• Communications of the Korean Mathematical Society
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• v.18 no.3
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• pp.439-447
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• 2003

Let (equation omitted) be a symmetrizable Kac-Moody algebra with the indecomposable generalized Cartan matrix A and W be its Weyl group. Let $\theta$ be the highest root of the corresponding finite dimensional simple Lie algebra ${\gg}$ of g. For the type ${A_N}^{(r)}$, we give an element $\omega_{o}\;\in\;W$ such that ${{\omega}_o}^{-1}({\{\Delta\Delta}_{+}})\;=\;{\{\Delta\Delta}_{-}}$. And then we prove that the degree of nilpotency of the subalgebra (equation omitted) is greater than or equal to $ht{\theta}+1$.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2006.04a
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• pp.360-364
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• 2006

물수지 분석을 통해서 유역의 수문순화 체계를 이해하기 위해서는 무엇보다 필요한 인자가 증발산량이다. 장기간에 걸쳐 연구유역에서 수소와 산소 동위원소를 이용하여 증발산량을 산정하였다. 물 분자를 이루는 이상적인 추적자인 수소와 산소 강우를 풍수기($4{\sim}10$월)와 갈수기(11월$\sim$3월)로 나누어 수소와 산소 동위원소 조성을 강수량 가중 평균치를 구하고 이 값을 지하수의 수소와 산소 동위원소 조성 값과 비교하여 증발산량을 산정한 것이다. 이러한 시도는 증발산량의 산정이 단순한 경험식이나 열전도 가정식이 아닌 실측했다는데 의의가 있다.

• The Korean Journal of Quaternary Research
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• v.17 no.2
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• pp.165-165
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• 2003

A borehole core ECSDP-102 (about 68.5 m long) has been investigated to get information on paleoenvironmental changes in response to the sea-level fluctuations during the period of late Quaternary. Several AMS $\^$14/C ages show that the core ECSDP-102 recorded the depositional environments of the northern East China Sea for approximately 60 ka. The Yangtze River discharged huge amounts of sediment into the northern East China Sea during the marine isotope stage (MIS) 3. In particular, $\delta$$\^$13/Corg values reveal that the sedimentary environments of the northern East China Sea, which is similar to the Holocene conditions, have taken place three times during the MIS 3. It is supported by the relatively enriched $\delta$$\^$13/Corg values of -23 to -21$\textperthousand$ during the marine settings of MIS 3 that are characterized by the predominance of marine organic matter akin to the Holocene. Furthermore, we investigated the three Holocene sediment cores, ECSDP-101, ECSDP-101 and YMGR-102, taken from the northern East China Sea off the mouth of the Yangtze River and from the southern Yellow Sea, respectively. Our study was focused primarily on the onset of the post-glacial marine transgression and the reconstructing of paleoenvironmental changes in the East China Sea and the Yellow Sea during the Holocene. AMS $\^$14/C ages indicate that the northern East China Sea and the southern Yellow Sea began to have been flooded at about 13.2 ka BP which is in agreement with the initial marine transgression of the central Yellow Sea (core CC-02). $\delta$$\^$18/O and $\delta$$\^$13/C records of benthic foraminifera Ammonia ketienziensis and $\delta$$\^$13/Corg values provide information on paleoenvironmental changes from brackish (estuarine) to modem marine conditions caused by globally rapid sea-level rise since the last deglaciation. Termination 1 (T1) ended at about 9.0-8.7 ka BP in the southern and central Yellow Sea, whereas T1 lasted until about 6.8 ka BP in the northern East China Sea. This time lag between the two seas indicates that the timing of the post-glacial marine transgression seems to have been primarily influenced by the bathymetry. The present marine regimes in the northern East China Sea and the whole Yellow Sea have been contemporaneously established at about 6.0 ka BP. This is strongly supported by remarkably changes in occurrence of benthic foraminiferal assemblages, $\delta$$\^$18/O and $\delta$$\^$13/C compositions of A. ketienziensis, TOC content and $\delta$$\^$13/Corg values. The $\delta$$\^$18/O values of A. ketienziensis show a distinct shift to heavier values of about 1$\textperthousand$ from the northern East China Sea through the southern to central Yellow Sea. The northward shift of $\^$18/O enrichment may reflect gradually decrease of the bottom water temperature in the northern East China Sea and the Yellow Sea.

