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51.
Discovery of Pyrrhotite-Chalcopyrite-Bearing Amphibole Megacrysts in Tongling Area, Anhui Province 总被引:1,自引:0,他引:1
Some pyrrhotite-chalcopyrite-bearing amphibole megacrysts (including pyroxene megacrysts) were discovered in Mesozoic augite diorite-porphyrite at Caoshan in Tongling area, Anhui Province. The amphibole megacrysts, belonging mainly to pargasite and magnesiohastingsite, are characteristic of the amphibole composition derived from mantle and crystallized in lower crust. In general, the aggregates of pyrrhotite-chalcopyrite take the shapes of cylinder and sphere. Three occurrences have been recognized in the amphibole megacrysts: parallel linear, bunchy and scattered. The unique cylinder-like shape of the aggregates and remarkable Ni-poor sulfides in Caoshan are distinctively different from the spherical Ni-rich sulfides in pyroxene megacrysts and any other kinds of megacrysts. In terms of composition, the amphibole megacrysts and their sulfides in Caoshan are similar to those in the pyroxenite xenoliths in Qilin, Guangdong Province. In terms of origin, the pyrrhotite-chalcopyrites as exsolution products resulted from the subsolidus re-equilibration of sulfide solid solution within amphibole megacrysts.amphibole megacrysts were first discovered inside and outside China. This discovery is important for the study of regional magma evolution and its associated mineralizations and ore sources as well. 相似文献
52.
Yong-Woong Kim 《GeoJournal》2001,53(1):5-15
In the early stages of economic development in Korea, national territorial planning was used as a policy tool to guide spatial structure and to provide physical infrastructure for urban and industrial development. Such a top-down approach was inevitable because Korea maintained the centralized political and government system until the early 1990s. Circumstances, however, have changed recently since the 1990s with progress in democratization and localization. In addition, forces of globalization are making significant impacts on the parameters of national territorial planning. Reflecting these changes in both internal and external conditions, the Fourth National Territorial Plan (2000–2020) has adopted a different approach from the past three territorial plans. This paper reviews the socio-economic background that necessitated such changes in approaches to national territorial planning. A major thrust of the Fourth Plan, a focus on emergent or anticipated planning issues in Korea, is discussed. Finally, the paper examines the rationale for long-term strategic planning in the highly fluctuating situation facing Korean society in the new century. 相似文献
53.
Comparison of the Ordovician-Carboniferous Boundary Between Korea and NE China: Implications for Correlation and Tectonic Evolution 总被引:2,自引:0,他引:2
There is a great hiatus between Ordovician and Carboniferous strata in the Northeast China and Korean Peninsula. In order to understand geology and tectonic evolution, and to find out the similarities and differences in both regions, two sections in the Western Hill near Beijing in NE China and several sections in the Korean Peninsula were selected to examine their geologic boundaries between Lower and Upper Paleozoic strata to compare their characteristic features. At four sites in the two sections in the Western Hill near Beijing were examined their contact relations. The Hui Yu section is the same horizon where one site is top of a quarry hill and the other of down hill. Mid-Carboniferous Qingshuijian Formation rests on the Ordovician Majiagou Formation. Limestone beds are more commonly intercalated with shale and sandstone at site 2 of the Hui Yu section, while at site 1, conglomerate beds are dominant. Site 1 of the Se Shu Fen section shows eroded and concealed karst topography and conglomerate beds are intercalated within shale beds. Silurian and Devonian strata are absent in these areas. In the Korean Peninsula, most O-C contacts occur between Ordovician limestone formation and Carboniferous strata, although Silurian strata occur beneath the Carboniferous strata in the Jeongseon area and Pyeongnam Basin. Most contact relations are parallel unconformity and angular unconformity is rarely seen. The O-C relations in both regions are similar to each other, and these indicate that the Korean Peninsula was located near or belonged to the Sino-Korean paraplatform during Paleozoic time. 相似文献
54.
