간행물
한국지구과학회지 KCI 등재 The Journal of The Korean Earth Science Society
- 발행기관 한국지구과학회
- 자료유형 학술지
- 간기 격월간
- ISSN 1225-6692 (Print)2287-4518 (Online)
- 수록기간 1979 ~ 2024
- 주제분류 자연과학 > 지구과학 자연과학 분류의 다른 간행물
- 십진분류KDC 450DDC 550
권호리스트/논문검색
제11권 제1호 (1990년 4월) 7건
1.
1990.04
구독 인증기관 무료, 개인회원 유료
Around Umsong-Jeungpyeong, the Cretaceous sedimentary basin is located along NNE direction which can be associated with Kongju basin. These basins are studied in terms of field geology, stratigraphy, paleontology, geological structure and geophysical prospecting. Chopyung Groups were deposited in the Cretaceous period : Baegyari Formation conformably over Chopyung Formtion in fault-generated tan and river basin with lake characteristics in the central part. The fossils found for the first time in this study area are Onychiopsis elongata and Euestheria, and they suggest the Chopyung Groups may be identified with the Naktong Subgroups of Kyungsang Basin. After depositon of Chopyung Groups, igneous activity became vigorous : granite intrusion in westside, andesite and basalt in east fault line and tuffaceous deposits. The gravity survey shows high Bouguer anomaly over andesites and metamorphic rocks, and low in granite area. The mean depth of density discontinuity boundary seems to be 1200∼1400m. The electric resistivity survey suggests that the cast boundary of the basin be a vertical fault.
4,300원
2.
1990.04
구독 인증기관 무료, 개인회원 유료
Using a numerical model, the tidal phenomena in the Korea Straits were studied. The co-tidal and co-range charts of the main four tidal components of M2, S2, K1 and O1, were made. The tidal range for M2 tide in the southern coast is more than 200cm, and as going to the Japan Sea it abruptly decreased to only few centimeters around the amphidromic point which locates at the southern part of the Japan Sea. And the overall features of the other tides are similar to the M2 tide. Each calculated charts were relatively coincided with those of observed tide by Ogura(1933). For storm surge, the typhoon Thelma in July, 1987, was modelled. The water level by the pressure and wind under the elimination of the tidal effects shows the anti-clockwise rotation and the valid concentric contour around the typhoon center. As the typhoon approaches to the Japan Sea the water level of the eastern coast of Korea is smaller than that of the southern coast which has over 50㎝surge due to the shallow depth. The entire features of water level were comparatively coincident with the observed.
4,000원
3.
1990.04
구독 인증기관 무료, 개인회원 유료
The measurements of uranium with nuclear fission track technique on the Holocene carbonate components and submarine cements in South Florida, U.S.A. and the Bahamas have allowed not only characteristic uranium concentrations but also spatial distribution. Relatively high uranium concentrations were found in coral skeletons (2.5 ppm). ooids (2.8 ppm), and peloids (3.2 ppm) whereas most of the modern calcareous organisms contain low uranium concentrations. Varied uranium concentrations were found in submarine cements; more than 3 ppm in acicular aragonite, 2 to 3 ppm in micritic Mg-calcite in inter- and intraparticle pores, and 0.7 to 2.8 ppm in micirtic envelopes. Heterogeneous distributions of uranium were quite common in both skeletons and inorganic carbonates. Marine organisms seem to discriminate against uranium while they are alive and thereby they contain low uranium concentrations whereas inorganic carbonate components incorporate uranium in equilibrium with seawater and thereby the contain high uranium concentration. In incorporation of uramiun into carbonate componets physiology and mineralogy seem to be important in organism whereas minerablogy and CO₂ content of seawater are thought to be important in inorganic components. Characteristic uranium concentrations and spatial distribution pattern in modern carbonates suggest that uranium can be used as a powerful diagenentic indicator in studying ancient carbonate rocks. This study reveals that the fission track technique is an advantageous tool in studying petrography
5,100원
4.
