적 특성을 연구하였다. 코어는 제4기말의 이질 퇴적물로 대부분 구성되어 있고, 테프라 (tephra layer)와 사질 퇴적물이 일부 협재되어 나타난다. 기존 확인된 울릉분지의 테프라를 이용하여 층서 대비를 한 결과, 두 코어는 대양보다는 높은 퇴적률 (10-12cm/kyr)을 갖는다. 이는 코어가 약 4만 4천년 전의 기록부터 시작하고 있음을 의미한다. 동위원소 층서 2 (마지막 빙기) 중에 형성된 구간에서는 저탁류의 영향을 많이 받은 여러 종류의 퇴적상들이 교호하여 나타난다. 코어의 하부 구간에서는 가스의 방출에 의하여 형성된 것으로 사료되는 수평균열이 다수 관찰된다. 두 코어에서 측정된 유기탄소 (organic carbon) 함량은 평균 $1.8\% $(0.1-4.5\%)$으로 열린 바다 (open sea) 퇴적물의 유기탄소 함량보다 높다. 이는 Termination I 시기 때 해수면 상승으로 인해 산소가 다소 결핍된 환경으로 전이되면서 유기탄소의 양이 증가하였음을 보여주는 것으로 해석된다.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 1998.11a
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• pp.114-118
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• 1998

농촌지역인 공주시 유구읍 명곡리 지역의 천부지하수와 먹는 샘물 공장의 취수정 심부 지하수을 대상으로 지화학적 특성을 밝히고, 물-암석 상호반응과 오염물질 유입에 대해서 토의하였다. 천부 지하수의 화학적 유형은 Ca-HCO$_3$형에서 Ca-Cl(SO$_4$)형으로 전반적으로 약산성화 되어있고, $K^{＋}$, Cl$^{-}$, NO$_3$$^{-}$오염이 상당히 진행되어 70 %이상이 음용수로 불가능한 상태이다. 군집방법에 의하면 신선한 물과 오염된 물사이에 뚜렷한 경향의 차이를 보인다. 천부지하수의 주요 오염원은 각가정에 있는 재래식 화장식, 생활하수, 가축의 축사, 비료등으로 보인다. 심부지하수는 알카리성의 Na-HCO$_3$형에서 Na(Ca)-HCO$_3$형의 화학적 유형이며, 2 TU 이하의 삼중수소 함량으로 1950년대 이전에 함양된 비교적 오랜 물-암석 상호반을 거친 물로 판단된다. 반면 천부형 지하수는 1950년대 이후에 충전된 상당히 젊은 연령의 지하수로 보인다. $^{18}$ O/$^{16}$ O, D/H 환경동위원소 조성값으로 볼 때 심부지하수의 함양지역은 고도의 효과를 보인다. 이 연구결과는 농촌지역의 지하수 수질 오염에 대한 하나의 사례연구로 향후 전국을 대상으로 한 농어촌지역의 지하수 오염연구에 기본방향을 제시하는데 의의 가 있을 것이다.

• Journal of the Korean Society for Marine Environment & Energy
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• v.4 no.3
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• pp.16-27
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• 2001

We have studied the phosphorus geochemistry in sediments from anoxic environments of Lake Shihwa. The dominant sedimentary phosphorus forms were detrital apatite P and Al-bound p, whereas the amount of Fe-bound P was low because of anoxic condition. Based on the correlation between TP(Total Phosphorus) and OC(Organic Carbon), the behavior of sedimentary phosphorus was influenced by organic matters. It shows that dissolved and solid phosphorus concentrations, the flux of phosphate and the correlation coefficients between sedimentary phosphorus and organic matter In St. Cl were higher than those in St. C2. The results indicate that the concentrations and distributions of phosphorus In sediments were controlled by organic matters.

• Economic and Environmental Geology
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• v.37 no.1
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• pp.1-19
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• 2004

Metallic deposits in Korea have a variety of genetic types such as hydrothermal veins, skarns, hydrothermal replacement and alaskite deposits and so on. Geological, mineralogical and geochemical features including host rock, wall-rock alteration, ore and gangue mineralogy, mineral texture and secondary mineralogy related to weathering process control the environmental signatures of mining areas. The environmental signatures of metallic deposits closed from early 1970s to late 1990s in Korea show complicate geochemistry and mineralogy due to step weathering of primary and secondary minerals such as oxidation-precipitation-remobilization. The potentiality of low pH and high heavy metal Concentration s from acid mine drainage is great in base-metal deposits associated with polymetallic mineralization, breccia-pipe type and Cretaceous hydrothermal Au veins with the amount of pyrite whereas skam, hydrothermal replacement, hydrothermal Cu and Au-Ag vein deposits are in low contamination possibility. The geoenvironmental models reflecting the various geologic features closely relate to disuibution of sulfides and carbonates and their ratios and finally effect on characteristics of environmental signatures such as heavy metal species and their concentrations in acid mine drainage.