• Economic and Environmental Geology
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• v.34 no.2
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• pp.217-226
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• 2001

Stable isotope, paleoceanographic and sedimentological analyses were carried out along the core Ml5612 from the Mid-Atlantic Ridge. Distinct negative ${\delta}^{18}O anomalies punctuate the planktonic isotope records and correlate with the Heinrich-IRD cvents. The IRD layer in the corc contains varying amounts of quartz, K-feldspar, plagioclase, calcite, dolomite and mica, in which detrital carbonate contributes between I and 13% (except H3 and H6). Anomalies are strongest in the N. pachydenna (sin.) isotope record. Systematic changes in the ${\delta}^{18}O offset of G. hul/aides and G. inJlata signify variations in mid-latitude thermocline structure. In conjunction with negative benthic ${\delta}^{13}C anomalies, the data document a stronger contribution of a ${\delta}^{13}C depleted, nutrient-rich water mass during the IRD events. The ${\delta}^{13}C amplitude of > 1 $\textperthousand$ between 25 and 57 ka indicates changes between northern source (NADW) and southern source (AABW) water masses at this site. The IRD layers in the core Ml56l2 are correlative with those from the core S075-26KL and DSDP 609. The IRD layers from the Portuguese margin arc coeval with HI, H2 and H4 of the open North Atlantic. This similarity (and/or synchronicity in both regions may have been resulted from common changes in a North Atlantic thermohaline switch.

• Korean Journal of Mathematics
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• v.18 no.1
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• pp.45-52
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• 2010

Generalizing $Lindel{\ddot{o}}f$ frames and almost compact frames, we introduce a concept of almost $Lindel{\ddot{o}}f$ frames. Using a concept of ${\delta}$-filters on frames, we characterize almost $Lindel{\ddot{o}}f$ frames and then have their permanence properties. We also show that almost $Lindel{\ddot{o}}f$ regular $D({\aleph}_1)$ frames are exactly $Lindel{\ddot{o}}f$ frames. Finally we construct an almost $Lindel{\ddot{o}}fication$ of a frame L via the simple extension of L associated with the set of all ${\delta}$-filters F on L with ${\bigvee}\{x^*{\mid}x{\in}F\}=e$.

• Journal of the korean society of oceanography
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• v.34 no.1
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• pp.43-48
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• 1999

The latest-Quaternary paleoceanographic history of the Ulleung Basin, the East Sea (the Sea of Japan) is reconstructed on the base of planktonic foraminifera, oxygen and carbon isotopes, and accelerator mass spectrometer radiocarbon (AMS-$^{14}$C) data from two cores. Sinistral populations of Neogloboquadrina pachyderma are dominant during the last glacial period while dextral forms of Neogloboquadrina pachydeyma are abundant in the Holocene. An abrupt increase in ${\delta}^{18}$O values in both cores that began about 11 ka B.P may indicate the Younger Dryas cooling episode. A low-salinity event, marked by light ${\delta}^{18}$O values (0-1 %), is observed before the Younger Dryas event. As previous works suggested, the low-salinity event is probably due to the freshening of surface water caused by fresh water input from Huang Ho river and/or the excess of precipitation over evaporation. The lowest salinity water in the Ulleung Basin was probably continued from approximately 18 ka B.P. to 15 ka B.P. The ${\delta}^{18}$O values have gradually decreased since the Younger Dryas as a result of the continuous inflow of the warm Tsushima Current into the East Sea.

• Journal of the Korean earth science society
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• v.21 no.4
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• pp.449-468
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• 2000

