• Economic and Environmental Geology
• /
• v.39 no.2 s.177
• /
• pp.151-162
• /
• 2006

Characteristics and changes of groundwater qualify were investigated in a riverbank filtration area at Daesan-myeon, Changwon City, Korea. The total dissolved solids (TDS) in groundwater samples collected in October were much less than that in March, indicating the mixing with recharged water from precipitation, as well as the changes of dissolved oxygen profiles at monitoring wells from March to October. Redox processes at depths appeared to trigger Fe and Mn contamination of groundwater in riverbank deposits. Amorphous oxyhydroxides md carbonate minerals such as $MnCO_3$ were probably the reactive phases for dissolved Fe and Mn, respectively. Groundwater contamination by nitrate-nitrogen $(NO_3-N)$ was controlled by the redox processes and subsequent denitrification at the sampled depths. Distribution of $NO_3-N$ concentrations at monitoring wells suggested that the nitrate contaminants were originated from agricultural facilities on the riverbank deposits. Some of monitoring wells, DS-2, D-2, DS-3, SJ-1, and SJ-3, were only partially penetrated into the sand/gravel aquifer, and subsequently, could not fully function to detect the water quality changes for the pumping wells. Proper measures, with regulating agricultural activities in the riverbank deposits, should be carried out to prevent groundwater contamination of the riverbank filtration area.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.34 no.3
• /
• pp.268-278
• /
• 2001

To investigate sedimentary facies and environmental changes of the Nakdong River Estuary and its adjacent coastal area, the grain size analysis and measurement of organic matter, calcium carbonate, clay mineral and metallic elements were carried out for forty surface sediment samples. Based on regional distribution pattern and characteristics of the surface sediments, sedimentary facies in the study area can be divided into sand facies (TYPE I), mud facies (TYPE II) and sand-mud mixed facies (TYPE III). TYPE III is the transition of TYPE I and TYPE II in every aspects of sediment characteristics. It suggests that TYPE III may have been formed by the mixture of two different source of sediment : one derived from Nakdong River and the other resuspended fine-grained sediments from the Jinhae Bay by winnowing action during floods or storms. Among many aspects of environmental change after the construction of the Nakdong Barrage, the most significant is the increase of sand content off the sand barrier region. It could be explained by several reasons including decreased input of fine-grained sediment from river, increased hydrodynamic energy level off the sand barrier region and artificial effects such as dredging and dumping.

• Economic and Environmental Geology
• /
• v.42 no.1
• /
• pp.27-53
• /
• 2009

A 30-m-thick Middle Ordovician Jigunsan Shale exposed along the southern limb of the Backunsan (Baekunsan) Syncline, Taebacksan (Taebaeksan) basin, has been simply considered as a transgressive shale sequence onlapped the underlying Maggol platform carbonates. Results of this study, however, suggest that majority of the Jigunsan Shale be interpreted as a regressive shale sequence downlapped onto a thin (ca. 240 cm) marine stratigraphic unit consisting of organic-rich (>3 wt.% of TOC) black shales in the lower Jigunsan Shale, which was accumulated at the time of maximum regional transgression. Detailed stratigraphic analysis in conjunction with XRD, XRF, and ICP-MS as well as Rock-Eval pyrolysis allows the thin marine stratigraphic unit in the Jigunsan Shale to define a condensed section that was deposited in a distinctive euxinic zone formed due to expansion of pycnocline during the early highstand phase. As well, a number of stratigraphic horizons of distinctive character that may have sequence stratigraphic or environmental significance, such as transgressive surface, maximum flooding surface, maximum sediment starvation surface, and downlap surface, are identified in the lower Jigunsan Shale. In the future, these stratigraphic horizons will provide very useful information to make a coherent regional stratigraphic correlation of the Middle Ordovician strata and to develop a comprehensive understanding on stratigraphic response to tectonic evolution as well as basin history of the Taebacksan Basin.

