ARD generation and corrosion potential of exposed roadside rockmass at Boeun and Mujoo,South Korea     

Sang Woo Ji  Young Wook Cheong  Gil Jae Yim  Jayanta Bhattacharya 《Environmental Geology》2007,52(6):1033-1043

Acid rock drainage (ARD) is a longstanding problem often associated with the resulting corrosion due to the acidity generated from sulfidic oxidation. To evaluate characteristics of ARD and corrosion, samples from the road side rock mass of Boeun and Mujoo were analysed using X-ray diffraction, acid/base accounting and Leaching tests. The results indicated that many samples had a pyritic origin and can be regarded as acid-generating rocks. The Leaching test showed that the average pH of the leachates of samples from both Boeun and Mujoo were moderately acidic, ranging from 3 to 4. Interestingly, as acidity increases from pH 4, the SO₄₋, Fe, Al and Mg concentrations increase abnormally. Samples from roadside slope of Mujoo showed high corrosive potential. Maximum sulfide oxidation rate of a sample taken from Mujoo was as high as 5,166 mg/kg/week.  相似文献   

Stabilization of arsenic-contaminated mine tailings using natural and calcined oyster shells   总被引：1，自引：0，他引：1  

Deok Hyun Moon  Kyoung-Woong Kim  In-Ho Yoon  Dennis G. Grubb  Dae-Yewn Shin  Kyung Hoon Cheong  Hyung-Il Choi  Yong Sik Ok  Jeong-Hun Park 《Environmental Earth Sciences》2011,64(3):597-605

Natural oyster shells (NOS) and calcined oyster shells (COS) were used to immobilize arsenic (As) from contaminated mine tailings. In addition, a blend of Portland cement (PC)/cement kiln dust (CKD) was used as a stabilizing agent. The Korean Standard Test (KST) method (1 N HCl extraction) was used to evaluate the effectiveness of the treatment. The experimental results showed that COS effectively immobilized As in treated mine tailings. Specifically, an As concentration less than 1 mg L⁻¹ was obtained following COS treatment at 25 and 30 wt%. However, all the samples subjected to NOS treatments failed the Korean warning standard of 1.2 mg L⁻¹ after 28 days of curing. All of the COS-PC treatments were successful meeting the Korean warning standard after 7 days of curing. However, the PC-only treatment failed to meet the Korean warning standard. Similarly, the CKD-only treatment was failed to meet the Korean warning standard after 7 days of curing. However, the COS-CKD treatment showed that when the COS content was greater than 20 wt%, less than 1 mg L⁻¹ of As leachability was obtained. Scanning electron microscopy–energy dispersive X-ray spectroscopy (SEM–EDX) showed needle-like and torpedo-like Ca–As phases in the COS-treated samples suggesting that As was strongly associated with Ca and O. X-ray absorption near edge structure (XANES) analyses confirmed that As(V) was prevalent in the tailings and that there were no changes in As speciation following NOS or COS treatment.  相似文献   

Spectral analysis method for a limited area using the eigenmodes of the spherical Laplacian operator     

Ja-Rin Park  Hyeong-Bin Cheong 《Asia-Pacific Journal of Atmospheric Sciences》2013,49(5):665-674

We propose a spectral analysis method using the eigenmodes of the spherical Laplacian operator on the limited area domain. Two numerical methods are considered for the horizontal discretization: One uses the half-ranged Fourier series for both longitudinal and latitudinal directions, and the other uses the Fourier finite-element method with piecewise linear basis functions for the latitudinal direction. The field variable for the two numerical algorithms is represented as linear combinations of the eigenvectors of the Laplacian operator on the limited area domain; we define the one-dimensional spectrum with the eigenvector coefficients as a function of the indices equivalent to the total wavenumbers of the Laplacian operator on the global domain. The spatial robustness of this method was verified through the self-consistency test comparing the spectra of isotropic Gaussian bells on the sphere. We used the method in the kinetic energy spectral analysis for a limited area with global atmospheric data, and compared the results for different seasons. The kinetic energy spectra represented the well-known characteristics with scale and different powers with season.  相似文献   