The Ordovician Chongson Limestone deposited in the carbonate ramp to the rimmed shelf shows diverse diagenetic features. The marine diagenetic feature appears as isopachous cements surrounding ooids and peloids. Meteoric diagenetic features are recrystallized finely and coarsely crystalline calcite, evaporite casts filled with calcite, and isopachous sparry calcite surrounding ooid grains. Shallow burial diagenetic features include wispy seam, microstylolite, and dissolution seam whereas deep burial features include stylolite, burial cements. blocky calcite with twin lamellae, and poikilotopic calcite. Dolomites consist of very finely to finely crystalline mosaic dolomite formed as supratidal dolomite, disseminated dolomite of diverse origin, patchy dolomite formed from bioturbated mottles, and saddle dolomite of burial origin. Silicified features include calcite-replacing quartz and fracture-filling megaquartz. Burial cements characterized by poikilotopic texture show ${\delta}^{18}$O value of -10.4 %$_o$ PDB, ${\delta}^{13}$C value of -1.0%$_o$ PDB and 504ppm Sr, 3643ppm Fe, and 152ppm Mn concentrations. Finely and coarsely crystalline limestones show similar ${\delta}^{18}$O and ${\delta}^{13}$C value to those of burial cements; however, they show lower Sr and higher Fe and Mn concentrations than burial cements. This suggests that very finely and coarsely crystalline limestones were recrystallized in freshwater and then they were readjusted geochemically in the burial setting whereas the burial cements were formed in relatively high temperature and low water/rock ratio conditions. Very finely and finely crystalline mosaic dolomites with ${\delta}^{18}$O value of -8.2%$_o$ PDB, ${\delta}^{13}$C value of -1.9 %$_o$ PDB, and 213ppm Sr, 3654ppm Fe, and 114ppm Mn concentrations, respectively are interpreted to have been formed penecontemporaneously in supratidal flat and then recrystallized in the low water/rock ratio burial environment. Geochemical data suggest that the low water/rock ratio burial environment was the dominant diagenetic setting in the Chongson Limestone. The Chongson Limestone has experienced marine and meteoric diagenesis during early diagenesis. With deposition of Haengmae and Hoedongri formations part of the Chongson Limestone was buried beneath these formations and it experienced shallow burial diagenesis. During the Devonian the Chongson Limestone was tectonically deformed and subaerially exposed. During the Carboniferous to the Permian about 3.3km thick Pyongan Supergroup was deposited on the Chongson Limestone and the Chongson Limestone was in deep burial depths and stylolite, burial cements, blocky calcite and saddle dolomite were formed. After this burial event the Chongson Limestone was subaerially exposed during the Mesozoic and Cenozoic by three periods of tectonic disturbance including Songnim, Daebo and Bulguksa disturbance. Since the Bulguksa disturbance during Cretaceous and early Tertiary the Chongson Limestone has been subaerially exposed.

• Economic and Environmental Geology
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• v.27 no.4
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• pp.345-361
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• 1994

Lens shaped titanomagnetite ore bodies in the Soyeonpyeong iron mine are embedded in amphibolites, which were intruded into Precambrian metasediments such as garnet-mica schist, marble, mica schist, and quartz schist. Mineral chemistry, K-Ar dating and hydrogen and oxygen stable isotopic analysis for the amphibolites and titanomagnetite ores were conducted to interpret petrogenesis of amphibolite and ore genesis of titanomagnetite iron ore deposits. Amphibolites of igneous origin have unusually high content of $TiO_2$, ranging from 0.94 to 6.39 wt.% with an average value of 4.05 wt.%. REE patterns of the different lithology of the amphibolite show the similar trend with an enrichment of LREE. Amphiboles of amphibolites are consist mainly of calcic amphiboles such as ferro-hornblende, tschermakite, ferroan pargasite, and ferroan pargasitic hornblende. K-Ar ages of hornblende from amphibolite and gneissic amphibolite were determined as $440.04{\pm}6.39Ma$ and $351.03{\pm}5.21Ma$, respectively. This indicates two metamorphic events of Paleozoic age in the Korean peninsula which are correlated with Altin orogeny in China. The titanomagnetite mineralization seems to have occurred before Cambrian age based on occurrence of orebodies and ages of host amphibolites. The Soyeonpyeong iron ores are composed mainly of titanomagnetite, ilmenite, and secondary minerals such as ilmenite and hercynite exsolved in titanomagnetite. The temperature and the oxygen fugacity estimated by the titanomagnetite-ilmenite geothermometer are $500{\sim}600^{\circ}C$ (ave. $550^{\circ}C$) and about $2{\pm}10^{-23}bar$, respectively. Hornblendes from ores and amphibolites which responsible for magnetite ore mineralization, have a relatively homogeneous isotopic composition ranging from +0.8 to +3.9 ‰ in ${\delta}^{18}O$ and from -87.8 to -113.3 ‰ in ${\delta}D$. The calculated oxygen and hydrogen isotopic compositions of the fluids which were in equilibrium with hornblende at $550^{\circ}C$, range from 2.8 to 5.9‰ in ${\delta}^{18}O_{H2O}$ and from -60.41 to -81.31 ‰ in ${\delta}D_{H2O}$. The ${\delta}^{18}O_{H2O}$ value of magnetite ore fluids are in between +6.4 to + 7.9 ‰. All of these values fall in the range of primary magmatic water. A slight oxygen shift means that $^{18}O$-depleted meteoric water be acted with basic fluids during immiscible processes between silicate and titaniferous oxide melt. Mineral chemistry, isotopic compositions, and occurences of amphibolites and orebodies, suggest that the titanomagnetite melt be separated immisciblely from the titaniferous basic magma.