• The Journal of Engineering Geology
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• v.24 no.4
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• pp.535-550
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• 2014

The origins and varieties of natural radioactive materials, including uranium and radon-222, were examined in a drilled borehole extending to a depth of 120 m below the surface in the Goesan area. In addition to core samples, eight groundwater samples were collected at different depths, using a double packer system and bailer, and their geochemical characteristics were determined. Most of the rock samples from the drilled core consisted of granite porphyry, with sedimentary rocks (slate, carbonate, or lime-silicates) and pegmatite occurring in certain sections. The pH of samples varied from 7.8 to 8.4, and the groundwater was of a Na-$HCO_3$type. Uranium and thorium concentrations in the core were < 0.2-14.8 ppm and 0.56-45.0 ppm, respectively. Observations by microscope and an electron probe microanalyzer (EPMA) showed that the mineral containing the natural radioactive materials was monazite contained in biotite crystals. The uranium, which substituted for major elements in the monazite, appeared to have dissolved and been released into the groundwater in a shear zone. Concentrations of Radon-222 in the borehole showed no close relationship with levels of uranium. The isotopes of noble gases, such as helium and neon, would be useful for analyzing the origins and characteristics of the natural radioactive materials.

• Economic and Environmental Geology
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• v.43 no.5
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• pp.477-490
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• 2010

The Gagok stratabound skarn deposit is the result of the intrusion of the Cretaceous granitic pluton into the Paleozoic calcareous rocks. The subvolcanic intrusion ranges in composition from quartz monzonite to granite porphyry with I-type, calc-alkaline and weakly peraluminous characteristics. Both endoskarn and exoskarn are developed at the Gagok Zn-(Pb) deposit, with more exoskarn than endoskarn. Geochemical and mineralogical characteristics in the Seongok and Wolgok orebodies can be treated in terms of self-organization. Sphalerites in the Gagok ore can also incorporate minor amounts of Mn, Cd, Cu and In. Trace element concentrations in different orebodies vary because fractionation of a given element into sphalerite is influenced by formation temperature and the amount of sphalerite in the ore. A group of high In/Zn and Cd/Zn ratios in ores, and low Mn/Fe ratios in sphalerites are correlated with proximal processes of a magmatic source. The pattern of minor/trace element variations in ores and sphalcrites can be used for petrogenetic interprctation, e.g., orebody zonation related to crystallization temperature and fluid d sources.

• Economic and Environmental Geology
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• v.41 no.2
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• pp.183-199
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• 2008

This study is focused on characterization of the physio-chemical and mineralogical properties, investigation of their vertical changes in the tailing profile of the Guryoung mining area, classification of the profile into distinct zones, and condition conceptual model of physio-chemical conditions and phases-water relationships controlling the element behaviors in the tailings. The upper part of the groundwater is characterized by the high contents of $Fe_2O_3$ and $SO_3$ for whole rock analysis, low pH, and the occurrence of jarosite, schwertmannite and Fe-oxyhydroxide as the secondary mineral phases. The tailing profile can be divided into the covering soil, jarosite zone, Fe-sulfate zone, Fe-oxyhydroxide and gypsum-bearing pyrite zone, calcite-bearing pyrite zone, soil zone, and weathered zone on the based of the geochemical and mineralogical characteristics. The profile can be sampled into the oxidized zone and the carbonate-rich primary zone with the dramatic changes in pH and the secondary mineral phases. The conceptual model proposed for the tailing profile can be summarized that the oxidation of pyrite is the most important reaction controlling the changes in pH, the dissolution of the primary silicates and carbonates, the precipitation of secondary mineral phases, acid-neutralizing, and heavy metal behaviors through the profile.

• Journal of the Korean earth science society
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• v.34 no.4
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• pp.313-328
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• 2013

Jurassic granitoids in the northeastern part of the Yeongnam Massif are possibly the result of intensive magmatic activities that occurred in response to subduction of the proto-Pacific plate beneath the northeast portion of the Eurasian plate. Geochemical studies on the granitic rocks are carried out in order to constrain the petrogenesis of the granitic magma and to establish the paleotectonic environment of the area. Whole rock chemical data of the Uljin granitoids in the northeastern part of the Yeongnam Massif indicate that all of the rocks have the characteristics of calcalkaline series in subalkaline field. The overall major element trends show systematic variations in each granitic body, but the source materials of each granitoids seem to have different chemical composition. The Uljin granitoids are different from other granitic rocks, which distributed vicinity of the study area, in the contents of $Al_2O_3$ and trace elements such as Cr, Co, Ni, Sr, Y and Nb. The Uljin granitoids have geochemical features similar to slab-derived adakites such as high $Al_2O_3$, Sr contents and high Sr/Y, La/Yb ratios, but they have low Y and Yb contents. The major ($SiO_2$, $Al_2O_3$, MgO) and trace element (Sr, Y, La, Yb) contents of the Uljin granitoids fall well within the adakitic field. The Uljin granitoids have similar geochemical characteristics, paleotectonic environments and intrusion ages to those of the Yatsuo plutonic rocks of Hida belt located on northwestern part of Japan. Chondrite normalized REE patterns show generally enriched LREEs ($(La/Yb)_{CN}=10.6-103.4$) and are slight negative to flat Eu anomalies. On the ANK vs. A/CNK and tectonic discrimination diagrams, parental magma type of the granites corresponds to I-type and volcanic arc granite (VAG). Interpretations of the chemical characteristics of the granitic rocks favor their emplacement in a compressional tectonic regime at the continental margin during the subduction of Izanagi plate in Jurassic period.