• The Korean Journal of Petroleum Geology
• /
• v.3 no.1 s.4
• /
• pp.16-27
• /
• 1995

The Early Miocene Temblor Formation forms an important sandstone reservoir at Kettleman North Dome oil field, California. Sandstones are mostly arkosic in composition except deepest sandstones containing much volcanic rock fragments. Arranged in paragenetic sequence prior to feldspar alteration, the Temblor sandstones contain cements of early calcite, dolomite, quartz, albite, mixed-layer ohloriteismectite (C/S) and smectite, and anhydrite. Diagenetic changes associated with feldspar are albitization of plagioclase, late calcite and laumontite cementation and grain replacement, plagioclase dissolution, and kaolinite cementation. Plagioclase albitization and late calcite and laumontite cementation in Temblor sandstones occurred at the time of maximum burial with temperatures up to $130^{\circ}C$. Volcanic plagioclases were selectively albitized. Most diagenetic changes are interpreted to have occurred before the maior uplift which occurred within the last one million years ago. Since then to the time of hydrocarbon emplacement plagioclase dissolution and kaolinite cementation occurred. This reaction occurred in relatively closed system due to the occurrence of kaolinite next to the site of plagioclase dissolution. Unaltered part of volcanic plagioclase and plutonic plagioclase which escaped albitization during maximum burial were preferentially dissolved to make plagioclase porosity. Secondary porosity resulting from dissolution of plagioclase and carbonate and anhydrite cements was mainly produced by formation waters containing organic acids released during atagenesis of organic matter.

• The Journal of Engineering Geology
• /
• v.14 no.3 s.40
• /
• pp.259-272
• /
• 2004

The purpose of this study is to investigate the effect of hydrochemical variation of groundwater on the gas tigtness in an unlined oil storage cavern. The groundwater chemistry is greatly influenced by the seawater mixing, the water curtain and the dissolution of grounting cements. The chemical composition of groundwater greatly varies ac-cording to both the location of monitoring wells and the sampling period. Most of groundwater shows alkaline pH and high electrical conductivity. The chemical types of groundwater show the dominant order as follows : Na-Cl type > Ca-Cl type > $Ca-HCO_3(CO_3)$ type. Thermodynamic equilibrium state between chemical composition of groundwater and major minerals indicates that carbonate minerals except clay minerals can be precipitated as a secondary mineral. It means that the secondary precipitates can not greatly exerts the clogging effect into fracture aperture in rock mass around oil storage cavern. The content of total organic carbon (TOC) shows a slightly increasing trend from initial stage to late stage. The $EpCO_2$ was computed so as to assess the gas contribution on the $CO_2$ in groundwater. The $EpCO_2$ of 0$\~$41.3 indicates that the contribution of oil gas on $CO_2$ pressure in groundwater system can be neglected.

• 한국해양학회지
• /
• v.29 no.4
• /
• pp.338-356
• /
• 1994

Sediment samples from the continental shelf of the South Sea of Korea are analysed to determine the concentration of Al, Fe, Mn, cu, Ni, Zn, Co, Cr and Pb. among these samples, fine-grained sediments were also analysed by a sequential extraction technique to know geochemical forms of the metals in this environments. The total concentration of Al, Fe, Cr, Ni, Cu and Zn in bulk sediments decreased gradually with the increase of distance from the coastal zone. This distribution patterns are well coincide with grain size distribution. However, the patterns of Mn, co and Pb do not follow such and overall distribution. The concentration of Pb, particularly, did not show any features in areal distribution, which may be result from different pathways to the sediments, compared to the other metals. the speculation data show that a considerable amount of Cd, Mn and Co are bounded in the carbonate fraction, accounting for 42.8%, 40.3% and 30.6%, respectively. Cu, Zn, Mn and Fe are largely associated to oxide fraction with proportions of 34.4%, 23.1%, 15.5% and 13.7%, respectively. However, the metals in residual fraction account for more than 50% of the total metal concentration, except for Mn. These observations emphasize that residual fraction in the dominant component controlling the elemental concentration.quartz and glauconite grains.Accordingly,these sediments are interpreted as an extension part of transgressive sand deposit that are widely distributed on the continental shalf floor of southern Yellow Sea.