James Glimm Shuling Hou Hongjoong Kim Yoon-ha Lee David H. Sharp Kenny Ye Qisu Zou 《Computational Geosciences》2001,5(3):173-197
We consider numerical solutions of the Darcy and Buckley–Leverett equations for flow in porous media. These solutions depend on a realization of a random field that describes the reservoir permeability. The main content of this paper is to formulate and analyze a probability model for the numerical coarse grid solution error. We explore the extent to which the coarse grid oil production rate is sufficient to predict future oil production rates. We find that very early oil production data is sufficient to reduce the prediction error in oil production by about 30%, relative to the prior probability prediction. 相似文献
55.
Hyeong Soo Kim Jin-Han Ree Jeongmin Kim 《International Journal of Earth Sciences》2012,101(2):499-501
56.
Namin Koo Kwon-Rae Kim Youn-Jung Choi Sang-Hwan Lee Gary Owens Jeong-Gyu Kim 《Environmental Earth Sciences》2012,65(3):689-697
To determine the appropriate allocation of resources for the future restoration of the abandoned mining district of Kangwon
in Korea, identification of the main pollutants and the main sources discharging these pollutants is crucial. Therefore, a
2-year study was undertaken to quantify the amount of pollutants in the Uchen stream (a potential sink for contamination),
which runs through the district, and to determine the potential sources of these pollutants, including mine drainage and soil.
Arsenic (As) was the main pollutant in mine drainage and soils showing concentrations above the Korean regulated standard
levels of 50 μg L−1 and 50 mg kg−1 for water and soil, respectively. In addition, the pollution index (PI) showed that mine drainages were polluted by As to
a moderate (2 ≤ PI < 3) or strong (4 ≤ PI < 5) degree. Consequently, As load in mine drainage and soil contributed to increased
amounts of As in the stream. The As loads in mine drainages (11 and 587 g month−1 for mine adit 1 and 2, respectively) accounted for only 9% of the total As load to the stream (6,378 g month−1); and the influence of mine drainages on As contents in the stream was more reliant on the total volume of mine drainage
generated rather than the As concentration in the mine drainage. Approximately 91% of the As in the stream was derived from
the soils within the study area. 相似文献
57.
Paul Duuring Stephen M. Rowins Bradley S. M. McKinley Jenni M. Dickinson Larry J. Diakow Young-Seog Kim Robert A. Creaser 《Mineralium Deposita》2009,44(4):463-496
The Toodoggone district comprises Upper Triassic to Lower Jurassic Hazelton Group Toodoggone Formation volcanic and sedimentary
rocks, which unconformably overlie submarine island-arc volcanic and sedimentary rocks of the Lower Permian Asitka Group and
Middle Triassic Takla Group, some of which are intruded by Upper Triassic to Lower Jurassic plutons and dikes of the Black
Lake suite. Although plutonism occurred episodically from ca. 218 to 191 Ma, the largest porphyry Cu–Au ± Mo systems formed
from ca. 202 to 197 Ma, with minor mineralization occurring from ca. 197 to 194 Ma. Porphyry-style mineralization is hosted
by small-volume (<1 km3), single-phase, porphyritic igneous stocks or dikes that have high-K calc-alkaline compositions and are comparable with volcanic-arc
granites. The Fin porphyry Cu–Au–Mo deposit is anomalous in that it is 16 m.y. older than any other porphyry Cu–Au ± Mo occurrence
in the district and has lower REEs. All porphyry systems are spatially restricted to exposed Asitka and Takla Group basement
rocks, and rarely, the lowest member of the Hazelton Group (i.e., the ca. 201 Ma Duncan Member). The basement rocks to intrusions
are best exposed in the southern half of the district, where high rates of erosion and uplift have resulted in their preferential
exposure. In contrast, low- and high-sulfidation epithermal systems are more numerous in the northern half of the district,
where the overlying Hazelton Group rocks dominate exposures. Cogenetic porphyry systems might also exist in the northern areas;
however, if they are present, they are likely to be buried deeply beneath Hazelton Group rocks. High-sulfidation epithermal
systems formed at ca. 201 to 182 Ma, whereas low-sulfidation systems were active at ca. 192 to 162 Ma. Amongst the studied
epithermal systems, the Baker low-sulfidation epithermal deposit displays the strongest demonstrable genetic link with magmatic
fluids; fluid inclusion studies demonstrate that its ore fluids were hot (>468°C), saline, and deposited metals at deep crustal
depths (>2 km). Sulfur, C, O, and Pb isotope data confirm the involvement of a magmatic fluid, but also suggest that the ore
fluid interacted with Asitka and Takla Group country rocks prior to metal deposition. In contrast, in the Shasta, Lawyers,
and Griz-Sickle low-sulfidation epithermal systems, there is no clear association with magmatic fluids. Instead, their fluid
inclusion data indicate the involvement of low-temperature (175 to 335°C), low-salinity (1 to 11 equiv. wt.% NaCl) fluids
that deposited metals at shallow depths (<850 m). Their isotope (i.e., O, H, Pb) data suggest interaction between meteoric
and/or metamorphic ore fluids with basement country rocks. 相似文献
58.