Synmetamorphic granitoids (~ 490 Ma) as accretion indicators in the evolution of the Ol’khon terrane (western Cisbaikalia)     

T.V. Donskaya  D.P. Gladkochub  V.S. Fedorovsky  A.M. Mazukabzov  M. Cho  W. Cheong  J. Kim 《Russian Geology and Geophysics》2013,54(10):1205-1218

We present geological, structural, and geochemical data on synmetamorphic granitoids from the Tutai and South Ol’khon plutons of the Ol’khon terrane (Central Asian Fold Belt) with an estimation of the U–Pb zircon age of the Tutai granites. The structural and petrological data suggest the synfolding and synmetamorphic origin of the granitoids. The U–Pb zircon age of the Tutai granites (488.6 ± 8.0 Ma) almost coincides with the previously estimated age of quartz syenites from the South Ol’khon pluton (495 ± 6 Ma). The plutons occupy the same position in the regional structure. The granitoids underwent final deformations and metamorphism at 464 ± 11 Ma. The Tutai pluton consists of moderately potassic granites, whereas the South Ol’khon pluton is made up of quartz syenites and granites. The geochemical characteristics of the granites from both plutons (low Y and Yb contents, fractionated REE patterns) indicate their formation under conditions of garnet crystallization in deep crustal restite. The higher Y and Yb contents of the South Ol’khon quartz syenites as compared with those of the granites suggest the lack of equilibrium between the quartz syenite magmas and garnet parageneses during their formation or evolution. The Tutai and South Ol’khon granites were derived from quartz-feldspar crustal rocks, whereas the South Ol’khon quartz syenites might have originated from a mixed (crust-mantle) source. It is presumed that the granitoids formed within accretion-thickened crust. Early accretion, which has been first identified in the region, affected not only the Pribrezhnaya zone (the zone of the Tutai and South Ol’khon plutons) but also the entire Anga–Satyurty megazone of the Ol’khon terrane. The accretion ended with the convergence and oblique collision of the Ol’khon terrane and Siberian continent, when strike-slip tectonics became ubiquitous.  相似文献   

Uranium isotopes as a tracer of sources of dissolved solutes in the Han River,South Korea     

Jong-Sik Ryu  Kwang-Sik Lee  Ho-Wan Chang  Chang-Sik Cheong 《Chemical Geology》2009,258(3-4):354-361

The uranium (U) content and ²³⁴U/²³⁸U activity ratio were determined for water samples collected from Korea's Han River in spring, summer, and winter 2006 to provide data that might constrain the origin of U isotope fractionation in river water and the link between U isotope systematics in river waters and the lithological nature of the corresponding bedrock. The large difference in the major dissolved loads between the two major branches of the Han River, the North Han River (NHR) and South Han River (SHR), is reflected in the contrasting U content and ²³⁴U/²³⁸U activity ratio between the tributaries: low U content (0.08–0.75 nM; average, 0.34 nM) and small ²³⁴U/²³⁸U activity ratio (1.03–1.22; average, 1.09) in the NHR; and high U content (0.65–1.98 nM; average, 1.44 nM) and large ²³⁴U/²³⁸U activity ratio (1.05–1.45; average, 1.24) in the SHR. The large spatial differences in U content and ²³⁴U/²³⁸U activity ratio are closely related to both lithological differences between the two tributaries and groundwater input. The low U content and small ²³⁴U/²³⁸U activity ratio in the NHR arise mainly from a combination of surface and meteoric weathering of the dominant silicate rocks in this branch and congruent dissolution of already weathered (secular equilibrium) materials. In contrast, the high U content and large ²³⁴U/²³⁸U activity ratio in the SHR are ascribed to the dissolution of carbonates and black shales along with significant inputs of deep groundwater.  相似文献   

Lithospheric mantle signatures as revealed by zircon Hf isotopes of Late Triassic post‐collisional plutons from the central Korean peninsula,and their tectonic implications          下载免费PDF全文