1990.04
구독 인증기관 무료, 개인회원 유료
This study is directed to study of the stratigraphy, sedimentary rocks and depostitional environment of the Jinju Formation in the Jinju-Sacheon area. The Jinju Formation in the area is subdivided into the lower member, middle member and upper member by their lithologic characteristics. Each member of the Jinju Formation is composed mianly of grey arkose sandstone, sandy shale and dark grey shale. A few thin layers of limestone and calcareous shale are intercalated in the upper parts. As in most places, sand shale of the formation shows onionJstructures and contains many nodules. The grain particle analysis of the sandstone samples were obtained moderately sorted, positive skewness and meso-kurtic. The significant sedimentary structures such as the pillow, cone-in-cone, large scale suncrack, ridge-type cross-bedding, cylindrical muddy lime concretion and stromatolites are sampled from the non-marine Cretaceous Jinju Formation in the Kyeongsang basin, Korea. The fades fossils of the Cretaceous snakeflies, freshwater fishes, cyzicuses, cladophlebis spp., and plant stems were excavated from the black shale of the formation. The paleocurrent study, was carried out by means of the statistical analysis of the cross-stratification, ripple mark, slump structure, and parting lineation, which are palecocurrent structure. The investigator presents his own computer programming process for the calculation of statistical parameters. The paleocurrent direction, depositional strike, source area, and the depositional center of the basin of the Jinju Formation are judged to be southeast, northeast, northwest, and southeast, respectively. The depositional environment on the formation in the studied area is determined definitely the fluvial environment in view of the interdisciplinary assessment of the analysis results of paleocurrent structures listed above.
4,000원
5.
1990.04
구독 인증기관 무료, 개인회원 유료
The major product of wolframite series in Korea are wolframite and ferberite. In Cheolam silver deposits, however, huebnerite is occurred. The formation conditions of huebnerite and ferberite are similar, but that of huebnerite is higher Mn/Fe ratio and neutral or alkaline than ferberite. Based on E.P.M.A. data, chemical composition of the huebnerite from Cheolam silver deposits is (Mn_(0.89) Fe_(0.11))WO₄. The measured cell dimensions of the huebnerite is a_o=4.825Å, b_o= 5.755Å, c)o=4.997Å, the angle β=91.03° To compared with huebnerite will be occurred in the other districts, reflectivity and absolute hardness(VHN) were measured and described.
4,000원
6.
1990.04
구독 인증기관 무료, 개인회원 유료
Granitic rocks around Namsan area, Kyeongju, were studied from petrographic and petrochemical point of view. The Naman granite is generally medium to coarse grained hypersolvus granite dominated by pink K-feldspar and quartz, and shows miarolitic cavities. K-feldspar is the most abundant mineral(57-64% in volume), forming tabular microperthite crystals, or granophyric intergrowths with quartz. Plagioclase($lt;0.3%) appears only as perthitic streaks in microcline perthite. It contains biotite(X=pale brown, Y=Z=brown), blue amphibole(X=deep blue, Z=pale to inky blue) and fluorite. Petrochemically the Namsan granite is distinguished from the Bulgugsa granites of I-type, by higher abundance of SiO₂, K₂O, (Na₂O+K₂O) and large highly charged canons such as Nb, Y, Zr and the REE, and lower abundance of Al₂O₃, MgO, CaO, Ba, Sr, Eu, Co, Sc, Cr, and Ni. The Namsan granite shows higher strontium initial ratio(^(87)Sr/^(86)Sr) of 0.713±0.002, and the age yielded 51±1.4Ma(Rb-Sr age) to 49.3±0.9Ma(K-Ar age). These petrographic and petrochemical characteristics indicate that the Namsan granite belongs to the A-type granitoid series. And the Namsan granite is originated by direct, high-temperature partial melting of a melt depleted I-tape source rock in the lower crust.
4,900원
7.
1990.04
구독 인증기관 무료, 개인회원 유료
There has been a tremendous expansion in the use of paleomagnetic methods to detect and measure the relative movement of different tectonic units on both a global and subcontinental scale, and consequently the fifth earth science curriculum which starts from 1990 emphasizes more on paleomagnetism than that of the previous. And earth science teachers will, therefore, need materials to teach the students paleomagnetism or plate tectonics. This paper was written to fulfill such a requirement by offering earth science teachers the basic principles and methods of paleomagnetism and paleomagnetic data of Korea.
4,000원