• Economic and Environmental Geology
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• v.30 no.1
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• pp.25-33
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• 1997

The purpose of this study is to examine the feasibility of using stable isotopes as a hydrologic tracer, and to elucidate the groundwater circulation system and the source of S component dissolved in thermal water of the Chonju Jukrim thermal spring district based on the O, H and S isotopic variabilities of environmental materials including bedrock, rainwater, surface water, shallow subsurface water and thermal spring water. The ${\delta}^{18}O$ and ${\delta}D$ of subsurface waters and surface water show highly restricted range and plotted on the same meteoric water line as a ${\delta}D=8{\delta}^{18}O+19$ line, and derivate from the mean annual isotopic composition of the rain water but are analogous to those of rain waters precipitated during winter season, indicating that ground waters are originated from the meteoric water and are strongly affected by the seasonal variation of air mass. Thermal spring waters are more depleted in ${\delta}^{18}O$ and ${\delta}D$ than those of shallow ground water and surface water. It can be explained by the difference of recharge area. The hydrochemical properties of subsurface waters and surface water devide into two groups: $Ca(HCO_3)_2$ type including shallow subsurface water and surface water, and $Na(HCO_3)$ type of thermal spring waters. The ${\delta}^{34}S$ values of thermal spring water show very high positive and quitely distinct from those of shallow subsurface water and surface water that are similar to those of bed rocks, indicating that sulfate dissolved in thermal spring water has not only a terrigenic origin, but also originates partially from the foreign source containing very heavy ${\delta}^{34}S$ component such as an ancient sea water. However, the presence of $H_2S$ can not be ignore the affact of the isotopic fractionation to explaine the heavy ${\delta}^{34}S$ of thermal spring water. Overall, the Oxygen and Hydrogen stable isotopes can identify the source and the circulation system of the natural waters and the S-isotopes can provide a crucial clue on tracing the dissolved material transports in the circulation system of the natural water.

• Economic and Environmental Geology
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• v.40 no.5
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• pp.517-535
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• 2007

Two distinctive Mesozoic hydrothermal systems occurred in South Korea: the Jurassic/Early Cretaceous(ca. $200{\sim}130$ Ma) deep-level ones during the Daebo orogeny and the Late Cretaceous/Tertiary(ca. $110{\sim}45$ Ma) shallow hydrothermal ones during the Bulgugsa event. The Mesozoic hydrothermal system and the metallic mineralization in the Korean Peninsula document a close spatial and temporal relationship with syn- to post-tectonic magmatism. The calculated ${\delta}^{18}O_{H2O}$ values of the ore-forming fluids from the Mesozoic metallic mineral deposits show limited range for the Jurassic ones but variable range for the Late Cretaceous ones. The orogenic mineral deposits were formed at relatively high temperatures and deep-crustal levels. The mineralizing fluids that were responsible for the formation of theses deposits are characterized by the reasonably homogeneous and similar ranges of ${\delta}^{18}O_{H2O}$ values. This implies that the ore-forming fluids were principally derived from spatially associated Jurassic granitoids and related pegmatite. On the contrary, the Late Cretaceous ferroalloy, base-metal and precious-metal deposits in the Taebaeksan, Okcheon and Gyeongsang basins occurred as vein, replacement, breccia-pipe, porphyry-style and skarn deposits. Diverse mineralization styles represent a spatial and temporal distinction between the proximal environment of subvolcanic activity and the distal to transitional condition derived from volcanic environments. The Cu(-Au) or Fe-Mo-W deposits are proximal to a magmatic source, whereas the polymetallic or the precious-metal deposits are more distal to transitional. On the basis of the overall ${\delta}^{18}O_{H2O}$ values of various ore deposits in these areas, it can be briefed that the ore fluids show very extensive oxygen isotope exchange with country rocks, though the ${\delta}D_{H2O}$ values are relatively homogeneous and similarly restricted.