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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of the Korean earth science society
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Journal DOI :
The Korean Earth Science Society
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Volume & Issues
Volume 18, Issue 6 - Dec 1997
Volume 18, Issue 5 - 00 1997
Volume 18, Issue 4 - 00 1997
Volume 18, Issue 3 - 00 1997
Volume 18, Issue 2 - 00 1997
Volume 18, Issue 1 - 00 1997
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Abnormally high contents of cadmium in the sphalerite from the Boseong-Jangheung gold-silver mine area, Cheollanamdo Province
Heo, Cheol-Ho ;
Journal of the Korean earth science society, volume 18, issue 2, 1997, Pages 85~85
Cadmium occurs as a minor element in sphalerite[(Zn,Fe)S] from the Boseong-Jangheung gold-silver mine area. The cadmium contents in sphalerite, analyzed with EPMA, were discussed to deduce its natural sources in terms of bedrock geochemistry, in order to preliminarily reconnoiter the potential cadmium contamination in mine districts. Cadmium contents of sphalerites from the Au-Ag mines (Bodeok, Mundeok, Jeonbo, Boknae, Keumsan) in the Boseong-Jangheung area are considerably high (average = 3.96 wt.% Cd; maximum = 11.2 wt.% Cd), compared with cadmium contents of sphalerites (average = 0.5 wt.% Cd; maximum = 4.4 wt.% Cd) in the world. Our data suggest that the Boseong-Jangheung area has an important potential to be an cadmium contamination source.
Stratigraphy, Sedimentary Facies and Diatoms of the Tidal Sediments in Hampyeong Bay, West Coast of Korea
Lee, Yeong-Gil ; Park, Yong-An ;
Journal of the Korean earth science society, volume 18, issue 2, 1997, Pages 90~90
Stratigraphy, sedimentary facies and micropalontological studies based on diatom assemblage analysis of the tidal sediments in Hampyeong Bay, west coast of Korea were carried out by 9 vibracores collected from the study area. A total of 6 sedimentary facies are recognized from the cores. Among them, mud, sandy mud and gravelly sand facies are dominant. The gravel facies are also frequently interbedded in the sequence. Biogenetic structures such as burrow and non-biogenetic primary sedimentary structures such as remanant laminae are also frequently found in the sequence. The tidal deposits of the study area are divided into Holocene deposits (Unit I) and pre-Holocene deposits (Unit II) by the erosional surface of semi-consolidated oxidized bed. The oxidized bed which is composed mainly of yellowish or yellowish brown mudy sediments is inferred as late Pleistocene sediments and correlated with Kanweoldo Formation widely distributed in bottom of Yellow Sea. The oxidized bed is characterized by homogeneous sedimentary structure, presence of cryoturbated structure, ocurrence of crab burrow trace fossil and absence of microfossils. Diatom frustules occurr only in upper part of Holocene tidal deposit. But, they don't occurr in the lower part than the upper part of Holocene tidal deposits except two or three beds which are occurred very poorly in abundance. A total of 153 species and varietes, belonging to 49 genera has been identified in the present study. Among them, Palalia sulcata is the most abundant species. Cyclotella stylorum, Thalassionema nitzschioides, Coscinodiscus nitidus, Nitzschia granulata, N. cocconeiformis, Actinocyclus octonarius, Actinoptychus undulatus, Thalassiosira tenera, T. eccentrica, and T. oestrupii are also occurrs frequently in abundance. Most of the diatoms found in this study are marine, marine-brackish water species, and tychopelagic and meroplanktonic species. Also, most of the species are low salinity coastal to littoral and inner neritic species. The ecological properties of the diatoms indicate that the diatomaceous sediments were deposited under inner bay tidal environments such as the recent marine environments of the study area which was more strongly influenced by temperate to warm water than cold water. Not only in the oxidized beds but also in the upper part of Holocene tidal deposits the oxidized yellowish brown muddy sand are frequently interbedded. These indicates that the sediments were intermittently exposed to the air condition during the deposition of the sediments.