• Economic and Environmental Geology
• /
• v.35 no.4
• /
• pp.355-368
• /
• 2002

The multi-storied Daewonsa stone pagoda (Treasure No. 1112) in the Sancheong, Korea was studied on the basis of deterioration and geological safety diagnosis. The stone pagoda is composed mainly of granitic gneiss, partly fine-grained granitic gneiss, leucocratic gneiss, biotite granite and ceramics. Each rock of the pagoda is highly exfoliated and fractured along the edges. Some fractures in the main body and roof stones are treated by cement mortar. This pagoda is strongly covered with yellowish to reddish brown tarnish due to the amorphous precipitates of iron hydroxides. Dark grey crust by manganese hydroxides occur Partly, and some Part coated with white grey gypsum and calcite aggregates from the reaction of cement mortar and rain. As the main body, roof and upper part of the pagoda, the rocks are developed into the radial and linear cracks. Surface of this pagoda shows partly yellowish brown, blue and green patchs because of contamination by algae, lichen, moss and bracken. Besides, wall-rocks of the Daewonsa temple and rock aggregates in the Daewonsa valley are changed reddish brown color with the same as those of the pagoda color. It suggests that the rocks around the Daewonsa temple are highly in iron and manganese concentrations compared with the normal granitic gneiss which color change is natural phenomena owing to the oxidation reaction by rain or surface water with rocks. Therefore, for the attenuation of secondary contamination, whitening and reddishness, the possible conservation treatments are needed. Consisting rocks of the pagoda would be epoxy to reinforce the fracture systems for the structural stability on the basements.

• 한국해양학회지
• /
• v.22 no.3
• /
• pp.130-142
• /
• 1987

Sedimentological characteristics of the surface sediments in the southern sea off Cheju Island are described from analyses of bottom sediments. The sediments are subdivided into seven textural classes, muddy sand, slightly gravelly muddy sand, sand, clayey sand, sandy clay, sandymud, silty sand. Sand-size sediments are distributed in the southeastern part and/or around the Island, whereas sandy and muddy sediments are mainly distributed in the central and southern parts of the study area. A small portion of mud patch is located in the southwestern part of the area. According to the textural parameters analysis, sediments in the study area are poorly sorted(av.2.52 ), positive skewed(av.1.61 ), leptokurtic(av.1.74 ), transported by saltation and/or suspension, and roundness of quartz is varied from angular to surrounded, which suggesting that the depositional environment is not simple. The calcium carbonate content is on the average 26.99%, and commonly abundant in sand-size sediments, whereas organic matter content in the bulk sediment is on the average 6.70% and usually dominant in fine-grained sediments.Light minerals consist of quartz(av56.01%),Na-Ca feldspar(av.6.15%),K-feldspar(av.9.22%) and rock fragments(av28.11%).The contect onquartz and K-feldspar increases continuously away from the Cheju Island. As a result of geochemical analysis,concentrations of the elements are as follow:Zn:19.42-43.52 ppm (av.30.67ppm),Mn:50-304 ppm(av139.39ppm),Cr:3.54-10.68ppm(av6.50ppm),Pb:5.52-41.68ppm(av.15.60ppm), Co:7.08-14.68ppm (av.10.78ppm),Ni:19.70-42.42ppm(av.29.57ppm),Cu:3.14-9.12ppm(av.5.14ppm),Fe:0.48-2.08% (av1.22%),Ca:0.32-13.16%(av6.60%),Al:0.06-0.08%(av.0.27%),Mg:0.12-0.76%(av.0.53%)na:0.11-0.51%(av.0.36%) Ag:0.48-4.08ppm(av.1.22ppm).Among these elements,the content of Zn,Cu,Cr,Mn,Fe,Al,Mg,Pb and Na increase toward the southwestern area,while the content of Ca and Ag SHOWS the reversed distribution trend.Such a distribution pattern seems to imply that spatial distrivution of heavy metals is closely related to the variation in grain size. X-ray diffractogram show that the minerals in clay from the southwestern mud patch are illite ,chlorite, kaolinte,feldspar and calcite.The bulk of illite in th mud zone is believed to be originated from Huanghe and Yangytze River.The mud patch in this region contains the diagnostic calcite peak,and the concentration of Ca,ni,Pb,Ag are similar to Huanghe type,which indicates that the greater part of these clay fractions may have been derived from the Huanghe River.