Chang‐Sik Cheong  Namhoon Kim  Hui Je Jo  Moonsup Cho  Sung Hi Choi  Hongying Zhou  Jian‐zhen Geng 《地学学报》2015,27(2):97-105

The Mesozoic tectonic architecture of the Korean peninsula is largely governed by the continental collision between the North and South China blocks. Zircon Hf isotopic compositions presented in this study and whole‐rock geochemical and Sr‐Nd isotope data in the literature collectively suggest that the lithophile‐elements‐enriched signature of the Late Triassic post‐collisional plutons from the Gyeonggi massif in central Korea is a primary feature inherited from the metasomatized mantle lithosphere. Highly negative zircon ε_Hf (t) values (?23 to ?19) of plutons from the middle and eastern parts of the massif indicate an ancient metasomatism of their mantle source. Distinctly higher zircon ε_Hf (t) values (?15 to ?12) from the southwestern plutons are ascribed to a contribution from an accreted component of the South China‐like block. The involvement of asthenospheric mantle is not recognized in zircons from either group. The implications of these isotopic features are discussed in the context of Mesozoic collisional tectonics.  相似文献   

A new direction in coastal management   总被引：2，自引：0，他引：2  

So-Min Cheong   《Marine Policy》2008,32(6):1090-1093

This paper argues for a stronger integration of marine sciences and coastal management studies that generates better formulated marine policies and viable policy implementation strategies. Integration of natural and social sciences in environmental management has surfaced as a key issue recently in the fields of sustainability science, ecosystem-based management, and social–ecological resilience. This paper promotes such trend in marine studies, and examines the rationale, progress, and examples of the integration.  相似文献   

韩国东海Ulleung盆地天然气水合物沉积层的地震属性分析     

Snons Cheong  Wonsik Kim  Namhyung Koo  孙萍 《海洋地质前沿》2009,25(2):22-23

地震属性可以由多种地震子波的特征来定义。并且根据不同的标准分类。选择叠前地震数据特征可提供丰富的诸如偏移和方向的资料，此次研究中，我们将限制叠后地震数据以提取地震属性，叠后地震数据可以通过子波特征和瞬时特征来分类。  相似文献   

The Global/Regional Integrated Model system (GRIMs)   总被引：5，自引：0，他引：5  

Song-You Hong  Hoon Park  Hyeong-Bin Cheong  Jung-Eun Esther Kim  Myung-Seo Koo  Jihyeon Jang  Suryun Ham  Seung-On Hwang  Byoung-Kwon Park  Eun-Chul Chang  Haiqin Li 《Asia-Pacific Journal of Atmospheric Sciences》2013,49(2):219-243

  相似文献   

Multivariate statistical analysis to identify the major factors governing groundwater quality in the coastal area of Kimje,South Korea     

Ji‐Hoon Kim  Rak‐Hyeon Kim  Jeongho Lee  Tae‐Jin Cheong  Byoung‐Woo Yum  Ho‐Wan Chang 《水文研究》2005,19(6):1261-1276

The main purpose of this study is to identify the major factors affecting groundwater quality by means of multivariate statistical analysis of the physico‐chemical compositions. Cluster analysis results show that the groundwater in the study area is classified into four groups (A, B, C and D), and factor analysis indicates that groundwater composition, 81·9% of the total variance of 17 variables, is mainly affected by three factors: seawater intrusion, microbial activity and chemical fertilizers. These results might be related to the geographical characteristics of the study area. The main influence on groundwater in groups B, C and D, which are close to the Yellow Sea and contain reclaimed areas, is the seawater intrusion by the present seawater, the trapped seawater, and microbial activity. Group A, however, has been used for agriculture for a long time, and thus groundwater in this group has been largely affected by chemical fertilizers. As groundwater flows from group A to group D according to its path, the governing factor of the groundwater quality gradually changes from chemical fertilizers to microbial activity and seawater intrusion. Copyright © 2004 John Wiley & Sons, Ltd.  相似文献