Orgin of Granitoids in the Southwestern Part of Korea Based on Sr, Nd Isotopic Ratio
Sin, In-Hyeon ; Kim, Hui-Nam ;
Journal of the Korean earth science society, volume 18, issue 2, 1997, Pages 99~99
Sr and Nd isotopic compositions were determined for late Cretaceous granitoids at the Haenam, Wando, Gangjin-Janghung and Namhae areas in the southwestern part of Korea. The granitoids in these areas are distributed in the shape of a resurgent cauldron. Eight samples of Haenam granophyre give a defined Nd isotope ratios of 0.512180∼0.512259 and a ε Nd values of - 6.53∼-8.15, ε Sr values of +51.49∼+66.48 and model age of 1.28∼1.60 Ga.. Four samples of Wando granophyre give a defined Nd isotope ratios of 0.512228∼0.512289 and ε Nd values of -6.74∼-8.00, ε Sr values of +54.88∼+78.98 and model age of 1.14∼1.42 Ga.. Four samples of Gangjin-Janghung granophyre give a defined Nd isotope ratios of 0.511821∼0.511922 and a Nd values of -13.24∼-15.15, ε Sr values of +132.59∼+161.53 and model age of 1.77∼1.95 Ga.. Three samples of Namhae micrographic granite give a defined Nd isotope ratios of 0.512591∼0.512626 and ε Nd values of -0.24∼+0.18, ε Sr values of +12.01∼+13.48 and model age of 0.99∼1.02 Ga.. The above Sr and Nd isotope ratios suggest that the granitoids of Yeongdong-Kwangju depression and Gyeongsang basin are different to their source material. The granophyre of Haenam and Wando area may formed by partial melting of lower crust, which are similar to the Cretaceous granitoids of Sanyo and Ryoke area of the Japan. The granophyre of the Gangjin-Janghung area may be derived from partial melting of continental crust. The micrographic granites of Namhae area in the Gyeongsang basin, however, are considered to generated by partial melting of upper mantle materials.
Historical review and prospect of paleobotanical study in Korea
Journal of the Korean earth science society, volume 18, issue 2, 1997, Pages 105~105
The plant fossils occurred from the Precambrian to Cenozoic in Korea have been investigated by many authors. Since the first paleobotanical contribution was given by Felix(1887), many papers have been published mainly by the Japanese authors before 1945 and then mainly by the Korean authors. I reviewed these data published from 1887 to 1996 and discussed many problems to be solved in future.
Shallow Seismic Reflection Method using an Accelerated Weight Drop Seismic Source
Journal of the Korean earth science society, volume 18, issue 2, 1997, Pages 119~119
Shallow seismic reflection surveys were performed using an accelerated weight drop seismic source to examine the applicability of the seismic source in the field, and to study shallow subsurface structure of three different sites in Pusan. A CDP stacking of 1200% coverage was adopted in Dong-A University site, and an optimum window technique(100% coverage) was used in Eulsuk-do site. In Young-do site seismic data were interpreted by a refraction method as well as a reflection method. With the accelerated weight drop seismic source the elastic wave of high energy can be generated repeatedly, and the mobility of the source in the field can be secured. The bedrock and the overburden soil layers can be mapped efficiently with the shallow seismic reflection method at various geological formations where the limitation of the spread length with respect to the depth of the target layer exists.
The Ionospheric Conductivity Distribution over the Entire Polar Ionosphere
Journal of the Korean earth science society, volume 18, issue 2, 1997, Pages 126~126
An improved ionospheric conductance model based upon ground magnetic disturbance data is proposed. For this purpose empirical relationships between the ionospheric conductance deduced from the Chatanika incoherent scatter radar and magnetic disturbance simultaneously recorded from the College magnetic station are examined. Since it has been reported that different regions of the auroral electrojet is governed by different physics (e.g., Foster, 1987), however, it is desirable to reflect such findings. To accommodate them the entire auroral electrojet system has been divided into many small regions in terms of the the signs of ΔH and ΔZ as well as by magnetic local time (MLT). And the empirical relationship over each region of the electrojet is obtained separately. The ionospheric conductance distribution over the entire polar region based on these empirical formulas is reconstructed by employing the average magnetic disturbance data measured from the Alaska meridian chain of magnetometers during the International Magnetospheric Study (IMS) as input. The result thus obtained is compared with a conductance model based on electron precipitation data (Hardy et al., 1987) and found that the agreement is satisfactory in terms of magnitude and distribution pattern. It is further attempted to obtain the average energy and energy flux of precipitating electrons by combining these empirical formulas with the ones proposed by Robinson et al. (1987). The similarity between the global distribution pattern of these quantities estimated from this study and those reported by Hardy et al. (1985) is also notable. Thus, we propose that the present conductance model can be used to complement more direct measurements in simulating the global distribution which is indispensable in the study of the electrodynamics of the entire polar ionosphere.