• Economic and Environmental Geology
• /
• v.35 no.2
• /
• pp.113-120
• /
• 2002

Oxygen and hydrogen isotopic compositions of stream water in the Han river basin are expressed by the equation of $\delta$D=6.6$\delta$$^{18}$ O-7.4, which is not satisfy the meteoric water line ($\delta$D=8$\delta$$^{18}$ O+10). It might be depended on the local climatic condition and the evaporation effect in the Han river basin. The $\delta$$^{18}$ O and $\delta$D values of stream water in the Han river basin range from -8.2 to -10$\textperthousand$ (avg. -9.1$\textperthousand$) and -60 to -96$\textperthousand$ (avg. -69$\textperthousand$), respectively. The stream water from the South Han river (8$\delta$$^{18}$ O= -8.9~ -10$\textperthousand$, avg.-9.3$\textperthousand$ $\delta$D: -66~ -96$\textperthousand$, avg.-69$\textperthousand$) is slightly more depleted in $^{18}$ O and D than those of North Han river ($\textperthousand$$^{18}$ O= -8.4~ -9.7$\textperthousand$, avg. -9.2$\textperthousand$, $\delta$D= -64~ -95$\textperthousand$, avg. -69$\textperthousand$). It reflects more altitude effect than the effect of latitude and Inflow of the $^{18}$ O eniched S $O_4$$^{2-}$ and HC $O_3$- from the carbonate rock and sulfide minerals in the Taebagsan and Hwanggangri mineralized zone. The Main stream water of the Han river having $\delta$D: -60~ -76$\textperthousand$ (avg.-68$\textperthousand$) and $\textperthousand$$^{18}$ O= -8.2~-10$\textperthousand$ (avg.9.0$\textperthousand$) is enriched in $^{18}$ O compared to the South and North Han river waters, which is caused by the evaporation effect. Binary simple mixing ratio of the Main Han river water between South and North Han river waters was obtained to be 6 : 4 by the isotopic data, suggesting a strong influence of South Han river water to the Main Han river water.

• Journal of Soil and Groundwater Environment
• /
• v.6 no.4
• /
• pp.51-59
• /
• 2001

Column and box tests were performed to investigate the removal efficiency of NAPL using the surfactant enhanced flushing In heterogeneous medium. Homogeneous Ottawa sand and heterogeneous soil were used to verify the increase of remediation efficiency for the surfactant enhanced flushing in column test. Box tests with two different heterogeneous sub-structure were performed to quantify the capability of the surfactant enhanced flushing as a remediation method to remove NAPL from the heterogeneous medium. Two different grain size sand layers were repeated in the box to simulate the heterogeneous layer formation and the modified fault structure was built to simulate the fault system in the box. O-xylene as a LNAPL and PCE as a DNAPL were used and oleamide as a non-ionic surfactant. The maximum NAPL effluent concentration with 1% oleamide flushing in the homogeneous column test increased about 460 times compared to that with only water flushing and about 250 times increased in the real soil column test. In heterogeneous medium, the maximum effluent concentration increased about 150 times in 1% oleamide flushing and most of NAPL were removed from the box within 8 pore volume flushing, suggesting that the removal efficiency increased very much compared to in only water flushing. Results investigated the capability of the surfactant enhanced remediation method to remove NAPL even in heterogeneous medium.