We examined the anthropogenic and natural causes of flood risks in six representative cities in the Gangwon Province of Korea.
Flood damage per capita is mostly explained by cumulative upper 5% summer precipitation amount and the year. The increasing
flood damage is also associated with deforestation in upstream areas and intensive land use in lowlands. Human encroachment
on floodplains made these urban communities more vulnerable to floods. Without changes in the current flood management systems
of these cities, their vulnerability to flood risks will remain and may even increase under changing climate conditions. 相似文献
59.
This study has evaluated the main hydrogeochemical characteristics that affect the quality of shallow groundwater in the coastal area at Kimje in South Korea. In this area, the chemical composition of groundwater is mostly classified into Na+?Cl? and Ca2++Mg2+?NO3-+Cl? types. These types are affected by three major factors: seawater intrusion, fertilizers and redox processes. The Na+?Cl? type, which is generally localized in the coastal area, shows typical characteristics of groundwater affected not only by modern seawater but also by old seawater residing in the reclaimed land. In contrast, the Ca2++Mg2+?NO3-+Cl? type, which is usually found inland, is very contaminated by fertilizers. As groundwater flows from the inland area to the coast, the redox condition changes from an oxic condition to a suboxic/anoxic condition. In addition, the reclamation has caused a large amount of underlying organic matter. These effects provide optimum conditions for the occurrence of redox processes in the coastal area. 相似文献
60.
Effects of natural and calcined oyster shells on Cd and Pb immobilization in contaminated soils 总被引:5,自引:0,他引:5
Yong Sik Ok Sang-Eun Oh Mahtab Ahmad Seunghun Hyun Kwon-Rae Kim Deok Hyun Moon Sang Soo Lee Kyoung Jae Lim Weon-Tai Jeon Jae E. Yang 《Environmental Earth Sciences》2010,61(6):1301-1308
In Korea, soils adjacent to abandoned mines are commonly contaminated by heavy metals present in mine tailings. Further, the
disposal of oyster shell waste by oyster farm industries has been associated with serious environmental problems. In this
study, we attempted to remediate cadmium (Cd)- and lead (Pb)-contaminated soils typical of those commonly found adjacent to
abandoned mines using oyster shell waste as a soil stabilizer. Natural oyster shell powder (NOSP) and calcined oyster shell
powder (COSP) were applied as soil amendments to immobilize Cd and Pb. The primary components of NOSP and COSP are calcium
carbonate (CaCO3) and calcium oxide (CaO), respectively. X-ray diffraction, X-ray fluorescence and scanning electron microscope analyses conducted
in this study revealed that the calcination of NOSP at 770°C converted the less reactive CaCO3 to the more reactive CaO. The calcination process also decreased the sodium content in COSP, indicating that it was advantageous
to use COSP as a liming material in agricultural soil. After 30 days of incubation, we found that the 0.1 N HCl-extractable
Cd and Pb contents in soil decreased significantly as a result of an increase in the soil pH and the formation of metal hydroxides.
COSP was more effective in immobilizing Cd and Pb in the contaminated soil than NOSP. Overall, the results of this study suggest
that oyster shell waste can be recycled into an effective soil ameliorant. 相似文献