The Teaching Effect Based on Psychological Hierarchy of Earth Science Concepts in Middle School Students
Jeong, Jin-U ;
Journal of the Korean earth science society, volume 18, issue 2, 1997, Pages 138~138
The purpose of this study is to investigate the psychological hierarchy structure of the Earth Science concepts and to determine the effective teaching order by comparing the teaching effects of the psychological hierachy order with those of teaching order of the current text. To study this purpose, key concepts were selected by the tasks analysis in three units. Concept formation tests were developed and ordering thoery was used to identify middle school students' psychological hierachy. To test effects of the psychological hierarchy, teaching with psychological hierarchy order was applied to experimental group and teaching with concept order descripted in the current text was applied to control group. The major results of this study are as following: 1. The students' psychological hierarchy structure are not always consistent with logical hierarchy structure in the current texts. 2. The mean score of experimental group applied psychological hierarchy order was significantly higher(p$lt;.05) than the control group in the concept achievement.
Organic Metamorphism of the Coals in the Chungnam Coalfield, Korea
Choe, Seok-Won ;
Journal of the Korean earth science society, volume 18, issue 2, 1997, Pages 146~146
The object of this study is to clarify the degree of organic metamorphism in the Late Triassic coal-bearing Chungnam Coalfield using vitrinite reflectance and crystallininity by the X-ray diffraction analysis as rank parameters, and to discuss geological background of coalification. R_(max) values range from 4.55% to 6.48%, which indicate the coals belong to anthracite to meta-anthracite stage in rank of ASTM classification. X-ray diffraction shows very distinct peak from 25.51 to 25.58 2θ, which indicates an average molecular repeat distance of approximately 3.49Å in the Ovals. Integral breadth of the coals ranges from 6.06 to 5.98. Bireflectance varied from 1.79 to 3.35. Above mentioned characteristic features are inferred as a manifestation of higher temperature and pressure organic metamorphism. R_(max) begin to decrease at R_(max) 5.5% and this pattern is in striking contrast to that of the European coals. Bireflectance values tend to increase with increasing of R_(max) values. The increasing modes of the R_(max) and crystallininity do not always correspond each other with progressing of metamorphism. In each unit of formations, coals of the Amisan Formation are the most advanced in coalification and degree of crystallinity. Anthracitization was took placed post-Daebo Orogeny and was caused by the thermal effects of the intrusion of the Jurassic Daebo Granite. Judging from the fossil plants and paleomagnetic data, it is inferred that formation of coal deposits was formed in the subtropical climate and the Korean Peninsula was paleogeographically situated near horse-latitudes of lower latitudes than present geographic position in Late Triassic time.
G-band Strength and Its Application to Determine Carbon Abundance in Twelve Algol Secondaries
Journal of the Korean earth science society, volume 18, issue 2, 1997, Pages 155~155
G-band strengths for twelve Algol secondaries whose spectral types are determined spectrophotometrically are measured using the time-resolved spectra as a step to know the carbon abundance anomaly on the surface of Algol secondaries. The carbon abundances of these Algol secondaries are determined by the comparison of the G-band strengths by the weak G-band stars and abundance standard stars whose carbon abundances are already known. The carbon abundances of all the twelve Algol secondaries are revealed less than the mean value of log ε(C) = 8.43 for G, K type giants as predicted by stellar evolution models. The amount of the difference in carbon abundances between each Algol secondary and normal G, K type giants is probably related with the mass transfer scenario in Algol systems.