• 한국석유지질학회:학술대회논문집
• /
• spring
• /
• pp.24-24
• /
• 2004

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
• /
• 2000.05a
• /
• pp.158-158
• /
• 2000

• Proceedings of the KSEEG Conference
• /
• 1999.04a
• /
• pp.8-10
• /
• 1999

• The Journal of the Petrological Society of Korea
• /
• v.12 no.2
• /
• pp.55-69
• /
• 2003

A spinifex textured komatiite sample of Early Tertiary age, from the Gorgona Islands of Colombia in South America, was petrographically and geochemically studied, and compared with the previous researches of the komatiites including other Precambrian komatiites in South Africa, Western Australia and Canada. The sample shows the komatiitic characteristics in its petrography and geochemistry very well, i.e. in high specific gravity (2.98) and density (3.2), rock forming minerals, spinifex texture, major and race element abundances and REE pattern. In particular the REE pattern for it strongly suggests that the Gorgona komatiite must have been crystallized from a magma generated from a depleted mantle as that of Munro Township area in Ontario, Canada which is pyroxenite komatiite or basaltic komatiite of Group I of the Archean.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
• /
• 2002.09a
• /
• pp.335-338
• /
• 2002

방사성폐기물처분연구의 일환으로 화강암지역내 심부지하수에 대한 지화학특성조사가 수행되었다. 지하수 시료는 다중패커시스템이 설치된 심부시추공으로부터 심도별로 채취되었으며, 계속적인 지화학 및 동위원소에 대한 모니터링이 진행되고 있다. 심부지하수는 pH가 약10.0이며 Na-HCO$_3$형으로 지화학적으로 특징되며, 지표로 250m이하의 심도에서는 거의 동일한 지화학적 특성을 보인다. 동위원소결과는 심부지하수는 천수기원임을 보이며, 천부지하수에 비해 약500~1,000m 높은 고도에서 함양되었음을 보여준다. 250m이하의 심부지하수는 50년이상의 체류시간을 갖음을 나타낸다.

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

• The Journal of the Petrological Society of Korea
• /
• v.11 no.3_4
• /
• pp.182-199
• /
• 2002

We attempted to show the evolution of the magma and the geochemical characteristics of dikes and dike swarms by using the petrographic and geochemical data from 287 dikes, SE Korea. The dikes can be divided into mafic, intermediate, and felsic dikes in the field. And each of them is subdivided into three groups, two groups, and two groups, respectively. The group (I) among the mafic dikes most pervasively occurs and are distributed in both sides of the Yeonil Tectonic Line (YIL), which petrographic and geochemical characteristics are the same. These facts thus, strongly support the results of the previous studies which showed that they were intruded contemporaneously and that YTL was a main tectonic line which restricted the crustal clockwise rotation during the Early Miocene. The geochemical characteristics are discriminated according to the seven groups divided petrographically. The mafic, intermediate and felsic dikes belong to basalt and basaltic andesite, andesite and facile, and rhyolite, respectively, and the magmas mostly belong to calc-alkaline series. The geochemical data indicate that there were the fractional crystallizations of olivine, clinopyroxene, and plagioclase in the mafic dikes. And the content of characteristic elements and tectonic discrimination diagrams show that the dikes were formed from the magma related to the subduction of plate and that the tectonic setting was related to orogenic volcanic arc.

• Economic and Environmental Geology
• /
• v.30 no.5
• /
• pp.477-491
• /
• 1997

In the Bibong area of the western part of Chungcheongnam-do, ultramafic masses occur as discontinuous isolated lenticular bodies in the Precambrian Kyeonggi gneiss complex. They extend for about 200 m long to NNE directions which are parallel to fault lines in the gneiss complex. The ultramafic masses contact with the adjacent gneiss complex as steeply dipping faults. They are dunites and harzburgites and many of them are partially or completely serpentinized. The ultramafic rocks dominantly show protogranular, equigranular and equigranular-$m{\grave{o}}saic$ textures. They also show porphyroclastic (megacrystic) or recrystallized textures reflecting several stages of metamorphism. They contain varying amounts of olivine $(Fo_{89-92})$, enstatitic to bronzitic orthopyroxene, diopsidic clinopyroxene, tremolitic to pargasitic hornblende, and spinel with serpentine, talc, chlorite, calcite and magnetite. The ultramafic rocks have high magnesium numbers and transitional element contents, low alkali contents and show deplete REE patterns. Comparing with available data, geochemical and mineralogical characteristics shown in the ultramafic rocks of the Bibong area are similar to those of worldwide mantle xenoliths and orogenic related ultramafic rocks. The field evidences, petrographical, geochemical and mineralogical characteristics shown in the ultramafic rocks of the Bibong area are similar to alpine type ultramafic rocks emplaced into the crust by the faulting as mantle slab types. With the petrographical characteristics, these mineralogical compositions suggest that the ultramafic rocks of the Bibong area have experienced several stages of retrogressive metamorphism in a condition ranging from the upper amphibolite facies to greenschist facies.

• Economic and Environmental Geology
• /
• v.34 no.3
• /
• pp.255-269
• /
• 2001

The geochemical studies on groundwater in the borehole, which is straddled by multi-packer (MP) system, were carried out from a volcanic terrain in the Yeosu area. The pH of groundwater collected from selected sections in the MP-installed borehole is much higher (up to 9.6) than that of the borehole groundwater (7.0-7.9) collected using conventional pumping technique. Hydrochemistry shows that the groundwater has a typical chemical change with increasing sampling depth, suggesting that the groundwater is evolved through water-rock interaction along the fracture-controlled flow paths. The groundwater from the deeper part (138-175 m below the surface) in borehole KI is characterized by the Ca-C11 type with high Ca (up to 160 mg/L) and Cl (up to 293 mg/L) contents, probably reflecting seawater intrusion. The groundwater also has high sodium and sulfate contents compared to the waters from other boreholes. These observed groundwater chemistry is explained by the cation exchange, sulfide oxidation, and mixing process with seawater along the flow path.

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